Miniature oil-tight push button and selector switch assembly and improved contact unit therefor

[57] ABSTRACT

A plurality of modular contact units are adapted for attachment to a housing containing an operating means which may be of either the push-button or selector switch variety. Each contact unit comprises a single pair of contacts and indicating means to display the condition of the pair of contacts. Camming means may be interchangeably attached to the operating means externally of the switch units. Selector switch operation provides maintained switching for up to eight positions, momentary switching, or momentary-maintained switching. Selector switch Cams may be double stacked to provide a maximum number of switching programs with a minimum number of parts. The operating means may be illuminated or non-illuminated and is adaptable for use as a pilot light or a push-to-test unit.

Claims, 38 Drawing Figures

<img file="US3740501A_D0001.tif" />

Patented June 19, 1973

3,740,501

Sheets-Sheet 1

<img file="US3740501A_D0002.tif" />

FIG. I

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<img file="US3740501A_D0004.tif" />

FIG. 3

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<img file="US3740501A_D0006.tif" />

FIG. II

INVENTORS RUDOLF H.KIESSLING RICHARD C. ROTHWEILER

<img file="US3740501A_D0007.tif" />

Patented June 19, 1973

3,740,501

Sheets-Sheet 2

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INVENTORS

RUDOLF H.KIESSLING RICHARD C. ROTHWEILER

<img file="US3740501A_D0009.tif" />

Patented June 19, 1973

3,740,501

Sheets-Sheet 3

<img file="US3740501A_D0010.tif" />

Patented June 19, 1973

3,740,501

Sheets-Sheet 4

<img file="US3740501A_D0011.tif" />

Patented June 19, 1973

3,740,501

Sheets-Sheet 5

<img file="US3740501A_D0012.tif" />

INVENTORS

RUDOLF H.KIESSLING RICHARD C. ROTHWEILER

<img file="US3740501A_D0013.tif" />

FIG. 22

Patented June 19, 1973

3,740,501

Sheets-Sheet 6

FIG. 23

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<img file="US3740501A_D0015.tif" />

<img file="US3740501A_D0016.tif" />

<img file="US3740501A_D0017.tif" />

INVENTORS

RUDOLF H.KIESSLING RICHARD C. ROTHV/EILER

<img file="US3740501A_D0018.tif" />

Patented June 19, 1973

3,740,501

Sheets-Sheet Ί

<img file="US3740501A_D0019.tif" />

<img file="US3740501A_D0020.tif" />

<img file="US3740501A_D0021.tif" />

FIG.3I

<img file="US3740501A_D0022.tif" />

<img file="US3740501A_D0023.tif" />

Patented June 19, 1973

3,740,501

Sheets-Sheet 8

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FIG. 34

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<img file="US3740501A_D0026.tif" />

FIG. 38

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FIG. 36

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FIG. 37

INVENTORS RUDOLF H. KIESSLING RICHARD C. ROTHWEILER

<img file="US3740501A_D0029.tif" />

3,740, ·1

MINIATURE OIL-TIGHT PUSH BUTTON AND SELECTOR SWITCH ASSEMBLY AND IMPROVED CONTACT UNIT THEREFOR

This invention relates to switches, and particularly to a switch characterized by having a number of inter- 5 changeable parts for selective attachment to certain common parts for adapting the switch, with a minimum total inventory of parts, to perform a large variety of switching arrangements.

More specifically the switch is adaptable to function 10 with a push button operator and stem or with a selector switch operator and stem. Up to four contact modules can be independently controlled in sequences which can be chosen by selectively connecting various cams to the stem. Selector switch operation provides both 15 momentary and maintained operation for two or three position switching while maintained action alone can be provided for up to eight positions.

Both the push button and selector switch operators may be illuminated and the push button switch assem- 20 bly is adaptable for use as a pilot light or push-to-test unit.

These and other advantages will become apparent from the following description in which reference is made to the drawings wherein: 25

FIG. 1 is a side elevational view of a push button switch assembly made in accordance with the present invention and mounted on a panel;

FIG. 2 is a rear elevational view of the push button switch assembly of FIG. 1 with contact modules and a ³θ push button cam removed;

FIG. 3 is an enlarged cross-sectional view of the push button switch assembly of FIG. 1 taken along the line 3-3 of FIG. 2;

FIG. 4 is an exploded perspective view of the push ³⁵button switch assembly of FIG. 1 with contact modules and panel mounting parts removed;

? FIG. 5 is a rear view of a push button stem for use in the push button switch assembly of FIG. 1;

FIG. 6 is an end view of a push button cam for use ⁴⁰in the push button switch assembly of FIG. 1;

FIG. 7 is a side elevational view of the push button cam of FIG. 6;

FIG. 8 is a cross sectional view taken along the line 8—8 of FIG. 6; ' &lt;^?'.· ⁴⁵

FIG. 9 is a cross sectional view taken along the line 9—9 of FIG. 6;

FIG. 10 is a rear elevational view of a contact module for use in the push button switch assembly of FIG. 1;

FIG. 11 is a front elevational view of the contact ‘’θ module of FIG. 10;

FIG. 12 is an enlarged cross sectional view taken along the line 12—12 of FIG. 11 with a contact operator partially cut-away;

FIG. 13 is an enlarged cross sectional view taken ⁵along the line 13-13 of FIG. 11;

FIG. 14 is an exploded perspective view of the contact module of FIGS. 10-13;

FIG. 15 is a front elevational view labeled A and a pair of fragmentary views labeled B and C showing embodiments of the contact operator for the contact moduleofFIGS. 10-13;

FIG. 16 is a side elevational view, similar to FIG. 1, of an illuminated push button switch assembly with a light module and a single contact module attached;

FIG. 17 is a rear elevational view of the illuminated push button switch assembly of FIG. 16;

,501

FIG. 18 is an enlarged cross sectional view taken generally along the line 18—18 of FIG. 17, but partially in elevation;

FIG. 19 is an exploded perspective view of a light assembly for use in the illuminated push button switch of FIGS. 16-18;

FIG. 20 is a side elevational view of a selector switch assembly made in accordance with the present invention and mounted on a panel;

FIG. 21 is a partially cut-away rear elevational view of the selector switch assembly of FIG. 20 with contact modules and a selector switch cam removed;

FIG. 22 is an enlarged cross-sectional view of the selector switch assembly of FIG. 20 taken along the line 22—22 of FIG. 21;

FIG. 23 is an exploded perspective view of the selector switch assembly of FIG. 20 with contact modules and panel mounting parts removed and a selector switch knob locking ring partially cut away;

. FIG. 24 is a rear end view of a selector switch stem for use in the selector switch assembly of FIG. 20;

FIG. 25 is a rear end view of an alternate embodiment of the selector switch stem of FIG. 24 with a selector switch cam assembly attached;

FIG. 26 is a partially sectioned rear elevational view of the selector switch assembly , similar to FIG. 21, with a retainer, stop ring and index pin spring thereof removed;

FIG. 27 is a rear elevational view of a cam portion for Use in the selector switch assembly of FIG. 20;

FIG. 28 is a rear elevational view of another cam portion for use in the selector switch assembly of FIG. 20;

FlG. 29 is a diagrammatic representation illustrating camming operation of the selector switch assembly of FIG. 20;

FIG. 30 is another diagrammatic representation illustrating camming operation of the selector switch assembly of FIG. 20;

FIG. 31 is a side elevational view of the selector, switch assembly‘of FIG. 20 provided with a double stacked cam assembly;

FIG. 32 is a cross-sectional view of a momentary selector switch assembly, made in accordance with the present invention, taken generally along the line 32—32 of FIG. 33;

FIG. 33 is a cross-sectional view of the momentary selector switch assembly taken generally along the line 33—33 in FIG. 32;

FIG. 34 is a rear elevational view of a return spring for use in the momentary selector switch assembly of FIG. 32;

FIG. 35 is a rear elevational view of a return spring holder for use in the momentary selector switch assembly of FIG. 32;

FIG. 36 is a side elevational view of the return spring holder of FIG. 35;

FIG. 37 is a partially cut-away side elevational view of a momentary-maintained switch made in accordance with the present invention and with contact modules removed; and,

FIG. 38 is a cross-sectional view of an illuminated selector switch assembly similar to FIG. 22.

