US3182280A - Protection of electrical connector contact pins - Google Patents

Description

y 4, 1965 F. x. DAUT ETAL 3,182,280

PROTECTION OF ELECTRICAL CONNECTOR CONTACT PINS I Filed April 19, 1963 2 Sheets-Sheet 1 Fig. 3 V/l/l nvvnvrons Francis X. 0041/ Ralph 0. Work M4 aw/W A Homey y 4, 1965 F. x. DAUT ETAL 3,182,280

PROTECTION OF ELECTRICAL CONNECTOR CONTACT PINS Filed April 19, 1963 2 Sheets-Sheet 2 29 r 9 Fig. 5 w,,,,/// /4271 J x, WWII/14171,]?

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if "n5 40 38 Fig 7 42 gi l/111 39 Wm 50 INVENTORS 59 Francis X. 000/ 53 47 57 Ralph 0. Work 8 XMGIW Attorney United States Patent 3,182,280 PROTECTION OF E ECTRICAL CONNECTOR CONTACT PINS Francis X. Daut and Ralph 0. Work, Albuquerque, N. Mex, assignors, by mesne assignments, to the United States of America as represented by the United States Atomic Energy Commission Filed Apr. 19, 1963, Ser. No. 274,363 '1 Claim. (Cl. 339-66) The present invention relates generally to electrical connectors and more particularly to protecting contact pins in electrical connectors.

In the past, contact pins have often been sufficiently bent or splayed out of alignment so as to prevent proper engagement with pin receiving sockets in mating connector components. This problem of improperly mated connectors is of growing concern in the electronic industry, since a bent or splayed contact pin may readily cause the failure of or decrease the reliability of an entire electronic system.

Normally, contact pins in electrical connector plugs or receptacles are mounted in an insulating insert in such a manner that a considerable length of each contact pin extends beyond the insert so as to facilitate mating with suitable pin receiving sockets in another connector portion. This free length of the pin is relatively unprotected, thus leaving it vulnerable to damage by being bent during connector fabrication, handling, storage and while the connector is being readied for connection to test equipment. Bent pins are generally caused by careless handling of the connectors and improper mating procedures and are more commonly found on connectors with glass seals or rigid inserts. When a connector pin becomes bent, such as shown in the accompanying drawings, it is no longer parallel to the major axis of the connector because of a bend in the pin somewhere between the engaging end of the pin and the solder cup end. The non-parallelism is so great that some part of the exposed or free-length of the pin is not within the positional tolerance specified by the connector manufacturer. However, part. of the exposed length of the pin is usually parallel to the major axis of the connector while the remaining part of the pin is non-parallel.

The exposed length of the pin, when not held in its correct position also facilitates the occurrence of another undesirable pin orientation during connector fabrication or processing. This problem is referred to as pin-splaying which is a straight pin that is not parallel to the major axis of the connector such as shown in the accompanying drawings. The splayed pin is not normally bent and has essentially the same extent of non-parallelism as the bent pin. Splayed pins are common to connectors with resilient inserts (e.g., rubber of about 75-80 durometer hardness) and are caused by improper connector processing methods, i.e., when lead wires are wrapped or attached to solder cups on the pins, or while cable assemblies are being molded or potted to the connector. Cable assemblies with sharp bends next to the connector and those which require high temperature or pressure molding processes are especially vulnerable.

Normally, bent and splayed pins occur in connectors using gauge (.040 inch) pins or less, though connectors with larger pins such as 16 gauge (.062 inch) are also susceptible. Bent and splayed'pins usually do not align with the pin receiving sockets in the mating connector portion, thus causing the pins to not only damage the insert in the mating connector by piercing and'rupturing the insert as illustrated in the drawings, but oftentimes prevent the establishment of an electrical path through the connector. In fact, it is possible that a connector may be mated without apparent ditficulty only to later 3,182,280 Patented May 4, 1965 adjoining socket in the insert.

