US2772715A - Crimping tool - Google Patents

Description

Dec.` 4, 1956 K. L. NEIJSTROM ET AL CRIMPING TOOL Filed March 24, 1954- INVENTORS KENNETH L. Ns/J'JTROM KENNETH E. PETERsoN WILLIAM 5J "wir United States Patent O CRIMPING TOOL Kenneth L. Neijstrom,5 Camp Hill, Kenneth E. Peterson,

New Cumberland,.and. William-R. Evans, Oberlin, Pa., assignors to Aircraft-Marinev Prducts,. Inc., Hams-.-

This inventionrelates. primarily'to. the. field. of portable hand-operatedtoolsfor crimping electrical connectors or terminals onto wire conductors.

of wires are unavailable or atl a. distance. a crimping tool embodying the invention may be quickly latched. around a. wire, from onev side of the wire with the crimping dies held firmly andy accurately in` alignmentwith. each other.

When the headislatched, it firmly-engages'. and-.locks itself into a rigidly closed positionzfromfwhichy it cannot.

accidentally becomeV disengaged, prior. to theclosure of the dies. against thev wire. Moreover, the head'. may be readily unlatched. and. automatically swingsI to. full open position by operationrofy a singlelatch.l member.

The present. invention is described as embodied ina.

for repair work and. for installation of. new equipment' and assembly work. In working on existing roverhead or. underground: lines and in many other situationsthere are places where the standing part of the conductory is accessible only from. one side with no ends available over which to slide the tool head. Often the space behind the wire is limited. becausel ofnearby structures, so that it is extremely awkward.: or even impossible to. make4 a satisfactory connection with thetools available today. Wheresucha connection can be made with present tools, it often is .unduly fatiguing to` the operator. The head of. a crimping tool, according to the present invention can be readily ysnapped around thestanding par-t of a wire. with the dies automatically aligned and positionedftofacilitate the making, of a high quality connection without undue strain onthe operator.

In work on large. size wires and cables underk service conditions the connectionsare required tohave a1 high mechanical strength anda. large'current-carryingcapacity. Thus, during the crimping operation, to insure a high quality connection, the. dies must be susceptible: to full closeure relatively easily regardless of the limited. space around thewire or the angle from which the wire must be approached. An advantage of the present invention is-that the diesarealways accuratelylv positionedl and susceptible to full accuratelyalignedclosure.

Among the advantages of: the present. invention is the fact, that. it simplies quick removal of the dies and'. easy replacement by different, sizes or types of dies. Thus, a single tool may be used for several different sizes of wire and for. making different types of connections. Moreover,.,a.single-tool together with a set of dies isrelatively light in weight. so that a lineman can carry them up, a pole or into a manhole and work oni various sizes of cables and make different connections, al1 with the one tool and set of dies.

The invention has par-- ticular utilityA for making connections or repairs in existe4 ing wire installations-and in applications wherey the. ends` The head, ofI

They operation off the hydraulic mechanismice With the latch arrangements disclosed, the dies are positively held in accurate relation to' each other, and the increase of pressure during the crimping operation serves to lock the tool head moreA tightly in correct orientation with respect tothe wire orconnector being crimped.

Another advantage is that thev die; assemblies are: sup ported so as to require only a small clearance between the portion of the wire on which. the work is being per'- formed and any nearby structures, for: example, suchy as the wall of' a manholeor4 a roof truss along which the.

wire is strung. Thus, ini many cases it: isr unnecessary to pry the wire away from the obstruction or. to approachy it from an awkward position.

it is an object of. thel present invention toA provide.. a handy crimping tool capable of producing-thehigh crimping pressures necessary fory work on intermediatel and' large size conductorsv tovproduce. connections. having a.

high mechanical strength and a high electrical performance, and yet one which can be readilyused in crampedl locations and where only small clearances are available around the conductor. beingcrimped.