An embodiment of the switch assembly of the present invention is illustrated in FIGS. 1-4. FIG. 1 shows a push button switch assembly 11 Which is mounted on a panel 12 with a push button operator 14 extending forwardly of the panel 12.

3,740,501

An external oil seal, preferably in the form of a ring shaped rubber oil sealing gasket 15, is fitted around a body 16 of the push button switch assembly 11 and positioned to abut the rear surface of the panel 12. To accommodate differences in panel thickness, an appropriate number of metal spacers 17 may be placed behind, and in abutting relation with, the oil sealing gasket 15. A lock ring 19 holds the push button switch assembly on the panel 12 by threadably engaging external threads 20 (see FIG. 3) located at the forward end of the body 16. A metallic locating ring 21 may be interposed between the lock ring 19 and the panel 12, in a manner well known in the art, to prevent rotation of the push button switch assembly 11 with respect to the panel 12. If desired, the locating ring 21 may be provided with an enlarged portion and thus also function as a legend plate.

One or more contact modules 22 may be attached to the body 16 at any or all of the locations which are provided and identified by the Roman numerals I, II, III, IV on the body 16, as can be seen in FIG. 2. The construction, functional details and mode of attachment of the contact module 22 will be subsequently disclosed in detail.

The push button switch assembly 11 is best described with reference to FIGS. 3 and 4 and comprises the push button 14, the body 16, an internal oil seal 24, an actuator means such as a push button stem 25, a return spring 26, which is preferably in the form of a helical compression spring, a retainer 27, and a push button cam 29.

The push button 14 may be molded of any suitable material, such as polycarbonate resin, and may have any suitable desired shape, size or appearance.

The body 16 (FIGS. 2-4) is preferably die cast of a zinc alloy, or a similarly suitable material. An internal wall portion 30 defines a substantially cylindrical opening therethrough and a narrow forward portion of the opening defines a rearwardly directed shoulder 30α. A plurality of keyways 31 are formed in the wall portion 30 and are axially aligned with the opening. The keyways 31 terminate in a widened portion toward the rear end portion of the body 16 to expose surfaces 32 for use when the body 16 is incorporated in a selector switch, as will be described in detail, and surfaces 33 for supporting the retainer 27.

A plurality of arcuate grooves 34 (FIG. 2) are formed in a rear surface 35 of the body 16 and are spaced circumferentially of the cylindrical opening. A plurality of internally threaded openings 36, preferably one more than the number of arcuate grooves 34, are drilled in the rear surface 36 of the body 16. In the preferred embodiment, each of four threaded openings 36 is paired with a corresponding arcuate groove 34 to accommodate attachment of one of the contact modules 22. A fifth threaded opening, indicated as 36α, is provided to accommodate attachment of a light module in a manner to be later described with reference to FIG. 17.

The front end portion of the internal wall portion 30 has a circumferential groove 37 formed therein (FIG. 4). The circumferential groove 37 is adapted to house the internal oil seal 24 and hold it against axial motion during switch operation. The internal oil seal 24 is formed of a resilient material and preferably has a substantially Y-shaped cross section, as is best illustrated in FIG. 3.

The push button stem 25 is molded of a suitable material such as polyphenylene oxide and is molded or machined to provide an external thread on a forward end portion 38 for attachment of the push button 14 by engagement with a corresponding internal thread 39 therein (see FIG. 3). A circumferentially enlarged portion 40 of the push button stem 25 interacts with the shoulder 30a of the body 16 to serve as a forward stop for the push button stem 25 and has an outwardly facing circumferential surface which serves as a forward bearing surface 41 to interact with the internal wall portion 30 of the body 16 during switch operation. A plurality of keys 42 are formed on the forward bearing surface 41. The keys 42 are preferably equal in number to and aligned with the keyways 31 in the body 16 and are held therein to prevent rotational motion of the push button stem 25 during its longitudinal motion within the body 16. The rear of the portion 40 forms a forward spring seat 44 (see FIG. 3).

The central portion of the push button stem 25 is preferably of circular cross section and has a widened forward portion defining a rearwardly directed shoulder 45 adjacent a rear bearing surface 46 on the central portion of the push button stem 25. The push button stem 25 preferably tapers inwardly toward a rear end portion which functions as a cam carrier portion 47 and is best illustrated in FIG. 5. The cam carrier portion 47 has a cross section which is substantially in the form of a square having foreshortened corners. In the preferred embodiment, two opposite corners, indicated at 49, are foreshortened equally. A third corner 50 is shortened by an amount greater than the corners 49 and a fourth corner 51 has a forward portion 51α which is shortened by substantially the same amount as the corners 49 and a rear portion 516 which is shortened by substantially the same amount as the corner 50. A rearwardly directed shoulder 51c is thus formed in the corner 51.

The retainer 27 is die cast, preferably from a material similar to that of the body 16, in the form of a ring with an outer dimension enabling it to cover the rear end portion of the cylindrical opening through the body 16. A tab 52 on the retainer 27 is adapted to fit within a complementary recess 54 formed in the rear surface 35 of the body 16 (see FIG. 2). The inner portion of the retainer 27 is preferably elongated in a direction corresponding to the longitudinal axis of the body 16 to provide an annular bearing surface 55 for interacting with the rear bearing surface 46 on the push button stem 25. A circumferential groove may be provided in the forwardly facing surface of the retainer 27 to serve as a rear spring seat 56.

The push button cam 29 is illustrated in FIGS. 6-9 and is molded of a suitable material, such as fluorocarbon filled acetal resin, and has an appropriate external shape for performance of the desired switching program. It should be understood that a plurality of different externally shaped cams 29 may be provided.

In the preferred embodiment, each cam 29 must be able to perform two switching programs and must accordingly have two, and only two, distinct mounting positions. Therefore, the internal form of the cam 29 is made to cooperate with the cam carrier portion 47 of the push button stem 25 to provide the two required distinct mounting orientations. The cam 29 has an opening 57 extending longitudinally therethrough and formed substantially in the shape of the cam carrier portion 47 of the push button stem 25. Two opposite

501

The return spring 26 is then placed within the body 16 and around the push button stem 25 so that its forward end portion is seated within the forward spring seat 44. The return spring 26, in its uncompressed state, extends a short distance beyond the rear of the body portion 16.

The retainer 27 is placed over the cylindrical opening at the rear surface 35 of the body 16 with the rear spring seat 56 oriented in a forward direction and the tab 52 aligned with and received in the recess 54. The rear spring seat engages the rear end of the return spring 26 urging it forward into a partially compressed configuration. The retainer 27 is then staked in position or affixed to the body 16 by other suitable means.

A desired one of the push button cams 29 is then placed on the cam carrier portion 47 of the push button stem 25 and the push button 14 is connected to the push button stem 25 by engaging the internal threads 39 in the push button 14 with the threads on the forward end portion 38 of the stem. It should be noted, however, that, if the push button 14 is large in size, it may be necessary to connect the push button 14 after installation of the push button switch assembly 11 on the panel 12.

In the preferred embodiment, an identification mark 65 (FIG. 6) is formed on the ledge 61 at the end face 62 of the push button cam 29, indicating the switching program performed by the cam when seated with that end face 62 facing rearwardly of the push button assembly 11. Since the indexing mark 64 on the push button stem 25 is positioned at the fourth corner 51, alignment of the identification mark 65 on the push button cam 29 with the indexing mark 64 on the push button stem properly orients the parts to facilitate rapid and ³³ easy cam seating.

