US3719113A

US3719113A - Penetrable bed used for cutting sheet material and method for treating same

Info

Publication number: US3719113A
Application number: US00094882A
Authority: US
Inventors: H Gerber; D Pearl
Original assignee: Gerber Garment Technology Inc
Current assignee: Gerber Technology LLC
Priority date: 1970-12-03
Filing date: 1970-12-03
Publication date: 1973-03-06
Anticipated expiration: 1990-03-06
Also published as: FR2114425A5; GB1337821A; DE2144852A1

Abstract

A bed of material provides a supporting surface for supporting sheet material during a cutting process. The bed is used in combination with a cutting apparatus having a cutter and a means for moving the cutter and the bed with respect to each other. The supporting surface is penetrated and cut during the sheet material cutting operation. At least the top layer of the bed material is of such a nature that it may be restored to a substantially uncut or healed condition after having been penetrated and cut to the point where its capacity for properly supporting sheet material is impaired. This restoration may be accomplished by subjecting the bed material to a restoring influence such as heat, ultrasonic waves, or a solvent, or by bonding a thin sheet of plastic or other sheet material to the supporting surface. Particular apparatus combinations are disclosed which will apply the desired restoring mediums at the desired time.

Description

United States Patent 91 Gerber et a1.

[ 1 March 6, 1973 [54] PENETRABLE BED USED FOR CUTTING SHEET MATERIAL AND METHOD FOR TREATING SAME [73] Assignee: Gerber Garment Technology, Inc.,

East Hartford, Conn.

[22] Filed: Dec. 3, 1970 [2]] Appl. No.: 94,882

[52] U.S. Cl. ..83/56, 83/169, 83/170, 83/174, 83/658, 83/701, 83/925 CC [51] Int. Cl ..B26d 7/08, B26d 7/10 [58] Field of Search .83/171, 174, 658, 659, 925 CC, 83/13, 49, 56,169,170, 701; 156/81, 250

FOREIGN PATENTS OR APPLICATIONS 840,211 l/1939 France ..83/658 Primary ExaminerJ. M. Meister AttorneyMcCormick, Paulding & Huber 5 7 ABSTRACT A bed of material provides a supporting surface for supporting sheet material during a cutting process. The bed is used in combination with a cutting apparatus having a cutter and a means for moving the cutter and the bed with respect to each other. The supporting surface is penetrated and cut during the sheet material cutting operation. At least the top layer of the bed material is of such a nature that it may be restored to a substantially uncut or healed condition after having been penetrated and cut to the point where its capacity for properly supporting sheet material is impaired. This restoration may be accomplished by subjecting the bed material to a restoring influence such as heat, ultrasonic waves, or a solvent, or by bonding a thin sheet of plastic or other sheet material to the supporting surface. Particular apparatus combinations are disclosed which will apply the desired restoring mediums at the desired time.

17 Claims, 9 Drawing Figures PATENTED 51973 SHEET 1 BF 3 INVENTORS HE lNZ JOSEPH GERBER 0A V/D RA YMOND PEARL a p Azr ozmmrs PATENTED W 1373 SHEET 30F 3 VVVVV PENETRABLE BED USED FOR CUTTING SHEET MATERIAL AND METHOD FOR TREATING SAME RELATED APPLICATION This application is related to subject matter disclosed in the copending US. application, Ser. No. 821,723, filed May 5, 1969.

BACKGROUND OF THE INVENTION This invention relates to devices for cutting sheet material such as garment and upholstery materials and the like, and deals more particularly with a penetrable bed providing a supporting surface for sheet material to be cut and the means and methods for treating such a bed to periodically restore it to an improved condition.

The general object of this invention is to provide a supporting surface for supporting sheet material being cut by a knife or similar cutting tool and which supporting surface is provided by a bed of material capable of being penetrated by the cutting tool during the cutting process and capable of thereafter being treated to restore the supporting surface to a substantially uncut or healed condition so as to eliminate the necessity of replacing the bed after it becomes excessively used or worn.

It is another object of this invention to provide a means for effecting the restoration of the supporting surface while the bed material is in place relative to the remainder of the cutting apparatus and which is otherwise simple and easy to use.

