WO2000013863A1

WO2000013863A1 - Vacuum hold-down method and apparatus for cutting sheet material

Info

Publication number: WO2000013863A1
Application number: PCT/US1999/020528
Authority: WO
Inventors: Daniel C. House
Original assignee: Eastman Machine Company
Priority date: 1998-09-08
Filing date: 1999-09-08
Publication date: 2000-03-16
Also published as: WO2000013863A9

Abstract

A system for cutting sheets having a vacuum conveyor (12), a cutting unit gantry (14) and an air-impermeable cover sheet (20) looping around the cutting unit gantry (14).

Description

VACUUM HOLD-DOWN METHOD

AND APPARATUS FOR CUTTING

SHEET MATERIAL

Cross-Reference to Related Application

Applicant hereby claims priority based on Provisional Application No. 60/099,380 filed September 8, 1998, and entitled "Vacuum Hold-Down Method and Apparatus for Cutting Sheet Material," which is incorporated herein by reference.

Background of the Invention

This invention relates to the art of performing operations such as cutting on sheet material such as cloth, and more particularly to a new and improved system and method for holding sheet material during cutting thereof.

Static vacuum tables and conveyors using vacuum are employed to hold sheet material while cutting and similar operations are performed on the material. The table surface or conveyor belt is porous so that a vacuum created below serves to hold the sheet material on the top of the table surface or conveyor belt . Certain sheet materials due to their porosity and/or thickness are difficult to hold down by such vacuum arrangements during cutting and similar operations.

Summary of the Invention

It would therefore be highly desirable to provide a new and improved vacuum system and method for holding sheet material during cutting and similar operations thereon.

The present invention provides a system and method for holding materials on a conveyor using vacuum and an overlay sheet. The overlay sheet is a continuous belt moving with the conveyor and suspended over the top of the conveyor so that the bottom of the overlay sheet is in contact with the top of the conveyor belt . It is required that the conveyor belt be porous and that the overlay sheet be nonporous . The materials to be conveyed are placed on the conveyor ahead of the overlay sheet so that they are subsequently contained between the conveyor belt and the overlay sheet.

A gantry may be placed over the top of the conveyor to allow the materials being conveyed to be cut or marked or otherwise modified. This gantry may move up and down the conveyor between the overlay sheet and the conveyor. The gantry should have rollers or other means to support the overlay sheet above it . The overlay sheet, which is fed over the gantry, allows free access to the materials being conveyed by the conveyor for cutting or marking or other modification without any damage to the overlay sheet .

Further the same system and method may be used on a static vacuum table with the overlay sheet fastened to the ends of the table and passing over the gantry, allowing free movement of the gantry up and down the table.

Thus, the system and method of the present invention provides a moving vacuum that compresses and holds sheet material in place during cutting.

The following detailed description of the invention, when read in conjunction with the accompanying drawings wherein the same reference numerals denote the same or similar parts throughout the several views, is in such full, clear, concise and exact terms as to unable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the invention.

Brief Description of the Drawings

Fig. 1 is a perspective view illustrating the system and method of the present invention;

Fig. 2 is a side elevational view further illustrating the system and method of the present invention; and

Fig. 3 is a diagrammatic view illustrating a portion of the apparatus shown in Fig. 3.

Detailed Description of the Invention

The system and method of the present invention is shown in Fig. 1 with a continuous cutting system including a conveyor 10 having a moving belt 12 and a gantry 14 movable longitudinally along conveyor 10 and provided with a cutter mechanism (not shown) or similar tool which moves laterally across conveyor 10 for operating on the sheet material. The direction longitudinally along conveyor 10 can be designated the X axis direction and the direction laterally of conveyor 10 and be designated the Y axis direction. Conveyor belt 12 is of microporous material, and a vacuum created within conveyor 10 below belt 12 holds down the sheet material on the top of belt 12. The foregoing continuous cutting system is shown and described in pending United States patent application Serial No. 08/941,891 filed September 30, 1997 entitled "Continuous System and Method for Cutting Sheet Material", the disclosure of which is hereby incorporated by reference.

