US2933000A

US2933000A - Crimping tool

Info

Publication number: US2933000A
Application number: US705537A
Authority: US
Inventors: Daniel R Wood
Original assignee: General Dynamics Corp
Current assignee: General Dynamics Corp
Priority date: 1957-12-27
Filing date: 1957-12-27
Publication date: 1960-04-19
Anticipated expiration: 1977-04-19

Description

D. R. WOOD CRIMPING TobL April 19, 1960 Filed Dec. 27, 1957 w Rmx?? INVENTGR. DAN/El. l2. Woon BY y c@ @y @im TTGRNEK Unite States CRIMPING TOOL Application December 27, 1957, Serial No. 705,537

8 Claims. (Cl. 81-15) This invention relates to crimping tools and more particularly to crimping tools for symmetrically crimping electrical contact terminals.

Heretofore crimping tools have been used to connect one or more wires together or to an electrical terminal with suiiicient physical and electrical contact as to make soldering unnecessary. These tools, however, require operator judgment in determining either minimum or maximum squeezing eort in the crimping action. This subjects the connection to electrical or mechanical failure if less than minimum pressure is exerted and deformation of the wire receiving barrel and possible loss of tensile strength of the union if excessive pressure is used. In some applications the wire receiving barrel forms the male member of an electrical Contact. If it is deformed or distorted, misalignment will occur. Connector mating problems are increased as well as withdrawal forces in effecting a disconnection. In some crimping tools, limit stops have been used to provide a limit to the deformation of the barrel to adequately eiect a connection without distortion damage to the barrel. However, this solves only half the problem as the operator is still able to exert less than minimum required pressure to provide a connection which is lsubject to failure by coming apart during use.

The crimping tool comprising the present invention includes a series of forming pins or plungers radially movable within an opening in a retainer or plunger body. A cylindrical barrel portion with bared end of a conductor previously inserted therein is placed in the opening at a preselected depth. The forming pins are moved into pressure contact with the outside surface of the barrel at a plurality of radially spaced points, deforming the immediate area Iinto engagement with the bared end of the conductor. A stop limit is provided to limit the crimping eiiect and a ratchet mechanism is provided which prevents release until a minimum crimping effect has taken place. A special plunger tip permits use of the tool for a wide range of conductor sizes at one adjustment. Excessive driving pressure is also eliminated in its operation because of the tip shape, cam action and mechanical advantage improvements.

An object of the present invention is the provision of a crimping tool for symmetrically crimping a conductor receiving member.

Another object is the provision of a crimping tool for crimping a conductor receiving member without excessive distortion of the member or misalignment of its axis.

Another object is the provision of a crimping tool wherein the maximum and minimum amount of crimping action is automatic and not dependent upon operator judgment.

Another object is the provision of an adjustable stop member for properly spacing the crimping indentations from the end of the conductors.

Another object is the provision of a crimping tool which will accommodate a wide range of wire sizes without operator adjustment.

f1; nt

'ice

Other objects and features of the present invention will be readily apparent to those skilled in the art from the following specification and appended drawings wherein is illustrated a preferred form of the invention, and in which:

Fig. l is an elevational View with parts removed and other parts broken away to better show its construction and operation,

Fig. 2 is a partial sectional view taken along the line 2--2 in Fig. l, and

Fig. 3 is a perspective view oi one of the plungers.

Referring now to Fig. l, the preferred embodiment comprises two relatively movable handle members l1 and l2 which are pivotally connected at one of their extremities in a manner to be more fully explained. Handle member ll is generally U-shaped in section and has an enlarged section i3 at its pivotal end. This section has aligned openings la to accommodate fastening units such as bolts 16 or the like when the component parts of the tool are assembled. These openings are arranged symmetrically about and spaced radially from a central opening 17 through which the connector will be inserted in use. Handle member l2 has a structural configuration similar to that of handle member ll. However, member 12 is constructed of solid material, such as by casting, and its enlarged extremity 1S has an opening 19 considerably larger than the openings .14, 17' above mentioned. This opening has its center in axial alignment with the center of opening 17 and has about its periphery a series of cam surfaces 2i.

