GB281829A - Improvements in or relating to machines for drilling metal or other materials - Google Patents

Abstract

281,829. Jones & Shipman, Ltd., A. A., and Shipman, F. Oct. 23, 1926. Drilling. - In drilling- machines of the high-speed sensitive type having a balanced spindle, a rod or stud is provided mounted on and parallel to the drill spindle, or the usual sliding bearing therefor, and acted upon by resilient means to balance the spindle during and return it after its operative movement. In one form the bearing 4 movable with the spindle 2 carries a clip or bracket 3 to which is attached a plunger 1 acting through a head 7 on a compression spring 5 located within a tubular housing 9 attached to the arm 6 through which the spindle slides, the compression of the spring being adjustable at 10. The spring may be replaced by pneumatic means, the plunger then acting as a piston so as to compress air on one side and create a vacuum on the other side or perform either function. The clip 3 may be arranged above the arm 6, the plunger then extending downwards and the spring may act on a lug instead of being located in a recess. In a modified form two or more resilient means are arranged to act telescopically so as to provide a longer stroke of the spindle. According to an example of this form the spring 5 acts on the closed lower end of the housing 9 and the latter is provided with an external flange at the top which acts on a surrounding spring located within a recess in the arm 6 and bearing against a flange secured against the bottom of the recess. In another form the resilient means take the form of a rubber &c. tube filled with air whose pressure is controlled by a pump and valve. this form being stated to be particularly useful for small machines.