GB547678A - Improvements in or relating to sewing machines - Google Patents

Abstract

547,678. Sewing-machines. JACKSON, L. MELLERSH-. (International Button Hole Sewing Machine Co.). March 4, 1941, No. 2941. [Class 112] A needle-bar 35 slides in a sleeve 34 mounted on cross pivots 36, 37 and is laterally vibrated in two directions at right-angles from cam-grooves 54, 55. For stitching a tacking group the groove 55 is a spiral joined up by a step portion and a spring 87 assists the bowl through the step portion. For attaching buttons, the groove is two semi-circular portions joined up by two step portions. The motion is communicated by means of a bar 63 sliding in a pivoted block 61. The groove 55 gives the bar a longitudinal motion by means of a lever 78 and a link 83. The groove 54 gives it an oscillatory motion through a lever 74, 71 and a link 68 and the amplitude may be varied by shifting the connection of the link 68 with the arm 71. For button-attaching, a slotted quadrant lever and adjustable radius rod may be inserted for varying the longitudinal movement. The shuttle and its shaft 110 are given an axial movement corresponding to the longitudinal movement of the bar 63 by means of a lever 115, fast on the shaft 77 carrying the lever 78, engaging between a pair of collars 112 on the shuttle shaft 110. The cyclical position of the shuttle beak is advanced and retarded to suit the transverse vibration of the needle by the relative displacement of helical toothed wheels 121, 122 by which the shuttle shaft is driven from a shaft 124. The wheel 121 is held from axial movement with the shuttle shaft 110 and the wheel 122 is carried by a sleeve 135 which is moved axially upon the shaft 124 by a third cam groove 56 acting through an arm 149, a quadrant lever 146, a link 143 and a lever 138. The shuttle is supported and driven by six levers 99 carried by the shaft and caused to move into and out of recesses in the shuttle body by a cam surface enclosing the levers and formed within a non-rotating block 96. The block 96 and a throat plate 195 attached to it move axially with the shuttle shaft 110. The bobbin case is held from rotation by the alternate engagement of arms 178 with a groove 177 in the bobbin-case front. These arms are carried on a shaft 170 which is oscillated by means of a lever 179 and a crankpin 191, which may be adjustable, on a disc 183 gear-driven from the shaft 124. The shuttle may be replaced by a rotary chain-stitch looper, Fig. 15, which is driven by the levers 99. In place of the bobbin-case retainer a needle-thread loop spreader is mounted on the shaft 170. The shuttle makes two revolutions for each stitch and the chain-stitch looper one revolution for each stitch. Accordingly, change wheels are provided for the shaft 124 and the large wheel connecting the wheels on the shafts 42, 124 is suitably mounte for the necessary adjustment.