Door latching system

[57] ABSTRACT

A substantially fool-proof system for latching a door in a closed position in response to the actuation of a manually actuable electric circuit controlling device to a first position and unlatching the door in response to the actuation of the device to a second position. The system is especially adaptable to the latching and unlatching of an oven door of a self-cleaning oven during a self-cleaning cycle of operation of the oven and, when such system is so employed, the system is inoperable to a door latching condition unless the oven door is closed. Following a self-cleaning cycle of operation of the oven, the system maintains the oven door in the door latched condition until the temperature in the oven falls below a selected safe oven temperature. An electrically energizable coil and an associated plunger actuated by the energization of the coil are used to control the latching and unlatching of a door in the latching system. Such coil and plunger are preferably a solenoid coil and its associated movable core.

Claims, 11 Drawing Figures

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PATENTED SEP 41973

3,757» 084

SHEET 1 OF 8

<img file="US3757084A_D0002.tif" />

<img file="US3757084A_D0003.tif" />

INVENTORS.

Byron R. McLean Donald R. Shriner John C. Swan

AGENT

PATENTED SEP 41973

3.75L084

SHEET 2 Of 8

<img file="US3757084A_D0004.tif" />

<img file="US3757084A_D0005.tif" />

<img file="US3757084A_D0006.tif" />

INVENTORS.

Byron R. McLean Donald R. Shriner

John C. Swan

SY

AGENT

PATENTED SEP 41973

3,757,084

SHEET 3 OF 8

<img file="US3757084A_D0007.tif" />

John C. Swan

<img file="US3757084A_D0008.tif" />

PATENTED SEP 41973

3.757,084

SHEET U OF 8

<img file="US3757084A_D0009.tif" />

<img file="US3757084A_D0010.tif" />

Byron R. McLean Donald R. Shriner John C. Swan

BY

<img file="US3757084A_D0011.tif" />

PATENTEOSEP 41973

3,757,084

SHEET 5 OF 8

<img file="US3757084A_D0012.tif" />

<img file="US3757084A_D0013.tif" />

INVENTORS.

Byron R. McLean Donald R. Shriner John C. Swan

AGENT

PATENTED SEP 41973

3,757.084

SHEET 6 OF 8

<img file="US3757084A_D0014.tif" />

Byron R. McLean Donald R. Shriner

John C. Swan

BY

AGENT

PAIENTEQSEP 41973

3,757,084

SHEET 7 OF 8

<img file="US3757084A_D0015.tif" />

<img file="US3757084A_D0016.tif" />

131α

<img file="US3757084A_D0017.tif" />

INVENTORS.

Byron R. McLean Donald R. Shriner John C. Swan

BY

AGENT

PATENTED SEP 41973

3,757.084

SHEET 8 OF 8

<img file="US3757084A_D0018.tif" />

<img file="US3757084A_D0019.tif" />

John C. Swan

<img file="US3757084A_D0020.tif" />

AGENT

3,757,084

DOOR LATCHING SYSTEM

This is a continuation-in-part of our copending application, Ser. No. 87,828, filed Nov. 9, 1970 and now abandoned, entitled Door Latching System.

BACKGROUND OF THE INVENTION

There is disclosed in U.S. Pat. No. 3,474,226, issued Oct. 21, 1969 to Herbert A. Kauranen, a system for latching an oven door in a closed position during a selfcleaning cycle of operation of the oven and unlatching said door following such operation cycle. The latching system of such patent employes an electric motor and an associated gear box for moving the oven door latching device per se to and from door latching positions, and the system is, therefore, somewhat slow in latching said door when a cycle of a self-cleaning operation of the oven equipped with such a system is initiated. It is, accordingly, the object of the present invention to provide a door latching system which, upon the manual actuation of an electric circuit controlling device to a position for initiating the latching of a door, actuates the door latching device per se to a door latching position substantially instantaneously, that is, with very little or no perceptable delay between the actuation of said circuit controlling device to its said door latching initiating position and the actual latching of the door.

SUMMARY OF THE INVENTION

In accomplishing the above object of the invention there is provided an electromagnetic winding or coil, and an associated plunger which is actuated, when said winding or coil is electrically energized, to in turn actuate a door latching device per se. Said coil and plunger preferably comprise a solenoid coil and its movable core or plunger which is coupled to said latching device for actuations thereof between door latching and unlatching positions.

Other objects and characteristic features of the invention will become apparent as the description proceeds.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a top plan view of a door latching mechanism in accordance with a first embodiment of the invention, such view showing the mechanism when in a normal or door unlatched position;

FIG. 2 comprises a view similar to FIG. 1 but showing the first embodiment of the door latching mechanism when actuated to a position about halfway between door unlatched and door latching positions;

FIG. 3 is a view similar to FIGS. 1 and 2 but showing the door latching mechanism of the first embodiment of the invention when in a fully actuated or door latching position;

FIG. 4 comprises an elevational view of the mechanism of FIGS. 1, 2 and 3, such view being taken generally along line 4—4 of FIG. 3;

FIG. 5 comprises a schematic wiring diagram of the first embodiment of the door latching system of the invention when used in latching and unlatching the door of a self-cleaning oven, such view showing the components of the system when the door latching mechanism of the first embodiment of the invention is in the doorunlatched position; invention

FIG. 6 is a top plan view similar to FIG. 1 but illustrating a second embodiment of the invention;

FIG. 7 comprises a view similar to FIG. 6 but showing the second embodiment of the door latching mechanism of the second embodiment of the invention when actuated to a position about halfway between door unlatched and door latching positions;

FIG. 8 is a view similar to FIGS. 6 and 7 but showing the door latching mechanism of the second embodiment of the invention when in a fully actuated or door latching position;

FIG. 9 comprises an elevational view of the mechanism of FIGS. 6,7 and 8, such view being taken generally along line 9—9 of FIG. 8;

FIG. 10 comprises a detail view of a part of the mechanism of FIGS. 6 through 9, such view being taken along line 10—10 of FIG. 9; and

FIG. 11 comprises a schematic wiring diagram of the door latching system of the second embodiment of the invention when used in latching and unlatching the door of a self-cleaning oven, such view showing the components of the system when the door latching mechanism of the second embodiment of the invention is in the door-unlatched position.

