Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02G—INSTALLATION OF ELECTRIC CABLES OR LINES, OR OF COMBINED OPTICAL AND ELECTRIC CABLES OR LINES
  • H02G1/00—Methods or apparatus specially adapted for installing, maintaining, repairing or dismantling electric cables or lines
  • H02G1/12—Methods or apparatus specially adapted for installing, maintaining, repairing or dismantling electric cables or lines for removing insulation or armouring from cables, e.g. from the end thereof
  • H02G1/1202—Methods or apparatus specially adapted for installing, maintaining, repairing or dismantling electric cables or lines for removing insulation or armouring from cables, e.g. from the end thereof by cutting and withdrawing insulation
  • H02G1/1204—Hand-held tools
  • H02G1/1207—Hand-held tools the cutting element not rotating about the wire or cable
  • H02G1/1209—Hand-held tools the cutting element not rotating about the wire or cable making a transverse cut
  • H02G1/1212—Hand-held tools the cutting element not rotating about the wire or cable making a transverse cut using wire or cable clamping means

Definitions

• This invention relates to wire stripping apparatus as defined hereinafter, and in particular - but not exclusively - this invention concerns a hand-held tool adapted and arranged to assist the removal of an end portion of a layer of insulating material from one or more elongate electrical conductors which that layer surrounds.
• the invention may instead concern a bench- mounted production machine for stripping an insulating layer from electrical conductors.
• the apparatus of this invention may be arranged for use with a wide variety of elongate filamentary members, to assist the removal of at least one layer which surrounds that member.
• the apparatus could be arranged to assist the removal of a protective sheath from a fibre-optic filament.
• the apparatus may be arranged to assist the removal of an insulating sleeve from an electrical conductor or a group of conductors which latter may also have a separate insulating layer for each conductor. All such apparatus are referred to herein as 'wire stripping apparatus' and references to 'wire' and 'insulation' should accordingly be construed broadly, as the context may require.
• wire stripping apparatus many of which are in the form of hand-held and hand-operated tools, adapted to assist the removal of insulation from electric wires such as are encountered in association with electrical equipment and appliances. Many of these tools require specific adjustment or setting-up in order to allow them to be operated with any given size of wire, though there have been proposals for self-adjusting tools, which automatically adjust to perform an effective stripping operation on a range of wire sizes. Many of the designs of wire stripping tools are able to perform adequately when used in conjunction with relatively soft insulation such as is often found on wires intended for connecting electrical appliances to wall outlets, but those tools usually are of only limited benefit when used in conjunction with wires having relatively hard insulation, such as are employed for the fixed wiring of a building.
• such fixed wiring usually is in the form of a pair of separately insulated principal conductors disposed within an outer sheath, an uninsulated earthing conductor extending between and parallel to the two principal conductors.
• the power wiring is usually completed with conductors of 2.5mm 2 cross-sectional area, whereas the lighting wiring usually has conductors of either l.Omirr or 1.5mm cross-sectional area.
• a relatively hard grade of polyvinylchloride is commonly used for the outer insulating sheath as well as for insulating the individual principal conductors .
• One of the principal aims of the present invention is to provide wire stripping apparatus (as defined above) which is able to assist the removal of insulation from a wire, whilst being able to adjust automatically to a wide range of wire sizes.
• wire stripping apparatus which comprises a body defining an aperture in which may be received a wire to be stripped, a cutter having a cutting edge arranged to cut into a wire lying in the aperture which cutter is mounted for sliding movement generally along the length of the aperture from a home position where a wire to be stripped may be inserted into the aperture, means controlling the movement of the cutting edge in a direction generally transverse to the length of the aperture which means includes cooperating cam surfaces on the cutter and on a surface over which the cutter slides, and a self-jamming cleat assembly for clamping the wire and cooperating with the cutter whereby sliding movement of the cutter away from its home position brings the cleat assembly into a wire-clamping position.
• Apparatus of this invention may be configured as a hand-held tool arranged principally for the stripping of the wires used in the fixed wiring of a building, when in-situ for the purpose of so-called second- fixing.
• the appratus may be arranged for bench-mounting.
• the self-jamming cleat assembly includes a pair of cleat jaws disposed one on each side of said aperture whereby the wire may be positioned therebetween, the jaws being configured so that on contacting the wire as the cutter moves away from its home position by virtue of the cooperation between the cutter and the cleat assembly, the jaws are urged more firmly to clamp the wire as the wire is pulled by the cutter in the direction of movement thereof.
• the jaws may be spring-urged into or away from a wire-clamping position, with the jaws being moved in the opposite sense against the spring-action by the cutter. It would of course be possible for the cleat assembly to have only one cleat jaw operating in conjunction with an opposed anvil whereby the wire may be positioned between the jaw and anvil.
