US3125392A - Spring-wire - Google Patents

Description

March 17, 1964 P. H. WINTER 3,125,392

SPRING-WIRE, DUAL-GIPPER FOR coNDucToRs;vv

Filed April 2, 1.962

vPAUL H. WINTER ATTO York

Fiied Apr. 2, 1962, Ser. No. 184,671 7 Claims. (Cl. 339-95) This invention relates to electric wiring devices and more particularly to a spring-wire, dual-gripper for conductors.

It is a general object of the present invention to provide a novel and improved gripper for two conductors formed from a single length of spring-wire arranged for cooperation with a stationary terminal plate.

An important object of the invention resides in the arrangement and cooperation of a dual-gripper of spring wire with a terminal plate which holds the former in position in a formed recess in a moulded insulation part without the need for any additional fastening or cover means.

Another important object of the invention consists in the provision of access directly to the gripper springs individually by a common tool to alone release either conductor gripped thereby.

An important feature of the invention consists in holding the dual spring in position by having the bottom of the terminal plate engage and hold its transverse central portion against outward movement.

Other and further objects and features of the invention will be more apparent to those skilled in the art after a consideration of the following specicationfand the-accompanying drawing, wherein is disclosed a single examplary embodiment of the invention, with the understanding that such changes and modifications may be made therein as fall within the scope of the appended claims without departing from the spirit of the invention.

In said drawing:

FIGURE l is a bottom plan View of a porcelain lightingxture equipped iwth two spring-wire, dual-grippers constructed in accordance with the present invention;

FIGURE 2 is a fragmentary longitudinal section, on a larger scale taken therethrough-on line 2-2 of FiG- URE l;

FIGURE 3 is a perspective View, on the larger scale, of the spring-wire, dual-gripper and its cooperating terminal plate removed from the insulating ixture base;

FIGURE 4 is a view similar to FIGURE 2, but illustrating a conductor in position held by one part of the gripper, and with the terminal plate shown in longitudinal section between the wings thereon;

FIGURE 5 is a view similar to FIGURE 4,.but showing the gripper tiexed by a tool to release the vconductor for withdrawal; and

FIGURE 6 is a fragmentary View, like FIGURE l, on an enlarged scale, showing in dot and dash lines one complete gripper assembly in position in a recess in a mouded insulation base.

The invention is illustrated for convenience in connection with a moulded, box-mounting type of lamp holder, commonly referred to as a boxcover socket or porcelain light fixtureV for bathroom, kitchen and similar uses, but obviously this is merely by way of illustration for the terminal device is capable of use in many other positions Where sufiicient housing depth, in moulded insulated material, is available to accommodate it.

Referring now to the drawing and tirst to FIGURES 1 and 2, it will be seen that the wiring device comprises a moulded base or housing 10, suitably perforated at 11- 11 for the reception of mounting or fastening screws which secure it to act as a cover for a junction or rixture box of the circular or octagonal type. The fragmentary United States Patent O thetic resin.

3,125,392 Patented Mar. -17, 1964 ICC section of FIGURE 2 illustrates the socket sleeve 12 projecting integrally and centrally from the front face, of the circular base shown in FIGURE l, and formed of `suitable insulating material such as porcelain or syn- A conventional metal screw shell 13 is mounted in the central recess thereof, and secured in Iposition by means of a rivet 14, and is illustrative of one of two contacts each of which is accommodated by a dual-gripper for-conductors, formed-in accordance with lthe principal part of the present invention.

The back wall V15 of the wiring device is substantially fiat, as shown to iit against a wall surface, and is provided with various lightening pockets 16 and with two recesses 18 spaced somewhat less than 180 apart to accommodate the wire grippers for conductors supplying current to the dual `wire gripper.

