Patent GB-191208801-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: 8801. Topham, L. E. April 15, 1911, [Convention date]. Sewing - machines; governing needle thread. -In a machine having a hook-needle, a rotary hook making several revolutions during the formation of a stitch, and an oscillating takeup actuated by a continuously rotating crank, an auxiliary take-up is provided which is moved positively, first, to engage with the thread, and afterwards to co-operate with the main take-up in controlling the thread. The main take-up 253 is oscillated from the position shown in Fig. 5, where its roll 255 is free of the thread, to the extreme position shown in dotted lines in Fig. 5, and in full lines in Fig. 5 (cancelled), and carries with it the thread which lies between thread rolls 256, 257. The auxiliary take-up consists of a rigid thread finger 265 secured upon a shaft 266 which is actuated through a train of mechanism comprising bevelgearing, a shaft 267, link 270, lever 271, and cam-lever 173. The thread finger is actuated so as to permit a slight retraction of the thread loop before it engages the thread and afterwards it moves to give up thread to the looper mechanism in the threading of the needle. On its return movement, the main take-up engages and bends the thread between the finger 265 and the roll 257, and to compensate for this the finger is suitably actuated by its cam. The Specification as open to inspection under Section 91 (3) (a) comprises also the description of a complete wax-thread sewing-machine having the following improved parts, none of which subject-matter appears in the Specification as accepted. Lock-stitching by hooks.-A rotary hook-ring 151, Figs. 16, 24, 26, and 29 (cancelled), with an inwardly-directed loop-taking point 152 is mounted to rotate below the work-plate 1 in a plane inclined both to the work-plate and the axis of the hook needle 100 the hook needle also being mounted below the work-plate and 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 of the needle, and to avoid its fouling the needle, the race supporting the 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 upon two stationary pins in line with a universal joint 161. A hole 158 is cut in the plates for the passage of the needle. Bevel teeth 160 on the hook-ring mesh with a driving-pinion having a lengthened boss, which is mounted upon a pin in the bracket 156 and is connected to the extended boss of a pinion 162 by the universal joint 161. The pinion 162 is driven by a wheel 122, three times as large, secured upon the main undershaft. The bracket 156 is oscillated by means of a link 167 pivoted to an arm projecting from the outer ring 164, Fig. 23 (cancelled), 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-pane of the hook-ring. The wall of the spool-case is cut away at 177, Fig. 26 (cancelled), 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 semi-cylindrical 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 spool-case, and one arm of the thread-loop engaged lies in the groove between a pair of projections 186, 187, Fig. 29 (cancelled), 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, Fig. 16 (cancelled), is connected by a link 107 to one arm 105 of a lever, the other arm of which is connected by a link 110 to an arm 114 of a second lever pivoted at 116 and actuated by a crank on the undershaft. A dwell at the upper limit of the needle's movement is occasioned by the pin 106 uniting the ling 107 and the arm 105 passing slightly beyond the dead centre and an idle movement is occasioned at the lower limit as the pin 111 passes beyond the centre line of the arm 114. Perforating-devices; feed by awl.-A sliding awl-carrier 54, Fig. 5 (cancelled), is connected by a link 91 to an oscillating arm 94 on a shaft 95, having a second arm linked by a pitman to a rotary-crank. When the awl is at the lower end of its stroke, the joint 93 between the parts 91, 94 passes slightly beyond the dead-centre and thereby produces a slight idle movement of the awl equivalent to a dwell. The dimensions of the parts 91, 94 also are such that the awl is clear of the work throughout two-thirds of each cycle. The slide supporting the awlcarrier is mounted upon parallel swinging levers 56, 57, and a lever which is not shown, being in line with lever 57. The lever 57 and the one not shown are fixed upon a shaft 63 actuated directly by means of an arm 70, Fig. 8 (cancelled), upon the shaft, and a pitman 73. The pitman is pivoted upon a swinging link 77 shown in dotted lines and is actuated by a camgroove engaging the bowl 74. The link 77 swings upon the pin of a crank 79 on a shaft 80 and the feed is varied by rotating the crank. The crank centre is concentric with the extreme upper position of the pin, uniting the pitman and the swinging link, so that for all lengths of feed the awl will be brought to the same position at the end of each feeding movement. For adjustment of the feed the crank shaft has a second arm 82, prolonged to form a hand adjuster. The end of this arm is tubular and encloses a spring-pressed plunger rigidly connected to an outer tubular part 89. The plunger has a spiral rib 86 on its inner end which engages teeth cut in a fixed plate 87. If the part 89 be turned, a micrometer adjustment of the feed is affected by means of the spiral rib, and if the part 89, with the plunger, be pulled outwards, quick variation of the feed can be effected. Presser-bars, lifting automatically and non- automatically; presser - bar springs. - The presser-bar 3 is given a uniform lift from work of any thickness by means of a gripping lever 14, Fig. 5 (cancelled), mounted in a sleeve sliding upon the presser-bar and normally held upon the top of the presser-bar bearing-bracket 5 by a spring 11. The lever 14 is actuated through a link 19 and lever 17 on a cam oscillated shaft 18. The link 19 is made of two parts screwed together and its length can be adjusted after removing a pivot pin 20 normally held in place by a spring 21. Adjustment of this link varies the initial position of the lever 14 and, consequently, the lostmotion, before the presser-bar is gripped, and the height to which the presser is subsequently raised. The bar can be lifted by a treadlegear which comprises a spring-pressed sliding- rod 40, Fig 8 (cancelled), jointed to an arm on a shaft 37 having a second arm 34, Fig. 5 (cancelled). The end of the arm 34 engages between two laterally-projecting lugs on the top of the presser-bar. The presser spring is helical and situated concentric with the shaft 37 perpendicular to the presser-bar. One end 46 of the spring extends tangentially and presses upon the end of the arm 34 and the presser-bar. The other end is secured to a sleeve 47, Fig. 5 (cancelled), which is eccentric with the shaft 37 and may be rotated to vary the pressure of the spring upon the presser-bar by means of a worm on a hand-operated shaft 51. and worm teeth cut in the sleeve 47. Needles, hook, threading - devices for. - The needle is threaded by means of a thread finger 126, Fig. 5 (cancelled), and a thread-carrying looper 134. The former is secured upon a short vertical shaft mounted in the machine frame and oscillated through a crank and a link by a sleeve which is reciprocated axially upon the rock shaft 63 by means of a groove in a cam drum 24, the sleeve being further guided by an arm 132 upon it which engages a grooved plate 133. The eyed looper 134 is carried by a short vertical shaft 135 mounted in a frame 136 itself pivoted upon the machine frame at 139. The shaft 135 is oscillated in the frame 136 bv a link connexion with a second cam-actuated sleeve on the rock-shaft 63, and the frame 136 is oscillated by a short link connexion with a shaft 147 which is reciprocated lengthways by means of another groove in the cam drum 24. Governing needle thread.-The thread tension comprises a thread disk 212 situated between a fixed friction disk 215 and a movable friction disk 216 pressed towards the disk 215 by a spring 218 but periodically moved against the spring to release the tension by the endlong movement of a central rod 213 to which it is fixed. The rod 213 is jointed to a rod 220 pivotting upon a pin-point 221 and actuated by a ball-and-socket connexion with an arm of a shaft 225. Upon a second arm 226 on this shaft is pivoted a cranked-lever