US3673299A

US3673299A - Method of applying sleeves to electrical connectors

Info

Publication number: US3673299A
Application number: US15017A
Authority: US
Inventors: Ray Mervyn Robins
Original assignee: AMP Inc
Current assignee: TE Connectivity Corp
Priority date: 1970-02-27
Filing date: 1970-02-27
Publication date: 1972-06-27
Anticipated expiration: 1989-06-27

Abstract

Electrical connectors are post insulated by cold-forming thereon dielectric sleeves which are connected together in end-to-end strip form as a series of sleeves and this strip of sleeves is fed to a crimping station so that the leading sleeve of the strip is cold-formed over an electrical connector at the crimping station. The strip of sleeves may be made by cutting transverse slots in a plastic tube such as, for example, a tube of polyvinyl chloride.

Description

States atent Unite Robins June 27, 1972 [54] METHOD OF APPLYING SLEEVES TO ELECTRICAL CONNECTORS [72] Inventor: Ray Mervyn Robins, Auburn, New South Wales, Australia [73] Assignee: AMP Incorporated, Harrisburg, Pa.

22 Filed: Feb. 27, 1970 |2l| Appl.No.: 15,017

Related US. Application Data [62] Division of Ser. No. 680,687, Nov. 6, 1967, Pat. No.

[52] US. Cl. ..264/l59, 29/630 A, 29/414, 29/417, 29/517, 264/249 [51] Int. Cl ..B29d 7/16 [58] Field ofSearch "29/203 D, 630 A, 517,417, 29/414; 264/249, 159

[56] References Cited UNITED STATES PATENTS 2,288,918 7,1942 xk ."i773'"1231?!i'.'Tf"I3."l 2[ LA 2,671,889 3/1954 Vickery ..29/630 A X 2,839,824 6/1958 Berg ..29/4l7 2,963,775 12/1960 Chadwick ..29/630 A 2,964,065 12/1960 Harolds0n.... ..264/173 X 2,974,400 3/1961 Sowa ..29/63O A Primary Examiner-Charlie T. Moon Attorney-Curtis, Morris and Safford, William J. Keating, Ronald D. Grefe, Frederick W. Raring, Jay L. Seitchik and John P. Vandenburg [57] ABSTRACT Electrical connectors are post insulated by cold-forming thereon dielectric sleeves which are connected together in end-to-end strip form as a series of sleeves and this strip of sleeves is fed to a crimping station so that the leading sleeve of the strip is cold-formed over an electrical connector at the crimping station. The strip of sleeves may be made by cutting transverse slots in a plastic tube such as, for example, a tube of polyvinyl chloride.

1 Claim, 8 Drawing Figures PATENTEDJUNZY r912 SHEET 5 OF 5 METHOD OF APPLYING SLEEVES TO ELECTRICAL CONNECTORS This application is a division of my earlier filed case, Ser. No. 680,687, filed Nov. 6, 1967, now US. Pat. No. 3,506,41 1.

It is common practice to insulate an electrical connector which has been crimped to the end of a wire, by crimping about the connector a sleeve of insulating material, for example polyvinyl chloride. The sleeve may be fed to the dies of a press for crimping the sleeve to the connector, e.g. from a vibratory hopper. A disadvantage of this known method of insulating an electrical connector is that the sleeve tends to become jammed or misoriented during its passage from the hopper to the dies. A further disadvantage of the method is that the sleeves must be applied to the connector in loosepiece form.

According to one aspect of the invention a method of applying an insulating sleeve to an electrical connector comprises the steps of feeding a series of insulating sleeves connected together in axial alignment to fonn a strip of such sleeves, a sleeve length at a time, towards a crimping station to dispose the leading sleeve of the strip at the crimping station, inserting the connector into the leading sleeve, crimping the leading sleeve to the connector and shearing the leading sleeve from the strip at the crimping station.

