GB888485A - Hydraulic or pneumatic picking motions for weaving looms - Google Patents

Abstract

888,485. Fluid-pressure picking motions; checking shuttles. MULLER, H. May 5, 1958 [May 4, 1957], No. 14372/58. Class 142(2) [Also in Group XXIX] In a hydraulic or pneumatic picking motion the shuttle is picked by a piston from a predetermined starting position and at the end of the return pick is checked by the piston due to throttling of the fluid forced out of the cylinder as the piston moves towards its starting position, the shuttle being further checked beyond this position by a spring which subsequently moves the shuttle forward to the -starting position. As shown in Fig. 1, a shuttle is picked by piston 20 in a cylinder 18 supplied with liquid from an accumulator 5 under the control of a slide valve 14. The accumulator is charged by a pump 2 at a pressure governed by a valve 6. In the position shown, the accumulator supplies liquid to the cylinder through lines 8, 17 to move the piston to the right. Towards the end of the stroke a piston 32 on a tail rod 19 closes a bore 38; fluid to the right of the piston 32 then passes through an adjustable throttle valve 36 to damp movement of the piston, and the stroke is limited by contact of the piston 32 with the end wall of its chamber. When the valve 14 is moved to the left, the cylinder 18 is opened to a reservoir 3 through ports 22, line 23 and a throttle valve 24. When the shuttle returns it displaces the piston, and the ports 22 (which become smaller towards the left) are progressively closed to produce a constant pressure to retard the movement of the shuttle. When the ports 22 are completely closed, liquid passes through the line 17 and a non-return valve 11 to the accumulator 5. When the line 17 is closed by the piston, liquid in the cylinder 18 passes through a bore 31 in the tail rod and through a non-return valve 27 to a chamber 29 communicating with the atmosphere through a hole 30; the tail rod engages a buffer 42 which compresses a spring 41 until the piston stops. The spring 41 thereupon moves the piston and shuttle back to the starting position, the movement being damped since the liquid which is forced from the chamber 29 to the cylinder 18 by the-pressure of the atmosphere is throttled by a valve 28. In the embodiment of Fig. 2, the shuttle is picked by a hollow piston 20a slidably mounted on the rod 19a of a piston 48a biased to the right-hand end position shown by a spring 41 and hydraulic pressure supplied through a line 49. Liquid is supplied through a line 17 to move the piston 20a to the right, the movement being damped towards the end of the stroke when a head 32a of the rod 19a enters a recess 43 of the piston 20a, and the stroke is limited by contact of the head with the end wall of the recess. When the shuttle returns, it moves the piston 20a to the left, expelling liquid first through a line 23 and then through the line 17, until it reaches the starting position in which it abuts a shoulder of the rod 19a. Further movement of the piston 20a moves the piston 48a against its spring and hydraulic loading, liquid from the working cylinder passing through a non-return valve 27 to the right-hand side of the piston 48a. After the leftward motion has ceased, the piston 48a is moved by its bias to its right-hand end position thus moving the shuttle and piston 20a to their starting positions. This movement is damped by a valve 28 throttling return flow of liquid from the right-hand side of piston 48a. In a modification of this embodiment, the rod 19a is fixed and the piston 48a is slidably mounted on it. In all the embodiments the piston may pick the shuttle indirectly through a mechanical linkage.