GB584382A - Lubricating device for sewing machine loop-takers - Google Patents

Abstract

584,382. Sewing-machines. SINGER MANUFACTURING CO. May 20, 1944, No. 9797. Convention date, Dec. 21, 1943. [Class 112] [Also in Group XXXIV] Lubricating.-In a rotary-hook lock-stitch sewing-machine in which the axis of the hook is'vertical lubricant is fed to the hook raceway through a bore in the hook shaft which is inclined away from the axis of the shaft so as to produce a centrifugal force to lift the lubricant along it, and the lower end of this bore is fed by a conduit or auxiliary reservoir having its intake opening above the level of the lubricant in a main reservoir, oil being lifted to the intake opening by means acting when the machine is in operation. In the arrangement shown, the hook shaft 25 is driven by helical gears from a horizontal shaft 19, the gearing being enclosed in a housing 29 which acts as an oil reservoir, having at one corner a chamber into which a filler-plug 78 (acting also as a dip-gauge) enters. Part of the floor of this chamber is raised to form a ledge 52 a little above the level of the oil, and the lower end of the hook shaft 25 bears in a bushing 30 in this part of the chamber floor, the lower end of the bore of the bushing being closed by a plug 65 having a spigot portion extending into a bore in the end of the shaft 25. In operation, oil is lifted, by the gear on the shaft 19, on to the ledge 52, whence some of it enters a duct in a valve-plug 54, with which a spring-raised screw-adjusted valve member 56 co-operates, and passes through other ducts, which also act as an auxiliary reservoir, to the lower end of the bore 70 in the hook shaft; the inclination of this bore raises the oil by centrifugal action to wick-filled ducts in the hook body. A helical groove 68 in the spigot of the plug 65 co-operates with the bore in the end of the shaft 25 to prevent downward seepage of oil around the spigot and to collect a certain amount of oil when the machine stops so that oil supply to the hook raceway is resumed as soon as possible after restarting; this groove may, however, be dispensed with, the spigot then being made smaller than the bore in the end of the shaft 25. and in a further modification the spigot is absent.