CABLE STRIPPING DEVICE

Abstract: The invention relates to a device for stripping an insula­ tion sheath from an end portion of a cable. The device comprises two manually graspable handles (10, 11) which are capable of relative movement towards and away from one another, a pair of jaws (14, 17) which move towards one another during a first, rotary, part of relative movement of the handles towards each other to grip a cable (C) placed in use between said jaws and a pair of cutter blades (24) disposed adjacent to the jaws and which move towards one another during said first, rotary, part of the handle move­ ment thereby to cut through an outer insulating sheath of said cable, the cutter blades (24) during a second, rec­ tilinear, part of said relative movement of the handles (10, 11), moving away from the jaws (14, 17) to strip the outer sheath from the cable. It has been found particularly advantageous that the second part of the movement is approximately parallel in direction to the longitudinal center line of the cutter blades.

Description: This invention relates to a device for stripping an outer insulating sheath from an electrical cable to reveal an inner conducting core. Such a device will henceforth be referred to as a cable stripping device. US Patent No 2601797 discloses a cable stripping device comprising a pair of manually operable handles by means of which a pair of jaws and a pair of cutters are first pivoted to grip and cut through the insulating sheath, the cutters then being withdrawn rectilinearly from the jaws to remove the severed end of the sheath. Operation of the device is by means of a relatively complex series of linkages. Another construction of this general type in which movement of the cutters relative to the jaws is by means of a slidable mounting of one handle relative to the other is shown in US Patent No 3125908. In this case, however, the device is of even more complex construction. According to the present invention, there is provided a cable stripping device comprising first and second manually graspable handles which are capable of relative movement towards and away from one another, first and second jaws which move towards one another during a first, rotary part of relative movement of the handles towards each other to grip a cable placed in use between said jaws, the first jaw and the first handle together forming a first lever member, and the second jaw forming part of a second lever member which is pivotally connected at a stationary point to the first lever member, and a pair of cutter blades disposed adjacent the jaws and which are urged together by the movement of the first and second lever members during said first, rotary part of the handle movement thereby to cut through an outer insulating sheath of said cable, the cutter blades during a second, rectilinear part of said relative movement of the handles, moving away from the jaws to strip the outer sheath from the cable, characterised in that the second handle is slidably mounted on the second lever member and carries the cutter blades, such that during the second, rectilinear part of said handle movement the second lever member remains stationary relative to the first lever member and the second handle slides rectilinearly relative to the second lever member so as to draw the cutter blades away from the jaws. Conveniently, the cutter blades are formed respectively on the ends of a resiliently deformable U-shaped member which is disposed between the first and second lever members. It has been found particularly advantageous to the operation of the device if the direction of the second, rectilinear movement between the handles is parallel or substantially parallel to the longitudinal centre line of the member carrying the pair of cutter blades. Desirably, the device also includes a cable cutter which is operated by means of said handles. The cable cutter may comprise an anvil formed on the first lever member and a cutter blade mounted on the second handle or on the second lever member so as to be movable towards and away from the anvil. The anvil is preferably formed by a side wall of a laterally extending hole in the first lever member. Conveniently, the device also includes a cutter for separating the cables of a twin cable (eg a lamp flex), which cutter is also operated by means of said handles. As with the above-mentioned cable cutter, this cutter can comprise an anvil formed on the first lever member and a cutting blade mounted on the second handle or on the second lever member so as to be movable towards and away from the anvil. The anvil is preferably formed by a side wall of a bore in the first lever member. Most advantageously, the cutting blade of the cutter also constitutes the cutting blade of the cable cutter, and the bore and the hole in the first lever member intercommunicate. Desirably, movement of the cutter blades towards the jaws is limited by a stop between the second handle and the second lever member, and a spring urges the second handle towards