When the push button assembly 11 is held in place, as by affixing it to a panel 12 in the manner shown in FIG. 1, and the push button 14 is biased, as by finger pressure, in a direction along the longitudinal axis of ⁴⁰ the push button stem 25, the combination of push button 14, push button stem 25 and push button cam 29 is moved toward the rear of the push button switch assembly 11. The interaction of the forward bearing surface 41 and the rear bearing surface 46 of the push but⁴⁵ ton stem 25 with the internal wall portion 30 of the body 16 and the bearing surface 55 of the retainer 27, respectively, permits substantially wobble-free longitudinal motion of the push button stem 25 while interaction of the keys 42 within the keyways 31 prevents rota^υ tion. The shoulder 45 serves as a stop for the push button stem 25 by interfering with the forward face of the retainer 27 to limit rearward travel of the push button stem 25.

₅₅ Rearward motion of the push button stem 25 causes the forward spring seat 44 to move toward the rear spring seat 56 thereby further compressing the return spring 26 so that, upon release of the push button 14, the push button stem 25 and the attached cam 29 and ₆θ push button 14 are biased toward the forward end of the push button assembly 11.

Referring now to FIGS. 10-15, a preferred contact module 22 is illustrated having a base 66 and a cover 67 molded of suitable materials such as polycarbonate ₆₅ resin. The forward end portion 69 of the base 66 has an arcuate projecting tongue 70 molded thereon. The tongue 70 is formed to fit within one of the arcuate grooves 34 on the rear surface 35 of the body 16. An

3,740, ' 5 corners 59 of the cam 29 have a size and shape which allows them to be fitted over the respective corners 49 on the cam carrier portion 47. The other two corners 60 have substantially the same dimensions as the corners 59 over most of their lengths but terminate at op- 5 posite end portions in inwardly projecting ledges 61 which foreshorten the corners 60 by an amount corresponding to the foreshortening of the third corner 50 and of the rear portion 51b on the fourth corner 51 on the cam carrier portion 47 of the push button stem 25. 10

With this construction, the cam 29 can be seated on the cam carrier portion 47 with either end face 62 in a forward direction. However, in each of these orientations, the push button cam 29 can be seated on the cam carrier portion 47 in only one position. In either orien- 15 tation of the cam 29, one of the ledges 61 will be located at the forward end face and the other ledge 61 will be at the rear. To seat the cam 29, the ledges 61 must be fitted over the more greatly foreshortened corners 50 and 51 of the cam carrier portion 47. If the cor- 20 ner 60 having the forward facing ledge 61 is placed over the cam carrier corner 51, the passage of the ledge 61 will be blocked by the shoulder 51c so that the cam cannot be seated. Therefore, the corner 60 having the forward facing ledge 61 must be positioned over the 25 cam carrier comer 50. This enables the cam 29 to be fully and properly seated since the foreshortened rear portion 51£&gt; of the fourth corner 51 of the cam carrier portion 47 will accommodate the rear facing ledge 61.

If the cam 29 is removed and rotated 180° around an ³⁰axis through the corners 59 in FIG. 6, the positions of the ledges 61 are reversed so that the push button cam 29 can be seated, in the same manner as hereinbefore described, in its second orientation. Thus two and only two camming programs may be provided with one cam 29.

Cooperating detent means may be provided in the form of bosses 63α on the cam carrier portion 47 of the push button stem 25 adapted to interfere with corresponding shoulders 63b on the push button cam 29. This interference fit holds the cam 29 in place during operation of the push button switch assembly 11 and provides snap-action mounting and removal for the cam.

Assembly of the push button switch assembly 11 is best described with reference to FIGS. 3 and 4. The internal oil seal 24 must first be fitted into the circumferential groove 37 provided for that purpose in the body 16. The push button Stem 25 can then be inserted into the rear of the cylindrical opening in the body 16 so that the keys 42 on the forward bearing surface 41 of the push button stem 25 ride within the keyways 31 on the internal wall portion 30 of the body 16.

The correspondence of the keys 42 and key ways 31 allows the push button stem 25 to be inserted in any of a number of different orientations. However, to provide reproduceability for the switching programs which can be performed by each cam, it is necessary that the push button stem 25 be inserted in a single predetermined orientation. For this purpose, an indexing mark 64 (FIGS. 2 and 5) which may be in a form such as the arrow shown, is preferably provided on the push button stem 25. In the preferred embodiment, proper orientation of the push button stem 25 is achieved by positioning the indexing mark 64 halfway between Roman numerals I and II (see FIG. 2) on the rear surface 35 of the body 16.

501 vered and bifurcated to improve its electrical characteristics and minimize contact damage.

The contact operator 87, also shown in FIG. 15A, is preferably molded of an insulating material, such as a 5 thermoplastic resin, and has a central portion 100 which widens toward one end portion to terminate in projecting leg portions 101 which have parallel guide surfaces 102 externally thereof. The guide surfaces 102 interact with corresponding surfaces 104 (FIG. 12) in 10 the torsion spring chamber 79 of the base 66 to maintain lateral alignment of the contact operator 87 during operation of the contact module 22. An indicator stop portion 105 in the form of a web is preferably formed between the leg portions 101 for interaction with the 15 indicator 86.

The contact operator 87 widens from the central portion 100 toward the other end portion thereby defining contact spring camming surfaces 106 which interact with the respective bosses 97 on the contact spring por20 tions 91 of the contact assembly 85 to effect movement of the contact spring portion 96 during operation of the contact module 22 thereby to open and close the contacts 99. Early or late opening and closing of the contacts 99 may be provided by forming the contact opera25 tor 87 with the camming surfaces 106 shifted toward or away from the central portion 100. An early opening, late closing contact operator 87α can be formed by shifting the camming surfaces toward the central portion 100, as shown by the camming surface 106α in FIG. 15B. A late opening, early closing contact operator 87i&gt; can be formed by shifting the camming surfaces away from the central portion 100, as shown by the camming surface 106Z&gt; in FIG. 15C. The time differential between operation of an early or late opening con— tact module and a standard contact module is dependent upon the distance between the relative positions of the camming surfaces 106.

Each camming surface 106 terminates with a shoulder 107 which interacts with an inner surface of the ⁴⁰ contact chamber 77 of the base 66 to provide a stop for the contact operator 87. A projecting nose portion 109 is formed at the end portion opposite the leg portions 101 and is provided with a cam surface 110 thereon. The shape of the cam surface 110 allows movement of the contact operator 87 along a longitudinal axis thereof upon interaction with a camming surface moving substantially perpendicular to the line of motion of the contact operator 87.

The indicator 86 (see FIG. 14) is formed of a suitable material, such as a fluorocarbon-fiber filled acetal, and has a projecting nose 111 at one end portion. The other end portion 112 has suitable indicia such as a contact condition indicating mark 114 hot stamped or otherwise visibly displayed thereon.

For assembly of the contact module 22, each contact assembly 85 is positioned with the terminal portion 90 held within a terminal holding chamber 81 in the cover 67. Each terminal portion 90 extends through a narrow opening 115 in the cover 67 for holding the contact assembly 85 while allowing external electrical connection of the terminal portion 90. When the contact assemblies 85 are positioned in the cover 67, the bosses 97 and contacts 99 on the contact spring portion 91 are inwardly facing and the contacts 99 are abutting each other.

The indicator 86 is placed in indicator chamber 80 of the cover 67 with the projecting nose 111 facing in a

3,740 extended edge 71 of the forward end portion 69 is molded or drilled to provide an opening 72 therethrough which is adapted for holding a threaded fastener such as a screw 74. If desired, an internal peripheral lip 75 (FIG. 13) may be formed at the rear end portion of the opening 72 and threaded to allow passage of the screw 74 which is provided with an unthreaded shank portion 76 of reduced diameter. This allows the screw 74 to be threaded through the lip 75 so that the shank portion 76 is within the lip 75 and free to move longitudinally within the opening 72 without being removable. In this manner, the screw 74 becomes a “captive screw”.

