US3707041A - Shield termination apparatus - Google Patents

Abstract

An apparatus for terminating a portion of an external woven shield of a shielded wire to be removed without damaging the insulation covering a center conductor of the shielded wire.

Description

United States Patent Ramsey [451 Dec. 26, 1972 [541 SHIELD TERMINATION APPARATUS [72] Inventor: Raymond Ramsey, Mishawaka,

Ind.

[73] Assignee: The Bendix Corporation [22] Filed: March 18, 1971 [21] Appl. No.2 125,664

7 [52] US. Cl ..30/9l.2, 225/96 [51] Int. Cl. ..II02g l/l2 [58] Field of Search ...30/90.l, 91.2; 8l/9.5 R, 9.5 B, 81/9.5 C, 9.51; 225/96, 96.5

[56] References Cited UNITED STATES PATENTS 1,305,513 6/1919 Bernard ..81/9.5 R

2,054,973 9/1936 Ferguson... 3,103,572 9/1963 Ewald ..81/9.5l 3,339,437 9/1967 Hamilton et a1 ..8 l/9.51 3,599,514 8/1971 Fornkahl ..8I/9.5 R

FOREIGN PATENTS OR APPLICATIONS 127,119 3/1948 Australia ..30/91.2

Primary Examiner-Robert C. Riordon Attorney-William N. Antonis and Flame, I-lartz, Smith & Thompson [57] ABSTRACT An apparatus for terminating a portion of an external woven shield of a shielded wire to be removed without damaging the insulation covering a center conductor of the shielded wire.

6 Claims, 6 Drawing Figures PATENTED HEB 2 6 I972 IVENTOR. PA YMO/VD (I AMA/I515 Y A T TORNEY SHIELD TERMINATION APPARATUS BACKGROUND OF THE INVENTION In electrical devices requiring many operational electrical energy signals, a cable assembly made up of connectors and wires carries information from various sources supplying information to the functioning components. This information transmitted from the outside sources could contain several energy frequencies, both high and low. To prevent these signals from creating an interaction with each other by induction, a woven shielded jacket is placed around the transmission wires. Each of the shielded wires is usually made up of a center of twisted strand conductors covered by an insulation material. Over this insulation is woven many smaller wires creating an outside jacket or shield. When an informational signal is transmitted through the center conductor, with the outside shield or jacket grounded, the magnetic effect created by electrical energy flow is contained within the wire. Conversely, any signal generated by an outside source will not affect the frequency of the signal carried by the center conductor.

ln assembly of the shielded wire into the cable or to the electrical device, it is necessary to ground the woven shield while at the same time be assured that each strand is terminated in substantially the same location, in such a manner as to prevent both a low and high resistance short between the center conductor and the grounded shield.

Many methods have been used to reduce the possibility of the grounded shield from contacting and shorting the conductor wire including:

(a) securing a metal ferrule to the shield and attaching the ferrule to an outside ground; (b) feeding the insulated center conductor through an opening in the shield in such a manner as to prevent a short between shield and center conductor; (c) removing a portion of the woven shield by an electrical arc, etc. However, a preferred method by many operators would be to tin the shield in the area where termination is desired with solder, using a standard soldering iron for making sure the solder flows around the entire circumference of the woven shield and then with a sharp blade making a cut by rolling the wire on the edge of the blade by hand. The blade which cuts into the shield makes a partial penetration but does not cut through the insulation. The wire is then flexed back and forth until the shield completely breaks, after which the unwanted portion is removed. Unfortunately, in the cutting operation, the partial penetration, which is controlled solely by the feel of the operator, could cause a slight damage to the insulation directly over the center conductor. A break or even reduction in the surface covering area of the insulation due to a severe indentation could cause a short between the shield and the center conductor at some later date. Moreover, the shield must be terminated in a manner such that no barbs or sharp projections could penetrate the insulation causing a short due to movement or pressure exerted from the outside.

Other devices used as an aid in shield termination'include: parallel razor blades, diagonal pliers, mtiltiholed hand strippers, and a hand held clamping prong with a central opening which rips the covering from the carrier. However, all the above devices for the removal of the shield material from around an insulated center conductor carrier depends entirely upon the skill of the operator in gaging the depth of the cut, the size of the hole to use in stripping and the force needed to be applied to score the covering. Unfortunately, no two terminations will be exactly the same. As a result, in quality production where installation of insulated shielded wire is critical, the rejection rate in using the above type termination devices is extremely high.