Similar reference characters refer to similar parts in each of the FIGS, of the drawings.

PREFERRED EMBODIMENTS OF THE INVENTION

Referring first to FIGS. 1 through 4 of the drawings in detail, there is shown a door latching mechanism 10 comprising a component support plate 11 having secured to the upper surface thereof, as by screws such as 12α (FIG. 4) an electromagnetic coil or winding 12 having an associated core or plunger 13. Coil 12 may, for example, be a solenoid coil whose core or plunger 13 is retracted into the coil whenever it is energized by electrical energy or current. Coil or winding 12 has a pair of terminals T4 and TS across which a source of electrical energy is, at times, connected for energization of the coil as hereinafter discussed in detail. A groove is provided about the outer periphery of core or plunger 13, near the right hand end of such core or plunger when viewing FIGS. 1 through 4, and a spring member 14 is disposed in said groove to limit the distance to which core or plunger 13 is retracted into winding or coil 12.

A cam member or eccentric 18 is pivotally or rotatably mounted on the upper surface of support plate 11 as by a pivot pin or rivet 19 which extends downwardly through a base portion or pedestal 18b (FIG. 4) of eccentric or cam member 18 and through support plate 11. The extreme lower end of rivet 19 is penned over against the bottom surface of plate 11 and cam member or eccentric 18 is, thereby, pivotally or rotatably mounted as mentioned above. Eccentric or cam member 18 is provided with a depending and somewhat semi-circular apron portion 18α (FIG. 4) which depends from the lower surface of the eccentric or cam member adjacent a part of the outer periphery thereof. The purpose of portion 18α will be pointed out hereinafter.

A relatively short crank arm 20 has a first end 20α which surrounds the upper end of pin or rivet 19 and is rotatable thereabout. Crank arm 20 is securely fastened, in any convenient manner, to the upper surface of cam member or eccentric 18. Thus, crank arm 20 and eccentric or cam member 18 are rotatable in unison about the upper end of pivot pin or rivet 19. It will

3.757.084 be apparent, therefore, that crank arm 20, when rotated as hereinafter discussed, will cause corresponding rotation of cam member or eccentric 18. Another upright pivot pin or rivet 29 as a lower end which extends downwardly through the second end 20b of crank arm 20 and through eccentric or cam member 18 to which it is securely fastened. End 20b of crank arm 20 is rotatable about the outer periphery of pin or rivet 29.

First ends of first and second linking or coupling members 17 and 3®, respectively, also surround pin or rivet 29 and are rotatable thereabout. A groove is provided in the outer periphery of pin or rivet 29 near the upper end thereof and a first end of an expansible spring 28 extends into said groove and is looped or hooked thereabout to secure such end of the spring to pin or rivet 29 in a rotatable relationship therewith. The second end of spring 28 is looped or hooked about an upper portion 27α (FIG. 4) of a screw 27 to be hereinafter further discussed.

The lower end of an upright bumper supporting member 16α is secured to the upper surface of support plate 11 in any convenient manner, such as by welding for example, and there is mounted on the upper end of such support member a bumper or button 16 which is preferably made of a resilient material such as rubber, for example. The left hand or second end of linking or coupling member 17 is bent to provide a downwardly extending portion 17α which contacts button or bumper 16 to limit the distance of right hand movement of plunger or core 13, that is, the distance of movement of plunger or core 13 out of coil or winding 12. The right hand end (viewing FIG. 4) of plunger or core 13 is provided with a horizontal slot into which linking or coupling member 17 extends, and a pin 15 extends downwardly through the right hand end of plunger or core 13 and through member 17 to pivotally link such member to such end of plunger or core 13.

An electrical circuit controlling device or switch 25 is fastened to the upper surface of plate 11 as by a screw 26 and the previously mentioned screw 27 both of which extend downwardly through plate 11. Circuit controlling device or switch 25 includes an electrical contact actuating means comprising a spring return plunger 25b and a leaf spring plunger-actuating member 25α. Member 25α bears against the outer surface of depending portion 18α of eccentric or cam member 18 and is actuated thereby during rotations of the eccentric or cam member as hereinafter further discussed in detail in conjunction with FIG. 5 of the drawings. Leaf spring member 25α in turn bears against the end of spring return plunger 25b of switch 25 and such plunger is at times depressed by member 25α to actuate electric circuit controlling contacts provided internally in switch 25 and which will also be further discussed hereinafter. Switch 25 also includes terminals ΤΙ, T2, T3 and T6 to which electric conductors are connected as hereinafter discussed.

Returning to previously mentioned linking or coupling member 30, the second end of such member is pivotally coupled, as by a rivet or pin 32, to a latching member or device 31 which is, in turn, pivotally coupled, as by a rivet or pin 34, to a support plate or bracket 35 which is mounted in any convenient manner adjacent a slot 41 embodied in a door 40 which is at times latched by the apparatus of the invention. Latching member or device 31 includes an extending finger 31α which extends through slot 41 in door 40 and which, when device or member 31 is operated to a door latching position as hereinafter discussed, contacts the outer periphery of a keeper 33 provided in or on door 4® and latches such door in a closed position. The simi5 larity between the latching arrangement of the present invention and that of the previously cited patent to Herbert A. Kauranen will be readily apparent from a brief glance at FIG. 2 of such patent.

Referring now to FIG. 5 of the drawings, there is 10 shown schematically the door latching mechanism 10 including support plate 11, coil or winding 12 and its associated plunger or core 13, coupling member 17, eccentric or cam member 18, and electric circuit controlling device or switch 25 and its associated leaf spring ¹⁵ or resilient plunger-actuating member 25α and spring return plunger 25b of the switch.

