US3700009A

US3700009A - Wire joining tool

Info

Publication number: US3700009A
Application number: US100660A
Authority: US
Inventors: Robert Holbrook Cushman
Original assignee: Western Electric Co Inc
Current assignee: AT&T Corp
Priority date: 1970-12-22
Filing date: 1970-12-22
Publication date: 1972-10-24
Anticipated expiration: 1989-10-24

Abstract

A hand held, motor driven, wire joining tool is disclosed which includes two wire gripping jaws adapted to twist wires gripped therein by counter-rotating with respect to each other and a heater for melting insulation from the wires as they are twisted.

Description

United States Patent Cushman WIRE JOINING TOOL [72] Inventor: Robert Holbrook l-luntingdon Valley, Pa.

[73] Assignee: Western Electric Company, Incorporated, New York, NY.

[22] Filed: Dec. 22, 1970 [21] App1.No.: 100,660

Cushman,

[52] US. Cl ..140/l11, 140/119 [51] Int. Cl. ..B2lf 15/04 [58] Field of Search ..140/1l8,l19,122,123,124,

[56] References Cited UNITED STATES PATENTS Suzuki ..l40/1 19 1 Oct. 24, 1972 Primary Examiner-Jnwell A. Larson Attorney-R. J. Guenther and Edwin B. Cave 5?] ABSTRACT A hand held, motor driven, wire joining tool is disclosed which includes two wire gripping jaws adapted to twist wires gripped therein by counter-rotating with respect to each other and a heater for melting insulation from the wires as they are twisted.

14 Claims, 3 Drawing Figures PATENTEDncr 24 I972 3 700.009

' sum 1 OF 3 Uv l ENYTOR R. H. CUSHMAN A TTORNEV WIRE JOINING TOOL BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to wire joining techniques and pertains in particular to applications in which the wires to be joined are covered by a layer of insulation.

2. Description of the Prior Art In the telephone industry, the function of connecting, disconnecting and reconnecting wires is a never ending process. Since all three operations occur in huge numbers, the smallest economies in any one can produce large cost savings.

I-Ieretofore, connections have typically been made in two steps; i.e., first insulation is stripped away and then the exposed wires are twisted to form a mechanical bond. By reducing the number of steps in the connecting process, workmen will find their task easier and'efficiency can thus be improved. In this manner, cost economies can readily be achieved.

Accordingly, one object of this invention is to simplify the process of joining wires together.

The connected wires are typically tool joined and, where the insulation is stripped'prior'to. joining, more than one tool is usually required. For example, a knife or other stripping tool is ordinarily used to removethe insulation and a twisting tool such as pliers or the like is used to intertwine the exposed wires. While separate stripping and twisting tools generally give satisfactory results, multiple tools increase inventory. Moreover, tool losses occur and the inconvenience inherent in the use of two tools can readily decrease operator efficiency. Such drawbacks, however, can be overcome if the functions performed by the separate tools are combined into a single multi-purpose tool.

Accordingly, another object of this invention is to combine the functions of insulation stripping and wire twisting in one tool.

Additionally, if the single tool can perform both functions simultaneously, the operator's task will be simpler and easier to perfomi.

Accordingly, another object of this invention is to achieve simultaneous insulation stripping and wire twisting in a single tool.

In order to make a firm connection, the union between the wires must be tight and strong. While wrapping the wires tightly usually gives good results, it is better if the wires can be bonded to each other as well.

Accordingly, another object of this invention is to achieve bonding of the wires during the twisting and insulation stripping operation.

SUMMARY OF THE INVENTION In accordance with this invention, two or more parallel insulated wires are stripped of their insulation while simultaneously being twisted together to form either a mechanical bond or a true fusion or thermal compression bond.

According to one feature of this invention, simultaneous insulation stripping and wire twisting is achieved by applying heat to the wires as they are twisted so that melted insulation is squeezed from between the wires to expose bare metal.

According to another feature of this invention, a wire joining tool for stripping insulation from wires and twisting the wires to form a connection comprises two jaws for twisting asegment of wires gripped therein, a support'holding' the two jaws, and a'heater for applying 'heat to the segment gripped in the two jaws.

According to another feature of this invention the heater applies heat to the insulation of the wires as they are being twisted by the jaws'whereby the insulationwhich portions are broken away to show details;

FIG. 2 is a partial plan view of the wire joining tool shown in FIG. 1 and has portions broken away to show details; and

FIG. 3 is an elevation view of the wire joining tool shown in FIG. 2 taken along the lines 3--3 and has portions broken away to show details and includes an alternate heating arrangement.

DETAILED DESCRIPTION Referring to FIG. 1, a wire joining tool is disclosed which comprises a shaft 10, a collar 11, a handle 12, jaws 13, jaws 15, a sleeve 14 and a linkage 17. The illus- "trated tool is a hand-held device in which all of the foregoing components cooperate to simultaneously strip insulation from and twist two or more wires into a electrical and mechanical connection.