Another object of this invention is to provide a bed of material defining a supporting surface, the top surface layer portion of which may be restored through the application of common easily applied and inexpensive mediums such as heat, ultrasonic waves or solvent material.

A further object of this invention is to provide methods for restoring the top surface layer of a penetrable bed after the bed has been used as a support means during the cutting of sheet material.

Other objects of this invention will appear in the following description and appended claims, reference being made to the accompanying drawings forming a part of the specification wherein like reference characters designate corresponding parts in the several views.

SUMMARY OF THE INVENTION A penetrable bed of material having a restorable top supporting surface is used in combination with a sheet material cutting apparatus having a cutter with a cutting tool such as a reciprocating knife which penetrates and cuts the supporting surface during the cutting process. After the bed has been used throughout a series of cutting procedures, the supporting surface may be restored for further use by applying various types of restoring mediums thereto.

Specific embodiments of this invention include the use of thermoplastic material, in at least the top layer of the bed, which may be restored through the application of heat. The top layer of the bed may also be composed of a solvent soluble material which may be restored by application of a suitable solvent material thereon. Material which is subject to change by ultrasonic waves may also be used for forming the top layer of the bed. Also a sheet of thin penetrable plastic or other sheet material may be bonded by adhesive or heat to the supporting surface to effect its restoration.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a fragmentary perspective view of a sheet material cutting apparatus made in accordance with this invention;

FIG. 2 is an enlarged sectional view taken along line 2-1 of FIG. 1;

FIG. 3 is an enlarged, fragmentary sectional view taken along line 3-3 of FIG. 1;

FIG. 4 is an enlarged fragmentary side elevational view of the apparatus of FIG. 1 shown partially in section;

FIG. 5 is a view generally similar to FIG. 3 showing a further embodiment of the invention;

FIG. 6 is a view generally similar to FIG. 3 showing a further embodiment of the invention;

FIG. 7 is a view generally similar to FIG. 1 showing another embodiment of the invention;

FIG. 8 is a view generally similar to FIG. 1 showing a still further embodiment of the invention; and

FIG. 9 is a view generally similar to FIG. 2 but shows a further apparatus made in accordance with this in-, vention.

DESCRIPTION OF SPECIFIC EMBODIMENTS FIGS. 1 to 4 show one form of apparatus embodying the present invention. Referring more specifically to these FIGS, a sheet material or fabric cutting apparatus, generally designated 10, includes a table 11 having a bed of material 17 which provides a supporting surface 20 for a fabric layup 12 consisting of a plurality of fabric sheets arranged in vertically stacked relation. A work carriage, generally designated 13, is adapted to move above and parallel to the surface of the table 11 in the coordinate directions indicated by the arrows X and Y. A cutter 15 having a reciprocating cutting blade 16 is mounted on the carriage 13 so that it can be driven to and from any predetermined point on the table surface and along any desired line of cut relative to the fabric layup 12. The blade 16 extends downwardly from the main body of the cutter l5 and is reciprocated vertically by a motor in the cutter body. It may also be rotated about a vertical 0 axis by another motor in the cutter body for the purpose of maintaining the blade tangent to the line of cut. The cutter may also be raised and lowered bodily, by another motor, to move the cutting blade out of and into cutting engagement with the fabric layup, FIG. 1 showing the cutter in its lowered position at which the blade is in cutting engagement with the fabric.

A main carriage 25 is movably mounted on

racks

14, 14, thereby providing movement for the cutter along the longitudinal dimension of table 11 or in the X coordinate direction. The work carriage 13 is movably mounted on a guide bar or tube 26 and a lead screw 34, of the main carriage 25, which extend transversely of the table 11. Movement of the carriage 13 along the guide bar 26, as driven by the lead screw 34, is in the Y coordinate direction.

The main carriage 25 includes a drive shaft (not shown) which extends transversely of the table 11 and which has pinions at its opposite ends for engaging the

racks

14, 14. Movement of the main carriage 25 is cf fected in response to operation of a drive motor (not shown) which is connected to the main carriage drive shaft. The work carriage 13 moves transversely of the table in response to the operation of another guide motor (not shown) which is operably connected to the lead screw 34.

