US3864829A

US3864829A - Cutting tool

Info

Publication number: US3864829A
Application number: US387483A
Authority: US
Inventors: John Williams
Original assignee: Individual
Current assignee: GLASS SPECIALTIES Inc A WISCONSIN CORP
Priority date: 1973-08-10
Filing date: 1973-08-10
Publication date: 1975-02-11
Anticipated expiration: 1992-02-11

Abstract

The tool presents a combination of specially lune-shaped, object-excising cutter rigidly mounted on a transparent base, and a similarly shaped stripper also carried by the base and resiliently biased to yield and move within and relative to the cutter. The cutter has a cutting edge defining a crescent-like cutter contour, this edge projecting from the mounting base in the direction in which the tool is manually translated in a cutting operation. The cutter is a two-piece one presenting generally nested, oppositely facing surfaces of arcuate lunar shape; and these surfaces are respectively mated externally, mounted and braced by transparent Lucite blocks, which coact to constitute the cutter holding body. To this end each cutter knife edge or razor blade component is rigidly secured to its own mated mounting block by screws tapped into the latter; and said blocks are in turn rigidly secured together by a pair of bolts or studs spanning the meeting line of the blocks. The knife edges or blades of the two cutter lunes converge at opposite extremities to a quite close adjacency to one another, but are nevertheless still a trifle spaced sufficiently to avoid forming thin feather edges on the excised piece, in the interest of insuring a clean stripping of the latter from the cutter. The stripper plate is normally disposed in the horizontal plane of the actual razor edge of the cutter. Springs enable the stripper plate to yield upwardly within the cutter as it slices downwardly through the excised sheet, then as fully compressed to automatically eject the excised product from the cutter.

Description

United States Patent [191 Williams 1 CUTTING TOOL [76] Inventor: John Williams, 18331 Tipsilo Lake Rd., Fenton, Mich. 48430 [22] Filed: Aug. 10, 1973 [21] Appl. No.: 387,483

[52] US. Cl. 30/130, 76/107 R [51] Int. Cl B26b 3/08 [58] Field of Search 30/128, 130, 301, 302, 30/303, 316, 344, 358; 83/684, 128; 76/107 R [56 References Cited UNITED STATES PATENTS 625,636 5/1899 Bass 30/130 1,082,985 12/1913 Wilder 83/684 X 1,649,803 1l/l927 Boirsky 30/130 2,612,123 9/1952 Nord 30/316 2,799,929 7/1957 Kurianski.. 30/301 2,821,871 2/1958 Sarno 83/128 X 3,531,863 10/1970 Sandborn 30/301 Belknap [57] ABSTRACT The tool presents a combination of specially luneshaped, object-excising cutter rigidly mounted on a [451 Feb. 11,1975

transparent base, and a similarly shaped stripper also carried by the base and resiliently biased to yield and move within and relative to the cutter. The cutter has a cutting edge defining a crescent-like cutter contour. this edge projecting from the mounting base in the direction in which the tool is manually translated in a cutting operation. The cutter is a two-piece one presenting generally nested, oppositely facing surfaces of arcuate lunar shape; and these surfaces are respectively mated externally, mounted and braced by transparent Lucite blocks, which coact to constitute the cutter holding body. To this end each cutter knife edge or razor blade component is rigidly secured to its own mated mounting block by screws tapped into the latter; and said blocks are in turn rigidly secured together by a pair of bolts or studs spanning the meeting line of the blocks. The knife edges or blades of the two cutter lunes converge at opposite extremities to a quite close adjacency to one another, but are nevertheless still a trifle spaced sufficiently to avoid forming thin feather edges on the excised piece, in the interest of insuring a clean stripping of the latter from the cutter.

The stripper plate is normally disposed in the horizontal plane of the actual razor edge of the cutter, Springs enable the stripper plate to yield upwardly within the cutter as it slices downwardly through the excised sheet, then as fully compressed to automatically eject the excised product from the cutter.