SUMMARY OF THE INVENTION I have devised a shield termination tool, which will clamp on a shielded wire and crimp a ring around a tinned portion of the shield, for providing an accurate point for termination of a shield repeatedly in the exact same manner.

To accomplish this, a first holding member is placed on a movable body. The first holding member has a center opening with an accurate groove contained therein conforming to the size of the outer diameter of the wire. A first blade with an accurate cutting edge is held onto the movable member by a pair of aligning pins. A second member held on a second movable body has a second blade held thereon having a projection with an accurate cutting edge. The first and second blades are brought together, through a series of aligning members, where the cutting edges mate to provide a circular crimped ring around a tinned section of the woven shielding member. Upon flexing the cable while holding the tool secure, the tinned shield will snap at the point of the desired termination. The termination tool is now removed and the severed shield portion removed from the wire. Through this termination tool the same type termination will be provided with each application.

It is the object of this invention to provide the means whereby an external woven grounded shield of a wire can be terminated without damaging the insulation covering a center conductor.

It is another object of this invention to provide a shield termination device which will repeatedly give the exact type of end termination on a jacket covering an insulator conductor.

It is another object of the invention to provide means whereby new cutting blades of a shield termination apparatus can be changed to maintain a sharp cutting edge for engaging a shield.

It is still a further object of this invention to provide an accurately controlled hand held shield termination device with spacer members which will align and guide a cutting blade which precisely crimp an annular ring around a shield of an insulated energy carrier at a desired point of termination.

These and other objects of my invention will become readily apparent for those who view the drawings and specification.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing the woven ground shield termination apparatus holding a piece of shielded wire; I

FIG. 2 is a perspective view showing the shield termination apparatus of FIG. 1 in the open position;

FIG. 3 is a side view of the termination apparatus of FIG. 1;

FIG. 4 is a view taken along line 44 of FIG. 3;

FIG. 5 is a sectional view taken along line 55 of FIG. 4;

FIG. 6 is a perspective view showing a segment of the grounded shielded cable removed from the insulation of the transmission cable.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The shield termination apparatus 10 as shown in FIGS. 1, 2, 3 and 4 consists of a first body member 12 attached to a first jaw member 14 having axial pins 16 and 18 extending from the body member 12. A spacer member 22 is slipped onto the aligning pins 16 and 18. The spacer member 22 has a central opening 24 with an axial groove 26 substantially parallel to the aligning pins 16 and 18. Along the top of the central opening 24 a perpendicular slot 28 is located. A first blade member 30 is placed adjacent the spacer member 22 on the aligning pins 16 and 18 and a set screw 25 firmly attaches the first blade member 30 to the first body member 12, as shown in FIG. 5. The blade member 30 has a central opening 32 with a semi-circular cutting edge 34 in a plane normal to the axial groove 26 in the first spacer member 22. A second body'member 36 is secured to a second jaw member 38. The second body member 36 has a pair of aligning pins 40 and 42 which are substantially parallel and axially aligned with the aligning pins 16 and 18 of the first body member 12. A second spacer member 44 placed on the aligning pins 40 and 42 has a central projection 46. The central projection 46 has an axial groove 48 substantially parallel to groove 26 of the first spacer member 22. A key member 50 located perpendicularly with the central projection 46 extends to the outer limits of the second spacer member 44. A second blade member 52 is placed on aligning pins 40 and 42 adjacent the second spacer member 44 and held tight against the second body by set screw 53, as shown in FIG. 5. The second blade member 52 has a central projection 54 with a semi-circular cutting edge 56 in a plane normal to the axial groove 48 in the second spacer member 44. A first handle 58 attached to the first body member 12 has a U-shaped member with legs 59 and 61. A first pivot pin 62 extends through legs 59 and 61 of the U-shaped member to hold the second jaw member 38 in alignment with the first jaw member 14..A second handle 60 is secured to the second body member 38 by a second pivot pin 64. An over the center lever arm 68 has a first end 71 which surrounds leverage pin 70 attached to the second handle 60 and a second end 73 retained in the first handle against an adjustable means 72. A curved portion 69 of the lever arm 68 adjacent end 71 mates with end 65 of a quick release member 66. The adjustable means 72 will move end 71 in the first handle to change the location of leverage pin 70 with respect to v the first pivot pin 62. Upon applying a compressive input force to move the first and second handles together, end 73 will pivot on the end of the adjustable means 72 allowing the input force to be communicated through thesecond handle between the leverage pin 70 and the second pivot pin 64. The input force transmitted to the second pivot pin 64 causes jaw member 38 to pivot on pin 62 and thereby move the first and second body members together through the use of a well known toggle connection as described in US. Pat. Nos. 2,280,005 and 2,514,150. When jaw member 38 has rotated to a position where leverage pin 70 is in a straight line with end 73 and the second pivot pin 64, with any further movement of the leverage pin 70 toward the first handle 58, an over the center or toggle lock is achieved. In the over the center or toggle lock position, the shielded wire 2 will be fixedly retained between grooves 26 and 48.

