Patent GB-623903-A (GB)
Title: Lubricating and guarding means for sewing machines
IPC: D05B71/00
Filed: 1947-05-27
Abstract: 623,903. Sewing-machines. SINGER MANUFACTURING CO. May 27, 1947, No. 14027. Convention date, March 4. [Class 112] Lubricating; frames.- In a sewing-machine with needle-bar and take-up mechanisms in a hollow head, two oil sumps at different ieve!s are provided in the head and wicks from these sumps convey oil to the mechanisms. A guard is provided to prevent oil from passing out through the slot in which the take-up arm acts and another guard for any other slot for other devices such as a presserbar lifting arm and a slack-thread control arm; the guards may carry the wicks. In the case of a machine of the kind described in Specification 589,995, having head inclined upwardly and rearwardly with its side open and closed by a faceplate, the latter is formed so as to deflect oil away from the joint between the faceplate and head. In the embodiment described, oil is fed, by a pump at the lower end of a vertical shaft connecting the needle-bar and loop-taker shafts, to the right-hand bearing of the needle-bar shaft 8, Fig. 1, and thence along a bore in the shaft to the left-hand bearing 5, within which the shaft has a radial duct to allow the oil to pass to the bearing surface; a helical groove in the shaft opposes movement of oil towards the lefthand end of the bearing, and any leakage from this end is carried back into the arm 3 of the machine by a duct 56. A wick 62 draws oil from the bearing 5 into a trough-like member 57 provided with depending tubes 64 with wicks through which oil passes onto the needle-bar and take-up mechanisms. A guard G, Fig. 4, as described in Specification 544,602, having an upper extension fitting round and secured to the upper needle-bar bearing 11, shields siots in the front wall of the head 4 through which pass the take-up arm 17 and a slack-thread control arm 40 fixed to the presser-bar, so that oil thrown off by the mechanisms cannot pass out through these slots ; a depending part of this guard carries a wick 72 which lifts oil from a sump in the bottom of the head 4 and wipes against the needle-bar 12. The end of the take-up arm 17 is covered by a guard 83, with slotted sides, to catch any oil passing along the arm and return it to the interior of the head 4 by a duct at its lower end. A slot in the back of the machine head 4, for the presser-bar lifting arm 46, is shielded by another guard H carrying a stiffened wick 81 to lift oil from a second sump 74 in the head, which receives oil from the mechanisms and this guard, to the take-up lever and needle-bar link to supplement the supply from the trough 57. In order to avoid leakage of oil through the joint between the face-plate F and the head 4 at the back of the latter, without the use of a gasket at the joint, which frequently has to be broken, the face-plate. is formed with corrugations 93 inclined forwardly and downwardly and a shelf 94 which leads the oil to the inside of the shield 95 secured to the head 4 and not iequiring to be detached when the face-plate is removed. Presser-bars.-The inclined presser-bar 37 is spring-loaded, and is prevented from rotation by an arm 42 engaging a groove in the machine head 4. It is lifted by a knee-or foot-operated lever 45 to which is secured a bar 46 connected by a stiff wire link 48 to the presser-bar below the collar carrying the arm 42. The presser-foot may also be lifted by a finger-lever pivoted on the head 4 and formed with cam surfaces adapted to lift the lever 45 when the finger-lever is turned to the right or the left. Threads, controlling: needles, driving.-The take-up arm 17 is mounted on a crank-pin 16 on the needle-bar shaft 8 and guided by a link 24 pivoted in the machine-head 4. A slack-thread control arm 40 fixed to the presser-bar (which is spring-pressed) engages the thread between the tension device and the take-up. The inclined needle-bar 12 is driven by a link 21 on a return crank 18 carried by the take-up crank-pin 16.