The strip of sleeves may readily be formed by cutting transverse slots in a tube of synthetic plastic material, for example unplasticized polyvinyl chloride, the slots being spaced from one another axially along the tube by the desired length of the sleeves. The slots preferably extend perpendicularly to'the axis of the tube. The slots may be cut by the use of a circular saw blade mounted for movement towards and away from the tube and relative to which the tube is fed, for example by a reciprocable feed finger and between guide plates. Since the flexibility of the strip is enhanced by the slots, the strip of sleeves may readily be wound onto a storage spool and fed subsequently to the crimping station by the feed finger conveniently engaging the slots in the tube. A blade for shearing the leading sleeve from the strip may be employed as a stop for limiting the entry of the connector into the sleeve immediately prior to the crimping operation. The feed finger may engage in the slot between the leading and the next adjacent sleeve of the strip to act as a stop to locate the connector immediately prior to the crimping operation.

According to another aspect of the invention, apparatus for crimping insulating sleeves to electrical connectors comprises a press ram, a sleeve-crimping die on the ram and a sleevecrimping anvil, the ram being movable towards the anvil from a top dead center position through a working stroke to cause the die to crimp a sleeve on the anvil to a connector inserted into the sleeve, the ram being then movable through a return stroke, the apparatus further comprising means for feeding a series of insulating sleeves connected together in axial alignment to form a strip of such sleeves, a sleeve length at a time towards the crimping anvil to dispose the leading sleeve of the strip on the crimping anvil, a shear blade mounted on the ram for shearing the leading sleeve from the strip during the working stroke of the ram and a shear blade control mechanism having a first position in which the shear blade lies between the leading sleeve on the anvil and the next adjacent sleeve in the top dead center position of the ram, so that the shear blade acts as a stop for limiting the insertion of the connector into the leading sleeve and a second position in which the shear blade is locked to the ram during the return stroke of the ram so as to move with the ram away from the anvil to permit a next adjacent sleeve to be advanced onto the anvil during the return stroke of the ram.

According to a further aspect of the invention, a machine for producing a series of insulating sleeves connected together in axial alignment to form a strip of such sleeves comprises a first slide carrying a rotatable circular saw blade, means on the first slide for driving the saw blade in continuous rotation, a second slide arranged to be intermittently advanced and retracted a sleeve length at a time along a path extending transversely of the path of movement of the first slide, guide means on the second slide for receiving a length of insulating tubing extending in the direction of movement of the second slide and intersecting the path of movement of the saw blade so that the saw blade can form a transverse slot in the length of tubing during the advance of the first slide, a feed finger on the second slide for engaging the length of tubing so that the length of tubing moves with the second slide during the advance of the second slide, tube stop means for restraining movement of the length of tubing with the second slide during the retraction of the second slide, and means for synchronizing the movements of the first and second slides so that the second slide is stationary during the advance of the first slide.

An object of the invention is to provide a strip of dielectric sleeves and to secure leading sleeves of the strip onto electrical connectors at a station for securing the sleeves onto the electrical connectors.

Another object of the invention is the provision of an apparatus for forming a tube of plastic material having suitable dielectric properties into dielectic sleeves connected together in end-to-end strip form as a series of sleeves.

A further object is to provide apparatus for securing a strip of dielectric sleeves onto electrical connectors to provide post-insulated electrical connectors.

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 are shown and described illustrative embodiments of the invention; it is to be understood, however, that these embodiments are not intended to be exhaustive nor limiting of the invention but are 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.

For a better understanding of the invention, reference will now be made by way of example to the accompanying drawings, in which:

FIG. 1 is a perspective view of a machine for producing a strip of insulating sleeves connected together in axial alignment;

FIG. 2 is a sectional view taken on the lines 2-2 of FIG. 1, and illustrating the operation of the machine;

FIG. 3 is a fragmentary perspective view of a strip of insulating sleeves produced by the machine of FIGS. 1 and 2;

FIG. 4 is a fragmentary perspective view of press apparatus for crimping the insulating sleeves to electrical connectors, the apparatus being illustrated during the return stroke of the press ram thereof;

FIG. 5 is a longitudinal cross-sectional view of the apparatus of FIG. 4 but illustrating the press ram in its top dead center position;

FIG. 6A is an elevational view taken on the lines 6A-6A of FIG. 5;

FIG. 6B is a similar view to that of FIG. 6A but with the press ram in the position of FIG. 4; and

FIG. 7 is a view similar to FIG. 5 showing the press ram at the end of its working stroke.