The system of the present invention comprises a continuous overlay sheet generally designated 20 which compresses and holds down porous and thick fabrics and like sheet material. The overlay sheet 20 is a continuous belt moving with the conveyor belt 12 and suspended over the top of the conveyor belt 12 so that the bottom of the overlay sheet 20 is in contact with the top of the conveyer belt 12. Sheet 20 can be of any thin, flexible non-porous plastic material and typically is transparent. The materials to be conveyed are placed on conveyor 10 at the input end designated 22 in Fig. 1 and ahead of the overlay sheet 20 so that they are subsequently contained between the conveyor belt 12 and overlay sheet 20.

The sections or parts 24 of material cut by the system shown in Fig. 1 are seen leaving conveyor 10 at the output end 26 thereof. Comparing the thickness of parts 24 to the thickness of the material between sheet 20 and belt 12 shown in Fig. 1, it is apparent that overlay sheet 20 compresses and holds down porous and thick fabrics and similar sheet material.

By way of example, the system and method of the present invention handles hard to hold down material such as foam, mesh, lawn chair webbing, denim, tubular knit fabrics, other 2 ply material, fiberglass, fiberfill, high loft fabrics, polyester fiber and other thick and porous sheet material .

Gantry 14 moves longitudinally back and forth along conveyor belt 12 and between sections of overlay sheet 2o. Gantry 14 has rollers 30, 32, 34 and 36 rotatably mounted on a frame carried by gantry 14 for supporting overlay sheet 20. The rollers 30, 32, 34 and 36 of course travel with gantry 14. Additional rollers 40, 42, 44 and 46 are rotatably mounted in arms 50, 52, 54 and 56 fixed to and near the opposite ends of conveyor 10 and provide additional support for overlay sheet 20. Preferably all the rollers are ball bearing type rollers. At least one of the rollers, for example roller 42 or 46, is connected to and driven by the drive system for the conveyor 10, a drive coupling mechanism for accomplishing this being partially shown at 60 in Fig. 1.

Fig. 2 illustrates a vacuum hold-down system and method used in a continuous cutting system comprising conveyor 10' and a pair of gantries 14', 14". Gantries 14', 14" move longitudinally along conveyor 10' and each is provided with a cutter mechanism (not shown) or similar tool which moves laterally across conveyor 10' for operating on the sheet material. The two gantry continuous cutting system of Fig. 2 is shown and described in further detail in the above-identified patent application Ser. No. 08/941,891. Rollers 30', 32', 34' and 36' are rotatably mounted in arms or frame members, two of which are shown at 70 and 72 in Fig. 2, which are carried by gantry 14'. Similarly, rollers 80, 82, 84 and 86 are rotatably mounted in arms or frame members, two of which are shown at 90 and 92 in Fig. 2, which are carried by gantry 14". The sets of rollers 30', 32', 34' and 36' and 80, 82, 84 and 86 move along conveyor 10' with their corresponding gantries 14' and 14", respectively. Also shown in Fig. 2 are the additional rollers 40', 42', 44' and 46' which are rotatably mounted in arms or frames, two of which are shown at 50' and 54' in Fig. 2, fixed to and located near the opposite ends of conveyor 10'. Preferably, all the rollers are ball bearing type rollers. At least one of the rollers, for example roller 42 or 46, is connected to and driven by the drive system for the conveyor 10', a drive coupling mechanism for accomplishing this being like that designated 60 in Fig. 1. This drive roller for the overlay sheet is preferably driven at the same speed as the conveyor belt 12 ' . The remaining rollers are preferably idler rollers that guide the overlay sheet around a specific path.

The overlay sheet or rolling curtain 20', like overlay or curtain 20 in Fig. 1 is continuous and has an outer or upper section 100 as viewed in Fig. 2 which is spaced from conveyor belt 12 ' , an inner section 102 adjacent conveyor belt 12' which contacts the surface of the sheet material on conveyor belt 12 ' and an intermediate section associated with the gantry and trained around the rollers associated with the gantry. In the illustrative arrangement of Fig. 2 there are two intermediate sections 104 and 106 associated with gantries 14' and 14", respectively.

