Patent GB-1175707-A (GB)
Title: Stock Advancing Device for Punch Presses and the like
Inventor: SCRIBNER ALBERT WILLIS
IPC: B21D43/11
Filed: 1967-03-17
Abstract: 1,175,707. Metal strip feeds. A. W. SCRIBNER. 17 March, 1967 [25 March, 1966], No. 12508/67. Headings B3B and B2W. Areciprocating gripperstock feeding apparatus comprises a main frame including a main body member 20, a feed head 23 reciprocable on the frame, a stock gripper 34 mounted on the feed head, a stock clamp 35 mounted on the body, a first fluid motor for reciprocating the feed head, a second fluid motor for actuating the stock gripper, a third fluid motor for actuating the stock clamp; first, second and third conduits connected to the corresponding motors and to a control valve which applies pressure fluid simultaneously to all three motors to effect movement in one direction of the feed head and exhausts fluid simultaneously from all three motors to effect the other stroke of the apparatus. The feed head 23 slides on rails 21 secured to the body 20, its movement being limited in the feeding direction by the body and in the return direction by an adjustable screw 26. The feed is secured to the piston rod 51 of a piston 61, Fig. 6, which slides in a cylinder 60 formed in the body. The gripper 34 comprises a bar 37 which is secured to the piston rods 38, Fig. 3, of pistons 39 sliding in doubleacting cylinders formed in the feed head. The undersides 43 of the pistons are connected by a conduit 42 and hence by a tube 53 and a passage 57 to the control valve. The clamp 35 similarly comprises a bar 70 mounted on the piston rods of two single acting pistons which slide in bores formed in the body. Springs under the pistons bias the bar 70 to an upper position in which it is clear of the stock. and the upper sides of the pistons are connected together and to conduits 76, 76a which communicates with the passage 57. A further conduit 64 connects the left-hand end, as seen in Fig. 1, of the cylinder 60 to the passage 57. The conduits 42, 76, 76a and 64 are all connected to one side of the control valve. The righthand end of the cylinder 60 and the upper side of the pistons 39 are permanently connected to the source of fluid pressure so that the apparatus is biased to a condition in which the clamp 35 is raised clear of the stock by its spring loaded pistons. the gripper 34 is engaging the stock and the feed-head is abutting the body 20. As the machine operates the valve is moved to a second position in which the pressure fluid is admitted to the conduits 42, 64, 76 and 76a and since the fluid is then acting on both sides of the pistons 61 and 39 the force on the annulus side of the piston will be less than the force on the full diameter side. The clamp 35 therefore closes on to the stock, the gripper 34 opens and the feed head is moved towards the screw stop 26. Control valve construction. Fig. 11.-A vertical bore 100 in the body 20 receives a valve head 106 which is connected to a stem 107 slidable inside a valve sleeve 105, which itself slides in a block 102 fastened to the body 20. There is a compression spring 112 between the head of the stem 107 and a cap 113 screwed on to the sleeve. An exhaust port 114 opens into the annular space between the lower end of the sleeve and the upper surface of the valve head 106. A passage 116, 117, 120 and 121 which also opens into the space is connected to the conduits 64, 76 and 76a and by a passage 57 to the conduit 42. The upper surface of the valve head carries a sealing ring which engages the block 102 and the head itself has four axial grooves in its edge which permit fluid to flow by the head. The chamber under the valve head is permanently connected by an aperture 107 and a conduit 84 to the pressure fluid source, so that the valve head is maintained in a raised position. Valve operation.-With the valve in the normal raised position the conduits 42, 64, 76 and 76a communicate with the exhaust port 114. As the machine operates the cap 113 is depressed and moves the sleeve 105 down to close the exhaust port. When the spring 112 is fully compressed, the stem 107 and the valve head 106 move downwardly so that the sealing ring moves away from the block 102 and air passes by the four axial grooves to the passageway 116, 117, 120, 121 and hence to the conduits 57, 64, 76 and 76a, so that the clamp 35 is lowered on to the stock, the gripper 34 is raised and the feed head moves to the right.