It is, therefore, a principal object of the present invention to provide protecting and fixture means for maintaining proper alignment of connector contact pins from the connector origin through subsequent handling, storage and processing to ultimate connector use.

Another object of the present invention is to provide a rigid, non-conducting insert which is adapted to engage and support essentially the full exposed length of electrical connector contact pins and thereby prevent bending and splaying thereof.

A further object of the present invention is to provide means for holding connector contact pins in position during connector processing, i.e., when wires of cable assemblies are being attached to contact pin solder cups and subsequently wrapped, and/ or while cable assemblies are being molded or potted to the connector.

Other and further objects of the invention will be obvious upon an understanding of the illustrative embodiments about to be described, or will be indicated in the appended claim, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice.

Preferred embodiments of the invention have been chosen for purposes of illustration and description. The preferred embodiments illustrated are not intended to be exhaustive nor to limit the invention to the precise forms disclosed. They are chosen and described in order to best explain the principles of the intention and their application in practical use to thereby enable others skilled in the art to best utilize the invention in various embodiments and modifications as are best adapted to the particular use contemplated.

In the accompanying drawings:

FIG. 1 shows a conventional electrical connector component with bent and splayed contact pins;

FIG. 2 shows another conventional electrical connect-or component illustrating the improper coupling and insert damage caused by bent or splayed contact pins of a mating connector component;

FIG. 3 shows one embodiment of a contact pin protector of the present invention adapted to protect con-tact pins in a plug portion of an electrical connector;

FIG. 4 is a sectional view showing the embodiment of FIG. 3 prior to mating with a plug portion of an electrical connector;

FIG. 5 is a sectional view similar to FIG. 4 but showing the contact pin protector of the present invention in its proper mating position with wrapped lead wires of a cable assembly soldered to the contact pins;

FIG. 6 is a sectional view similar to FIG. 5 showing an encapsulated or potted cable assembly;

FIG. 7 shows another embodiment of a contact pin indicated by numeral 10 have been bent out of alignment by careless handling or improper mating procedures while the contact pins indicated by numeral 11 have been splayed during the connector processing.

When coupling an electrical connector porno-neontaining bent or splayed contact pins to a contact pin receiving connector portion such as shown in FIG. 2, the misaligned contact pins may engage the insulating insert adjacent the pin receiving sockets and thereby damage the insert. The damage to the insert may result in the piercing or rupturing thereof as indicated by numerals 12 and 13 respectively, so as to prevent the proper mating of the contact pins with the sockets, which may in some instances result in preventing the connector from performing its intended function.

Thus, as briefly mentioned above, the present invention contemplates providing pin-bearing connector receptacles and plugs with pin protecting and fixture caps capable of being secured to the connector in such a manner that essentially the full free-length of each individual pin is rigidly held in its proper position by an insert portion of the cap until such time the connectors are to be tested or attached to a mating connector portion.

Described more particularly and with reference to FIGS. 3 to 8 of the drawings, one embodiment of the present invention comprises an electrical plug connector protective cap and fixture generally indicated at 16 in FIG. 3 adapted for use with connectors having bayonettype locks. The cap 16 may be made of any suitable rigid nonconducting material, such as, for example, diallyl phthalate plastic or neoprene rubber, which may be molded or otherwise formed into the desired shape. The cap shown comprises a generally disk-shaped portion 17 of a diameter greater than the connector body to which the cap is to be attached and a pair of coaxially arranged body portions 18 and 19 extending from a central portion of the portion 17 and integral therewith. The disk-shaped portion 17 is shown provided with lugs 20 spaced about its circumference for enabling the cap 16 to be readily mated to a connector plug. The body portion 18 is preferably solid and includes therein a plurality of openings or sockets 21 each to receive a contact pin 22 of a mating plug connector (FIG. 4). These sockets 21 may be provided in any suitable manner such as by molding or drilling and are preferably held within tolerances which enable a good interfit with the pins 22 without excessive play therebetween. For example, desirable socket di mensions for a 20 gauge pin (.040 inch) would be about .044 inch in diameter and of a length slightly greater than the exposed length of the pin 22. Locations of the sockets 21 are preferably held to about .005 positional tolerances on the diameter and, of course, are dependent upon the location and size of the pins in the plug connector, thus necessitating the use of a particular protective cap for a particular array and size of pins.