The relationship between one of the overlay intermediate sections and one of the gantries, for example section 104 and gantry 14 ' is shown in further detail in Fig. 3. A tool such as a cutter knife 110 is moved toward and away from the sheet material to be cut by an air driver tool head 112 or similar mechanism. Tool 110 and head 112 are carried by gantry 14 ' (not shown in Fig. 3) and are moved along the gantry 14', i.e. laterally of conveyor belt 12', by a suitable motive means in gantry 14 ' . The intermediate section 104 of overlay 20' is trained around the rollers 30', 32', 34' and 36' carried by gantry 14' as previously described and also around a pair of additional rollers 120 and 122 carried by gantry 14' . The intermediate section 104 meets the inner section 102 of overlay 20' at the additional rollers 120, 122 which define a space or opening therebetween to allow tool 110 to be lowered for cutting the sheet material without cutting the overlay 20' . This space or region moves longitudinally along conveyor belt 12 ' with gantry 14 ' thereby enabling gantry 14' and its tool 110 to operate on the entire region of sheet material on conveyor belt 12 ' without cutting the overlay 20'. An identical arrangement is provided on gantry 14 " .

Thus, the tough transparent overlay 20' (and overlay 20 shown in Fig. 1) rolls in a continuous loop and is never cut, eliminating expensive consumable plastic and the labor involved to separate the plastic from the fabric or other sheet material being cu . The continuous overlay compresses and keeps the sheet material in place during cutting, and advantageously operates well with continuous, "on the fly" cutting systems as described herein.

It is therefore apparent that the present invention accomplishes its intended objectives. While embodiments of the present invention have been described in detail, that has been done for the purpose of illustration, not limitation.

Claims

The Claims What is claimed is:

1. An apparatus for cutting sheet material, comprising: a work table having an air-permeable surface disposed thereon, the work table having a vacuum unit operative on the work surface such that the air- permeable surface is in fluid communication with the vacuum unit; an overlay sheet of substantially air impermeable material capable of being removably attached at opposite ends of the work table; a cutting unit movable relative to the work table to cut the sheet material, the sheet material being disposed between the overlay sheet and the air permeable surface; and, a plurality of bearing surfaces disposed on the cutting unit and capable of supporting the overlay sheet such that the overlay sheet is disposed adjacent to the work table on opposite sides of the cutting unit and is supported above the cutting unit such that the cutting unit is capable of slidably moving relative to the overlay sheet so that the overlay sheet is not cut by the cutting unit while cutting the sheet material.

2. The apparatus of Claim 1, wherein the bearing surfaces comprise idler rollers.

3. The apparatus of Claim 1, wherein the overlay sheet extends substantially parallel to the work table from a first end until it reaches a plurality of rollers supported by and moveable with the cutting unit, the rollers being disposed such that the sheet passes upward and over the cutting unit, a first roller on a first side of the cutting unit is disposed adjacent to the work table and turns the overlay sheet upward toward rollers that guide the air-impermeable sheet over the top of the cutting unit, the cutting unit having a second roller disposed adjacent to the work table on the opposite side of the cutting unit such that the air- impermeable sheet is turned from the downward direction into a direction substantially parallel to the work table.

4. An apparatus for cutting sheet material, comprising: a conveyor having an air-permeable conveyor belt capable of conveying the sheet material, the conveyor having a vacuum unit operative with the belt such that the conveyor belt is in fluid communication with the vacuum unit ; an endless overlay sheet of substantially air impermeable material disposed such that least a portion of the overlay sheet is disposed adjacent to the conveyor belt; a cutting unit movable relative to the conveyor to cut the sheet material, the sheet material disposed between the conveyor belt and the overlay sheet; at least one drive capable of conveying the overlay sheet; a plurality of bearing surfaces capable of guiding the overlay sheet in a loop; and, the at least one drive and the plurality of bearing surfaces disposed such that the overlay sheet is disposed adjacent to the conveyor belt on opposite sides of the cutting unit and is supported above and moves relative to the cutting unit such that the overlay sheet is not cut by the cutting unit while cutting the sheet of material .