The dual wire grippers and their essential equipment, arranged in the recesses 18, are identical in construction and the` description of one will su'ice for both. As seen in FIGURE l` a terminal plate 2t) is provided against the inner wall of the recess 18, and comprises, as seen inthe `other figures, a flat plate 21 having side wings 22 parallel to each other and bent up substantially at right angles to the flat surfaces of the plate 21. A tang 23 is bent at right yangles from the upper edge of the plate, is somewhat narrower than the rest of the plateand is perforated as at A24 to accommodate a rivet such as 14 shown headed over in FiGURE 2 whereby the terminal plate is placed in elec- Vtrical communication with the socket contact 13. The Vother wire gripping device has its tang connected to a central contact, not shown, for the socket. The tang 23 is accommodated in a shallow recess 25 in the back wall t ofthe wiring device, thus keeping all parts below the liat surface thereof.

The recess 18 is of a complex shape as best seen in FIGURE 6 considered along with FIGURE 2. Therecess lincludes a pair of parallel grooves 26 normal to 1 the face of the plate 2l and having their outer walls 27 substantially continuations of the inner faces of the wings 122. The plate 2l is accommodated in a transverse channel v23'which connects together the notches or grooves 26. The minimum dimension of the channel 28, i.e., measured in the direction of length of the notches 26 Lis only slightly greater than the thickness of the plate 21 to readily accommodate it but to leave between it and .the face of the abutment 29 between the notches 26, a space 29 less than the thickness of the plate and certainly less thanthe diameter of the gripping wire which will be later described.

The notches 26, as best seen in FIGURES 2 and 4, open out through the back wall of the wiring device, having substantially parallel side walls and an irregular bottom wall composed of the wall 39 almost normal to the flat surface of the back of the wiring device, the wall 31 extending at an angle of approximately 45 to the axis through the socket of the wiring device, and a bottom Wall 32 normal to said axis. A portion 33 slightly elevated above this bottom wall 32 lies only beneath the lower edge of plate 21, which it will be appreciated is held in position by the tang 23 and the rivet 14. Behind the plate 21 the rear wall of the channel may be inclined to provide draft for the process of molding the device, and, this is true of the other walls which are more nearly normal to the surface of the back of the wiring device.

As seen in FIGURES l and 6 the transverse channel 2S extends laterally beyond each of the notches Z6 and is Zia thickened at and beyond the notches, as seen at 35, to accommodate the wings 22 as best seen in FIGURE 6. At the junctions of these wings with the plate 21 are preferably formed shallow grooves 36 in alignment with the longitudinal centers of the notches 26 to assist in guiding the conductors, to be held by the grippers, and to give them a somewhat greater Contact area with the terminal plates as well as to prevent them from rolling laterally. Such conductors are indicated in section at 37 in FIG- URE 6 and for the purpose of permitting them to be inserted longitudinally, as indicated in FIGURE 4, the upper edge of plate 21 and its appurtenances are exposed through the back of the wiring device.

The dual gripper for the conductors is best seen in FIGURE 3 where it is generally referred to by the reference character 40. It is a complex formation of resilient steel wire, such as piano wire, bent from one piece thereof into the structure illustrated at 4t) to provide a pair of grippers. Each gripper has a free end cooperating with the wall of terminal plate 20, just within one of the wings thereof, serving to grip a wire which is introduced through the open side of notch 26 so as to prevent it from being withdrawn in accordance with the illustration in FIG- URE 4.

For purposes of convenience, the wire component 40 may be looked on as two, parallel-positioned, wire grippers each composed of two arms 41 and 42 connected together by an elbow 43 and divergent as best indicated in FIGURE 2. The arm 41, referred to as the gripper arm, is straight from its junction with the elbow, and the arm 42 is straight for most of its length beyond the elbow and then has a short section 44 bent through an angle of about in order that its end may rest on the shelf 33, previously referred to, when it is parallel to the bottom wall 32 of the notch in which it is received. To integrate the two wire gripper springs just delined, the wire beyond the parts 44 is bent at right angles and integrated with a transverse connection portion 45.

