GB2068133A

GB2068133A - An apparatus for determining a line of cut along a sheet of material

Info

Publication number: GB2068133A
Application number: GB8002662A
Authority: GB
Original assignee: Lucas & Son Ltd W G
Current assignee: Lucas & Son Ltd W G
Priority date: 1980-01-25
Filing date: 1980-01-25
Publication date: 1981-08-05
Also published as: GB2068133B

Abstract

An apparatus for marking cutting lines on sheet sail cloth 11 comprises a flat elongate table 10 along which a carriage 14 extending across the table is linearly movable by a drive motor 15, guide rail 12, pulleys 16, 17 and cable 18. The carriage has a toothed rack 18 mounted for sliding movement along the carriage under the control of a stepper motor 19 on the carriage and pinion 20. A pen carrier 24 slides on the carriage by means of a drive motor (not shown) and pinion 25 connected to the rack to move the pen carrier transversely of the table in accordance with a predetermined programme to define the required line of cut on the sail cloth 11. The marking is controlled relative to one edge of the cloth by a sensing head 21 having infra-red sources/detectors 22,23 mounted on the carriage to detect the edge and, through the stepper motor 19, to adjust the position of the rack to compensate for variation in the position of said edge of the cloth along the table. In another embodiment (Fig. 3, not shown), the carriage 14 is mounted stationary above a driven drum and the cloth passes between the drum and carriage. <IMAGE>

Description

SPECIFICATION An apparatus for determining a line of cut along a sheet of material This invention relates to an apparatus for determining a line of cut along a sheet of material in relation to an edge of the material and is particularly although not exclusively applicable to apparatus for marking sail cloth in accordance with the required panel shape to be cut from the cloth.

The invention provides an apparatus for determining a line of cut along a sheet of material in relation to an edge of the material comprising, a surface to support a sheet of material from which a strip is to be cut, means to define a line of cut on a sheet of material on the surface means to move the surface and cut defining means relative to one another and contactless sensing means to detect an edge of the sheet material and to adjust the line of cut defining means to a required position in relation to the edge of the material The following is a specific description of a specific embodiment of the invention, reference being made to the accompanying drawings in which:: Figure 1 is a diagrammatic plan view of a sail cloth plotting machine; Figure 2 is a view looking in the direction of the arrow 2 on Fig. 1, and Figures 3 and 4 show an alternative construction.

Referring firstly to Fig. 1 of the drawings, there is shown a plotting machine for marking sail cloth with the required shapes of the panels from which sails are to be made up comprising a flat elongate table 10 on which lengths of said cloth 11 are laid for marking.

Parallel guide rails 12, 13, mounted on the table surface adjacent the side edges thereof extend substantially the full length of the table and a carriage 14 is mounted on the guide rails to move forwards and backwards along the table. A main drive motor 1 5 is mounted at one end of the table adjacent one end of the guide rail 1 2. The motor has an output drive pulley 1 6. A freely rotatable pulley 1 7 is mounted at the other end of the table adjacent the other end of the guide rail 1 2 and an endless cable 1 8 extends between the pulleys 16, 1 7. The carriage 14 is attached to the upper stretch of the cable 1 8 so that rotation of the drive motor 1 5 moves the carriage 1 4 linearly along the table surface.

Referring now to Fig. 2 of the drawings, the carriage 1 4 has a toothed rack 1 8 mounted for linear sliding movement on the carriage transverse to the direction of movement of the carriage along the table. A stepping motor 1 9 (see Fig. 1) is mounted on the carriage and has an output drive pinion 20 which meshes with the rack adjacent one end of the rack. A sensing head 21 is mounted on the rack and the underside of the head has two closely set pairs of infra-red sources/detectors 22, 23 set slightly apart in a direction transverse to the direction of movement of the traveller along the table. The table has a greater reflectance than the sail cloth so that the detectors can determine whether they are positioned over the sail cloth or over the table.The resulting pulses received from the detectors are fed to logic circuits (not shown) which de-code the information and control the operation of the stepper motor 1 9 to maintain the sensing head and thereby the rack 1 8 in a position in which the detectors bridge the edge of the sail cloth with detector 23 located over the sail cloth and the detector 22 located over the table. Thus the sensing head adjusts the position of the rack in relation to the edge of the sail cloth 11 as the carriage 1 4 moves along the table. At the other end of the carriage 1 4 a pen carrier 24 is mounted for sliding movement along the carriage transverse to the direction of travel of the carriage along the table.The pen carrier has a further stepping motor (not shown) mounted therewith having an output pinion 25 which meshes with the rack 1 8. The pen carrier carries a pen mounted on centre line 26 on the trailing side of the carrier for marking the sailcloth along the required line of cut immediately after the edge of the cloth has been sensed by the sensing head 21 and the pen carrier adjusted accordingly. When the pen carrier motor is stationary, the pen carrier moves with the rack 1 8 following the edge of the sailcloth as determined by the detectors 22, 23. The motor of the pen carrier is operated by, for example, a micro-computer in accordance with a predetermined programme to move the carrier with respect to the rack to define a required line of cut along the sailcloth in accordance with the shape of the panel required.

The arrangement thus enables the edge of the cloth to be detected and followed so that all measurements across the cloth are taken relative to that edge. Thus that edge requires no margin to be wasted and any margin on the other edge can be relatively narrow.