5. The apparatus of Claim 4, wherein the drive comprises a drive roller connected to a drive system for the conveyor .

6. The apparatus of Claim 4, wherein the bearing surfaces comprise idler rollers.

7. The apparatus of Claim 4 , wherein the overlay sheet of material is conveyed at substantially the same speed as the conveyor belt .

8. The apparatus of Claim 4, wherein the conveyor has at least one arm for supporting at least one of the bearing surfaces for the overlay sheet .

9. The apparatus of Claim 4, wherein the cutting unit supports at least one of the bearing surfaces .

10. The apparatus of Claim 4, wherein the cutting unit comprises two cutting units.

11. The apparatus of Claim 4, wherein the cutting unit is capable of moving in an X-axis aligned with the conveyor belt and a Y-axis normal to the conveyor belt.

12. The apparatus of Claim 11, wherein the loop traveled by the overlay sheet is defined in part by a pair of rollers at opposite ends of the conveyor, at the first end a first roller is disposed adjacent to the surface of the conveyor belt and a second roller is disposed above the surface of the conveyor belt in spaced apart relation to the first roller, at the second end a third roller is disposed adjacent to the surface of the conveyor belt and a fourth roller is disposed above the surface of the conveyor belt in spaced apart relation to the third roller, the overlay sheet traveling along the X-axis in the same direction as the conveyor belt until it reaches the first roller where it turns upward toward the second roller, the overlay sheet being directed by the second roller along the X-axis in a direction opposite to the direction of the conveyor belt in order to complete a substantially one-hundred eighty degree turn, the overlay sheet entering the fourth roller at the opposite end of the conveyor and turning downward toward the third roller, the overlay sheet exiting the third roller along the X-axis in the direction of the conveyor belt to complete a substantially one-hundred eighty degree turn and being disposed adjacent to the conveyor belt.

13. The apparatus of Claim 12 , wherein the overlay sheet exits the third roller and travels along the X- axis in the direction of the conveyor belt until it reaches a plurality of rollers supported by and moveable with the cutting unit, the rollers being disposed such that the overlay sheet passes upward and over the cutting unit, a fifth roller disposed adjacent to the conveyor belt and turning the overlay sheet upward to rollers that guide the overlay sheet over the top of the cutting unit, the cutting unit having a sixth roller disposed adjacent to the conveyor belt on the opposite side of the cutting unit from the fifth roller such that the overlay sheet is turned from the downward direction into the X-axis direction in the same direction as the conveyor belt and adjacent to the conveyor belt, the overlay sheet traveling substantially parallel to the conveyor from the sixth roller to the first roller.

14. An apparatus for cutting sheet material, comprising: a conveyor having an air-permeable conveyor belt capable of conveying the sheet material, the conveyor having a vacuum unit operative with the belt such that the air-permeable belt is in fluid communication with the vacuum unit; an endless overlay sheet of substantially air impermeable material disposed such that least a portion of the overlay sheet is disposed adjacent to the conveyor belt; a cutting unit movable relative to the conveyor to cut the sheet material, the sheet material disposed between the conveyor and the overlay sheet; at least one driven roller capable of driving the overlay sheet at substantially the same speed as the conveyor belt; a plurality of idler rollers capable of guiding the overlay sheet in a loop; and, the driven roller attached to a frame supported by the conveyor; a plurality of the idler rollers supported by the cutting unit such that the overlay sheet is directed over the cutting unit such that the cutting unit does not cut the overlay sheet while cutting the sheet of material.

15. The apparatus of Claim 14 , wherein the overlay sheet of material is conveyed at substantially the same speed as the conveyor belt .

16. The apparatus of Claim 14, wherein the conveyor has at least one arm for supporting at least one of the idler rollers for the overlay sheet.