The various aspects, objects,` and advantages of the present invention will` be. in partpointed `out ancln in part apparent, fromv the. following description taken in-` conjunctionwith the accompanying, drawings, in which:

Figure 1 isa, perspective view of a hydraulically-operated hand tool embodyingfthe present invention;

Figure 2 is aperspective view of: artype ofconnection such. as` can be made by the present invention;

Figure 3 isa. s'ideview, enlarged andrpartially in section, of the, head portion of the toolshown inFigure. 1;

Figure 4 is a side View similar to Figure 3 but with.

the. head. shown ini fullyy open. position;

Figure 5 isa. top viewy of thevhead, shown in Figures 3y and 4, partially in section;

Figure 6 is a. View of portions of the latch andy arm of the tool head ofI Figure 5, further enlarged to show in. detail. the, form. of, the S-curved` engageable latchi'ng surfaces thereof; and..

Figure` 7 showsthese surfacescorrespondingly enlarged and inlatchedengagement with. each other.

The type of tool shownin Figure 1 is adapted t-omake connections of the type formedby telescoping a sleeve or ferrule portion ofy a connector over a bare portion of a wire, and then. crimping` the connector intov a firm mechanical. and. electr-ical bond with the wire. Inv this crimping operation. both? the connector and conductor are placed within they head of the' tool, while'it is in the unlatched position, the headis latched, andthe connection is made by applying a large force to the die pieces, thus crimping the walls of the.. sleeve inwardly against the-conductor,- to make a. connectionA such as that. shown in Figure 2,.for example.v n

The tool, as seen inFigure 1, includesa head portion 10, a body portion 12, a xed handle 1.4 and a movable. handle lhingedfto the body by a. pivot` 18.' Duringa crimping operation. the two handles are moved towardv one another. in av series. of. short pumping strokes causing a large hydraulic force to be built up Within-the body 12 so thata movable die 20 (see- Figure 3) carried by a hydraulically driven ram21. is forced toward a` lixed die 22 held ina member 2.4.extending across the head of the tool. This member 24A advantageously is hinged to enable it to beswungopen, for reasons discussed below, but during` crimpingoperation is latched squarely across the path of. movable. die 20. so as to` hold die surfaces of the fixed die 22 accurately aligned with respect to the path ofthe die surfaces ofmovable die 2.0.

The member. 24 has.` aV straight intermediate portion- 25 on.which` die 22 isheld and has aside arm 26 with a pair of hinger plates` 28 on its. butt end. These plates 28 are hingedby a pivot bolt 30 to three hinge plates 31, 32, and

33 fixed to one side of the tool head laterally displaced from the path of movable die 20 and arranged so that member 24 can swing out through approximately a 90 angle to a Wide open position, as seen in full lines in Figure 4.

It should be noted that side arm 26 is connected to the intermediate portion of member 24 by a 90 elbow 34 and that, when member 24 is latched closed, this intermediate portion presents an inner die supporting surface extending perpendicularly across the path of die 20. Thus, with member 24 in closed position the fixed die 22 is held by this perpendicular surface squarely and accurately in alignment with movable die 20, while side arm 26 extends out from the frame of the tool head parallel to the direction of the thrust of ram 21 to anchor its side of the intermediate portion of member 24 firmly in place against this thrust.

As shown in Figure 3, hinged member 24 is held in closed position by means of a latch 36 having an S-curved overhanging nose surface 38 on its inner face near its free end, which engages a mating S-curved lip surface 40 on the free end of member 24 opposite to elbow 34. In latched position, latch 36 also extends out from the frame of the tool head parallel to the path of die 22 to anchor its side of the intermediate portion of member 24 iirmly in place against the thrust of ram 21.

The butt end of latch 36 is hingedly secured to the head of the tool by a pair of hinge plates 41 held by a pivot bolt 42 in engagement with three hinge plates 43, 44 and 45 which are fixed to the opposite side of the path of die 20 from the hinge 30 of member 24. Member 24 and latch 36 can be removed by unscrewing their respective pivot bolts 30 and 42 which have screw driver slots in one end and their other ends threaded and screwed into the tiXed outside hinge plates 31 and 43, respectively.