Reference will now be made to FIGS. 1 and 2. The machine comprises a base plate 2 upon which are guides 4 laterally confining a first slide 6 urged rightwardly (as seen in FIG. 1) by compression springs 8 housed in bores in one end of the slide 6 and engaging a stop block 10 fixed to the plate 2. A pneumatic motor 12 driving a cutting member such as a circular saw blade 14 is fixed to the other end of the slide 6. As shown in FIG. 2, a rod 16 extends vertically from beneath the slide 6 and through a slot (not shown) in the plate 2. The rod 16 carries a roller 18 engaged by a cam wheel 20 driven in rotation by means, for example an electric motor (not shown) through a shaft 22. Also mounted on the plate 2 is a second slide 24 reciprocable in a direction at right-angles to the path of movement of the slide 6 between guide plates 26. A pair of compression springs 28 (only one of which is shown) housed in bores in the slide 24 engage a further stop block 30 to urge the slide 24 leftwardly (as seen in FIG. 2). The slide 24 has an axial channel 32 formed by

guide plates

34 and 36 which are divided at right angles to the channel 32 to provide a further channel 38 in alignment with the saw blade 14. Tiltably mounted on the plate 34 is a feed finger 40 having a working tip 42 biased towards the base of the channel 32. Mounted on the

plates

34 and 36 to the right (as seen in FIG. 1) of the saw blade 14 is a pressure pad 44 urged downwardly (as seen in FIGS. 1 and 2) by springs 46 and having a rounded edge 48 by which the pad 44 can be lifted against the action of the springs 46. A further rod 50 depending from the slide 24 through a slot 52 in the plate 2 is engageable by the cam wheel 20 through a further roller 54. The

rods

16 and 50 have flats 56 for use in screwing the rods into their respective slides.

Adjacent the block 30 is a tube stop block 58 having a through aperture 60 into which extends a stop jaw 62 pivotable about a pin 64 and being urged by a spring 66 in an anticlockwise (as seen in FIG. 2) sense of rotation about the pin 64.

The cam wheel 20 is so arranged that the machine carries out the following operating cycle when the means driving the cam wheel 20 is started.

The slide 6 is first advanced by the springs 8 rightwardly (as seen in FIG. 1) so that the saw blade 14, which rotates continuously, enters the channel 38, the slide 6 being subsequently retracted by the cam wheel 20 to its initial position, after which the cam wheel 20 retracts the slide 24 rightwardly (as seen in FIG. 1) against the action of the springs 28, by which the slide 24 is then advanced towards its initial position.

In operation, a length of thermoplastic tubing T, e.g. of unplasticized polyvinyl chloride is fed through the aperture 60 of the block 58 from the left-hand (as seen in FIG. 2) end of the aperture 60 to drive the jaw 62 in a clockwise (as seen in FIG. 2) sense of rotation against the action of the spring 66, the length of tubing T being passed through the channel 32 beneath the pressure pad 44 and feed finger 40, as shown in FIG. 2. The pad 44 and finger 40 are lifted manually to permit passage of the length of tubing T through the channel 32 and are subsequently released.

The means driving the cam wheel 20 is now started, eg by actuating a pedal switch (not shown) so that the slide 6 is advanced to cause the saw blade 14 to enter the channel 38 so as to cut a transverse slot S in the length of tubing T to leave a slug SI. of tube material at the base of the slot S. The slide 6 is then retracted by the cam wheel 20 and the slide 24 is moved by the cam wheel 20 rightwardly (as seen in FIG. 1) so that the working tip 42 of the feed finger 40 lies on the length of tubing T slightly to the right (as seen in FIG. 2) of the slot S that has just been formed by the saw blade 14. The action of the jaw 62 prevents the length of tubing T from being retracted with the slide 24. As the slide 24 is now advanced under the action of the springs 28, the tip 42 of the feed finger 40 engages in the newly formed slot S so that the feed finger 40 drives the length of tubing T leftwardly (as seen in FIG. 2) after which the saw blade 14 is again advanced to slot the length of tubing T at a position back from the slot S first formed, as the working cycle of the machine is repeated.

It will be apparent that the machine just described produces a continuous strip ST of insulating sleeves SV (see FIG. 3) connected together in axial alignment, each sleeve SV being connected to the next adjacent sleeve SV by a slug SL of the material of the length of tubing T.