Circuit controlling device or switch 25 is provided with first and second sets of contacts 45-47 and 45-46, respectively, with movable contact member 45 being ²⁰ common to both such sets of contacts. The first set of contacts 45-47 are closed only when cam member or eccentric 18 is in its first position shown in FIG. 1 or is rotating between such first position and a position about halfway towards a second position of the eccentric or cam member shown in FIG. 3. The second set of contacts 45-46 are closed only when cam member or eccentric 18 is in its said second position shown in FIG. 3 or is rotating between such second position and ₃0 a position about halfway towards said first position of the eccentric or cam member shown in FIG. 1. It will be apparent, therefore, that both of the first and second sets of contacts 45-47 and 45-46, respectively, are momentarily in opened conditions while cam member 18 35 is rotating through a position near its halfway or midway position shown in FIG. 2. Also, the set of contacts 45-46 are in an opened condition when the set of contacts 45-47 are closed, and the set of contacts 45-47 are in an opened condition when the set of contacts 40 45-46 are closed. This is believed readily apparent from FIG. 5 of the drawings since movable contact member 45 is, as previously mentioned, common to both said sets of contacts.

Circuit controlling device or switch 25 is illustrated 45 in FIG. 5 as having a third set of contacts 48-49, such contacts being closed only when cam member or eccentric 18 is in its position shown in FIG. 3 or is in any rotational position substantially halfway between its position shown in FIG. 3 and its position shown in FIG. ⁵⁰ 2, that is, only when the door latching mechanism is relatively close to or is in its door latching position. Such third set of contacts are employed when the door latching system of the invention is used for latching the door of an oven such as 43 (FIG. 5) during a self-cleaning ⁵⁵ cycle of operation of such oven. Circuit controlling devices or switches such as 25 are well known as will be readily recognized by those skilled in the art.

There is further shown in FIG. 5 a three position electric circuit controlling device or cycle selector 65 ineluding a manually actuable or rotatable dial 66 having a pointer 66α shown as pointing to an “off” position of device 65 and its control dial 66. Dial 66 is rotatable to further point to “bake” or “clean” positions and, dur₆₅ ing such rotation, circuit controlling device or cycle se³ lector 65 is correspondingly actuated to close or open electric circuit controlling sets of contacts as discussed below.

3,757,084

6 of the drawings. Such terminals will be discussed further hereinafter.

It is expedient to point out at this time that a three wire 240 volt A.C. power supply or source is provided 5 for the energization of the electrical components used in the system disclosed. However, such power supply or source per se is not shown in the drawings for purposes of simplification thereof but said source includes power lines designated LI and L2, and a neutral line N as is ¹⁰ well known in the art.

Returning to FIG. 5 of the drawings, taken in conjunction with FIGS. 1 through 4, there is shown a first series electrical circuit for the e energization of coil 12, such circuit extending from power line LI to terminal ¹⁵ T3 of circuit controlling device 25 and through such terminal to movable member 45 of the set of contacts 45-46 of circuit controlling device 25 when such contacts are in their closed condition, terminal T1 of de₂₀ vice or switch 25, conductor Cl, the set of contacts 50-51 of cycle selector 65 in their closed condition, conductor C3, contacts 61-62 actuated to their closed condition by bimetallic member 60α, conductor C4, contacts 63-64 of door switch 67 in their closed condi25 tion, conductor C5, terminal T5 of coil 12, and thence through such coil to terminal T4 and the aforesaid neutral power line N.

A second series electrical circuit for the energization ofcoil 12 may be traced from power line LI to terminal 30 T3 of circuit controlling device 25, the set of contacts 45-47 of device 25 in their closed condition, terminal T2 of device 25, conductor C2, the set of contacts 50-52 of cycle selector or device 65 in their closed condition to conductor C3 and thence over the remain³⁵ der of the first series electrical circuit traced above to neutral power line N.

The “bake” coil or winding 58 of the oven 43 has a first energizing circuit which extends from power line ₄θ LI and through the “bake” cycle control circuits (not shown) to conductor C9, the set of contacts 53-54 of device or cycle selector 65 in their closed condition, thence to conductor C7 and through the “bake” coil 58 to power line L2. The “bake” cycle control circuits and 45 the connection from power line LI to such circuits are not shown in FIG. 5 for purposes of simplicity of the drawings and since they do not, per se, form part of the present invention.

Coil or winding 58 has a second energizing circuit 50 which may be traced from power line LI, terminal T3, the set of contacts 48-49 of switch or circuit controlling device 25 in their closed condition, terminal T6, conductor C6, the set of contacts 53-55 of cycle selector 65 in their closed condition, conductor C7 and 55 thence through coil or winding 58 to power line L2.

The “clean” coil or winding 59 of oven 43 has an energizing circuit which may be traced from power line LI, terminal T3, the set of contacts 48-49 of circuit controlling device 25 in their closed condition, termi⁶⁰ nal T6, conductor C6, the set of contacts 56-57 of cycle selector or circuit controlling device 65 in their closed condition, conductor C8, and thence through coil or winding 59 to power line L2.

The apparatus of the first embodiment of the inven³ tion having been described in detail, several operational examples of the system comprising such embodiment will now be given.

Circuit controlling device 65 has a first set of contacts 50-51 which are closed only when dial 66 and, therefore, device 65 are in the “off” position as shown in FIG. 5, and a second set of contacts 50-52 which are closed only when dial 66 and, therefore, device 65 are in the “clean” position indicated in FIG. 5. Movable contact member 50 is common to both said sets of contacts.

Circuit controlling device 65 also has third and fourth sets of contacts 53-54 and 53-55, respectively, with movable contact member 53 being common to both such sets of contacts. The first set of contacts 53-54 are closed only when dial 66 and, therefore, device or switch 65 are set for a “bake” cycle of operation of oven 43, and the second set of contacts 53-55 are closed only when dial 66 and, therefore, device 65 are set for a “clean” cycle of operation of oven 43. Movable contact member 53 of said sets of contacts is, therefore, shown in FIG. 5 as being out of contact with both fixed contact points 54 and 55 since dial 66 and, therefore, device 65 are shown in FIG. 5 as set to “off”. Circuit controlling device or switch 65 further includes a fifth set of contacts 56-57 which are closed only when dial 66 and device 65 are set for a “clean” cycle of operation of oven 43. Contacts 56—57 are, therefore, shown in their opened condition in FIG. 5.