A cylindrical plunger body 22 is adapted to tit within opening 19 in handle member i2 and to be connected to handle member ll. Openings 14A in body 22 are in alignment with openings 14 in the enlarged section of member il, so that fastening units 16 may be passed therethrough. A central aperture WA in plunger body 22 is in axial alignment with opening 'i7 in handle member ll.. Extending radially from the aperture 17A are a series of passageway/s 23, preferably four in number. These passageways, spaced between pairs of openings 14A, each comprise an opening 24 having parallel walls extending across the thickness of the plunger body, a. main passageway section 26, and a smaller aperture 27 communicating with opening lA. Springs 28 are mounted in the main passageways 26 to urge the plungers 29 outwardly at all times against cam surfaces 21. The plungers 29 will be more fully described with reference to Fig. 3.

it will be readily noted that the relative movement between the unattached ends of handles ll and 12 to ward one another will cause the cam surfaces 2]. to force the plungers 29 into opening 17A against the action of springs 28. When the handle members are moved relatively away from one another, the plungers by action of the springs 28 are maintained in Contact with that part of the cam surfaces 2l which will enable the .plungers 29 to be withdrawn from the opening 17A.

The desired distance the plungers move into the opening 17A depends upon the number and size of the conductors to be united with the connector placed thereover. Since the movement of the plungers is in direct response to the relative movement of the handle members, an arrangement for controlling the maximum and minimum movement of the handles will control the maximum and minimum movement of the plungers. This is accomplished by the stop means and pawl and rack, mechanism mounted in the handles. Near the free end of handle l2 on the inner surface is mounted a nut 31 and pawl release and stop screw 32 threadedly mounted therein. An anvil stop 33 is mounted in alignment therewith on the base portion of handle 11. A trigger plate 34 is mounted intermediate the stop screw 32 and anvil screw when handles 11 and 12 are moved toward each other. It is apparent thatfthe length of screw 32 and the thickness of the anvil will determine the maximum enetration of the tips of plungers 29 into the wall of a connector, or the deformation of the connector walls, placed in the opening 17A. The screw 32 may be adjusted or the anvil stop 33 may be replaced to vary the maximum penetration as desired.

Handle 12 has a reinforcement rib 36 extending along its under side to reinforce itself near its enlarged section 18. Pivotally connected to this rib 36 by means of rack pin 37 is rack 3S. This rack is substantially Llshaped in section, having a base 39 and upturned flanges on each side of a general configuration as shown in Fig. l. The upper edges of these ilanges 41 are suitably notched to provide a ratchet connection with pawl Pawl engaging ears 43 engage pawl 42 to limit the outward relative movement of handles 11 and 12. Pawl 42 is mounted for engagement and disengagement with the notched tianges 41 by the pivotal action of its mounting. The pawl mounting 44 consists of a pair of side plates 46 pivotally mounted to the upstanding walls of handle 11 by pin 47. The pawl 42 interconnects the side plates and maintains them in spaced relation at one end and a pin 48 connects them at another point. Downwardly extending ears 49 on the pawl plates conne the movement of tip 51 of trigger 52 therebetween. Pawl spring 53 urges rotation of the pawl 42 in a counterclockwise direction to maintain contact with the notched flanges 41 to permit inward movement of the handles 11, 12 and to prevent their outward movement. In Fig. 1, however, actuation of the trigger plate 34 is shown, causing panel 42 to be moved clockwise, against the action of spring 53, to its release position. One end of spring 53 is fastened to pin 48 and the other end urges against an inwardly directed ,projection 54 on an inner upstanding wall of handle 11. Trigger -2 is an elongated memberv pivotally mounted by pin 56 to the walls of member 11 and extends to just below pin 48. It supports trigger plate 34 on its outer end.` When the handles 11, 12 are moved together pawl release and stop screw 32 urges trigger plate 34 downwardly in contact with anvil stop 33. Until this limit is reached, pawl 4-2 maintains contact with rack flanges 41 to prevent outward movement of the handles and withdrawal of the plungers 29 from opening 17A. When this limit has been reached, the downward movement of stop screw 32 causes tip 51 of trigger 52 yto move upwardly against pawl pin 48. This, in turn, pivots pawl 42 out of contact with rack 38, permitting the handles to be moved apart and the plungers 29 to be withdrawn from opening 17A. A spacer 57 maintains the walls of handle 11 in xed spaced relationship to prevent damage or inoperativeness of the parts contained therebetween.

