US3541896A

US3541896A - Apparatus for stripping cables

Info

Publication number: US3541896A
Application number: US739673A
Authority: US
Inventors: Richard J Watson
Original assignee: Western Electric Co Inc
Current assignee: AT&T Corp
Priority date: 1968-06-25
Filing date: 1968-06-25
Publication date: 1970-11-24
Anticipated expiration: 1987-11-24

Description

av. 24', 1970 R. J. WATSON APPARATUS FOR STRIPPING CABLES Filed Jun 25, 1968 A s Sheets-Sheet 1 ZNvEA/T Q Nov. 24, 1970 R. J. WATSON 35,541,896

APPARATUS FOR STRIPPING CABLES Filed June 25, 1968 3 sheets-sheet 2 Nov. 24, 1970 R. J. WATSON 3,541,896

APPARATUS FOR STRIPPING CABLES 7 Filed June 25', 1 968 s Sheets-Sheet :5

United States Patent 3,541,896 APPARATUS FOR STRIPPING CABLES Richard J. Watson, Danvers, Mass., assignor to Western Electric Company, Incorporated, New York, N.Y., a corporation of New York Filed June 25, 1968, Ser. No. 739,673

Int. Cl. H02g l/12 U.S. Cl. 819.51 14 Claims ABSTRACT OF THE DISCLOSURE A cable Stripping apparatus includes a rotating head with first and second pivotally mounted cutters. A yoke is moved axially in the head. A first cam on the yoke pivots the first cutter to cut through a braided cable shielding. The shielding disintegrates and exposes a plastic insulation. A second cam on the yoke then pivots the second cutter, moving a bifurcated cutting blade on the second cutter to cut through an axially offset portion of the insulation. The second cutter is next moved axially. The bifurcated cutting blade strips the severed insulation axially off of a central conductor core.

BACKGROUND OF THE INVENTION This invention relates to apparatus for stripping coverings off of core members and, more particularly, to apparatus for removing sections of an outer and an inner covering from a central cable conductor.

In the art of stripping outer and inner coverings off of articles, such as conventional coaxial cables, it is desirable that simple and reliable, yet effective, semiautomatic and automatic mechanisms be provided for quickly and easily removing the coverings from a central core member, such as a central conductor core. Such mechanisms obviate the need for time consuming, manual stripping operations, using hand tools.

Additionally, it is frequently desired that the outer and inner coverings be stripped from the central core at different points along their respective lengths. In this manner, axially extending sections of both the inner covering and the central core may be exposed. The outer covering, moreover, may be formed of braided wires of copper or other material, acting as a shielding for the central conductor core. The relatively hard nature of such covering will tend to cause injury or excessive Wear to a cutting blade designed to cut through and strip off a softer inner covering, such as a plastic or other insulation. Both of these factors much be taken into account in the design of the apparatus.

SUMMARY OF THE INVENTION An object of the invention resides in new and improved apparatus for stripping coverings off of core members, such as by removing sections of outer and inner coverings from a central conductor core of a cable or similar article.

The invention contemplates the provision of a rotatable cutter head assembly having an axially extending opening into which one end of a cable is inserted, for example, manually. A pair of cutters or cutter arms are pivoted successively into contact with the cable so that a first blade may sever and disintegrate a braided outer covering and then a second blade may sever an exposed inner covering surrounding a central core member of the cable.

The invention further contemplates the use of a mechanism for displacing the second blade axially to strip the severed section of the inner covering axially off of the central core, the second blade preferably being bifurcated to aid in this stripping operation.

ice

The invention further contemplates the locating of the first and second blades on the cutters or cutter arms in such positions that the outer and inner coverings are severed at axially spaced locations along the length of the cable.

BRIEF DESCRIPTION OF THE DRAWING FIGS. 1 through 5 are side elevational views of portions of a rotating cutter head assembly constructed in accordance with the principles of the invention, illustrating successive stages in the operation of various elements of the head during the stripping of a pair of concentric coverings off of a central conductor core of a coaxial cable;

FIG. 6 is an exploded isometric view of a major portion of the cutter head assembly showing additional elements thereof;

FIGS. 7 and 8 are fluid circuit diagrams illustrating successive stages in an operating and control system which may be utilized with the cutter head assembly of the FIGS. 1-6; and

FIG. 9 is a side elevational view of a portion of a co axial cable showing the cable after the stripping of sections of braided outer covering and an inner covering off of a central conductor core by means of the apparatus of FIGS. 1-8.