The marker pen may be replaced by a cloth cutter such as a hot wire cutter if direct cutting of the cloth without prior marking is required.

Referring now to Figs. 3 and 4 of the drawings, there is shown a further plotting machine in which the cable 10 is replaced by a drum 30 which is driven through a belt 31 by an eiectric drive motor 32. Sail cloth is fed to the drum from a reel 33 and passes over an upper part of the drum and thence to a take-up roll 34. The moving carriage of the previously described embodiment is replaced by a fixed carriage 1 4 mounted above the surface of the drum 30 and extending parallel to the drum axis and the sensing head 21 and pen carrier 24 are mounted on the carriage as described previously. The infra-red sources/detectors 22, 23 of the sensing head 21 face the drum surface and so as cloth is fed by the drum surface past the sensing head, the sensing head moves to detect the edge of the cloth and adjust the cut defining means 24 accordingly.

Claims

1. An apparatus for determining a line of cut along a sheet of material in relation to an edge of the material comprising, a surface to support a sheet of material from which a strip is to be cut, means to define a line of cut on a sheet of material on the surface means to move the surface and cut defining means relative to one another and contactless sensing means to detect an edge of the sheet of material and to adjust the line of cut defining means to a required position in relation to the edge of the material.

2. An apparatus as claimed in claim 1 wherein the surface is a flat surface and a traveller is provided which carries the cut defining means and which is moveable linearly over the surface.

3. An apparatus as claimed in claim 2 wherein means are provided on the traveller for moving the line of cut defining means on the traveller transversely to the direction of movement of the traveller over the surface under the control of the sensing means-to locate the line of cut in the requisite position in relation to the edge of the sheet.

4. An apparatus as claimed in claim 3 wherein the line of cut defining means is moveably mounted on the traveller transverse to the direction of movement of the latter, means are provided for moving the line of cut defining means with respect to the traveller as the traveller moves along the surface to define the required shape of the line of cut on the sheet of material and the sensing means is arranged to move the line of cut defining means in relation to the edge of the material.

5. An apparatus as claimed in claim 4 wherein the sensing means is mounted on a support movably mounted on the traveller for movement transverse to the direction of movement of the traveller over the surface and a drive motor controlled by the sensing means is mounted on the traveller and is connected through a drive mechanism to the support to adjust the support along the traveller in accordance with the location of the edge of the material detected by the sensing means to adjust as necessary the position of the line of cut defining means.

6. An apparatus as claimed in claim 5 wherein the support comprising a toothed rack mounted on the traveller for linear sliding movement transversely to the direction of movement of the traveller over the surface, the motor having an output pinion engaging the rack to displace the rack with respect to the traveller, the cut-defining means being mounted on the traveller for movement transverse to the direction of movement of the traveller and having a drive motor having an output pinion engaging the rack so that movement of the rack in response to the sensing means moves the cut-defining means and operation of the motor of the cut-defining means moves the cut-defining means in relation to the rack and therefore the edge of the strip of cloth to vary the shape of the strip as required.

7. An apparatus as claimed in any of the preceding claims wherein the sensing means comprises a pair of sensing devices spaced transverse to the direction of movement of the traveller, the two devices being arranged to detect whenever both devices are above either of the sheet of material or the surface to operate the motor in a direction to move the devices into a position where one is located over the sheet of material and the other is located over the table.

8. An apparatus as claimed in claim 7 wherein the sensing devices comprise two infra-red emitter devices and two corresponding infra-red detector devices.

9. An apparatus as claimed in any of the preceding claims wherein the traveller is supported on linearly extending guide rails and a drive motor is provided for moving the traveller along the rails.

1 0. An apparatus as claimed in claim 9 wherein an endless cable extends for the length of the rails and is connected to the traveller at one location and the drive motor is arranged to drive the cable in one or other direction to move the traveller in one or other direction along the rails.

11. An apparatus as claimed in claim 1 wherein the surface comprises a rotatable drum, the cut defining means and sensing means being mounted adjacent the surface of the drum so that rotation of the drum draws the material past the sensing means and cut defining means.

1 2. An apparatus as claimed in claim 11 wherein drive means are provided for rotating the drum to draw the material past the sensing means and cut defining means.

1 3. An apparatus as claimed in claim 11 or claim 1 2 wherein a support for the cut defining means extends lengthwise of the drum and a drive motor controlled by the sensing means is provided for adjusting the position of the cut defining means along the support.

14. An apparatus as claimed in any of claims 11 to 1 3 wherein the sensing means comprises a pair of sensing devices spaced apart in a direction parallel to the access of the drum, the two devices being directed towards the surface of the drum to detect whenever those devices are above either the sheet of material or the surface of the drum and with them the cut defining means into a position where one is located opposite the sheet of material and the other is located opposite the surface of the drum.

15. An apparatus as claimed in claim 14 wherein the sensing devices comprises two infra-red emitter devices and two corresponding infra-red detector devices.

1 6. An apparatus as claimed in any of the preceding claims wherein the line of cutdefining means comprises a pen for marking the sheet of material to be cut and or means to cut the sheet.

1 7. An apparatus for determining the line of cut along a strip of material in relation to an edge of the material substantially as described with reference to and as illustrated in Figs. 1 and 2 or Figs. 3 and 4 of the accompanying drawings.