The plug connector may be of any suitable known construction, for example, a bayonet-type lock connector. The plug connector shown in FIGS. 4-6 may comprise an annular metal shell 24 with resilient, or sometimes rigid, insulating insert 25 afiixed therein. The insert 25 is disposed in such a location within the shell 24 that a contact pin 22 or a plurality of such pins extending through the insert have a considerable unsupported length (about 0.250 inch for both the 16 and 20 gauge pins) and yet are still confined within the shell. The ends of the pins extending through the insert 25 in the opposite direction may be provided with conventional solder cups 26 for facilitating the attachment of lead wires 27 (FIG. by soldering or the like. A rotatable sleeve 29 having sloping grooves 30 in the inner surface thereof may be positioned about the shell 24 for providing a portion of the bayonet-type lock between the mating connector portions and in the instant case with the pin protecting cap 16.

To mate and lock the protecting cap 16 to the plug connector, the body portion 19 of the cap 16 is preferably annular in form and provided with projections 32 on the outer surface thereof for reception in the sleeve grooves 30. This body portion 19 is radially spaced from the central body portion 18 for providing an annular groove 33 therebetween for receiving a leading portion of the shell 24. In order to assure that the sockets 21 and the pins 22 are correctly aligned prior to attaching the cap 16 to the connector, the body portion 19 may be of a length slightly greater than the central portion 18 and be provided in the inner surface thereof with a number of axially extending keyways or slots 35 (FIG. 3) for receiving a corresponding arrangement of keys or projections 36 on the outer surface of the connector shell 24. Thus, by mating the keys with the keyways, the sockets 21 in cap 16 are properly oriented with the pins 22 prior to their engagement. When the cap 16 is positioned and locked in place by the sleeve 29 (FIGS. 5 and 6), the leading edge of the body portion 18 very closely approaches the face of the insert 25 and facilitates the encircling and support of essentially the entire exposed length of each pin 22. The insert 25, particularly when it is of the resilient type, may be provided with a ringlike ridge 31 about the circumference of its face to pro vide a sealing arrangement with the leading edge of the body portion 18 for preventing foreign matter from reaching the contact pins. Also, to enhance this sealing arrangement, a washer 28 of a suitable material such as silicone or the like may be disposed in the annular groove 33 and be engaged by the leading edge of the shell 24.

Processing or fabricating the connector by attaching lead wires of a cable assembly to the pins, wrapping them, and subsequentially potting the cable assembly thereto, may be readily attained in connectors having resilient inserts and with elimination of the heretofore known problem of pin splaying by initially positioning and locking a suitable protective cap and fixture 16 in place over the free-length of the pins 22. The wires 27 may then be soldered to the pin soldering cups in a prescribed manner and thereafter wrapped by suitable binding material 34 into a cable bundle of desirable dimensions (FIG. 5). As the wires are being wrapped the tendency of the pins to splay as the wrapping material 34 bears on the wires is alleviated by the protective cap 16. With the protective cap and fixture 16 still in position, a suitable mold or boot (not shown) may be placed about the cable assembly and a portion of the connector so that a suitable potting material 37, such as, for example, polyurethane or the like, may be molded or otherwise placed about the cable assembly and the connector to hold the cable assembly in a desired orientation with respect to the connector (FIG. 6). With the cap 16 in place, normal shrinkage of the potting material 37 can not splay the pins from their intended positions. After the molding or potting step is completed the wires are held in place so that removal of the protective cap will essentially eliminate pin splaying; however, the protective cap is not normally removed at this time, but remains attached to the connector until such time the connector is to be used; e.g., prior to testing or mating with another connector portion.