FIG. 5 also shows a pair or set of thermostatically actuable electric circuit controlling contacts 61-62 of a thermostatic switch 60, such contacts being in circuit closing conditions when a bimetallic member 60α senses that the temperature in oven 43, which is provided with the door latching system of the present invention, is below a selected safe temperature. When the temperature in said oven 43 raises above said selected safe temperature which may, for example, be about 55O°F., bimetallic member 60α is actuated by such temperature to, in tum, actuate circuit controlling contacts 61-62 to circuit opening conditions. Such contacts do not thereafter return to their circuit closing conditions until the temperature in said oven falls to or below said selected safe temperature. Thermostatically actuated devices or switches such as 60 and including contacts such as 61-62, and a bimetallic member such as 60α are well known in the art.

A further electric circuit controlling device 67 is also shown in FIG. 5 and includes a set of contacts 63-64 which are actuated to a circuit closing condition only when the door of the aforesaid oven is closed. Such contacts are, therefore, shown in FIG. 5 in their circuit closing condition since the oven door is assumed to be closed. Door actuated switches such as 67 are also well known in the art.

A first electrical resistance heating coil or winding 58 is shown as provided in oven 43 which is assumed to be equipped with the door latching system of the present invention. Such coil or winding 58 is designated in FIG. 5 of the drawings as a “bake” coil and, as hereinafter discussed in more detail, such coil is energized during both “bake” and “clean” cycles of operation of oven 43. A second electrical resistance heating coil or winding 59 designated as a “clean” coil is also shown in FIG. 5 and, as also hereinafter discussed in greater detail, coil 59 is energized only during “clean” cycles of operation of oven 43.

A group of terminals T1 through T6 are shown in FIG. 5 and such terminals correspond to terminals T1 through T6, respectively, shown in FIGS. 1 through 4

3,757,084

Operational Examples of the First Embodiment of the Invention

It will first be assumed that the apparatus is in its positions and/or conditions illustrated in FIGS. 1 and 5 of the drawings, that is, that the pointer 66α (FIG. 5) of dial 66 is pointing to the “off” position, the door 40 of oven 43 is closed and, therefore, contacts 63-64 are in their closed conditions, and that contacts 61-62 are closed by bimetallic member 60α. Under such conditions, none of the previously described or traced electrical circuits are closed. If a housewife or other user of the oven now turns dial 66 to the “bake” cycle of the oven, only coil 58 is energized over its “bake” cycle control circuits and thence over conductor C9 and the set of contacts 53-54 of cycle selector 65 in their closed condition.

If it is desired to initiate a self-cleaning cycle of operation of the oven, dial 66 is rotated so that its pointer 66α points to the “clean” position of the dial. Such rotation actuates the sets of contacts S®-52, 53-55 and 56-57 of circuit controlling device 65 to their closed conditions. Assuming that the oven door is closed and that the oven temperature is below the temperature at which contacts 61-62 are actuated to their opened condition, the closing of the set of contacts 50-52 completes the previously described second series electrical circuit for the energizing of coil 12. The energization of coil 12 causes retraction of core or plunger 13 into the coil and thereby actuates the parts of the door latching system to their positions shown in FIG. 2. The rotation of eccentric 18 towards its rotational position shown in FIG. 2 causes depending portion 18α to actuate member 25α of switch 25 to, in turn, partially depress plunger or button 25b of switch 25 and, thereby, open the set of contacts 45-47 of switch 25 (FIG. 5) about the time when eccentric or cam member 18 reaches its rotational position shown in FIG. 2, that is to say, contacts 45-47 of switch 25 are opened when eccentric 18 arrives at a position about halfway in its rotational movement towards its position shown in FIG. 3. When said opening of said set of contacts 45-47 deenergizes coil 12 (see FIG. 5) about the time when cam member or eccentric 18 reaches its rotational position shown in FIG. 2 as mentioned above, the kinetic energy of eccentric or cam member 18 rotates such cam member or eccentric past its halfway rotational position shown in FIG. 2, that is, past its rotational position halfway between the rotational positions of the cam member or eccentric shown in FIG. 1, and FIGS. 3 and 4, and spring 28 then completes the rotation of cam member or eccentric 18 to its position shown in FIGS. 3 and 4. During the rotation of eccentric or cam member 18 from its position shown in FIG. 1 to its position shown in FIGS. 3 and 4, door latching device or member 31 is actuated or rotated from its position shown in FIG. 1 to its position shown in FIG. 3 so that the finger portion 31α of member 31 contacts and partially surrounds keeper 33 on door 40 to securely latch such door in its closed position.

In the foregoing described rotation of eccentric or cam member 18, when such member is at a position slightly past its rotational position shown in FIG. 2, actuating member 25α is further actuated by depending portion 18α of eccentric or cam member 18 to further depress plunger 25b of switch 25. The set of contacts 45-46 of switch 25 (FIG. 5) are thereby actuated to their closed condition to prepare the previously described or traced first series electrical circuit for the energization of coil 12. Also during the rotation of cam member or eccentric 18 from its position shown in FIG. 2 to its position shown in FIG. 3, the set of contacts 48-49 are actuated to their closed condition by still further depression of plunger 25b of switch 25, and both the “bake” and “clean” windings or coils 58 and 59 (FIG. 5) are thereby energized to raise the temperature of oven 43 to a pyrolytic temperature for the selfcleaning cycle of operation of the oven. During such raise in temperature, the set of contacts 61-62 of switch 60 are actuated by bimetallic member 60α to their opened condition when the temperature in the oven exceeds the previously mentioned safe temperature for persons using the oven.

At the completion of the self-cleaning cycle of operation discussed above, dial 66 is rotated so that its pointer 66α points to the “off” position of circuit controlling device or cycle selector 65 and the sets of contacts 50-51 are, thereby, reactuated to their closed condition shown in FIG. 5. At the same time movable contact members 53 and 56 are moved to their open positions shown in FIG. 5 and the energizing circuits for heating coils or windings 58 and 59 are thereby opened to deenergize such coils or windings and permit oven 43 to cool.