This whole component is shaped and sized to be received with each wire gripper in one of the two notches 26 and with the connecting portion 45 in channel 28, prior to the introduction and securing of the terminal plate 20. It is positioned as illustrated in FIGURES 2, 4 and 5 by having the elbows 43 resting against the walls 30 near the upper edges of the notches and by having the cross connecting portion 45 rest on the shelf 33 which places it beneath the lower edge of plate 21 as seen in FIGURE 4, when the latter is finally positioned, which serves to hold the wire complex 4t) in the position illustrated in that figure with the ends 41 of the gripper arms 41 engaging against or substantially against the plate 21 at a distance below the level of the elbow, which reaches almost two the rear surface of the wiring device base.

This makes each wire 41 form an acute angle with the surface of the plate, which angle decreases in extent as the conductor wire 37 is forced between its end 41 and the groove in the conductor plate as seen in FIGURE 4. The action of forcing such wire in position is resisted by the engagement of the bend 43 in the gripper wire with the surface 30 causing the wire to iiex in the bend and strongly forcing the sharp end thereof against the conductor wire, which is of soft copper, at such an angle that it cannot be withdrawn. Any tendency to withdraw it and the gripper wire along with it is resisted by the plate 21 resting on the stretch 45 connecting the two sets of gripper wires. This stretch cannot move out from beneath the lower edge of the plate 21 since the barrier 29 is too close against the outer face of plate 21 to permit movement of this portion upwardly. To assist in maintaining the gripper ends 4l of the gripper wires in alignment with the introduced conductors as seen at 37 in FIG- URE 6, the walls of each of the notches 26 are spaced only suihciently far apart to loosely receive the wire of the gripper but to prevent it from having any substantial lateral movement. FIGURE 6 shows that the conductor 37 is also limited in its lateral movement by first the inner wall of the adjacent wing 22 on the plate 21 and by the wall 47 which is offset slightly inwardly from the inner wall of the notch 26. Thus, the conductor 37 is hemmed in on three sides by stationary walls, one having groove 36 therein, and engaged on the fourth side by the end 4l. of the gripper arm 41 in such a manner that no matter how hard the conductor may be pulled it is only gripped tighter.

In order that the wireman may Withdraw a conductor should he introduce one improperly or place the wrong one in gripping engagement, a recess 50 seen in FiG- URES 1 and 6, and perhaps best in FIGURE 5, extends into the material of the base and through the outer wall of notch 26 and permits the introduction of a tool, such as a screwdriver as seen at 51 in FGURE 5, to engage the upper side of portion 41 of the gripper and depress it as indicated by the arrow in FIGURE 5 whereby its end 4.5 is Withdrawn from its engagement with conductor 37 so that the latter can readily be withdrawn and the proper conductor substituted.

The arrangement just described makes a simple, low cost and very effective wire gripper requiring a minimum of parts and of assembly operation. The materials are cheap and simple to manufacture, and the amount of time saved by the wiremen is very considerable over that of using screw-type terminals.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. An automatic dual conductor wire gripper comprising an insulating base, dual, parallel, laterally spaced substantially V-shaped notches in said base terminating substantially at a surface thereof and having one leg of each V-shaped notch substantially normal to said surface, a transverse channel connecting said legs for substantially their full depth and extending laterally beyond them, a terminal plate secured in and nearly lling said channel having a Wing on each edge substantially at right angles to the plate and each directed generaly toward the other leg of each V, a conductor wire gripper comprising a pair of divergent arms of spring wire integrated by a bend of the order of and arranged one pair in each said notch with the free end of each outermost arm substantially engaging said plate adjacent one of said wings at a position deeper in its notch than the bend between the arms of the pair, a straight transverse integral portion of said spring wire connecting the inner ends of the other arms together, and extending in said channel beneath the lower edge of said terminal plate, whereby the dual spring wire gripper unit is maintained in position in the V-shaped notches and connecting channel.

2. The wire gripper of claim 1 in which said terminal plate is grooved adjacent each wing to guide the free ends of said outermost arms and also the inserted conductor wire.

