A DEVICE FOR STRIPPING INSULATED CABLES

Abstract: A device for stripping outer coatings from cables comprises a cutting edge movable so as to impinge on a portion of cable to be stripped. The portion of cable to be stripped is restrained by two surfaces adjacent the portion to facilitate the cutting of a section of the cable parallel to its longitudinal axis without damaging the inner element of the cable.

Description: A DEVICE FOR STRIPPING INSULATED CABLES This invention relates to a device for stripping the outer sheath from sheathed cables. While reference will be made to cables throughout, it is to be understood that this term is used deliberately to encompass sheathed cables of all kinds, including single core wires, multi-core wires, coaxial cables and fibre optic cables. The invention does, though, have particular application in the removal of the outer sheath from multi-core cable or flex confining separately insulated conducting wires. Various devices have been proposed for stripping electrical cables and wires, but generally these have been designed to expose an end length of conductor by cutting the sheath and drawing it axially from the end of the central component . Devices have also been proposed for stripping sheath from an intermediate length of electrical cable, but again the respective technique involved cutting the sheath in a plane generally transverse to the elongate direction of the conductor. The present invention is directed at a device which cuts an outer sheath or insulating layer from a cable in a plane generally parallel to the longitudinal direction of the cable, to directly expose the conductor or enclosed separate elements therebeneath. A device according to the invention comprises a seat with first and second walls which define an elongate recess for receiving a side of a portion of cable. At least one of the walls can be formed with a profiled or roughened surface, to assist in securing the cable in the recess. A cutting edge is movable over the face of the recess to one of the defining walls to cut a section of insulation or outer sheath from the exposed cable portion which projects laterally from the recess. The seat walls typically define a recess of V-shaped cross- section, although the cross-section can be adjustable in a number of respects. Normally though, adjustment of the recess is restricted to movement thereof towards or away from the path of movement of the cutting edge to accommodate cables of different overall cross-section. Nevertheless, there can be occasions when a more substantial alteration of the recess cross-section is appropriate; for example, to accommodate a flat cable rather than cable of generally circular cross section. Once set, the cross-section of the elongate recess in a device according to the invention is normally substantially uniform. However, the cross-section can vary in order to alter the profile of the sheath section removed by the cutting edge and also, if desired, to assist in holding in place the cable being cut. In a preferred embodiment of the invention, the recess is formed by first and second walls, the first defined by a base member, and the second by a seat member mounted on the base member. The second wall extends at an acute angle to the first wall and towards the path of movement of the cutting edge, and the seat member is movable relative to the base member to effectively shift the recess towards or away from the path of movement of the cutting edge. Adjustment of the device in all embodiments of the invention to shift the recess relative to the path of movement of the cutting edge that can be incremental or smooth, by means of a dial for example, but fixed incremental adjustment is normally preferred to accommodate cable of different standard sizes, of which there is a finite number. A range of recesses may be provided spaced circumferentially on the surface of a drum, which is itself rotatably mounted on the base member. In this arrangement, the drum can be rotated to align the desired recess with the path of movement of the cutting edge. A ratchet mechanism will normally be included to ensure proper alignment. The line of movement of the cutting edge over the face of the recess can be into abutment with the first wall. However, a preferred arrangement is one in which the first wall also forms a cutting edge with which the movable cutting edge makes a sliding, scissors-type, engagement. This enables full advantage to be taken of the flexibility and compatibility of the cable being stripped, while at the same time ensuring that a clean cut of the outer sheath from the cable is achieved. This preferred arrangement is one that is readily embodied in a construction in which the first and second walls are formed respectively on first and second jaws of a pivotal mechanism, the pivotal mounting of course defining the path of movement of the cutting edge . Nevertheless, and as will be apparent from the following description, this does not predetermine the alignment of the elongate recess and the cutting edge. They can be oriented substantially perpendicular or substantially parallel to the axis of the pivotal mounting. Embodiments of the invention will now be described by way of example and with reference to the accompanying schematic drawings, wherein: Figure 1 shows a perspective view of a device according to a first embodiment of the invention with a portion of