When the set of contacts 50-51 are actuated to their closed conditions as mentioned above, the previously described or traced first series electrical circuit for energizing coil 12 is prepared and, when oven 43 cools sufficiently that the set of contacts 61-62 are actuated to their closed condition by bimetallic member 60α, said first series circuit is completed, coil 12 is again energized and plunger or core 13 is, thereby, retracted into coil 12 to rotate eccentric 18 from its rotational position shown in FIGS. 3 and 4 towards its rotational position shown in FIG. 2. When eccentric or cam member 18 has, during said rotation thereof, rotated sufficiently towards its position shown in FIG. 2, plunger 25b of switch 25 is permitted by actuating member 25α of the switch to be partly returned by its spring return means towards its non-depressed position and, at such time, the set of contacts 48-49 are again actuated to their opened condition shown in FIG. 5.

About the time cam member or eccentric 18 reaches its rotational position shown in FIG. 2, actuating member 25α of switch 25 moves to permit plunger 25b of such switch to be further returned by its spring return means towards its non-depressed position and, at such time, the set of contacts 45-46 of switch 25 are actuated to their opened condition. This opens the first series circuit for energizing coil 12. The kinetic energy of eccentric 18 again rotates such member past its halfway position shown in FIG. 2, that is, past its rotational position halfway between the rotational positions of the eccentric or cam member 18 shown in FIGS. 3 and 4, and FIG. 1, and spring 28 then completes the rotation of said member 18 to its position shown in FIG. 1, door latching device or member 31 is thus actuated or rotated from its position shown in FIG. 3 to its position shown in FIG. 1 so that door 40 of the oven such as 43 (FIG. 5) is unlatched.

In the foregoing described rotation of cam member or eccentric 18 from its position shown in FIGS. 3 and 4 to its position shown in FIG. 1, when such member is at a position slightly past its rotational position shown

3,757,084 in FIG. 2, actuating member 25α of switch 25 permits plunger 25b of such switch to be actuated to its fully non-depressed position. The set of contacts 45—47 of switch 25 (FIG. 5) are thereby actuated to their closed condition to again prepare the previously described or traced second series electrical circuit for the energization of coil 12. The apparatus and its parts are now again in its positions or conditions shown in FIGS. 1 and 5 of the drawings.

If, shortly after the initiation of a self-cleaning cycle of operation as previously described, it is decided for some reason to interrupt such cycle and, for such reason, cycle selector or circuit controlling device 65 is returned to its “off” position, the previously described first series electrical circuit for energizing coil 12 will be completed over the set of contacts 50-51 of device 65 only if the temperature in the oven is still below, or when such temperature drops below, the aforesaid safe temperature which causes bimetallic member 60α (FIG. 5) to actuate contacts 61-62 to their opened condition.

Referring now to FIGS. 6 through 9 of the drawings in detail, there is shown a door latching mechanism 110 comprising a component support plate 111 having secured to the upper surface thereof, as by screws such 25 as 112α (FIG. 9) an electromagnetic coil or winding 112 having an associated core or plunger 113. Coil 112 may, for example, be a solenoid coil whose core or plunger 113 is retracted into the coil whenever it is energized by electrical energy or current. Coil or winding 112 has a pair of terminals T104 and T105 across which a source of electrical energy is, at times, connected for energization of the coil as hereinafter discussed in detail. A groove is provided about the outer periphery of core or plunger 113, near the right hand end of such core or plunger when viewing FIGS. 6 through 9, and a spring member 114 is disposed in said groove to limit the distance to which core or plunger 113 is retracted into winding or coil 112.

A cam member 118 is pivotally or rotatably mounted on the upper surface of support plate 111 as by a pivot pin or rivet 119 which extends downwardly through a base portion or pedestal 118b (FIG. 9) of cam member 118 and through support plate 111. The extreme lower end of rivet 119 is peened over against the bottom surface of plate 111 and cam member 118 is, thereby, pivotally or rotatably mounted as mentioned above. Cam member 118 is provided with a depending and somewhat semi-circular apron portion 118α (FIG. 9) which depends from the lower surface of the cam member as illustrated in FIG. 10. The purpose of portion 118α will be pointed out hereinafter.

A relatively short crank arm 120 as a first end 120α which surrounds the upper end of pin or rivet 119 and is rotatable thereabout. Crank arm 120 is securely fastened, in any convenient manner, to the upper surface of cam member 118. Thus, crank arm 120 and cam member 118 are rotatable in unison about the upper end of pivot pin or rivet 119. It will be apparent, therefore, that crank arm 120, when rotated as hereinafter discussed, will cause corresponding rotation of cam member 118. Another upright pivot pin or rivet 129 has a lower end which extends downwardly through the second end 120b of crank arm 120 and through cam member 118 to which it is securely fastened. End 120b ofcrank arm 120 is rotatable about the outer periphery of pin or rivet 129.

First ends of first and second linking or coupling members 117 and 130, respectively, also surround pin or rivet 129 in a relatively snug relationship therewith but readily rotate thereabout. A groove is provided in 5 the outer periphery of pin or rivet 129 near the upper end thereof and a first end of an expansible spring 128 extends into said groove and is looped or hooked thereabout to secure such end of the spring to pin or rivet 129 in a rotatable relationship therewith. The second 10 end of spring 128 is looped or hooked about an upper portion 127α (FIG. 9) of a screw 127 to be hereinafter further discussed.

The lower end of an upright bumper supporting member 116α is secured to the upper surface of sup15 port plate 111 in any convenient manner, such as by welding for example, and there is mounted on the upper end of such support member a bumper or button 116 which is preferably made of a resilient material such as rubber, for example. The left hand or second 20 end of linking or coupling member 117 is bent to provide a downwardly extending portion 117α which contacts button or bumper 116 to limit the distance of right hand movement of plunger or core 113, that is, the distance of movement of plunger or core 113 out of coil or winding 112. The right hand end (viewing FIG. 9) of plunger or core 113 is provided with a horizontal slot into which linking or coupling member 117 extends, and a pin 115 extends downwardly through the right hand end of plunger or core 113 and through a suitable ³⁰ hole or slot such as 117α provided in member 117 to pivotally link such member to such end of plunger or core 113 with a selected amount of longitudinal movement of member 117 relative to pin 115 being permitted as illustrated in FIGS. 6, 7 and 8 and as hereinafter ³⁵ further discussed.

