US2751568A - Wire centering means for pin-type insulation-piercing connectors - Google Patents

Description

June 19, 1956 v R DESPARD 2,751,568

WIRE CENTERINC MEANS FOR PIN-TYPE INSULATION PIERCING CONNECTORS Filed Nov. 15, 1954 IN V EN TOR.

ICTOR R. 13,218 PA D f QTTORNEYS United States Patent i WIRE CENTERING MEANS FOR PIN-TYPE INSULATION-PIERCING CONNECTORS- Victor R. Despard, Syracuse, N. Y., assignor to Pass & %eymour, lnc., Syracuse, N. Y., a corporation of New ork Application November 15, 1954, Serial No. 468,783 2 Claims. (Cl. 339-99 This invention relates to electrical connectors and more particularly to wire centering means for pin-type, insulation piercing connectors whereby insulated wires of different overall diameter may be effectively centrally pierced to insure adequate contact between the conductor and the contact pin. It is a general object of the present invention to provide wire centering means for pin-type insulation piercing connectors to insure pin centering in the stranded conductor in-spite of variations in insulation thickness or overall wire diameters.

An important object of the invention resides in the provision of means in the insulated Wire receiving channel capable of centering therein such wire of an outside diameter less than channel width to insure penetration of the connector pin into the conductor thereof.

Another important object of the invention resides in the arrangement of the wire centering means whereby it may readily be'embedded in the insulation of a wire of an overall diameter to closely fit the channel by the simple operation of pressing the wire into the channel and over the connector pin.

A further important object of the invention consists in arranging the centering means as fins or blades extending from both walls of the channel at opposite sides of the connector pin and parallel to the axis thereof whereby they are non-interfering with the operation of molding the channels into electrical apparatus.

Other and further objects of the invention will be more apparent to those skilled in the art upon a consideration of the accompanying drawing and following specification wherein is disclosed a single exemplary embodiment of the invention with the understanding that such modifications maybe made therein as fall within the scope of the appended claims without departing from the spirit of the invention.

In said drawings:

. Fig. 1 is a side elevation of a so-called pin-typeconhector. lampholder or socket with the cap removed and conductors of two diameters positioned one to be entered into each channel where the connector pins are located; 2 Fig.2 is a longitudinal central section through such a socket in'fully assembled form;

Fig. 3 is a top plan view of the channelled end of the body portion of such a socket showing the conductor centering means in end elevation and engaging dotted line conductor insulation of two difierent diameters; and

Fig. 4 is a plan view of the under surface of the socket cap.

Electric light sockets and other wiring equipment using normal voltages and low currents are often equipped with what is known as pin-type, insulation piercing connectors, permitting quick assembly of the equipment to conductors. Such devices are particularly useful in assembling outdoor light strings for ornamentation, advertising or other purposes and for this the socket construction is provided with a pair of transverse, parallel slots each with a connector pin projecting from the bottom thereof, An in- 2,751 ,568 Patented June 19, 1956 ice sulated, stranded conductor can be pressed into each slot and held there by a subsequently applied cap. The pin in the bottom of each slot penetrates the conductor insulation and electrically engages the strands of the con-v ductor so that electrical connection is made between the socket elements and the wires.

For a number of years, before the advent of satisfactory synthetic plastics having good weather resistant qualities and generally higher insulating properties than the earlier known materials, the external diameters of low voltage lighting conductors was usually controlled by the wire size and the so-called waterproof or weather resistant cover was of rubber under tarred braid. The overall diameter was substantially standardized for the most used wire gauges of 12 and 14. This made it simple to size the socket slots for a close fit with the walls of the conductor insulation to substantially insure the centering of the connector pin in the stranded conductors.

Lately, however, synthetic plastics of high insulating and weather resisting properties have become common as single coat insulators for stranded or solid wire, and because of their much higher dielectric strength the thickness of the insulation is considerably less than that of the so-called weather resistant two layer coatings. This results in a conductor with much smaller overall diameter. Since neither form of coating is universal a need arose for means to center the conductor over the pin connector when introducing it into the slot to insure centralization of the latter in the conductor, for otherwise it would be possible to introduce the smaller diameter wire Without making adequate electrical contact. The more obvious solution, i. e., of making sockets with channels of different widths for difierent conductors, is not the economical one, and the present invention provides centering means capable of functioning with a relatively wide range of conductor diameters, so that only one standardized channel width is necessary.

Referring now to the drawings, there is illustrated a more or less conventional form of pin type lampholder or socket to which the present invention is applied. Such socket may include a molded cup-like plastic shell 10 to house the screw shell contact 11 exposed through the flared open end 12 of the device. The upper end of part 10 is closed by a thick integral molded portion, and the base of the screw shell is secured thereto by a rivet 13 passing through the base and a portion ofthe cup closure and headed over at 14 against the bottom of the screwshell. The opposite end of the rivet has a head 15 seated in the bottom of a circular well 16 in the cup closure. Well 16 intersects at a right angle one of the wire receiving channels 17 extending in parallel relation transversely across the shell-cup closure end as seen in Fig. 3.

A similar pin 18 secures the center socket contact 19 against the bottom wall of the housing at a portion where the screw shell is cut away as at 20. The head 21 of this pin is positioned engaging the bottom of well 22 in the other channel 17. Formed integral with each of the pin heads 15 and 21 is a long tapered connector pin 22 projecting out of the well housing the heads 15 and 21 and a substantial distance into the wire channels 17.