In 'order to utilize this tool where various lengths of connectors are to be crimped, this tool is provided with a connector'locating arrangement as shown in Fig. 2. A connector well 58 is secured to a support plate 59 which is 'then fastened to the outer surface of handle 11 over opening 17; The connector well 58 is threaded along its outer surface and has two diametrically opposed longitudinally extending slots 61 communicating with its interior. A connector well stop plate 62 positioned within the well has two ear portions 63 extending through the slots to engage compression spring 64 mounted over the outside of the well. The spring 64 urges the stop plate outwardly until the ear portions 63 abut against thc circular nut 66 threadedly mounted on the exterior surface of the well 5S. This nut Vis knurled and has acircumferential groove 67 thereon for aligning with indicia on the crimping location guide 68 which is mounted longitudinally along the well. VA depth stop guide 69 is mounted internally of the well and is connected to stop plate 62. The desired distance from the end of the conl '4 nector for crimping is achieved by rotating nut 66 until its groove 67 is aligned with the proper indicia on the location guide 68. This connector locating arrangement is described in greater detail in U.S. Patent No. 2,753,742, issuing July l0, 1956, to S. N. Buchanan for Hand Tool for Crimping Electrical Connectors, the only difference being that the spring of Buchanan is mounted internally of the well whereas applicants spring 64 is mounted cx teriorly. Y

Fig. 3 is a perspective view of one of the plungers 29. lts head 71 has

parallel sides

72, 73 which engage parallel walls 24'of passageway 23 in plunger body 22 to prevent rotation of the plunger. The shaft portion '74 is generally round and is adapted for axial movement within aperture 27. The tip 76 is tapered and has two

teeth

77, 73. Tooth 77 is sharper and longer than tooth 78. This tooth design permits one setting for a wide range of conductor sizes without under-crimping small diameter conductors or over-crimping larger diameter conductors. For example, to crimp a connector onto a No. Q2 (small) wire, the four plunger tips must approach each other sutiiciently close so as to force the connector into intimate union with the small wire strands. the punches also approach each other in an identical manner when a large connector and related large wire, such as a No. 12,y is to be crimped. This would cause the longer tooth to seriously weaken the large wire. In order to compensate for this weakness, a second and less severe crimp is produced in the larger size connectors by the shorter and more blunt tooth which is nearer to the open end of the connector barrel.

Logically speaking, the hand force required in closing the handles is proportional to the area of the plunger tip being forced into the connector and deforming the connector and its related conductor. However, if the tips are too narrow the teeth will split the connector,

rather than force the connector and associated conductor into intimate junction, as desired. It has been found that a thickness of .030 to be most suitable. This combination of teeth shapes and thickness has provento produce very good mechanical strength and intimate electrical union for all wire sizes in the range of No. 12 to No. 22 without the necessity for adjustment to'adapt the tool to specific wire sizes.

While certain preferred embodiments of the invention have been specifically disclosed, it is understood that the invention is not limited thereto as many variations will be readily apparent to those skilled in the artand the invention is to be given its broadest possible interpretation within the terms of the ,following claims.

