Electrical connecting device

Aug. 4, 1964

J. A. ZIMMERMAN, JR„ ETAL

3,143,385

Filed May 14, 1962

ELECTRICAL CONNECTING DEVICE

Sheets-Sheet i

<img file="US3143385A_D0001.tif" />

J· A. ZIMMERMAN, JR„ ETAL 3,143,385

ELECTRICAL CONNECTING DEVICE 3 Sheets-Sheet 2

Aug. 4, 1964

Filed May 14, 1962

<img file="US3143385A_D0002.tif" />

Aug. 4, 1964

3,143,385

J· A. ZIMMERMAN, JR„ ETAL

ELECTRICAL CONNECTING DEVICE

Filed May 14, 1962

Sheets-Sheet 3

<img file="US3143385A_D0003.tif" />

<img file="US3143385A_D0004.tif" />

<img file="US3143385A_D0005.tif" />

United States Patent Office 3,143,385 ____________ Patented Aug. 4, 1964 withdrawal of the contact from the cavity can not happen. In the drawing:

FIGURE 1 is a perspective view of a type of contact terminal with which the retaining means of the instant invention is adapted to be used.

FIGURE 2 is a perspective view of a contact retaining means in accordance with the invention.

FIGURE 3 is a sectional side view of the retaining means of FIGURE 2 taken along the lines 3—3 of FIGURE 4.

FIGURES 4 and 5 are views taken along the lines 4—4 and 5—5 of FIGURE 3.

FIGURE 6 is a sectional view showing a portion of a cavity in an insulating block which is adapted to receive the retaining means of FIGURE 2.

FIGURES 7 and 8 are views taken along the lines 7__7 and 8—8 of FIGURE 6.

FivrURii 9 is a view similar to FIGURE 6 but showing the retaining means positioned in the cavity.

FIGURE 10 is a view looking into the end of the cavity of FIGURE 9 taken along the lines 10—10 of FIGURE 9.

FIGURES 11, 12 and 13 are views illustrating the πια . ,-, . . . —----- sertion of tne contact of FIGURE 1 into the cavitw these / _tA^^e-1^STi^®1’.^lt2^S_ ^ady,^anta8e?^US-^{t0 have 2S views are not true} sections but are taken along the lines 11—11 of FIGURE 10 in the interest of clarity.

FIGURE 14 is a view illustrating the manner in which the contact is removed from the cavity in the insulating block.

* . FIGURE 15 is a fragmentary cross sectional view showing a. pair of contacts in engagement with each other and showing the retaining means of the instant invention as used with a socket contact; this view is not a true section but is similar to FIGURES 11-13.

A. comm only known type of electrical contact terminal 2 with which the retaining device of the invention is adapted to be used is shown in FIGURE 1 to comnrise a nollow cylindrical crimp portion 4, an intermediate collar 6, and a uniform diameter cylindrical section 8 disposed forwardly of collar 6. A conical inwardly tapering surface 10 is provided forwardly of the section 8 and this conical section terminates in a relatively sheer rearwardly facing shoulder 12 in front of which there, is a further, cylindrical section 14 of the same diameter as the cylindrical section 8. A relatively steep conical surface 16 extends from the cylindrical section 14 to the reduced diameter cylindrical pin end section 18 of the contact. This end section is adapted to be received within complementary socket contact described below. The crimp section 4 is axially bored to receive the stripped end of a conductor 22 to which it may be crimped as is shown at 20 in FIGURE 14.

The complementary socket contact 24, as shown in FIGURE 15, has an axially bored forward end for engagement with the projecting pin portion 18 of the pin contact 2. The intermediate and rearward portions of the ^socket contact have substantially the same external configuration as the pin contact 2 and need not be described in further detail. The corresponding portions Departs of this socket contact are identified by the same rexerence numerals as are used with respect to the pin contact but differentiated by prime marks.

Contacts of the type shown at 2 and 24 are adapted to be. crimped onto the ends of conductors and then in-------_a ------- &amp; plurality of pm contacts 2 are inserted into one block and a like number of socket contacts 24 are inserted in tn another block. When the two blocks are brought into engagement with each other, each of the individual pin contacts in the one block is mated with a socket contact in the other block. An exemplary type of insulating

143 385

ELECTRICAL CONNECTING DEVICE John A. Zimmerman, Jr., Hershey, and Frank B. Miller, Jr., Mechanicsburg, Pa., assignors to AMP incorporated, Harrisburg, Pa.

Filed May 14,1962, Ser. No. 194,369 6 Claims. (CI. 339—217)

This invention relates to electrical connecting devices of the type comprising a contact terminal which is contained within an insulating housing.

A common type of electrical connecting device for disengageably connecting electrical conductors comprises a pair of insulating blocks, each of which has a plurality of contact terminals therein so that when the blocks are engaged with each other the contact terminals of each block are mated with terminals in the other block. One type of contact terminal used in these multi-contact connectors is adapted to be crimped or otherwise secured to the end. of a wire and subsequently inserted into a cavity in the insulating block. With this type of contact terminal, it is necessary to provide a means for retaining the terminal in the insulating block after insertion and preventing its accidental or unauthorized removal from the cavity. ‘ __________ the contact terminal removable from the cavity for purposes of replacement, repair, or to permit changes in circuitry. The instant invention relates to these insertable types of electrical contacts which are used in multi-contact connecting devices.

