GB926660A - Improvements in or relating to machine tool feed apparatus - Google Patents

Abstract

926,660. Drilling. BALDWIN INSTRUMENT CO. Ltd., and C. H. HAY. Oct. 14, 1959 [July 3, 1958], No. 24674/58. Class 83 (3). A machine tool comprises a linearly movable cam 42 moved with the tool carrier by a fluidpressure operated piston-and-cylinder assembly 14, 15 to control the inlet to, or outlet from, the cylinder. A chuck 11 is rotated by a vane-type motor in a base 10 driving through change-speed gearing in a casing 12. A member 24 moves a valve 20 to supply air to feed the chuck 11 or releases the valve so that it is moved by a spring 23 to return the chuck, the supply to each end of the cylinder beingthrough screw.adjusted needle valves. The exhaust from each end of the cylinder takes place through valves 33, 34, Fig. 4, adjustable by screws 69, 70. Each valve has an exhaust inlet 35, Fig. 9, and a tapered plunger 37 moved against a spring 38 by the cam plate 42 acting directly on a follower 62 or through a plunger 64, a lever 65 and a plunger 66. The cam plate 42 is supported on a slideway 45 attached to a flange 17 moved with the tool. A pin 47 on the cam plate slides in a slot in a plate 49 pressed by springs 50 to keep an adjustable abutment 53 in contact with a trigger valve 55. When the pin 47 reaches the end of the slot it pulls the abutment 53 away from the valve. The valve releases the pressure behind the member 24 allowing the spring 23 to reverse the valve 20 and return the tool. As the drill returns, the abutment 53 closes the valve 55 and pressure again builds up behind the member 24 at a rate controlled by a further needle-valve. The piston 15 may be returned by a spring as in Specification 868,816. It is stated in the Provisional Specification that the tool may be a drill.