GB691663A - Sewing machine lubrication - Google Patents

Abstract

691,663. Sewing-machine lubrication. FAIRWEATHER, W. C. (Singer Manufacturing Co.). Dec. 17, 1951,No. 29428/51. Class 12 (iii). A sewing-machine comprises a hollow frame provided with a shaft-bearing and an oilcollecting recess at the outward side of the bearing, means within the frame for supplying lubricant to the bearing, an oil-return conduit leading from the recess and terminating within the frame, and a vapour-lock associated with the conduit to prevent lubricant-laden air within the frame from passing through the conduit. As shown, a shaft 6 is journalled in bearings including a bushing 5 in the upper arm of a chainstitch sewing-machine. The shaft carries a hand-wheel 8 and a gear 12 meshing with a gear 13 secured to a vertical shaft 14, which at its lower end is operatively connected to an oil pump 22. The pump supplies oil through a pipe 24 to a longitudinal bore 29 in the shaft 6. The oil passes through a radial bore 30 to the gearwheels 12, 13 and through a radial bore 31 to a helical groove 32 on the shaft and to a recess 34 in the bushing 5. An oil-sling 33 formed upon the hand-wheel 8 projects into the recess and flings the oil against the walls of the recess. The oil runs down an inclined conduit 35 which has an opening 37 in which is fitted a tube 41. The tube is carried by a sheet-metal strap 38 secured to the outer periphery of the bushing 5 by a screw 39 passing through an aperture 40 in the strap. The lower portion of the tube extends into a wall 42 which is always full of oil, providing a liquid seal which prevents oil-laden air from passing up through the conduit 35. In a modification the tube 41 and strap 38 are replaced by a smaller tube and a spring strap of arcuate shape larger than a semi-circle so that it is self-clamping on the bushing. The tube contains a wire-mesh screen, the holes in which are normally closed by droplets of oil, thereby forming the liquid seal preventing escape of oilladen air through the conduit 35.