17. The apparatus of Claim 14, wherein the cutting unit supports at least one of the idler rollers.

18. The apparatus of Claim 14, wherein the cutting unit is capable of moving along an X-axis in alignment with the conveyor belt and a Y-axis normal to the conveyor belt.

19. The apparatus of Claim 14, wherein the loop traveled by the overlay sheet is defined in part by a pair of rollers at opposite ends of the conveyor, at the first end a first roller is disposed near the surface of the conveyor belt and a second roller is disposed above the surface of the conveyor belt in spaced apart relation to the first roller, at the second end a third roller is disposed near the surface of the conveyor belt and a fourth roller is disposed above the surface of the conveyor belt in spaced apart relation to the third roller, the overlay sheet traveling along the X-axis in the direction of the conveyor belt until it reaches the first roller where it turns upward toward the second roller, the overlay sheet being directed by the second roller along the X-axis in a direction opposite to the direction of the conveyor belt in order to complete a substantially one-hundred eighty degree turn, the overlay sheet entering the fourth roller at the opposite end of the conveyor and turning downward toward the third roller, the overlay sheet exiting the third roller in the X-axis direction in the same direction as the conveyor belt to complete a substantially one-hundred eighty degree turn and being disposed adjacent to the conveyor belt .

20. The apparatus of Claim 19, wherein the overlay sheet exits the third roller and travels along the X- axis until it reaches a plurality of rollers supported by and moveable with the cutting unit, the rollers disposed such that the overlay sheet passes upward and over the cutting unit, a fifth roller on a first side of the cutting unit is disposed adjacent to the conveyor belt and turns the overlay sheet upward to rollers that guide the overlay sheet over the top of the cutting unit, the cutting unit having a sixth roller disposed on the side of the cutting unit opposite the fifth roller and disposed adjacent to the conveyor belt such that the overlay sheet is turned from the downward direction into the X-axis direction in the same direction as the conveyor belt .

21. A method of cutting a sheet of material, comprising the steps of: providing a work table having an air-permeable surface disposed thereon, the work table having a vacuum unit operative on the work surface such that the work surface is in fluid communication with the vacuum unit; a cutting unit movable relative to the work table to cut a stack of sheet material; an overlay sheet of substantially air impermeable material capable of being removably attached at opposite ends of the work table; a plurality of idler rollers disposed on the cutting unit and capable of supporting the overlay sheet such that the overlay sheet is disposed adjacent to the work table on opposite sides of the cutting unit and is supported above the cutting unit such that the cutting unit is capable of moving relative to the overlay sheet so that the overlay sheet is not cut by the cutting unit while cutting the sheet of material; placing the sheet of material onto the work table; placing the overlay sheet over the sheet of material ; attaching the overlay sheet at one end of the work table to form an attached end and a free end; threading the free end through the rollers on the cutting unit; attaching the free end of the overlay sheet to the opposite end of the work table; cutting the stack of sheet material while the vacuum unit is operative on the work table.

22. A method of cutting a sheet of material, comprising the steps of : providing a conveyor having an air-permeable conveyor belt capable of conveying the sheet material, the conveyor having a vacuum unit operative with the belt such that the conveyor belt is in fluid communication with the vacuum unit; an endless overlay sheet of substantially air impermeable material disposed such that least a portion of the overlay sheet is disposed adjacent to the conveyor belt; a cutting unit movable relative to the conveyor to cut the sheet material; at least one drive capable of conveying the overlay sheet; a plurality of bearing surfaces capable of guiding the overlay sheet in a loop; and, the at least one drive and the plurality of bearing surfaces disposed such that the overlay sheet is disposed adjacent to the conveyor belt on opposite sides of the cutting unit and is supported above and moves relative to the cutting unit such that the overlay sheet is not cut by the cutting unit while cutting the sheet of material ; placing the sheet of material onto the conveyor such that the sheet is disposed between the conveyor belt and the overlay sheet; conveying the sheet of material while simultaneously cutting the material with the cutting unit without cutting the overlay sheet.