US3579825A

US3579825A - Electrician{3 s tool for longitudinally and circumferentially cutting insulation on wire

Info

Publication number: US3579825A
Application number: US779557A
Authority: US
Inventors: Alfred H Powell
Original assignee: Individual
Current assignee: Individual
Priority date: 1968-11-27
Filing date: 1968-11-27
Publication date: 1971-05-25
Anticipated expiration: 1988-05-25

Abstract

This tool has a blade carrying assembly supporting a blade so it can be adjusted for depth of cut and can be set in one position to slit insulation lengthwise on a wire and in another position to cut the insulation around the wire. The blade has graduation marks on it so the depth of cut it is set to make can be read directly. Two wire-guiding members at opposite sides of the blade and the blade-carrying assembly are adjustable toward and away from each other to receive and hold wires of different sizes.

Description

United States Patent 1,885,944 11/1932 Pedersen Alfred II. Powell 19321 108th Ave. N.E., Bothell, Wash. 779,557

Nov. 27, 1968 May 25, 1971 Inventor Appl. No. Filed Patented ELECTRICIAN S TOOL FOR LONGITUDINALLY AND CIRCUMFERENTIALLY CUTTING INSULATION ON WIRE 3 Claims, 6 Drawing Figs.

US. Cl 30/90.7

Int. Cl B26b 27/00 Field of Search 30/90. 1 90.4, 90.7, 91.1, 91.2

References Cited UNITED STATES PATENTS 1,979,487 1 1/1934 Pedersen 30/90.7 2,601,724 7/1952 Jones 30/90.4X 3,091,031 1 5/1963 Grant 30/90.7

Primary Examiner-Granvi1le Y. Custer, Jr. Attorney-Fred C. Matheny ABSTRACT: This tool has a blade carrying assembly supporting a blade so it can be adjusted for depth of cut and can be set in one position to slit insulation lengthwise on a wire and in another position to cut the insulation around the wire. The blade has graduation marks on it so the depth of cut it is set to make can be read directly. Two wire-guiding members at opposite sides of the blade and the blade-carrying assembly are adjustable toward and away from each other to receive and hold wires of different sizes.

ELECTRICIANS TOOL F OR LONGITUDINALLY AND CIRCUMFERENTIALLY CUTTING INSULATION ON WIRE BACKGROUND OF THE INVENTION 1. Field of the Invention My invention relates to an electrician's tool for longitudinally slitting and circumferentially cutting the insulation on electric circuit wire preparatory to stripping it off of the wire.

2. Description of the Prior Art In electric wiring it is common practice to use an ordinary knife to longitudinally slit and circumferentially cut the insulation on electric circuit wire so it can be stripped off and the wire left bare at selected locations to facilitate making electrical connections. Special tools have been devised for doing this work but, as far as known to applicant, none of these have gone into extensive use.

SUMMARY OF THE INVENTION An object of my invention is to provide a simple and efficient electrician's tool which will save time and labor by enabling an electrician to remove insulation from wires faster and with less effort and with greater safety to the hands than can be done with the knives ordinarily used for this purpose.

Another object is to provide an electricians tool having a blade which can be quickly and easily moved rotatively between a position suitable for longitudinal slitting and a position suitable for circumferential cutting of the insulation on a WII'C.

Another object is to provide an electricians tool having a longitudinally adjustable blade with a sharp edge and a beveled end which intersects the sharp edge at an acute angle and forms a cutting tip and having graduation marks which terminate at said sharp edge so that, in sharpening the blade, the beveled edge can be ground to coincide with a graduation mark at the beveled edge and the blade can then be adjusted for any desired depth of cut by a direct reading of the graduations thereon and without the use of any scale or measuring device.

Another object is to provide an electricians tool in which a blade carrying assembly is supported from a handle by two spaced-apart spring steel plates and in which said plates terminate in edge flanges forming tool guiding members which extend beyond an end of the blade carrying member and are adjustable toward and away from each other to best accommodate insulated wires of different diameters. Other objects will be apparent from the following description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view in side elevation of a tool embodying my invention.

F [6. 2 is an end view, on an enlarged scale, of said tool looking in the direction indicated by line 2-2 of FIG. 1.

FIG. 3 is a fragmentary view, partly in section and partly in elevation taken on line 3-3 of FIG. 2, a blade being shown in a different position than it is in FIG. 2.

FIG. 4 is a fragmentary top edge view looking in the DESCRIPTION OF THE PREFERRED EMBODIMENT This tool comprises a handle having two thin spring steel plates 11 and 12 rigidly secured to it and protruding from one end thereof in spaced-apart parallel relation. Preferably the handle 10 is fonned of strong durable plastic or similar material which is an electric insulator. Plates 11 and 12 can be duplicates except that they are made right and left." The plates 11 and 12 are respectively provided, near their outer ends, with guide flanges 11' and 12 which protrude edgewise from the plates in the same direction and cooperate in forming wire-guiding members. The opposed extremities of these wireguiding members 11' and 12 are offset inwardly toward each other by bending them so as to position their wire-engaging parts at the proper distance from each other to most efficiently guide and hold the wires. Also said wire-guiding members 11 and 12 are adjustable toward and away from each other by flexing them and the plates 11 and 12, as hereinafter more fully explained.