An object of the invention is to provide an improved retaining means for retaining an electrical contact terminal in a cavity. A further object is to provide an improved retaining means which is disposed within the cavity in the insulating block rather than on the contact. A ³⁵still, further object is to provide a retaining means which positively holds the contact in the cavity and prevents removal excepting when a specialized tool is used for the purpose. A still further object is to provide a substantially fool-proof retaining means which is not prone to ⁴⁰damage in normal usage.

These and other objects of the invention are achieved in a preferred embodiment comprising a split cylindrical sleeve having a pair of forwardly extending arms on one end. The ends of these arms are enlarged and extend ⁴⁵arcuately around the axis of the split sleeve. The lateral edges of the enlarged ends of the arms are inwardly bent towards the sleeve axis to form lips or flanges. The retaining device of the instant invention is intended to be used with an insulating block having a generally cylindri- ⁵⁰cal cavity extending therethrough and in which there are provided a pair of opposed arcuate bosses. The retainer is disposed in the cavity with the edge of the split sleeve disposed against the bosses on one side thereof and with the arms extending between the bosses so that the enlarged ⁵⁵ends of the arms extend circumferentially partially around the cavity at the opposite end of the bosses. The inwardly bent lips on the ends of the arms normally project radially inwardly towards the center of the cavity somewhat beyond the surfaces of the bosses so that when an electrical contact having a circumferential recess therein is positioned in the cavity with the lips or flanges extending into tue recess of the contact, the terminal contact can not be withdrawn by virtue of the wedging action of the flanges or lips of the retainer. Tl____ can, however, be removed from the cavity if the enlarged ends of the arms are spread apart so that the inwardly turned lips or flanges do not project into the circumferential recess in the contact terminal. Spreading of the arms of the retainer can, however, only be achieved by means of a special tool so that accidental removal or

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Ihe contact terminal ^b5 serted into cavities in insulating blocks. Ordinarily MVltv if fho -· ___λ · .-. ' ’ block is shown fragmentarily in FIGURE 14 to comprise a relatively firm section 26 and a relatively yieldable section 28, these two sections being either secured to each other by a suitable adhesive or held against each other by means of a surrounding shell or frame. The relatively hard portion 26 of the insulating block may be of any suitable relatively hard moldable insulating material such as diallyl phthalate while the resilient section 28 may be of a neoprene rubber. The two sections 26, 28 each have openings extending therethrough which to- ; gether define a cavity adapted to receive the pin contact after it has been crimped onto the end of a wire. .

The opening in the relatively firm and hard section 26 of the insulating block is cylindrical as shown at 32 in its forward section which opens into the mating face 30. At the rearward end of this firm section of the insulating block the opening is also cylindrical at 34 but of a diameter somewhat less than the cylindrical section 32, the diameter of the cylindrical section 34 being slightly less than the diameter of the collar 6 of the pin contact and approximately equal to the diameter of the portion 8 of the pin plus two times the metal thickness of the retainer as is apparent from FIGURE 11. A pair of bosses 36 are provided between the two cylindrical j&gt;ortions 34, 32 having arcuate surfaces 42 „.d dcfkxrg forwardly facing shoulder 38 at the end of the cylindrical section 32 and a rearwardly facing shoulder 40 at the end of the cylindrical section 34.

The resilient portions of the composite housing 28Jias a cylindrical opening 44 having a i.-....-----------is substantially equal to the diameter of collar 6 of the contact. Opening 44 has a plurality of inwardly extending collars 46 near its rearward end so that upon insertion, the collars 46 will resiliently press against the surface of the wire to form an environmental seal for the contact. The forward end 45 of the opening 44 is of a reduced diameter thereby to form a stop for the collar 6 and to limit inward movement of the contact.

The retaining means 48 in accordance with the invention (FIGURE 2) comprises a split cylindrical sleeve 50 having a pair of opposed axially forwardly extending arms 52, the ends of which are enlarged at 54 to form arcuate cylindrical segments having the axis of the sleeve 50 as a center. The extreme end portions of the arms are somewhat flared at 56 outwardly to facilitate the removal of a contact from the cavity in a manner described below. The edges of the enlarged ends 54 of the arms which are opposed to the split sleeve 50 are inwardly turned to form radially inwardly directed lips or flanges 60 which flanges folow the arcuate cylindrical configuration of the enlarged end portions 54 of the arms. The inner surfaces of the arms are provided with protuberances 58 in the form of dimples which function as camming means during insertion of the contact into the cavity.

The contact retainer of FIGURE 2 should be dimensioned in accordance with the size of the contact and the cavity in the insulating block section 26. Specifically, the width of the enlarged ends 54 of the arms 52, as measured along their arcuate surfaces, should be slightly less than the distance between the sides of the bosses 46 to permit insertion of the retaining means into the cavity. The diameter of the split sleeve 50 should be slightly less than the diameter of the cylindrical portion 34 of the cavity in the relatively hard insulating block 26.