FIG. 7 shows another embodiment of the present inven tion particularly adapted for use with a contact pin containing connector receptacle. This embodiment, like the protective cap and fixture 16 of FIGS. 3 to 6, is shown provided with a bayonet-type lock for attachment to a connector portion having such a locking arrangement.

The protective cap and fixture generally indicated at 38 (FIGS. 7 and 8) comprises an insulating body 39 of a material similar to that of cap 16 and includes a plurality of pin receiving openings or sockets 40 extending axially thereinto to a depth slightly greater than the exposed or unsupported length of contact pins 42 in a receptacle connector portion 43 (FIG. 8). The outer surface of the insulating body 39 may be provided with an encircling flange 44 and a recess 45 axially spaced from the flange. A rotatable connector locking sleeve 46 having sloping projection receiving grooves 47 on the inner surface there of and an inwardly disposed lip 49 on one end thereof is adapted to encircle the insulating body 39 and abut against the insulating body flange 44. With the sleeve 46 in position over the body '39 a suitable locking ring 50 may be placed in the recess 45 to hold the sleeve 46 in place. While the sleeve 46 is preferably made of metal to insure a positive connection with the connector receptacle it will appear clear that it may be made of any suitable material such as plastic, hard rubber or the like.

The receptacle connector portion 43, which is adapted to receive the protective cap and fixture 38 as shown in FIG. 8, may comprise a metal shell 51 With a rigid or resilient contact pin bearing insert 52 therein and a plurality of projections 53 on the outer surface thereof adapted to be received in the sloping grooves 47 of the sleeve 46 for locking the cap to the connector. Insert 52, like the insert in the plug connector of FIGS. 4-6, holds the pins 42 in such a manner that a considerable length of the pins remains unsupported. Thus, the insulated body 39 is adapted to fit into the connector shell 51 until it nearly abuts against the leading face of the insert 52 so as to receive essentially the entire unsupported length of each contact pin. In order to assure that a secure coupling is maintained between the cap 38 and the connector portion 43, a suitable spring 57 such as a wave spring or the like may be disposed between the flange 44 and the lip 4%. This spring maintains the coupling by forcing the projections 53 into suitable notches (not shown) in the walls of the recesses 47.

To assure that the sockets in the protecting cap 38 are properly aligned with the pins in the receptacle a plurality of axially extending projections or keys d4 may be placed about the surface of the insulating body 39 for reception in suitable keyways or slots 55 in the inner surface of the connector shell 51. To align the keys and keyways prior to the pin engagement With the sockets, the leading edge of the insulating body 39 may be provided with a small ring-like portion or rim 56 which is integral with the insulating body and which extends beyond the ends of the keys 54 so that the body 39 may be easily rotated until the keys and keyways match. A suitable sealing arrangement between the cap and the insert may be attained by providing the face of the insert with a ring-like ridge 58 so that as the cap contacts with the insert it slightly deforms the ring and provides the seal. The insert may also be provided with a small periph eral recess 59 in its face about the ridge 58 to receive the cap rim 56. This recess 5? may be provided with a deformable Washer t? of a suitable material such as silicone or the like to enhance the aforementioned seal between the cap and the insert.

The protective cap and fixture 33 may be used in connector processing and fabrication in a manner similar to the protective cap and fixture 16. Also the dimensional tolerances of the sockets 40 are similar to sockets 21 of cap 16 for similarly sized contact pins. While the keys 54 and the keys 36 of the embodiment of FIGS. 4-6 are shown extending a substantial length of the insulating body 359 and the body portion 19 respectively, it will appear clear that keys or projections of any suitable length may be used.

