Patent GB-871968-A (GB)
Title: Improvements in or relating to sewing machines
IPC: D05B19/00
Filed: 1958-06-26
Abstract: 871,968. Sewing machines. GRITZNERKAYSER A. G. June 26, 1958 [June 26, 1957], No. 20491/58. Class 112 In a zig-zag sewing machine a handle or knob is adapted for simultaneous displacement both of a cam follower for selective engagement with any one of the cams of a rotary pattern cam pack, and also of a pointer, carried on an endless band, for indicating the corresponding pattern from a series of symbols disposed longitudinally of the machine arm, and a second handle, adapted to influence the work feed, is arranged coaxially with the first said handle. A pack of cams 1 is connected by a key 1a to a sleeve 54 journalled on a pin 55, removal of which enables one cam pack to be interchanged for another. The cam pack is connected by a pin 59 to a gear 5 driven by gears 4, 3, 2 from the arm shaft 6. A cam follower 8 is carried by a bush 62 slidable but non-rotatable on a spindle 83 mounted in a frame 60 pivoted on a fixed spindle 19. Oscillation of frame 60, consequent upon rotation of the cams 1, is transmitted to the needle bar gate 15, pivoted at 52, by a link 11, levers 12, 13 and a link 14. A screw-threaded spindle 10 carries a nut 64, and a finger 63 rigid with the latter engages a slot 61 in bush 62, whereby rotation of spindle 10 moves bush 62 along spindle 83. A gear 28 on spindle 10 meshes with a gear 27 on a rotatable bush 67. A sleeve 69, journalled in bush 67, has a manuallyrotatable knob 26 fixed to one end, and a sleeve 29, formed with a tapered end portion 66, fixed to the other end. An arm 31, pivoted on a fixed pin 32, normally engages the outer end of the tapered portion 66. If knob 26 is pushed inwards, portion 66 reacts with arm 31 to swing the latter. An arm 33 rigid with arm 31 then engages a spindle 34 rigid with frame 60 to swing the latter and thereby raise follower 8 from the cams 1. Knob 26 is simultaneously coupled to bush 67 by inter-engaging means 70, 71, whereby rotation of knob 26 will move follower 8 axially of the cams 1, and a gear 28 on spindle 10 will drive a sprocket 37, journalled on a pin 72, via a gear 40. A belt 36, connecting sprocket 37 to a sprocket 38, carries a pointer 35 which travels along a window 73 over a series of stitch diagrams 24 and 25, coloured green and red respectively, and corresponding to the respective cams lying under the follower 8. An end cam 17, rigid with the cams 1, is engageable by a follower 9 pivoted on a pin 16 and connected by an arm 75 to the work feed-control lever 22. Pin 16 is carried by arc arm 18 of a two-armed lever fulcrumed on spindle 19, the other arm 77 being biased against one or the other flat portions 79 or 80 of a disc 20, carried by a spindle 78 journalled in the sleeve 29 and 69. A knob 21 on spindle 78 enables one or the other flats to engage arm 77 for varying the position of pin 16 to engage or disengage follower 9 from cam 17. A green spot 81 on knob 21 is turned to the uppermost position to indicate engagement of follower 9 for producing the green stitch patterns 24. A red spot 81 on knob 21 is turned uppermost for producing the red patterns 25 with follower 9 disengaged.