GB817112A - An adjustable cam or cam assembly, particularly for use in automatic zig-zag sewing machines - Google Patents

Abstract

817,112. Sewing machines. MESSERSCHMITT A. G. Dec. 14, 1956 [Jan. 14, 1956], No. 38204/56. Class 112 [Also in Group XXIV] An adjustable cam for stitch control mechanism of a zig-zag sewing machine such as described in Specification 803,394 comprises a disc 13, Fig. 2, mounted on a shaft 4 and provided with a number of radial slots 14 to receive cam elements 15. These cam elements are urged inwards by springs 32 or 35 and moved outwards by tappets 24 which are engaged by a keylike setting member 21 inserted in a bore of the shaft 4. In Fig. 1 a set of four such cams is shewn at 8 for controlling the stroke of the feed dog and another set of four cams at 9 for controlling the width or position of the stitch. These sets of cams are controlled by key-like setting members 22 and 21 respectively which may be changed to produce different patterns. One non-adjustable cam 10 is also shown for controlling the zig-zag stitch mechanism. The key-like setting members may be retained by click catches 69, 70 and may be shaped so as to slip easily into the shaft bore and not actuate the tappets 23 until a final rotation is given which also locks it in position. Alternatively, the keylike setting member may be inserted and resiliently held in a non-operative position until a final axial movement is given. In another arrangement the key-like setting member must first be inserted to an inoperative position in a sleeve member with radial plungers which is then inserted in the shaft bore. The key is then moved further axially into the sleeve to move the said plungers radially to actuate the tappets of the cam elements.