US 2361402 A
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Oct. 31, 1944. J. R. JAMIESON METHOD OF PRQDUCING THE CUTTING PORTION OF TOOLS Filed Se i. 3, 1941 n o S e .L m RJ n m m m J m.
Patented Oct. 31, 1944 ME'rnon or PRODUCING THE CUTTING 1' PORTION OF'TQOLS Jay R: Jam-ieson, Cleveland, Ohio Applicationseptember 3, 1941, Serial No. 409,342 I 10 Claims.
My invention relates .to .tools. and. more particularly to tools: for-cutting. and stripping. -in-- sulationfrom'wires and to an improved method of producing such .tools.
In making electrical. connections with conduc- 'tive wires having. insulated-covers, it-is desirable.
to provide. a simple. tool for readily removingportions'. of the insulationf'rom the wire. Heretofore, in providing tools for such purposes,.-it;has.-
beenthe practice tozprovide either a somewhat complicatedtool or a device which is adapted to. be attached'to tables, benches; or the like. For
simple operations, such to.ols..or devices are not In Sim-.2
only cumbersome but are alsoexpensive. pletools whichhave beendevised for'suoh'purposes, thecutting edges of the tool is not only usually exposed but such tools are generally con.-.
structed in such. a manner that it is difiicult to strip theinsulation from the. wire after the cutting: operation.
It is an object of the presentinvention to pro-= vide an improved :tool for cutting andstripping insulation from wires that. may be constructed.
by simple forming operations, is effective in service, and which is comparatively small'in size so that it maybe readily carried inthe pocket or kit of the electrician or operator, and to anim-- proved method of producing such tools.
I Another object of my invention is to providean improved tool having a cutting portion anda handle; the cutting portion being integrally or firmly united to the handle so that thetool may' beheld firmly in contact with the insulation during both the cutting and stripping operations.
A further object of my invention is to provide an improved'tool that may be readilysharpened Fig. 3 is aside elevational view with parts in.
section of a modification of my improved tool,
showing the cutting edges in thesame .plane as. one of the=faces of the disk and the disk. at-
tached to a woodenhandle;
Fig.4 isafront view of'a ,disk having a central.
opening, the disk being embossed in preparation.
for subsequent operations; I
Fig.5 is. a cross sectional view onthe line 5-5 of Fig. 4;.
Fig. 6 is front view-of the completed disk;
Fig. 7 is: a cross-sectional view on the line 'l'1.
* of Fig- 6, showing the contour of the cutting edges, the dotted lines. indicating the portion. of the embossment which has been removed',"
Figs. 8 and 9 are detailviews showing modifications of the cuttingnotches or slots formed thedisk;
Fig. 10 is a perspective View of: a modified form of cutting and stripping tool. adapted to be uti-- lized .in; cutting and stripping insulation from wires. having: a comparatively large-diameter;
Fig. .11 isa plan view of aportionof the blank from which the .tool shown in Fig. '10 is formed, the blankbeing shownembossed and the dotted lines; indicating. the planes upon which the. metal is bent in. forming thetool;
Fig. -12 is. a. crosssectional .view on the line |2l2 of Fig. 11;.
Fig. 13. is ailongitudinal sectional view of...a portion of the; tool-.shown in Fig-10, parts of the tool being shown embedded inthe insulation of the wire;.and
Fig, 14 is across sectional view on. the line l4-l4of Fig. 13.
Referring to. the modifications-.shownin Figs- 1 to '7, inclusive of the. drawing, my improved tool comprises, a diskl which is firmly secured. to ahandle. 2 by any suitable, means, suchas a screw 3, or when the handle is formed of metal, the end portiorrof the metal may be extended through a centraljopeningin the diskandzbent' or. flanged oventhe. metal disk as shown at .311 in Figs. 1 and.2.
As illustrated the .disk .I has three cutting: slots or notches 4, 5 and IL-each of which: is: adapted to: receive .an insulated-wire of -a different. size;v althoughobviously the disk may be: provided witha smaller or. larger'number .of such slots or notches. Eachmof'theslots is provided with cutting edges 7a and-8a whichare, adapted to cut the insulation from the wireasit is forcedinto the slots.
According to'my inventionrthe cutting edges'.
