Patent GB-107384-A (GB)
Title: Improvements in or relating to Sewing Machines.
IPC: D05B3/06
Filed: 1917-06-18
Abstract: 107,384. British United Shoe Machin ery Co., (Assignees of Hill, G. S.). June 19, 1916, [Convention date]. Button-hole sewing-machines.-In a button-hole sewing-machine in which the hole is cut after the stitching is completed, the mechanism is controlled by cams on a shaft 72, Fig. 3, which is driven by gears 70, 272 from a shaft 270, Fig. 8. The shaft 270 is driven rapidly by the band-wheel 276, Fig. 3, to place the work in stitching position, is then unclutched, and is then driven slowly and continuously during stitching, from the shaft 16 through a vertical shaft 318 and one-way clutch. The shaft 16 is then stopped and the clutch of the band-wheel 276 is thrown in to drive the shaft rapidly to restore the work to initial position and cut the button-hole, and the machine is then stopped. In starting the machine, the lever 298 is depressed to rock a shaft 296, Fig. 8, to which is secured a latch lever 292 which retains a spring- controlled lever 286, secured to a pivot pin 370, by the engaging lugs 290, 294. The clutch which connects the shaft 270 with the band wheel 276 is thus thrown in and the shaft rapidly rotated till the work-carrier is in stitching position. At this point, a cam 456 on the control cam-wheel rides under the tail 380 of a lever 368 pivoted on the pin 370 and moves back the clutch lever 286 by the engagement of lugs 408 and 410, thus throwing out the clutch of the band-wheel and snapping the lever behind the latch 290. The lever 368 carries a spring plunger 366 which coacts with a stop-cam 358 mounted under spring-control on a clutch member 336 secured to the shaft 16, which actuates the sewing mechanism and is driven by a band-wheel 338 forced into engagement with the clutch member 336 by a. spring 342 and held off by sliding pins 344. an antifriction washer 346, and a loose disk 348 having cam surfaces 350 coacting with cam-surfaces 352 on a fixed disk 354 the position of which is adjustable by a shaft 356 and worm-gearing. The stop-cam 358 comprises an eccentric braking surface and a recess into which the plunger 366 drops to stop the shaft 16. When the lever 368 is rocked by the cam 456, the plunger moves laterally out of the recess on the stop-cam, and is moved forward by its spring so that an abutment 394 on an arm 392 carried by it releases a spring-pawl 396 by which the camdisk 348 is held and allows the clutch of the shaft 16 to be thrown in. The stitching proceeds till the tail of the lever 368 falls off the cam 456 and the lever is actuated by a spring 400 into the path of the stop-cam, the plunger 366 riding over the eccentric braking surface thereof and being pushed in against the action of its spring. This movement of the plunger 365 causes the hook 404 on the arm 392 to engage a projection 406 on the cam-disk and turn it to throw out the clutch and engage the holding pawl 396. The plunger is then projected forward into the recess of the stop-cam. The sideways and in and out movement of the stop plunder in stopping the shaft 16 causes an arm 412 carried by it to engage under and move a spring controlled hooked arm 414 on the latch lever 292 and thus release t.he clutch lever 286 which throws in the clutch of the bandwheel 276 which then drives the shaft 270 during the return of the work to the button-hole cutting and initial position. The machine is then stopped by a cam 420 on the control cam-wheel actuating the clutch lever to throw out the clutch and snap the lever behind the latch 290. The stopping position of the cam is determined by a dog 432 engaging a lug 424 on the control cam, and released on starting the machine by a headed rod passing through an aperture on an extension 426 of the latch lever. A similar dog is provided to engage an abutment 434 on the leading end of the cam 456 to prevent over-running of the cam-shaft when the high-speed clutch is thrown out. This dog is released bv a rod 430 having a bent end actuated by the outward movement of the arm 412 when the stop-plunger is moved to throw in the clutch of the shaft 16. The control cam is made adjustable for different sizes of buttonhole, and also the gearing between the shafts 16 and 270 for different spaces between the stitches. The tension of the needle-thread is released at the end of a stitching operation by a rod 444, Fig. 6, which is acted on by an arm 446 on a sleeve secured to a rock-shaft 448. The rockshaft 448 also carries an arm 450, Fig. 8, in which is mounted a spring-controlled transverse pin 452 which at the end of an operation overlies the arm 412 of the stop-plunger and holds the rod 44:4 in its forward position releasing the tension. When the stop-plunger is moved laterally in starting the stitching mechanism, the arm 450 is released and the tension applied to the thread. Specifications 117,268 and 117,269 are referred