| 摘要 |
1437641 Drilling machines ENGELHARD MINERALS & CHEMICALS CORP 29 March 1974 [29 March 1973] 14178/74 Heading B3C A drilling machine having a control arrangement for driving a drilling tool through an operating cycle of reciprocating travel including an interval of drilling into a sheet of glass, the control arrangement comprises a fluid cylinder, a piston therein connected to the drilling tool, fluid pressure means connected to the cylinder to extend the tool at a constant feed rate interval of fast travel up to a position close to the surface of the sheet and a constant feed rate interval of slow travel from said position to a predetermined depth of cut into the sheet and, adjustable timing means connected to the fluid pressure means for controlling the duration of the constant feed rate time intervals whereby to control the positions of the tool at the initiation and termination of said extension time interval to control the depth of cut into said sheet. As shown spindles A and B are reciprocated by fluid cylinders 15, 16 respectively. Spindle B is cycled first followed by spindle A. A sheet of glass is clamped to table 20 by jaw 24 which is operated by cylinder 27. The pressure of the jaw is greater during drilling by spindle B than for drilling by spindle A. The feed rates and periods are determined by digital timers and adjustable flow restricters. |