7a and. 8a. .are formed 1115.8 simple. and economical manner. As. indicated-in Figs: .4;and' 5, 10f the. drawing, embossments. are formedin: the disk.
which is to be subsequently formed and I do not 4 desire to be limited in this respect. For instance,
the embossments may be rectangular in shape. Preferably, however, the embossments extend from the outer periphery of the disk to a point a substantial distance from the center and the side edges of the embossments converge toward each other and are rounded at their inner portion into various shapes as illustrated in the drawing. As shown in Fig. 4, the outer edges I of the embossments are rounded in a substantially spherical shape, in Fig. 8 the outer edges of the embossments terminate in a substantially circular portion as indicated by the numeral ll, while in Fig. 9 one of the outer edges of the embossments extends substantially radially and the other edge is rounded outwardly as indicated by the numeral l2.
After the embossments are formed, the metal forming the embossments is laterally ground to remove a sufiicient portion of the embossments to form slots or notches having sharp cutting edges whichextend toward the opening in the slot. The lateral grinding or the rounded portion of the embossments also serves to form a rounded inner portion with cutting edges extending toward the slot. The embossmentsmay be of the same size or of different sizes. When the embossments are of the same or of a standard size, slots having various sizes may be provided by grinding the embossments to various levels or if different size embossments are formed, slots of various sizes may be produced by grinding to the same level.
As illustrated in Fig. 5, the metal may be ground to a plane as indicated by the line XY to form cutting edges 1 and 8 in which the outer and inner portion of the metal of the cutting edge are at an acute angle to each other.
To enable the tool to be readily sharpened when it becomes dull, however, theembossments are usually ground to a plane spaced from the front face of the metal as indicated by the line AB or CD to form cutting edges la. and 8a as shown in Fig. l orcutting edges lb and 8b as shown in Fig. 5. Instead of grinding the metal to the plane designated by the lines X-Y and AB, the upper portion may be cut or punched out upon a line havinga contour sub-' stantially vertical with edges l and 8 or Ia and v 8a, thereby removing the maiior portion of the embossment, and the remaining metal maybe ground down to the desired level. For instance, the metal may be punched or cut out on a'contour such as shown by the openings of the slots in Fig. 6 and the edges of the metal may then be ground laterally down to the shape shown in Fig. '7. It is not essential, however, that the embossments hall be formed prior: to the cutting or piercing operation as slots may be first punched from the metal and the sides of the metal adjacent each slot may be formed or extruded outwardly to provide metal surfaces extending beyond the normal plane of the metal,
such as shown in Fig. 14 which may then be ground to the desired level.
In the preferred form of my invention, however, a second embossment is formed within the firstembossment, as shown in Figs. 4 and 5, both embossments being-formed in onestamping operation, and the metal forming the second embossment is ground to a plane as indicated by the line CD to form cutting edges lb and 8b.
In the latter case the angle formed between the inner and outer edges of the metal is not atsuch is ground to a plane along the lines X--Y or AB and consequently the metal forming the cutting edges is not so apt to be broken during the cutting operation. When the metal is formed in such manner, the second embossment may be completely removed without any punching operation and the cutting edges are spaced outwardly from the face of the disk and are conse quently in a position to be readily sharpened when they become dull, or after they have been sharpened several times, they may be ground down sufiiciently to form a cutting edge for a wire of the next larger size.
After the embossment on the disks have been ground, the disk is in the form shown in Fig. 6 with the cutting edges converging radially inwardly and terminating in a rounded portion with cutting edges, or the rounded portion of the slot may be more pronounced as indicated by the numeral I6 in Fig. 8, or it may be slightly offset as indicated by the numeral l! in Fig. 9. It will be particularly noted that the outer faces of the cutting edges are substantially flat and that the cutting edges form the boundaries of the slot. The cutting edges are therefore not.
the handle is made'of metal, the end of the handle attached to the disk is preferably bent inwardly to form a shoulder l9 and is then ex-' tended through the aperture and-bent back or flanged over the disk. The shoulder and flanged portion thus formed preferably extend approximately to the inner portion of notches l5 and form a firm support for the disk.
When the handle is formed of wood as shown in Fig. 3, the disk may be attached to the handle by any convenient means, such as a screw, 3, which extends through the aperture 18 and is embedded in the wood. If a plastic material is used, a threaded insert may be embodied in the plastic during the molding operation which protrudes beyond the end of the molded material to receive the disk and a. nut for securing the disk in place. In attaching the handle in the manner specified, it willv be noted that the central part of the disk fits snugly against the fiat end o'f the handle and that substantially the entire area of the disk extending radially inwardly from the notches bears against the end of the handle. The handle therefore provides a strong rigid support for the disk.