• One suitable form of self-jamming cleat assembly may comprise a pair of pivoted jaws spring-urged to positions where the jaws move towards each other to clamp a wire disposed therebetween, the cutter when in its home position engaging those jaws and pushing them to positions where they are clear of a wire disposed therebetween; on the cutter moving away from its home position, the jaws may then move to engage a wire.
• a more preferred arrangement is however for the self- jamming cleat assembly to comprise two jaws each of which is slidably mounted within the body and cooperates with a cam surface over which the jaw slides, which cam surface serves to deflect the jaw inwardly of the aperture during sliding movement of that jaw.
• the cutter has two cutting edges arranged one on each side of the aperture, whereby the cutter will cut into the insulation of a wire from both sides thereof, to assist the severance of the portion of the insulation to be removed.
• wire stripping apparatus which comprises a body defining an aperture in which may be received a wire to be stripped, a pair of wire clamping jaws arranged for relative sliding movement with respect to the length of the aperture in the body, each jaw sliding over an associated camming surface arranged to move the jaw inwardly towards the other jaw as the jaws are moved away from a home position, a cutter also mounted for sliding movement along the length of the aperture and having a pair of wire-cutting edges disposed adjacent and between said jaws, releasable means coupling together the cutter and the pair of jaws, and motion means for imparting movement to the cutter with respect to the aperture, whereby the pair of jaws are moved by the cutter upon movement thereof until the jaws grip a wire extending therebetween, whereafter the jaws are released from the cutter upon continued movement of the cutter.
• the pair of jaws together with its associated camming surface serve as a self-jamming cleat assembly, to grip a wire the insulating layer of which is to be stripped by the apparatus.
• movement is imparted to the jaws by movement of the cutter until such time as the jaws contact a wire disposed therebetween; thereafter, continued movement of the cutter will free the releasable means whereby the cutter will move relative to the jaws which latter will remain substantially stationary with respect to the wire, the cutting edges during this stage penetrating the insulation of the wire. Further continued movement of the cutter will pull on the partially-severed portion of the insulation, in the direction away from the main part of that insulation clamped between the jaws.
• said releasable means comprises spring means co-acting between the pair of jaws and the cutter, which spring-means requires some force to break the connection between the cutter and the pair of jaws. Once the connection has been broken, there may be little - if any - frictional force connecting the cutter to the pair of jaws.
• a spring may be used to drive the jaws to a wire-clamping position.
• the pair of jaws may be formed from a single strip to have a generally U-shaped profile, the cutter being similarly formed and adapted to fit within the pair of jaws.
• the body may include a pivoted handle, which handle is connected to the cutter so that pivoting movement of the handle imparts sliding movement to the cutter, the cutter in turn imparting sliding movement to the pair of jaws until such time as said releasable means is released.
• the apparatus includes a wire cutter which, in a preferred embodiment of hand tool of this invention, comprises a moving blade attached to said pivoted handle and co-operable with a fixed blade mounted on the body.
• a preferred form of hand-tool of this invention includes means to effect such folding of an exposed single-core conductor, following the stripping of the insulation therefrom. Such folding conveniently is effected in two stages, the first stage commencing the fold and-the second stage crimping the partly-folded end portion into a completed fold.
• the first stage of the folding action is performed by interaction between a slot having a U- shaped base wall and a blade adapted to pull a wire laid transversely of the slot towards the base of the slot, so that the wire takes up a U-shaped profile. Then, that folded wire may be inserted into a second slot having a planar base wall, a blade crimping the folded wire against the planar base wall to complete a tight fold.
• Figure 1 is a side view of an embodiment of a wire stripping tool
• Figure 2 is a vertical sectional view through the tool of Figure 1 taken on line II-II marked on Figure 5, with the parts thereof set in a starting position
• Figure 3 is a view similar to that of Figure 2, but with the parts displaced from the starting position
• Figure 4 is a plan view of the tool of Figure 1
• Figure 5 is a front view of the tool of Figure 1;
• Figures 6 and 7 are detailed views on an enlarged scale of the base regions of a clamping member and cutter, in the positions illustrated respectively in Figures 2 and 3.
• a hand tool intended for the stripping of insulation from the end portion of a variety of kinds of wires, such as may be encountered in domestic and contracting situations; these may range from relatively light-weight flexes for connecting electrical appliances to fixed wiring outlets, to the fixed wiring itself, including lighting and power cables known as flat twin or three core-and- earth cables of 1, 1.5, 2.5, 4 and 6 mm 2 cross- sectional area conductors.
• the tool is configured to allow the cutting of wires to length, the separate stripping of the outer sheath from a cable having more than one separately insulated wire, the stripping of insulation from individual wires, and the folding-over of a stripped single-core conductor, ready for termination.
• the stripper comprises a moulded plastics body 10 including a handle 11 projecting from one end of that body, and a lever 12 pivoted to the main body by pin 13 such that the lever is generally opposed to the handle 11 and may be moved closer thereto by a user grasping both the handle 11 and lever 12, and squeezing those components closer together.
