Impact tool

Abstract

An impact tool for such applications as terminating wire in bifurcated terminals comprises an impact mechanism having a hammer substantially enclosed within a power spring. The return spring is located in a passage within the hammer and the impact surface of the hammer is about the internal passage. Thus a large mass hammer and springs which provide substantial impact forces and energy can be utilized without requiring an excessive overall size of length for the mechanism. A variety of heads can be powered by the mechanism for seating and trimming a plurality of conductors simultaneously and for seating multipair connector blocks.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a tool for seating and trimming wires and mounting connector blocks on bifurcated electrical terminals.

2. Description of the Prior Art

Connectors having bifurcated or split terminals into which conductors are inserted for termination are widely used in the telephone systems. One such connector which is finding increasing usage is known as an "88-type" connector and is described in U.S. Pat. Nos. 3,611,264 and 3,631,378 issued to B. C. Ellis, Jr. on Oct. 5, 1971 and Dec. 28, 1971, respectively, and assigned to applicant's assignee. This 88-type connector includes an index strip in which wires are seated and then trimmed. Multipair connector blocks such as five-pair blocks are then mounted over the index strip to establish connection with the wires therein. The blocks then provide terminals on their opposite edge to which cross-connect wires can be terminated.

In order to reduce installation time it is required that multiple wire pairs, e.g., five pairs, simultaneously be seated in the index strip and trimmed if desired. However, the forces and energy required for such simultaneous operations on multiple wire pairs and the forces and energy required for mounting connector blocks on the index strip are higher than those which can be reasonably applied by a craftsperson over an extended period with the brute force manual tools presently available. While presently known impact termination tools such as shown in U.S. Pat. No. 3,708,852 issued to J. R. Mason on Jan. 9, 1973 do eliminate the brute force requirement of prior tools, they are designed for single terminal operation and accordingly do not provide anywhere near the energy and force levels required for the simultaneous seating and trimming operations on the connector block mounting operation previously discussed. A mere scaling up of these known impact termination tools to provide the high energy and force levels required would result in a tool much too long and large to be practical. Further, these prior tools are designed for a different type connector, i.e., a "66-type" connector, and are thus not directly compatible with the newer 88-type connector.

Accordingly it is an object of this invention to improve impact termination tools to provide higher energy and force levels.

Another object is to provide an impact termination tool which can perform operations on a multiplicity of conductor pairs simultaneously.

Still another object is to provide a tool which can seat and trim a plurality of wires and mount connector blocks on bifurcated terminals.

SUMMARY OF THE INVENTION

The foregoing objects and others are achieved in accordance with this invention by a termination tool comprising a handle having a plunger extending therefrom to which a head is fastened for seating and trimming a plurality of wires in bifurcated terminals or for mounting connector blocks. An impact mechanism within the handle impacts the plunger to provide the required high force and energy levels for the seating, trimming and mounting operations. The impact mechanism comprises a high mass hammer having an axial passageway therethrough for receiving the plunger. A conical tapered impact shoulder around this passageway is adapted for impacting with a conical flange on the plunger. A power spring surrounds substantially the entire length of the hammer to provide a high acceleration force thereto upon triggering to thereby cause the hammer to impact the plunger with high forces. A return spring surrounds the plunger within the passageway to return the mechanism to its initial configuration after the impact.

BRIEF DESCRIPTION OF THE DRAWING

The invention will be more fully comprehended from the following detailed description and accompanying drawing in which:

FIG. 1 is a longitudinal sectional view of the termination tool of this invention;

FIG. 2 is a perspective view of a portion of one type of head for use with the tool of FIG. 1 for simultaneously seating a plurality of wire pairs, and for mounting connector blocks; and

FIG. 3 is a perspective view of a portion of a second type of head for simultaneously seating and trimming a plurality of wire pairs.

DETAILED DESCRIPTION

As shown in FIG. 1, the tool 101 of this invention comprises a hollow cylindrical housing 2 having threaded ends 4 and 6 into which threaded end caps or covers 8 and 10, respectively, can be screwed. Cap 8 has a pin 12 extending therefrom for reasons to be discussed subsequently. Cap 10 has an axial opening 14 therethrough for slidably receiving a plunger or rod 16 therein so that one end 18 of the plunger 16 extends from housing 2 while the other end 19 extends upward in housing 2. The end 18 of plunger 16 can be threaded or otherwise adapted to have mounted thereon a head 20 which contacts the wires and connector blocks to perform the seating, trimming and mounting operations thereon as will be discussed subsequently.

Plunger 16 includes a flange or shoulder 22 thereabout which limits the outward movement of plunger 16 by contacting cap 10. One side 24 of flange 22 provides an impact surface or anvil for imparting an impact force to plunger 16. This side 24 is conically tapered so that flange 22 can only deform in compression from an impact force on surface 24 thereby eliminating the cantilevered anvil effect which would otherwise result from an impact force on an edge or side of the flange 22.

Plunger 16 includes a slot or keyed groove 26 along a portion of its length. A key or pin 28 extends through cap 10 substantially transverse to plunger 16 into slot 26, thereby preventing rotation of plunger 16 in cap 10 while allowing free axial sliding movement.

