Improvements in or relating to sewing machines

摘要

938,706. Sewing machines. G. M. PFAFF A.G. March 12, 1962 [March 14, 1961], No. 9339/62. Class 112. In a zig-zag sewing machine the needle bar oscillation is controlled by a pack of rotary cams co-operating with followers carried by a member pivoted on an axis concentric with the axis of rotation of the cams. A pack of six pattern cams 6 is fixed to a rotary shaft 6a journalled in a base-plate 1 and driven from the arm shaft of a zig-zag sewing machine. A ring 5, mounted for rotation in a groove formed in plate 1 concentric with shaft 6a, is provided with a radial arm 4 which is connected by a link 41 to the needle bar gate. Six pins 7, which are rotatable and axially slidable in plate 1 and a spaced ring 16 carried by brackets 15, have fixed thereto arms 9 the inner ends of which can serve as followers to the respective cams. A spring 8 acting on an arm 9 biases the latter clockwise to abut a rod 11 for separating the inner end from the cam, and also biases arm 9 upwards out of adjustment with the cam. A spring 3, acting on arm 4, then turns ring 5 anti-clockwise to position a series of six pins 10 carried thereby and of various heights partly under the outer ends of the arms 9 with which the pins are associated. A knob 12, pivoted on shaft 6a and rigid with a six-lobed cam 13, is formed with a cam lug 14 adapted to co-operate selectively with the pins 7 for depressing the latter. Simultaneously with the depression of a pin a pair of lobes on cam 13 rock a pair of levers 18 pivoted on ring 16, whereby the levers co-operate with a pair of pins 17 extending upwardly from ring 5 to turn the latter clockwise. The pin 10 associated with the depressed pin 7 is thereby moved clear of the latter, and on completion of the adjusting movement of knob 12 when lever 18 engages the trough of cam 13, spring 3 turns ring 5 to engage said pin 10 with the outer end of its associated arm 9 for engaging the inner end of the latter with its associated cam. Ring 5 may be divided into two or three segments, each connected to a link controlling a function of the sewing machine, e.g. needle swing, needle mean position and work feed.