the stop and thereby also urges the first and second levers apart. Preferably, the handles are disposed closely adjacent to one another so that they can be manually squeezed together, and one handle is recessed to receive the other handle during such squeezing movement. The invention will now be described, by way of example only, with reference to the accompanying drawings, in which:- Figure 1 is a side view of a cable stripping device according to the present invention, shown in a starting position; Figures 2 and 3 are scrap side views of the device in various positions during a cable stripping operation; Figure 4 is a section on the line IV-IV in Figure 1; and Figure 5 is a view in the direction of arrow V in Figure 1. Referring first to Figure 1, the illustrated cable stripping device is composed generally of a pair of handles 10 and 11 which can be manually squeezed together against the action of a spring 12, the handle 10 being recessed to allow the handle 11 to be received therein during such squeezing movement. The handle 10 forms one limb of a first lever member 13 of generally L-shaped configuration, the other limb 13 a thereof having a jaw element 14 formed at its free end. A second lever member 15 is mounted on the first lever member 13 for pivotal movement relative thereto about an axis 16, and has a jaw element 17 formed at its free end which confronts the jaw element 14. As can be seen to advantage in Figure 4, the lever member 15 is generally of inverted U-shaped cross-section and has a rebated recess 18 extending along its base. The handle 11 has a T-shaped projection 19 at its upper end which engages in the recess 18 to enable the handle 11 to slide rectilinearly relative to the lever members 13. The projection 19 extends somewhat forwardly of the handle 11 itself and is urged by the spring 12 into contact with a stop 20 adjacent to the jaw element 17, causing the handle 11 normally to occupy the position illustrated in Figure 1 wherein the pivot axis 16 passes therethrough. As also illustrated in Figure 1, pivotal movement of the lever member 15 relative to the member 13 under the influence of the spring is limited by a pair of stops 21 and 22 provided on these members, respectively. Disposed between the lever members 13 and 15 is a generally U-shaped resilient member 23 having a pair of cutting blades 24 formed at its ends, respectively, these blades normally being positioned closely behind the jaw elements 14 and 17. A slot (not visible in the drawings) is provided in a central portion of the member 23 so that the latter can straddle an upper part of the handle 11 and pass around lugs 25 (only one visible) provided thereon. An upper limb of the member 23 bears against the underside of the extended projection 19 on the handle 11, while a lower limb of the member 23 bears against an upper surface of the limb 13 a of the lever member 13. In order to strip the outer insulating sheath from an electrical cable, the cable,C (Figure 3), is placed between the jaw elements 14 and 17 and the handles 10,11 are then manually squeezed. Because of the geometry of the arrangement, during a first part of the squeezing movement the handle 11 and the lever member 15 remain locked together under the force of the spring 12 so that they pivot in unison relative to the lever member 13. This causes the jaw elements 14 and 17 to grip the cable and at the same time causes the cutting blades 24 to cut into the insulating sheath. Under this condition (as depicted in Figure 2), the lever member 15 can pivot no further and therefore effectively becomes solid with the lever member 13. Therefore, continued squeezing of the handles causes the handle 11 to slide rectilinearly relative to the lever member 15 against the action of the spring 12 (see Figure 3), thereby withdrawing the cutting blades 24 from the jaw elements 14, 17 and causing the blades to strip the insulating sheath from the cable. In the illustrated embodiment, it is found that upon release of the handles 10 and 11 the jaw elements 14 and 17 separate to release the cable before the cutting blades 24 have returned to their starting position, thereby avoiding damage to the cut end of the sheath by this return movement of the blades 24. This is thought to result from the frictional resistance to the sliding movement of the projection 19 along the recess 18 combined with the way in which the spring 12 applies a returning force to the various components. Thus, it is not necessary to provide a separate latch mechanism for preventing return of the cutting blades 24 until the jaw elements 14 and 17 have separated, which means that the present device can be made with fewer component parts and therefore at a lower cost. However, this is not to say that such a latch mechanism could not be provided as a safeguard measure, if desired. In the illustrated embodiment, the cable stripping device is provided with certain accessories to further assist the preparation of an electrical cable for connection to a plug, appliance or