GB458912A - Thread-cutter for sewing machines - Google Patents

Abstract

458,912. Sewing-machines. SINGER MANUFACTURING CO., Elizabeth, New Jersey, U.S.A. July 16, 1936, No. 19715. Convention date, Oct. 4, 1935. [Class 112] The thread cutter of the buttonhole-sewing machine described in Specification 223,124, [Class 112], is improved by making the upper blade of the scissors of a broad spatulate shape so that it safely grazes the work, however rough the surface, and catches the thread without snagging. In the form shown, the stitch-forming mechanism is the same as that described in Specification 179,278, [Class 112]. The stop-motion device, feed wheel mechanism and work-clamp mechanism are as described in Specification 183,873, [Class 112]. The cutting-device comprises the usual cutter-carrying lever 36, Fig. 2 pivoted on the stud 37 and connected by the link 38 to the arm 39 of a lever with another arm having a roller following the cutteractuating slot of the gear on the rapid feed shaft in the manner described in Specifications 223,801, 224,845, and 226,134, [all in Class 112]. The lever 36 carries the supporting shank 44 of the thread-cutter, the blades 46, 47 of the scissors being pivoted thereon at 45. The upper blade 46, Fig. 9, has a tail portion 48 with a screw 49 adjustable in a slot 50 in the shank 44 to determine the radius of action of the thread-catching end of the blade. The lower blade 47 has the usual lateral stud which enters the groove 52 of the stationary scissors closing and opening cam 53. The nose of the upper or ledger blade 46 is formed with a bill-shaped or spatulate end 54, Fig. 10. This end is formed for convenience on a separate member 55 overlying the blade and secured by the screw 49. This end slides smoothly under work of the roughest texture without snagging and catches the threads. A spring 57 holds the lower blade 47 in working contact with the upper fixed blade 46. The lower clamp plates 27 are provided with clearance apertures for the thread cutter to allow the spatulate end 54 to graze the under surface of the work. These apertures are covered by a pair of thin plates 61. The thread gripper 67 seizes and removes the severed or waste loop of the needle thread after the manner described in Specification 223,124. Specifications 290,476, and 322,951, [both in Class 112], and 352,214 also are referred to.