Patent GB-350940-A (GB)
Title: Improvements in or relating to the co-ordination of lasts and shoe upper patterns
IPC: A43D3/02
Filed: 1930-03-17
Abstract: 350,940. Pantographic apparatus. FITZ EMPIRE DOUBLE PIVOT LAST CO., Minot Avenue, Auburn, Maine, U.S.A.- (Assignees of Burke, E. H. ; Lynn, Massachusetts, U.S.A.) March 17, 1930, No. 8498. Convention date, May 29,1929. [Class 97 (iii).] Comprises the production from a model, of a number of shoe upper patterns of different sizes and of such shapes as to fit the corresponding lasts in a set which have been generated from a last model in such a manner that they have uniform toe spring and heel height. In the production of lasts from a model by the use of pantographic apparatus, all the lasts are geometrically similar to the model so that the above-mentioned characteristics are different for the different sizes. To secure the desired uniformity, the finished lasts may be distorted by hand, or, by the use of a suitable last lathe, the desired distortion can be obtained during the production of the last. The operation of such a lathe is, in effect, to divide the model last into a number of laminae perpendicular to its longitudinal axis, and to produce the effect of relative displacements of successive laminae at right angles to the said axis during the pantographic reproduction, so that parts of the last are raised or lowered relatively to the corresponding parts of the model. According to the invention the upper patterns are produced from a model which would itself correctly fit the above-mentioned last model, in a pattern-grading machine of such construction as to enable a set of patterns to be produced, each shaped to fit correctly a corresponding member of the set of lasts produced as above described. The Figures show a grading machine by the use of which the desired set of patterns can be produced, the machine comprising a pattern-holding plate 12 slidably mounted on guides 14 on a frame 10 on which is also mounted a carriage 20 which can slide on guides 22. The carriage 28 carrying the tracer 30, and a carriage 32 are arranged to roll on the carriage 20 on guides 24, 26 at right-angles to the guides 22. The length-grading lever 38 is pivoted to a slide 36 mounted on a guide 34 on the carriage 20 and to the carriage 28 at 40. The lever 38 is also pivoted to a link 42, one end of which is adjustable in a slot 44 in the lever, while the other end is pivoted at 46 to the carriage 32. A carriage 48 carrying the cutter 50 is slidably mounted on guides 52 on the carriage 32. The width grading lever 58 is pivoted at 56 to the carriage 32 and has adjustably pivoted thereto one end of a link 60 to the other end of which is pivoted to the carriage 48 at 62. The pivot 64 of the lever 58 is mounted in a carriage 66 sliding on a rib 68. A hanger 70 suspended from the carriage 32 engages a rod 72 in such a way as to impart thereto only those movements of the carriage 32 in the direction of the length of the rod. The rod 72 is formed at its end as a rack 76 engaging a pinion 78 which drives a pinion 82 through gearing 84, 86 and spindle 88. The pinion 82 drives pinions 90, 92 in opposite directions. The pinion 90 is mounted on a spindle 96, Fig. 8, on which is freely mounted a pinion 98 separated from the pinion 90 by friction discs 100. The upper end of the spindle 96 receives a nut 102 through which pass screws 104 engaging a groove on the boss of the pinion 98 so that when the nut is screwed down the pinion 98 is driven frictionally by the pinion 90. The pinion 92 is similarly arranged so that it can drive a pinion 108. The pinions 98, 108 both engage a wheel 110 which is thus driven in one direction or the other according as one or other of the nuts 102, 106 is screwed down. The wheel 110 carries a segment 112 in which is adjustably mounted one end of a link 114 the other end of which is connected by.a lever 118 to a link 124 pivoted to the plate 12 carrying the pattern 126. By this means the plate can be displaced over the guides 14 through a distance depending on the distance of the tracer from its point of origin on the model, and this displacement produces the required distortion of the pattern to make it fit the last. By slackening both of the nuts 102, 106 the displacement of the plate 12 can be discontinued when desired to enable ordinary pantographic reproduction to be proceeded with. The distortion of the graded pattern is confined to the part lying between the heel and toe portions, the said portions themselves being graded pantographically from the model.