The over thecenter or toggle lock is released by applying a compressive force between the end 61 of the second handle and end 67 of the quick release means 66. This compressive force will rotate the quick release means 66 about pin 59 causing end to engage the curved portions 69 to move leverage pin 70 in a direction away from the first handle 58 past a straight line between the second pivot pin 64 and end 73. As the leverage pin 70 moves past this straight line, a spring member 74 will aid in moving the first and second body members 12 and 36, respectively, away from each other by pulling on the second jaw member 38 to the position shown in FIG. 2.

MODE OF OPERATION OF THE PREFERRED EMBODIMENT I A shielded wire 2 is tinned at a desired point of termination to fill the voids between the strands to make a solid portion 7 on the woven shield member '8, as shown in FIG. 6. This tinned portion 7 is placed in groove 26 of the first body member 12 and groove 34 g of the first blade member 30, as shown in FIG. 1. The first and second jaw or body members 14 and'38 are moved toward each other by an operator compressing the first and second handles 58 and 60 until the key member 50 engages in. the slot 28 and the central projection'46 mates with the central opening 24. With further movement the semi-circular cutting edges 34 and 56 contained in the first and second blades 30 and 52 contact the tinned portion 7 of the conduit 2. Upon still further compressing of the handles 58 and 60, jaw member 38 will rotate on the first pivot pin 62 until the lever pin 70 attached to the lever arm 68 has moved into an over the center or toggle lock position simultaneously with the key member 50 contacting the bottom of slot 28 and central projection 46 contacting the bottom of the central opening 24- causing the blade members 30 and 52 to score. an annular ring on the tinned portion 7 of shielded wire 2 to a depth immediately above the insulation 4, as shown in FIG. 5.

Because of the position of the pin 70 with respect to an imaginary straight line running from the end 73 of the lever arm 68 and the second pivot pin 64, the blades 30 and 52 will be locked in the closed position until manually released by compressing member 66 which shifts the position of the leverage pin 70 through which the force is applied. While still in the closed position, the shield termination apparatus 10 is held stationary and the shielded wire is moved back and forth.

then removed and a heating instrument (not shown) is then placed onto the severed portion of the shielded wire allowing the solder to flow so that the unwanted portion of the shield can be removed from around the insulated wire. The resulting termination of the woven shield member 8 will be a clean break without any ragged or frayed strand ends as shown in FIG. 6. The solder on the end of the woven shield member 8 will hold the strands as a single piece eliminating the possibility of frayed ends working their way into the insulation 6 and shorting the shield to the center conductor.

. As shown in FIG. 5 the semi-circular cutting edges 34 and 56 in the blade members 30 and 52 lie in a plane normal to the grooves in the space members 22 and 42. These blade members 30 and 52 can be easily interchanged after a predetermined number of applications to provide a sharp edge on the bevelled portion. The sharp edge will assure that the tinned shield will be terminated clearly without any frayed strands from the woven shield 8.

While a hand held manner is shown in the embodiment connected to the first and second body means as the force for moving the first and second members toward each other, it is envisioned that in an assembly line the members could be moved toward each other by a hydraulic press since the depth of penetration of the first and second blades is completely controlled by the key-slot and projection opening members mating and stopping the movement at a point without damaging the insulation of the conduit.

Thus, I have provided an apparatus and a method of removing the woven metallic ground shield from a shielded wire with the use of a controlled blade. Through my invention the time consuming task of checking for frayed ends of a woven ground shield will be substantially eliminated with an improved insulation resulting.