3. The Wire gripper of claim 1 in which the wall of said transverse channel which faces said terminal plate is spaced therefrom less than the diameter of said spring wire and said terminal plate substantially holds the transverse integral portion of said gripper assembly against the bottom of said channel.

4. The wire gripper of claim l in which the said base laterally of and through one side wall of each V-notch is recessed close to the said transverse channel and to a depth below the position of the outermost arm of gripper wire therein whereby a tool may be inserted to depress said arm and release a wire gripped thereby.

5. The wire gripper of claim 4 in which the recessed side wall of each V-notch is the outermost one.

6. In a wiring device housing of insulating material containing at least one contact member and means for automatically gripping and connecting a pair of conductor wires to said contact comprising a terminal plate electrically connected to said contact and having parallel wings turned up from opposite edges thereof, one end of said plate and of the wings being exposed through a wall of said housing to slidably receive an end section of one of said conductor wires adjacent each wing, a narrow groove in said housing extending normal to said plate adjacent the inner wall of each wing, a conductor wire gripping means in each groove comprising two arms of spring wire having an integral connecting elbow and diverging therefrom at a small included angle, a transverse channel connecting said grooves and receiving said terminal plate, one of the arms of each gripping means being the gripping arm and having a free end substantially engaging said terminal plate adjacent a wing thereof and more remote from the said surface end of the plate than said elbow, the ends of the other arms of each gripping means being integrated by a transverse portion of wire located in the bottom of said transverse channel and beneath the lower edge of said terminal plate for retention in the channel thereby, a wall in each groove being References Cited in the tile of this patent UNITED STATES PATENTS 2,883,641 Despard Apr. 21, 1959 3,018,461 Smith Jan. 23, 1962 FOREIGN PATENTS 751,675 Great Britain July 4, 1956

Claims (1)

1. AN AUTOMATIC DUAL CONDUCTOR WIRE GRIPPER COMPRISING AN INSULATING BASE, DUAL, PARALLEL, LATERALLY SPACED SUBSTANTIALLY V-SHAPED NOTCHES IN SAID BASE TERMINATING SUBSTANTIALLY AT A SURFACE THEREOF AND HAVING ONE LEG OF EACH V-SHAPED NOTCH SUBSTANTIALLY NORMAL TO SAID SURFACE, A TRANSVERSE CHANNEL CONNECTING SAID LEGS FOR SUBSTANTIALLY THEIR FULL DEPTH AND EXTENDING LATERALLY BEYOND THEM, A TERMINAL PLATE SECURED IN AND NEARLY FILLING SAID CHANNEL HAVING A WING ON EACH EDGE SUBSTANTIALLY AT RIGHT ANGLES TO THE PLATE AND EACH DIRECTED GENERALY TOWARD THE OTHER LEG OF EACH V, A CONDUCTOR WIRE GRIPPER COMPRISING A PAIR OF DIVERGENT ARMS OF SPRING WIRE INTEGRATED BY A BEND OF THE ORDER OF 180* AND ARRANGED ONE PAIR IN EACH SAID NOTCH WITH THE FREE END OF EACH OUTERMOST ARM SUBSTANTIALLY ENGAGING SAID PLATE ADJACENT ONE OF SAID WINGS AT A POSITION DEEPER IN ITS NOTCH THAN THE BEND BETWEEN THE ARMS OF THE PAIR, A STRAIGHT TRANSVERSE INTEGRAL PORTION OF SAID SPRING WIRE CONNECTING THE INNER ENDS OF THE OTHER ARMS TOGETHER, AND EXTENDING IN SAID CHANNEL BENEATH THE LOWER EDGE OF SAID TERMINAL PLATE, WHEREBY THE DUAL SPRING WIRE GRIPPER UNIT IS MAINTAINED IN POSITION IN THE V-SHAPED NOTCHES AND CONNECTING CHANNEL.

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