In stripping insulation from wires, the insulated wire is inserted through the appropriate slot in accordance with the size of the wire and into the rounded portion at the end of theslot. As the insulated wire is forced inwardly; the edges la and 8a cut the insulation. To insure complete cutting of the insulation, the wire is held in one hand and the handle in the other, and after the wire has been inserted through the slot into the rounded portion, [the handle is turned to make a complete cut and is then pulled to remove the insulationfrom the end of the wire. To insure proper cutting of th insulation and to provide a better grip on the insulation for stripping purposes, I have found it desir-' disk 6 is atportion as-ind-icated am Kiri-Fig.6; or -ifdesire d thedin'nen portionof thaslotinay be substantially circular-as shown at- I 6; or may becfiset' as-shown at-il 'in' Figp In the modifications shown-in Fig Wand- 9, -iti willbe understood that the rounded portions as well as the: sides ar-e pro- Vi'dect with =cuttin'g edges;
A modifie'd fornr of my invention is: shown in Ffgs i lfl to :14 'of thedrawing: and is-designed for cutting insulation -frm1. wires 1 of comparatively largeifdiametersf Aseillustrated, the handle is formed integral with the cutting iportionv. of the to'olgthes tool being-preferablyformed. of an intea- 'gralspiec'e' of 2 metal; Aszindicated in Fig.1 102 of then-drawing;thea-metal fromiwhich the tool is formed-- is' bentz downwardlyat; both sides and cuttingJ-portion-With' diverging sidewalls and a horizontally extending:puttingportionwith diverging- ;side: walls.
In cutting-insulation with 12116113001 shown in Figsto 14, inclusive, cutting-edge 22 is forced downwardly throug-hthe top of the insulation and cutting-edges '23 and 24 ,split the insulation alonghthe-sides and-as the tool is pulled for- -wardly; the insulation is-removed as it is slit.
Intheformof tool-\shownin Figsbl to 7, inclu- I sive,- of the drawing, means. may also be provided to. out both the insulation andthe wire. For this pu rpose, one.of theembossments on the disk may be, formed withbothlouter edges extending radiallyfin'ward and consequently when this embossment is' ground l-aterally-,vV-shaped cutting edges 253m formed. Iniforcing the insulated wire into aislo t of this type, itwill be apparent that the edges 25tvill -out both the insulation and the wire.
It'willfbenotedthatcutting edges-25 'of this embossment are; spaced outwardly from the plane otthemet'al'and consequently they may be readily sharpenedwhen they become dull.
What I claim is:
1. The method of preparing the cutting por-- tion of an insulating cutting tool which comprises shaping a portion of a flat sheet of metal to form an embossment protruding outwardly from the normal plane of the metal and having a concave inner surface and converging side walls extendbossment :and' in a directitm :subs'tantiallyvpenpendicular: thereto: to: form: a substantially; v shaped slothaving'rrcutting edges: facing-search other aandiwitht; the narrow portion l of-l :the; ..V- shapedaslot spaced inwardly fronr the outer edge of: th'e .:metal without =disturbingthe metal in the norma'l'xplaneaot the-sheet:-
3. The method of preparingiadisk composed .ofr. fiatsheet metal to: .fo'rm' the; cutting portion 1 iofratooll which comprises: shaping :japortion of theadi-sktotform arr-embossment protruding outing inwardly a substantial distance from the shaped slot spaced inwardly from the outer edge of the metal without disturbing the metal in the normal plane of the sheet.
2. The method of forming the cutting portion of an insulating cutting tool which comprises extruding from a flat sheet of metal a portion thereof in the form of an embossment having converging side walls extending inwardly from the edge of the metal and then grinding the metal along substantially the entire length of the em- 76 wardly'from the normal-plane of the metal and having: a concave inner surface and .converging side walls extending inwardly toward the. center .from i the: outer; periphery of the-disk" and then grinding away throughout: substantially the entire lengthsoft the embossment and substantially perpendicular-thereto 'asufiicient amount; of metal constituting the central portion oi-the embossment to z form a 1 substantially V-shaped slot having: cutting edges-facing-each other and of sufficient .sizeto receive and cutthe insulated portion of -arwire as .it is. forced inwardly through the-slot.- p
4; Themethod of preparingv a disk composed of flat sheet metal to. form the cutting portion of. a. toolpwhich comprises. shaping portions .of the disktto formvaplurality of spaced. embossmerits oil-different sizes protruding outwardly (from the'norma'l plane of the metal. and each of which has side walls converging inwardly toward the centerwof the disk from. its outer periphery,.and. then grinding away along the entire length of each embossment and in a direction substantiallyperpendicular thereto a sufficient amount o f .metal from thecentral, portion ,of each embossment to form V-shaped slots of different sizes, ,each of which has cutting edges facing each other ofsufiicientsize to receive and out the insulation fromv a wire.