An electrical circuit controlling device or switch 125 is fastened to the upper surface of plate 111 as by a screw 126 and the previously mentioned screw 127 both of which extend donwwardly through plate 111. ⁴θ Circuit controlling device or switch 125 includes an electrical contact actuating means comprising a spring return plunger 125h and a leaf spring plunger-actuating member 125α. Member 125α is at times contacted by the outer surface of depending portion 118α of cam ⁴⁵ member 118 and is actuated thereby during rotations of the cam member as hereinafter further discussed in detail in conjunction with FIGS. 10 and 11 of the drawings. Leaf spring member 125α in turn bears against the end of spring return plunger 125b of switch 125 ⁵⁰ and such plunger is at times depressed by member 125α to actuate electric circuit controlling contacts provided internally in switch 125 and which will also be further discussed hereinafter. Switch 125 also includes terminals T101, T102, T103 and T106 to which electric conductors are connected as hereinafter discussed.

Returning to previously mentioned linking or coupling member 130, the second end of such member is pivotally coupled, as by a rivet or pin 132, to a latching member or device 131 which is in turn pivotally coupled, as by a rivet or pin 134, to a support plate or bracket 135 which is mounted in any convenient manner adjacent a slot 141 embodied in a door 140 which is at times latched by the apparatus of the invention. 65 Latching member or device 131 includes an extending finger 131α which extends through slot 141 in door 140 and which, when device or member 131 is operated to a door latching position as hereinafter discussed, con3,757,084 tacts the outer periphery of a keeper 133 provided in or on door 140 and latches such door in a closed position. The similarity between the latching arrangement of the second embodiment of the present invention and that of the previously cited patent to Herbert A. Kauranen will also be readily apparent from a brief glance at FIG. 2 of such patent.

Referring now to FIG. 11 of the drawings, there is shown schematically the door latching mechanism 110 including support plate 111, coil or winding 112 and its associated plunger or core 113, coupling member 117, cam member 118 and electric circuit controlling device or switch 125 and its associated leaf spring or resilient plunger-actuating member 125α and spring return plunger 125b of the switch.

Circuit controlling device or switch 125 is provided with first and second sets of contacts 145-147 and 145-146, respectively, with movable contact member 145 being common to both such sets of contacts. The first set of contacts 145-147 are closed only when cam member 118 is in its first position shown in FIG. 6 or is rotating between such first position and a position about halfway towards a second position of the cam member shown in FIG. S. The second set of contacts 145-146 are closed only when cam member 118 is in its said second position shown in FIG. 8 or is rotating between such second position and a position about halfway towards said first position of the cam member shown in FIG. 6. It will be apparent, therefore, that both of the first and second sets of contacts 145-147 and 145-146, respectively, are momentarily in opened conditions while cam member 118 is rotating through a position near its halfway or midway position shown in FIG. 7. Also, the set of contacts 145-146 are in an opened condition when the set of contacts 145-147 are closed, and the set of contacts 145-147 are in an opened condition when the set of contacts 145-146 are closed. This is believed readily apparent from FIG. 11 of the drawings since movable contact member 145 is, as previously mentioned, common to both said sets of contacts.

Circuit controlling device or switch 125 is illustrated in FIG. 11 as having a third set of contacts 148-149, such contacts being closed only when cam member 118 is in its position shown in FIG. 8 or is in any rotational position substantially halfway between its position shown in FIG. 8 and its position shown in FIG. 7, that is, only when the door latching mechanism is relatively close to or is in its door latching position. Such third set of contacts are employed when the door latching system of the invention is used for latching the door of an oven such as 143 (FIG. 11) during a self-cleaning cycle of operation of such oven.

There is further shown in FIG. 11 a three position electric circuit controlling device or cycle selector 165 including a manually actuable or rotatable dial 166 having a pointer 166α shown as pointing to an “off” position of device 165 and its control dial 166. Dial 166 is rotatable to further point to “bake” or “clean” positions and, during such rotation, circuit controlling device or cycle selector 165 is correspondingly actuated to close or open electric circuit controlling sets of contacts as discussed below.

Circuit controlling device 165 has a first set of contacts 150-151 which are closed only when dial 66 and, therefore, device 165 are in the “off position as shown in FIG. 11, and a second set of contacts 150-152 which are closed only when dial 166 and, therefore, device 165 are in the “clean” position indicated in FIG. II. Movable contact member 150 is common to both said sets of contacts.

Circuit controlling device 165 also has third and fourth sets of contacts 153-154 and 154-155, respectively, with movable contact member 153 being common to both such sets of contacts. The first set of contacts 153-154 are closed only when dial 166 and, 10 therefore, device or switch 165 are set for a “bake” cycle of operation of oven 143, and the second set of contacts 153-155 are closed only when dial 166 and, therefore, device 165 are set for a “clean” cycle of operation of oven 143. Movable contact member 153 of 15 _said sets of contacts is, therefore, shown in FIG. 11 as being out of contact with both fixed contact points 154 and 155 since dial 166 and, therefore, device 165 are shown in FIG. 11, as set to “off.” Circuit controlling device or switch 165 further includes a fifth set of con²⁰ tacts 156-157 which are closed only when dial 166 and device 165 are set for a “clean” cycle of operation of oven 143. Contacts 156-157 are, therefore, shown in theiropenedconditioninFIG.il.

FIG. 11 also shows a pair or set of thermostatically actuable electric circuit controlling contacts 161-162 of a thermostatic switch 160, such contacts being in circuit closing conditions when a bimetallic member 160α senses that the temperature in oven 143, which is pro20 vided with the door latching system of the present invention, is below a selected safe temperature. When the temperature in said oven 143 raises above said selected safe temperature which may, for example, be about 550°F., bimetallic member 160α is actuated by 35 such temperature to, in turn, actuate circuit controlling contacts 161-162 to circuit opening conditions. Such contacts do not thereafter return to their circuit closing conditions until the temperature in said oven falls to or below said selected safe temperature. Thermostatically 40 actuated devices or switches such as 160 and including contacts such as 161—162, and a bimetallic member such as 160α are well known in the art.