The movement of the carriages 13 and 25 may be effected in response to positioning signals supplied through the cable 24 by an associated input means such as, for example, a numerically controlled controller or a computer (not shown). THe carriages 13 and 25 are capable of moving the blade 16 is cutting engagement with the layup 12 along any line which may be straight or curved as required in cutting a garment component or the like. When in cutting engagement with the fabric layup, the blade 16 during at least a portion of its stroke penetratesthe upper supporting surface 20 of the table 11. Except for the construction of the bed 17 and the means for periodically restoring its supporting surface 20, as hereinafter described, the construction and operation of the cutting apparatus is or may be similar to that described in copending application, Ser. No. 821,723, filed May 5, 1969, to which reference may be made for further details.

The invention of this particular application is directed specifically to the use of a penetrable bed 17 i in the table 11 having a restorable supporting surface 20, and to means and methods for effecting such restoration. In the table 11 of FIG. 1, the bed 17 is disposed in a frame having a bottom wall 22 and side and end walls (not numbered) which extend upwardly from the bottom wall 22 to form a shallow container. The bed 17 may, if desired, be formed from a plurality of generally rectangular blocks, the broken lines in FIG. 1 indicating the boundaries of such blocks.

The bed 17 of FIG. 1 is one which is constructed so as to enable its supporting surface to be restored by means of heat. In particular, the illustrated bed 17 includes a base portion 19, a body portion 18 made of a material readily penetrable by the blade 16, and a top thin layer or skin 21 made of a thermoplastic material having a relatively low melting point. The material from which the layer 21 is made is one which when applied as a thin layer or skin to the body portion 18 is readily penetrable by the knife blade 16 even though it may not be readily penetrable by the blade if formed into thicker sheets or blocks. In FIGS. 1 to 4 the thickness of the layer 21 is exaggerated for purposes of clarity and it should be understood that, depending on the material used for forming this layer, its thickness is sufficiently small that it may be readily penetrated with ease by the knife blade. Various different low melting point resins and plastics may be used to form this layer. The material of the body portion 18 may be any one of various different materials which are capable of providing the bed 17 with some depth, to accommodate the portion of the knife blade which extends below the supporting surface 20, and through which the blade may pass with comparative ease. In the illustrated case this material is taken to be felt made of relatively loosely compacted fibers and formed into blocks or strips which blocks or strips are arranged on end and attached by glue to the base 19. As an alternative the body portion 18 may be made of a cellular plastic material having a substantially higher melting point than the melting point of the material of which the top layer 21 is made. In FIG. 1 the base portion 19 is used to hold in assembly the individual strips or blocks of felt of the body portion 18, and in cases where the body portion 18 is made of larger individual pieces of material, the base portion 19 may be omitted.

As mentioned above, in the specific embodiment disclosed in FIGS. 1 to 4, the body portion 18 of the bed 17 is composed of relatively loosely constituted felt and has a coating or layer 21 of thermoplastic material on its upper surface and defining the supporting surface 20 of the bed. Actually, the thermoplastic material in making the bed 17 is applied to the felt body portion in a melted state and may actually be absorbed by the top portion of the felt body 18 so that the restorable surface layer or skin 21 becomes a composite structure made of the felt fibers and the thermoplastic material. In any event, the top surface layer 21 of the bed is penetrated by the knife blade 16, as shown in FIGS. 2 and 4 during a cutting operation, and after the performance of many cutting operations the upper portion of the bed 17 may become so cut up along closely adjacent and intersecting lines that the bed no longer presents to the layup a continuous firm supporting surface but instead forms a surface divided into many separate discrete portions which are capable of moving and deforming relative to one another and which thereby allow the fabric of the layup to shift and deform in an undesirable manner as'it is being cut. Once the bed 17 reaches such a state that it no longer provides desirable support for the material or cloth being cut, the upper layer or skin 21 is subjected to heat to melt or soften the thermoplastic material making up such layer and to refuse together the previously cut portions of such layer to again form a continuous firm surface.