The opening 72 is located on the extended edge 71 in a position which will permit alignment and threaded attachment of the screw 74 in the corresponding opening 36 in the body portion 16 when the tongue 70 is in the groove 34. The combination of tongue in groove and threaded attachment locks the contact module 22 onto the body 16 and keeps it aligned for proper switch operation.

The base 66 and cover 67 have a plurality of internal chambers formed therein. The base 66 (see FIG. 12) has a contact chamber 77 and a torsion spring chamber 79. The cover 67 (FIG. 14) has an indicator chamber 80 and two terminal holding chambers 81 opening to the rear of the cover 67 (see FIG. 13). The base 66 and cover 67 may be attached to each other by cementing or ultrasonic welding or any other desired method. Up- jq standing ridges 82 may be provided on the cover 67 to cooperate with corresponding recesses 84 in the base 66 to aid in alignment and attachment of the cover 67 to the base 66.

The contact module 22 (FIG. 14) includes a pair of contact assemblies 85, an indicator 86, a contact operator 87 and a torsion spring 89.

Each contact assembly 85 has a terminal portion 90 and a contact spring portion 91 and, since the contact assemblies 85 are identical, only one will be described. The terminal portion 90 is preferably stamped from an electrically conductive material such as brass with a rear end portion preferably formed in the shape of a push-on type solderless terminal. Other desired terminal types may, of course, be utilized in a manner well 45 known in the art.

The contact spring portion 91 is preferably stamped from an electrically conductive material, such as beryllium cbpper, arid formed, as best shown in FIG. 13, to have a substantially planar rear end portion 92 with a ⁵⁰pair of openings 94 therein (FIG. 14) corresponding to a pair of alignment studs 95 (FIG. 13) provided on the terminal portion 90. When the contact spring portion 91 is positioned against the terminal portion 90 with the alignment studs 95 in the corresponding openings 94, the contact assembly is properly aligned and may be permanently attached, preferably by welding or brazing.

A central portion. 96 of the contact spring portion 91 is offset in a direction away from the terminal portion 90 and is aligned in a plane substantially parallel to that of the rear end portion 92. A boss 97, protruding away from the terminal portion 90, is formed in the central portion 96 for interaction with the contact operator 87. The forward end portion of the contact spring portion 91 is further offset away from the terminal portion 90 and bowed to define a contact 99, which may be sil3,740,501 through the opening 116 and displays the closed condition of the contacts 99.

During switching operation of the contact module 22 on the push button switch assembly 11, camming of the projecting nose portion 109 of the contact operator 87 is performed by the push button cam 29 (FIGS. 6-9). The push button cam 29 preferably has four external camming surfaces 122. Each camming surface 122 has an outer portion 124 coinciding with the outer surface of the push button cam 29 adjacent one end face 62 and slopes inwardly to a recessed portion 125 adjacent the other end face 62.

Mounting the push button cam 29 on the push button stem 25 when a contact module 22 is affixed at the rear surface 35 of the body 16 positions the rear end portion of the camming surface 122 for operative interaction with the projecting nose portion 109 of the contact operator 87. When the push button 14 is depressed, the forward end portion of the camming surface 122 controls the contact operator 87.

Thus, the identity of the rear end portion of the camming surface 122 determines whether the contacts 99 in the corresponding contact module 22 will be normally open or normally closed. Normally closed contacts result when the rear end portion of the camming surface 122 is the recessed portion 125. In this configuration, the nose portion 109 of the contact operator 87 projects into the recess so that the central portion 100 of the contact operator 87 is between the bosses 97 and the contacts 99 are closed. Operation of the push button switch assembly 11 by depressing the push button 14 shifts the push button cam 29 in a rearward direction thus moving the outer portion 124 of the camming surface 122 into alignment with the projecting nose 35 portion 109 of the contact operator 87. The camming surface 122 outwardly biases the contact operator 87 and thereby causes the contact spring camming surfaces 106 to open the contacts 99 in the manner previously described herein. Release of the push button 14 ⁴⁰ allows the contacts 99 to reacquire their normally closed configuration.

If the rear end portion of the camming surface 122 is the outer portion 124, the projecting nose portion 106 of the contact operator 87 is biased into the con4$ tact module 22 so that, as hereinbefore indicated, the contacts 99 are normally open. Depressing the push button 14 shifts the recessed portion 125 into alignment with the projecting nose portion 109 and allows the contacts 99 to close. Release of the push button 14 reestablishes the normally open configuration of the contacts 99.

In the preferred embodiment of the push button switch assembly 11, four camming surfaces 122 are provided on each push button cam 29, corresponding ³ to the maximum number of contact modules 22 which may be used. With a particular cam 29, from zero to four normally closed contacts may be provided by orienting that number of camming surfaces 122 with the recessed portion 125 as the rear end portion. Oppositely oriented camming surfaces 122 would produce normally open contacts. If desired, the identification mark 65 on the push button cam 29 (see FIG. 6) may be a number designating the number of normally closed contacts provided by that particular cam. It should be readily apparent that, since each push button cam 29 may be mounted on the push button stem 25 in either of two orientations, reversed front to back, those cam9 generally forward direction and the end portion 112 facing generally rear so that the contact indicating mark 114 may be aligned with an opening 116 (see FIGS. 1 and 10) in a rear end wall of the indicator chamber 80 to indicate the operative condition of the 5 contacts 99. For example, indicia such as a standard contact symbol 117, as shown in FIG. 10, may be hot stamped or otherwise displayed at the opening 116. The contact indicating mark 114 is then preferably in the form of a diagonal line visible through the opening 10 116 whenever the contacts 99 are closed, forming the standard electrical symbol designating a pair of closed contacts. When the contacts 99 are open, the contact indicating mark is moved out of alignment with the opening 116 and therefore not visible so that the stan- 15 dard electrical symbol for a pair of open contacts is seen. In this manner, a readily understandable means for indicating the electrical condition of the contacts 99 is provided which may easily be seen by looking at the cover 67 of the contact module 22. 20

The contact operator 87 is then positioned between the contact assemblies 85 adjacent the bosses 97 on the contact spring portions 91. With the central portion 100 between the bosses 97, the projecting nose portion 109 of the contact operator 87 extends through an ap- 25 erture 119 (FIG. 12) in a side wall portion of the base 66. The width of the central portion 100 is sufficiently small to enable the contacts 99 to remain in abutment.

The torsion spring 89 is held within the torsion spring chamber 79 in the base 66. One leg 120 of the torsion ³θ spring 89 has an end portion 121 which is bent convexly outward to abut the indicator stop portion 105 of the contact operator 87 and the projecting nose 111 of the indicator 86. This biases the projecting nose 111 toward a position between the leg portions 101 and toward the rear of the indicator stop portion 105 of the contact operator 87. When the indicator 86 is in this position, the contact indicating mark 114 is visible through the opening 116 in the cover 67 and thus displays the closed condition of the contacts 99.

If the projecting nose portion 109 of the contact operator 87 is laterally biased, as by a push button cam 29, the contact operator 87 moves in a direction toward the torsion spring 89. The contact spring camming surfaces 106 apply outward forces to the respective bosses 97 on the respective contact spring portions 91 of the contact assembly 85. The interaction of the contact spring camming surfaces 106 and the bosses 97 cause the contact spring portions 91 to separate, thereby opening the contacts 99. The contact operator 87 drives the projecting nose 111 of the indicator 86 against the biasing force of the torsion spring 89. The resulting rotational motion of the indicator 86 moves the contact indicating mark 114 away from the opening 116 to display the open condition of the contacts 99.