The shaft 10 is cylindrical and, as best seen in FIG. 3, one end includes a hole which is tapped to accommodate a threaded member. The other end is attached to a motor (not shown) which may conveniently be mountedon-the handle 12 and which is adapted to impart rotational motion to the shaft 10 when actuated. The shaft 10 is advantageously made of stainless steel alloy and, asbest seen in FIGS. 1 and 3, includes a groove to accommodate one or more conductor leads 16. While not explicitly shown, one of the conduction leads 16 is connected at one end to a current source (not shown) through a switch 18 in the handle 12 in a conventional manner and has its other end connected to the jaws 13. Similarly, another conductor lead 16 extends from the jaws 13 to the other end of the current source to complete an electrical circuit.

The collar 11 comprises a face block 20 having a hole of sufficiently large diameter to slidably accommodate the shaft 10. In addition, it includes two projecting ears 21 and four projecting pins 22. As shown in FIGS. 1 and 3, the ears 21 cooperate with moving parts in the handle 12. Advantageously, the face block 20 is made of a material such as stainless steel.

The handle 12 comprises the aforementioned switch 18, a grip 24 and a trigger 25 mounted on a pivot 28. The grip 24 is conveniently made of an electrically nonconducting material such as phenolic, and the switch 18 and the pivot 28 are advantageously mounted therein. As best seen in FIG. 2, two ears 26 project from the end of the trigger 25 and are coupled to the ears 21 on the collar 11 by connecting pins 27 so that the face block 20 will slidably reciprocate on the shaft in response to rotation of the trigger 25 about the pivot 28.

As best shown in FIG. 3, the switch 18 is activated in response to rotational movement of the trigger 25. When actuated, it closes an electrical circuit (not shown) so that current will flow through the two leads 16 which are electrically connected to the jaws in a conventional manner.

As illustrated best in FIG. 3, the jaws 13 comprise two elongated legs 30 separated by an end support 31. As shown in FIG. 3, the end support 31 is threaded so as to screw into the tapped hole in the end of the shaft 10. Consequently, when the end support 31 is screwed into the hole, the jaws 13 will rotate when the shaft 10 rotates.

The legs 30 are adapted to flex at the point of juncture with the end support 31 and are made of a material such as inconel 718. The outer side of each leg 30 includes a cam surface 32 which, when subjected to a compression force, will urge the two legs 30 toward one another so as to grip a wire or wires inserted therebetween. As shown in FIG. 3, each conductor lead 16 is attached to one of the two legs 30 so that current flowing therethrough will cause the jaws 13 to be heated.

- The sleeve 14, as can be seen from FIG. 3, is hollow along its long axis so as to slidably accommodate the shaft 10. It has a shoulder 38 at one end and two cam surfaces 36 at the other end. The cam surfaces 36 are adapted to engage the cam surfaces 32 on the jaws 13 and to compress the jaws 13 in response to pressure exerted by the sliding movement of the collar 11. The sleeve 14 may advantageously be made of a material such as stainless steel.

The sleeve 14 also includes a slot 37 adapted to accommodate a pin 39. As shown in FIG. 3, the pin 39 is inserted in the side of the shaft 10 so as to limit the sliding movement of the sleeve 14 thereon.

As best seen from FIGS. 2 and 3, the jaws 15 include two facing clamping plates 40. Each clamping plate 40 advantageously contains groove 41 for accommodating two or move wires during the clamping process and extends tranversely between the ends of the two arms 45. For convenience, the clamping plates 40 can be made of stainless steel to retard heat conduction.

As illustrated in FIGS. 1 and 2, the arms 45 are part of a linkage 7 and may be made of stainless steel. Each arm 45 includes a slot 47 at one end. Moreover, each is attached to a clamping plate 40 at the other end and is joined to an adjacent arm 45 by a centrally located pivot pin 46. Both pivot pins 46 are held stationary with respect to the shaft 10 by a pair of brackets 48 which, as best seen in FIG. 2, are rigidly fastened to the grip 24 but which are advantageously electrically insulated from the grip 24 by use of insulation such as washers or spacers made out of polyimide or equivalent insulating material. As a result, the jaws 15 are unable to rotate as are the jaws 13. The slots 47, as best seen in FIGS. 1 and 2, are filled by the pins 22 which rotate the arms 45 about the pivot pins 46 in response to the reciprocal movement of the face block as it slides on the shaft 10 and thereby cause the jaws 15 to open and close.

The jaws 15 may include, if desired, two insulation collecting cups 50. As shown in FIGS. 2 and 3, the two cups 50 cooperate with each other to accumulate insulation melted from wires being twisted together by the

jaws

13 and 15.