5. The. method oipreparing a disk composed of flat sheet metal to form-thecuttingportion of a tool. which comprises shaping the. disk i to form an embossment: protruding outwardly from g the normal plane. of the metal having: a concave inner surface andlsid'e walls tapering frornithe .outer..periphery,of the disk towardthecenter and at least one of said side walls being rounded outwardly adjacent its inner portion and merged with the other side toform an enlarged arcuateshaped portion spaced from the center of the disk and then grinding away along substantially the entire length of the embossment and in a direction substantially perpendicular thereto a suflicient amount of metal constituting the central portion of the embossment to form a substantially V-shaped slot having cutting edges facing each other and of sufficient size to cut insulation from an insulated wire forced inwardly through the slot and to form an arcuate-shaped opening having cutting edges to receive the wire after it has been forced inwardly through the slot.
6. The method of preparing a' disk composed of flat sheet metal to form the cutting portions of a tool which comprises shaping the disk to form an embossment protruding outwardly from the normal plane of the metal and having a concave inner surface and side Walls tapering from the outer periphery of the disk toward the center of the disk and then grinding away along substantially the entire length of the embossment and ina direction substantially perpendicular thereto a sufiicient amount of metal The method of preparing constituting the central portionof the embossimenttto 'form a substantiallyr V-shaped .slot having cutting edgeszfacing each .other and of sufiicient size to cut insulation from an insulated wire forced inwardly throughvthe' slot but said grinding being insufiicientto'reduce .any portion of said embossment to the'normal .plane or the'metalinsaid sheet.
a disk composed of flat sheet metal to form the cutting portion of a tool which comprises shaping the disk to form an embossment, protruding outwardly from the normal plane'of the metal having a concave inner surface and side wallstaper'ing from the outer periphery of, the disk toward the center maiorz r no t s 'eon 6 995 811 2 o m a u ta t a ly ha dn l t haw ine ui ies edges facing each other andextending substantially the entirelength of-the' first embossment.
9. The method of, preparing a dislc'composed of fiat-sheet. metal to form the cutting portion of a tool which comprises shaping a portion .of the disk;to formva'first embossment, protruding outwardlyirom the normal plane of the metal at least one of which'is rounded outwardly -ad- V jacent its inner portion and merged with the other side wall to form'an' enlarged 'arc'uateshaped portion spaced from the center of the disk, and then laterally grinding away along substantially the entire length of the embossment and in a direction substantially perpendicular thereto a 'suificient amount of metal constituting the central portion of the embossment to form a substantially V-shaped slot hav- ;ing cutting edges 'facing each other and of sufficient size to cut insulation from an insulated wire forcedly inwardly through the slot and to form ariarcuate-shaped opening to receive the wire after ithas been forced inwardly through the slot but the extent of said grinding being insuflicient to reduce any portion of said embossment to the normalplane of the metal in said sheet. w 8. Themethod of formingthe cutting portion of a tool which comprises shapirig a portion of the fiat sheet of metal to form a first embossment protruding from the normal plane 'of the metal and having converging side walls extend ing inwardly a substantial distance -from the *outer edge of the'metal and a second embossmerit protruding from the first embossment having a concave inner surface and. converging side walls extending inwardly from the-outer edge of themetal to substantially the same distanceas the side walls of thefirst embossment and then laterally grinding away the metal constituting a V-shaped slot having'cutting edges facing each other and of suflicient size to cut insulation from an insulated wire forced inwardly through the slot and an arcuate-shaped opening having cutting edges to receive the wire after it has been forced inwardly through the slot.
g 10. The method of forming the cutting portion ofan insulating cuttin'g'tool which comprises shaping a fiat sheet of metal to form an emjbossmen't protruding outwardly from the normal plane ofthe metal and having a concave inner surface and side walls tapering from the outer edgeof the metal which'merge'to form a rounded portion, grinding away along substantially the entire length of the embossment and in adirec- "tion substantially perpendicular thereto a sufficient "amount of metal constituting the central portion ofv the embossmentto form a' substantially V shaped slot havingcutting edges: facing each other and a cutting edge facing the slot,
and 'thenbending the metal beyond'the embossment and substantially intermediatefthe length of the embossment to form a [substantially yeshaped cutting portionand side'cutting portions diverging away from eachother.
JAY R. JAMIEsonI