Patent GB-1015903-A (GB)
Title: Device for the disengagement, engagement and micrometric adjustment of the connection between a cam and a regulating member of a sewing machine
IPC: D05B27/22
Filed: 1962-12-11
Abstract: 1,015,903. Sewing machines. NECCHI S.p.A. Dec.11, 1962 [Jan. 3, 1962], No. 46651/62. Heading D1G. In a sewing machine, means for starting and stopping the feed and for effecting a fine adjust*. ment of the feeding movements of a feed dog comprise a member adapted to regulate the feeding movements of the feed dog, a first lever connected to said member and biased by spring means into engagement with a feed-regulating cam, a second lever on which the first lever is pivoted and which is pivoted on the machine frame, a link slidably connected at one end to the second lever and pivoted at the other end to a first operating member eccentrically with respect to the pivotal axis of the latter, a second operating member pivoted to the machine frame co-axially with respect to the first operating member, said one end of the link being guided in a slot formed diametrically of the second operating member on rotation of the first operating member, and the second operating member being rotatable between two end positions, in one of which positions the first lever is disengaged from the cam by the spring means and is engaged with a stop surface. A sewing machine feed dog 1 is carried by a feed bar 3 to which feed lift movements are imparted by a cam 5 on a rotary shaft 6. A pin 7, fast with the feed bar, is pivotally and slidably mounted in the forked end 9 of a crank 10 fast with a shaft 11, oscillation of which thereby serves to impart feeding movements to the feed dog in the direction X<SP>11</SP>. Pin 7 is pivoted at 14 to a lever 15 pivoted at one end to the machine frame and at the other end to one end of a lever 19. The latter is pivoted to a pin 21 (Fig. 2, not shown) fast with a bar 22 slidable in the arms of a U-shaped member 25 fast with a pin 27 pivoted on the machine frame. An arm 32, rigid with member 25, carries a follower 31 (Fig. 2) co-operating with a cam 33 (Fig. 2) on shaft 6, whereby member 25 is continuously oscillated. If pin 21 is aligned with pin 27, no movement is transmitted to lever 19, but progressive lateral displacement of pin 21 results in progressively greater feed advance movements being imparted to the feed dog in the direction "y". The other end of lever 19 is forked to receive a pin 38 on one arm 40 of a lever 37 which is pivoted on a pin 42 carried by one arm of a lever 52 pivoted at 53 on the machine frame. The other arm 41 of lever 37 carries a follower 47 cooperating with a rotary cam 48 for varying the lateral position of pin 21 relative to pin 27. The other arm of lever 52 is formed with a slot 60 engaging a pin 62 carried by the outer end of a link 57, the inner end of which is pivoted to a pin 63 carried eccentrically on the lower end of a cylindrical member 59 journalled in a sleeve 69 which is journalled in a fixed bushing 70. The outer end of link 57 engages parallel surfaces 67, 68 (Fig. 5, not shown) formed diametrically of sleeve 69. A spring washer 75 is positioned between an operating knob 71 fast with member 59 and a handle 72 which is splined at 73 to sleeve 69, the arrangement thereby being that a shoulder of member 69 is biased against the lower end of bushing 70, said shoulder is being formed with an arcuate groove provided at each end with a notch which may be engaged selectively, upon turning of handle 72, with a projection on bushing 70. In turning handle 72 to one end position, pin 62 cooperates with slot 60 for turning lever 52 to a position such that a spring 49 disengages lever 37 from cam 48 and engages an abutment 84 on lever 52, while pin 21 is aligned with pin 27, and the faces 67, 68 are aligned with slot 60. Turning of knobs 71 then moves pin 62 in slot 60 without moving lever 52. In turning handle 72 to the other end position, the faces 67, 68 are positioned at right angles to slot 60, and spring 49 engages lever 37 with cam 48. Turning of knob 71 then serves to turn lever 52 for varying the position of the fulcrum pin 42 of lever 37 and thereby modifying the basic feed movements imparted by cam 48 in the direction "y". Specification 952, 494 is referred to.