Patent GB-1202854-A (GB)
Title: Hemming and button sewing module
IPC: D05B3/14
Filed: 1969-03-12
Abstract: 1,202,854. Sewing machines. SINGER CO. 12 March, 1969 [18 March, 1968], No. 13152/ 69. Heading D1G. A sewing operation is performed on a work piece with one side thereof facing upwardly, as said piece is passed along a prescribed line of feed, the piece is turned over as the piece is passed alone the line of feed, and the second sewing operation is performed on the piece with the other side thereof facing upwardly, as said piece is passed along the line of feed. As described, a shirt front is hemmed with its inner surface facing upwardly and its tail end leading, the front is turned over to position its outer surface upwardly and its collar end leading, and buttons are sewn successively at spaced positions along the hemmed edge. Apparatus 20 for carrying out the operation comprises a hemming unit 24 associated with a work-supporting surface 44, and a buttonsewing unit 30 associated with a work-supporting surface 46 located below surface 44 and separated therefrom by a gap 56. A horizontal arm 144, having an upper surface level with surface 44 and a lower surface slightly above surface 46, is rigid with the piston rod of an air cylinder 142, arm 144 being normally positioned contiguous to surface 44 by the extended piston rod. Surfaces 44 and 46 are provided with respective vertical and aligned guide plates 52 and 54. A shirt front 80 is fed into unit 24 with the tail end 120 leading, the edge being folded upon itself in advance of a sewing machine 88 by a scroll guide 82. A resilient finger 144, carried by the piston rod 106 of an air cylinder 102 is adapted to be lowered for engaging the work adjacent the inner edge of guide 82. Compressed air is blown laterally into guide 82 from a pipe 92, and is also blown along surface 44 in the direction of work feed from a series of apertures formed in a pipe 94a positioned angularly on surface 44 in advance of machine 88. The latter is started when the leading edge or tail end 120 obscures a photocell 74. As the hem is sewn, the tail end 120 reaches the gap 56, and is urged downwardly therethrough by a momentary blast of air from a tube 122. Machine 88 continues to operate after the trailing edge or collar end 150 of piece 80 uncovers photocell 74 until the trailing end is located 'beneath the presser foot 118. When the next piece 80 obscures photocell 74, an auxiliary feeding wheel 126 of machine 88 moves the first piece 80 sufficiently to uncover a photocell 76, whereby an impact cutter 128 is actuated to sever the thread chain. An air cylinder 134 is also energised to extend its piston rod carrying a plate (130, the latter thereby clamping piece 80 at surface 44, and also actuating a switch 138 to energise cylinder 142 for retracting arm 144 and to move a carriage 146, rigid with arm 144, along a rod 148. Piece 80 is thereby laid on surface 46 upside down and with the collar end 150 leading. When a bar (152) rigid with carriage 146 actuates a switch 154, a plunger 156 is moved downwardly to clamp piece 80 against surface 46, compressed air is supplied to a plurality of nozzles (160) directed along surface 46 in the direction of work feed, and a feeding assembly 28 is actuated. Assembly 28 comprises a bracket 162 having an arm carrying a switch 166 and an air cylinder 168. A frame 170, journalled on bracket 162, journals a loose pulley 178 connected by an endless belt 176 to a driven pulley 174 journalled in bracket 162. Normally, pulley 174 is stationary and compressed air from cylinder 168 issues from a nozzle 182 to strike a plate 180 rigid with frame 170 to maintain the latter substantially horizontal. When switch 154 is actuated, pulley 174 rotates and, after a time delay, air to cylinder 168 is shut off, allowing frame 170 to pivot downwardly, whereby plate 180 pushes nozzle 182 into cylinder 168, and also actuates switch 166 to effect raising of plunger 156, while belt 176 then feeds piece 80 towards unit 30. The latter comprises a button-sewing machine 190, a button-feeding device 66, and a work-feeding device generally as described in Specification 1,128,780 and comprising an intermittently-rotated drum 196 and means for clamping the leading edge of piece 80. When the leading edge of piece 80 obscures a photocell 78, the supply of air to jets (160) is shut off, rotation of pulley 174 ceases, supply of air to cylinder 168 is resumed to raise frame 170, and a bar clamp (194), associated with device 64, is actuated to clamp the leading edge against drum 196. The latter then turns by a predetermined amount to the first sewing position, whereby a switch 198, initially held in deactivated position iby a cam 200 on drum 196. is activated to shut off air to a cylinder 202 for permitting descent of a work guide 212. The folded-over edge of piece 80 is guided to the sewing position between an inverted thannel section member 208, pivoted at 214 to the end of plate 54, and a plate 206 positioned on surface 46. Unit 30 is arranged to sew a succession of buttons 226 automatically at spaced positions. The buttons are transferred by a member 224 from the feeding means 66 to the jaws 220 of a button clamp. Jaws 220 are connected by a linkage to a bar 254 which thereby reciprocates as the jaws open and close. The arrangement is such that when a button is clamped between the jaws, the upturned end of bar 254 is positioned adjacent the actuating element 258 of a switch 256, but that if the jaws close with no button therebetween, bar 254 engages element 258 to actuate switch 256 to open the circuit of and shut down the apparatus 20. After the last button is sewn, a cam (264) on drum 196 actuates a switch to effect delivery of air to a stationary tube 266 so positioned as to assist transfer of the completed piece to a stacker 36. A cam (260) on drum 196 then actuates a switch to start the stacker motor 262, the latter being automatically stopped on completion of a stacking operation. Drum 196 is stopped when cam 200 de-activates switch 198.