Both protecting cap 16 and cap 38 may be provided with projections or other means on the outer surfaces thereof for facilitating the alignment of the cap sockets with the connector pins and for aiding in connector processing, e.g., fabricating the connector cable assembly. For example, cap 16 may be provided with a projection 61 011 the disk-shaped portion 17 that is in alignment with the largest keyway, while cap 38 may be provided with a small projection 62 on the back of the body portion 39 that is in alignment with the largest key. The caps 15 and 38 are preferably constructed with such dimen sions that a close fit is attained between the walls of the caps and the walls of the pin bearing connector. While the protective caps and fixtures are shown as being used with connectors havin a bayonet-type locking arrangement, it Will appear clear that the protecitivecap and fixture of the present invention may be used with any pin bearing connector configuration regardless of locking features. Furthermore, the present invention is adaptable for use with electrical connectors of other shapes such as square, rectangular, etc.

It will be seen that the present invention provides a relatively simple and inexpensive solution to the splayed and bent connector pin problems that have heretofore been of great concern because of their frequent appearance. The protective caps engage and position the contact pins with respect to the same datums as will be engaged by a mating connector, i.e., the caps employ cooperating projections and grooves that are the same as will be used on mating connectors to retain connector halves together. Also, the present invention provides an end cap feature for preventing foreign matter from entering the connectors, which is particularly advantageous for field use. The pin protecting caps are readily re-useable and conveniently serve as gauges for determining if the connector portions are matable prior to their assembly.

As various changes may be made in the form, construction and arrangement of the parts herein without departing from the spirit and scope of the invention and without sacrificing any of of'its advantages, it is to be understood that all matter herein is to be interpreted as illustrative and not in a limiting sense.

We claim:

A device for detecting inaccurately positioned pins and protecting accurately positioned pins of an electrical connector, comprising an end cap member having a main body formed of a single piece of rigid plastic material with a perforate end and an imperforate end, said perforate end having a planar face and defined by a plurality of mutually parallel sockets penetrating said face and terminating at a location intermediate said ends, each of said sockets being of uniform diameter from said face throughout essentially the entire socket length and the diameters corresponding closely to the diameters of said pins for the Walls of plastic material defining said sockets to closely envelop said pins throughout substantially their entire exposed lengths, and said body having an annular laterally outwardly projecting flange integral with said body and disposed intermediate said ends thereof, connecting means to secure said device to a said connector including a portion relatively rotatable with respect to said body and including means overlapping said iiange to limit axial movement of said portion and including another portion laterally spaced from said body de fining a groove therebetween for housing an annular part of a said connector, guide means ali ning said pins with said sockets comprising a plurality of keys of said plastic material each integral with and projecting from an outer surface of said body with an end of each key terminating in a plane substantially common with said planar face with each key to mate with a complementary keyway in the annular part of a said connector, one of said keys being of larger cross-sectional dimension than the others of said keys for mating with a keyway of corresponding cross-sectional dimension to insure orientation of said sockets with said pins, an annular integral ridge extending about said planar face and axially projecting away from said flange terminating in a plane spaced from and overlying both said planar face and the ends of said keys and with said ridge having a diameter intermediate that of the annular part of a said connector and that of a dielectric insert housing said pins in a said connector wherein said ridge initially cooperates with said keys to facilitate alignment of the latter with said keyways and thereafter projects past a leading surface of the dielectric insert to engage a deformable sealing means disposed between the insert and the annular part of a said connector, and an indicator projection integral with and on said impcrforate end aligned with said one key for indicating and facilitating alignment of said one key with said one keyway.

(References on following page) References Qited by the Examiner UNITED STATES PATENTS Wiley 33938 X Miller 339-38 Winer 33938 X Uline 339-60 Chouljian 33966 Obenschain et a1 339218 X 8 Chapman et a1 339218 Elwell 33936 Quackenbush 264-277 Lieberman 264-274 Hennessey et a1 339-90 X FOREIGN PATENTS Great Britain.

JOSEPH D. SEERS, Primary Examiner.

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