GB317872A - Improvements in, or relating to, work supporting means for drilling and other machine tools - Google Patents

Abstract

317,872. Evans, F. H. May 22, 1928. No Patent granted (Sealing fee not paid). Drilling-machines.- In means for supporting and holding the work on machines such as boring and drilling machines, the work is held on a table by one or more fluid pressure cylinders, the arrangement being such that on depressing a pedal fluid is admitted to the cylinders to grip the work, the feed motion of the tools is set into operation, and reversed, the work-holding means are released and the feed motion is automatically stopped. As applied to a drilling-machine one or more drill heads 7, each carrying a number of drills 8 rotated from pulleys 9, are mounted on a slide 12 movable horizontally to and from a work-table 4 which is angularly adjustable about pivots 6. A cross bar 18 is vertically adjustable pillars 16 secured at each end of the table and serves to support one or more laterally adjustable pneumatic cylinders 20 which contain plungers 22, Fig. 4, adapted to be pressed downwardly against springs 25. A pulley 41, Fig. 2, drives a shaft 39 through the medium of a worm drive 36 and a clutch 40, the shaft 39 having at one end a crank pin 61, Fig. 3, serving to oscillate a slotted link 62 and impart feed to the slide 12 through a link 65, levers 66, 68 on a shaft 67, and links 13. The supply of air to the cylinders 20 is controlled by a valve 78 whose plunger 77 rests on a lever 56 which is normally held in the raised position shown in Fig. 3 by a cam 54 on a disc 53 secured to the shaft 39, thus allowing air from the supply pipe 72 to pass to exhaust. In operation, depression of a pedal 30 oscillates a lever 45, Fig. 2, connected by a link 47 to the clutch operating lever 50, past a cam 43 on a disc secured to the shaft 39 and thus closes the clutch and allows the shaft 39 to be rotated. The cam 54 thereupon allows the lever 56 to fall and admits air to the cylinders 20 to grip the work and the crank pin 61 then feeds the drills into the work and withdraws them. After a single revolution of the shaft 39, the cam 54 raises the lever 56 to connect the cylinders 20 to exhaust and the cam 43 acts on the lever 45 to open the clutch 40, and bring the slide 12 to nest. The valve 78 may be arranged to admit air to the cylinders 20 in advance of the operation of the drill and to exhaust the cylinders at any predetermined period after the drills have ceased to operate. The compressed air may be supplied by a compressor driven by the machine and the work-clamp may be permanently secured to or separate from the machine and may be removably secured in any position relative to the work table. According to the provisional Specification the drill spindles are driven by universal joints from a shaft, the shaft 39 is rotated by a pinion on the clutch shaft, and the control valve 78 is operated by an adjustable rod connected to the shaft 67 of the bell crank lever 66.