GB1223957A - Drilling apparatus - Google Patents

Abstract

1,223,957. Drilling machines; grinding. LIBBEY OWENS-FORD CO. 10 June, 1969, No. 29261/69. Headings B3C and B3D. A cycle of operations in a machine for drilling a plurality of holes at exact predetermined locations in a sheet of glass S by tubular drills 106 with cutting ends of fine diamond powder in a suitable matrix, is initiated when the sheet S is placed on a protective layer 47 carried by a base member 43 of a drill jig 21, so that the edge contacts locator means 65, 66 and 67 and puts control means 75, 76 and 77 in a circuit-closed condition. This causes valves (145) and (151), Fig. 12 (not shown), to direct pressure to cylinders 142 and 112, respectively, thereby lowering clamping devices 135 as first drilling means 104 are moved upwardly to perform the first phase of the drilling operation. When the desired depth has been reached. Fig. 10 (not shown), individual control means 155 are engaged to produce reversal of valves (151) so that drills 104 are retracted. Control means 155 causes the opening of the "series" circuit through control means 75, 76 and 77 which circuit would otherwise be maintained throughout the entire drilling operation. Also, the control means 155 causes operation of valves (181) to produce a downward stroke of second drilling means 105. As the spindles 110 are lowered from the position of Fig. 7, leg 197 of each actuator element 183 is removed from engagement with finger 212 of control means 176, 177 and 178. At this time there is no active circuit to these series control means 75, 76 and 77. However, when the drills 106 complete the formation of holes in sheet S. the completion of circuits is produced by circuits through the individual control elements 175. Each control element causes its drilling tool 105 to retract after which a circuit is completed through the control means 176, 177 and 178. At the upper limit of spindles 110, when all the legs 197 engage fingers 212, the valves (145) are reversed to lift the clamping devices 135, after which valves 215 are made operable to actuate adjustably mounted ejector devices 99. The discs 222 of these devices are moved with sufficient thrust to move the sheet from the drill jig 21 and cause it to drop on to the conveyer belt 16. The line circuit to "series" control means 75, 76 and 77 is re-established, the line circuit to "series" control means 176, 177 and 178 is again opened and valve 215 is actuated to retract the discs 222 of ejector devices 99. To prevent excessive movement of an upper drill 106 in the advent of a failure of control means 175, a nylon washer 203 mounted on a stationary block 128 and lock-nuts 204 and 205 positioned on spindle shaft 124. Each pair of drills is mounted in a housing 26 which is adjustably positioned on a base structure 36.