What I claim is:

1. A n improved crimping tool comprising a plunger body, a plurality of plungers mounted therein vfor axial movement in a radial direction, a center transverse opening in said plunger body for receiving a connector to be secured to conductors received therein, said plungers being adaptable for movement into said opening and away therefrom, means for moving said plungers in said radial direction comprising one handle connected to said plunger body, ,a Second handle, an enlarged section attached to `said second handle, an opening in said enlarged section to receive said plunger body, an inner ca m surface on said opening, said plungers contacting said inner Vcam surface and being movable thereby upon actuation of said handles, control means for controlling plunger movement, said control means including a limit stop to limit movement of said handles toward each other and means for assuring a predetermined minimum plunger movement comprising a releasable ratchet movement means on said handles permitting inner movement thereof and preventing separation thereof until a predetermined inward movement has been effected and automatic release means actuated by said limit stop to releasesaid ratchet movement means to thereby permit separation of said handles upon completion of said inner movement.

However,

44A... Ac

2. An improved crimping tool foruse in crimping a barrel onto the end of a connector, said tool including crimping means for eiiecting the crimping and a pair of handles connected to said crimping means for actuation thereby upon movement together of said handles, control means for controlling crimping movement, said control means including a limit stop to limit movement of said handles toward each other and means for assuring a predetermined minimum crimping movement comprising a ratchet movement means on said handles permitting inner movement thereof and preventing separation thereof until a predetermined inward movement has been eifected and automatic release means permitting separation of said handles upon compietion of said inner movement, said ratchet movement means comprising a raclr on one of said handles, and a rack engageable pawl on the other of said handles, said release means being operable by said limit stop to disengage said pawl and rack.

3. An improved crimping tool comprising a plunger body, a plurality of plungers mounted therein for axial movement in a radial direction, a center transverse opening in said plunger body for receiving a connector to be secured to conductors received therein, said plungers being adaptable for movement into said opening and away therefrom, means for moving said plungers in said radial direction comprising one handle connected to said plunger body, a second handle, an enlarged section attached to said second handle, an opening in said enlarged section to receive said plunger body, an inner cam surface on said opening, said plungers contacting said inner cam surface and being movable thereby upon actuation of said handles, control means for controlling plunger movement, said control means including a limit stop to limit movement of said handles toward each other and means for assuring a predetermined minimum plunger movement comprising a rack pivotally mounted on said second handle, said rack having pawl engaging notches thereon, and a pawl pivotally mounted on said one handle, said pawl and rack permitting inward movement thereof and preventing separation thereof until a predetermined inward movement has been effected, and automatic release means disengaging said rack and pawl to permit separation of said handles upon completion of said inner movement, said release means being actuated by said limit stop at the limit of inward movement of said handles.

4. An improved crimping tool comprising a plunger body, a plurality of plungers mounted therein for axial movement in a radial direction, a center transverse opening in said plunger body for receiving a connector to be secured to conductors received therein, said plungers being adaptable for movement into said opening and away therefrom, means for moving said plungers in said radial direction comprising one handle connected to said plunger body, a second handle, an enlarged section attached to said second handle, an opening in said enlarged section to receive said plunger body, an inner cam surface on said opening, said plungers contacting said inner cam surface and being movable thereby upon actuation of said handles, control means for controlling plunger movement, said control means including a stop screw on one of said handles and an aligned anvil stop on the other of said handles to limit movement of said handles toward each other and means for assuring a predetermined minimum plunger movement comprising a rack on said second handle and a raclr engageable pawl on said one handle, said pawl and rack when engaged permitting inward movement of said handles and preventing separation thereof until a predetermined inward movement has been effected and release means permitting separation of said handles upon completion of said inward movement, said release means being actuated by inward movement of said stop screw to disengage said rack and pawl.

