US3031001A - Tool head with removable dies - Google Patents

Description

April 4, 1962 H. c. STOLTZ 3,031,001

TOOL HEAD WITH REMOVABLE DIES Filed NOV. 23, 1956 2 Sheets-Sheet 1 INVENTOR. Herbert C. Sta/{z ww/ w April 24, 1962 TOOL HEAD WITH REMOVABLE DIES Filed Nov. 23, 1956 2 Sheets-Sheet 2 INVE Herbert C. 6

H. c. STOLTZ 3,031,001

United States Patent 3,031,001 TOOL HEAD WITH REMOVABLE DIES Herbert C. Stoltz, Palmyra, Pa., assignor to AMP Incorporated, Harrisburg, Pa. Filed Nov. 23, 1956, Set. No. 623,957 1 Claim. (Cl. 153-1) This invention relates to hand tools, particularly the type in which a pair of levers or handles are manipulated to cause reciprocation of a movable member towards and away from a fixed member.

An object of the invention is to provide a hand tool incorporating lever or handle means which, upon manipulation thereof, causes reciprocation of a movable member towards and away from a fixed member and in which the stroke or travel of the movable member is relatively long.

A further object is to provide a hand tool incorporating a fixed die and a movable die in which the actuating force is applied along the center lines of the two dies so that the dies move into engagement with each other smoothly and evenly.

A further object of the invention is to provide a hand tool incorporating a pair of dies or the like in which the dies can be quickly and simply removed from the tool to permit rapid interchange of the die set for one of a different size.

A further object of the invention is to provide a hand tool for crimping electrical connectors or the like in which the connector is first flattened to some extent and is thereafter compressed to produce the final crimped form of the connection.

Other objects and attainments of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when taken in conjunction with the drawings in which there is shown and described an illustrative embodiment of the invention; it is to be understood, however, that this embodiment is not intended to be exhaustive nor limiting of the invention but is given for purposes of illustration in order that others skilled in the art may fully understand the invention and the principles thereof and the manner of applying it in practical use so that they may modify it in various forms, each as may be best suited to the conditions of a particular use.

In the drawings:

FIGURE 1 is a plan view, with parts broken away, of a preferred embodiment of the invention.

FIGURE 2 is a plan View of a die set which forms part of the invention.

FIGURE 3 is a view taken along the Lines III-11! of FIGURE 2.

FIGURE 4 is a fragmentary view showing the tool head and illustrating the manner in which the fixed die is removed therefrom.

FIGURE 5 is an enlarged perspective view of a locking pin by means of which the movable die is secured within the tool head.

FIGURE 6 is a greatly enlarged fragmentary view showing the manner in which the pin of FIGURE 5 retains the movable die within the tool.

FIGURES 7 and 8 are fragmentary views illustrating the manner in which the movable die is removed from and locked to the movable die carrier, FIGURE 8 being taken along the lines 8-4! of FIGURE 6.

FIGURES 9a, 9b, 9c are a series of fragmentary views illustrating the crimping of an electrical terminal with the embodiment of the tool herein disclosed.

FIGURE 10 presents views of a connector of a type with which the disclosed embodiment of the invention is usable.

FIGURE 11 is a perspective view of an electrical conice nection made with the instant embodiment of the invention.

In the disclosed embodiment of the invention, the reference numeral 2 denotes a tool head comprising a pair of substantially similar plates 4, 6 which are enlarged at their lower end (as viewed in FIGURE 1) and which are maintained in spaced relationship to each other by means of a pair of spacer blocks 12. These spacer blocks are secured by fasteners 8 to the plates 4, =6 and provide 0pposed hearing or guide surfaces 10 which define the path of reciprocation of a reciprocable die carrier as described below. An elongated aperture 5 in plate 6 is provided for the purpose of permitting the positioning of a terminal between the plates, as will subsequently be described, and a smaller aperture 7 in alignment with aperture 5 is provided in plate 4.

A pair of handles or levers 14 are pivotally mounted on pins 16 which extend between plates 4-, 6 on opposite sides of the enlarged lower end thereof. These handles or levers are preferably of channel shaped or U-shaped cross section and are received between the opposed faces of the plates. Torsion springs are provided on pivotal axes 16 and each provides a first arm 17 which bears against a bevel surface 20 on spacer blocks 12 and a second arm 18 of the springs bears against the levers or handles 14- on the inside thereof. These springs normally bias the levers away from each other, however, the levers can be manually closed against the force of the springs. A rack bar 24 is pivotally connected to one of the handles intermediate the ends thereof and engages a ratcheting mechanism 22 integral with the other one of the handles. This ratcheting mechanism may take the form of the ratcheting mechanism shown in the US. patent to Carlson No. 2,618,993 issued November 25, 1952, and need not be described in further detail here. It is sufiicient to say that ratcheting mechanisms in hand tools of this type are provided for the purpose of insuring complete closure of the dies during a given crimping operation by preventing return of the handles from a partially closed position before the handles are fully closed and the dies are completely bottomed.

