APPARATUS FOR CONVEYING A FLEXIBLE SHEET OF MATERIAL

Abstract: Apparatus for conveying a flexible sheet of material (8), such as a web of container labels, has two cylindrical drums, a first drum (23) including a respective drive means, and the second (30) drum being movable by a drive coupling (32, 34) connected to the drive means, wherein the surface speed of the second drum (30) does not equal the surface speed of the first drum (23) and the flexible sheet of material (8) is transferred from the slower moving drum (30) to the faster moving drum (23).

Description: "Apparatus for Conveying a Flexible Sheet of Material" The invention relates to apparatus for conveying a flexible sheet of material and in particular, labels for attachment to a container. Conventionally, labelling machines use a series of rotating drums for the transport of labels through a series of stages. The labels are transferred from the surface of one drum to the surface of the next drum, and the labels are generally held on the surface of the drums by a vacuum. The drums are rotated so that the surface velocities of the drums are the same. However, due to variances in the surface speeds the labels may be wrinkled or creased as they are transferred from one drum to the next if the surface velocity of the receiving drum drops below the surface velocity of the drum from which the label is being transferred. This is obviously undesirable as it may result in creased labels on the final product. In accordance with the present invention, apparatus for conveying a flexible sheet of material comprises first and second movable surfaces adjacent to each other and adapted to transfer the sheet of material from one surface to the other surface, drive means to move the first movable surface and a drive coupling between the first movable surface and the second movable surface to move the second movable surface when the drive means moves the first movable surface in use, and wherein, the speed of the second movable surface is not equal to the speed of the irst movable surface and the flexible sheet of material is transferred from the slower moving surface to the faster moving surface. Typically, the movable surfaces may be continuous and are preferably cylindrical surfaces. Preferably, the movable surfaces are the curved surfaces of two drums which are typically cylindrical. Preferably the movable surfaces are a receiver surface and a feeder surface. Preferably the drive coupling comprises two co-operating gears, one gear coupled to each movable surface. Typically where the movable surfaces are cylindrical surfaces, the radius of the gear attached to the slower moving surface is greater than the radius of the slower moving surface and the radius of the gear attached to the faster moving surface is less than the radius of faster moving surface. Typically, the difference in speeds between the movable surfaces is less than 10%. Preferably the faster moving surface is the surface of a vacuum drum and the slower moving surface is the surface of a cutter drum and the flexible sheet of material may be a label to be applied to a container. An example of apparatus for conveying a flexible sheet of material in accordance with the invention will now be described with reference to the accompanying drawings in which:- Fig 1 is a schematic plan view of a labelling unit of a labelling machine; Fig 2 is a partial cross-sectional side view of the unit shown in Fig 1; and, Fig 3 is a plan view of a vacuum drum unit and cutter drum unit for the labelling unit shown in Figs 1 and 2. Figs 1 and 2 show a labelling unit for a labelling machine which takes a strip of labels 8 and applies one label 8 to a container 10 on a rotating lower turret 11 of a rotating lower turntable 12. An upper rotating turntable 13 having a number of rotating upper turrets 14 maintains the container 10 in position. Coupled to each lower turret 11 is a drive pulley 7 which engages with a drive belt 15 which moves in the direction of the arrow 16 in Fig 1 to rotate the lower turrets 11 in an anticlockwise direction, as shown by the arrow 17 in Fig 1. The turntable 12 is rotated in a clockwise direction 19 by a drive mechanism (not shown) coupled to a central axle 18 of the turntable 12. The labelling unit comprises a tensioner 20 to tension the labels as they enter the unit. A registration sensor 21 senses registration marks in each label to ensure that a cutter unit 2 cuts each label 8 from the strip incoming labels at the correct position, and a feed roller 22 feeds the strip of incoming labels to the cutter unit 2. A vacuum drum 23 receives the cut label 8 from the cutter unit 2, transports the label past a glue drum 24 which applies glue to the cut label 8 and as the vacuum drum 23 continues to rotate the glued label 8 is brought into contact with one of the containers 10 and as the container 10 rotates past the vacuum drum 23, the glued label 8 is applied to the surface of the container 10. The cutter unit 2 comprises a cutter drum 30 mounted on an axle 31 which has a gear 32 attached to the end remote from the drum 30. A rotating cutter blade 33 is mounted adjacent the drum 30 to cut each label 8 from the strip of labels. The vacuum drum 23 is mounted on an axle 34, the remote end of which is connected a drive mechanism (not shown) which rotates the axle 34. A gear 35 is rotationally fixed to the axle 34 so that engages and co-operates with the gear 32 on the axle 31 of the cutter drum 30. The vacuum drum 23 has three raised sections 36 on its surface which have openings (not shown) therein which enable labels to be held on the raised sections 36 by means of a suction or vacuum applied to the interior of the vacuum drum 23. As shown in Fig 3, the radius R^, of the vacuum drum gear 35 is less than the radius R^ of the raised sections 36 of the vacuum drum. Hence, the surface speed of the sections 36 is greater than the speed of the gear 35. The radius R CG of the cutter drum gear 32 is greater than the radius R CD of the surface of the cutter drum 30. Hence, the surface speed of the cutter drum 30 is less than the speed of the gear 32. Therefore, as the rotation of the axle 34 drives both the vacuum drum 23 and the cutter drum 30 (via the gears 32, 35 and axle 31), the surface speed of the vacuum drum 23 is greater than the surface speed of the cutter drum 30. Typically, the radii R-^ and R CG are chosen so that the difference in the surface speeds of the vacuum drum and cutter drum is less than 10%. Therefore, as a cut label is transferred from the cutter drum 30 to the vacuum drum 23, the label tends to be stretched on to the vacuum drum 23 as the surface speed of the section 36 is slightly greater than the surface speed of the cutter drum 30. This difference in surface speeds helps to creasing or wrinkling of the label as it is transferred from the cutter drum to the vacuum drum. In addition, due to the rotation of the cutter drum being driven by rotation of the vacuum drum there is less likely to be variations in surface speed between the vacuum and cutter drums. Modifications and improvements may be incorporated without departing from the scope of the invention.