When the projecting nose portion 109 of the contact operator 87 is released, the contact spring portions 91 apply an inward force through the bosses 97 to the contact spring camming surfaces 106. This drives the contact operator 87 in a direction away from the torsion spring 89 to the position in which the central portion 100 of the contact operator 87 is between the bosses 97 and the contacts 99 close. The torsion spring 89 biases the projecting nose 111 of the indicator 86 and causes it to follow the contact operator 87. The resulting rotational motion of the indicator 86 places the contact indicating mark 114 in a position in which it is visible

3,740,501 ming surfaces 122 which, in one orientation, produce normally closed contacts would, in the opposite orientation, produce normally open contacts. Those camming surfaces 122 which, in the first orientation, produced normally open contacts would, when reversed, produce normally closed contacts. Thus a push button cam 29 producing four normally closed contacts in one orientation, such as that illustrated in FIG. 4, would produce no normally closed contacts in its other orientation. A cam producing three normally closed contacts in one orientation, (not illustrated) would produce one normally closed contact in its other orientation. A cam producing two normally closed contacts, such as the one illustrated in FIGS. 6-9, would do so in either orientation. In this manner, all possible switching combinations can be provided for the push button switch assembly 11 with only three different push button cams 29.

An illuminated push button switch assembly 111 is illustrated in FIGS. 16-18. Its construction is similar to that of the push button switch assembly 11, as can be seen by comparing FIGS. 16 and 18 with FIGS. 1 and 3 respectively. Parts common to both embodiments have been similarly numbered.

The push button stem 25 has a longitudinal opening 126 therethrough (see FIG. 3) with a narrow portion 127 defining a rearwardly directed shoulder 129. The opening 126 is adapted to receive a lamp 130 (see FIG. 19), a pair of lamp terminals 131 and a lamp terminal holder 132. The lamp 130 may be of either the incandescent or neon type and is preferably substantially cylindrical in shape having an insulating base 134 and a pair of lamp contacts 135 located on opposite sides of the lamp 130.

Each lamp terminal 131 is preferably stamped and formed of a conductive material, such as brass, and has a substantially planar forward portion 136 with an outwardly bent end portion 137 to facilitate insertion of lamp 130. Each forward portion 136 may be provided with an enlarged portion 139 bent to conform to the shape of the lamp contact 135. Each forward portion 136 is outwardly displaced from an attachment portion 140 which has an outwardly bent attachment tang 141 for interaction with the lamp terminal holder 132. Rear end portions 142 of the lamp terminals 131 are inwardly bent to provide respective contact surfaces 144.

The lamp terminal holder 132 is molded of a suitable insulating material, such as polycarbonate resin, and is substantially cylindrical in shape with a tongue 145 extending essentially rearwardly therefrom. An enlarged central portion 146 of the lamp terminal holder 132 defines a forwardly directed shoulder 147. A pair of alignment notches 149 are preferably formed on opposite sides of the forward end portion of the holder. A pair of longitudinal openings 150 are provided in the lamp terminal holder 132 to accommodate the attachment portions 140 of the lamp terminals 131 (see FIG. 18). An outer wall portion 151 of each opening 150 has a rearwardly directed shoulder 152 formed therein for interaction with one of the attachment tangs 141 to secure the lamp terminal 131. Side portions 154 of the tongue 145 are broadened to enhance the strength of the tongue 145.

The lamp terminal holder 132 is inserted from the rear through the longitudinal opening 126 in the push button stem 25, with the tongue 145 rearwardly extended, until the shoulder 147 of the holder 132 abuts the shoulder 129 in the push button stem 25. The holder 132 must be oriented to align the alignment notches 149 with corresponding alignment bosses 155 (see FIG. 5) molded in the narrow portion 127 of the longitudinal opening 126 in the push button stem 25. Interaction of the alignment notches 149 and alignment bosses 155 fixes the orientation of the lamp terminal holder 132 within the push button stem 25 and prevents rotation of the holder 132.

After the lamp terminal holder 132 has been positioned, the lamp terminals 131 are inserted through the forward end of the opening 126 in the push button stem 25. The rear end portions 142 of the lamp terminals 131 are inserted in the respective openings 150 in the holder 132 until the attachment tangs 141 on the attachment portions 140 are in interlocking relation with the respective shoulders 152 (FIG. 18). After both lamp terminals 131 are in place, the lamp 130 may be inserted through the front of the push button stem 25. In this manner access may be had to the lamp 130 so that it may be inserted, removed or changed while the push button switch assembly is in place on a panel 12 simply by removing the push button 14 to expose the forward end portion 38 of the push button stem 25. It should be clear that, for light from the lamp 30 to be visible, the push button 14 must be formed of a transluscent or transparent material.

Electrical power for operating the lamp 130 is preferably supplied through a hollow light module 156 (FIGS. 16-18) having a base 157 and cover 159 (FIG. 16) molded of a suitable insulating material such as polycarbonate resin. The light module 156 has a size which enables it to be mounted on the back surface 35 of the body 16, utilizing the same space required to mount two of the contact modules 22. Accordingly, two tongues (not shown), each similar to the tongue 70 on the base 66 of the contact module 22, are provided on the base 157 of the light module 156 and are positioned for insertion in two adjacent ones of the arcuate grooves 34. In the preferred embodiment, the light module 156 is attached to the rear surface 35 of the body 16 at the positions indicated by Roman numerals III and IV (see FIG. 2). Therefore, the threaded opening 36α must be located adjacent the arcuate groove 34 at Roman numeral III opposite the threaded opening 36 nearest Roman numeral IV to accommodate a pair of threaded fasteners, such as captive screws 160, received in openings in the base 157 of the light module 156. The combination of tongue in groove and threaded attachment releasably attaches the base 157 to the body 16. The cover 159 is ultrasonically welded, or otherwise suitably attached, to the base 157.

A pair of input terminals 161 (FIG. 17) which may be of the push-on solderless type, are provided in the cover 159 for external attachment to a source of electric power. A pair of output terminals 162 (FIG. 18) are provided in the base 157 to supply operating power to the lamp 130. The input terminals 161 may be directly connected to the respective output terminals 162 or may be connected through a resistor or a transformer contained within the module 156 in a manner well known in the art. These means for connecting the terminals 161-162 are contained in a cavity (not shown) within the light module 156. The output terminals 162 are held in alignment with the push button stem 25 and are so positioned that the contact surfaces 144 on the rear end portions 142 of the lamp terminals

3,14

131 make a sliding electrical contact with the output terminals 162. The light module 156 and lamp terminals 131 form a power means for the lamp 130. Proper orientation of the lamp terminals 131 in the push bottom stem 25, the push button stem 25 in the body 16, and the light module 156 on the body 16 insure a proper alignment and interaction of the contact surfaces 144 and the output terminals 162. As can be seen in FIG. 18, sliding contact is maintained between each contact surface 144 and its corresponding output terminal 162 when the push button 14 is extended or depressed so that the lamp 130 may remain illuminated during all operations of the illuminated push button switch assembly 111. If desired, the light module 156 may be powered through one of the contact modules 22 so that it will be illuminated in only one of the positions of the push button 14. Also, the illuminated push button switch assembly 111 may utilize one normally open and one normally closed contact module 22 to form a push-to-test unit in a manner well known in the art.

A selector switch embodiment of the present invention is illustrated in FIGS. 20-23 wherein component parts which are common to both the selector switch and push button switch assemblies are given the same identifying numbers used in describing the push button switch assembly 11.

Referring now to FIG. 20, a selector switch assembly 164 is shown mounted on a panel 12 and is oriented to have a selector switch knob 165 extended forwardly of the panel 12.

A lock ring 166 holds the selector switch assembly 164 on the panel 12 by threadably engaging the external threads 20 located at the forward end portion of the body 16.

Contact modules 22 may be attached to the body 16 at any or all of the locations indicated by the Roman numerals I, II, III, TV on the body 16 (see FIG. 21).