A movable die carrier 2-6 is received within the tool head and between the opposed faces of spacer blocks 12 for reciprocation toward and away from a fixed die as described below mounted in the top of the tool. This movable die carrier is bifurcated at its lower end and provides a pin 28 extending through the bifurcated portion which receives one end of each of a pair of links 34 These links are pivoted at their opposite ends each to one of the handles or levers 14 so that if the handles are moved through an arcuate path about their pivot points 16 away from each other from the position shown in FIGURE 1, the movable die carrier will be retracted downwardly from the position shown in this figure. As the handles are moved toward each other from the open position, the die carrier is moved upwardly as viewed in FIGURE 1 to cause the movable die to be brought into engagement with the fixed die. Advantageously, a pin 32 is provided extending between plates 4, 6 near the lower end thereof and in such a position that the closure of the handles is prevented from proceeding beyond the point at which the dies are engaged. This pin also acts as a stop to prevent the handles from moving apart substantially beyond the point at which the terminal to be crimped can be inserted. The pin is positioned between links 30 and acts as a stop when engaged by these links as shown in FIGURE 4.

Movable die carrier 26- is slotted on its 1 1 1 61 edge, which slot receives an extension 48 on a movable die 46, FIGURE 3. It is desirable that this die be readily removable from the tool in order that it might be replaced with the die of a diflerent size or type and to this end an opening 50 is provided in extension 48, which opening is, in general, similar to a keyhole in that it provides a restricted portion or slot which communicates with a generally circular bore portion.

Movable die 46 is removably secured to the die carrier by means of a locking pin 41, FIGURE 5, which extends through the slotted edge portion of movable die carrier 26. This locking pin is enlarged at one end 34 and provides a ker-f or slot 36 for the accommodation of a screw driver head or similar tool. The opposite end of the locking pin is of reduced diameter as indicated at 38 and the end is upset as indicated at 40 so that the pin is retained within the die carrier. The central portion of the pin intermediate its ends, which is received within the slot in the upper portion of the movable die carrier, provides a pair of substantially parallel flattened sides 44 and arcuate end portions 42 constituting segments of a circle which in the disclosed embodiment has substantially the same diameter as the enlarged end 34 of the pm.

As shown in FIGURES 7 and 8, movable die 46' is secured to the movable die carrier by first rotating the locking pin so that the flattened sidewalls extend substantially normally of the center line of the die carrier. Thereafter, the movable die 46 is slipped down over the pin until the lower end of extension 48 rests on the bottom of the slot in the movable die carrier and the axis of pin extends centrally through the bore portion of opening 50. After the movable die has been thus seated in the die carrier, pin 41 is rotated, preferably through an angle of 90 in either direction, by means of a screw driver or other appropriate tool. When this pin is thus rotated as shown in FIGURE 8 the arcuate end sections 42 of the pin bear against the surface of the circular portion of opening 50 and, since the intermediate portion of the pin is oriented with the long dimension extending normally of the entrance to opening 50, the movable die is securely locked to the die carrier.

Movable die "46 provides an anvil portion 52 shown in FIGURE 2, which enters a complementary portion of an upper or fixed die 54. The configuration of the anvil portion of the movable die and the complementary opening in the fixed die are particularly designed for the purpose of forming a crimp involving a shielded conductor and a grounding wire described below. The dies themselves, however, might take any one of a variety of forms depending upon the particular operation being carried out. In any event, it is also desirable that fixed die 54 he replaceable, as described below, in order to permit the tool to be used for a variety of wire sizes or crimp types.

Fixed die '54 is securely locked in its position in the tool head by means of a pair of recesses 56 provided on its opposite sides, which recesses receive the teeth or lugs 60 of pivoted latches 58. These latches are pivoted intermediate their ends on pins 59 and are bifurcated on one end 62 for the accommodation of torsion springs 61, the helical portions of which encircle the pins. As shown best in FIGURE 4, one arm of each of these springs bears against an extension of one of the blocks 12 while the end of the other arm is twisted around the end of the bifurcated end 62 of its respective latch. These springs thus normally bias the latches towards each other and into engagement with fixed die 54 although the latches can be pivotally moved out of engagement with the die against the force of the springs as shown in FIGURE 4. To this end extensions 62 function as finger pieces so that the operator with one hand can press the lower ends of the latches inwardly thereby to swing the teeth 60 out of engagement with the fixed die 54.

From the foregoing description it will be apparent that the die set provided in the tool can be replaced with one of difierent size or type in a very short time by even an unskilled operator. Replacement of the die set merely involves first that the latches or levers 58 be depressed on their lower ends 62 to disengage teeth from the fixed die. Thereafter, the fixed die can be removed from the tool by merely pulling upwardly on it as viewed in FIG- URE l or reversing the tool and allowing the die to fall out from between the latches. The lower die can then be removed by merely rotating the pin 41 through 90 and again sliding the die upwardly relative to the tool head.