In operation, two or more wires are inserted, as shown in FIG. 1, through the jaws 15 in parallel with each other and into the jaws 13. Thereafter, the trigger 25 is actuated to slide the collar 1 1 forward on the shaft 10. As the collar 1 1 slides, it simultaneously rotates the arms 45 and pushes the sleeve 14 forward. The rotational movement of the arms 45 closes the jaws 15 against the wires at one point and the sliding movement of the sleeve 14 presses the cam surfaces 36 against the cam surfaces 32 and thereby closes the jaws 13 against the wires at another point.

As the trigger 25 continues to move, it actuates the switch 18 to simultaneously energize the motor (not shown) and close a circuit leading from a low voltage, high current source such as a stepdown transformer, for example (not shown). The leads 16 are connected to the low voltage source so that current will pass serially through the jaws 13 when the circuit is closed.

With the circuit closed, current will continue to flow until the jaws l3 become heated and the insulation on the wires begins to soften and even melt. If desired, heating is continued until the metal in the wires reaches wire bonding temperature. As the insulation softens and melts, it is squeezed out between the twisted wires and is trapped in the cups 50 where it is retained until the twisting operation is complete.

As the insulation is softening or melting, the motor (not shown), is rotating the shaft 10. As a consequence, the jaws 13 are also rotating and the segment of wires located between the

jaws

13 and 15 is being twisted.

Twisting creates a tensile stress on the segment of the wires between jaws l3 and 15 which continues until breakage occurs. As heat is applied to the wires from the jaws 13, the portion nearest the jaws 13 becomes hottest. Consequently, that portion will be the weakest point structurally in the segment. As a result, when the wires break, the rupture will occur just beyond the tips of the jaws 13. The resulting connection, therefore, will ordinarily have a neat, clean appearance. Moreover, the magnitude of force which must be reached in order to obtain rupture will automatically cause the heated, unbroken wires in the segment to be joined by a fusion or compression type bond.

The connection or union between the wires is completed by releasing the trigger 25. When the trigger 25 is released, the

jaws

13 and 15 open and allow the connected wires to be withdrawn. If the jaws 15 include cups 50, the joined wires will be pulled through melted insulation as they are withdrawn. As a result, the melted insulation will be rewiped back onto the exposed surfaces of the wires thereby producing a joint which not only has good mechanical and electrical properties, but which will also be covered with insulation. Advantageously, the motor can be made to rotate against a spring load in a conventional manner when it is energized. As a result, a number of turns made by the jaws 13 can readily be controlled, for example, full twisting of the wire segment can readily be made to coincide with full rotation of the jaws 13. In such a case, the spring loading can readily be used to untwist the jaws 13 and return them to the initial position. Where this arrangement is used, the leads 16 need only be long enough to continue wrapping until the jaws 13 have fully rotated.

While electric heating is particularly convenient, other forms of heating can also be utilized. It is essential only that the temperature of the segment of the wires be raised to a level sufficient to melt the insulation so that a good metal-to-metal contact can be achieved. Where electric heating is used, temperature is readily controlled merely by adjusting the amount of current applied. It has been discovered that adjusting the temperature to a level in the range of 500 to l500 Fahrenheit will produce bonds of good quality.

As an alternate, a cartridge heater 60 can be used as the mechanism for supplying heat to the jaws l3 and the wire segment gripped therein. As shown in FIG. 3, the sleeve 14 has a shoulder at one end over which the hollow cartridge heater 60 can slide. When the cartridge heater 60 is used, the leads 16 are connected to the cartridge leads instead of the the jaws 13. In either case, however, heat can be supplied in response to pulses or a continuous flow of current.

In summary, a single tool for joining two or more wires by simultaneously twisting and heating the portions to be connected has been disclosed. It will be understood, however, that the embodiment disclosed herein merely embodies the principles of the invention and that other embodiments falling within the scope of the invention will readily occur to those skilled in the art.

What is claimed is: l. A wire joining device for uniting the free ends of two or more insulated wires comprising:

a pair of jaw means for gripping the opposite ends of a segment of said wires;

means for rotating one of said jaw means with respect to the other so as to twist said segment; and

heater means for melting insulation from wires in said segment when said segment is being twisted by said jaw means whereby said wires will be simultaneously stripped of insulation and twisted into a mechanical connection, said heater means including a source of electric current, conductor means for connecting said pair of jaw means to said source of electrical current and means for interruptably allowing current to flow serially through one of said jaw means, a segment of wires gripped in said one jaw means and the other of said jaw means when said jaw means are twisting said segment of wires.