A further electric circuit controlling device 167 is also shown in FIG. 11 and includes a set of contacts

163-164 which are actuated to a circuit closing condition only when the door of the aforesaid oven is closed. Such contacts are, therefore, shown in FIG. 11 in their circuit closing condition since the oven door is assumed to be closed. Door actuated switches such as 167 are _ai_{so we}n known in the art.

A first electrical resistance heating coil or winding 158 is shown as provided in oven 143 which is assumed to be equipped with a door latching system of the present invention. Such coil or winding 158 is designated in FIG. 11 of the drawings as a “bake” coil and, as hereinafter discussed in more detail, such coil is energized during both “bake” and “clean” cycles of operation of oven 143. A second electrical resistance heating coil or winding 159 designated as a “clean” coil is also shown in FIG. 11 and, as also hereinafter discussed in greater detail, coil 159 is energized only during “clean” cycles of operation of oven 143.

A group of terminals T101 through T106 are also shown in FIG. 11 and such terminals correspond to terminals T101 through T106, respectively, shown in FIGS. 6 through 9 of the drawings. Such terminals will be discussed further hereinafter.

3,757,084

Returning to FIG. 11 of the drawings, taken in conjunction with FIGS. 6 through 9, there is shown a first series electrical circuit for the energization of coil 112, such circuit extending from power line LI to terminal T103 of circuit controlling device 125 and through such terminal to movable member 145 of the set of contacts 145-146 of circuit controlling device 125 when such contacts are in their closed condition, terminal T101 of device or switch 125, conductor C101, the set of contacts 150-151 of cycle selector 165 in their closed condition, conductor C103 contacts 161-162 actuated to their closed condition by bimetallic member 160α, conductor C104, contacts 163-164 of door switch 167 in their closed condition, conductor C105, terminal T105 of coil 112, and thence through such coil to terminal T104 and the aforesaid neutral power line N.

A second series electrical circuit for the energization of coil 112 may be traced from power line LI to terminal T103 of circuit controlling device 125, the set of contacts 145-147 of device 125 in their closed condition, terminal T102 of device 125, conductor C102, the set of contacts 150-152 of cycle selector or device 165 in their closed condition to conductor C103 and thence over the remainder of the first series electrical circuit traced above to neutral power line N.

The “bake” coil or winding 158 of the oven 143 has a first energizing circuit which extends from power line LI and through the “bake” cycle control circuits (not shown) to conductor C109, the set of contacts 153-154 of device or cycle selector 165 in their closed condition, thence to conductor C107 and through the “bake” coil 158 to power line L2. The “bake” cycle control circuits and the connection from power line LI to such circuits are not shown in FIG. 11 for purposes of simplicity of the drawings and since they do not, per se, form part of the present invention.

Coil or winding 158 has a second energizing circuit which may be traced from power line LI, terminal T103, the set of contacts 148-149 of switch or circuit controlling device 125 in their closed condition, terminal T106, conductor C106, the set of contacts 153-155 of cycle selector 165 in their closed condition, conductor C107 and thence through coil or winding 158 to power line L2.

The “clean” coil or winding 159 of oven 143 has an energizing circuit which may be traced from power line LI, terminal T103, the set of contacts 148-149 of circuit controlling device 125 in their closed condition, terminal T106, conductor Cl06, the set of contacts 156-157 of cycle selector or circuit controlling device 165 in their closed condition, conductor C108, and thence through coil or winding 159 to power line L2.

The apparatus of the second embodiment of the invention having been described in detail, several operational examples of the system comprising such embodiment will now be given.

Operational Examples of the Second Embodiment of the Invention

It will first be assumed that the apparatus is in its positions and/or conditions illustrated in FIGS. 6 and 11 of the drawings, that is, that the pointer 166α (FIG. 11) of dial 166 is pointing to the “off” position, the door 140 of oven 143 is closed and, therefore, contacts 163-162 are in their closed conditions, and that contacts 161-162 are closed by bimetallic member 160α.

Under such conditions, none of the previously described or traced electrical circuits are closed. If a housewife or other user of the oven now turns dial 166 to the “bake” cycle of the oven, only coil 158 is energized over its “bake” cycle control circuits and thence over conductor C109 and the set of contacts 153-154 of cycle selector 165 in their closed condition.

If it is desired to initiate a self-cleaning cycle of operation of oven 143, dial 166 is rotated so that its pointer 166α points to the “clean” position of the dial. Such rotation actuates the sets of contacts 150-152, 153-155 and 156-157 of circuit controlling device 165 to their closed conditions. Assuming that the oven door is closed and that the oven temperature is below the temperature at which contacts 161-162 are actuated to their opened condition, the closing of the set of contacts 150-152 completes the previously described second series electrical circuit for the energizing of coil 112. The energization of coil 112 causes retraction of core or plunger 113 into the coil and thereby actuates the parts of the door latching system to their positions shown in FIG. 7. The rotation of cam member 118 towards its rotational position shown in FIG. 7 and corresponding rotation of depending portion 118α of member 118 permits member 125α of switch 125 to move under the force of its own resiliency and, in turn, partially permit plunger or button 1256 of switch 125 to be moved towards its non-depressed position and open the set of contacts 145-147 of switch 125 (FIG. 5) about the time cam member 118 is at its rotational position shown in FIG. 7, that is to say, contacts 145-147 of switch 125 are opened when cam member 110 arrives at a position about halfway in its rotational movement towards its position shown in FIG. 8. If said opening of said set of contacts 145-147 deenergizes coil 112 (see FIG. 11) slightly prior to or when cam member 118 reaches its rotational position shown in FIG. 7, the kinetic energy of cam member 118 rotates such cam member past its halfway rotational position shown in FIG. 7, that is, past its rotational position halfway between the rotational positions of the cam member as shown in FIG. 6, and FIGS. 8 and 9, and spring 128 then completes the rotation of cam member 118 to its position shown in FIGS. 8 and 9.

