Patent GB-753149-A (GB)
Title: Method of and apparatus for assembling fastener elements
IPC: D05B3/18
Filed: 1954-02-23
Abstract: 753,149. Sewing-machines. RABINOWITZ, L. M. Feb. 23, 1954, No. 5280/54. Class 112. Fasteners are secured in spaced groups of two or more, as shown, eyelets grouped in pairs 15, 151, between the overlapped edges 11, 12, of a strip 10 by means of a line of stitching by apparatus comprising an element 25 adapted to draw the strip past a sewing head 100, a rotary control cam 50 formed with surfaces adapted to impart motion to a cam follower 55 and separated by dwell surfaces, means for connecting the follower 55 with the element 25 for imparting step-by-step movement to the latter, a second rotary cam 70 formed with lobes separated by dwell surfaces and adapted to impart movement at predetermined intervals to a follower 75, and means for converting movement of the latter into transverse movement of the sewing head; the arrangement being such that one of said cam lobes engages the follower 75 each time the sewing head is midway between fastener groups, at which time follower 55 is engaged with a dwell surface on cam 50, and follower 55 being moved immediately before and after follower 75 engages said lobe, whereby a lateral sticth 20 is formed midway between the groups to provide a mark for subsequent cutting of the strip, and at least one longitudinal stitch is formed on each side of the cutting mark. As shown in Fig. 6, a double transverse stitch 16 is made immediately ahead of eyelet 15, followed by a long stitch 17 across the leading limb 13 of the eyelet, a short stitch 18, a long stitch 21 across the trailing limb 14 of the eyelet, a double lateral stitch 22 at the immediate rear of the eyelet, six short stitches 23, similar stitches 16<1>, 17<1>, 18<1>, 21<1>, 221 made in conjunction with the second eyelet 15<1> of the pair, three long stitches 27, a transverse stitch 20 which forms the cutting mark, and three long stitches 28; the above cycle of stitches being repeated for each succeeding pair of eyelets. Strip 10 is gripped between a knurled, driven roller 25 fixed on a rotatable shaft 31 and an idler roller 32 carried by a pivoted, spring- biased, arm 33. Cam 50 is rotatably mounted on a shaft 43 and is driven by a train of gears 41, 42, 44, 46, 40, 45. Follower 55 is a roller carried by one end of an arm 52 slidably mounted on shafts 31, 43 by means of respective slots 53, 54. A tension spring 56 secured to the other end of arm 52 serves to bias the roller against the cam. Said other end carries a rack 58 engaging a pinion 60 rotatable on shaft 31; and a pawl 61, pivoted on pinion 60, is biased by a spring 62 into engagement with a ratchet wheel 37 fixed to shaft 31 and formed with alternate long and short teeth. Forward movement imparted to arm 52 by the roller serves to rotate shaft 31 by the engagement of the pawl and ratchet wheel; shaft 31 remaining stationary when the arm is moved rearwardly by spring 56. Cam 70 is a disc formed on its periphery 81 with spaced lobes 82a to 82h, is mounted on a shaft 74, and is driven by a worm 71 and worm-wheel 72. The follower 75 is a roller carried by one end of an arm 76 adjustably pivoted at 78, the other end of the arm being adapted to move the sewing head laterally in a slideway 101 when the roller is displaced by any one of the lobes. In the position of the apparatus shown in Figs. 2 and 5, roller 55 has just completed traversing a relatively shallow depression 91a in cam 50, when arm 52 moved rearwardly to allow pawl 61 to move over a short tooth of the ratchet wheel, and roller 75 rode over lobes 82c, 82d to form stitch 22. Roller 55 is next engaged by a succession of steps 92a, whereby stitches 23 are formed, roller 75 then being engaged by the concentric periphery 81. Roller 55 next engages a concentric portion 94 to stop the feeding of strip 10, when roller 75 rides over lobes 82e, 82f to form stitch 16<1>. Roller 55 is next engaged in succession by a high step 92b, low step 92c and high step 92d to form stitches 17<1>, 18<1> and 21<1>, while roller 75 rides on the periphery 81. Roller 55 next rides down a relatively deep depression 91b to allow pawl 61 to move over a long tooth of the ratchet wheel; roller 75 riding over lobes 82g, 82h to form the transverse stitch 22<1>. Roller 55 next engages in succession three high steps 92e to form the stitches 27, a concentric portion 96 when roller 75 passes over a lobe 83 to form the lateral cutting mask 20, three high steps 92f to form the stitches 28, a concentric portion 97 when roller 75 passes over lobes 82a, 82b to form the lateral stitch 16, and finally in succession a high step 92g, a low step 92h and a high step 92i to form the respective stitches 17, 18, 21. Cams 50 and 70 have then each completed one revolution and are in a position to repeat the cycle of stitches. The difference in the amount of rearward movement of arm 52 goverened by the respective depressions 91a, 91b and which corresponds to the respective length of the short and long teeth of the ratchet wheel, also corresponds to the difference in the distance between stitches 22 and 21<1>, as compared with the distance between stitch 21<1> and the succeeding stitch 22.