19 Claims, 7 Drawing Figures PATENTEDFEBI l 1975 SHEET 10F 3 F'IG.Z

PATENHED 3.864.829

SHEET 2 OF 3 minno H915 3.864.829

SHEEI 30F 3 lllll PIC-1.7

Lllll CUTTING TOOL BACKGROUND OF THE INVENTION 1. Field of the Invention The tool has wide potential use in the cutting of product pieces from relatively thick, normally cut-resistant sheet material, for example fiberglass-impregnated sheeting, or alternatively in the excision of such material to internally shape and remove slug material therefrom. A specific instance is in the formation of aerodynamic guide vanes of fiberglass for installation in duct work or a related field; and the present disclosure is therefore addressed to that particular illustrative use, although many others will, of course, suggest themselves.

2. Description of the Prior Art A search has revealed the following patents, none of which bear with any particular pertinence on features of the improvement presently to be described:

Haas Brady Mitchell Pieper The improved tool of the invention permits a considerable mass type of production of various hard-to-cut, non-metallic sheet objects, such as the fiberglass duct vanes instanced above by a simple repetitive manipulation of the tool, involving only successive placements of the tool at appropriately spaced areas of a sheet to be excised, each followed by a depression of the tool with but moderate force to cause the tools special razor knife edge cutter to penetrate the sheet, then, upon withdrawing of the tool, to automatically eject the desired piece from the interior of the cutter. The proportioning of the latter in respect to the sheet thickness is such that a complete excision of the cutting from the sheet is completed on each operating stroke.

As herein disclosed, the cutter is a hollow one, generally crescent-shaped in horizontal cross section through its interior, as the latter is defined by generally similar lune-contoured cutter edges or blades; and the invention in a secondary detail deals with a positional relationship of extreme end edges of said blades such as to avoid feather edges on the excised piece which might obstruct its automatic ejection from the cutter by the kick-out or stripper unit which is preferably associated with the cutter proper as an adjunct of the tool.

As thus consituted of special cutter blade components, the tool has a special cutter or blade-mounting base, constituted by molded transparent Lucite blocks each shaped to mate accurately with an exposed cutter surface, and to brace and support the cutter components rigidly for their action. The transparency of said components is a great convenience to an operator in manually manipulating the tool repeatedly and at a high rate of production of excised pieces.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary top plan view of the tool and stripper assembly of the invention, including cutter, cutter mounting base structure, kick-out or stripper unit and a portion of the tools manipulating end hand pieces;

FIG. 2 is a bottom perspective view of the cutter subassembly, the stripper unit having been omitted for clarity;

FIG. 3 is a fragmentary view in transverse vertical section on line 33 of FIG. 1, indicating certain dimensional and positional relationships of cutter and stripper components, as at the completion of a productexcising operation on an excised sheet;

FIG. 4 is a view in transverse vertical section on broken line 4-4 of FIG. 1, showing details of attachment of the cutter to mounting base block components;

FIG. 5 is a fragmentary view in horizontal section on line 5-5 of FIG. 4, showing a detail of the blade and stripper relationship;

FIG. 6 is a view in vertical section on a line corresponding to line 66 of FIG. 1, illustrating the tool in the position of its parts at the commencement of a product-excising translational stroke; and

FIG. 7 is a view sectioned similarly to FIG. 6, but showing the tool at the completion of an excision operation, prior to lifting of the tool and automatic ejection of the cut piece by the stripping unit of the tool.

DESCRIPTION OF A PREFERRED EMBODIMENT FIGS. 1 and 2 best show the tool of the invention, generally designated 10, to comprise an elongated rectangular transparent tool-supporting base 11 composed ofa pair of coating block-

like members

12 and 13, each formed of the transparent methyl methacrylate material known as Lucite, or in the alternative, members of glass or an equivalent plastic may be employed. They are typically of, say, /8 inch thickness, 8 inch length and, as assembled to form the composite base 11, they aggregate approximately 3 inches in front-to-rear width, as assembled to the fiberglass piece or partexcising cutter which they rigidly mount, said cutter being generally designated by the reference numeral 14. Inasmuch as that cutter determines the contours of a pair of mutually facing upright surfaces l5, 16 of the respective

base block members

12, 13, a description in detail of the cutter 14 is here in order.

