GB1164502A - Device for Assisting in the Manipulation of Appurtenances, Controls or the like Associated with Sewing Machines - Google Patents

Abstract

1,164,502. Sewing machines. SINGER CO. 23 Jan., 1967 [7 Feb., 1966], No. 3311/67. Heading D1G. Means for assisting in the manipulation of an appurtenance shiftably, supported on a sewing machine and operatively connected to an operator-influenced linkage, comprises valve means carried by said linkage, means for providing a predetermined amount of lost motion in said linkage to operate the valve means, a fluid pressure-operated drive member operatively connected to the appurtenance, .and conduit means interconnecting the drive means and valve means with a source of fluid under regulated pressure. As shown, a presser bar 14, carrying a presser foot 13, is operatively connected to one end 20 of a lever 21. End 20 may be raised by a hand-operable lever 23 to lift the presser foot against the bias of a spring 15. The other end 26 of lever 21 is connected by a pull rod 28 to one arm of a lever 31 pivoted on a bracket 33 within a lubricant collecting pan 12. The other arm of lever 31 is connected by a push rod 35 to an arm 39 pivoted on a bracket 37 depending from pan 12. A depending rod 40, rigid with arm 39, passes through a bore in a block 50, the latter being adjustably secured to rod 40 by a screw 71. A slot in block 50 houses a valve (51) secured in position by screws 73. The inlet of valve (51) is connected by a conduit 52 to a pressure-regulating valve 53. The outlet of valve (51) is connected by a conduit 54 to a cylinder 55, the piston rod 58 of which carries a stop nut 60 bearing downwardly on end 26. A resilient knee pad 41 is fixed to a plate 81 slidably mounted on studs 84 projecting from block 50. A compression spring 85, housed in block 50, abuts at one end against screw 87 and at the other end against plate 81 to bias the latter against the heads of studs 84. Knee pressure on pad 41 thereby serves initially to shift plate 81 along studs 84 for actuating the operating plunger 76 of valve (51). Air is then admitted to cylinder 55, the pressure being so regulated by valve 53 that the downward force exerted on end 26 by nut 60 overcomes about 80 per cent of the force of spring 15. Comparatively little additional force on pad 41 is therefore required to raise the presser foot via the pull rod 28. Valve (51) is arranged to exhaust the air from cylinder 55 on release of pad 41.