Improvements in or relating to apparatus adapted for use in forming a seam between two portions of sheet material

1,131,711. Folding edges of and seaming non- metallic sheet material. BRITISH UNITED SHOE MACHINERY CO. Ltd. 20 Jan., 1966 [23 Jan., 1965], No. 3090/65. Heading B5K. Apparatus for use in forming a back seam between edge portions of two quarters 24, 84 of a shoe upper 26 comprises a forming block 4 having two convex curved surfaces 18, 20 inclined to one another and meeting along a curved ridge (16), Fig. 7 (not shown), means 22, 68 for locating the quarter 24 on the surface 18 with an edge portion (25), Fig. 3 (not shown), projecting beyond the ridge (16), means 30 to wipe the portion (25) over the ridge (16) so that it overlies the surface 20, means 90, 92 for locating the quarter 84 on the surface 20 with an edge portion overlying the wiped over portion (25), and means 118 for pressing the edge portions of the quarters 24, 84 together against the block 4. The locating means for the quarter 24 comprises a gauge 22 mounted on a rack 38 slidably mounted in a fixed guide block 46 and a pivotally mounted silicone rubber clamp pad 68 arranged to move towards and away from the surface 18. The locating means for the quarter 84 comprises gauge members 90, 92 each pivotally mounted in a slot 86 on a portion 66 of a bracket (64) carrying the clamp 68. The wiping means 30 comprises flexible fingers 54 and is mounted on a rack 40 slidably mounted in the block 46. The racks 38, 40 are engaged by a splined portion 47 of a shaft 32 which extends through the block 46 and a second block (31), Fig. 9 (not shown). A second splined portion (49) of the shaft (32) engages with a rack (34) in the block (31), which rack (34) is operated by a pneumatic cylinder (36). The pressing means comprises a silicone rubber clamp pad 118 comprising concave curved surfaces (105), (107), Fig. 3 (not shown), meeting along a curved line (109) and which is mounted on a cross plate 116 secured by two insulators 114 to a cross plate 112 seucred to a block 110 slidable in a fixed guide block 106. The arm (117), Fig. 10 (not shown), of a lever (120) is mounted in a slot (115) in the block (110). The lever (120) is pivotally mounted on the block (106) and the second arm (119) thereof is secured to the piston of a pneumatic cylinder (124) pivoted on the machine frame. In operation, the operator positions the quarter 24 of plastic coated fabric on the surface 18 so that its fabric surface lies against the surface 18 and with a skived edge portion (25), Fig. 3 (not shown), thereof extending past the rid