A heavy mass hammer 30 is located within housing 2. Hammer 30 has an internal axial opening or passage 32 therethrough including lower, middle and upper portions 34, 36, and 38, respectively, having different diameters and into which end 19 of plunger 16 extends. The junction between lower section 34 and middle section 36 comprises a shoulder 40 about the periphery of passage 32. Shoulder 40 has a conical tapered configuration to match that of side 24 of flange 22. Shoulder 40 is the portion of hammer 30 which impacts plunger 16.

A coil return spring 42 surrounds the part of plunger end 19 within portions 34 and 36 of passage 32. Spring 42 abuts a shoulder 44 at the junction of portions 36 and 38 and also abuts surface 24 of flange 22. When plunger 16 is pushed upward through passage 32, return spring 42 is compressed and thereby tends to return plunger 16 to its initial position with flange 22 contacting cap 10.

Hammer 30 includes a lip or flange 46 about its lower edge. A relatively large or heavy coil spring 50, substantially stronger than return spring 42, abuts flange 46 and extends upward about the entire remaining length of hammer 30. Spring 50 abuts cap 8 at the top of housing 2 so that spring 50 is compressed between cap 8 and flange 46 when hammer 30 is pushed upward with respect to housing 2.

A circumferential groove 52 is formed about the upper exterior of hammer 30 and includes a slot or wedge portion 54 extending through the wall of hammer 30 into passage portion 38. A trigger or sear 56 is slidably mounted in slot 54. Sear 56 includes a cam or wedge surface 58 about the upper portion of its inner edge. A spring clip 60 is mounted in groove and about sear 56 to resiliently urge sear 56 to extend into passage 38. In this position sear 56 contacts the upper end 19 of plunger 16 to prevent plunger 16 from moving any substantial distance upward with respect to hammer 30.

When a manual force is applied to handle 2 in a direction to cause seating and trimming of wires or mounting of connector blocks engaged by head 20, i.e., in the direction of arrow 59, end 19 of plunger 16 contacts trigger 56 to prevent further movement of plunger 16 upward through passage 32. Further application of force pushes hammer 30 and plunger 16 upward in housing 2 to compress spring 50. When the top end of hammer 30 reaches cap 8, spring 50 is nearly fully compressed. At this point, pin 12 on cap 8 engages the cam surface 58 of trigger 56 thereby camming or pushing trigger 56 aside out of passage 38. When trigger 56 is pushed aside a sufficient distance, the end 19 of plunger 16 can get by trigger 56 allowing the compressed spring 50 to drive hammer 30 downward with respect to plunger 16 so that shoulder 40 impacts surface 24. This impact is transmitted to head 20 for the seating, trimming, et cetera operations. Upon removal of the force from handle 2, return spring 42 returns plunger 16 to its initial position for the next stroke.

The described impact mechanism has significant advantages over those in the prior art. The placement of substantially the entire length of hammer 30 within power spring 50 allows a much larger hammer and a longer spring to be used thereby providing substantially greater impact forces. The placement of the return spring 42 and impact surfaces 24 and 40 internal to hammer 30 is also significant. This new arrangement of the parts of the impact mechanism provides the greatly increased impact forces previously mentioned without significant increases in the overall size and length of tool 101 as compared with prior art tools providing much lower forces.

Head 20 advantageously comprises a holder or housing 70 which mounts to end 18 of plunger 16 by screw threads or the like. Holder 70 includes two substantially parallel sides 72 having hooks or flanges 74 on the bottom edges thereof extending toward each other. Inserts 76 such as cutting devices, seating devices or combinations thereof are removably inserted into the ends of holder 70 and held therein by flanges 74 engaging grooves 78 or the like in inserts 76. Thus various inserts tailored for specific operations such as seating or trimming conductors can be used in tool 101.

A pad 80 of resilient energy absorbing material such as neoprene rubber is placed between insert 76 and the top of holder 70. This pad absorbs excessive forces in certain applications of tool 101. For example, tool 101 can be used to seat wires in both rigidly mounted and flexibly mounted index strips. More energy is required in the latter case because energy is absorbed by the flexing of the index strip support. Accordingly, tool 101 is designed to provide the required force level for the maximum expected deflection. If tool 101 is subsequently used on a rigidly mounted index strip very little energy would be absorbed by the index strip support. Therefore, the tool's output force level would increase. This excess force would then compress pad 80 absorbing the excess energy, keeping the force at a safe level so as not to damage the connector blocks. As an alternative, the output forces of tool 101 could be made adjustable by making the position of cap 8 within housing 2 variable to thereby control the amount of compression of spring 50 prior to the triggering by pin 12 on cap 8.

