| 摘要 |
950,397. Sewing machines. SINGER CO. Oct. 9,1962 [Oct. 9,1961], No. 38188/62. Heading D1G. [Also in Division F2] An eccentric 25, driving a work feed-advance pitman 28, has a tongue 24 slidable in a transverse groove 23 formed in a flange 22 fixed to the bed shaft 19 of the sewing machine. The eccentric is formed with a cylindrical bore 27 which is inclined to the axis of shaft 19 and which is slidably engaged by the inclined cylindrical end 37 of a sleeve 36 longitudinally slidable on shaft 19. An axial bore 30 in the latter slidably supports a rod 31 fitted with a transverse pin 32 which extends through longitudinal slots 33 in shaft 19 and through clearance holes in sleeve 36. Pin 32 also extends through longitudinal slots in a sleeve 39 which is fixed to shaft 19 and within which sleeve 36 is slidable with rod 31 for varying the eccentricity of eccentric 25. Sleeve 39 is formed with external lefthand screw threads 41 and righthand screw threads 42 engaged with respective stop nuts 50 and 43 disposed one on each side of pin 32. A pin 48 fixed to nut 43 passes through a clearance hole 49 in nut 50. Pin 32 normally abuts nut 43,under the bias of a spring 34 in bore 30, to establish a rate of forward feed. Actuation of a lever 60 moves pin 31 inwardly, via a linkage 62 to 65,till pin 32 abuts nut 50 to establish the same rate of reverse feed. Nut 43 is formed with a peripheral groove 45 engageable by a plunger 46 when the latter is depressed against the bias of a spring 47, to hold the nuts 43, 50 from rotation. Turning of the handwheel 15 in one direction thereby moves the nuts apart to increase the rate of feed, and in the other direction moves the nuts towards one another to reduce the rate of feed, the position of zero feed occurring when both'nuts abut the pin 32. Specification 786,712 is referred to. |
