AU2011239275A1 - Sheet Material Cutting Machine - Google Patents

Abstract

A cutting machine of the plotter type cuts sheets of flexible material such as fabric using a table covered in steel or glass. The table has a fabric feed at one end and a transverse clamp at the opposite end. A longitudinal clamp runs down one side of the table and twin longitudinal tracks are spanned by a transverse mobile clamp. A gantry above the table is free to traverse in the x axis and a cutter traverses in the y axis. The clamps hold the fabric on at least three sides when the intersecting cuts are made. 20]1-10-21,HASpecifications\Uhrct.cep2.wpd,6 2--5 ------- -- ----

Description

1 TITLE OF INVENTION Sheet Material Cutting Machine TECHNICAL FIELD [00011 This invention concerns a machine for cutting specific shapes from flat sheet material such as fabric, carpet and the like. BACKGROUND [0002] Manufacturers of blinds and awnings rely on cutting plotters for the precision cutting of fabric for these products. The fabric is fed from a roll across the worktable and data instruction enables the cutter to excise whatever shape is required. The cutter is able to move in the x and y axes and the fabric is immobilised during the cutting operation by the use of a perforated plastic worktable and the application of continuous vacuum. [0003] The necessity to use a steel or glass work top in turn limits the type of cutter in that ultrasonic cutters suit such surfaces, whereas wheel blades work best with a less durable work surface, typically polymeric material. [0004] A further problem in the design of cutting plotters is the presence of wrinkles and ripples in the fabric which spoil precision. Each time a fresh length of fabric is pulled from the bolt or roll adjacent the worktable there is the risk of undulation in the fabric. It is not practical to rely on a fabric feed which draws the fresh fabric across the worktable and then to impose tension in the feed direction in expectation that the fabric will be wrinkle free. As the operator changes to a different fabric the effect of imposing identical tension will produce a different lay in the fabric. SUMMARY OF INVENTION 201 l-IO-21,H:\$pecifications\ultracut.cap2.wpd,I 2 [0005] The apparatus aspect of the invention provides a cutting machine of the plotter type for cutting sheets of flexible material comprising a worktable with a pair of sides and a pair of ends, a sheet feed at one end, a stationary sheet clamp at the opposite end, tracks along the two sides spanned by a mobile clamp which is drivable toward and away from the stationary clamp by linear drive means, a sheet clamp along one side disposed at 900 to the stationary sheet clamp for clamping the side edge of a sheet, a gantry mounted above the table which traverses in the x axis and a cutter on the gantry with traverses in the y axis for the purpose of excising pieces from the sheet, a linear gantry clamp on the gantry beside the cutter operable to extend to the sheet material on the table and to overlie the mobile clamp at 900 and control means for indexing the gantry, the cutter and mobile clamp. Advantageous Effects of Invention [0006] 1. Choice of cutter. [0007] 2. Clamps are always applied on a minimum of three sides. BRIEF DESCRIPTION OF DRAWINGS [0008] One embodiment of the invention is now described with reference to the accompanying drawings, in which: [00091 Figure 1 is a plan. [0010] Figure 2 is an end view. [0011] Figure 3 is a perspective view. [0012] Figure 4 is a plan showing the cutting sequence. 2011-10-2 1,H:Specifications\uhracut.cap2.wpd,2 3 DESCRIPTION OF EMBODIMENTS [0013] Referring now to the drawings, worktable 2 (3300 x 4100mm) is waist high and is supported on legs 4. The cutting surface of the table is a steel or glass slab. Feed roll 10 allows fabric to be pulled across the table and laid beneath stationary clamp 12 at the opposite end. Clamp 12 is rotated between clamp and release positions by actuator 14. Side clamp 16 secures the side edge of sheet 18 via an actuator 19. [0014] Linear drive rails 20, 22 are spaced from the sides of the table and these support a transverse mobile clamp 24 lying at 900 to the side clamp 16. [0015] A pair of gantry bars 25 at the ends of the table span the table at a height of about 300mm and support a gantry beam 26 parallel to the fabric feed direction. The beam moves in the x axis and the cutter 28 travels along the beam in the y axis. The cutter 28 is either ultrasonic in operation or the blade type which crushes the fabric in order to prevent fraying of the excised edge. [0016] In addition gantry beam 26 supports beneath it an elongated, resilient plate clamp which has multiple side by side fingers 30 at 200mm centres moved between clamp and release positions by actuators 32. The edges of the fingers lie close to the cutter itself and press evenly on the fabric which may be 0.4-2mm thick without wrinkling it. The actuators are programmed to clamp and release. [0017] Linear drivers 34, 36 move the mobile clamp in the feed direction. Circuit box and console 38 allow the machine to be programmed. The purpose of the clamps 12, 16, 24 and fingers 30 to immobilise the fabric while the wheel blade cuts it. The adjustability of the gantry cutter means that any rectangle within the dimensions of the bolt can be cut by the plotter. [0018] Fabric is directed by hand beneath stationary clamp 12, beneath fingers 30, side clamp 16 and mobile clamp 24. Sample dimensions are keyed into the machine in order to determine the length of the four mutually intersecting cuts to be made by the cutter 28. In Figure 4, the 2011-10-2 1,H:\Specifications\ulhracut.cap2.wpd,3 4 fabric feed direction is indicated by arrow F. Once the fabric is checked for wrinkles the sequence is as follows. [00191 The mobile clamp moves to the third edge of the target rectangle. Cut one follows. Fingers 30 descend to clamp the fabric further. Cut 2 follows. Fingers 30 release. Cut 3 follows. Fingers 30 re-clamp. Cut 4 is the last cut. This sequence is repeated for subsequent pieces of fabric. [0020] It is to be understood that the word "comprising" as used throughout the specification is to be interpreted in its inclusive form, ic. use of the word "comprising" does not exclude the addition of other elements. [0021] It is to be understood that various modifications of and/or additions to the invention can be made without departing from the basic nature of the invention. These modifications and/or additions are therefore considered to fall within the scope of the invention. 201 t-I0-21,H:\Specificationsulxacijt cap2.wpd,4

Claims (7)

1. A cutting machine of the plotter type for cutting sheets of flexible material comprising a worktable with a pair of sides and a pair of ends, a sheet feed at one end, a stationary sheet clamp at the opposite end, a mobile clamp movable toward and away from the stationary clamp by linear drive means running on rails at the sides, a clamp along one side lying at 900 to the stationary and mobile clamps, a gantry mounted above the table which traverses in the x axis and a carriage on the gantry with associated cutter which together traverse in the y axis for the purpose of excising pieces from the sheet, a linear clamp supported on the gantry beside the cutter operable to extend to the sheet material on the table and to overlie the mobile clamp at 900 and control means for indexing the gantry, the cutter and mobile clamp.

2. A cutting machine as claimed in Claim 1, wherein the stationary clamp, side clamp and mobile clamp are each moved between clamp and release positions by an actuator.

3. A cutting machine as claimed in Claim 1 or 2, wherein the clamps each have multiple side by side fingers.

4. A cutting machine as claimed in any one of Claims 1-3, wherein the gantry linear clamp which traverses in the x axis and is segmented allowing any part of the clamp to accommodate the thickness of the mobile clamp beneath while still exerting clamping pressure on the sheet.

5. A cutting machine as claimed in Claim 4, wherein each segment is operated by an actuator.

6. A cutting machine as claimed in any one of Claims 1-5, wherein the cutter is a crush cutter or ultrasonic cutter.

7. A cutting machine substantially as herein described with reference to and as illustrated in the accompanying drawings.

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