Similarly, if said set of contacts 145-147 of switch 125 will not open, to deenergize coil 112, until cam member 118 is slightly past its said rotational halfway position shown in FIG. 7, the kinetic energy of cam member 118 causes such further rotation of such cam member, the further rotation being permitted by the previously mentioned hole or slot such as 117α provided in linking or coupling member 117 and through which the previously mentioned pin 115 extends as illustrated in FIGS. 6, 7 and 8 of the drawings. It is pointed out that, for purposes of clarity of illustration, the length of slot 117α is shown in FIGS. 6, 7 and 8 as being somewhat greater than necessary or desirable for optimum operation of the latching system disclosed. It is further pointed out that the hole such as 117α is illustrated as being a slot but it could as well have a circular, eccentric, or other configuration which provides for a limited amount of longitudinal movement of linking or coupling member 117 relative to said pin 115 and, thereby, relative to the right hand end of plunger 113. During the rotation of eccentric or cam member 118 from its position shown in FIG. 6 to its position shown in FIGS. 8 and 9, door latching device or

3.757.084 member 131 is actuated or rotated from its position shown in FIG. 6 to its position shown in FIG. 8 so that the finger portion 131α of member 131 contacts and partially surrounds keeper 133 on door 14® to securely latch such door in its closed position.

In the foregoing described rotation of cam member 118 when such member is at a position at which contacts 145-147 open, the set of contacts 145-146 of switch 125 (FIG. 11) are actuated to their closed condition to prepare the previously described or traced first series electrical circuit for the energization of coil 112. Also, during such rotation of cam member 118, the set of contacts 148-149 are actuated to their closed condition, and both the “bake” and “clean” windings or coils 158 and 159 (FIG. 11) are thereby energized to raise the temperature of oven 143 to a pyrolytic temperature for the self-cleaning cycle of operation of the oven. During such raise in temperature, the set of contacts 161-162 of switch 160 are actuated by bimetallic member 160α to their opened condition when the temperature in the oven exceeds the previously mentioned safe temperature for persons using the oven.

At the completion of the self-cleaning cycle of operation discussed above, dial 166 is rotated so that its pointer 166α points to the “off” position of circuit controlling device or cycle selector 165 and the sets of contacts 150-151 are, thereby, reactuated to their closed condition shown in FIG. 11. At the same time movable contact members 153 and 156 are moved to their open positions shown in FIG. 11 and the energizing circuits for heating coils or windings 158 and 159 are thereby opened to deenergize such coils or windings and permit oven 143 to cool.

When the set of contacts 150-151 are actuated to their closed conditions as mentioned abve, the previously described or traced first series electrical circuit for energizing coil 112 is prepared and, when oven 143 cools sufficiently that the set of contacts 161-162 are actuated to their closed condition by bimetallic member 160α, said first series circuit is completed, coil 112 is again energized and plunger or core 113 is, thereby, retracted into coil 112 to rotate cam member 118 from its rotational position shown in FIGS. 8 and 9 towards its rotational position shown in FIG. 6. When cam member 118 has, during said rotation thereof, rotated to a position about half-way towards its position shown in FIG. 6, plunger 125b of switch 125 is depressed by actuating member 125α of the switch to be partly returned towards its fully depressed position and, at such time, the set of contacts 148-149 are again actuated to their opened condition shown in FIG. 11.

About the time cam member 118 reaches its rotational position shown in FIG. 7, actuating member 125α of switch 125 moves to cause plunger 125b of such switch to be further moved towards its fully depressed position and, at such time, the set of contacts 145-146 of switch 125 are actuated to their opened condition. This oepns the first series circuit for energizing coil 112. Spring 128 may attempt to return the parts of the apparatus to their positions shown in FIGS. 8 and 9 but the kinetic energy of cam member 118 rotates such member past its halfway position shown in FIG. 7, that is, past its rotational position halfway between the rotational position of the cam member shown in FIGS. 8 and 9, and the rotational position of such member shown in FIG. 6, and spring 128 then completes the rotation of said member 118 to its position shown in FIG.

6. During the rotation of cam member 118 from its position shown in FIGS. 8 and 9 to its position shown in FIG. 6, door latching device or member 131 is actuated or rotated from its position shown in FIG. 8 to its posi5 tion shown in FIG. 6 so that door 140 of the oven such as 143 (FIG. 11) is unlatched.

In the foregoing described rotation of cam member 118 from its position shown in FIGS. 8 and 9 to its position shown in FIG. 6, when such cam member is at a 10 position at which contacts 145-146 open, the set of contacts 145-147 of switch 125 (FIG. 11) are actuated to their closed condition to again prepare the previously described or traced second series electrical circuit for the energization of coil 112. Subsequently the 15 apparatus and its parts are again moved, by spring 128, to their positions or conditions shown in FIGS. 6 and 11 of the drawings as previously mentioned.

If, shortly after the initiation of a self-cleaning cycle of operation as previously described, it is decided for 20 some reason to interrupt such cycle and, for such reason, cycle selector or circuit controlling device 165 is returned to its “off” position, the previously described first series electrical circuit for energizing coil 112 will be completed over the set of contacts 150-151 of de25 vice 165 only if the temperature in the oven is still below, or when such temperature drops below, the aforesaid safe temperature which causes bimetallic member 160α (FIG. 11) to actuate contacts 161-162 to their opened condition.

³⁰ Although the door latching system of the invention is illustrated and described as especially useful for controlling the latching and unlatching of the door of a baking oven, it will be readily apparent to those skilled in the art that the inventive door latching system dis³⁵ closed can be readily adapted to the latching and unlatching of doors of other appliances, cabinets etc.

Further, although there is herein shown and described only two embodiments of the latching system of the invention, it will be understood that various ⁴⁰ changes and modifications may be made therein within the spirit and scope of the appended claims without departing from the spirit and purview thereof.