The means by which heat is applied to the bed 17 to melt or soften the thermoplastic material of the layer 21 may take various different forms without departing from the broader aspects of this invention. In the embodiment of FIGS. 1 to 4, this means comprises a plurality of

heat lamps

30, 30 which are carried bya bar 29 attached to the main carriage 28 and extending transversely of the table 11. The

heat lamps

30, 30 are disposed with their output faces directed toward and spaced some distance from the supporting surface 20 and when it is desired to restore the supporting surface 20 these lamps are turned on and the carriage 28 is slowly moved from one end to the other of the table 1 1. By properly selecting the rate of movement of the carriage 28 during this process, the heat lamps may be caused to heat the upper portion 20 of the bed to the optimum degree required to weld or refuse together the cut portions of the surface 21 and to restore it to its original condition as existing before any cutting had taken place.

In the apparatus of FIG. 1, the

heat lamps

30, 30 are, as mentioned, attached to the main carriage 28 for movement therewith. Since these heat lamps are used only infrequently to restore the supporting surface 20, they may, if desired, be mounted on another carriage separate from the main carriage 25, and this separate carriage for the heat lamps may, if desired, be a relatively simple carriage designed to be moved along the length of the table 11 by hand. It may also be designed for easy attachment to and removal from the table 11 so as to enable it to be attached to the table only when needed to restore the supporting surface and to enable its use with a number of individual tables. It will of course be understood that in place of

heat lamps

30, 30 various other heating means may be employed, such as electrical resistance heating units.

In addition to the use of heat for restoring a bed having a thermoplastic upper surface layer, various other different means and methods may be used for restoring the supporting surface of a sheet material cutting device in accordance with this invention. FIG. 5, for example, shows a device in which the supporting surface is restored by spraying a solvent onto it. Referring to this FIG., the illustrated bed 17a is substantially similar to the bed 17 of FIG. 1 except for including, in place of the thermoplastic upper layer or skin 21 of FIG. 1, and upper layer or skin 34 made of a material which is readily soluble by a suitable solvent. The remainder of the bed 170 may include a body portion 18 similar to the body portion 18 of FIG. 1 and a base 19 similar to the base 19 of FIG. 1. After the bed 17a becomes cut to an undesirable degree, restoration of the cut top surface layer 34 is effected through the use of a carriage 31 which may be part of the main carriage or a separate unit. A supply of solvent material is applied to the carriage 31 and is applied to the top surface layer 34 of the bed 17a through a plurality of

nozzles

33, 33 disposed along a conduit 34 carried by the carriage 31 and extending transversely of the bed 17a. As the solvent is sprayed from the

nozzles

33, 33 the carriage 31 is moved longitudinally along the length of the table from one end to another. The solvent puts at least some of the material of the layer 34 into solution and after the solvent thereafter evaporates it leaves behind a newly reformed upper layer 34 which is restored to substantially the same condition as existed before any cutting had taken place.

FIG. 6 shows another embodiment of the invention which uses ultrasonic wave energy for restoring the top layer of the supporting bed. As shown in this FIG., the illustrated apparatus is substantially similar to that of FIG. 3 except that the penetrable bed 17b includes an upper layer 42 of material, substituted for the layer 21 of FIG. 3, which is of a type which changes its physical state from a solid or semisolid to a liquid or semiliquid in the presence of ultrasonic wave energy and which returns to its solid or semisolid state when the ultrasonic wave energy is removed. Cooperating with the bed 17b of FIG. 7 are a plurality of

ultrasonic wave generators

44, 44 carried by a support member 46 extending transversely of the bed 17b and carried by a carriage 46 for movement longitudinally of the bed. When it is desired to restore the surface of the bed 17b, the

ultrasonic wave generators

44, 44 are turned on and act to direct ultrasonic wave energy onto the surface 42, and as the generators are turned on the carriage is moved longitudinally from one end to the other of the bed 17b to treat the entire upper surface of the bed. It will be understood that as the material of the top surface receives the ultrasonic wave energy it is transformed temporarily to a liquid or semiliquid state which causes the cut areas thereof to flow together and after the receipt of the wave energy is terminated the material resolidifies to refuse the surface into a single continuous form.

