Patent GB-843533-A (GB)
Title: Improvements relating to zig-zag sewing machines
IPC: D05B3/24
Filed: 1956-06-21
Abstract: 843,533. Sewing machines. ANKER-PHOENIXNAHMASCHINEN A. G., [formerly PHOENIXNAHMASCHINEN AKTIENGESELLSCHAFT BAER & REMPEL]. June 21, 1956 [June 25, 1955], No. 19279/56. Class 112 Button-hole machines; needles shifting laterally. In stitching a button-hole, Fig. 17, the locking stitches at the ends of the hole are made under automatic control and the stitching at the sides of the hole is performed under manual control. The controls include a cam shaft 5, Fig. 1, carrying a cam 7, and a loose bush 10 to which cams 8, 9 are secured and which is provided with teeth for engaging recesses in a flange 13 on the shaft. The bush carries a permanent magnet 50. The cam 7 effects continuous oscillation of a follower 14, Fig. 6, pivoted at 15 and pivotally carrying at 39 a follower 38 adapted to engage the cam 9 and to be engaged by the pointed end 41a of a bar 41 connected to the upper end of the needle bar frame 42 which is pivoted at 43. The cam 8 is contacted by one arm of a bell-crank lever 16, the other arm of which is slotted to receive adjustably a pin 19 connected by a steel band passing over a guide roller 22 to an arm 23, Fig. 2, on the feed control shaft 24. With the machine at rest the cams 8 and 9 are held out of action by cam surfaces on the underside of the cam 9 engaging cam surfaces on a clutch ring 55 so as to hold the bush 10 out of engagement with the flange 13. Actuation of lever 60 to turn the clutch ring produces disengagement of these cam surfaces and allows the bush to move into engagement with the driving flange 13 so that when sewing is commenced locking stitches are produced under automatic control with the work moving rearwardly. After a half revolution of the cam shaft the co-operating cam surfaces on cam 9 and the clutch ring cause disengagement of the bush 10 from flange 13 and the right hand border sewing is effected until the lever 60 is again actuated manually to repeat the sewing cycle but with forward movement of the work. The cam 9 amplifies the movement produced by the cam 7 during production of the locking stitches and also effects a bias to one or other side of the button hole during production of the border stitches. The point of contact of the bar 41 and the follower 38 may be controlled manually by a lever 44, and the lateral positions of the needle may be manually controlled by a lever 47 carrying a cam 48 adapted to engage a pin 46 on the follower 38. The guide roller 22 is carried on a pin 29 supported by a cam 28 on a hand lever 26 coupled by a pull rod to the arm 23 on the feed control shaft. In the position 34 of the hand lever the feed is controlled by the cam 8. In positions 35, 36, 37 the guide roller has been lowered to cut out automatic control and to produce maximum forward feed, zero feed, and maximum rearward feed respectively. The cams 7, 8, 9 may be designed as grooved cams and the number of teeth on the bush 10 corresponds to the number of crests on the cam 7. In a modification, a cam arranged on the bush 10 effects the amplification necessary to produce the locking stitches by moving the bar 41 along the follower 38. In a further modification a step mechanism or switch gear driven from the cam shaft actuates the clutch ring automatically to couple the cams 8, 9 to the cam shaft after a predetermined number of border stitches.