In order to bias the latch 36 inwardly in the direction of the arrow 46 (Figure 3) toward latching position, a pair of small compression springs 48 (see also Figure 5) are set in suitable recesses in the head between the hinge plates 43 and 44, and 44 and 45, respectively. The outer half of the butt end of the latch is chamfered at S to provide a stop so that the latch cannot be swung open farther than necessary for easy operation, i. e., to the dotted line position 52 shown in Figure 4. To facilitate in unlatching the latch and swinging it into open position, a thumb tab 54 is provided on its free end.

Member 24 is biased outwardly in the direction of the arrow 56 toward its open position, by means of a hinge spring 58 which fits into a slot in the center hinge plate 32. This spring passes around the pivot bolt 30, and is held in concentric position on the pivot bolt by a spacer washer 60. The ends of the spring are inserted into hole 62 in the bottom of this slot and another hole 64 in the butt end of the side arm 26 between hinge plates 28. When member 24 is released it automatically swings outwardly approximately 90 away from thel path of the movable die into its full open position, shown by the solid lines in Figure 4.

As mentioned above, among the advantages of the present invention are those provided because the dies can be latched in place around a wire which is already installed. This latching may be readily accomplished in spite of the fact that 'the wire may have only a slight clearance behind it. In its open position member 24 can readily be inserted behind a standing wire even if it is spaced only a short distance away from an obstructing surface such as the wall of a manhole. This is accomplished by inserting the free end of member 24 from one side so that it projects behind the wire with die 22 adjacent the Wire. Then the handles 14 and 16 are swung out away from the wall, and the head is latched with the handles projecting out at right angles to this obstructing surface, thus giving the operator maximum working room.

When latching member 24 `into closed position, the

operation takes place as follows: the latch 36 is allowed to occupy its released inner position, shown in full-lines in Figure 3. The operator then merely swings member 24 in toward closed position against the torque of the spring 58. As the inner corner of the lip surface 40 on the free end of member 24 (see dotted line position in Figure 3) strikes against the surface 38 on the latch 36, the latch is thereby pushed partially open to the dottedline position shown in Figure 3, whereby the tip 68 of lip 40 is enabled to clear the tip 70 of the nose 38 and lip 40 moves into the recess 71 below the nose. The latch 36 then immediately swings back to its former position, so that when member 24 is released, it swings outwardly only a short distance to the full line position shown in Figure 3. In this position the two S-curved surfaces 38 and 44) are fully engaged as shown enlarged in Figure 7. The intermediate portion of member 24 is then held in fixed position by the side member 26 and by the latch 36 with the die 22 squarely across the line of the path of the impression die 20. Member 24 cannot accidentally displace itself prior to the application of the crimping force to the wire because the latch springs 48 continuously urge the latch toward engaged position while the spring 58 continuously urges member 24 towards engaged position.

In unlatching the arm 24, the operator merely presses on the thumb tab 54 moving latch 36 a slight ways outwardly and the S-curved surface 38 cams the free end of member 24 inwardly a small distance to free it to swing out into fully open position.

Among the advantages of this arrangement are those that result from the fact that the member 24 and its latch 36 are biased Iso that when the tool head is closed, the hook surfaces are fully engaged and held engaged under spring pressure so that member 24 is already in its final crimping position even before any crimping pressure is applied to the work. This means that as the crimping force is applied, the S-curved surfaces merely becomes more lirmly engaged but there is no motion of the die 22. Also, following a crimping operation, the operator, can instantly release the dies merely by pulling outwardly on the thumb tab 54.

Another advantage of this arrangement is that the latch 36 is secured to the head of the tool by a hinge structure which is substantially the same as the hinge structure for the side member 26 `of member 24. Thus, under the tremendous forces developed during the crimping operation, both hinges act the same and hold the die 22 in accurate alignment opposite the impression die 20 in spite of any slight elastic deformation of the metal of the tool head due to the tremendous crimping forces involved.