In addition to restoring the supporting surface of a penetrable bed by treating the upper surface layer of the material of such bed, the supporting surface may also be restored by adding to the supporting surface new material which bonds together the cut portions of the bed and which itself forms a new surface. One method and apparatus for effecting restoration in this manner is shown by way of example in FIG. 7. Referring to this FIG., a table is shown at 50 and includes a bed of penetrable material 52 which is taken to be a cellular foamed plastic such as Ethofoam, but which could also take various other different forms of easily penetrated material such as loosely compacted felt. The lines indicated at 54, 54 represent previous lines of cut made in and through the original supporting surface 56 of the bed 52. In order to restore the cut supporting surface 56, a thin sheet 58 of thermoplastic material is spread over the surface 56 and is then heated to a degree sufficient to cause it to bond, after removal of the heat, to the material of the bed 52. That is, by properly controlling the heat applied to the sheet 58, it may be made to melt slightly and to a degree sufficient to cause it to weld or bond to the material of the bed 52 without destroying its continuity. Therefore, after the heat is removed, the sheet 58 in effect becomes part of the bed 52 and forms a new continuous surface for such bed. As shown in FIG. 7, the heat used to bond the sheet 52 to the bed 52 may be provided by a row of

heat lamps

60, 60 carried by the carriage 25.

In addition to the sheet 58 being made of a ther moplastic material and bonded to the bed 52 by means of heat, sheets of the same or different material as the sheet 58 may also be used and may be bonded to the surface 56 of the bed 52 by means of suitable adhesive, the adhesive first being applied to the surface 56 and the sheet thereafter being placed over the adhesive coated surface. Also, instead of using a performed sheet, a hardenable liquid, such as an epoxy resin with an appropriate catalyst, may be spread over the cut supporting surface and thereafter hardened to form a new continuous supporting surface.

In the above embodiments of the invention utilizing heat as a medium for restoring the supporting surface of the penetrable bed, the heat has been applied by localized heating means moved relative to the table. If desired, however, the heat may also be applied by various heating means built into the body of the table 11 and adapted to heat at one time the full extent of the supporting surface or at least large zones of such surface. One such apparatus is shown in FIG. 8 in which the heating of the illustrated bed 60 is effected by an electric resistance heating element 62 incorporated in the bed 60. The illustrated element 62 is in the form of a wire extending in many loops throughout the length of the bed 60 so as when it is energized it substantially uniformly heats the entire extent of the bed, the element 62 being located below the level of the maximum penetration of the knife 16. Except for the addition of the heating element 62 and the omission of the

heat lamps

30, 30, the apparatus of FIG. 8 is substantially similar to that of FIG. 1, and parts of FIG. 8 which are similar to those of FIG. 1 have been given the same reference numerals as in FIG. 1 and need not be redescribed.

In the embodiments of the invention described above the fabric layup 12 has been supported on the supporting surface 20 of the bed by principally its own weight. In many cases it may be desirable to add an additional holding influence to the layup to prevent its shifting during the cutting operation, and one very desirable means for effecting such holding influence involves the use of an air impervious sheet covering the layup and acting in conjunction with a vacuum means for evacuating the space between the air impervious sheet and the supporting surface so that atmospheric pressure acting on the outside of the air impervious sheet forces it toward the supporting surface and causes it to hold the layup in a relatively rigid condition.

This general concept of a vacuum holddown for a fabric layup is disclosed in US. Pat. No. 3,495,492 to which reference may be made for further details of such a means. As shown in this patent, the means for evacuating the space between the supporting surface and the air impervious sheet includes a vacuum chamber located below the penetrable bed and air passages extending through the bed material from the supporting surface to the vacuum chamber. In cases, such as described above, wherein the bed includes a restorable upper layer defining the supporting surface, it may be difficult to retain air passages through the bed as the surface layer is restored. Therefore, where it is desirable to use a vacuum holddown means in combination with a bed having a restorable supporting surface, the difficulty in maintaining air passages through the penetrable bed may be circumvented by designing the evacuating means so as to withdraw air from the edges of the layup rather than from the bottom of the layup and through the bed material. One arrangement for doing this is shown, by way of example, in FIG. 9.