2. A wire joining tool for uniting the free ends of two or more insulated wires comprising:

a rotatable sh aft;

means for rotating said shaft;

a collar slidably mounted on said shaft;

handle means for sliding said collar back and forth on said shaft;

first jaw means for holding said wires together in parallel at one point, said first jaw means being rigidly attached to said shaft so as to rotate when said shaft rotates;

sleeve means for opening and closing said first jaw means in response to reciprocal movement of said collar on said shaft, said sleeve means being slidably mounted on said shaft;

second jaw means for holding said wires together in parallel at another point;

means for removing insulation from wires gripped in said first and second jaw means when said shaft is rotated; and

linkage means for opening and closing said second jaw means in response to reciprocal movement of said collar on said shaft and for holding said second jaw means fixed with respect to rotational movement of said shaft whereby wires gripped by said first and second jaw means will be simultaneously stripped of insulation and twisted when said shaft is rotated.

3. A wire joining tool in accordance with claim 2 wherein said first and second jaws are electrically insulated from each other, and said means for removing insulation is a heater for melting insulation on said wires.

4. A wire joining tool in accordance with claim 3 wherein said heater includes means for applying an electrical current serially through said first jaw means, wires gripped in said first and second jaw means and said second jaw means when said wires are being twisted.

5. A wire joining tool in accordance with claim 2 wherein said first jaw means includes two elongated jaws and first cam surfaces on each of said jaws for closing said jaws when subjected to a compressive force, and said sleeve means includes second cam surfaces for applying a compressive force to said first cam surfaces in response to sliding movement of said collar on said shaft.

6. A wire joining tool in accordance with claim 5 wherein said two elongated jaws have a common threaded end support and said shaft includes a tapped hole for accommodating said threaded end support.

7. A wire joining tool in accordance with claim 2 wherein said linkage means includes a pair of arms centrally joined to each other by a pivot pin and camming pins for imparting reciprocal rotation to said arms around said pivot pin in response to reciprocal sliding movement of said collar on said shaft, and said second jaw means includes two opposed jaws attached to said arms and arranged to grip and release wires inserted therebetween in response to reciprocal rotation of said arms about said pivot pin.

8. A wire joining device in accordance with claim 7 wherein said second jaw means includes spreading means for coating said wires with melted insulation as said wired are removed from said two opposed jaws.

9. In a wire joining method for uniting two or more parallel insulated wires in which the wires are initially held in fixed relationship to each other at two separate points, the step of applying heat to segments of said wires lying between said points while simultaneously twisting said segments together whereby heated insulation is squeezed from between adjacent twisted wires and a metal-to-metal bond is formed having great mechanical strength and good electrical conductivity.

10. A wire joining method in accordance with claim 9 wherein said heat is applied until said insulation melts sufficiently to expose bare metal on adjacent surfaces of said wires whereby extensive metal-to-metal contact is established between adjacent wires.

11. In a wire joining method in accordance with claim 10, the additional step of spreading melted insulation back over the exposed bare metal of said wires after said bond is formed to reinsulate said wires.

12. A wire joining method in accordance with claim 9 wherein said heat is applied until said wires reach bonding temperature whereby the wires readily deform cross-sectionally during twisting and a good electrical union is formed between adjacent wires.

13. A wire joining method in accordance with claim 12 wherein twisting is continued until the wires rupture.

14. A wire joining method in accordance with claim 12 wherein heat applied to said wires falls in the range of 500 to 1,500 Fahrenheit.

Claims

1. A wire joining device for uniting the free ends of two or more insulated wires comprising: a pair of jaw means for gripping the opposite ends of a segment of said wires; means for rotating one of said jaw means with respect to the other so as to twist said segment; and heater means for melting insulation from wires in said segment when said segment is being twisted by said jaw means whereby said wires will be simultaneously stripped of insulation and twisted into a mechanical connection, said heater means including a source of electric current, conductor means for connecting said pair of jaw means to said source of electrical current and means for interruptably allowing current to flow serially through one of said jaw means, a segment of wires gripped in said one jaw means and the other of said jaw means when said jaw means are twisting said segment of wires.

2. A wire joining tool for uniting the free ends of two or more insulated wires comprising: a rotatable shaft; means for rotating said shaft; a collar slidably mounted on said shaft; handle means for sliding said collar back and forth on said shaft; first jaw means for holding said wires together in parallel at one point, said first jaw means being rigidly attached to said shaft so as to rotate when said shaft rotates; sleeve means for opening and closing said first jaw means in response to reciprocal movement of said collar on said shaft, said sleeve means being slidably mounted on said shaft; second jaw means for holding said wires together in parallel at another point; means for removing insulation from wires gripped in said first and second jaw means when said shaft is rotated; and linkage means for opening and closing said second jaw means in response to reciprocal movement of said collar on said shaft and for holding said second jaw means fixed with respect to rotational movement of said shaft whereby wires gripped by said first and second jaw means will be simultaneously stripped of insulation and twisted when said shaft is rotated.

14. A wire joining method in accordance with claim 12 wherein heat applied to said wires falls in the range of 500* to 1,500* Fahrenheit.