The die 22 is supported on an inner die-supporting surface 72 of the member 24 which is a ground surface accurately spaced from the opposing die-supporting surface 74 of the ram 21. Because of the accuracy of spacing of these two die-supporting surfaces, the amount of crimping obtained with different sets of dies may be regulated by the predetermined spacing of the die face and seating surfaces of the dies themselves rather than by making changes in the tool head itself.

It will be seen that since member 24, when released, automatically swings to the fully open position, it is convenient to remove and replace the dies 20 and 22. The die 22 is held by its stem 76 in a hole 78 in the intermediate portion of member 24 by means of a springbiased ball detent and its base rests against the inner die-supporting surface 72. v Similarly, the die piece 20 is held against the surface 74 by a ball detent (seen in Fig. 3) which engages its die stern projecting into a recess in the ram 21.

In Figures 6 and 7 are shown in detail the forms of the S- curved surfaces 38 and 40. In order to provide a strong holding action, each of these S-curved surfaces has a central inclined portion L 82, which is planar and which is tangent on each side to a cylindrical curve, each theseV curves has a larger radius R'i and the other has asmaller radius R2, the outerv curves forming-the tips`- 681 and 70 of the lip 40 and nose 38, respectively. Thus, when these two surfaces-are engaged, as showrr in Figure 7, the engagement takes place. onlyy along the planar surfaces 82, and in each case the tipis clear of; its associated hollow. Thus, any grit whicht may accidentally have become lodged in these hollows is. cleared so that it will not affect the accuracy ofthe position of member. 24 with respect to the latch 36. This accuracy is important, for it assures the correct positioning of member 24 with respect to the rest of the head of the tool during crimping and hence the correct positioning of the fixed die 22. Thus, the movable die 20 is enabled always to approach the fixed die the predetermined desired :optimum amount to produce the best crimping action for the particular set Iof dies used. It assures that the inner die-supporting surface 72 -of member 24 is always perpendicular to the path of the die 20.

The angle of slope of the inclined planar surfaces 82 may be in the approximate range from to 45 with respect to the perpendicular to the path of die 20. The outer radii R1 may be in the approximate range from .05 to .20 inch, and the inner radii R2 in the approximate range from .03 to .15 inches, with R1 being from about 1.1 to `about 1.5 times R2. In a particular successful tool head the inclined planar surface 82 was at an angle` of 30 and the radius R1 was approximately 1.35 times the radius R2, these radii being .062 and .046 inch, respectively.

With this embodiment shown, the two pivots 30 and 42 are positioned laterally with respect to the center line of the path of the movable die 20, and they are spaced therefrom an equal distance on opposite sides of it. Also,

it should be noted that both of these pivots are positioned away from the plane of the die-supporting surface 72 of member 24 a significant distance in the direction of the die 20, whereby the movable die 20 as it is driven by ram 21 toward its fully crimped position, shown in Figure 3, passes to a piosition intermediate these pivots with the member and latch being relatively unencumbered and projecting out away from the pivots to an easily accessible position.

Moreover, with this arrangement, the free end of member 24 can be easily slipped between an obstruction and the wire to be crimped with no interference from the latch 36. The only space required between an obstruction and the Wire is the thickness of member 24 plus the depth of the fixed die 22.

It is thus seen that we have provided a tool for crimping connectors and terminals that is well adapted to attain the ends and objects hereinbefore set forth, and which is subject to `a variety of modifications -so that it may be best fitted for a particular use. It is to be understood that the description and drawings are for the purpose of illustrating the invention in accordance with the statutory requirements.