Referring to FIG. 9, the apparatus there shown includes a table 1 la including a bed of penetrable material 17 similar to the bed 17 of FIG. 1. Below the wall 22 the table 1 la includes a vacuum chamber 39 connected to a suitable source of vacuum through a conduit 40. The upper wall 22 of the vacuum chamber extends outwardly, on both sides, beyond the longitudinal edges of the bed 17, and outboard of the bed 17, on each side, includes a number of

passages

38, 38 passing through the wall 22. Positioned above the

passages

38, 38 and extending along the length of the longitudinal edges of the bed 17 are two side blocks 37, 37 of air permeable material such as loose fibered felt or open celled foamed plastic. In FIG. 9 only a few of the

passages

38, 38 are illustrated but it should be understood that the table 11a includes a large number of such passages arranged along the full length of the table on either side thereof so that along the full length of the table the side blocks 37, 37 are subjected to the vacuum of the vacuum chamber. Each side block 37 extends upwardly beyond the supporting surface 20 of the bed 17 and into adjacent relationship to the associated longitudinal edge of the layup 12. An air impervious plastic sheet 36 is placed over the top of the layup l2 and also extends over the side blocks 37, 37 and downwardly into overlying relationship withthe side walls of the table 110. When a vacuum is applied to the vacuum chamber 39 through the conduit 40, air is withdrawn through the air

permeable blocks

37, 37 and through the

passages

38, 38 to evacuate the space between the supporting surface 20 and the air impervious plastic sheet 36 with the result that atmospheric pressure acting on the top of the sheet presses it downwardly toward the supporting surface to holdthe material of the layup firmly in place. It is here assumed that the material of the layup 12 is relatively air permeable so that when vacuum is applied to the vacuum chamber the air trapped in the layup may be withdrawn laterally through the material of the layup. In cases where the material of the layup consists of relatively air impervious sheets, such as sheets of plastic, an air conducting means such as a sheet of cor-- rugated cardboard or a sheet of air permeable material may be sandwiched between the air impervious plastic sheet 36 and the top surface of the layup 12 to permit evacuation of the space therebetween and to achieve the desired holddown by atmospheric pressure.

We claim:

1. In a sheet material cutting apparatus the combination comprising means providing a supporting surface for supporting in a spread condition sheet material to be cut, a cutter having a cutting tool, and means for supporting and moving said cutter and said supporting surface relative to one another in such a manner that during a cutting operation said cutting tool passes through and cuts the material on said supporting surface and penetrates said supporting surface and so that said cutting tool is movable relative to said supporting surface along a desired line of cut, such that said cutter is translated on a locus of points lying in a plane substantially parallel to said sheet material during said cutting operation, said means providing a supporting surface comprising a bed of material including a body portion made of material readily penetrable by said cutting tool, and a skinlike top layer of material superimposed on said portion and directly forming said supporting surface, said cutting tool during a cutting operation passing through said top layer and penetrating said body portion of said bed, said top layer being made of a material which is restorable through the action of a restoring medium to heal cuts therein after having been penetrated and cut by said cutting tool during a cutting operation.

2. The combination defined in claim 1 further characterized by said top layer of said bed including a thermoplastic material, and means for periodically heating said top layer to restore said supporting surface.

3. The combination defined in claim 2 further characterized by said body portion of said bed being made of a fibrous material.

4. The combination defined in claim 1 further characterized by said top layer of said bed including a solvent soluble material which is restorable by the application of a solvent material, and means for periodically applying a solvent to said top layer to restore said supporting surface.

5. In a sheet material cutting apparatus the combination comprising means providing a supporting surface for supporting in a spread condition sheet material to be cut, a cutter having a cutting tool, means for supporting and moving said cutter and said supporting surface relative to one another in such a manner that during a cutting operation said cutting tool passes through and cuts the material on said supporting surface and penetrates said supporting surface and so that said cutting tool is movable relative to said supporting surface along a desired line of cut, said means providing a supporting surface comprising a bed of material including a body portion made of a material readily penetrable by said cutting tool, and a top layer of material superimposed on said body portion and directly forming said supporting surface, said top layer of said, bed including a material which is restorable by the application of ultrasonic -wave energy thereto to heal cuts therein after having been penetrated and cut by said cutting tool during a cutting operation, and means for periodically applying ultrasonic wave energy to said layer to effect a restoration of said supporting surface.