DETAILED DESCRIPTION Turning first to FIG. 9 of the drawing, a coaxial cable 11 includes an axially extending central conductor core 12 surrounded by a layer of plastic or other insulation 13, for example, a plastic sold under the trade name Teflon. The insulation covering 13 is, in turn, surrounded by an outer shielding member, such as covering of braided copper wires 14. It is desired that the cable 11 be stripped to expose an axially extending portion 12 of the central conductor core 12 and an axially extending portion 13' of the inner covering of insulation 13, as is shown in FIG. 9.

Referring next to FIGS. 1-6, an apparatus for stripping an article, such as the coaxial cable 11, to provide the configuration of FIG. 9 includes a cutter head assembly 16 which is mounted to rotate with rotation of an axially movable shaft 17. The cutter head assembly 16 comprises all elements depicted in FIGS. 16 with the exception of the cable 11 and a chuck 33. Suitable bearings (not shown) mount the shaft 17 for both rotation and axial movement. Included in the cutter head are a pair of pivotally mounted

cutter arms

18 and 19 and a yoke 21. The yoke 21 is fixed to the shaft 17 by a dowel pin 20. The

cutter arms

18 and 19 are secured to

pivot pins

22 and 23, respectively. The pivot pins extend through a pair of mounting holes in each of a pair of plates 24 and 25 (FIG. 6) which are rotatable with rotation of the shaft 17. Two sets of counterbalance members 26 and 27 (only one of which sets is shown in FIG. 6) are carried on opposite ends of the

pivot pins

22 and 23 to counterbalance the pivotally

movable cutter arms

18 and 19, respectively, during rotation of the cutter head assembly 16. A pair of

cutter blades

28 and 29 are carried by the pivotally mounted

cutter arms

18 and 19, respectively. Each blade extends at a right angle to a major portion of the

respective cutter arm

18 or 19. The two

blades

28 and 29 extend facing generally toward one another, being slightly axially offset from one another, at opposite sides of a central axis of the cutter head assembly 16. The cutter head assembly includes an axially extending opening 31 (FIGS. 1 and 5) into which a coaxial cable 11 may be thrust axially, for example, manually. A stop 32 extends into the opening 31 to locate accurately an end of the cable 11. The stop may be mounted on the plate 24 (FIG. 6) for adjustable movement, for example, ax-

ially. A chuck 33 is located to grip the cable 11, holding the cable axially against the stop 32 during the stripping operation to be performed by the cutter head assembly.

Each of the pivotally mounted

cutter arms

18 and 19 has a

cam follower surface

36 or 37 located along a portion thereof facing away from the central axis of the cutter head assembly 16. The yoke 21 has a pair of

camming projections

38 and 39 located along opposing portions thereof facing toward the central axis of the assembly. The camming projection 38 will contact the cam follower surface 36 on the cutter arm 18 as the yoke 21 is moved axially to the left (as seen in FIG. 2). The camming projection 39 will then contact the cam follower surface 37 on the cutter arm 19 as the yoke 21 is moved further to the left (FIG. 3).

As may be seen in FIGS. 1-3, this arrangement will cause first the blade 28 and thereafter the blade 29 to pivot into cutting engagement with the coaxial cable 11. The first blade 28 will cut through the braided outer covering 14 (FIG. 9) as the cutter head assembly 16 is rotated about its axis and, therefore, the pivoted cutter arm 18 orbits the cable 11. The severing of the braided covering 14 will cause the braided covering to disintegrate as the blade 28 sweeps about an outer surface of the inner covering 13. A blow pipe 40 (FIGS. 7 and 8) may be positioned adjacent the cutter head assembly to direct pressurized air at the severed braiding so as to aid in causing the braiding to disintegrate. Once the braiding has been removed, a bifurcated portion 41 (FIG. 6) of the second blade 29 will contact the relatively soft inner layer of insulation 13 (FIG. 9), severing the insulation as the blade 29 orbits the central conductor core 12. The second blade 29 is offset axially by a slight amount from the first blade 28, as may be seen in FIGS. l-6, in order to produce the configuration shown in FIG. 9 which requires axially spaced cuts for the two different layers 13 and 14. The axial offset between the

blades

28 and 29 will result in the formation of the exposed, axially extending, central conductor core and insulation portions 12' and 13', respectively. The

cutter blades

28 and 29 may be simply removed and replaced in the cutter head assembly by removal of four dowels 42 which retain the blades in receiving portions of the

respective cutter arms

18 and 19. This will enable an operator to substitute different cutter arms 18 and/or 19 for those shown. The relative degree of axial olfset between the

blades

28 and 29, and, therefore, the lengths of the exposed portions 12' and 13' may be easily and quickly readjusted to suit new requirements. The offset may, of course, be reduced to zero to expose an axially extending portion 12' of the central conductor core 12 only, if such is desired.

