Patent GB-191227631-A (GB)
Title: Improvements in or relating to Sewing Machines.
Inventor: TOPHAM LAURENCE ELMER
IPC: D05B15/04
Filed: 1912-04-13
Granted: 1913-02-27
Abstract: 27,631. Topham, L. E. April 15, 1911, [Convention date.]. Sewing - machines, lock-stitching by hooks. - A rotary hook-ring 151 with an inwardlydirected loop - taking point 152 is mounted to rotate below the workplate 1 in a plane inclined both to the workplate and the axis of the hook needle 100; the hook needle also being mounted below the work - plate a n d arranged to enter holes previously made in the work by an awl, and draw down loops of thread into the path of the hook - point. The hook is caused to rotate three times during one reciprocation o f t h e needle, and to avoid its fouling the needle, the race supporting t h e hook is oscillated in time with the movement of the needle. The hook-ring is mounted in a race formed in the edges of plates 154, 155 secured upon a bracket 156 which is pivoted u p o n two stationary pins in line with the universal joint 161. A hole 158 is cut in the plates for the passage of the needle. Bevel teeth 160 on the hookring mesh with a driving-pinion 159 having a lengthened boss which is mounted upon a pin in the bracket 156 and is connected to an extended boss of a pinion 162 bv the universal joint 161. The pinion 162 is driven by a wheel 122, three times as large, secured upon the main shaft 123. TEe bracket 156 is oscillated by means of a link 167 pivoted to an arm 166 projecting from t h e outer ring 164 of a pair of gimbals. This ring is pivoted to the frame about an horizontal axis so as to be free to oscillate and thereby reciprocate the link 167 under the influence of the inner ring 168 which is pivoted within the outer and is held in contact with and thereby wobbles with a flat oblique shoulder on the boss of a crank 170, which rotates with the needle-driving crank 120. The spool-case 174 is mounted upon a race-plate 176, secured obliquely upon the hook-ring and is held from rotation by the successive engagement with recesses 179 of pins 178 carried by a plate 180 fixed above the spool-case and parallel with the motion-plane of the hook-ring. The wall of the spool-case is cut away at 177 and a slot 204 opens into the spool-cavity. The spool thread passes through the slot to a guiding-eye 210 and thence to the stitching point. Adjacent to the slot, the thread is pressed upon by the upturned part of a spring 207, the semicylindrical end 208 of which is mounted in the spool-case wall and may be turned, to vary the thread tension, by a screw 209. The loop-taking point 152 of the hook-ring projects beneath the spoolcase and one arm of the thread-loop engaged lies in the groove between a pair of projections 186, 187 which are sufficiently high to extend the loop to a greater width than the depth of the spool-case. The spool 189 is held in position by a plate 192 roughly pivoted in a slot in the centre-pin 190 and pressed upon by a spring 196 which turns it upon the pivot so that the part 193 bears upon the spool. A rod 197 is used to eject the spool; it is moved upwards by a pinion 200 which engages rack teeth upon it and is rotated through a universally-jointed coupling-shaft by a thumb-wheel mounted in the frame. Needles, driving.-The needle-bar 101 is joined by a link 107 to one arm of a bell-crank lever 105, the other arm of which is connected by a link 110 to one arm 114 of a cam-actuated lever. In the position shown, the link 110 is in line with the arm 114.