Patent GB-594528-A (GB)
Title: Improvements in or relating to stop mechanism for automatic machines such as sewing machines
IPC: D05B3/08
Filed: 1944-05-25
Abstract: 594,528. Sewing-machines. NEWTON, E. P. (International Button Hole Sewing Machine Co.). May 25, 1944, No. 10191. [Class 112] Starting and stopping; button-hole sewing machines.-In a machine having a predetermined cycle of operations, particularly a buttonhole sewing-machine in which the buttonhole cutter is actuated by the stopping of the machine, means are provided to prevent return of the stop mechanism to the stopping position, once it has been moved far enough to start the machine, before the end of the cycle; in the form described, the mechanism is automatically moved to the full running position, so as to be under control of automatic stopping mechanism, when it is moved far enough to start the machine. The buttonhole sewing- machine shown is driven by a belt 41 with fast and loose pulleys on the machine shaft and a belt-shifter carried by a stop-arm 45 which is fixed to a sliding and rocking shaft 46 spring- pressed to the stop position. The stop-arm is pressed downwards by a spring plunger 53 into engagement with a cam 52 on the main shaft, when in the stopping position, this cam serving to actuate the buttonhole cutter lever 61 before stopping the machine, as described in Specification 586,162; the cam-engaging part of the stop-arm is spring-mounted to absorb shock. The sliding work-clamp 18, 21, connected to the feet-nut 25, is opened by a lever 72 which has a depending latch 76 engaging a lug on the tail of the cutter lever 61 so that when the latter rises after cutting the buttonhole, during the stopping of the machine, the clamp is opened. The stop-arm 45 is moved to the left, to start the machine, by an arm 94 of a three-armed crank pivoted at 87 and actuated by a treadle 93 against the action of a spring 90; a finger 96 moving with the crank trips the latch 76 to allow the work-clamp to close. The stop-arm and shaft 46 are held in the running position by a spring-pressed pivoted latch 101, which has a lug engaging behind a collar 104 on the shaft, until this latch is tripped by an upward extension of a horizontal bar 110 which is reciprocated transversely of the machine by a cam on the main shaft but is spring-pressed to the left so that it normally does not engage the latch. At the end of the operation cycle of the machine a pivoted dog 131 on the feed-nut 25 moves the bar 110 to the right so that the latch 101 is tripped to release the shaft 46 to stop the machine; an arm 135 carried by the shaft 46 has a tooth 134 which engages a similar tooth on the dog 131 to depress the latter clear of the bar 110. In order to prevent the stopping of the machine soon after starting, by release of the treadle before the shaft 46 is moved far enough to be held by the latch 101, the treadle is connected to the three-armed crank through a spring 141 and movement of the crank is resisted by a cam 142 engaging a spring-mounted cam member 143 ; the cams are arranged to have moved clear of each other when the mechanism has moved far enough to start the machine, so that their resistance then ceases and the extended spring 141 throws the mechanism into full running position.