GB775069A - Improvements in sewing machine lubrication systems - Google Patents

Abstract

775,069. Sewing-machines. UNION SPECIAL MACHINE CO. Dec. 5, 1955 [Dec. 9, 1954], No. 34701/55. Class 112. [Also in Group XXXIV] In a sewing machine having a moving part which requires to be fed with lubricant at a precise rate, liquid lubricant is fed to this part through a capillary delivery element, and means is provided for adjusting the effective length of the capillary delivery element to adjust the rate of feed of lubricant. The machine shown is of the general character described in Specification 676,955 and has a rotary hook 21 which co-operates with a needle in the formation of lockstitches. The hook is secured to the end of a shaft 22 the bore of which is adapted to receive lubricant from a reservoir 37 by the aid of porous elements. A porous wick element 38 extends through an opening 39 in the reservoir and is folded over the end of a spring member 40 which presses the folded portion against the periphery of a circular portion 45 of a porous member. The circular portion is not a complete circle and one end has an inwardly-extending portion 46 carrying a smaller portion 47 adapted to fit tightly on the end of the hook shaft 22. The porous member is secured to a metal support 48 within which a disc 52 is firmly secured. The disc is pressed up against the end of the hook shaft 22 by a spring-pressed plunger 54 slidable within an axial opening in an adjustable shaft 56. The shaft 56 has a radiallyextending flange 58 with a pin adapted to cooperate with a notch in the disc 52. The shaft 56 has a helically-toothed portion 61 engaging a worm 62 on a bolt 63 journalled in the reservoir. The bolt has a slot 64 to receive a screw driver for turning the bolt and thereby turning the shaft 56. Thus the point of contact of the wick element 38 with the portion 45 of the porous member can be adjusted and thereby the rate of travel of the lubricant along the porous member can be varied. The lubricant delivered to the central portion 47 of the porous member is picked up by the co-operating face of the disc 52 and is then pumped to the bore of the hook shaft 22 by a spiral groove formed in the end face of the shaft. The lubricant passes along the bore of the shaft 22 to the raceway of the hook 21. The bore is preferably flared its diameter increasing towards the hook end, and it preferably contains a wick element 74 bent upon itself, so that a small amount of lubricant is retained within the bore when the machine is at rest.