A blade carrying assembly composed in part of two

mated blocks

13 and 14 is permanently secured between the plates 11 and 12 and wire-guiding member 11' and 12'. The

blocks

13 and 14 are of generally similar shape and size and have opposed contacting faces provided with longitudinal grooves 20,

FIG. 4. An externally cylindrical blade holder 15 is disposed within the grooves 20. For ease and simplicity of manufacture said blade holder 15 is preferably formed of two similar parts each having a flat side within which is a longitudinal groove. These two parts are welded or otherwise rigidly secured together with the grooves in registration so that the grooves cooperate in forming a guideway for a blade 21. An annular flange 17 of tapered cross secton on each end of blade holder 15 seats in countersunk depressions 18 in each end of

blocks

13 and 14. A setscrew 22 threaded into blade holder 15 securely clamps the blade 21 and holds it in any desired adjusted position. Setscrew 22 can be reached for adjustment through an opening 23 in

blocks

13 and 14.

The two

blocks

13 and 14 are permanently secured together by rivets 24 and these assembled blocks are permanently and fixedly secured between the sideplates 11 and 12 by other rivets 25. The rivets 25 urge the plates 11 and 12 and wireguiding members 11 and 12' against the sides of the

blocks

13 and 14 but said sideplates 11 and 12 and wire-guiding members 11' and 12 are resilient enough so that, by application to them of outward pressure they can be caused to spring apart, as indicated by dash lines in FIG. 2, to provide enough adjustment between parts 11 and 12 to take care of insulated wires of all of the difierent sizes usually used in electrical wiring of buildings.

For the purpose of adjustably moving the wire guiding members apart I provide within the

blocks

13 and 14 two aligned longitudinally

movable pins

26 and 27 the outer ends of which are positioned against the respective wire-guiding members 11' and 12', the

pins

26 and 27 are moved outwardly by the wedging action of a screw 28 which is threaded into a bore 29 in the block 13 and has a tapered end 30 with which the inner ends of both of the

pins

26 and 27 engage. Obviously movement of the screw 28 toward the

pins

26 and 27 will move said pins and the wire-guiding members 11' and 12 outwardly and movement of the screw 26 in the opposite direction will allow spring action to move said wire guiding members inwardly.

One edge portion of the blade 21 is beveled, preferably on both sides, to provide on said blade a fairly sharp edge 31 and the cutting end of said blade, which protrudes from the blade holder 15, is beveled to intersect the edge 31 at an acute angle and form a cutting tip or point 32. Graduation marks 33,

preferably one sixty-fourth of an inch apart are provided on the flat beveled surface of at least one side of said blade and terminate at the sharp edge 31. The blade is sharpened by grinding down the beveled end of the same and, if care is exercised in the sharpening to be sure that the end bevel intersects The blade holder with blade clamped therein is rotatively adjustable in

blocks

13 and 14 through an angle of 90 to selectively position the blade either in a plane parallel to the length of the tool, as shown in FIG. 3, for longitudinal cutting or slitting of the insulation on a wire or in a position crosswise of the length of the tool, as shown in FIG. 4, for circumferential cutting of the insulation on the wire.

The means for rotatively adjusting the blade holder 15, F IG. 6, comprises a pin 34 rigid with the upper end portion 17 of said blade holder 15 and protruding upwardly therefrom. A sleeve 35 fits slidably over the pin 34 and a spring 36 urges the sleeve 35 upwardly. The sleeve 35 has a conical locking member 37 rigid with it and a finger piece 38 of smaller diameter than the member 37 is rigid with and protrudes upwardly from said member 37. The finger piece 38 operates in an arcuate slot 40 in a cross rotate 41. Plate 41 is rigid with sideplates 11 and 12. The center about which slot 41 is described is the axis of blade holder 15. Slot 41 has enlarged

openings

42 and 43 at its respective ends. The centers of

openings

42 and 43 are angularly spaced 90 and the member 37 is adapted to be seated in either of these openings to hold the blade 15 in the position in which it is shown in FlG. 3 for longitudinal slitting or in the position shown in FIG. 2 for for circumferential cutting of insulation on a wire.

For longitudinal slitting of insulation on wire the blade 15 is set parallel to the length of the tool, as shown in FIG. 3, with the tool held in one hand and the wire in the other the wire is positioned between the members 11' and 12', is pressed against the blade and blade holding assembly to imbed the tip of the blade in the insulation and the tool and wire are longitudinally moved relative to each other to slit the desired length of insulation. For circumferential slitting of insulation the blade 21 is positioned crosswise of the length of the tool, as shown in FIG. 2, the wire is positioned lengthwise between members 11 and 1.2 and pressed and held against the blade to imbed and hold the blade tip 32 in the insulation and the tool is then moved around the wire in the proper direction to move the cutting edge of the blade against the insulation and make the cut.

