Patent GB-228504-A (GB)
Title: Improvements in or relating to shoe sewing machines
IPC: D05B15/00
Filed: 1924-05-12
Abstract: 228,504. United Shoe Machinery Corporation, (Assignees of Leveque, B. T.). Feb. 2, 1924, [Convention date]. Chain stitching; presser-bars with periodic control; needle-driving mechanism, disconnecting; starting and stopping gear; feed by awls.-A boot-sole sewing machine is provided with means for causing the presser-foot to be lifted a constant distance above the work, for varying the needle stroke in accordance with work-thickness, ing the presser-bar on stoppage. A block on the needle-bar 118 is connected bv a link 124 to a lever 126 pivoted at 128 to a lever 130. The lever 126 has a slot 134 engaged by a block 136 on an arm 138 which is moved by connections with the presser-foot as the work-thickness varies. When the axis of the block 136 is in alignment the pivot of the lever 130 the lever 126 and lever 130 will move as one, but when the axis is out of alignment the movement conveyed by the lever 130 to the lever 126 and the consequent movement of the needlebar will be increased or diminished. The lever 130 is latched by a latch 146 engaging a pin 148 to move in unison with a lever 140 oscillated continuously by a crank pin 120 on the shaft 104 engaging a cam slot 144 therein. The latch 146 is released to stop the needle-bar by means described below. The presser-bar 150 carries an arm 152 on which is a roll 154 engaging a cam-slot' 156 in the arm 138 which is thus moved in accordance with the position of the presser-bar. The slot 134 is so arranged that it is concentric with the axis of the arm 138 when the needle is at the bottom of its stroke and the lower limit of the needle stroke is therefore not affected. The presser-foot is pressed downwardly by a spring 158 and by a spring 160 surrounding a shaft 162 and adjustable as to tension by a worm and pinion 166, 168. which rotate a collar 164, the shaft 162 being connnected by an arm 170 and link 174 to the presser-foot bar. The presser-foot lifting device comprises a lever 182, Fig. 4, having a V-shaped edge which engages a notched block 178 pivoted to the presser-bar. The lever 182 is pivoted to an arm 184 cam-actuated from the shaft 104. The lever 182 is displaced to vary the lift of the presser-bar in accordance with the work-thickness by means comprising a lever 202 connected to the lever 182 by a link 204 and having a cam-surface 206 engaged by a roll 200 mounted on the block at the end of the presserfoot bar. The feed point 214 is adjustably held in a carrier 220, mounted on a block 172 on the presser-bar, by means of pins 224 engaging slots 226 in the carrier having horizontal and inclined portions. The actuating mechanism for the carrier in conjunction with these slots causes it to move to and from the work as well as in the direction of feed. This mechanism comprises a lever 230 connected to the carrier by a link 232 and having a slot 234 at its upper end which is engaged by a roll 236 on the lever 130. A spring 238 tends to move the lever 230 to hold the left-hand side of the slot in contact with the roll so that during the sewing operation the lever 230 is actuated by a lever 130. A lever 242, Fig. 1, is connected by a link 244 to an arm 246 projecting from the shaft 248 of the lever 230. A lever 250 connected to the control treadle is urged upwardly by a heavy spring to engage the tail of the lever 242 so that when the treadle is released at the close of a sewing operation the lever 242 is moved downwards and the lever 230 is moved so that the roll 236 bears against the right-hand side of the slot and on reaching the upper limit moves into a lateral notch of the slot while at the same time a stud 258 on the lever 230 engages the tail of the catch 146 and disconnects the lever 130 and accordingly the needle and feed mechanisms. The feed point reaches the limit of its feeding movement and the presser-foot descends while the needle is still continuing its upward stroke. The presser-foot is automatically raised when the machine is stopped by means comprising an arm 262, Fig. 6, connected to the rock shaft 162 which operates the presser-foot lifting mechanism. The arm 262 engages a snail cam 260 and is mounted so that it may be moved to one side out of engagement with the cam when the treadle is depressed during running, the means for effecting this comprising a link 268 connected to a lever 270 having an incline 274 engaged by a roll on a lever 278 mounted on the shaft 240. The automatic device may be put out of action by a pin 280 which is moved into engagement with the lever 270.