GB783384A - Sewing machine, particularly blindstitch sewing machine - Google Patents

Abstract

783,384. Sewing machines. SINGER MANUFACTURING CO. Oct 19, 1955 [Oct. 22, 1954], No. 29824/55. Class 112 In a blindstitch sewing machine the work-supporting arm 18, which is carried by pivots 33, 34 journalled in the ends of a spindle 26 fixed in the machine frame, is provided with an abutment screw 47 which is biased against a block 38, journalled on spindle 26, by means of a stressed leaf spring 44 which is secured at one end by a screw 45 to block 38 and abuts at its other end against a screw 46 carried by arm 18, the arrangement being such that block 38 may either be locked to the machine frame, when spring 44 holds arm 18 in the operative position, or block 38 may be unlocked from the machine frame, when arm 18 may be lowered against the bias of a comparatively weak spring 42. A block 39, also journalled on spindle 26, is adapted to be fixed in adjusted angular position relative to the machine frame, for which purpose an arm 48 projecting from block 49 has a pin-and-slot connection with a rod 51 slidably mounted on the machine frame and adapted to be moved axially by means of a rotatable knob 54. A recess 56 in block 39 loosely receives a lug 57 projecting from block 38 for limiting angular movement of the latter. A pin 58 slidably mounted in block 39 is biased by a spring 61 into a slot 60 in block 38 to prevent angular movement of the latter. Pin 58 is connected to a bar 79 slidably mounted on the machine frame, whereby movement imparted to bar 79 serves to withdraw pin 58 from block 38. A rod 66, journalled in a bracket 63 on the machine frame, is adapted to be rotated by means of a knee press and carries an arm 73 having a wear-resistant tip 74 which normally bears against the vertical end 89 of bar 79. Initial anti-clockwise movement of rod 66 thereby serves to move bar 79 inwardly to free block 38, tip 74 then moving over an arcuate surface 90 on bar 79 centred on the axis of rod 66. The latter also carries an arm 68 connected by links 69, 70 to arm 18, the links having a lost-motion connection, whereby no force is transmitted to arm 18 while bar 79 is being moved by tip 74, and arm 18 is moved downwardly while tip 74 is moving over surface 90, arm 18 then being free from the biss of spring 44. In a modification leaf spring 44 is replaced by a coiled compression spring.