cable disposed therein; Figures 2 and 3 show end views of the device of Figure 1 as the sheath of the cable portion is stripped; Figure 4 is a perspective view of a device according to a second embodiment of the invention; Figure 5 is a side elevation of the embodiment of Figure 4 ; Figure 6 is a detail view of a cable portion being stripped in a device according to the embodiment of Figures 4 and 5; and Figure 7 is a perspective view of a device according to a third embodiment of the invention. In the embodiment of the invention shown m Figure 1 a seat member 11 is mounted on a base member 12 at an acute angle to create an elongate recess therebetween. The seat member is formed with grooves 13 on its inner surface which serve to grip a portion 14 of cable to be stripped when it is pressed into the recess. A blade 15 formed with a cutting edge is guided by means not shown to move in a path over the face of the recess to cut the outer sleeve of the cable portion 14 therefrom, as shown m Figures 2 and 3. As is apparent from Figures 2 and 3 , the action of the blade 15 performs a purpose additional to that of cutting through the sheath of the cable portion 14. As it engages the cable portion, it distorts it into the recess and against the grooved surface of the seat member 11, while simultaneously drawing the sheath from individual conductors confined in the sleeve. Of course, to achieve this effect the recess must be adapted to accommodate cable of the appropriate size, and embodiments of the invention which include provision for adjustment of the recess are discussed below. The blade 15 in the embodiment of Figures 1 to 3 completes its movement when it abuts against the upper surface of the base member 12. At this stage, the stripping process is complete, as shown in Figure 3. As described in the embodiments discussed below, the base member 12 can be provided with a cutting edge through which the cutting edge of blade 15 can make sliding engagement to complete a scissors-like manoeuvre to strip the cable portion 14. The embodiment of the invention illustrated m Figures 4 to 6 takes the form of a tool for manual use which comprises a pair of pivotally interconnected jaws 20 and 22. Each jaw has a handle 24 biased away from the other by a spring 26, the tool as a whole being capable of holding m one hand, and operable in the manner described below. At the distal end of jaw 20 is formed a base member 28 upon which is mounted a seat member 30. The base member 28 defines a first wall 32 formed with three laterally spaced grooves 34. These are adapted to receive a leg 36 of the seat member 30, which is held there by a bolt 38 and hand- operated wing nut 58. The seat member defines the second grooved wall 40 which forms an acute angle with the first wall 32. Together they define the recess for receiving a portion of cable 44, as shown in Figure 6. The grooves serve to align and secure the cable 44 in the recess during use of the tool. At the distal end of the other jaw 22, a blade 46 is formed having a cutting edge 48. Pivotal movement of the jaws by squeezing the handles 24 moves the cutting edge along a path over the face of the recess formed between the first and second walls 32 and 40 to strip a section of the outer sheath 50 from the cable portion 44. The device shown in Figures 4 to 6 has the cutting edge 48 and the recess defined by the first and second walls 32 and 40 oriented substantially parallel to the pivotal mounting axis of the jaws 20 and 22. The cross section of the recess is illustrated as being generally uniform, but it will be appreciated that it could be made convergent along its elongate axis by altering the alignment of the grooves 34 parallel with the axis of the pivotal mount, or effectively by altering the orientation of the cutting edge 48 on the blade 46. As can be seen, in this embodiment the cutting edge 48 passes over a complementary edge 52 formed on the base member 28, m sliding engagement therewith. This arrangement, and the projecting complementary edge 52 serve to ensure that the cable sheath is cleanly cut. The embodiment of Figure 7 is broadly similar to that of Figures 4 to 6 , but the orientation of the cutting edge(ε) has been turned through 90° to the perpendicular with the pivotal axis of the jaw mount, generally extending along the longitudinal extent of one of the jaws 54. The components forming the recess are essentially the same, and the same reference numerals are used to identify them. However, the cutting edge is of course formed directly on the edge of the lower jaw 54, and the cutting edge 48 formed directly on the edge of the upper jaw 56. The cutting edge 48 makes sliding engagement with the complementary edge of the lower jaw 54 in a scissors-type movement to cut the outer sheath from cable held in the recess. As the scissors movement of the jaws generates a force that would otherwise drive the cable away from the pivotal axis of the jaws, some form of restraint can be incorporated in the device. For example, the cross section of the recess at the end near the pivotal axis can be made smaller than at the other end so that the cable is held in the recess as the sheath is cut. Alternatively, some longitudinal gripping mechanism can be incorporated in the recess. Indeed, some quite separate mechanism can be used to restrain the cable which could of course merely be held by the user as he grips the handle 24.