It in turn is in the form of a pair of hardened steel cutter blades l8, 19, which will respectively face the base block surfaces l5, l6; and blades l8, 19 are ofa generally similar lunate arcuate outline, although formed on different radii of curvature. Thus, blade 15 may typically be formed on a radius of 2-13/16 inches, while the milder arced blade 16 would have a radius of, say 3-1 1/16 inches. They have a common overall height, in the direction from which they project from block 11 of approximately 1- /2 inches, and as their unsharpened edges come flush with the top of mounting base 11, their sharpened razor edges 20 will project and terminate "Vs inch beneath the bottom of block 11. This typically will be a trifle less than the thickness of a sheet S (FIGS. 6 and 7) of the glass fiber matting or padding from which a vane piece or part P is excised; but allowing for the compressibility of this material under the downward thrust of tool 10, the operation is one of totally slicing through sheet S and wholly excising the piece P therefrom in a clean and precise peripheral outline.

To this end, the cutter blade edges 20 are precision ground and razor-sharpened, enabling a slicing penetration of the cut-resistant sheet S to be accomplished with a minimum of manual effort on the part of the operator. Typically, in a cutter assembly such as that herein shown, the horizontal straight line length of cutter 14 from end to end of its crescent or lunate length will be in the order of 5- /1 inches.

Reference should be had in particular to FIG. 5 in conjunction with the other figures in regard to more specific details and the relationship of the cutter blades l8, 19. These will each be, say, of a thickness of 0.0156 inch; and the blade 19 is continuous end to end in its plain arcuate contour on the 2-13/16 inch radius mentioned above, and is preferably sharpened at its oppo site upright ends 22. On the other hand, the second blade 18, although continuously contoured on its abovedescribed radius over by far the major portion of its length, is at its end extremities angled at 45 toward blade 19 and sharpened at 23 along this angle to provide a knife edge coming very close to if not contacting the terminus of the knife edge 22 of blade 19. The specifically designated

sharpenings

22, 23 are of course continuations of the major blade sharpenings at 20. There is thus defined an overall crescent-shaped cross section of the cutter 14 in a horizontal plane at 90 to the upright blades l8, 19 which, as defined at its meeting sharpened ends, produces a clean slicing cut through the sheet S without possibility of tear raggedness and without likelihood of the latter clogging the hollow interior of cutter 14, hence impeding the desired clean and positive ejection of the incised piece P from the cutter by the kick-out or stripper unit of the invention, later described in detail.

As shown in FIGS. 1, 2 and 4, the

blades

18, 19 are rigidly mounted to blocks 12 at the latters mutually facing surfaces by pairs of flat-head screws 24 threaded into tapped openings in said blocks, with the screw-heads coming flush with the opposite inner surfaces of the blades.

In conformity with the arcuate contours of the blades l8, 19 as described above, the mounting Lucite blocks l2, 13 are specially shaped at the respective mutually facing

surfaces

15, 16 thereof mentioned above. Thus, the block 12 presents its concave facing surface 15 in flush mating and clamping engagement with the lune blade component 18, and the other block 13 presents its convex face 16 in similar mating and clamping engagement with the concavity of blade 19.

As extended beyond the thus-defined, crescentshaped outline of blade 14, the

mounting blocks

12 and 13 have flush contacting engagement with one another along a horizontal upright interface zone 25, which extends the full remaining longitudinal dimension of said blocks; and a pair of horizontal elongated studs 26, as received in counterbored holes through block 12 and threaded into the block 13 through the meeting interface 25, rigidly clamp the blocks together in their own corresponding rigid clamping engagement with

cutter blades

18 and 19. Studs 26 are preferably of the Allenhead type, coming flush with the front upright surface of base mounting block 12.

Cutter base 11 is completed adjacent its opposite longitudinally spaced ends by a pair of like hand grips 28. These may be ofa l6-gauge sheet steel, flat at the inner portions thereof and secured from above to Lucite base block 12 by a set of flat head screws 29 taking threadedly into the material of said block. Otherwise, the hand grips 28 are rolled at 30 along portions thereof which project upwardly and outwardly from the fiat screwed portion thereof for a convenient and comfortable grip by an operataor in manipulating the tool.

