Patent GB-832785-A (GB)
Title: Hydraulic control for glass pressing machine
Inventor: BRYMER ANDREW ELLSWORTH
IPC: C03B11/16
Filed: 1956-08-22
Abstract: 832,785. Glass pressing machines. OWENSILLINOIS GLASS CO. Aug. 22, 1956, No. 25595/56. Class 56. A safety control for a glass pressing machine with a reciprocable pressing head actuated by oppositely acting fluid pressure operating means alternately communicable with a source of fluid pressure, has a valve element movable to a position at which normal communication of the means with the source is interrupted and that portion of the means urging the head in one direction only, i.e. away from pressing position, is subjected to a constant pressure to prevent reciprocation. If the source of pressure fails while the head is in pressing position, the head may be lifted away from the molten glass a short distance to be held by a ratchet device. The pressing mechanism is mounted in a head 12 on a column 11 and a removable hood 13 allows access. A series of neck moulds 17 on a rotatable carrier 16 are moved to and from pressing and blowing positions step-by-step and at pressing position, a pressing mould 20 is mounted on a vertical piston for movement to the pressing position shown, to co-operate with the pressing plunger 26. The plunger 26 is mounted on a vertical shaft 35 having a cross arm 36 at the top end a cross arm 37 at the lower end. Floating pistons 38, 39 in cavities 40, 41 in head 12 have free contact with cross arm 36 for raising the plunger 26 and similarly pistons 50, 51 in cavities 52, 53 contact arm 37 to lower the plunger to pressing position. A locking finger 56 on cross arm 36 engages with teeth 57 on the inner face of a lock bar 58 fulcrummed at 60 on head 12 and having an extension 61 in contact with a piston valve 62 and pressed upwardly by a spring 63 to vertical, locking position ; the fluid pressure through opening 75 in bracket 70 normally holding the lock bar 58 in retracted position. With failure of the fluid pressure source, the spring 63 will move the lock bar into engagement with the finger 56 at any position except the lowest position, when the head may be lifted and the lock bar engaged by the finger 56 in any desired position. For failure of any other kind, a two-way valve 123 is operated by the machine operator to cause constant pressure to the piston valve 62 and to the plunger raising pistons 38, 39 till the plunger is in its raised position, when the fluid supplied to piston valve 62 is cut off and the plunger 26 is locked by bar 58 in the raised position. Fluid pressure system. The master valve block 100 has a valve 101 under the control of a rotating cam 102 to supply pressure from a constant source 110 through line 103 to conduit 104 past pressure regulating valve 105 to line 106, and thence through ports 107 to cavities 52, 53 to lower the pistons 50, 51 and bring the plunger 26 to pressing position. To prevent hard impact with the glass, as plunger 26 approaches its lowermost position, a valve 150 is lowered to restrict the flow of fluid from cavities 40, 41, a check valve 133 causing all back flow through line 136, 136a to the control portion 164 of valve 150. At the same time, source 110 is supplying fluid pressure through lines 111, 112 and 113, that through line 111 to a valve block 120, line 121 to chamber 119 beneath a piston valve 122 in block 124 which is maintained in the up position at all times except when released by manual operation of valve 123. Line 111 also leads to line 112 which supplies pressure to the piston valve 62. At the completion of the pressing operation, rotation of cam 102 causes valve 101 to move back to the position shown in Fig. 5, so that fluid passes through line 130, past valve 122 to line 131 and valve block 120. The fluid then flows through line 132 to open check valve 133 and thence through line 134 to ports 135 in cavities 40, 41 to move pistons 38, 39 upwardly and with them the crosshead 36 and plunger 26. Fluid in cavities 52, 53 flows back through ports 107 and line 106 to check valve 106a, line 104 and out through port 100b in valve block 100. At any point in the operating cycle, the operator may, by moving the two way valve 123, discontinue the pressure from source 110 to line 111, permitting the fluid in lines 103, 111, 112 and 121 to drain back to a sump through line 123a and release the pressure on valves 122 and 150 and on pin 62, so that valve 122 moves downwardly to close the lead line 130 and allows the fluid to pass through line 113 to line 131 and around valve 150 to line 132. Check valve 133 is depressed by the fluid which flows to line 134 into cavities 40, 41 to raise the plunger 26 to the up position where it is held by the lock rack 58 pressed into position by spring 63 as the pressure on pin 62 is released. Control of plunger. To cushion the last part of the rapid down stroke of the plunger 26, the valve 150, which is maintained in the up position by fluid pressure from line 111 through port 153 on the flat end of rod 151 in the cylinder 152, is moved downwardly by a lever 160 on the cross arm 36 as the plunger 26 approaches the end of its stroke, the valve 150 then restricting the flow of fluid through lines 131, 132. A flat surface 164 on the outer cylindrical surface portion 165 of the valve 150 permits a continued but restricted exhaust of fluid and prevents any high impact force of the plunger 26 upon the glass.