The plates 24 and 25 (FIG. 6) are secured to a generally U-shaped guide member 43. The crosspiece 44 and the

legs

46 and 47 of this guide member bound a channel 48 aligned with the axially extending opening 31 (FIGS. 1 and for receiving the cable 11. The channel 48 constitutes a guideway for the above-described axial movement of the yoke 21. A guiding function is also performed by the dowel pin associated with the yoke 21, thedowel pin following slots 51 (FIG. 6) in the

plates

24 and 25, as well as by the plates 24 and themselves. A pair of coil springs 53, 53 (FIGS. 1-5), having first ends thereof held against an axially fixed bearing 54, have their second ends bearing against the cross-piece 44 to bias the guide member 43 toward the right (as seen in FIGS. 1-3). Thus, the guide member 43 is held in a normal rest position during the initial axial movement of the loke 21 which causes the cutting operations of the cutter blades 28 and 29 (FIGS. 1-3). However, once the yoke 21 has been moved axially, sufficiently far to engage the cross-piece 44 of the guide member, which circumstance will occur after the second blade 29 has cut completely through the inner covering 13 (FIG. 3), continued axial displacement of the yoke 21 will move the guide member 43 to the left (as seen in FIG.

4). As stated above, the cutter arm 19 is secured to the pivot pin 23, which is pivotally mounted on the

plates

24 and 25. The

plates

24 and 25 move axially with the guide member 43. Thus, the bifurcated portion 41 of the second blade 29 will strip the severed section of the inner covering 13 axially ofi of the central conductor core 12 of the cable 11 as the second cutter 19 moves axially to the left.

The operation of the apparatus will next be described, with further reference to FIGS. 7 and 8 of the drawing, wherein an exemplary fluid circuit for operating and controlling the cutter head assembly 16 in the manner described above is illustrated. The operating medium is preferably a pressurized fluid, typically compressed air, as described hereinafter. Alternatively, however, a fluid at subatmospheric pressure may be utilized with a suitably modified fluid circuit or an analogous electrical control circuit may be substituted in a manner obvious to a person having ordinary skill in the art.

An air compressor or pump 56 is connected both to the blow pipe 40 and to a main control valve 57. The two operating positions of the valve 57 are shown in FIGS. 7 and 8, respectively. FIG. 7 shows the condition of the fluid circuit during axial loading of the coaxial cable 11 between the jaws of the initially-open chuck 33 (see also FIG. 5) and against the stop 32 in the opening 31 of the cutter head assembly 16. FIG. 8 shows the condition the fluid circuit will assume after the coaxial cable has been correctly positioned in the opening 31 for cutting and stripping by the cutter head assembly. The main control valve 57 may be operated manually or may be actuated by any known mechanism for signalling the correct positioning of the coaxial cable against the stop 32, for example, a solenoid energized upon the closing of a suitably positioned limit switch.

In the initial, loading condition of the circuit shown in FIG. 7, pressurized air is communicated by the main control valve 57 from the compressor 56 to a first (right) end of a main cylinder 58 which contains a piston (not shown). A piston rod 59 controls the axial positioning both of the shaft 17 for moving the yoke 21 axially and of a reversing valve 61. The reversing valve 61 is initially positioned to communicate pressurized air from the compressor 56 to a first (lower) end of a chuck control cylinder 62 so as to hold open the jaws of the chuck 33. The main control valve 57, when in the loading position (FIG. 7), also communicates with exhaust the opposite second ends of the

cylinders

58 and 62, as well as the conventional, fluid-operated mechanism for engaging a clutch 63. The clutch 63, when engaged by communication with pressurized air from the compressor 56, will connect the shaft 17 to rotate with a rotary drive shaft (not shown).

The coaxial cable 11 is now loaded, for example, manually, such that the cable extends between the open jaws of the chuck 33 (FIG. 5), while one end of the cable contacts the stop 32, as shown in FIG. 1. The main control valve 57 is then moved, for example, manually by means of a handle 64, into the position shown in FIG. 8. As a result, pressurized air is applied to the second ends of both the main cylinder 58 and the chuck control cylinder 62, as well as to the clutch 63. At the same time, the first (right) end of the main cylinder 58 is communicated to exhaust. Thus, the piston rod 59, extending from the main cylinder '58, begins to move to the right (as seen in FIG. 8). A cam 66 and a spring 67 cooperate, upon an initial rightward movement of the piston rod 59, to reposition the reversing valve 61 into the FIG. 8 position of this valve. The first (bottom) end of the chuck control cylinder 62 is communicated to exhaust upon this movement of the reversing valve 61. Thus, the jaws of the chuck 33 close about the coaxial cable 11, gripping the cable to hold it firmly in place driving the subsequent cutting and stripping operations. This is the condition of the apparatus shown in FIG. 1.