FIGS. 3, 6 and 7 best shown, as optionally assembled to the cutter sub-assembly mentioned above, a kick-out or stripper unit or sub-assembly, generally designated 32. It comprises a pair of upright guide pins, rods or posts 33, which may be in the form of elongated machine bolts or studs. These project well upwardly above the top of cutter mounting base 11, and are rigidly fixed at their lower ends to the mounting block 12, as at lower stud ends threaded or otherwise mounted fast in upright holes 34 in block 12. As appears in FIG. 1, the stud rods 33 are located outwardly to either side of the crescent zone occupied in mounting base 11 by the cutholes in the guide bar 35, and being fixedly secured to said bar by nuts 41 threaded on the screws from beneath and from above said bar.

Stripper plate 40 is conformed to correspond with the cross sectional hollow interior area of cutter 14, but, of course, of somewhat lesser perimeter to enable a vertical relative shift of plate 40 within the cutter in its initial engagment with the sheet S and its ultimate action in expelling piece or part P from the cutter. In its inoperative and fully downwardly extended position, the stripper 40 comes horizontally flush with the sharpened razor edges 20 of the cutter.

In use, with the fiberglass sheet S to be cut appropriately laid out on a suitable rigid base B (FIGS. 6 and 7) the combined tool 10 is held by the hand grips 30 and placed atop the sheet, as depicted in FIG. 6, with the kick-out plate 40 and cutter knife edge formations 20 disposed coplanar and in engagement with the top surface of the sheet. The operator now applies a steady downward force on the tool until the cutter blade 14 engages fully downwardly upon base B, as appears in FIG. 7, the mounting base 12 and cutter compressing the sheet to some extent as the excision of vane part P is completed.

FIG. 7 shows that the stripper plate 40 rises in the interior of blade 14 as this takes place. The operator then lifts tool 10, preferably exerting a degree of upward sustaining force on the guide bar 35, sufficient to hold stripper plate 40 in its position relative to blade 14 shown in FIG. 7, until the tool is cleared from sheet S. He will then release the guide bar 32, whereupon the compressed coil springs 36 will operate the bar to expell the part P from the cutter.

This procedure may be repeated at a high rate of production speed, the transparency of the Lucite base 11 greatly assisting the operator in positioning the tool for successive lunate cuts in close adjacency to one another on sheet S. This, of course, conserves material and reduces its cost.

What is claimed is:

l. A cutting tool comprising a rigid base fixedly supporting a cutter for an excising operation on a sheetlike object, said cutter presenting a knife edge defined by two knife edge portions of generally similar lunate contour, said knife edge being exposed well to a side of said base and shaped in the outline of an area on said object which is excised from the latter by the tool, said base having a lunate-shaped opening presenting mutually facing surfaces respectively shaped to complement and mate with opposite outwardly facing surfaces of said knife edge portions which partly extend into said lunate-shaped opening, which mutually facing surfaces of said opening have fixed mating and holding engagement with the respective outwardly facing surfaces of said knife edge portions, 21 stripping unit mounted on said base to act from the latters side opposite that on which said knife edge portions are exposed, said unit comprising a stripping member of lunate-shaped outline slidably movable between and relative to said knife edge portions in engagement with said object area during excision of the latter, rod means fixed on said base and extending from said opposite base side, and a guide piece spaced from and fixed on said stripping member and guided on said rod means in said movement of said stripping member.

2. A cutting tool comprising a rigid base fixedly supporting a cutter for an excising operation on a sheet like object, said cutter presenting a knife edge exposed well to a side of said base and shaped in the outline of an area on said object which is excised from the latter by the tool, said base presenting mutually facing surfaces respectively shaped to complement and mate with opposite outwardly facing surfaces of said cutter knife edge, which mutually facing surfaces of the base have fixed mating and holding engagement with the respective outwardly facing surfaces of said knife edge, and a stripping unit mounted on said base to act from the latters side opposite that on which said knife edge is exposed, said unit comprising a stripping member conformed in a general outline of the excised object and slidably movable within and relative to said cutter in engagement with said object during excision of the latter, and spring means acting between said base and said stripping member in resiliently opposing said relative motion of the latter concurrently with the excising operation of said cutter, said spring means returnbiasing the stripping member after excision of the object to expel the latter from within the cutter.