As viewed in end elevation in Fig. 1 the wire channels are each formed by spaced parallel side walls 25, the distance between which is substantially that of the diameter of the largest insulated wire to be received therein. These walls are joined at the bottom by an arcuate trough 26 of semi-circular cross-section and the depth from the bottom of the arcuate portion of the trough to the top surface 27 of the base is greater than the width between the walls 25.

A cap 30 is provided to cover over the channels and hold the wires firmly in position therein. It is formed of molded insulating material to a hollow, low, dome-like confiuration,hacingahatzannular border 31 facing and engaging the surface 27 and a thick center or hub Portion 32 into which is molded a threaded metal sleeve 33 whereby the cap may be secured onto the threaded stem 34 extending axially through the. base? of the socket with the head 35 recessed in the bottom thereof: beneath the center contact and the whole being secured: in position byanut: 36- engagingthe bottom of an elongated channel 37-. between the; wire: channels, best seen in Fig.2 3'.

The under surface of the: cap is. shown in Fig. 4 and between the peripheral surface 31 and the center core 32 is an. annular wall; 39 projecting: below the surface 31 andthaving such diameters that it is: received in. the wire troughs 17 just above the tips of the pins 23.. Toaccommodate it in other portions ofthebase. appropriate 'circular. grooves 4.0 mi provided between. channels 17 and 37.

'Ihe--.depthi of .the latter channek is adequate to accommodate39 whereit. crossesthe same: at the. two ends.

. Torwire suclr a-.device. the cap is removed and a pair of. conductors is arranged one above each. channel; and pressed interposition therein to: cause the pins to penetrate the insulation. and enter between the conductor strands; The cap is then threaded: on so. that thewall 39 forces the wires over the: pins. and against the bottoms ofi their channels tamake: and maintain the. conductoreng'agement.

, -ij'iilie wiretchannels; aremade: of z'r'di'mension to suit the larger type of: insulation used on thelwlire to he received therein and; their walls; would. naturally center such an insulated; conductor over the pin; If, however, a thinner wallediinsnlation is: used, the'overalldiameter will: be as show-n CEUSSrSBCfiOfl in the exploded: Fig; 1 at 59 as compared with: the; larger dimension insulation shown at 51. Ia-is "obvious; if such small diameter wires were pressed info'the channels they could pass between the sloping side of the pin and the side wall of the channel without the pin penetrating the insulation.

Topreventl such anoccurrence each. flat channel wall 'is provided with'two. inwardly projecting, blade-like ribs 01Tfi1lS: 553WhlCh are located at the junctions of these. walls and: theawellsinz' which the pins are sunk (see Fig; 3

With the construction just described the socket or other electrical, fitting (since the. socket. has. been used. in

' therein for. receiving an insulated wire usable with the connector, a tapering conductive pin extending trans.

versely of said channel from the bottom of said U, fins of insulation arranged in pairs on opposite sides of the pin;

the fins of a pair extending from opposite, walls. of. the

channel toward the other to center an insulated wire of less diameter than channel width over said pin to insure penetration oft-he conductor when the wire is pressed in the channel and to deform and enter the insulation of' awire ofoverall diameter greater than the spacing of theedges of a pair of fins, and said pairs of fins beingspaced apart" longitudinally of the channel not substantially more than the Width thereof.

These ribs are thin and knife-like. and. have their edges 7 parallelto the'axes, of the pins, as. clearly seen in 'Figs. 1,

2 and: 3. .1 The spacing between. the edges of opposed ribs is substantially equal to the diameter of the small insulation conductor 50,. whereby the conductors therein will be: engaged thereby and centered over the pins: the

' same: as the larger ones, although theymay: be loose in the remainder-.of'the. channel, The fins or ribs-are relatively' thin in the directionof the length of the'channel's and; their outer. corners are rounded or 'chamfered; as

shown, and. are readily forcedinto the insulation of the larger. diameterconductors to embed themselves therein andnot seriously interfere with the introduction of'these conductonsJinto their channels and over the pins. As a matter: of: factywhen used" with the large conductors these 'fins act somewhat. in the sense of' a strainrelief device transmitting the load of the socket and its lamp-to some extent tot-the. insulation: parts of the conductor and socket and thereby relieving the conductor parts of alarge portion ofthe strain.

, 2'. A pin type connector adapted to radially penetrate i the insulation and engage the stranded conductors of a single insulated wire selected from among such wires of circular-configuration having various overall diameters, comprising in combination, a block of insulation having a U-shaped channel therein dimensionedfor receiving an insulated wire usable with the connector, 2. long tapering conductive pin mounted in said block and extending into said channel from the bottom of said U, four fins'of' insulation arranged in pairs on opposite sides of the pin, the fins of a pair extending fromopposite'wallsof the channel toward each other to center an insulated wireof lessdiamcter than channel width over said pinto insure penetration of the conductor when the wire ispressed into the channel and beingof thin'blade-like character to readily deform and enter the insulation of a wire of overall diameter greater than the spacing of the edges of a pair-of fins which are substantially parallel to the axis of the pin, said .pair of fins'being spaced apart longitudinally of the channel not more thanthe width thereof,

and means to force and hold a conductor over said pin. 7 7

References Cited in the tile of this patent UNITED STATES PATENTS '1',-s49,s4s McNeil Mar. rs, r932 1,976,492 Greene Apr; 16, I935. 1,997,716 Brooks et al. Apr. 16', 19:35 2,060,115 Pollock "Now 10; 1936 2 ,333,266 Miller NovQZ, 1943 2,353,882 Despard July 18,1944

7 FOREIGN PATENTS. I

"61537371 7 Great Britain Jan. 11,5194

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