5. An improved crimping tool comprising a plunger body, a plurality of plungers mounted therein for axial movement in a radial direction, a center transverse opening in said plunger body for receiving a connector to be secured to conductors received therein, said plungers being adaptable for movement into said opening and away therefrom, means for moving said plungers in said radial direction comprising one handle connected to said plunger body, a second handle, an enlarged section attached to said second handle, an opening in said en and rack permitting inward movement of said handles'` and preventing separation thereof until a predetermined inward movement has been eifected and release means permitting separation of said handles upon completion of said inward movement, said release means including a pivotally mounted lever having one end extending between said anvil stop and said stop screw, the other end of said lever being operable to pivotally move said pawl from contact with said rack when said lever is moved by said stop screw.

6. An improved crimping tool comprising a plunger body, said plunger body having transverseslots spaced about its peripheral edge, a center transverse opening, openings communicating be-tween said slots and said center opening, a plurality of plungers each having a tip, stem and head, said openings receiving said plungers with heads thereof non-rotatably positioned within said slots, said plungers being adaptable for axial movement with said tips moving into said opening and away therefrom, means for moving said plungers radially relative to said opening comprising one handle connected to said plunger body, a second handie, an enlarged section attached to said second handle, an opening in said enlarged section having said plunger body positioned therein, an inner cam surface on said opening, said plungers contacting said inner cam surface and being movable thereby upon actuation of said handles, control means for controlling plunger movement, said control means including a limit stop to limit movement of said handles toward each other and means for assuring a predetermined minimum plunger movement comprising a releasable ratchet movement means on said handles permitting inner movement thereof and preventing separation thereof until a predetermined inward movement has been eiected and automatic release means operable by said limit stop for separation of said handles upon completion of said inner movement,

7. An improved crimping tool comprising a plunger body, said plunger body having transverse slots spaced about its peripheral edge, a center transverse opening, openings communicating between said slots and said center opening, a piurality of plungers each having a tip, stem and head, said openings receiving said plungers with heads thereof non-rotatably positioned Within said slots, said plungers being adaptable for axial movement with said tips moving into said opening and away therefrom, said tips having a pair of teeth thereon, one of said teeth being longer and more pointed than the other of said teeth, said stems being tapered toward said tips such that said tips are of less thickness than said stems, means Jior moving said plungers radially relative to said opening comprising one handle connected to said plunger body, a second handle, an enlarged section attached to said second handle, an opening in said enlarged section having said plunger body positioned therein, an inner cam surface Qn said Opening, said plunsers contacting said inner earn surface and being movable thereby upon actuation of said handles, control means for controlling plunger movement, said control means including a limit stop to limit movement of said handles toward each other and means for assuring a predetermined minimum plunger movement `comprising a releasable ratchet movement means on said handles permitting inner movement thereof and preventing separation thereof until a predetermined inward movement has been eiected and automatie release means operable by said limit stop for separation of said handles upon completion of said inner movement.

8i. An improved crimping tool for use in crimping a barrel onto the end of a connector, said tool including crimping means for eecting the crimping and a pair of handles connected to said crimping means for actuation thereby upon movement together of said handles, control means for controlling crimping movement, said control means including an anvil stop on said one handle and an aligned stop screw on said second handle to limit movement of said handles toward each other and means for assuring a predetermined minimum crimping movement comprising a rack pivotally mounted on said second handle and a rack engageable pawl pivotally mounted on said one handle, said pawl and rack permitting inward movement of said handles and preventing separation thereof until a predetermined inward movement has been effected and release means permitting separation of said handles upon completion of said inward movement, said release means including a pivotally mounted lever having one end extending between said anvil stop and said stop screw, the other end of said lever being operable to pivotally move said pawl from contact with said rack when said lever is moved by said stop screw.

References Cited in the'le of this patent UNITED STATES PATENTS 2,467,012 Deuschle Apr. 12, 1949 2,618,993 Carlson Nov. 25,V 1952 2,696,747 Bergan Dec. 14, 1954 2,704,001 Morse Mar. 15, 1955 2,753,742 Buchanan July 10, 1956