to. The Specification as open to inspection under Sect. 91 (3) (a) comprises also the following subject-matter :- Button-hole sewing-machines. - The workclamping devices are carried by a frame 150, Fig. 10 (cancelled), which is pivoted on a sliding block 158, and is reciprocated lengthways of the buttonhole by a cam-actuated rod 164 supported by a swinging arm 168. Lateral movement is imparted to the frame about its pivot during the stitching of the eye by a cam-actuated lever pivoted on a vertical axis. The lower clamping members 180, Fig. 31 (cancelled), are formed on plates 182 which are pivoted to a plate 178 secured to the posts on the frame 150 and are held in position by spring catches 192 and provided with spreading cams 246 adapted to engage with cams 244 on the buttonhole cutting device. The upper clamping-members 186 are carried by arms 188 which are pivoted in blocks 190 secured to the plate 178 and are provided with extensions 208 engaged by resilient extensions 206 of two rearwardly extending arms 205 of a rock-sleeve mounted on a stud 202. The sleeve is acted on by a spring 210 to hold the clamps open and is actuated by a cam 212 engaging the arm 214 to close the clamp. The cam is formed on one arm of a lever pivoted on a stud 216 secured in the frame 150. The other arm of the lever has a projecting pin adapted, when the frame is in the rearward position, to enter a notch in a spring-and-stop controlled lever carried by one end on the bell-crank lever 226 which is actuated by the cam-shaft. The clamp is closed when the machine is started and is so held by the concentric part of the cam 212 until the frame returns to its initial position, when the cam is again actuated to release the clamp. The button-hole-cutting mechanism comprises a die 234 clamped in the upper part of a block 236 secured to the turret bracket 84, chip passages 240, 242 being provided. The movable member comprises a block 248, which is provided with a spring-pin for clearing the chip passage and is secured to the end of an arm 250, normally held up by a spring 258. A lever 254 is actuated by a cam 260 on the cam shaft and contacts with an adjustable screw 256 on the arm 250 to cut the button-hole. The rotary needle-head 46 and looper-supporting turret 82 are rotated through bevel gears by shafts 56, 76 actuated by segmental racks 60, 64 connected together by a link 62. The lower rack has an arm 66 which is actuated by a cam on the camshaft 72. Needles, vibrating laterally; loop-stitching. - The stitch-forming devices comprise a laterally vibrating needle, and rotary needle and looper supports. The lateral vibrations of the needle are obtained by surrounding the needle-bar by a sleeve 6, Fig. 10 (cancelled), which is reciprocated in the rotary head and is connected thereto by a link. The sleeve is reciprocated at half the speed of the needle-bar by a bell-crank lever 26 and eccentric rod 28 having a strap embracing an eccentric on the shaft 16. The looper mechanism comprises a threaded looper 86, Fig. 18 (cancelled), and an unthreaded looper 88 carried by arms 90 of a carriage pivoted on the shaft 96 across the top of the turret 82. The carriage is rocked by a link 102 ball-jointed to a sleeve 100 which is balljointed at its lower end to one end of a lever 104, Fig. 10 (cancelled). This lever is actuated by a link 106 with a yoke 108 embracing a three-cornered cam on the shaft 16. Co-operating with the loopers and adapted to overlie them are two spreading fingers 114, 116 which are carried by a frame pivoted at right-angles to the shaft 96. This frame is rocked by a link 124 ball-jointed to a hollow rod 126 which passes through the sleeve 100 and is ball jointed at its lower end to a lever 128 which is actuated by a rod 132 having a strap embracing an eccentric on the needle-actuating shaft 10. The shaft 10 rotates at twice the speed of the shaft 16 so that the needle makes a complete stitch in the body of the material and in the button-hole slit alternately, and the spreaders are rocked twice for each to-and-fro movement of the loopers. Threads controlling otherwise than in stitchforming.-Means are provided for releasing the tension of the needle thread at the completion of the sewing and restoring it at the beginning of the next operation. The outer disk 144, Fig. 6, of the tension device is pressed against the inner disk by a rod 438 and a spring and adjustable nut 440, and is released by a rod 444 actuated by the stop mechanism at the close of an operation. Frames.-The upper part of the machine frame is hinged to the bed-plate about the bearings of the shaft 270, and to prevent or brake accidental dropping of the frame when raised it is provided with a ring 490, Fig. 39 (cancelled), having a oneway clutch connexion 496 with a ring 488 which is surrounded by a brake-hand 486 secured to the bed-plate. This subject-matter does not appear in the Specification as accepted.