The main control valve 57 also functions to cause engagement of the clutch 63 for rotating the shaft 17 so as to rotate the entire cutter head assembly 16. A flow control valve 68 is positioned in a line 69 leading to the clutch 63. The flow control valve 68 is preferably adjusted to cause engagement of the clutch 63, initiating rotation of the shaft 17 (FIG. 1), after the chuck control cylinder.62 has closed the jaws of the chuck 33 about the coaxial cable 11 to grip the cable therebetween.

As the piston rod 59 moves to the right (as seen in FIG. 8), a rocker arm 71 and collet 72 cooperate to displace the rotating, axially movable shaft 17 and the associated yoke 21 to the left (as seen in FIG. 8 and in FIGS. 1-4). 'Suflicient leftward movement of the yoke 21 to pivot the first cutter arm 18 into cutting engagement with the outer layer of braided shielding 14 is to occur only after (1) the chuck 33 has firmly gripped the cable 11 and (2) the clutch 63 has been engaged to start rotation of the shaft 17 and, therefore, the cutter head assembly 16. A flow control valve 73 in a line 74 leading into the second (left) end of the main cylinder 58 may be adjusted to control the rate of displacement of the piston rod 59 and, therefore, of the axially movable shaft 17.

As the shaft 17 and the yoke 21 are displaced to the left (as seen in FIG. .2), the first cutter arm 18 is pivoted by the camming action of the first camming projection 38 against the cam surface 36. Thus, the first cutting blade 28 engages the braided outer covering 14. The blade 28 orbits the inner covering 13, severing the braided covering 14 which disintegrates as the blade 28 moves. The disintegration of the braid is aided by the influence of the stream of pressurized air issuing from the blow pipe 40 (FIG. 8).

Continued movement of the yoke 21 to the left (as seen in FIG. 3) causes the bifurcated portion 41 (FIG. 6) of the second cutter blade 29 to engage an axially offset portion of the exposed, relatively soft inner covering 13. The insulation covering 13 is now severed without any significant wear or damage to the bifurcated portion of the blade.

Further leftward movement of the yoke 21 (as seen in FIG. 4) will drive the guide member 43 to the left, moving the

plates

24 and 25 and the

cutter arms

18 and 19 also to the left. Movement of the bifurcated portion 41 of the second cutting blade 29 to the left will strip the severed section of the inner covering 13 axially off of the central conductor core 12 of the coaxial cable 11. As set forth above, the cable is retained against axial movement during the stripping action of the blade 29 by means of the chuck 33.

The resultant configuration of the stripped coaxial cable 11 is depicted in FIG. 9. It should be noted, once again, that the section of the inner covering 13' cut and stripped by the second cutter blade 29, exposing the conductor core at 12, is offset axially from the section of the outer covering 14 cut by the first cutter blade 28, exposing the insulation at 13', due to the axial offseting of the two blades as described above. Additionally, it should be clear that the braided copper wires of the outer covering 14 will not have caused any damage or excessive ware to the bifurcated portion 41 of the second cutting blade 29, all contact between the covering 14 and the blade 29 having been avoided.

The main control valve 57 may now be returned to the position shown in FIG. 7, for example, due to the bias of a return spring (not shown) effective upon release of the handle 64. The fluid circuit, thus, reassumes the initial loading condition of FIG. 7, while the cutter head assembly 16 returns to the operating position shown in FIG. 1. The stripped coaxial cable 11 may now be removed from between the opened jaws (still as in FIG. of the chuck 33 and the apparatus may be used in stripping additional sections of cable.

It is to be understood that the above described apparatus is simply illustrative of one embodiment of the invention. Many modifications may be made without departing from the invention.

I claim:

1. In a severing device for making successive cuts in a held article;

a pair of cutter means separately mounted for pivotal movement into engagement with said article and for rotary movement about said article;

means for rotating said cutter means about the article; and

means operable while the cutter means are rotating for successively pivoting a first of said cutter means into severing engagement with said article, and then for pivoting the other of said cutter means into servering engagement with said article to make a cut at a depth greater than the cut depth of said first cutter means.

2. In a severing device as defined in claim 1, wherein the pair of cutter means include a pair of cutter blades which are axially spaced from each other along the axis of rotation of said cutter means about the article.

3. In a severing device as defined in claim 1, wherein one of said cutter means is mounted for axial movement to strip a cut portion axially off of said article and includes a bifurcated blade for stripping the cut portion.