I claim:

1. An apparatus for scoring a tinned portion of an external woven shield of a shielded wire having an inner insulated transmission line, said apparatus comprising:

a first body attached to a first member having a first axial aligning pin;

a second body attached to a second member having a first axial aligning pin;

a first spacer member carried by the first aligning pin of said first body having a central opening with an axial groove, said first spacer member having a slot perpendicularly located relative to said central opening and extending to the limits of said second spacer member;

a second spacer member carried by said first aligning pin of said second body having a central projection with an axial groove, said second spacer member having a key perpendicularly located relative to said central projection and extending to the limits of the first spacer member; I

first blade means located on the first aligning pin of said first body'adjacent said first spacer member having a central opening with a semi-circular cutting edge in a plane normal to said axial groove in said first spacer member, said second semi-circular groove retaining said tinned portion of said woven shield;

second blade means located on said first aligning pin of said second spacer member having a central projection with a first semi-circular cutting edge in a plane normal to said axial groove in said second spacer member; and

compressing means operatively connected to said first and second members for moving said first and second spacer members into controlled engagement whereby said key and slot and said central projection and opening mate to align said first and second semicircular cutting edges to assure an annular ring being formed in the tinned portion of said woven shield by said first and second blade means without damage to the insulated transmission line.

2. The apparatus, as recited in claim 1, wherein said first body includes:

a second axial aligning pin parallel to said first axial aligning pin to provide stability and support to said first blade means upon engagement with said second blade means.

3. The apparatus, as recited in claim 2, wherein said second body includes:

a second axial aligning pin parallel to said first axial aligning pin to provide stability and support to said second blade means upon engagement with said first blade means.

4. The apparatus, as recited in claim 3, including:

means for securing said first blade means to said first body to hold the first spacer member tight against said first body.

5. The apparatus, as recited in claim 4, including:

means for securing said second blade means to said second body to hold the second spacer member tight against said second body.

6. The apparatus, as recited in claim 5, wherein the first and second blade means are removable to permit the semi-circular cutting edges to be replaced after a predetermined period of use to assure a sharp and distinct ring is produced on said tinned portion of the shield wire.

Claims (6)

1. An apparatus for scoring a tinned portion of an external woven shield of a shielded wire having an inner insulated transmission line, said apparatus comprising: a first body attached to a first member having a first axial aligning pin; a second body attached to a second member having a first axial aligning pin; a first spacer member carried by the first aligning pin of said first body having a central opening with an axial groove, said first spacer member having a slot perpendicularly located relative to said central opening and extending to the limIts of said second spacer member; a second spacer member carried by said first aligning pin of said second body having a central projection with an axial groove, said second spacer member having a key perpendicularly located relative to said central projection and extending to the limits of the first spacer member; first blade means located on the first aligning pin of said first body adjacent said first spacer member having a central opening with a semi-circular cutting edge in a plane normal to said axial groove in said first spacer member, said second semi-circular groove retaining said tinned portion of said woven shield; second blade means located on said first aligning pin of said second spacer member having a central projection with a first semi-circular cutting edge in a plane normal to said axial groove in said second spacer member; and compressing means operatively connected to said first and second members for moving said first and second spacer members into controlled engagement whereby said key and slot and said central projection and opening mate to align said first and second semicircular cutting edges to assure an annular ring being formed in the tinned portion of said woven shield by said first and second blade means without damage to the insulated transmission line.

2. The apparatus, as recited in claim 1, wherein said first body includes: a second axial aligning pin parallel to said first axial aligning pin to provide stability and support to said first blade means upon engagement with said second blade means.

3. The apparatus, as recited in claim 2, wherein said second body includes: a second axial aligning pin parallel to said first axial aligning pin to provide stability and support to said second blade means upon engagement with said first blade means.

4. The apparatus, as recited in claim 3, including: means for securing said first blade means to said first body to hold the first spacer member tight against said first body.

5. The apparatus, as recited in claim 4, including: means for securing said second blade means to said second body to hold the second spacer member tight against said second body.

6. The apparatus, as recited in claim 5, wherein the first and second blade means are removable to permit the semi-circular cutting edges to be replaced after a predetermined period of use to assure a sharp and distinct ring is produced on said tinned portion of the shield wire.

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