Patent GB-190321476-A (GB)
Title: Improvements in Button Hole and like Machines
Inventor: HARMON FRANK LESLIE
Filed: 1903-10-06
Granted: 1904-09-22
Abstract: 21,476. Harmon, F. L. Oct. 6. Buttonhole-sewing machines ; buttonholes, cutting.-The invention relates to a machine which cuts and stitches a buttonhole in the manner shown in Fig. 42. The buttonhole is shaped so that the edges are partly parallel, partly diverging, and partly round. The stitch employed is an overedge doubleloop stitch with two threads which is the one shown in Fig. 42, or else a stitch of the same nature but with three threads. The requisite movement comprises one or more of the following: - An oscillatiou of the work-plate D, Figs. 4 and 35, about a pivot d, a rectilinear movement of the pivot d, and a rotation of the needle, loopers, and other stitch-forming devices about a fixed vertical axis. The movement of the pivot d is effected by a block d' which carries the pivot and slides in a slot in a fixed table A. The block is connected to a pin d<2> which is acted on by a spring d<6> and also by a cam K. The table also has a slot D<1> parallel to the former one in which there fits a block m<2>, Fig. 15. This block is mounted adjustably on a lever m<1> so as to suit buttonholes of various sizes. The lever turns on a fixed pivot and is acted on by a spring m<9> and a cam-face M. This cam thus affects the swinging movement of the plate D about the pin d. The adjustability of the block m enables buttonholes of different widths to be sewn without adjusting the needle. The rotation of the stitching mechanism is effected by mounting the needle and looper bars on a yoke B shown separately in Fig. 25 and partly shown in Fig. 15. The journals b, b<1> of this yoke are hollow; the lower one turns in a fixed support m<8>, while the upper one turns in the overhanging arm of the frame. The cams K, M together with a cam k<10> and ratchet teeth J are all carried on the support m<8> on which are also mounted two rings k<1>, k<2>. The former of these carries a pawl m<14>, Fig 3, which actuates the ratchet J and turns the cam-wheel. It also carries a sliding block k<7> which is moved inwards in opposition to a spring k<11> by the cam k<10>. This block also carries an adjustable plate k<8>. The ring k<2> has a protecting arm to which is connected a rod k<3> for oscillating it from the main shaft by pin-and-slot gearing. The arm also carries an adjustable screw k<6> and a fixed projection k<9>. The ring is influenced by a spring B<2>. During the sewing of the straight parts of the buttonhole, the pawl ring k<1> is actuated through the screw k<8> which strikes the block k<7>. The adjustment of this screw governs the throw of the pawls, and the consequent number of stitches made in these parts of the buttonhole. By the time the circular part is reached, the cam k<10> has moved the block k<7> inwards so that the pawls are driven by the engagement of the plate k<8> and the projection k<9> which are then nearer together than by the distance of the block k<7> from the screw k<6>. The feed for this part of the buttonhole is thus made to differ from that during the other parts, and the number of stitches is governed by the adjustment of the plate k<8>. When the circular part of the buttonhole is completed, the cam k<10> allows the block k<7> to move outwards again, and the feed proceeds through the screw k<6>. The camwheel is acted on by a band brake which prevents overthrowing, and by check pawls in a casing m<12>. The yoke B in the course of sewing the eye part of the buttonhole is turned round through a semicircle by a projection k<12>, Fig. 15, on the cam-wheel which engages a clutch h<12> on the yoke. During this motion, a strong spring B', connected with the lower hub of the yoke by a strap b<3>, is stretched, and when the motion is completed, the yoke is caught by a latch. The catch h<12> is also thrown off from the projection k<12> by a fixed stop h<13>, the camwheel continuing its motion. Fig. 3 shows the position just after this has occurred. The spring remains strained until the sewing of the buttonhole is concluded. In commencing to sew another hole, the material is moved so as to lie between two clamping-arms r<5>, r<6> and two plates r<1>, r<2> which slide between guides r on the work-plate D, and on which the arms r<5>, r<6> are respectively pivoted. These clamping-arms are acted on by a spring r<9> acting through a forked lever r<10> which also carries a distance-piece r<13>. The arms are kept elevated by a finger-piece r<11>, but when this is depressed, the clamping-arms fall on to the material. The latch which retains the yoke B against the action of the spring B' is released at the same time, and the yoke is moved back instantaneously through a semicircle. During this rotation, it engages a camplate h<4> on the work-plate D, and forces it back so that the material is placed under a