Patent GB-888928-A (GB)
Title: Improvements in or relating to selector mechanisms for sewing machines
IPC: D05B19/00
Filed: 1958-08-08
Abstract: 888,928. Sewing machines. GRITZNERKAYSER A.G. Aug. 8, 1958 [Aug. 10, 1957], No. 25450/58. Class 112 [Also in Group XXIV] A zig-zag sewing machine comprises a pack of co-axial pattern cam discs, a carrier moveable parallel to the axis of the cams, and two or more followers pivotally mounted on the carrier to move into and out of operative position relatively to the cams, the followers being so spaced that each can co-operate with a proportionate number of the cams on displacement of the carrier, and the arrangement being such that when a follower is moved into operative position relative to a selected cam and thereby to engage the latter, no other cam is engaged by a follower. The swinging gate 2 for the needle bar 1 is connected by a linkage 4, 6, 7 to a frame 8 pivoted on a shaft 9. A carrier sleeve 10, slidable on shaft 9 and coupled to frame 8, has pivotally mounted thereon a pair of cam followers 11, 12 which are biased by respective springs 18 away from a pack of pattern cam discs 17 fixed to a rotary driving shaft 16. Cam discs 17 are eleven in number and are interleaved with separator discs 17a, the pack thereby comprising twenty one discs of equal thickness. The followers 11, 12 are spaced from each other at a distance equal to half the sum total of the width of the discs. The ends of the followers remove from the discs are formed with respective abutment edges 21, 22 each one half the width of a disc, and said edges are biased by the springs 18 into engagement with a backing bar 19 which is carried by frame 8 and is formed along the side facing the discs with a series of alternating teeth 20 and notches 20a, the width of each tooth and notch being half the width of a disc. When follower 11 is opposite the first disc, namely a cam disc 17, it is held in engagement therewith for oscillating the needle bar by the engagement of edge 21 with a tooth 20, and follower 12, which is situated between the eleventh and twelfth discs, is raised by a spring 18, since the edge 22 lies in a notch 20a. At each successive displacement of sleeve 10 by an amount equal to half the width of a disc, the edges 21, 22 will engage teeth and notches in alternation. At the third such displacement, e.g., follower 11 will be in the raised position between the second and third discs, and follower 12 will engage the thirteenth and cam disc 17, while at the fourth such displacement follower 11 will engage the third, and cam disc, and follower 12 will be in the raised position between the thirteenth and fourteenth discs. Sleeve 10 is coupled by an arm 15 to a nut 13 mounted on a rotary, screw-threaded shaft 14. A gear 23 on the latter meshes with a gear 24 on a hub 26 journalled in a bearing 27. A sleeve 28, journalled in hub 26, carries at its outer end a handle 25 and at its inner end a sleeve 33 which terminates in a conical cam face 34. When handle 25 is pushed inwardly, means 31 thereon engage means 32 on hub 26 to couple the latter with the handle. Cam face 34 simultaneously engages an arm 35 of a twoarmed lever to turn the latter anti-clockwise, when the other arm 38 engages a stud 39 on frame 8 to turn the latter clockwise against the bias of a spring 41. During this movement of frame 8 the edges 21, 22 engage a fixed abutment bar 40 and are thereby withdrawn from engagement with bar 19. Turning of handle 25 will then serve to displace sleeve 10 for selecting the required cam disc 17. A visual indicator may be associated with the handle. Specification 871,968 is referred to.