Drive mechanism for feed dogs of sewing machines

摘要

981, 664. Sewing machines. G. M. PFAFF A.G. Aug. 2, 1963 [Aug. 8, 1962], No. 30655/63. Heading D1G. A feed dog-actuating eccentric is carried at one end of a lower drive shaft for the looptaker, and co-operates with a bar having a pair of members which embrace the eccentric and are interconnected by a bridge member provided with a pin substantially coaxial with said shaft, a block pivoted on said pin being slidable in a slot provided in a member which is angularly adjustable for controlling the feed. A lower shaft 10, driven by a chain 9 from the arm shaft, carries an eccentric 17 embraced by arms 18, 19 on one end of a bar 20, the other end of which is pivoted to a crank 28 on the feedadvance shaft 29 for a feed dog 16. Arms 18, 19 are interconnected by a bridge member 21 carrying a pin 22 which is substantially coaxial with shaft 10 and on which is pivoted a block 23 slidable in a slot formed in a member 24 pivoted by a pin 25 on the machine frame. An arm 35 or member 24 is connected by a link 36 to one end of a doublearmed lever 38 rigid with a pivoted shaft 40. The other end of lever 38 is disposed in a cam slot 41 formed in a pivoted disc 42, and is normally biased by a spring 45 against the outer, forward feedcontrolling edge 43 of slot 41. Said other end may be transferred at any time to the inner, reverse feed-controlling edge 44 of slot 41 by manipulation of a handle 46 rigid with shaft 40.