We claim: l. In a tool for crimping connectors onto wire wherein a first die is supported in the head of the tool during a crimping operation and a second die in the tool is driven along a path of operation toward said first die, apparatus enabling said dies to be latched into position on opposite sides of the work to be crimped with said dies maintained accurately aligned during the crimping operation comprising a hinged top member for supporting said first die, a first hinge connecting one side of said top member in the head of the tool, said first hinge being spaced laterally to one side of said die path a predetermined distance and enabling said hinged top member to be swung between a closed position in which said first die is in aligned position in said path ahead of said second die, and an open position in which said first die is removed from said path, a

laterally to the other side of 'saidl path from said' firstv hinge' and spaced'the same-predetermined distance from said path as said first hinge, said second hinge enabling said latchtobe swung between a latching position and-an unlatchingA position, tirst spring means coupled betweenV said member andsaid tool head and urging said member to swing from its closed towards-its open position, second springy means coupled between said latch and said toolv head and urging said latch toward'its latching position, saidhingedtop member having on the-opposite side from itsfhi'nge a lip witha convex rounded surface and a first recess adjacent thereto with a concave rounded surface, and a first straight surface therebetween tangent to both of said rounded surfaces, said latch having thereon spaced from its hinge a nose with a convex rounded surface and a second recess adjacent thereto with a concave rounded surface, and a second straight surface therebetween tangent to both of said rounded surfaces of said nose and second recess, both of said convex surfaces having a larger effective radius than said concave surfaces and both of said straight surfaces being equally inclined with respect to said path and in engagement with each other when said apparatus is latched in closed position.

2. In a tool for crimping electrical conductors, of the ty-pe having a die member movable on the tool body toward a die element supported on the tool head, the improvement whereby said die element can be latched in a closed position and is automatically latched and locked in predetermined position on the tool head opposite said die member when it is closed and automatically swings into the fully open position when unlatched, said improvement comprising: a unitary die element support having an L- shape as seen in elevation including a top portion adapted to support said die-element and a side arm integrally attached to said top portion, first pivot means connecting the butt end of said side arm to the tool body at one side thereof, said support being swingable about said first pivot between a closed position in which said top portion is opposite said die member and an open position in which said top portion is offset laterally from the tool body, first spring means urging said unitary die element support toward its open position, said top portion having a first latch surface thereon, a unitary releasable latch, second pivot means connecting said latch to the tool body on the opposite side thereof from said first pivot means, said latch having a second latching surface adapted to overlap and lock with the latch surface of said top portion when closed, and second spring means urging said latch into engaging position with said second latch surface overlapping and locking with said first latch surface to hold said support in its predetermined closed position against the action of said first spring means, whereby said first spring means urges the die element support into tight locking engagement with the latch in the closed position firmly holding the top portion of the die element support in a predetermined position opposite the movable die member and said first spring means urges the die element support into the fully open position when the latch is released.

3. In a tool for crimping electrical conductors, of the type having a die member movable on the tool body toward a die element supported lon the tool head, the improvement whereby said die element can be latched in a closed position and is automatically latched and locked in predetermined position on the tool head opposite said die member when it is closed and automatically swings into the fully open position when unlatched, said improvement comprising: a unitary top portion adapted to support said die element, said top portion having an upper fiat surface, first pivot means having its axis below said top portion and connecting said top portion to the tool body at one side therof, said top portion being swingable about said first pivot between a closed position in which said top portion is opposite said die member and an open position, first spring means urging said unitary top portion toward its open position, said top portion having a first latch surface thereon, a releasable latch movably mounted on the opposite side of the tool body from said first pivot means, said latch having a second latching surface adapted to overlap and lock with the latch surface of said top portion when closed, and second spring means urging said latch into engaging position with said second latch surface overlapping and locking with said first latch surface to hold said support in its predetermined close position against the action of said first spring means, whereby said first spring means urges the top portion into tight locking engagement with the latch in the closed posi- References Cited in the file of this patent UNITED STATES PATENTS 1,547,565 Duda July 28, 1925 1,733,248 Wilson et al Oct. 29, 1929 1,837,689 Sunde Dec. 22, 1931 2,113,087 Jensen Apr. 5, 1938

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