Claims: CLAIMS 1. Apparatus for conveying a flexible sheet of material comprising first and second movable surfaces adjacent to each other and adapted to transfer the sheet of material from one surface to the other surface, drive means to move the first movable surface and a drive coupling between the first movable surface and the second movable surface to move the second movable surface when the drive means moves the first movable surface in use, and wherein, the speed of the second movable surface is not equal to the speed of the first movable surface and the flexible sheet of material is transferred from the slower moving surface to the faster moving surface. 2. Apparatus as claimed in Claim 1, wherein the movable surfaces are continuous. 3. Apparatus as claimed in Claim 1 or Claim 2, wherein the movable surfaces are the curved surfaces of two cylindrical drums. 4. Apparatus as claimed in any one of the preceding claims, wherein the movable surfaces are a receiver surface and a feeder surface. 5. Apparatus as claimed in any one of the preceding claims, wherein the drive coupling comprises two co-operating gears, one gear coupled to each movable surface. 6. Apparatus as claimed in Claim 5, wherein the movable surfaces are cylindrical surfaces, the radius of the gear attached to the slower moving surface is greater than the radius of the slower moving surface and the radius of the gear attached to the faster moving surface is less than the radius of faster moving surface. 7. Apparatus as claimed in any one of the preceding claims, wherein the difference in speeds between the movable surfaces is less than 10%. 8. Apparatus as claimed in any one of the preceding claims, wherein the faster moving surface is the surface of a vacuum drum and the slower moving surface is the surface of a cutter drum and the flexible sheet of material is a label to be applied to a container.

Inventors: RENILSON IAN, RENILSON, IAN
Applicants: KHS CARMICHAEL LTD, RENILSON IAN, KHS CARMICHAEL LIMITED
Application year: 1993
Main classification: B65C9
IPC codes: B65C9