GB990196A - Improvements in or relating to drilling and boring machines - Google Patents

Abstract

990,196. Drilling machine details. G. & D. DONALDSON Ltd. June 10, 1963 [June 14, 1962], No. 22806/62. Heading B3C. A single or multi-spindle drilling or boring machine comprises an hydraulic feed for the, or each, drilling or boring head 24, an electromagnetic direction control valve 27, a manually adjustable flow control valve 30, and an electromagnetic by-pass valve 31, in the hydraulic circuit for each head, the electromagnetic valves being controlled automatically by switch means 40, actuated by movement of the drilling spindle 10 in the quill 12. Each head 24 carries a quill 12, and a spindle 10 rotatable in the quill and driven from an electric motor and a gear-box, through a universally jointed shaft 15. Spindle 10 has an end float in the quill under the influence of a spring 16, and a push-rod 17 slidable in the quill actuates micro-switch 40. Head 24 is fed by an hydraulic ram 20a, the fluid flow being controlled by valves 27, 30 and 31. In operation, direction control valve 27, by-pass valve 31, and flow control valve 30, are opened, and head 24 moves towards work x at a fast speed. As drill 11 contacts the work, switch 40 is actuated to close the valve 31, and the head advances at a reduced cutting feed, determined by the setting of the valve 30. As the drill breaks through, switch 40 is opened, to open valve 31, and reverse the flow through valve 27, thus retracting the head 24 at a fast speed. At the end of the stroke, a dog on the head actuates a further micro-switch to stop the head.