Apparatus for crimping the sleeves SV to electrical connectors will now be described with reference to FIGS. 4 to 7. The apparatus comprises a press ram 70 (only part of which is shown) arranged to be driven in vertical reciprocation through a stroke of predetermined length by an electric motor (not shown) through a toggle linkage (not shown). The electric motor is actuable by depressing a pedal switch (not shown) through a one-shot clutch (not shown) so that upon actuation of the pedal switch the ram 70 is automatically driven through a downward or working stroke and an upward or return stroke after which the ram 70 remains stationary in its top dead center position until the pedal switch is next depressed.

The ram 70 carries sleeve crimping dies 72 and 74 having working

surfaces

73 and 75, and a sleeve shear blade holder 76 in which is mounted a shear blade 78 slidably arranged between the holder 76 and a cover plate 80 having a central downwardly opening slot 82. The shear blade 78 has a shearing edge 84 bridging a pair of spaced depending legs 86 of the shear blade 78. A pin 88 extending at right-angles from the shear blade 78 projects through the slot 82 in the cover plate 80 leftwardly (as seen in FIGS. 5 and 7). A two-armed latch member 90 is pivotally mounted on a pin 92 on a projection 94 of the shear blade holder 76 and is urged in a clockwise (as seen in FIGS. 6A and 6B) sense of rotation about the pin 92 by a spring 96 attached at one end to the member 90 and at the other to the cover plate 80 so that the left-hand (as seen in FIGS. 6A and 6B) arm of the member 90 bears against the pin 88. On the opposite side of the pin 92 to the spring 96, the member 90 carries a pin 97 which projects laterally from the member 90. A stop pin 98 projects from a plate 100 which is mounted, for adjustment in a left to right (as seen in FIGS. 6A and 6B) direction on a portion 101 of the frame of the apparatus which frame is otherwise not shown. The shear blade holder 76 and the member 90 thereon are thus movable with the ram 70 relative to the stop pin 98.

The apparatus further comprises a press bed portion including a mounting block 102 carrying a strip feed plate 104 on which are strip guide plates 106 defining a strip feed channel 108 (FIG. 4). Also mounted on the plate 104 is a pressure pad 110 urged downwardly (as seen in FIG. 4) by springs 112. A strip feed finger 114 having a working tip 116 is urged downwardly (as seen in FIGS. 4, 5 and 7) by a spring (not shown), the feed finger 114 being arranged to be driven in left-to-right (as seen in FIGS. 4, 5 and 7) reciprocating motion by means (not shown) for example a piston and cylinder device.

Also mounted on the block 102 are sleeve crimping anvils 1 18 and 120 having working

surfaces

122 and 124 respectively, in alignment with the working

surfaces

73 and 75 respectively, of the dies 72 and 74. Adjacent the anvil 120 is a first shear plate 126 spaced from a second shear plate 128 by separator plates 130 (only one of which is shown) to define a space 132 into which the legs 86 of the shear blade 78 extend.

The apparatus has a rotary storage spool (not shown) mounted on the frame of the apparatus or upon a separate stand (not shown) about which a spool or strip ST of sleeves SV produced by the machine of FIGS. 1 and 2 is wound. Also, as the strip of sleeves is being made by the machine of FIGS. 1 and 2, the strip can be simultaneously fed into the crimping apparatus of FIGS. 4-7.

With the ram 70 in its top dead center position as shown in FIG. 5, the end of the strip ST on the spool is laid into the channel 108 beneath the pad 110 which is raised manually to permit this. The end of the strip ST is further led beneath the working tip 116 of the feed finger 114 which is also raised manually to allow passage of the strip. The pad I 10 and finger 114 are then released so as to be returned to the position of FIG. 5 under the action of their springs. The shear blade 78 is now raised manually from the position of FIG. 6A to that of FIG. 6B and the end of the strip ST is passed beneath the edge 84 of the blade 78 so that the leading sleeve SV of the strip rests upon the plate 126 and upon the working

surfaces

122 and 124 of the anvils as shown in FIG. 5. The shear blade 78 is then released and falls back so as to extend into the slot S between the leading sleeve SV and the next adjacent sleeve SV, the edge 84 of the blade 78 resting upon the slug SL between these sleeves. The apparatus is now ready for operation.