cutter H which is carried on a lever h. This lever is then engaged by a projection h' on the yoke, and is actuated so as to cut the buttonhole. The yoke, still acting on the work-plate D, causes a fixed stop a<3> to act on inclined edges on the plates r<1>, r<2> which are thus separated so as to open the buttonhole. The distance-piece r<13> is then forced between the plates by the spring r<9>, and the buttonhole is thus kept open. The work-plate is then allowed to return so that the roller d<5> bears against the cam K, the buttonhole being then under the needles. Finally the yoke strikes a spring buffer which is then caught by a latch. In a modification, the camwheel is actuated by worm gearing instead of by pawls and a ratchet. A spring corresponding to B' is conneted to a rack which is operated by a cam on the cam-wheel, thus compressing the spring. This spring may be assisted by a weight. The yoke has a pinion engaging with the rack, which thus drives it. The rack-bar instead of the yoke strikes the buffer. Stopping-gear.-The buffer actuates a lever p which controls a driving-clutch on the main shaft p<10> through a clutch lever p<1>. The driving-clutch consists of a block fast on the main shaft having a spring pin which, when protruded, engages with a band pulley loose on the shaft. This pin is normally pressed back by the lever p<1>, so that when the lever is withdrawn from it by the action of the yoke, the clutch block and the loose pulley are connected and the machine is started. The cam-wheel releases the buffer latch when the buttonhole is finished, and the lever p<1> then disconnects the clutch. The clutch block is arrested in the proper position by a latch p<3> on the lever p<1>, and springs carried by the clutch block cause the machine to be started and stopped without shock. Double-loop stitching - machines ; loop-stitching machines; overedge-stitching machines; needledriving ; needle-holders; needles, setting ; worksupports.-The stitch is made upon an adjustable throat-plate N carried by the lower journal b<1>of the yoke, as shown in Figs. 4 and 43, by two loopers n<11>, n<13> and a needle n<12>. The needle-bar n<2> and the bar n<1> for the straight looper work in blocks N<2>, N<1>, Figs. 26 and 27, which are adjustably mounted in the parts of the yoke which lie across the journals b, b<1> as shown in Fig. 25. The adjustment enables the distance between the place where the needle enters the work and the edge of the buttonhole slit to be altered. The bars work in a plane perpendicular to that of Fig. 4, but are inclined to one another in this plane as shown in Figs. 26 and 27 so as to cross in operation. They are operated so as to slide in the blocks N<1>, N<2> by links n<7> having ball-and-socket joints at each end. The joints with the actuating-arms are as far as possible central with the journals of the yoke, so that the revolution of the latter does not interfere with the motion of the needle and looper bars. Besides the straight looper, the block N<1> carries an arm n<3> for the curved looper n<13> which passes between the needle and the straight looper. This arm is adjustably mounted on the block, and is actuated by a pin-and-slot connection from the straight looper bar. The needle-bar actuating-arm n<24> is pivoted at n<25> and is actuated by an eccentric on the main shaft. The looper actuating-arm n<8> is pivoted at n<20>, and has a slot n<9> shaped as shown in which there slides a pin carried by a pivoted arm n<14>. This arm is oscillated by a pin-and-slot connection from the main shaft. As before mentioned, the stitch may be made with either two or three threads. In the former case, the straight looper is forked, and the needle and the curved looper carry the threads. The curved looper passes through the needle-thread loop below the fabric. The looper thread is then caught by the straight looper which passes it through the buttonhole slit and over the edge of the work to the upper side, where it is engaged by the needle thread. In the threethread stitch, the straight looper has an eye through which a thread passes. The curved looper passes through a loop of needle thread and presents to the straight looper a loop which is engaged by the latter looper on the edge of the work. The straight looper then presents a loop of its thread to the needle which engages it above the work. The upper and under sides of this stitch are shown in Fig. 47. In the modification above referred to, the yoke is made tubular, and the curved looper is dispensed with. The under thread, which as before is carried to the upper side of the work by the straight forked looper, is presented to the needle by a loop spreader pivoted on the upper journal of the yoke and actuated by the needle-bar. The needle and looper both work vertically. Frames.-The machine frame W<1> is pivoted at W<3> to its fixed supports W so that the working parts underneath can be reached.