4. In a cutting device for cutting different sections of an article;

a pair of cutters mounted for pivotal movement toward an article positioned between the cutters, said cutters having blades offset from each other to engage dilferent sections of the article;

means for imparting relative rotational movement between said article and said cutters; and

means operated during said relative rotation for pivoting a first of said cutters to move its blade into engagement with said article to make a cut at a first depth and then pivoting the second cutter to move its blade into engagement with said article to make a cut at a second depth greater than said first depth.

5. In a cutting device as defined in claim 4;

means mounting the second cutter for movement along the axis of relative rotation between said article and said cutters; and

means operative while the second cutter is in engagement with the article for axially moving said second cutter.

6. In a device for stripping a cable comprising a pair of concentric coverings on a core wire;

a head having an axial opening therein;

a pair of oppositely disposed cutter arms pivotally mounted in the head and extending into said opening, each of said cutter arms including a blade;

means for positioning an end section of a cable within said opening to position the coverings in alignment with said blades;

trneans for rotating said head relative to said cable to rotate said blades about said cable; and

means for sequentially pivoting a first of said cutter arms to move a first blade to penetrate and sever a first covering, and then pivoting the second of said cutter arms to move the second blade to penetrate and sever the second covering.

7. In a device as set forth in claim 6;

means rendered effective following pivoting of the second cutter arm for moving said second cutter arm axially of said head to strip the second covering from the core wire.

8. In a device as set forth in claim 6;

said blades on said cutter arms being offset axially one from the other in position to sever axially spaced sections of the first and second coverings.

9. In apparatus for stripping a pair of concentric coverings off of an axially extending core, the outer covering of the pair having a braided configuration;

a rotatable head having an axially extending opening for housing the covered core;

7 a pair of cutters mounted in said head to pivot into cutting engagement with the concentric coverings of the core in said opening; means for rotating said head to orbit said cutters about the covered core; means for pivoting a first of said pair of cutters into cutting engagement with the braided outer covering to sever and disintegrate the braided covering with rotation of said head, whereby an inner covering of the pair of concentric coverings is exposed; and means operated subsequent to pivoting said first pair of cutters for pivoting the second pair of cutters into cutting engagement with the exposed inner covering to sever the inner covering. 10. In apparatus for stripping a pair of coverings off of a core, as set forth in claim 9;

said first cutter including a pivotally mounted arm carrying a first blade positioned to engage a first location on the outer covering during rotation of said head for severing and disintegrating the outer covering; and said second cutter including a pivotally mounted arm carrying a second blade positioned to engage a second location on the exposed inner covering during continued rotation of said head with the outer covering disintegrated, said second location on the inner covering being offset axially from said first location on the outer covering. 11. In apparatus for stripping a pair of coverings off of a core, as set forth in claim 9;

means rendered effective upon said second cutter pivoting to sever the exposed inner covering for moving said second cutter axially along the core to strip the severed inner covering off of the core. 12. In apparatus for stripping a pair of coverings off of a core, as set forth in claim 11;

said second cutter including a pivotally mounted arm carrying a bifurcated cutter blade having a recess between the bifurcations positioned to engage the inner covering and strip the inner covering off of 8 v l the core upon axial movement of said second cutter.

13. In apparatus for stripping a pair of coverings 01f of a core, as set forth in claim 9, said first and second pivoting means comprising:

a first cam follower surface located on said first cutter;

a second cam follower surface located on said second cutter;

a yoke mounted for axial movement in said head;

a first camming projection mounted on said yoke in position to engage said first cam follower surface and pivot said first cutter into cutting engagement with the outer braided covering upon axial movement of said yoke;

a second camming projection mounted on said yoke in position to engage said second cam follower surface and pivot said second cutter into cutting engagement with the exposed inner covering upon further axial movement of said yoke; and

means for moving said yoke axially of the covered core.

14. In apparatus for stripping a pair of coverings off of a core, as set forth in claim 13;

means mounting said second cutter in said head and positioned to be engaged by said yoke upon continued axial movement of said yoke after pivoting of said second cutter into cutting engagement with the exposed inner covering for moving said second cutter axially with continuing axial movement of said yoke to strip the severed inner covering off of the core.

References Cited UNITED STATES PATENTS 2,526,955 10/1950 Kugler 30-94 2,695,537 11/1954 Imman et al. 3091.2 3,222,957 12/1965 Kramer et al. 819.51 3,309,768 3/1967 Thompson 309l.1

ROBERT C. RIORDON, Primary Examiner 40 R. V. PARKER, JR., Primary Examiner