Patent GB-1020387-A (GB)
Title: Improvements in and relating to press feed mechanisms
IPC: B21D43/11
Filed: 1963-03-15
Abstract: 1,020,387. Metal strip feeds. POWER CONTROL PRODUCTS Inc. March 15, 1963 [March 15, 1962], No. 10476/63. Heading B3W. A reciprocating gripper mechanism for incrementally feeding strip stock comprises bracket means for adjustably carrying the forward end of the mechanism over the press-bed and supporting a pair of channel members in spacedapart relationship, a stationary jaw secured transversely between the forward ends of said channel members, the underside of the jaw being co-planar with the underside of the channel members, an end plate secured between the rearward ends of the channel members, a movable jaw slidably carried between said channel members with the longitudinal axis of the jaw transversely of the members and the underside of the jaw co-planar with the underside of the members, and an actuating piston or cylinder assembly, one part of the assembly being attached to the end plate and extending rearwardly thereof and the other part being connected to the movable jaw above the plane of the underside of the channel members for reciprocating movement of the movable jaw. The assembly comprises two channel members 12, an end plate 13, a stationary jaw 14, a movable jaw 15, two brackets 16 each supporting an adjustable member 51, and two clamps 17. The jaw 14 and the plate 13 are secured to the channel members 12 and a pair of tubular members 20, 21, Fig. 2 (not shown), positioned within the channel members and extending between the jaw 14 and the plate 13 carry the movable jaw 15 and stroke adjustment bar 77 which can be clamped at any position along the tubular members. The movable jaw comprises a base portion 27 having bushed holes at each end to accommodate the tubular members 20 and 21, and a cavity 31 in its upper surface, Fig. 4 (not shown). The cavity is covered by an elastomer sheet 32 which is clamped by a plate 33 having a rectangular hole therethrough to receive a piston 35. Air pressure applied through a tube 36 lifts the piston 35 to clamp a workpiece against an upper jaw 40 of U-section, which is secured to the base portion 27 by bolts 42. Removable shims between the parts 27 and 40 allow the gap between the piston 35 and the jaw 40 to be adjusted. The fixed jaw 14 is of similar construction and receives air through the tube 20. The movable jaw only carries a work guide comprising a threaded rod 162 attached to the upper jaw 40 by brackets 160 and supporting a pair of roller assemblies 162. The actuating means for the assembly comprises an air cylinder 60, a control valve 61, and four tie rods 65, the cylinder being clamped between the valve assembly 61 and the end plate 13. A guide roller 66 is mounted in a bracket 67 which is also secured by the tie rods. The movable jaw is connected to the piston 74 by a rod 75 which also passes through the stroke adjustment bar 77. Coarse adjustment of the stroke is obtained by positioning the bar along the tubes 20 and 21 and fine adjustment by a threaded bush 85. The control valve 61 (Fig. 7 (not shown), comprises a body 92, end caps 100 and 102 and two valve spools 142, 143. Pressure air is admitted to the body by a port 129 and distributed to the centre of the bores 97 and 98, which respectively contain the valve spools 142 and 143. The body also has four exhaust ports 125, 126, 127 and 128. The valve in the bore 97 controls the actuating cylinder 60 and a port 90 leads air to the head end of the cylinder, while a port 91 leads air to the rod end of the cylinder. The valve in the bore 98 controls the clamping action of the jaws and a port 105 leads air to the stationary jaw, via a manually operated valve 108 which connects the port to atmosphere. The port 106 leads air to the movable jaw via a coupling member 111. This coupling member reciprocates with the movable jaw and also serves as a means of mechanically opening a poppet valve 112 which is secured by a bracket 113 to end plate 13 such that when the movable jaw 15 is almost at its extreme forward position the coupling 111 opens the valve 112. The outlet from the valve 112 is connected by a conduit 114 to a port 115 formed through the end cap 100 into the valve bore 98. The opposite end of the bore 98 is connected by a port 116 and a conduit 117 to a poppet valve 118, Fig. 8 (not shown), which is opened to atmosphere by a cam mounted on the crankshaft of the press and operated once in every revolution of the crankshaft. A restricted passageway 154 connects one end of the bore 97 to the port 105 and a restricted passageway 155 connects the other end of the bore 97 to the port 106. The pressure port 129 is also connected to the ports 115 and 116 via small passages 131 and 133 respectively. Operation.-The valve ports are assumed to be in the position shown in Fig. 7, with the movable jaw 15 at mid-stroke and the crankshaft positioned so that the valve 118 is closed. Pressure air from the port 129 then passes through the passages 131 and 133 to the ports 115 and 116. Air also passes through the groove 150 in valve spool 143 to the port 105 to cause the stationary jaw 14 to clamp a workpiece. The movable jaw is in the released condition since the port 106 is connected to the exhaust port 128. The head end of the cylinder 60 is connected to atmosphere through the exhaust port 125 and pressure air is applied to the rod end so that the piston 74 moves towards the head end of the cylinder until stopped by the engagement of the movable jaw with the stroke adjustment bar 77. No further action then occurs until the poppet valve 118 is opened by the cam on the crankshaft which releases the pressure in the port 116 so that the valve spool 143 moves into engagement with the end cap 102 so that the stationary jaw 14 is released by exhaust of air through the port 127, and pressure air is connected to the movable jaw 15 through the groove 150 and the port 106. When the pressure in the port 106 rises, air passes through the restricted passage 155 and after a short delay moves the valve spool 142 to engage the end cap 100. This opens the rod end of the cylinder 60 to exhaust through the port 126 and admits pressure air to the head end of the cylinder through the groove 145 and the port 90 so that the piston 74 moves forward until the coupling 111 opens the valve 112 and opens the port 115 at the end of the valve bore 98 to atmosphere, so that the valve spool 143 moves to engage the end cap 100. This movement causes a release of the movable jaw 15 and a clamping action of the stationary jaw 14 via the port 105. Air under pressure from the port 105 passes through the restricted passage 154 and after a short time delay causes the valve spool 142 to move to engage the end cap 102 so that pressure air is applied to the rod end of the cylinder 60 and returns the movable jaw to the limiting position determined by the bar 77. The cycle of operations continues automatically.