The retaining means 48 is inserted into the cavity in the block portion 26 prior to assembly of the two block portions 26, 28 to each other. Insertion is accomplished by axially aligning the retainer 48 with the cavity on the righthand side thereof as viewed in FIGURE 6 and with the arms 52 in rotational alignment with the surfaces 42 of 70 the bosses. After aligning the retainer with the cavity in this manner, the retainer is inserted until the enlarged ends are disposed forwardly of the forward shoulder 38 in the cavity. Thereafter the retainer is rotated until the bosses extend into the spaces between the lips 60 and 75

3,143.385 the split sleeve 50 as is shown in FIGURE 9. After such insertion and rotation of the retainer, it can not move leftwardly from the position of FIGURE 9 by virtue of the engagement between the split collar 50 and the rearwardly facing shoulders 40 and rightward movement of the retainer is prevented by the inwardly turned lips which bear against the forwardly facing shoulders 38. It will be noted in this figure that the diameter of the forward cylindrical section 32 of the cavity is substantially greater than the diameter of the frontal end of the retainer at the flared sections 56 so that the retainer can be flexed outwardly as is described below.

After insertion or assembly of the retainer to the forward cavity section 26, the two block sections 26, 28 are secured to each other or clamped together as is described above. Thereafter, the contact, crimped onto the end of a wire, is inserted axially through the resilient section 28 of the cavity and through the retainer 48 in the relatively firm section of the block as shown in FIGURES 20 11-13. As noted above in the description of the figures of the drawing, FIGURES 11—13 are not true longitudinal cross sectional views but are taken along the lines 11—11 of FIGURE 10 and drawn to show a full elevation.

,,_u The purpose of this type of view is to clearly show both and defining a 25 the function of the lips 60 and the function of the dimples 58.

It will be noted from FIGURE 11 that the lips or flanges 60 normally extend inwardly beyond the surfaces uiuosnc _ _________— ...... 42 of the bosses so that when the parts are in the posinormal diameter which 30 tion of FIGURE 11, these lips would tend to prevent insertion of the contact. At this stage, however, the conical surface 16 on the forward end of the contact engages the dimples or bosses 56 so that the arms 52 are cammed outwardly to the position of FIGURE 12. When the parts 35 are in the positions of their figure, the inner edges of flanges 60 are located radially beyond the surfaces 42 of the bosses. Upon further leftward movement of the contact from the position of FIGURE 12 to the position of FIGURE 13, the arms are permitted to return resiliently 40 to their normal position and the bosses 58 will project into the recess defined by the conical surface 10 and the shoulder 12. Thus, when the parts are in their normal positions after insertion of the contact terminal, the lips 60 extend inwardly beyond surfaces 42 of the bosses and are disposed between the shoulders 38 of the bosses and 45 the shoulder 12 of the contact terminal. If the wire to which the contact terminal is attached is pulled, the contact terminal will tend to move rightwardly in FIGURE 13 but v/ill be prevented from movement by the lips 60 which will be wedged between the shoulder 38 and the 50 shoulder 12 of the contact. Withdrawal of the contact from the cavity is thus virtually impossible so that application of extremely high withdrawal force to the conductor would result in destruction of the contact or the retainer rather than in the contact being removed from 55 the cavity.

Forward movement of the contact beyond the position of FIGURE 13 is prevented by the collar 6 which compresses the reduced diameter portion 45 of block 28 against hard portion 26. This compressed material as60 sists in establishing an environmental seal for the contacts.

Where it is desired to remove the contact from the cavity for purposes of repair, replacement, or changing the circuitry, a simple tool comprising a tubular sleeve 65 62 and a plunger 64 is used as shown in FIGURE 14. The tool is inserted into the cavity from the mating face until the bevelled edge of the tube 62 engages the inner surfaces of the flared ends of the contact. The arms 52 are flexed outwardly by the tube so that upon subsequent rightward movement of the plunger 64, the contact is pushed rightwardly from the cavity and past the inwardly directed lips 60 which will have been moved out of the way of the cylindrical contact portion 14.

As is apparent from FIGURE 15, a retaining means in

3,143,385 accordance with the invention functions substantially in the same manner with the socket contact 24 as with the pin contact of FIGURE 1. The forward end 25 of the socket contact is slightly tapered to facilitate insertion and to exert a camming action on the dimple 58 of the retainer.

A salient advantage of the invention is that the contacts can be retained in their cavities positively and securely in a manner such that accidental removal is virtually impossible although intentional removal when desired can be accomplished with relative ease and without damage to the contacts or to the retainer. Additionally, Since the retaining means is contained within the cavity, the possibility of damage thereto is avoided as is the case where the retaining means are provided on the contact.

Changes in construction will occur to those skilled in the art.and various apparently different modifications and embodiments may be made without departing from the scope of the invention. The matter set forth in the foregoing description and accompanying drawings is offered 20 oy way of illustration only. The actual scope of the invention, is intended to be defined in the following claims when viewed in their proper perspective against the nrior art.