The selector switch assembly 164, as best shown in FIGS. 22 and 23, comprises the selector switch knob 165, a selector switch knob locking ring 167, the body 16, the internal oil seal 23, a selector switch stem 168, a pair of index pins 169, an index pin spring 170, which is preferably in the from of a helical compression spring, a stop ring 171, the retainer 27, and a selector switch cam assembly 172.

The selector switch knob 165 is preferably molded of a suitable material, such as polycarbonate resin, and may have any desired shape and markings and has a forward handle portion 174. A rear end portion 175 is preferably cylindrical in shape to facilitate rotation of the selector switch knob 165 within the forward end portion of the body 16. A substantially cylindrical circumferential surface 176 extends rearwardly from the ₅₅forward portion 174 and preferably has a plurality of attachment tabs 177 formed at a rear end portion thereof.

The selector switch knob locking ring 167 may be machine formed of aluminum or other suitable material ₆θ and has an internally threaded rear end portion 179 for attachment to the external threads 20 at the forward end portion of the body 16. The forward end portion of the selector switch knob locking ring 167 has an internal circumferential groove 180 therein to accommo- ₆₅date securement of the selector switch knob 165 through snap fitting of the attachment tabs 177 on the selector switch knob 165 into the internal circumferen0,501 tial groove 180 in the locking ring 167. The relative dimensions of the tabs 177 and groove 180 should allow rotational movement of the knob 165 within the locking ring 167 so that the selector switch knob 165 may 5 be operatively secured to the body 16.

The selector switch stem 168 is preferably molded of polyphenylene oxide, or another suitable material, and has a plurality of longitudinal grooves 181 formed in a forward end portion thereof. The grooves 181 interact 10 with splines 182 formed on an inner surface 184 of the selector switch knob 165 (see FIG. 22) to engage the selector switch knob 165 and stem 168 during operational rotational motion within the body 16. The combination of the spline in groove alignment and the snap 15 fitting relation of the selector switch knob 165 and locking ring 167 permit ease in alignment and attachment of the selector switch knob 165, as should be readily apparent to those skilled in the art.

An enlarged portion 185 of the selector switch stem 20 168 defines a forward bearing surface 186 which interacts with the shoulder 30a in the body 16 (FIG. 22) and a circumferential outer bearing surface 187 which interacts with the internal wall portion 30 of the body 16 during rotational motion of the selector switch stem 25 168. A rearwardly facing side of the enlarged portion 185 serves as a cam surface 189 (see FIG. 24) having a plurality of oblique cam faces 190 alternately rising and falling in ratchet fashion around the cam surface 189 thereby forming peaks 191 with V-shaped depres³θ sions 192 therebetween. The cam surface 189 cooperates with the index pins 169 and the index pin spring 170 to form a detent means operating in a manner to be hereinafter described. The maximum number of positions which may be provided by a 360° rotation of the ³⁵ selector switch stem 168 is equal to the number of Vshaped depressions 192 formed on the cam surface 189, as will be demonstrated. In one embodiment, eight position switching may be provided, as shown in FIG. 25, by spacing eight alternating peaks 191 and eight V⁴⁰ shaped depressions 192 around the cam surface 189.

Preferably, however, two opposite peaks 191 are eliminated as shown in FIG. 24, leaving substantially planar surfaces 194. This limits the detent means to providing four distinct positions for the selector switch assembly ⁴⁵ 164 but enables the switch to operate with maintained positions at one side of a rest position, wherein the selector switch stem 168 will remain until the selector switch knob 165 is moved to another position, and a momentary position at the other side of the central por^υ tion, from which the selector switch stem 168 will return to center unless the knob 165 is physically held in the momentary position of the switch. This embodiment of the selector switch assembly 164 will be subsequently described with reference to FIG. 37.

A central portion 195 of the selector switch stem 168 (FIG. 23) has an axially projecting tongue portion 196 extending rearwardly toward a cam attachment portion 197 of reduced diameter. The cam attachment portion 197 has a pair of concentric substantially cylindrical rings comprising an outer ring 199 (FIG. 24) and an inner ring 200 which preferably extends rearwardly of the outer ring 199. A plurality of axially aligned slots 201 are formed in the outer ring 199. In the preferred embodiment, four slots 201 are provided. Three of the slots 201 have substantially equal widths and one slot 201α is narrower than the other slots 201 to aid in alignment of the cam 172.

3,740,501

Each index pin 169 is preferably molded of a suitable material such as fluorocarbon filled acetal resin and has an outer portion 202 curved to substantially conform in shape to the internal wall portion 30 of the body 16 (FIG. 4). A substantially linear spline 204 is formed on 5 the outer portion 202 and aligned for travel in one of the keyways 31 in the body 16. A forward end portion 205 of each index pin 169 is shaped to fit within one of the V-shaped depressions 192 on the cam surface 189 of the selector switch stem 168 and projects inwardly to provide a biasing surface 206 for receiving the index pin spring 170.

The stop ring 171 is preferably stamped from steel and has a plurality of radially protruding ears 207 preferably equal in number to, and adapted to respectively fit in, the enlarged rear portions of the keyways 31 in the internal wall portion 30 of the body 15 (FIG. 4) in abutting relation with the surfaces 32. A substantially circular central opening 209 in the stop ring 171 has a diameter which will rotatably hold the cam attachment portion 197 of the selector switch stem 168 and has an arcuate recess 210 to accommodate the tongue portion 196 of the selector switch stem 168. As will become apparent, various stop rings 171 may be selected to provide desired operation.

Interaction of the tongue portion 196 and the arcuate recess 210 permits rotation of the selector switch stem 168. The width of the recess 210 determines the maximum amount of angular travel of the selector switch stem 168 and, accordingly, the number of positions available in a particular selector switch configuration. Since eight positions can be provided in one complete revolution, the selector switch stem 168 must rotate 45° between positions. Therefore, to provide two positions for the selector switch assembly 164, the arcuate dimension of the recess 210 must be 45° plus an amount equal to the angular width of the tongue portion 196 of the selector switch stem 168. A three position switch requires a 90° throw and each additional position requires that another 45° be added to the size of the recess 210. The maximum size of the recess 210 is needed for an eight position stop ring for which the size would be 315° in addition to the angular width of the tongue portion 196.

The selector switch cam assembly 172 is preferably molded of a suitable material such as fluorocarbon filled acetal resin and has a base portion 211 and a cam portion 212 which are separately formed and connected together by ultrasonic welding or other desired means. The base portion 211 is preferably substantially cylindrical in shape with a central opening 214 dimensioned to effect an interference fit with the inner ring 200 of the cam attachment portion 197 of the selector switch stem 168 and an outer dimension sufficient to effect an interference fit with the outer ring 199 (see FIG. 22). A plurality of bosses 216 are formed on the base portion 211 and are preferably aligned with, and equal in number to, the slots 201 in the outer ring 199 of the cam attachment portion 197 on the selector switch stem 168. In the preferred embodiment, three bosses 216 are aligned with, and dimensioned to fit respectively within, the three slots 201 and a fourth and narrower boss 216α is dimensioned to fit within the slot 201α in the outer ring 199 (see also FIG. 25). Because each boss 216 is too wide to fit within the narrower slot

201α, a one-way fit is provided for the base portion 211 of the selector switch cam assembly 172 with respect to the cam attachment portion 197 of the selector switch stem 168.

In assembling the selector switch assembly 164, the selector switch stem 168 is first placed into the rear of the opening in the body 16 with the longitudinal grooves 181 forwardly directed. The selector switch stem 168 does not have splines for riding in the keyways 31 in the body 16, as does the push button stem 25 (see FIG. 4), and is therefore free to rotate within the body 16.

The two index pins 169 are preferably inserted into the body 16 at locations 180° apart (see FIG. 26) for uniform biasing by the index pin spring 170. In the preferred embodiment, the index pins 169 are positioned 15 so that the splines 204 ride respectively in the key ways designated 31α in FIG. 26.