FIG. 2 is a perspective view of an insert for use in head 20 and adapted for simultaneously seating five conductor pairs in the index strip of the previously mentioned 88-type connector and also adapted for pushing or mounting a five pair connector block onto the index strip after the wires have been seated therein. Insert 76 includes a body 90 of material such as plastic having a groove 92 separating two sides 94. Mounting slots 96 on the outside of sides 94 are used for mounting insert 76 in holder 20 as shown in FIG. 1. Pairs of fingers or flanges 98 extend from sides 94 toward each other. When insert 76 is inserted over an index strip of an 88-type connector, fingers 98 push the wires previously laid in the index strip into the bifurcated terminals of the strip in response to the impacting of plunger 16 by hammer 30. The connecting blocks used in the 88-type connectors can also be held between fingers 98 and seated or pushed onto the index strip upon the impacting of plunger 16. Fingers 98 can comprise an integral part of body 90 or can comprise inserts mounted in body 90.

An insert 76 for simultaneously seating and trimming five pairs of conductors as well as seating connecting blocks is shown in FIG. 3. This insert is substantially the same as that shown in FIG. 2 with the addition of cutters or blades 99 along the top edges of fingers on one side of body 90. Cutters advantageously are metal inserts which are isolated from each other to prevent any shorting between wire pairs being trimmed. When wires have been seated in the index strip by fingers they are essentially bottomed in the bifurcated terminals so that cutters 99 can trim the ends of the wires extending from one side of the index strip to a uniform length. The impact mechanism of this invention provides sufficient force to perform both the seating and trimming with a single stroke.

While the invention has been described with respect to specific embodiments thereof, various modifications might be made thereto without departing from its spirit and scope. For example, various types of heads other than those illustrated could be configured so that the tools would make operations easier and more efficient.

Claims

What is claimed is:

1. A tool adapted for terminating wires in bifurcated terminals comprising a head for contacting said wires, a plunger on which said head is mounted for moving said head with respect to said terminals, and an impact mechanism for impacting said plunger to thereby apply forces to said head to terminate said wires characterized in that said impact mechanism includes:

a hammer having an internal passageway therethrough to receive said plunger therein, said plunger includes a flange thereabout and said passageway includes a shoulder around the periphery thereof adapted to impact said flange;

a power spring surrounding substantially the entire length of said hammer for imparting a force to said hammer for impacting said plunger; and

a return spring about said plunger within said passageway for returning said plunger to an initial position after said impacting.

2. Apparatus in accordance with claim 1 wherein said flange and said shoulder have conically tapered mating surfaces whereby the tendency of said flange to deflect when said hammer impacts said plunger is reduced.

3. Apparatus in accordance with claim 1 wherein said head includes:

a holder mounted on said plunger;

an insert detachably mounted in said holder and including a body adapted for insertion over said bifurcated terminals, and fingers extending from said body to contact said wires in said terminals, said fingers being responsive to said impacting of said plunger for seating said wires in said terminals.

4. Apparatus in accordance with claim 3 wherein said body includes first and second substantially parallel sides separated by a groove into which said terminals fit when said body is inserted over said terminals, said fingers comprise opposing pairs of said fingers extending from said sides into said groove whereby a respective said wire is contacted on both sides of said terminal.

5. Apparatus in accordance with claim 4 further including cutting means associated with each of said fingers along one of said sides, said cutting means being adapted for severing said wires whereby said wires can be seated in said terminals and trimmed along one of said sides of said terminals in response to said hammer impacting said plunger.

6. Apparatus in accordance with claim 5 wherein said body includes ten each of said fingers and said cutting means whereby five pairs of said wires can be seated and trimmed simultaneously.

7. Apparatus in accordance with claim 3 wherein said insert includes ten of said fingers whereby five pairs of said wires can be seated simultaneously.

8. Apparatus in accordance with claim 3 wherein said head further includes an energy absorbing pad mounted between said insert and said holder for absorbing excessive energy imparted to said plunger by said impacting.

9. Apparatus in accordance with claim 8 wherein said pad comprises neoprene rubber.

10. Apparatus in accordance with claim 1 including a housing having first and second end caps in in which said impact mechanism is mounted with said plunger extending from an opening in said second end cap;

said hammer comprising a substantially cylindrical hammer having a first flange around a first end thereof adjacent said second end cap;

said power spring extends between said first flange and said first end cap with said hammer substantially surrounded thereby;

trigger means in said hammer extending into said passageway for blocking movement of said plunger through said hammer when a force is applied to said handle to thereby compress said power spring and for releasing said plunger when said power spring is substantially compressed whereby said power spring moves said hammer to impact said plunger; and

said passageway includes a second shoulder therein; said return spring being mounted about said plunger between said second shoulder and said flange so that said return spring is compressed when said plunger is released by said trigger means.

11. A tool adapted for uses such as terminating wires in bifurcated terminals comprising an impact mechanism having a plunger for transmitting forces, a hammer for impacting said plunger to impart forces thereto, a power spring for driving said hammer against said plunger when said power spring is released from a compressed state, trigger means for controlling the compression of said power spring from an initial state to said compressed state and releasing said power spring from said compressed state, and a return spring for returning said tool to said initial state, characterized in that:

said power spring surrounds substantially the entire length of said hammer;

said hammer includes an internal passage therethrough in which a portion of said plunger is received; and

said return spring surrounds said portion of said plunger within said passage.