the like. A first of these accessories is a cable cutter and is formed by a cutting blade 26 mounted on the handle 11 and an anvil provided by the side wall of a through hole 27 formed in the limb 13 a of the lever member 13. A cable can therefore be cut simply by passing it through the hole 27 and squeezing the handles 10 and 11, thereby causing the cutting blade 26 to move against the anvil. A second accessory is a cutter for separating the cables of twin cable (i.e. two cables integrally joined by means of their insulating sheaths). This cutter also utilises the cutting blade 26, but this time in conjunction with a bore 28 which enters the limb 13 a from just below the jaw element 14 and which opens into the through hole 27. As can be seen to advantage in Figure 5, the bore 28 is so shaped that the division between the cables automatically becomes aligned with the cutting blade 26 when the twin cable is inserted into the bore, so that the cables can then be separated simply by squeezing the handles 10 and 11 together. Although not specifically illustrated, a further accessory may be provided which enables the insulating sheath of a cable to be slit longitudinally, whereby the cut parts of the sheath may be parted to reveal the underlying conductor or conductors. This accessory is advantageously provided by means of a channel formed in the free end of the limb 13 a of the member 13 at a position just below the bore 28, into which the cutting blade 26 can be partially extended by squeezing the handles 10 and 11 together as aforesaid. The cable can thus be inserted into the channel and drawn lengthwise therethrough, such that the projecting part of the blade 26 produces the required slit in the sheath. It is preferred that the major components of the device (i.e. the lever members 13, 15 and the handle 11) are moulded from a suitable plastics material, with the member 23 and the cutting blade 26 being made of metal and being secured to the plastics components by any convenient method, such as by riveting.

Claims: A cable stripping device comprising first and second manually graspable handles (10,11) which are capable of relative movement towards and away from one another, first and second jaws (14,17) which move towards one another during a first, rotary part of relative movement of the handles (10,11) towards each other to grip a cable placed in use between said jaws (14,17), the first jaw (14) and the first handle (10) together forming a first lever member (13), and the second jaw (17) forming part of a second lever member (15) which is pivotally connected at a stationary point to the first lever member (13), and a pair of cutter blades (24) disposed adjacent the jaws (14,17) and which are urged together by the movement of the first and second lever members (13,15) during said first, rotary part of the handle movement thereby to cut through an outer insulating sheath of said cable, the cutter blades (24) during a second, rectilinear part of said relative movement of the handles (10,11), moving away from the jaws (14,17) to strip the outer sheath from the cable, characterised in that the second handle (11) is slidably mounted on the second lever member (15) and carries the cutter blades (24), such that during the second, rectilinear part of said handle movement the second lever member (15) remains stationary relative to the first lever member (13) and the second handle (11) slides rectilinearly relative to the second lever member (15) so as to draw the cutter blades (24) away from the jaws (14,17). A cable stripping device as claimed in claim 1, wherein the direction of the second, rectilinear part of said movement is at least substantially parallel to the longitudinal centre line of the pair of cutter blades (24). A cable stripping device as claimed in claim 1 or claim 2, wherein the cutter blades (24) are formed respectively on the ends of a resiliently deformable U-shaped member (23) which is disposed between the first and second lever members (13,15). A cable stripping device as claimed in any preceding claim, wherein a stop (20) is provided between the second handle (11) and the second lever member (15) to limit movement of the cutter blades (24) towards the jaws (14,17), there being further provided a spring (12) to urge the second handle (11) towards the stop (20) and thereby also to bias the first and second lever members (13,15) apart. A cable stripping device as claimed in any preceding claim, wherein there is further provided a cable severing means comprising a cable cutter (26) having an anvil (27) formed on the first lever member so as to be movable towards and away from the anvil (27). A cable stripping device as claimed in any preceding claim, wherein the handles (10,11) are disposed closely adjacent to one another, one handle (10) being recessed to receive the other handle (11) during a manual squeezing movement.

Inventors: HEPWORTH, PAUL STEABBEN
Applicants: PLAS PLUGS LIMITED
Application year: 1985
Main classification: H02G1
IPC codes: H02G1