3. The cutting tool of claim 2, in which said base is transparent for viewing of the object and excised area by a user of the tool.

4. The combination of claim 2, in which said base comprises a pair of base members presenting said mutually facing surfaces, said base members are ofa lighttransmitting material.

5. The combination of claim 2, in which said base comprises a pair of base members presenting said mutually facing surfaces, said base members are of a lighttransmitting material and the base is equipped with handle means corresponding which it and the cutter are manipulated in the excising operation.

6. The combination of claim 2, in which said knife edge of the cutter includes a pair of knife edge portions of generally similar arcuate contour spaced laterally from one another in a generally nested relation of correspopnding convexities of said portions as supported between said mutually facing base member surfaces.

7. A cutting tool comprising a rigid base fixedly supporting a cutter for an excising operation on a sheetlike object, said cutter presenting a knive edge exposed well to a side of said base and shaped in the outline of an area on said object which is excised from the latter by the too], said base comprising a pair of members presenting mutually facing surfaces respectively shaped to complement and mate with opposite outwardly fac ing surfaces of said cutter knife edge, which mutually facing surfaces of the base members have fixed mating and holding engagement with the respective outwardly facing surfaces of said knife edge, said knife edge of the cutter being defined by at least two knife edge portions each matingly engaged and held at a shaped facing surface of a base member, and a stripping unit mounted on said base to act from the latter's side opposite that on which said knife edge is exposed, said unit comprising a stripping member conformed in the general outline of the excised object and slidably movable between and relative to said cutter members in engagement with said object area during excision of the latter, rod means fixed on said base and extending from said opposite base side, a guide piece fixed on said stripping member and guided on said rod means in said movement of the stripping member, and coil compression spring means surrounding said rod means and acting on said guide piece in resiliently opposing motion of said piece and the stripping member concurrently with the excising operation of said cutter, said spring means returnbiasing the stripping member after excision of the object to expel the latter from within the cutter.

8. The cutting tool of claim 7, in which said base members are transparent for viewing of the object and excised area by a user of the tool.

9. The combination of claim 7, in which said base members are of a light-transmitting material.

10. The combination of claim 7, in which said base members are of a light-transmitting material and the base is equipped with handle means by which it and the cutter are manipulated in the excising operation.

11. The cutting tool of claim 7, in which said knife edge portions are of generally similar arcuate contour spaced laterally from one another in a generally nested relation of corresponding convexities of said portions as supported between said mutually facing base member surfaces.

12. The cutting tool of claim 7, in which said knife edge portions are of generally similar arcuate contour spaced laterally from one another in a generally nested relation of corresponding convexities of said portions as supported between said mutually facing of said base members, said knife edge portions terminating in a close relation to one another at adjacent ends of said arcuate contours thereof.

13. The cutting tool of claim 12, in which said knife edge portions are of lunate contour, the terminals thereof nevertheless defining an extreme terminal portion of the excised object which has appreciable width in the plane of the object.

14. A cutting tool comprising a rigid base having a pair of generally parallel sides, said base fixedly supporting a cutter for an excising operation on a sheetlike object, said cutter presenting a knife edge exposed well to one of said sides of said base and shaped in the outline of an area on said object which is excised from the latter by the tool, said base having a cavity presenting a pair of mutually facing surfaces respectively shaped to complement and mate with opposite outwardly facing surfaces of said cutter knife edge which extend into said cavity, said mutually facing surfaces of said base having fixed mating and holding engagement with the respective outwardly facing surfaces of said knife edge, and a stripping unit mounted on said base to act from the other of said sides of said base opposite said one side on which said knife edge is exposed, said unit comprising a stripping member conformed in a general outline of the excised object and slidably movable within and relative to said cutter in engagement with said object during excision of the latter, an elongated guide piece on said other side of said base, fastening means connecting said guide piece to said stripping member to maintain said guide piece and said stripping member in spaced relation, and a pair of spaced apart guide posts on said other side of said base, said guide posts having end portions carried by said base, said guide posts extending through openings provided in opposite end portions of said guide piece, said guide piece being guided on said guide posts in said movement of said stripping member during and after the excising operation of said cutter.

