GB579253A - Improvements in or relating to sewing machines - Google Patents

Abstract

579,253. Sewing-machines. NEWTON, E. P. (International Button Hole Sewing Machine Co.). Sept. 8, 1943, No. 14736. [Class 112] A machine for sewing four, or two, hole buttons or the like on to material, such as described in Specifications 476,039 and 476,080, is provided with cam-operated means to move a needle bar 21 into position x, Fig. 1, to form the stitches s<1>, Fig. 2, and then into position y to form the stitches s<2>, the work remaining stationary. A single cam 40 has two grooves 78, 79, Fig. 5 which are alternately engaged by pins 73, 74, connected as shown in Fig. 9, a ramp 82 depressing one pin 73 and automatically raising the other pin 74. The needle-bar 21 is reciprocated in bearings 23, 230 by mechanism 9 actuated by a shaft 89. For a four-hole button a carrier 25 is oscillated laterally during successive descents of the needle 20 to cause the needle to pass alternately through the holes a and b, Fig. 2, after which the carrier is shifted longitudinally to bring the needle into the plane of the other holes c, d. The carrier slides in a groove bearing 26, and is oscillated laterally about the axis of a pivot 27 by a link 30 having a pin 31 projecting into a slot 32 in the upper face of 25. A stud 33, at the other end of link 30, operates in a slot 34 in a lever 35 which is oscillated about a pivot 36<1> when one or other of pins 36, 37, is engaged in one of the cam grooves 38, 39. Manually-operated means are provided to select either pin 36 or 37, according to the number of stitches required, since the groove 38 has more indentations than the groove 39 and thus produces more stitches per revolution of the cam. The cam 40 is also provided with grooves 42, 43, which, through linkage (not shown) control the operation of loopers 22. The degree of longitudinal movement of 25 is determined by the position of a link 52 pivoted to 25 by a pin 53 at one end, and to a block 57 in a grooved lever 59, at the other end. The lever 59 oscillates about a shaft 60, but when the block 57 is moved along the groove 58, by manual means, to coincide with the shaft 60, there will be no longitudinal movement of 25, as when a two-hole button is being stitched. The pins 73, 74, are carried by an arm 71 keyed to the shaft 60, and alternately engage the grooves 78, 79, as described above. Notches a<1>, d', cause movements of the arm 71 which turns the shaft 60 and moves the lever 59. A pin 90 engages one or other of two grooves in the arm 71 to prevent lateral movement of the arm when the pins 73, 74, are being changed over by contact with one of the ramps 82.