Patent GB-948572-A (GB)
Title: Embroidery appliance for sewing machines
IPC: D05B27/24
Filed: 1962-10-22
Abstract: 948,572. Cams. MEFINA S.A. Oct. 22, 1962 [Oct. 26, 1961], No. 39836/62. Heading F2K. [Also in Division D1] A sewing machine attachment comprises a work - supporting frame adapted to be moved in two mutually perpendicular directions by means of two mechanisms each controlled by a follower co-operating with a respective cam profile, each mechanism comprising means which can either be made operative to enable the followers in contact with the cam profiles to position the frame in accordance with the latter, or can be made inoperative to allow withdrawal of the cam followers from the profiles, the frame being locked in position while said means is inoperative. The attachment is in the form of a housing 58, Fig. 11, supported on the free arm 6 of a sewing machine. A work-holding frame 1, Figs. 1 and 5, has bearing lugs 3, 4 slidable transversely of arm 6, against the bias of a spring 11, on a rod 5 carried by a frame 7. A bar 8, carried by the latter, is slidable longitudinally of arm 6, against the bias of a spring 12, in bearing lugs 9 on housing 58. A pattern bar 13, slidable in a guideway 57 in housing 58, carries a stepped profile 14 which co-operates with a follower 16 for imparting transverse movements to frame 1, and also carries a stepped profile 15 co-operating with a follower 17 for imparting longitudinal movements to frame 1. The followers are rigid with respective slidable blocks 18, each of which is connected by a pair of toggle links 21, 23 to a respective slidable block 25. Block 25 connected to follower 16 carries a pin 30 engaged with one arm of a bell-crank lever 32, the other arm of which abuts lug 3. Block 25 connected to follower 17 abuts frame 7. A member 26 is formed with a slot 27 engaged by a fixed pin 28, and is also formed with a slot 29 engaged by the pivot pins 22 interconnecting the respective toggle links 21, 23. Member 26 is pivoted to a lever 46 pivoted at 47 to housing 58 and formed with a recess 45 embracing a triangular cam 44 on a rotary shaft 43 journalled in housing 58. A lever 38, pivoted at 39 to housing 58, has one arm biased by a spring 40 against a cam 42 on shaft 43. The other arm of lever 38 is adapted to engage or release a slidable brake block 36 acting on the blocks 25. A lever 51, pivoted at 52 to housing 58, has one arm biased by a spring 56 against a cam 49 on shaft 43. The other arm of lever 51 carries a pawl 54 adapted to co-operate with a rack 55 on pattern bar 13. Shaft 43 is adapted to be coupled to a corresponding driving shaft in arm 6. Initially, brake 36 is applied to the bars 25, and the toggles are broken to withdraw the followers 16, 17 from the profiles 14, 15. On rotation of shaft 43, pawl 54 shifts the pattern bar 13 the width of a cam profile step, brake 36 is released, and member 26 is shifted to straighten the toggles for engaging the followers with the cam profiles for re-positioning the frame 1. Brake 36 is then re-applied for fixing frame 1 in its new position and a stitch is inserted. In a modification, Fig. 8, equivalent parts bear the same reference numbers. Each follower 16, 17 is carried by a slidable bar 71 telescopically engaging a rod 75 rigid with a slidable bar 73. One of the latter abuts the lever 32 and the other abuts the frame 7. Compression springs 77 are interposed between the respective bars 71 and 73. Lugs 78, depending from bars 71, engage a member 79 which is connected to housing 58 by two parallel pivoted bars 80 and which is engaged by a lever 88 pivoted at 89 to housing 58 and co-operating with cam 44. Cam follower lever 38 is pivoted at 82 to a bar 83 which is slidable transversely of the bars 73. A lateral extension 86 of bar 83 is adapted to displace a brake block 36b engaging one bar 73, and an adjustable stud 87 carried by lever 38, is adapted to displace a brake block 36a engaging the other bar 73. On rotation of shaft 43, pawl 54 feeds the pattern bar 13, lever 38 swings to release the brake blocks, and lever 88 swings to allow the springs 77 to bias the followers 16, 77 into engagement with the cam profiles and the bars, 73 to shift the frame 7 and lever 32 accordingly.