Patent GB-505843-A (GB)
Title: Sewing machine
IPC: D05B71/00
Filed: 1937-11-17
Abstract: 505,843. Sewing-machines. FAIRWEATHER, W. C. (Singer Manufacturing Co.) Nov. 17, 1937, No. 31576. [Class 112] The feed mechanism of a high-speed lock-stitch sewing machine comprises a feed-rocker carrying an arm, a rotary shaft carrying an eccentric actuating a pitman, a link connecting the pitman to the arm and arranged at an angle to the pitman, and means for controlling the path of movement of the connection between the link and the pitman. The machine described embodies improved lubricating arrangements for the feedactuating mechanism, and improved bearing arrangements for the needledriving shaft. Fig. 2 is an underneath view of the machine. The main lower shaft 29, running in a ball-bearing 31, by which its longitudinal position is determined, and two bushes 37, 38 in transverse walls 95, 96 of the frame, is driven at the same speed as the upper shaft 16 by belt gearing 27 enclosed in a guard outside the standard of the machine. The looper 46 is carried by a shaft 43 above the shaft 29 and geared to the latter by toothed wheels 41, 42 to run at double speed ; this shaft is located longitudinally by the gear wheel 42 and a collar 44 abutting against opposite ends of its bearing bush in the frame wall 96. The feed-dog is carried by a bar 87 which is reciprocated by pivotal attachment to a substantially vertical arm 85 on a rocking shaft 57 and is raised and lowered by engagement of a slot in its other end with a stud on an arm 92 fixed to a rocking shaft 49. The shaft 49 is driven by an eccentric on the shaft 29 through a pitman 53 pivoted to an arm 51 on the former shaft. The connection between the shafts 29 and 57 comprises an eccentric 62 on the shaft 29 actuating a pitman 63 which is pivotally connected at 66 to a link 61 pivoted to an arm 59 on the shaft 57 ; also connected to the pitman 63 at 66 is a link 67 rocking on a pivot 69 which is normally stationary but is carried by an arm 68 on a spindle 71. The path of movement of the pivotal connection 66 may therefore be adjusted, to vary and, if required, reverse the movement of the shaft 57 produced by the invariable movement of the eccentric 62, by shifting the pivot 69 of the link 67 by angular movement of the spindle 71 ; the spindle 71 is adjusted and locked by means of an arm 75 on it carrying a square-headed pin 77 slidably engaging one arm of a crank 79 pivoted on the frame at 81, the other arm of the crank carrying a clamping screw projecting through an arcuate slot in the frame. The cross walls 95, 96 which carry the bearings for the shafts 29, 43, 49, 57 and the spindle 71, together with the side walls of the frame, form an enclosure and oil-bath closed at the bottom by a plate 99 formed with heat-radiating fins. The bearing bushes 37, 38 of the shaft 29 are lubricated by means of grooves 103 in, their upper surfaces extending into the enclosure, to catch oil splashed up by the mechanism, and communicating with holes leading to their bores. The bearings of the rocking shaft 57 are lubricated by inclined passages 108 in the shaft communicating with oil-catching depressions in the upper side of the shaft. In order to relieve the pressure which is developed in the lubricant-containing enclosure by high-speed operation, an axial bore 101 is formed in the shaft 49 extending from the end of the shaft to connect with a radial hole in the lower side of the shaft. The upper shaft 16 is carried in ball-bearings 14, 15, of which the latter is located on the shaft between a shoulder 24 and the sprocket-wheel 23 and is slidable in its bed in the frame standard, being pressed to the right by a spring 25 so that the crank 18 operating the needle and take-up is kept located against the bearing 14 ; this arrangement allows expansion and contraction of the shaft without affecting operation of the parts of the machine.