15. The cutting tool defined in claim 14 wherein said fastening means is adjustable to vary the spacing between said guide piece and said stripping member.

16. The cutting tool defined in claim 15 wherein said fastening means comprises a pair of nut and bolt type fasteners, each bolt having a head engageable with one surface of the stripping member and a threaded stem extending through openings in said base and in said guide piece, with threaded nuts on the bolt on opposite sides of said guide piece to maintain said guide piece and said stripping member in said spaced relation.

17. The cutting tool defined in claim 14 wherein said guide posts are in the form of elongated bolts threaded to said base.

18. The cutting tool defined in claim 14 wherein means are provided on said base for returning said stripping unit after said excising operation to a position with said stripping member adjacent said one side of said base.

19. A cutting tool comprising a rigid base having a pair of generally parallel sides, said base fixedly supporting a cutter for an excising operation on a sheetlike object, said cutter precenting a knife edge defined by two knife edge portions of generally lunate contour, said knife edge portions being exposed well to one of said sides of said base and shaped in the outline of an area on said object which is excised from the latter by the tool, said base having a lunate shaped opening presenting a pair of mutually facing surfaces respectively shaped to complement and mate with opposite outwardly facing surfaces of said knife edge portions which extend into said opening, said mutually facing surfaces of said base having fixed mating and holding engagement with the respective outwardly facing surfaces of said knife edge, said knife edge portions terminating in a close relation to one another at adjacent ends of said lunate contours thereof, the terminals of said knife edge portions defining an extreme terminal portion of the excised object which has appreciable width in the plane of the object, and a stripping unit mounted on said base to act from the other of said sides of said base opposite said one side on which said knife edge is exposed, said unit comprising a stripping member of lunate shape conformed in a general outline of the excised object and slidably movable within and relative to said cutter in engagement with said object during excision of the latter, an elongated guide piece on said other side of said base, fastening means connecting said guide piece to said stripping member to maintain said guide piece and said stripping member in spaced relation, and a pair of spaced apart guide posts on said other side of said base, said guide posts having end portions carried by said base, said guide posts extending through openings provided in opposite end portions of said guide piece, said guide piece being guided on said posts in said movement of said stripping member during and after the excising operation of said cutter.

Claims

1. A cutting tool comprising a rigid base fixedly supporting a cutter for an excising operation on a sheet-like object, said cutter presenting a knife edge defined by two knife edge portions of generally similar lunate contour, said knife edge being exposed well to a side of said base and shaped in the outline of an area on said object which is excised from the latter by the tool, said base having a lunate-shaped opening presenting mutUally facing surfaces respectively shaped to complement and mate with opposite outwardly facing surfaces of said knife edge portions which partly extend into said lunate-shaped opening, which mutually facing surfaces of said opening have fixed mating and holding engagement with the respective outwardly facing surfaces of said knife edge portions, a stripping unit mounted on said base to act from the latter''s side opposite that on which said knife edge portions are exposed, said unit comprising a stripping member of lunate-shaped outline slidably movable between and relative to said knife edge portions in engagement with said object area during excision of the latter, rod means fixed on said base and extending from said opposite base side, and a guide piece spaced from and fixed on said stripping member and guided on said rod means in said movement of said stripping member.

2. A cutting tool comprising a rigid base fixedly supporting a cutter for an excising operation on a sheet-like object, said cutter presenting a knife edge exposed well to a side of said base and shaped in the outline of an area on said object which is excised from the latter by the tool, said base presenting mutually facing surfaces respectively shaped to complement and mate with opposite outwardly facing surfaces of said cutter knife edge, which mutually facing surfaces of the base have fixed mating and holding engagement with the respective outwardly facing surfaces of said knife edge, and a stripping unit mounted on said base to act from the latter''s side opposite that on which said knife edge is exposed, said unit comprising a stripping member conformed in a general outline of the excised object and slidably movable within and relative to said cutter in engagement with said object during excision of the latter, and spring means acting between said base and said stripping member in resiliently opposing said relative motion of the latter concurrently with the excising operation of said cutter, said spring means return-biasing the stripping member after excision of the object to expel the latter from within the cutter.

4. The combination of claim 2, in which said base comprises a pair of base members presenting said mutually facing surfaces, said base members are of a light-transmitting material.

