GB434676A - Improvements in and relating to rotary tool devices for drilling, grinding and like purposes - Google Patents

Abstract

434,676. Grinding. DESOUTTER BROS., Ltd., and DESOUTTER, C., 73, Baker Street, London, and WEBB, G. H., 123, Whitchurch Gardens, Whitchurch Lane, Edgware, Middlesex. May 9, 1934, No. 14030. [Class 60] [See also Groups XXII and XXVI] A rotary tool device which may be adopted for grinding having an air motor with radially slidable vanes carried in slots provided in an eccentrically arranged rotor, is characterized by the provision of a number of expansion chambers and at least one communicating passage, which is narrow but of comparatively large area, between two such adjacent chambers, thus providing for expansion of the exhaust air from the motor prior to its leaving the main casing. Compressed air passes to the hollow handle 48 through a trigger-operated valve 43 and thence along a passage 49, Fig. 4, to the crescent-shaped motor chamber 9 where the tangential jet of air impinges on the blades and rotates the rotor 11. The exhaust air passes out through a number of openings 24 into an expansion chamber 25 between the motor chamber and the outside casing, a flange 28 on the former provides a narrow space 27 of comparatively large area for the exhaust air to pass through on its way to the adjacent expansion chamber 26 and finally to the main outlet 29, this arrangement considerably reducing the noise due to exhaust air leaving the device. A sun pinion on the front end of the rotor shaft drives a tool connected to the cage 32 through planetary gears 30 carried by the cage which engage a fixed internally toothed annulus 37.