GB674207A - Improvements in and relating to method of and apparatus for drilling long holes - Google Patents

Abstract

674,207. Long-hole drilling. MOYNAHAN BRONZE CO. Feb. 27, 1950, No. 4987/50. Class 83 (iii). A method of drilling long holes in the form of precisely aligned openings through a plurality of spaced projections of an elongated workpiece, comprises precisely aligning said projections, constantly rotating and continuously feeding a drill through the spaced projections in sequence to drill aligned openings therethrough, and engaging and guiding the leading end of the drill as it passes through the spaces between the projections. The work-piece in the embodiment described comprises an elongated hinge-member 1, Fig. 10, having a bead 2 along one edge and portions milled out along the edge to provide alternate spaces and projections, with a long hole 4. The work is positioned in a V-shaped recess 10, Fig. 3, in a support 6 carried by a machine base 5. Clamping of the work is effected by a number of air-actuated piston-rods 19 carried at one side of the machine on brackets 25. Preliminary adjustment of the clamping members is effected by adjusting screws 24. Guide bushes 26, Fig. 6, are clamped by plates 27 in the V-recess 10 of the member 6 to occupy positions intermediate the hinge projections and thus to guide the leading end of the drill as it passes through the spaces. A drill head 34, Fig. 1, having a spindle 35 driven from an electric motor 32 and slidable along guides 31 is provided at each end of the machine, the drills being in axial alignment. The drill carriages 30 are reciprocated longitudinally of the bed by hydraulic double-acting cylinders 36, 50, Figs. 1 and 3, and elongated piston-rods 37 connected to the carriages by brackets 38. The free length of the drill 43 prior to the commencement of the drilling operation is supported by a series of rectangular plates 44, Fig. 9, in turn slidably supported on fixed guide-bars 40. The plates 44 are interconnected by links 46, Fig. 8, and as the drill enters the work the plates 44 approach one another, finally occupying the fully-folded condition against a front support bushing 48, Fig. 8. Solenoid-operated valves are used to control the various airpressure movements, and limit switches and a cam-controlled switch is also employed to give slow feed movements during drilling, rapid passage of the drill across the gaps in the work and a rapid drill return movement.