Patent GB-597875-A (GB)
Title: Improvements in or relating to apparatus for cutting-off lengths of moving material
IPC: B23D45/18
Filed: 1944-02-21
Abstract: 597,875. Rolling. STEVENS, A. H. (Aetna-Standard Engineering Co.). Feb. 21, 1944, No. 3201. [Class 83 (iv)] [Also in Group XXIII] Flying cut-off mechanism comprises a carriage, means supporting the carriage for advancing and retracting movement, means carried by the carriage for severing a moving article, means other than the article for moving the carriage in advancing direction at a substantially constant speed for a portion of its travel, means for causing said severing means to operate to sever the moving article during said constant speed portion of the movement and means for retracting the carriage, the speed of the retracting means being controllable independently of the speed of the means for moving the carriage in advancing direction. The invention is described as applied to mechanism for cutting off lengths of metal tube as it emerges from a tube mill. The cutting-off is effected by a saw 21 carried by a pivoted arm 18, Fig. 11, mounted on a carriage having rollers 14, 15 and 16 by which it is supported on rails or track bars 11, 12 and 13 and on which it is constrained to move at the speed of travel of the tube during the cutting-off operation. During said movement, a roller 24 at the rear end of the arm 18 engages a cam 25, carried by the frame of the machine, which tilts the arm so that the saw 21 moves through the tube which is supported in a trough 28. After the cutting-off, the arm 18 is returned to its original position by springs 31 co-operating with shock-absorbers 44. The saw is driven by a belt 22 from a motor 19 mounted on the carriage with its axis coincident with the tilting axis of the arm 18. Longitudinal movement of the carriage is effected through a rod 67 coupled to arms 70, Fig. 14, between which is mounted a follower 75 adapted to be actuated by a cam 77 on a main driving shaft 54 which is coupled through a gear-box to the motor 5 (not shown) which drives the feed rollers of the tube mill, the gearing and the shape of the cam 77 being arranged so that during the severing operation the carriage and the tube move at the same speed. Arms 70 are connected by a rod 78 to a piston 80 moving in a pivotally-mounted cylinder 81 supplied at its lower end with compressed air. Towards the end of the advance movement of the carriage a plunger 80<1> on the piston 80 closes the air passage in the base of the cylinder and the advance is cushioned bv the residual air which escapes through a needle valve 87. The carriage is returned by the action of the compressed air on the piston 80, a needle valve 88 at the upper end of the cylinder serving to adjust the cushioning effect. During the return movement, the cam 25 which is carried by a tiltable plate 45, is moved out of the path of the roller 24 by means of a piston operating in a cylinder 50 to which air is supplied under the control of a cam 53 on the shaft 54. A more elaborate hydraulic method of controlling the position of the cam 25 is described with reference to Fig. 16 (not shown). The shaft 54 is driven through a clutch 96 controlled by a latch disc 108, Fig. 7, having a projecting lug engaging the spring-supported head 110 of a bell-crank arm 111, 118 which has a pin-andslot connection 114 with a link 113 and arm 116 keyed to a shaft 117 which is connected by means 124, 125 to the operating arm 126 of a solenoid 127, Fig. 4. When the advancing end of the tube emerging from the mill engages a switch (not shown), the solenoid is energized to rock the shaft 117, thus moving the head 110 against the action of a spring 121 to allow the rotation of the disc 108, shaft 54 and carriageoperating cam 77. The cushioning of the movement of the shaft and the positioning of the shaft is ensured by means of a second disc 128, Fig. 8, also keyed to the shaft 54 and formed with two latch portions 129, 130 engaged by arms 131 and 132 respectively. These arms are mounted on a pivoted frame 133 supported by a rod 138 and cushioning spring 140 which takes up the thrust on the frame due to the sudden stopping of the shaft 54. When the rod 117 is rocked by the solenoid, the arm 131 is first moved away from the latch 129 before the lost-motion connection 114 causes the release of the disc 108. A pin 147 carried by the frame 133 and adapted to seat in a cradle 153 under the action of a spring 150 serves accurately to position the disc 128 and shaft 54 during the rest period so that the saw carriage begins its advance movement from the same position each time.