Patent GB-1365350-A (GB)
Title: Sewing machine with work piece feeding device
IPC: D05B23/00
Filed: 1971-12-22
Abstract: 1365350 Sewing machines BROTHER KOGYO KK 22 Dec 1971 [24 Dec 1970 25 Dec 1970 26 Dec 1970] 59743/71 Heading D1G A sewing machine includes a workpiece feeding device which positions workpieces below the presser foot of the machine for subsequent stitching to a garment, the sewing machine comprising a horizontally movable presser foot 10 which moves the workpiece relative to the reciprocating path of the needle 7 said presser foot being spring urged downwardly to grip the workpiece, the feeding device comprising a feed plate 47 movable by a piston 37 of a pneumatic piston and cylinder 32 between an inoperative retracted position where it is loaded to a position below the lifted pressure foot, the retraction taking place when the presser foot has been lowered to grip the workpiece against the withdrawing force of the feed plate 47. As shown the feeding device comprises a stand 18 with a support plate 20. The actuating mechanism 26 is hinged at 25 to the support plate 20 and is supported at its other end on an adjustable spring 29 which allows for a slight vertical movement of the feed plate during its horizontal movement. The feed plate 47 is fixed through a plate 45 and a block 44 to the end of a piston rod 37 of the pneumatic actuating device 32. A workpiece is placed on the plate 47 between fixed guides 49 and is held down by a clamp 64, actuated by a control knob 60. In operation the presser foot is lifted by a solenoid and the piston rod 37 is withdrawn to the loading position. A blocking member 57 actuated by control 60 abuts the end of a guide plate 50 and this causes the actuating member 51 to remain stationary. A pin 63 on one arm of the clamping member 64 engages a slot 62 in the member 51 and causes the clamp 64 to open by rotation about a pivot 67. The workpiece is then position on feed plate 47. The control knob 60 is turned then to release the blocking member 57 and by allowing movement of the member 51 causing the clamp 64 to grip the work-piece. A switch 68 is operated at this time to cause a current of air to blow the finished workpiece from the throat plate of the sewing machine and a fresh workpiece is then applied. The piston 37 then moves the feed plate 47 forward and a timer in the electrical control circuit retains it in the forward position for a predetermined period. The presser foot lifting soleoid is then de-energised and the presser foot is spring urged downwardly to hold the workpiece, the presser foot being provided with a slot 77 to allow it to pass over the clamp 64. When the timer completes its period the piston 37 is retracted and the feed clamp 47 is pulled out from under the workpiece, the spring being sufficiently strong to overcome the drag exerted on the workpiece by the clamp 64. The clamp is turned again to the open position as it is retracted by the action of the actuating rod 51 and lock member 57. The motion of the presser foot to follow the contour of sewing required is described in known manner from a cam. The presser foot being shaped, in plan view, as shown in Fig. 9, the sewing operation commencing in the slot 78 and following the outside contour of the presser foot. A quick return mechanism is provided to move the presser foot back from the finishing position to the starting position at the end of the cycle.