The index pin spring 170 is placed in the body 16 and positioned around the selector switch stem 168 with the forward end portion of the index pin spring 170 20 abutting the biasing surfaces 206 of the index pins 169.

The stop ring 171 is placed in the body 16 behind the index pin spring 170 and urged forwardly until the ears 207 are positioned within the enlarged rear portions of the keyways 31 in the internal wall portion 30 of the 25 body 16 abutting the surfaces 32. The stop ring 171 is then staked or otherwise locked in place.

The insertion of the stop ring 171 compresses the index pin spring 170 so that it applies a forwardly directed force which firmly biases the index pins 169 ³θ against the cam surface 189. The combination of index pins 169 and spring 170 and the cam surface 189 forms a detent means for maintained positions of the selector switch stem 168. When the selector switch stem 168 is rotated, as to change the condition of the contacts op35 erated thereby, one of the cam faces 190 is pressed against one face of the forward portion 205 of each index pin 169. Interaction of the spline 204 on the outer portion 202 of each index pin 169 and the keyway 31a in the body 16 holds each index pin 169 against lateral motion so that the cam faces 190 drive the index pins 169 in a rearward direction, opposing the biasing force applied by the index pin spring 170. When an index pin 169 has passed over a peak 191, it is driven in a forwardly direction by the index pin 45 spring 170 and is biased against the next cam face 190, thereby aiding the rotation of the selector switch stem 168 until the index pin 169 is positioned at the base of the next V-shaped depression 192. In this manner, the positions of the selector switch assembly 164 are dis^υ tinctly defined to facilitate ease and sureness of operation while changing positions and to releasably hold the selector switch stem 168 in each position.

Since uniformity and reproduceability are generally required in switching programs for contacts operated by a selector switch, the stop ring 171 must be positioned so that the arcuate recess 210 has a fixed, reproduceable position. Also, if a two, three or four position selector switch assembly 164 uses the preferred selector switch stem 168, with the planar surfaces 194 on the cam surface 189, the arcuate recess 210 must be placed so that the index pins 169 do not travel across the planar surfaces 194 while the selector switch stem 168 is rotating between maintained selector switch positions, since the planar surfaces 194 would not permit any distinction between the positions nor provide detent means for retention of the selector switch stem 168 in one of those positions. In the preferred embodiment

3,740,501 (see FIG. 21), the stop ring 171 is positioned so that the arcuate recess 210 fits over the tongue portion 196 of of the selector switch stem 168 while the tongue portion 196 is midway between Roman numerals I and II on the rear surface 35 of the body 16 and one end shoulder 217 of the arcuate recess 210 is aligned with Roman numeral II.

The retainer 27 is placed over the body 16 at the rear surface 35 with the tab 52 aligned with and held in the recess 54. The retainer 27 is staked in position or affixed by other suitable means. The selector switch cam assembly 172 is then attached to the cam attachment portion 197 of the selector switch stem 168 as previously described.

In this manner, two, three or four position or, with the alternate embodiment of the selector switch stem, up to eight position maintained switching operation may be provided for the selector switch assembly 164.

The cam portion 212 of the selector switch cam assembly 172 must be able to provide many different switching programs for up to four contact modules 22 in the two, three and four position standard modes of operation. Standard switching programs are well known in the art and generally require the use of many different molded cams and necessitate the stocking of a large variety of parts, sometimes as many as one type of cam for each program.

The preferred embodiment of the selector switch assembly 164 uses cam portions 212 having two distinct forms illustrated as cam portions 212α and 212h in FIGS. 27 and 28, respectively, to provide the desired switching programs. The selected cam portion 212 may be attached to the base portion 211 by ultrasonic welding or other desired means in any orientation required for a particular program.

The cam portion 212α (FIG. 27) has a pair of cam lobes 219 of substantially equal size and the cam portion 212# (FIG. 28) has a large cam lobe 220 and a small cam lobe 221. When the selector switch cam assembly 172 is assembled and in place on the selector switch stem 168, the cam lobes 219, 220 and 221 extend outwardly a sufficient distance to bias the contact operator 87 (FIG. 12) sufficiently to open the contacts 99. Those areas of the cam portion 212 between the cam lobes allow the contacts 99 to remain closed. Thus, for use in conjunction with an eight position switch, the cam portion 212α provides four closed positions (indicated by the symbols C in FIG. 27) and four open positions (indicated by the symbols 0 in FIG. 27). The cam portion 212&amp; (FIG. 28) provides six open positions and two closed positions. .

The versatility of the selector switch camming means of the present invention is illustrated in FIGS. 29 and 30 which show two different possible orientations in which the cam portion 212α may be utilized on identical selector switch assemblies 164 with the selector switch stem 168 having the same orientation in both figures. The Rornan numerals I, II, III and IV represent the positions of four sets of contacts for the purpose of this illustration.

The orientation of the cam portion, 212α shown in FIG. 29, provides for opening the contacts at positions I and IV while the contacts atpositions II and III remain closed. The orientation of the cam portion 212α shown in FIG. 30, which is obtained by shifting the cam portion 212 through an angle of 45° from the position shown in FIG. 29 before attaching it to the base portion

211, provides for opening the contacts at positions II and IV while the contacts at positions I and III remain closed.

Let us consider the cam portions 212α as illustrated in FIGS. 29 and 30 to be attached to a selector switch stem in the central position of a three position switching program. If the selector switch stem and attached cam portion 212α in FIG. 29 are shifted one switch position in the direction indicated by the arrow 222, the contacts at I close, the contacts at II open and the condition of the contacts at III and IV remains unchanged. It the cam portion 212α is shifted from the central position one switch position in the direction opposite that indicated by the arrow 222, the condition of the contacts at I and II remains unchanged while the contacts at III open and the contacts at IV close. It should be clear to those skilled in the art that a one position or 45° shift in the position of the cam portion 212α relative to the selector switch stem, as shown in FIG. 30, yields a totally distinct switching program.

In a similar manner, the cam portion 212h can be made to produce another two switching programs. Also, if either cam portion 212 is shifted by multiples of 90° from a particular orientation, the switching programs are correspondingly shifted to different sets of contacts. It should be noted here that although the foregoing discussion has been in the context of a three position selector switch, the same relationships also apply to two, four or more position switches.

It has been found that, although a limited number of switching program combinations can be provided by a single cam portion 212, selector switch cam assemblies 172 yielding substantially all generally used combinations of switching programs can be produced by stacking two cam portions 212 in various orientations relative to the base portion 211 as is shown in FIG. 31. When a double stacked selector switch cam assembly 172α is used, one, two or three contact modules 22 are operated by a forward cam portion 212/ and the remaining contact modules 22 are operated by a rear cam portion 212r. The forward cam portion 212/is attached to the base portion 211 and the rear cam portion 212r is attached to the forward cam portion 212/. In this manner, each cam portion 212 may be individually oriented relative to the base portion 211.

As has been hereinbefore indicated, the selector switch cam assembly 172 is dimensioned so that the cam portion 212 (the forward cam portion 212/in the case of the double stacked cam assembly 172α) is operatively aligned with the projecting nose portion 109 of the contact operator 87 in the contact module 22. Therefore, the operative dimensions of the contact module 22 must be altered to enable the rear cam portion 212r to operate the contact operator 82. It can be clearly seen, with reference to FIGS. 12 and 14, that the contact operator 87 is symmetrical about a longitudinal axis through the indicator stop portion 105 except for the nonsymmetrical projecting nose portion 109. Therefore, if contact operator 87 is rotated 180° around the longitudinal axis, its operation is not altered except that the projection nose portion 109 is shifted rearwardly to the position shown by a dashed line in FIG. 12 and indicated as 109α. This orientation of the contact operator 87 within a contact module 22 aligns the projecting nose 109α with the rear cam portion 212r (FIG. 31) for operative interaction therewith. Thus it should be readily apparent that by varying the

3,740,501 identity and orientation of the forward and rear cam portions 212 and by properly selecting which cam portion 212 will operate each contact module 22, substantially any desired switching program may be provided by only three different parts, the cam portions 212α and 212b and the base portion 211.

