Patent GB-198628-A (GB)
Title: Buttonhole sewing machines
IPC: D05B3/06
Filed: 1922-03-08
Abstract: 198,628. Fairweather, W., (Singer Manufacturing Co.). March 8, 1922. Button-hole sewing-machines. -The machine described in Specification 183,873 is reorganised so that it will operate to cut the buttonhole prior to stitching. Means operated by the relative movement of the stitch-forming mechanism and the work-clamp, are provided for unspreading and opening the work-clamp. Button-holes, cutting. Depression of the starting-rod 117, Fig. 1, connects a two-armed lever 18, 113 to a cam-groove in the continuously rotating pulley 109 which thereupon transmits a single to-and-fro movement to the lever in the known manner. As the arm 18 is depressed, a tooth 122 on a link 123, which is pivoted at 124 to the arm 113, is drawn forward and drops, under the influence of a spring 123<1>, in front of a shoulder on a lateral arm 126 of the usual controlling lever 106 for the cutter-shaft clutch. The tooth 122 is formed on a plate 127 adjustably fixed to the link 123. During the return movement of the arm 18, the tooth 122 pushes the arm 126 rearwardly, thereby shifting the lever 106 and its latch-plate 105 inwardly to clutch the cuttershaft 99 to the continuouslyrunning pulley 109 for one revolution. A cam 143 on the shaft 99 lifts a lever 145 pivoted to the machine-standard so that a lateral extension 145' thereof lifts the link 123 out of engagement with the arm 126. The usual cam on the hub of the driven disc 102 of the cutter-shaft clutch device restores the bellcrank-lever 106, 126 to initial position for arresting the rotation of the cutter-shaft. When the link 123 is lifted, the shoulder 150 of a spring-actuated latch lever 147, Fig. 3, swings underneath the link 123 to hold it in ineffective position, and an extension 151 of the lever 147 is positioned in rear of a pin 152 on the arm 126, blocking possible accidental movement of the lever 106, 126 to starting position during sewing. Actuating of feed. The usual rapid-feed and stitching-feed mechanism is employed, the rapid. feed shaft 36, Fig 5, being connected to the continuously-running shaft 39 by means of the usual endwise-movable rod 44 carrying the clutchoperating fork 46 and a lateral pin 45. A bellcrank lever 49, 48, continuously rocked by a crank 50 on the shaft 39, reciprocates bars 52, 53 which are normally held by latches 56, 60 against the action of springs 54, 58, Figs. 5 and 7. Just before the cutter-shaft is stopped, a cam 135, Fig. 1, on the disc 102 depresses a lever 136 fixed to a shaft 137. The lower end of a lever 138 also fixed to the shaft 137 engages with the slotted latch 60, Figs. 1 and 6. The depression of the lever 136 thus withdraws the latch 60, so that an abrupt shoulder 68 on the bar 53 engages with the pin 45 on the clutch-actuating rod 44 and pushes it to the right, thus starting the rapid feed to shift the work from cutting to sewing position. On the return motion of the bar 53, the inclined shoulder 69 thereon encounters the pin 45 which forces the bar 53 downward so that the latch 60 again engages therewith. When stitching position is reached, the cam-rise 85, Fig. 7, on the usual auxiliary cam-disc 38 fixed to the rapid feed shaft 36 initiates, through the members 81, 88, 89, 79, the shifting of the usual stop-motion lever 72 to running position, thus starting the stitch-forming. mechanism. The link 88, 89 is of toggle formation, so that by bending the toggle the starting- connection may be rendered inoperative. A spring- pressed pin 88a on the link 88 yieldingly engages in a recess in the member 89. At the same time a tripping point 153, Fig. 6, on the inner face of the element 38 lifts a lever 154 which in turn withdraws the latch 56 from beneath the bar 52. A shoulder 70, Fig. 5, on the bar 52 thereupon shifts the pin 45 to the leit, thus declutching the rapid-feed. The bar 53 is raised on the return motion and the latch 56 again engages therewith. At the completion of sewing, the cam-declivity 86, Fig. 7, on the disc 38, allows the stop-motion lever 72 to return to stopping position. The stopmotion tooth 75, Fig. 1, has fixed thereto a lateral pin 155 which engages with a slotted lever 156 pivoted at 157 to the bracket 74. A lever 159 pivoted to the lever 156 is yieldingly held against a fixed pin 162. When the tooth 75 rides up the cam-rise 78, a tooth 160 on the lever 159 snaps under a shoulder 164 of an arm 165 fixed to the shaft 157. When the tooth 75 drops into the stop-notch of the cam 77, the tooth 160 rocks the arm 165, and with it the lever 138 and the latch 60, to start the rapid-feed and return the work from sewing to cutting position. Clamps, closing, spreading, opening. The workholder is of the type described in Specifications 10039/14 and 183,873. The anti-cloclwvise movement of the arm 18, Fig. 1, actuates the lever 16 to close the work-clamp. A lever 131 pivoted at 132 to the frame is rocked by a cam 129 on the cutter-shaft after cutting has taken place, so that the end 134 of the lever pushes forward the lever 32 of the usual toggle-mechanism to spread the work-clamp. The extremity of a bar 166, Fig. 7, fixed to the work-holder is bent to form a camincline 167. One arm 170 of a bell-crank lever 169, 170 pivoted to the machine standard is connected to the usual clamp-opening push-rod 171 from which depends the unspreading arm 172. A lever 174 pivoted to the arm 169 is yieldingly held against a pin 176 thereon. Rearward motion of the work-holder from sewing to cutting position rocks the lever 169, 170 to push forward the rod 171, thus opening and unspreading the workclamp. Starting and stopping. A tappet arm 182, Fig. 3, fixed to a rock-shaft 181 engages an arm 183 of the lever 147. To the forward end of the shaft 181 is fixed an arm 184, Fig. 1, the end 185 of which underlies a cam-incline 186, Fig. 5, on a block 187 fixed to the starting-rod 117. When the rod 117 is pulled down to start the machine, the arm 184 and therefore the arm 182 will be rocked by the cam 186. The arm 182 swings the lever 183, 147, Fig. 3, thus releasing the link 123 in readiness to actuate the cutter-starting mechanism. When the rod 117 is fully depressed, the arm 184 snaps over the block 187 to latch the starting-rod. During the final movement of the rapid-feed shaft 36, a tripping point 188, Fig. 5, on the usual gear 37 swings outwardly an arm 189 pivoted to the frame. The arm 189 engages a tail 191 of the arm 184 and swings the latter outwardly to release the starting rod.