GB722784A - Improvements in and relating to belt grinders - Google Patents

Abstract

722,784. Abrasive band apparatus. BAKER, P. R., PLANCON, G. H., and McFALL, D. F., [trading as JONVIR MANUFACTURING CO.]. Jan. 22, 1953 [June 16, 1952], No. 1921/53. Class 60 An endless abrasive band 23 is supported between a driving pulley 15 on a power tool 9 and a pulley 25 carried by an attachment 29 capable of being mounted on the power tool, one of the pulley shafts being eccentrically mounted and connected with means permitting it to be rotated towards or away from the other pulley to facilitate replacement of the band. In the apparatus described, the attachment 29 has a split collar portion 31 which is contracted by. a screw into clamped engagement with the body of an air-operated, portable tool. The pulley 25 is mounted on anti-friction bearings on a shaft 53 rigidly and eccentrically secured to knob means 45 rotatably mounted in the attachment. A pin 77 in engagement with a groove 79 in the means 45 limits the angular travel of the latter which is urged by a spring 67 to a position in which the shaft 53 is at its maximum distance from the pulley 15. The belt 23, which is not long enough to permit the shaft to reach this position, is thus placed under tension by the spring. The cantilever loading of the shaft 53 by the tension on the belt 23 cocks and hence locks the means 45 in the attachment 29 so that accidental displacement of the pulley 25, whether or not the band is running, is prevented. In addition, the direction of rotation of the band is chosen to assist the action of the spring 67 in urging the shaft 53 to its outermost position. A ribbed rubber rim 19 may be provided on the pulley 15 or, alternatively, both pulleys may be provided with crowned rubber rims to enable either to be used as a backing pulley. The attachment 29 is preferably formed of cast aluminium, duralumin or magnesium and a hardened steel insert 41 is cast in one end to form a bushing for the means 45.