GB1425184A - Sewing machine - Google Patents

Abstract

1425184 Sewing machines G TOLLE 23 Feb 1973 [6 May 1972] 8912/73 Heading D1G In a sewing machine having the needle 16 below the work and the loop taker 21 above it on a bracket arm which can pivot upwards, a work clamp 30 comprises upper and lower jaws, both supported on a base plate 40 which can also pivot upwards about a pin 41. The upper jaw 73 pivots about a pin 72 carried by the lower jaw, and carries a work engaging shoe 75 which presses the work against a tray 62 on the lower jaw. To move the work clamp while sewing a buttonhole for example, a belt 94 drives a sprocket clamped to an internally threaded sleeve 92, and so moves a threaded stud shaft 91 inside it. The stud Shaft is attached via an angle bracket 90 and a resilient mounting to a block 83 which slides in a groove 84 in the base plate and is attached to a sliding plate 80. As the sliding plate moves along the base plate the lower jaw is forced to slide at an angle to it because it carries blocks which slide in diagonal slots in the base plate. If the base plate is raised the tongue 100 which pivots on a pin 101 and is accommodated in a block 103 allows the sliding plate to be raised also. The base plate normally presses down against a spring biassed stud 130. To provide a constant distance between the loop taker and work of varying thickness the bracket arm carries a sliding rod 113 to which is attached a wheel 110 which presses against a track 77 on the work clamp. When the bracket arm is lowered the rod carrying the wheel is pressed upwards until a pin 116 which it carries reaches the end of a slot 115.