Patent GB-1281875-A (GB)
Title: Improvements in or relating to apparatus suitable for use in joining two portions of sheet material
Inventor: HALL DENNIS SIDNEY
IPC: B29C65/00
Filed: 1968-09-24
Abstract: 1281875 Seaming non-metallic sheet material BRITISH UNITED SHOE MACHINERY CO Ltd 23 Sept 1969 [24 Sept 1968] 45251/68 Heading B5K In apparatus for joining two portions 20, 22 of sheet material, the portions 20, 22 are received and clamped with edge portions thereof in alignment with one another and with surface portions thereof adjacent the edge portions in contact with one another, the portions 20, 22 are then oriented to separate the contacting surface portions thereof and to bring the edge portions thereof into a relationship in which the two portions are to be joined, and, thereafter, the two portions, in this relationship, are presented to joining means. The apparatus is used for forming a back seam between two quarter portions 20, 22 of a shoe upper made from fabric coated with thermoplastic material and comprises two similar operating heads (12), 14, Fig. 1 (not shown). The head 14 comprises a first presser member constituted by an inner form member 16, Figs. 2 and 7, having two parti-cylindrical work supporting surfaces 24, 26 meeting at a curved ridge 25. A further presser 162, in the form of a block coated with a rubber layer 163, is shaped complementarily to the member 16. To effect joining of the portions 20, 22, the member 16 and the presser 162 are connected to a high frequency generator (not shown) so as to act as electrodes. The generator is connected to both heads (12), 14 and includes an alternating oscillator arrangement whereby the heating circuits of both heads cannot be tripped at one time. A first clamp assembly 28 comprises two clamp surfaces 80, 86, Fig. 3, on plates 72, 74 between which the portions 20, 22 can be received and clamped with edge portions thereof in alignment with one another. The assembly 28 is mounted for pivotal movement between a quarter portion receiving position, Fig. 2, in which the plates 72, 74 extend forwardly and a quarter portion releasing position, Fig. 3, in which the plates 72, 74 extend downwardly. A second clamp assembly comprises two clamp arrangements 100, 102, Figs. 3 and 4, each arranged to clamp one of the portions 20, 22. The arrangements 100, 102 comprise pivoted support blocks 104, 106, arms 122 having inner clamp members 124, and outer clamp members 130 to clamp the portions 20, 22 against the members 124. The arrangement is such that, as the first clamp assembly moves to its portion releasing position, the portions 20, 22 clamped thereby are transferred into the arrangements 100, 102. Apex portions 128 of the members 124 are provided whereby separation of the portions 20, 22 clamped by the assembly 28 is initiated during transfer to the portion releasing position, Fig. 3, this separation being completed after clamping of the portions by the second clamp assembly and the subsequent release thereof by the assembly 28. The second clamp assembly is movable between a portion receiving location, Fig. 5 (not shown), at which the portions 20, 22 can be received from the assembly 28, and a portion releasing location, Fig. 6 (not shown), at which the portions 20, 22 are positioned with their edge portions in abutting relationship in which the portions 20, 22 are to be joined by a butt seam. When the arrangements 100, 102 are moved to their portion receiving positions, the portions held thereby can be located against the surfaces 24, 26 of the member 16. The apparatus also comprises two clamp pads 144, Fig. 3, by which the portions 20, 22 located against the surfaces 24, 26 can be clamped against these surfaces to ensure that they are held in position during the movement of the member 162 into engagement therewith. In operation, the operator positions the portions 20, 22 in the assembly 28 and causes the portions 20, 22 to be clamped thereby. The portions 20, 22 are transferred, during pivotal movement of the assembly 28, into the arrangements 100, 102 which then clamp the portions which are released by the assembly 28. The pads 144 are moved into engagement with the portions lying against the surfaces 24, 26 of the member 16. The member 162 is lowered and joining is effected. A pneumatic circuit for the operation of the head 14 is described, Fig. 8 (not shown).