5. The combination of claim 2, in which said base comprises a pair of base members presenting said mutually facing surfaces, said base members are of a light-transmitting material and the base is equipped with handle means corresponding which it and the cutter are manipulated in the excising operation.

7. A cutting tool comprising a rigid base fixedly supporting a cutter for an excising operation on a sheet-like object, said cutter presenting a knive edge exposed well to a side of said base and shaped in the outline of an area on said object which is excised from the latter by the tool, said base comprising a pair of members presenting mutually facing surfaces respectively shaped to complement and mate with opposite outwardly facing surfaces of said cutter knife edge, which mutually facing surfaces of the base members have fixed mating and holding engagement with the respective outwardly facing surfaces of said knife edge, said knife edge of the cutter being defined by at least two knife edge portions each matingly engaged and held at a shaped facing surface of a base member, and a stripping unit mounted on said base to act from the latter''s side opposite that on which said knife edge is exposed, said unit comprising a stripping member conformEd in the general outline of the excised object and slidably movable between and relative to said cutter members in engagement with said object area during excision of the latter, rod means fixed on said base and extending from said opposite base side, a guide piece fixed on said stripping member and guided on said rod means in said movement of the stripping member, and coil compression spring means surrounding said rod means and acting on said guide piece in resiliently opposing motion of said piece and the stripping member concurrently with the excising operation of said cutter, said spring means return-biasing the stripping member after excision of the object to expel the latter from within the cutter.

14. A cutting tool comprising a rigid base having a pair of generally parallel sides, said base fixedly supporting a cutter for an excising operation on a sheet-like object, said cutter presenting a knife edge exposed well to one of said sides of said base and shaped in the outline of an area on said object which is excised from the latter by the tool, said base having a cavity presenting a pair of mutually facing surfaces respectively shaped to complement and mate with opposite outwardly facing surfaces of said cutter knife edge which extend into said cavity, said mutually facing surfaces of said base having fixed mating and holding engagement with the respective outwardly facing surfaces of said knife edge, and a stripping unit mounted on said base to act from the other of said sides of said base opposite said one side on which said knife edge is exposed, said unit comprising a stripping member conformed in a general outline of the excised object and slidably movable within and relative to said cutter in engagement with said object during excision of the latter, an elongated guide piece on said other side of said base, fastening means connecting said guide piece to said stripping member to maintain said guide piece and said stripping member in spaced relation, and a pair of spaced apart guide posts on said other side of said base, said guide posts having end portions carried by said base, said guide posts extending through openings provided in opposite end portions of said guide piece, said guide piece being guided on said guide posts in said movement of said stripping member during and after the excising operation of said cutter.

19. A cutting tool comprising a rigid base having a pair of generally parallel sides, said base fixedly supporting a cutter for an excising operation on a sheet-like object, said cutter precenting a knife edge defined by two knife edge portions of generally lunate contour, said knife edge portions being exposed well to one of said sides of said base and shaped in the outline of an area on said object which is excised from the latter by the tool, said base having a lunate shaped opening presenting a pair of mutually facing surfaces respectively shaped to complement and mate with opposite outwardly facing surfaces of said knife edge portions which extend into said opening, said mutually facing surfaces of said base having fixed mating and holding engagement with the respective outwardly facing surfaces of said knife edge, said knife edge portions terminating in a close relation to one another at adjacent ends of said lunate contours thereof, the terminals of said knife edge portions defining an extreme terminal portion of the excised object which has appreciable width in the plane of the object, and a stripping unit mounted on said base to act from the other of said sides of said base opposite said one side on which said knife edge is exposed, said unit comprising a stripping member of lunate shape conformed in a general outline of the excised object and slidably movable within and relative to said cutter in engagement with said object during excision of the latter, an elongated guide piece on said other side of said base, fastening means connecting said guide piece to said stripping member to maintain said guide piece and said stripping member in spaced relation, and a pair of spaced apart guide posts on said other side of said base, said guide posts having end portions carried by said base, said guide posts extending through openings provided in opposite end portions of said guide piece, said guide piece being guided on said posts in said movement of said stripping member during and after the excising operation of said cutter.