6. A supporting surface defining a bed of material for use in a sheet material cutting apparatus of the type which utilizes a reciprocating blade or similar cutting tool which is translated substantially normal to the direction of reciprocation of said blade and which cuts the supporting surface and penetrates the bed by a given distance during a cutting operation, said bed comprising: a body portion made of a material readily penetrable by a cutting tool, and a relatively thin skinlike top surface layer portion overlying said body portion and directly defining said supporting surface and made of material capable of being restored to a continuous state through the application of a restoring medium after it has been cut during a cutting operation, said top surface layer portion having a thickness substantially less than said given distance by which said cutting tool penetrates said bed whereby said cutting tool in penetrating said bed passes completely through said top surface layer portion and penetrates said body portion while cutting along a locus of points lying in a plane substantially normal to the direction of reciprocation of said blade.

7. A bed as defined in claim 6 further characterized by said top surface layer portion being made of a thermoplastic material which may be restored by the application of heat thereto.

8. A bed as defined in claim 7 further characterized by said body portion thereof being made of felt, and said top surface layer portion including a thermoplastic material.

9. A bed as defined in claim 6 further characterized by said top surface layer portion comprising a solvent soluble material which is restorable by the application of a solvent thereto after a cutting operation.

10. A supporting surface defining bed of material for use in a sheet material cutting apparatus of the type which utilizes a reciprocating blade or similar cutting tool which penetrates and cuts the supporting surface during a cutting operation, said bed comprising: a relatively thick body portion made of a material readily penetrable by a cutting tool, and a relatively thin top surface layer portion directly defining said supporting surface and made of a material which is restorable to a continuous state by the application of ultrasonic wave energy thereto after it has been cut during a cutting operation.

11. A method for cutting sheet material by means of a reciprocating cutting tool which method comprises the steps of providing a bed having a body portion made from a material readily penetrable by a cutting tool and a skinlike surface layer portion overlying said body portion, translating said reciprocating cutting tool substantially normal to the direction of reciprocation of said cutting tool in the region adjacent to said cutting tool during each of said strokes, said skinlike surface layer portion defining a supporting surface and being made from a material which is restorable through the' action of a restoring medium to heal cuts therein after having been penetrated and cut by a cutting tool during a cutting operation, placing sheet material to be cut on said supporting surface, cutting said sheet material with a reciprocating cutting tool cutter which during each stroke passes through and cuts booth said sheet material and said skin-like surface layer portion and which penetrates and cuts said supporting surface said body portion, and thereafter restoring said skinlike surface layer portion supporting surface to heal the cuts made in said supporting surface therein by said cutting tool and to render it substantially continuous for use in a subsequent cutting operation.

12. The method defined in claim 11 further characterized by said step of providing a bed involving the provision of a bed having a skin-like surface layer portion made of a thermoplastic material, and said step of restoring said supporting surface being accomplished by heating said surface layer portion of said bed to soften the material thereof to the point where the material on opposite sides of cuts therein is united and then removing the heat to allow said material to resolidify to a continuous state.

13. The method defined in claim 11 further characterized by said step of providing a bed involving the provision of a bed having a skinlike surface layer portion made of a solvent soluble material, and said step of restoring said surface being accomplished by applying a solvent to said surface layer portion of said bed.

14. A method for cutting sheet material which method comprises the steps of providing a bed of material having a supporting surface, placing sheet material to be cut on said supporting surface, cutting said sheet material with a cutter which passes through said sheet material and penetrates and cuts said supporting surface, and thereafter restoring said supporting surface to heal the cuts made therein by said cutting tool and to render it substantially continuous for use in a subsequent cutting operation, said step of providing a bed involving the provision of a bed having a surface layer portion defining said supporting surface which surface layer portion is made of a material which changes state from substantially a solid to substantially a liquid in the presence of ultrasonic wave energy, and said step of restoring said surface being accomplished by exposing said surface layer portion of said bed to ultrasonic wave energy.

