Patent GB-973558-A (GB)
Title: Auxiliary power device for the operating of the adjusting members in sewing machines
IPC: D05B69/28
Filed: 1963-10-18
Abstract: 973,558. Sewing machines. DURKOPPWERKE A. G. Oct. 18, 1963 [Oct. 24,1962], No. 41342/63. Heading D1G. In a sewing machine a member such as a starting lever, presser foot or work clamp is operated by a compressed air motor controlled by valve means operated manually or automatically. Fig. 2 shows a diagrammatic arrangement in which the work clamp and starting lever of a group stitch machine are controlled by a single lever. Switching on the driving motor of the machine is also adapted to open a valve 7 to supply air via open valves 8 and 9 to a motor 10 for opening the work clamp. Partial depression of a control lever P serves to close valve 8 to reenergize motor 10, whereby the work clamp is closed by spring means. Full depression of lever P additionally opens a valve 11 to supply air to a motor 12, whereby a lever 13 associated with the latter actuates the starting lever and also closes valve 9. On release of lever P, valve 11 closes to de-energize motor 12 and valve 8 opens. The piston rod 12<SP>1</SP> of motor 12 is made telescopic to allow the piston to be returned to its initial position by spring means, while allowing lever 13 to hold valve 9 closed. Upon completion of the group of stitches the starting lever returns to its off position and valve 9 thereby opens. In a modification the valves 8, 11 are magnetically controlled and are operated in succession by a stepping switch. Fig. 18 shows a practical embodiment of the arrangement of Fig. 2. The machine is mounted on a table top 59. The under surface of the latter carries two identical brackets 36 supporting the motors 10 and 12 respectively, and two identical inverted U-shaped brackets 60 supporting valve 7 and the valves 8 and 11 respectively. A shaft 61 journalled in in the first bracket 60 is adapted, when actuated by a hand lever 63, to open valve 7 via a cam 62 and to open the starting switch 64 for the driving motor 65 via a convertor 66. A shaft 61 journalled in the second bracket 60 is connected by a crank 70 and link 78 to a treadle, actuation of which thereby serves to close valve 8 and open valve 11 in succession via cams 79 and 81 respectively. The piston rod of motor 10 is connected via a telescopic link 5 to one arm of a bell crank lever H pivoted on the bracket 36, the other arm being connected by a link 46 to the work clamp. The piston rod of motor 12 is connected by a similar link 5, bell crank lever H and link to the starting lever of the machine. Valve 9 is mounted on the bracket 36 supporting motor 12, and is adapted to be closed on energization of the latter by a cam rigid with the associated lever H. Fig. 4 shows a diagrammatic arrangement in which the work clamp and starting lever of a group stitch machine are automatically controlled. As in the previous arrangement, switching on the driving motor also opens valve 7 to energize a work clamp-opening motor 22 via a magnetic valve 20 and a valve 21. A work piece approaching the machine on a conveyer affects a photo-electric cell F to cause closure of valve 20 for de-energizing motor 22. A cam 24 on the piston rod 23 of motor 22 thereupon co-operates with a roller 25 on a lever 26, 26a for momentarily opening a valve 27 to energize a motor 28, whereby a lever 29 associated with the latter operates the starting lever and closes valve 21, the telescopic piston rod of motor 28 permitting lever 28 to remain in the valve-closing position. The practical embodiment is similar to that shown in Fig. 18, a first bracket 36 carrying the motor 22 and the valves 20 and 27, a second bracket 36 carrying the motor 28 and the valve 21, and a single bracket 60 carrying the valve 7. In the arrangement shown in Fig. 5 a work clamp 31 is operated by a double-acting motor 30. Actuation of a treadle P 2  in the direction P 3  serves to open a valve 33 for opening the clamp. Actuation of treadle P 2  in the direction Pf serves initially to open a valve 32 for closing the web clamp, and then to open a valve 34 for energizing a motor 35 to actuate the starting lever.