Patent GB-105683-A (GB)
IPC: D05B27/18
Abstract: 105,683. Fairweather, W., (Singer Manufacturing Co.). July 12, 1916. Overhead sewing-machines.-The shaft 76, Fig. 1, of the feed-wheel 79 is driven at different speeds bv a series of ratchet-wheels 84 - - 89 of different sizes and of the same pitch actuated by a lever having a constant amplitude of oscillations and carrying pawls each of which can, at the will of the operator, be brought into a position for engagement with its respective ratchet-wheel while the others remain out of action. The lever comprises a block 97, Fig. 5, having a series of pawls 102 mounted in recesses and adapted to be pressed outwards by springs 103 and retracted by rods 104. The lever is pivoted on a shaft 93 having an enlarged portion 95 with a series of recesses 96 each adapted to be brought into register with one of the rods 104 and allow the corresponding pawl to be pressed outwards by its spring, the other pawls being held inoperative by their respective rods riding over the unrecessed parts of the cylinder 95. The shaft 93 is turned to bring any desired pawl into action bv a head 110 which is correspondingly marked and has a series of correspondingly arranged recesses 111 entered by a spring detent 112 by which it is locked in position. The lever is oscillated by an eccentric rod 124 connected to the arm 118 of a two-armed lever pivoted at 120. A link 115 is connected to the end 117 of the arm 118 and at 101 to an arm of the pawl-carrying lever 97, the point of connexion between the rod 124 and arm 118 being so disposed that in one extreme position the connexion 117 is in line with the points 101 and 120, in order to give a dwell at the end of each feeding movement. The presserwheel 162 is adjustably mounted in an arm 167 which swings about a shaft 169 and has an arm 180 carrying a post 181 with adjustable spring 185 bearing on the end of a. lever 183 which is pivoted on the arm 180 by the projection 184 and notch 182 and bears against an adjustable stop consisting of a cam 190 on a shaft 189 carrying the handlever 195 by which adjustments of the pressure of the wheel 162 are made. A lever 199 connected to a treadle or the like and supported on the shaft 189 has a roller 198 bearing under the arm 180 for separating the two wheels against the spring 185. The needle-bar is reciprocated by a pin secured thereto and having a sliding bearing in tangential sleeve on the strap of an eccentric on the main shaft. The looper-bar is reciprocated and vibrated in a vertical plane by having a universal connexion with a rocking and reciprocating member pivoted on the end of a swinging arm 12 and having arms 15, 16 with rollers engaging differently shaped cam-grooves in a gear-wheel 5 secured to the main-shaft and a wheel 8 driven thereby and mounted on a shaft 4. Horizontal vibrating movements are communicated to the looper-bar by a swinging lever supported on the shaft 4 and actuated by a cam-groove 7 on the wheel 5. The lever has an offset projection 55 connected by a pitman 58 and ball-joints with one arm of a bellcrank lever in the other arm 42 of which is pivotally mounted a block 39 having lugs between which is pivoted a sleeve 37 supporting the looperbar. The needle-thread is passed from the supply through a tension 160 and a take-up comprising a post 157 with a longitudinal slot and a spring- pressed thimble to a guide 128, Fig. 9, on the needle calmp-block 62, and is clamped when the needle completes its thrust through the material by a plate 129 on the end of a slide-pin 130 mounted in the clamp block and actuated by a pin 131 on one arm of an angle-lever pivoted at 138 and controlled by a spring 136. The other arm 133 of the lever carries a roller 134 which is engaged by the pin 140, Fig. 1, secured within the forward arm 141 of a rock--lever journaled on a rock-shaft 143 and having an oppositely extending arm 144 which is resiliently connected by the pin 145 and spring 149 with the arm 146 of a collar secured on the shaft 143. This shaft is rocked by the arm 151 which is connected by the pitman 154 to the arm 121 of the rock-lever pivoted on the shaft 120 through which the feed-wheel is actuated.