For convenience in circumferential cutting of insulation rightand left-hand users may find it desirable to move the tool around the wire or cable in different directions. To take care of this requirement provision can be made for rotatively adjusting the blade 21 through an angle of l80 by using in place of plate 41 a wider plate having in it an arcuate slot similar to slot 40 except that it is slightly more than 180 in extent and has three enlargements at intervals of 90, the enlargements corresponding to enlargements 42 and 43 of FIG.

Preferably a space or gap of substantial width is left between the inner end of the handle 10 and the

blocks

13, 14 and, at the location of this gap, aligned circular openings 16 are provided in the sideplates l1 and 12 to receive insulation stripping mechanism of the form disclosed in my copending Pat. application Ser. No. 642,096, now U.S. Pat. No. 3,43 l,645 issued Mar. 11, 1969. Also preferably, at the location of this gap, one or more edges of one or both of the sideplates l1 and 12 are sharpened, as indicated by numeral 19 so that at least one of the sideplates 11 or 12 can be used like a knife for cutting purposes, for instance used to cut off pieces of insulation which have been loosened from wire or cable, it being understood that this tool is equally well adapted for use on insulated wire of the single wire type or on insulated electric cable of multiple wire type.

The foregoing description and accompanying drawings clearly disclose a preferred embodiment of my invention but it will be understood that changes in the same may be made.

lclaim:

1. A tool for longitudinally and circumferentially cutting insulation on circuitwire comprising a handle; two spring steel plates rigid with said handle and protruding from an end of said handle; a blade-carrying assembly positioned between said two plates and supported be 0nd and adjacent to an end of the handle by said p ates; a bla e holder supported for rotative adjustment by said blade; a blade holder supported for rotative adjustment by said blade-carrying assembly through an angle of substantially about an axis generally perpendicular to the axis of the handle; a blade longitudinally adjustably supported by said blade holder, said blade terminating at one end in a cutting tip which protrudes from said blade holder; two spaced-apart wire-guiding members integral with the outer end portions of said plates and positioned at the sides of said blade-carrying assembly and protruding beyond an end of said blade-carrying assembly at opposite sides of the cutting tip of the blade, said wire-guiding members being adjustable toward and away from each other and the terminal portions of said wire-guiding members being offset toward each other beyond the adjacent end of the blade-carrying assembly, said cutting tip being applicable to insulated wire guided and held between said two wire-guiding members, said blade holder providing rotative adjustment of said blade between two positions in which it is respectively adapted for longitudinal and circumferential cutting of the insulation on circuit wire disposed between said two wire-guiding members.

2. The tool as claimed in claim 1 in which two adjusting pins are supported by the blade-carrying assembly with their outer ends positioned to contact the respective wire-guiding members, and a screw is threaded into said blade-carrying assembly and has a tapered part positioned between the inner ends of sald adjusting pins adapted to move said pins and said wireguiding members outwardly.

3. The tool as claimed in claim 1 in which the blade is flat and has a sharp edge and a beveled end which intersects the sharp edge at an acute angle and forms a cutting tip, and in which transverse graduation marks are provided on the blade and terminate at the sharp edge of the blade, said graduation marks providing a direct reading of the distance of protrusion of the blade from the holder.

Claims

1. A tool for longitudinally and circumferentially cutting insulation on circuit wire comprising a handle; two spring steel plates rigid with said handle and protruding from an end of said handle; a blade-carrying assembly positioned between said two plates and supported beyond and adjacent to an end of the handle by said plates; a blade holder supported for rotative adjustment by said blade; a blade holder supported for rotative adjustment by said blade-carrying assembly through an angle of substantially 90* about an axis generally perpendicular to the axis of the handle; a blade longitudinally adjustably supported by said blade holder, said blade terminating at one end in a cutting tip which protrudes from said blade holder; two spaced-apart wire-guiding members integral with the outer end portions of said plates and positioned at the sides of said blade-carrying assembly and protruding beyond an end of said blade-carrying assembly at opposite sides of the cutting tip of the blade, said wire-guiding members being adjustable toward and away from each other and the terminal portions of said wire-guiding members being offset toward each other beyond the adjacent end of the blade-carrying assembly, said cutting tip being applicable to insulated wire guided and held between said two wire-guiding members, said blade holder providing rotative adjustment of said blade between two positions in which it is respectively adapted for longitudinal and circumferential cutting of the insulation on circuit wire disposed between said two wire-guiding members.

2. The tool as claimed in claim 1 in which two adjusting pins are supported by the blade-carrying assembly with their outer ends positioned to contact the respective wire-guiding members, and a screw is threaded into said blade-carrying assembly and has a tapered part positioned between the inner ends of saId adjusting pins adapted to move said pins and said wire-guiding members outwardly.