• the body 10 may be moulded in one piece and includes a pair of side walls 14 joined by an upper edge wall 15A and a lower edge wall 15B, a window- opening 16 being formed in each side wall 14.
• the body 10 defines an aperture in which a wire to be stripped may be inserted from the "front" end 17 of the tool and, if necessary, out of one of the window- openings 16 in a side wall 14.
• the edge walls 15A and 15B define respective camming surfaces 18 and 19.
• a generally U-shaped clamping member 20 formed from spring steel is disposed in the space enclosed by the side walls 14 and edge walls 15A and 15B, the clamping member being formed to define a pair of clamping jaws 21 and 22 adjacent the front end 17 of the tool.
• Adjacent each clamping jaw is a respective abutment 23 and 24, co-operable with the adjacent camming surface 18 and 19, respectively.
• the end of the clamping member 20 remote from the jaws 21 and 22 is restricted from moving towards the upper side wall 15A by part of a sliding bar 25 (to be described below) itself in engagement with a fixed blade 26 fitted into the body 10; and is restricted from moving towards the lower side wall 15B by a moulded insert 27, fitted between the side walls 14. Movement of the clamping member 20 out of the front end of the tool is restricted by a peg 28 on the insert 27, engaged in a slot (not shown) in the clamping member; and movement of the clamping member to the right (in Figures 2 and 3) is limited by leg 29 of the insert 27. Though the position of leg 29 is fixed, it could be made adjustable or replaced by an adjustable stop such as a rotatable cam, to allow fine adjustment of the stripping depth.
• a generally U-shaped cutter 33 formed from a spring-steel blade , which cutter has a pair of cutting edges 34 f ormed at it s f ree ends , the cutting edges being defined in such a way that an abutment 35 is defined adj acent each cutting edge which abutment is able to co-operate with a cam surface defined by the inner surface of the clamping member forming the respective adjacent abutment 23 or 24.
• the base 36 of the cutter 33 normally lies adjacent the clasps 31 of the clamping member 20 as shown in Figure 6; on movement of the cutter 33 to the right (in Figure 2), the engagement of the clasps 31 with the cutter base 36 pull the clamping member to the right until the clamping member meets a resistance; the clasps are then forced open over the cutter base 36 (as shown in Figure 7), to allow the cutter to continue its movement as shown in Figure 3.
• the upper side of the cutter 33 is slotted centrally, adjacent the cutter base 36.
• the lever 12 includes a profiled plate 37 defining a slot 38 having a leg 39 fitting into the slot adjacent the base 36 of the cutter. Movement of the lever 12 in the direction of arrow A causes leg 39 of the plate to act on the base 36 of the cutter, to move the cutter to the right.
• a spring 40 acts between the plate 37 and a pin 41 formed on the insert 27, to urge the lever to the position shown in Figure 2, in which part 42 of the plate 37 abuts the cutter base 36 and leg 39 prevents further leftward movement of the cutter.
• the plate 37 extends beyond pin 13 to form a cutting blade 43, co-operable with the fixed blade 26 to form a wire cutter.
• the co-operating parts of the blades 43 and 26 are hardened, to allow the cutter to sever copper wires as well as any insulating material thereon.
• the sliding bar 25 has its "front" end 44 retained adjacent the edge wall 15A by means of lugs (not shown) moulded into the side walls 14.
• the plate carries an upstanding blade 45 projecting through a slot 46 in the upper edge wall 15A, and the opposite end of the sliding bar 25 defines a slot in which is received the plate 37. Movement of the lever 12 in the direction of arrow A will thus slide the bar 25 to the right.
• the slot 46 has a "horizontal” component in the plane of the outer surface 47 of the wall 15A, and a “vertical” component 48 extending through the edge wall 15A.
• a wire laid on surface 47, between the blade 45 and shoulder 49 of the wall 15A will be pulled into this horizontal component and will thus be shaped into a U- profile; that folded-over wire may then be inserted into the vertical component 48 so that the blade 45 will crimp tight the end portion of the wire.
• the wire is passed through the opening at the front end 17 of the tool and, if appropriate, out of one of the window apertures 16, when the tool is set in its home position as illustrated in Figure 2.
• lever 12 is moved in the direction of arrow A, pulling both the cutter 33 and the clamping member 20 to the right.
• the abutments 23 and 24 ride up the camming surfaces 18 and 19 until the clamping jaws 21 and 22 contact the insulation of the wire to be stripped.
• a single stripping operation may remove, say, 150mm of outer sheath.
• a similar length of sheath may still be removed, but by taking a number of 'bites' along the wire end portion, of, say, 25mm each, or even less.
• each cutting edge 34 should project by the required extent inwardly of its associated jaw when the tool is in the position of Figure 2. Then, when the jaws 21 and 22 clamp a cable the edges will already have penetrated the cable and no further inward movement will be required; instead, the cutting edges may simply slide along the adjacent clamping member surfaces.

Landscapes

• Removal Of Insulation Or Armoring From Wires Or Cables (AREA)

Applications Claiming Priority (4)

Publications (1)

Family

ID=26296717

Family Applications (1)

Country Status (2)

Families Citing this family (3)

Family Cites Families (2)

• 1991
  • 1991-02-22 WO PCT/GB1991/000282 patent/WO1991013481A1/en not_active Application Discontinuation
  • 1991-02-22 EP EP19910904672 patent/EP0516683A1/de not_active Withdrawn

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events