Patent GB-982962-A (GB)
Title: Improvements in or relating to drafting mechanisms for spinning machines
IPC: D01H5/56
Filed: 1962-10-31
Abstract: 982, 962. Drafting mechanisms. SKF KUGELLAGERFABRIKEN G.m.b.H. Oct. 31, 1962 [Nov. 22, 1961; Feb. 15, 1962], No. 41256/62. Heading D1D. Drafting mechanism comprises a lop roller carrying and weighting arm mounted on a fixed pivot for movement between operative and inoperative positions, and a locking mechanism for releasably holding the arm in said positions comprising an operating-lever pivoted to the arm to swing between first and second positions corresponding to the operative and inoperative positions of the arm and a locking-member mounted to swing about a fixed pivot between first and second locking positions, means to effect movement of the locking member between these positions, the operating-lever and the locking member having features which engage in their first positions to provide an over-dead-centre lock preventing movement of the arm from its operative position, and the arm and the locking-member having features which engage in the inoperative position of the arm and the second position of the locking- member to lock the arm in inoperative position. Each weighting arm 7 is of U-shape and is pivoted at 6 in two spaced plates 2 fixed on a common rod 1, the plates having connecting pins 4, 4<SP>1</SP> and a bar 5 the latter carrying a set screw forming the connection with the rod 1. The operating arm 16 has a tail 16<SP>1</SP> depending between the plates which is pivotally mounted on a pin 17 carried by the arm. The locking-member comprises two plates 20 pivoted at 19 in the fixed plates and urged by a spring 22<SP>1</SP> to rotate anti-clockwise. The arm is held in operative position, Fig. 3, by the engagement of a pin 18 on the tail 16<SP>1</SP> in a recess 21 in the locking member; the tendency of the arm to rise under the influence of the weighting- means is resisted because the pin 18 tends to rotate the locking member anticlockwise against the fixed pin 4<SP>1</SP>. With the arm in this position, the pin 18 lies to one side of the line joining the pivots 17, 19, constituting an over-dead-centre lock. To release the arm, the lever 16 is raised, taking pin 18 out of the recess so that spring 22<SP>1</SP> rotates the locking-member 20 anticlockwise so that its upper end strikes pivot 17. Arm 17 is now free to rise under the influence of the weighting springs and can be relocked by depressing the lever 16 or raised into an operative position where it is again locked. For this, lever 16 is further raised, pin 18 entering a recess 24 in the arm 7 so that arm and lever rise together until, finally, pin 17 enters recess 21, Fig. 5, a spring 25 being thus tensioned. To return the arm to operative position, the lever 16 is depressed so that a shoulder 26 bears against a pin 23 to rotate the locking member and move the recess 21 clear of pivot 17. The arm 7 is thus unlocked for downward swinging which occurs either by its own weight or the force of spring 25 which was previously tensioned. Downward movement is completed by lowering arm 16 until pin 18 moves out of notch 24 into notch 21. In another form, Fig. 8, the tail 16<SP>1</SP> is of U- section, is pivotally connected to arm 7 at 29 and carries a pin 28. The locking-member 30 comprises a number of plates fastened together is pivoted to the plates 2 at 31, and has a slot 32 receiving the pin 28 where a spring 36<SP>1</SP> tends to rotate it anticlockwise. In the inoperative position of the arm shown, the pin 28 lies in a recess at one end of the slot 32 so that the member 30 is locked against rotation by spring 36. To raise the arm, lever 16 is raised, moving pin 28 out of the recess and allowing the member 30 to rotate until a cam-surface 33 engages a roller 35 on the arm. As the lever further rises, the roller rides over the cam until it enters a notch 34, pin 28 moving to the opposite end of the slot when the arm is held in its inoperative position, upward swinging being limited by stops 37 on the plates 2. To restore the arm to operative position, lever 16 is depressed to rotate member 30 so that the notch 34 moves clear of roller 35, when the arm is freed to be rotated downwardly; as the operating lever is further depressed, roller 35 maintains contact with the cam; finally the lever 16 reaches contact with the arm and the pin 28 reaches its starting position in the recess in the slot 32 where it is in an over-dead-centre position relatively to pivots 29, 31. Various modifications may be made in the structure and arrangement of the parts: in particular, the slot 32 may be in the tail 16<SP>1</SP> and the pin 28 on the member 30.