Claims: CLAIMS : 1. A device for stripping the outer sheath from sheathed cables, comprising a seat with first and second walls defining an elongate recess for receiving a side of such cable, and a movable cutting edge w th means for directing its movement over the face of the recess to the first wall to cut a section of outer sheath from cable received therein. 2. A device according to Claim 1, wherein the seat walls define a recess of V-shaped cross-section. 3. A device according to Claim 1 or Claim 2, wherein the cross-section of the recess is substantially uniform. 4. A device according to Claim 1 or Claim 2, wherein the cross-section of the recess reduces along its length. 5. A device according to any preceding claim, wherein at least one of the walls has a profile or roughened surface to assist in securing cable in the recess . 6. A device according to any preceding claim, wherein the cross-section of the recess is adjustable. 7. A device according to Claim 6, wherein the depth of the recess is adjustable relative to the path of movement of the cutting edge. 8. A device according to Claim 7 including means for incremental adjustment of the depth of the recess relative to the path of movement of the cutting edge. 9. A device according to Claim 6 or Claim 7 comprising a base member defining the first wall and a seat member mounted on the base member and defining the second wall inclined at an acute angle to the first wall, and towards the path of movement of the cutting edge, the seat member being movable relative to the base member between positions at different spacings from the path of movement of the cutting edge. 10. A device according to any preceding claim, wherein the path of movement of the cutting edge is spaced from the face of the recess. 11. A device according to any preceding claim, wherein the path of movement of the cutting edge is into abutment with the first wall. 12. A device according to any of Claims 1 to 10, wherein the path of movement of the cutting edge is past an edge formed on the first wall, the two edges making sliding engagement in such movement . 13. A device according to any preceding claim, wherein the first wall is formed on a first jaw and the cutting edge is formed on a second jaw, the second jaw being pivotally mounted on the first jaw, which mounting defines the path of movement of the cutting edge. 14. A device according to Claim 13, wherein the elongate recess extends substantially perpendicular to the axis of the pivotal mounting. 15. A device according to Claim 13, wherein the elongate axis of the recess extends substantially parallel to the axis of the pivotal mounting. 16. A device for stripping the outer sheath from sheathed cable substantially as described herein with reference to Figures 1 to 3 ; Figures 4 to 6 ; or Figures 7 to 9 of the accompanying drawings . 17. A method of stripping the outer sheath from sheathed cable, comprising laying a portion of the cable between walls of a seat defining an elongate recess with a section thereof projecting from the face of the recess, and directing a cutting edge over the face of the recess to cut the outer sheath from the projecting section while simultaneously pressing the remainder of the cable portion into the recess. 18. A method according to Claim 15, including the step of setting the cross-section of the recess and its spacing from the path of movement of the cutting edge to match the cable being stripped. 19. A method of stripping the outer sheath from sheathed cable substantially as described herein with reference to the accompanying drawings.

Inventors: CACKETT DENNIS WILLIAM, CACKETT, DENNIS, WILLIAM
Applicants: CACKETT DENNIS WILLIAM, CACKETT, DENNIS, WILLIAM
Application year: 1997
Main classification: H02G1
IPC codes: H02G1