If desired, the selector switch assembly of the present invention may be adapted for use as a momentary switch, a configuration in which the selector switch stem 168 has a rest position and a position on one or both sides of the rest position from which spring return means returns the selector switch stem 168 to the rest position upon release of the selector switch knob 165.

The momentary selector switch assembly 164m, shown in FIGS. 32 and 33, is substantially similar to the maintained selector switch assembly 164 of FIGS. 22 and 23 except that certain additions and deletions of parts of parts have been made. The index pins 169 and index pin spring 170 are not used in the momentary selector switch assembly 164m. No detent means is required as no switch position must be maintained. Instead, a return spring 224 and return spring support 225 are used to return the selector switch stem 168 to its rest position during operation.

The return spring 224 is shown in FIG. 34 and is preferably a wound stainless steel torsion spring having outwardly turned feet 226 at its end portions.

The return spring support 225 (FIGS. 35 and 36) is preferably stamped and formed from strip steel and has a pair of annular leg portions 227 spaced axially apart and connected by a generally planar bight portion 229. Each leg portion 227 preferably has an inwardly turned tang 230 along one side portion thereof opposite the tang 230 on the other leg portion 227. Aligned slots 231 are preferably provided through both leg portions 227 centrally of the bight portion 229.

The return spring 224 is inserted between the leg portions 227 of the return spring support 225 with each foot 226 of the return spring 224 engaging one of the tangs 230 on the return spring support 225 as shown in FIG. 32. Preferably, the return spring 224 is under tension in this position to assure that the feet 226 will be properly positioned and held against the tangs 230.

A momentary selector switch stop ring 171m is provided with an upstanding tab 232 (see FIG. 32). The stop ring 171m (for the purposes of this example, a three position stop ring) is placed in the body 16 and around the selector switch stem 168 with the tab 232 rearwardly directed. The stop ring 171m is aligned in the same manner as previously described in relation to the stop ring 171 for the maintained selector switch.

The selector switch stem 168 is oriented so that the tongue portion 196 is in the rest position and the return spring 224 and return spring support 225 are placed over the selector switch stem 168 with the tongue portion 196 through the aligned slots 231. Now the tab 232 on the stop ring 171m abuts one foot 226 of the return spring 224 on the same side as the corresponding tang 230 on the return spring support 225 abuts the same foot 226.

A momentary selector switch retainer 27m has an upstanding tab 234 on a forward face thereof (FIG. 33). When the retainer is placed on the body 16, the tab 234 abuts the other foot 226 of the return spring 224 on the same side as the corresponding tang 230 on the return spring support 225 abuts the same foot 226.

Thus a three position momentary selector switch assembly 164m is formed. When the knob 165 and, correspondingly, the selector switch stem 168 are rotated in either direction, the return spring support 225 also rotates, due to the engagement of the tongue portion 196 in the aligned slots 231. This causes a corresponding motion of the return spring 224.

However, when the selector switch stem 168 is rotated in the direction indicated by the arrow 235 in FIG. 32, the retainer tab 234 engages its corresponding return spring foot 226 and holds it against rotation. Thus, as the selector switch stem 168 rotates, the tension of the return spring 224 is increased, since the tang 230 adjacent the stop ring retainer tab 232 pulls its corresponding foot 226 and causes it to rotate with the return spring support 225 and selector switch stem 168. When the selector switch stem 168 is released, the return spring 224 applies sufficient force to pull the return spring support 225, and with it the selector switch stem 168, back to the rest position.

Similarly, when the selector switch stem 168 is rotated in the direction opposite that indicated by the arrow 235, the stop ring tab 232 engages its corresponding return spring foot 226 and holds it against rotation so that the tension of the return spring is increased to pull the selector switch stem 168 back to its rest position upon release of the selector switch knob 165. In this manner a three position selector switch having a central rest position and a momentary position on either side may be formed.

It should be apparent from the foregoing discussion that a two position selector switch may be formed with a rest position and a single momentary position only to one side thereof by using a two position momentary stop ring 171m. Because return action is only desired in one direction, either the stop ring tab 232 or the retainer tab 234 may be omitted, depending on the side of the rest position to be used.

To provide a three position selector switch which has a maintained position on one side and a momentary position on the other side of a central position, as is illustrated in FIG. 37, both detent means and spring return means must be included. The detent means must function only in the maintained position and the spring return means must function only in the momentary position. Thus, in this embodiment, the index pins 169 and index pin spring 170 are used as detent means for the maintained position and the return spring 224 and return spring support 225 are used as spring return means for the momentary position.

So that the return spring 224 will only function during operation to one side, either the stop ring tab 232 or the retainer tab 234 is omitted. The tab which is used determines the direction of the momentary position.

The index pins 169 are positioned within the body 16 so that when the selector switch stem 168 is in its rest position, the index pins 169 are at one edge of the planar surfaces 194. When the selector switch stem 168 is rotated into the momentary position, the index pins 169 slide across the corresponding planar surfaces 194 so that the detent means is inoperative and does not interfere with the action of the return spring 224. When the selector switch stem 168 is rotated into the maintained position, the index pins 169 and index pin spring 170 interact with the cam surface 189 so that the detent means operates as hereinbefore described. It should be readily apparent that a momentary

3,740,501 maintained selector switch with more than one maintained position may be formed by using s stop ring 171 providing four or more positions.

An illuminated selector switch assembly 1641 is illustrated in FIG. 38 and may be of the maintained, momentary or momentary-maintained variety. As in the illuminated push button switch assembly 111, the lamp 130 is held by a pair of lamp terminals 131 which are locked within the selector switch stem 168 by the lamp terminal holder 132. The rear end portions 142 of the lamp terminals 131 are in electrical contact with the output terminals 162 of the light module 156.

To accommodate the lamp assembly, the selector switch stem 168 is provided with a substantially cylindrically longitudinal opening 235 (see FIG. 22). A rear portion 236 of the longitudinal opening 235 has a narrow section 237 defining a rearwardly directed shoulder 239 to accommodate assembly of the lamp assembly in a manner similar to that described for the illuminated push-button assembly 111. (see FIGS. 18 and 19)

Since the selector switch stem 168 rotates during operation while the output terminals 162 of the light module 156 remain stationary, the formation of the longitudinal opening 235 must enable the lamp terminals 131 to rotate relative to the selector switch stem 168 so that the lamp terminals 131 will be in a fixed position for constant electrical· contact with the output terminals 162. Therefore, the alignment bosses 155 which were used in the push button stem 25 (see FIG. 5) have not been added to the selector switch stem 168.

When the illuminated selector switch assembly 1641 is put together, the lamp assembly is positioned so that when the light module 156 is attached to the body 16, the rear end portions 142 of the lamp terminals 131 are in electrical contact with the output terminals 162 of the light module 156. When the selector switch is operated, causing the selector switch 168 to be rotated within the body 16, the light module 156 holds the lamp assembly against rotation so that the selector switch may be illuminated in any or all of its positions.

Thus, a switch assembly has been illustrated which has both push-button and selector switch modes of operation, may be illuminated or non-illuminated and can provide a large variety of switching programs. The selector switch mode of operation provides momentary, maintained and momentary-maintained operation and from two to eight position switching. The large variety of switching programs is provided through the use of a minimal number of different parts. Since the switch assembly can be made very small and all wiring connections and contact condition indicators are directed to45 ward the rear, a plurality of assemblies may be contained in a smaller space than is the case with many prior art devices. However, it should be noted that the switch assembly of the present invention is adaptable for use as a larger scale unit.