15. A method for cutting sheet material which method comprises the steps of providing a bed of material having a supporting surface, placing sheet material to be cut on said supporting surface, cutting said sheet material with a cutter which passes through said sheet material and penetrates and cuts said supporting surface, and thereafter restoring said supporting surface to heal the cuts made therein by said cutting tool and to render it substantially continuous for use in a subsequent cutting operation, said step of restoring said supporting surface being accomplished by spreading a sheet of thermoplastic material over said surface and thereafter heating said sheet to bond it to said supporting surface.

ing an adhesive to said supporting surface and thereafter applying a thin sheet of material over said supporting surface so as to be bonded thereto by said adhesive.

17. The method defined in claim 11 further characterized by said step of restoring said supporting surface being accomplished by spreading over said supporting surface a hardenable liquid, and thereafter hardening said hardenable liquid.

Claims

5. In a sheet material cutting apparatus the combination comprising means providing a supporting surface for supporting in a spread condition sheet material to be cut, a cutter having a cutting tool, means for supporting and moving said cutter and said supporting surface relative to one another in such a manner that during a cutting operation said cutting tool passes through and cuts the material on said supporting surface and penetrates said supporting surface and so that said cutting tool is movable relative to said supporting surface along a desired line of cut, said means providing a supporting surface comprising a bed of material including a body portion made of a material readily penetrable by said cutting tool, and a top layer of material superimposed on said body portion and directly forming said supporting surface, said top layer of said bed including a material which is restorable by the application of ultrasonic wave energy thereto to heal cuts therein after having been penetrated and cut by said cutting tool during a cutting operation, and means for periodically applying ultrasonic wave energy to said layer to effect a restoration of said supporting surface.

6. A supporting surface defining a bed of material for use in a sheet material cutting apparatus of the type which utilizes a reciprocating blade or similar cutting tool which is translated substantially normal to the direction of reciprocation of said blade and which cuts the supporting surface and penetrates the bed by a given distance during a cutting operation, said bed comprising: a body portion made of a material readily penetrable by a cutting tool, and a relatively thin skin-like top surface layer portion overlying said body portion and directly defining said supporting surface and made of material capable of being restored to a continuous state through the application of a restoring medium after it has been cut during a cutting operation, said top surface layer portion having a thickness substantially less than said given distance by which said cutting tool penetrates said bed whereby said cutting tool in penetrating said bed passes completely through said top surface layer portion and penetrates said body portion while cutting along a locus of points lying in a plane substantially normal to the direction of reciprocation of said blade.

11. A method for cutting sheet material by means of a reciprocating cutting tool which method comprises the steps of providing a bed having a body portion made from a material readily penetrable by a cutting tool and a skinlike surface layer portion overlying said body portion, translating said reciprocating cutting tool substantially normal to the direction of reciprocation of said cutting tool in the region adjacent to said cutting tool during each of said strokes, said skinlike surface layer portion defining a supporting surface and being made from a material which is restorable through the action of a restoring medium to heal cuts therein after having been penetrated and cut by a cutting tool during a cutting operation, placing sheet material to be cut on said supporting surface, cutting said sheet material with a reciprocating cutting tool cutter which during each stroke passes through and cuts booth said sheet material and said skin-like surface layer portion and which penetrates and cuts said supporting surface said body portion, and thereafter restoring said skinlike surface layer portion supporting surface to heal the cuts made in said supporting surface therein by said cutting tool and to render it substantially continuous for use in a subsequent cutting operation.

16. A method for cutting sheet material which method comprises the steps of providing a bed of material having a supporting surface, placing sheet material to be cut on said supporting surface, cutting said sheet material with a cutter which passes through said sheet material and penetrates and cuts said supporting surface, and thereafter restoring said supporting surface to heal the cuts made therein by said cutting tool and to render it substantially continuous for use in a subsequent cutting operation, said step of restoring said supporting surface being accomplished by applying an adhesive to said supporting surface and thereafter applying a thin sheet of material over said supportIng surface so as to be bonded thereto by said adhesive.