The disclosed embodiment of the tool, as previously mentioned, is particularly designed for connecting grounding wires to the shielding of shielded conductors. Such a connection is shown in FIGURE 10 in the uncrimped condition and in FIGURE 11 in the crimped condition. Connector 7ain the uncrimped condition comprises an inner cylindrical portion 76 on an outer cylindrical portion 78, which cylindrical portions are connected at one corresponding end, as indicated at 80. One or more apertures or openings may be provided in the connecting portion 8:), as in the disclosed embodiment, for the purpose of inspection of the finished crimp or for receiving the end of a grounding wire as is explained in the copending application of Edgar Forney, Serial Number 583,080, filed May 8, 1956, for Shielded Braid Terminator. Outer cylindrical portion 78 is generally of oval or elliptical shape in cross section (although not necessarily a true mathematical ellipse) and is cut away at one end on each side as indicated at 81 to facilitate collapse of the terminal upon crimping as explained below.

Referring now to the crimped connection of FIGURE ll, the reference numeral 66 denotes the metallic conducting core of the wire over which is provided an insulating cover 68. Metallic braid shielding 70 is positioned over insulation 66 and one or more ground wires 72 is crimped to the metallic braid in the crimped connector 74. In crimping terminals of this type, the braiding 73* on the conductor is stripped back a sufiicient distance, and the insulated conductor thus exposed is passed through the inner cylindrical portion 76. The braiding is then positioned around this inner cylindrical portion 76 and between it and the outer cylindrical portion 78. The connector is then inserted through aperture 5 in plate 6 and positioned on the movable die as shown in 'FIGURE 9a. The portion 68 of the conductor extends through aperture 7 in plate 4, which aperture should not be sufliciently large to permit passage of the terminal itself. Thereafter, the handles are closed to force the connector upwardly into the more confined section of the fixed die with concomitant flattening of the terminal whereby the braiding is pinched between the outer and the inner cylindrical portions. After the terminal has been pushed to the top of the reduced portion of the fixed die, the grounding wire is inserted between the inner and outer cylindrical portions 76, 78, and the tool handles or levers are closed further to cause confinement and compression of the terminal to produce the termination shown in FIGURE 11. During this final crimping the terminal is collapsed along its major axis (as viewed in cross section) to produce the connection shown in FIGURE 11.

The linkage of the instant tool is particularly useful for making crimps of the type shown in FIGURE 9 for the reason that a relatively long travel of the movable die relative to the fixed die is desirable in order that the terminal 74 will be flattened or elongated during the initial stage of the crimping. It has been found that other types of conventional hand tools do not provide the travel necessary to achieve this efiect, however, with the linkage shown in FIGURE 1, movable die 46 moves a substantial distance relative to the fixed die for a single stroke of the handles during which the flattening operation illustrated in FIGURES 9a-9c is achieved.

A further advantage of the instant invention is that the dies are centrally mounted in the tool head and the loading on the dies is exactly symmetrical about the center line of the tool. This arrangement avoids any tendency of the dies to be misaligned or cocked during the crimping operation as is liable to happen where the dies are not directly on one side or the other of the movable member of the die set to which the crimping force is applied.

From the foregoing it will be apparent that the instant invention permits rapid changing of the die wherever the occasion may require it and secure locking of the dies within the tool head. Additionally, the invention provides a comparatively long stroke in the movable member relative to the fixed member for a given travel of the handles.

I claim:

In a tool head incorporating a pair of dies, at least one of said dies being movable relatively towards and away from the other of said dies, the improvement comprising: a pair of latches pivotally mounted on said head, one of said latches being mounted on each side of one of said dies, biasing means normally biasing said latches into engagement with said one die to lock said one die within said tool head, said latches being pivotally movable out of engagement with said one die against the force of said biasing means thereby to permit removal of said one die, a locking pin rotatably mounted within said tool head and having a locking portion comprising a pair of flat parallel sides and arcuate ends, said locking portion having a length as measured between said ends greater than its width as measured between said sides, the other one of said dies providing a bore having a diameter substantially equal to said length of the locking portion, and a slot in said other die having a width equal to the width of said locking portion, said slot communicating with said bore and extending to an edge of said other die, said pin extending through said bore with said locking portion disposed therein and having its length as measured between said ends extending angularly of said slot thereby to secure said other die within said tool head, and said other die being removable from said tool head upon rotation of said pin to align the sides thereof with said slot.

References Cited in the file of this patent UNITED STATES PATENTS 242,142 Leval-ley May 31, 1881 803,840 Miller Nov. 7, 1905 842,173 Carman Jan. 29, 1907 1,392,238 Stewart Sept. 27, 1921 1,475,273 Bernard Nov. 27, 1923 2,439,071 Basham Apr. 6, 1948 2,457,538 Dupre Dec. 28, 1948 2,682,414 Richardson June 29, 1954 2,729,995 Friedman et a1. Jan. 10, 1956 2,765,019 Evans Oct. 2, 1956 2,848,915 Aitken Aug. 26, 1958 FOREIGN PATENTS 274,720 Great Britain July 28, 1927

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