GB594435A - Improvements in or relating to portable, power-operated scraping machines - Google Patents

Abstract

594,435. Scraping. ASPEEK, R. J. June 14, 1945, No. 15064. [Class 83 (iii)] A portable power-operated scraping tool comprises a blade 38 in a holder 36 and a flywheel 21 of substantial mass having an adjustable eccentric crank-pin 32 set at a small angle to the axis of rotation and connected by trunnions 34 to the holder 36 so that the blade is reciprocated, oscillated from side to side and is also rocked to give a " feathered " appearance to the scraped surface. The fly-wheel has a shaft 22 held in spaced ball-bearings 26, 27 by a bolt 24 and sleeves 23, 25 and is driven by a friction cone 20 on a shaft 14 connected to a flexible drive 19. The holder 36 is mounted on a single ball 40 placed between a pair of V-grooves 41, 42 and is held against the ball by springs 43. The blade has an arcuate cutting edge and may be tungsten-tipped; though only one half of the cutting edge operates during the cutting stroke, it is preferably symmetrical to enable the blade to be turned over to use the other half. In a modified form, the eccentricity of the crank-pin imparts the rocking movement and its inclination imparts the reciprocation and' there is no side-to-side movement. A fly-wheel D rotating on an axis eccentric to its axis AA has an inclined crankpin OB which is journalled at O in a link OC passing through a hole in a ball F mounted in a cage on a rod E. The change in position of the angle BOC, which is fixed in size, to the position B<1>OC<1> causes the reciprocation of the rod E and the gyratory movement of the point O causes the rocking.