An electrical connector C for example an electrical tab receptacle, already crimped to a wire W is inserted into the leading sleeve SV until the connector C engages the shear plate 78 which as aforesaid extends into the slot S between the sleeve SV and the next adjacent sleeve SV. The connector is accordingly precisely positioned axially within the sleeve SV.

Upon actuation of the pedal switch the ram 70 is driven through a working stroke so that the sleeve SV is crimped about the connector C between the working

surfaces

73 and 75 of the crimping dies 72 and 74 and the working

surfaces

122 and 124 of the

anvils

118 and 120. During the working stroke, the shear blade holder 76 descends with the ram 70 so that the holder 76 moves downwardly relative to the shear blade 78 causing the shear blade 78 to bottom against the holder 76 whereby the shear blade 78 is driven downwardly with the holder 76 to cause the shearing edge 84 of the blade 78 to shear the slug SL from between the leading sleeve SV and the next adjacent sleeve SV in co-operation with the

shear plates

126 and 128. The edge 84 thus enters the space 132 as shown in FIG. 7.

The ram 70 now automatically carries out its return stroke under the action of the one-shot clutch. As the ram 70 rises, the shear blade holder 76 rising with the ram 70, the latch member 90 urges, under the action of its spring 96, the pin 88 on the shear blade 78 upwardly (as seen in FIG. 68) so that the shear blade 78 is retained in its bottomed position against the holder 76 and thus rises with the holder 76 so that the edge 84 of the shear blade 78 is raised above the next adjacent sleeve SV and is thus positioned as shown in FIGS. 4 and 6B. The pin 97 on the latch member 90 engages a microswitch (not shown) to actuate the driving means for the feed finger 114 so that the feed finger carries out a working or leftward (as seen in FlG. 5) stroke to advance the next adjacent sleeve SV under the edge 84 and between the legs 86 to push the sleeve SV off the anvils and to take up the position originally occupied by the sleeve SV. As the ram 70 continues its upward travel, the latch member 90 strikes the stop pin 98 so that the latch member 90 is rotated from the position of FIG. 6B to that of FIG. 6A against the action of the spring 96 to permit the shear blade 78 to fall back to the position of FIGS.

5 and 6A. The stop 91 engages a further micro-switch (not shown), causing the feed finger 114 to be retracted to its initial position as shown in FIG. 5. The microswitches are arranged to be inoperative during the working stroke of the ram 70. The parts of the apparatus are now again positioned as shown in FIGS. 5 and 6A so that the apparatus is ready for a further cycle of operation.

As an alternative to employing the shear blade as a stop for limiting the insertion of the connector into the sleeve, the working tip of the feed finger may be employed as the stop. In this case the shear blade is fixed relative to the ram and in the top dead center position of the ram, the shearing edge of the shear blade lies well above the strip of sleeves. The feed finger is arranged to assume its fully advanced position in the top dead center position of the ram so that a connector inserted into the leading sleeve engages the working tip of the feed finger, when fully inserted into the leading sleeve. The feed finger is retracted during the working stroke of the ram.

It will, therefore, be appreciated that the aforementioned and other desirable objects have been achieved; however, it should be emphasized that the particular embodiments of the invention, which are shown and described herein, are intended as merely illustrative and not as restrictive of the invention.

The invention is claimed in accordance with the following:

1. A method of applying insulating sleeves to electrical connectors comprising the steps of feeding a tube of plastic material into a cutting area, cutting said tube at predetermined lengths thereby forming a series of insulating sleeves connected together in an end-to-end strip, feeding the strip of insulating sleeves towards an applying station so that a sleeve at a time is placed at said applying station, inserting an electrical connector into a leading sleeve of said strip which is positioned at said applying station, securing the leading sleeve to the electrical connector, and shearing the leading sleeve from the strip adjacent said apply ing tation

Claims

1. A method of applying insulating sleeves to electrical connectors comprising the steps of feeding a tube of plastic material into a cutting area, cutting said tube at predetermined lengths thereby forming a series of insulating sleeves connected together in an end-to-end strip, feeding the strip of insulating sleeves towards an applying station so that a sleeve at a time is placed at said applying station, inserting an electrical connector into a leading sleeve of said strip which is positioned at said applying station, securing the leading sleeve to the electrical connector, and shearing the leading sleeve from the strip adjacent said applying station.