GB731643A - Improvements in or relating to saws - Google Patents

Abstract

731,643. Sawing. DELETAILLE, E. A. A. L. July 3, 1953 [July 4, 1952], No. 18541/53. Class 145. A reciprocating log Saw having a single blade or ganged blades is driven by a hypocycloidal gear mechanism comprising a driven crank disc 2 with a crank pin 3 on which the planet wheel 4 rotates in engagement with a sun wheel 5 rigidly mounted in a casing 1 and the pitch diameter of the planet wheel 4 is half the pitch diameter of the sun wheel 5 so that a sleeved crank pin 6 on the planet wheel imparts a straight-line reciprocating motion to the blade or blades. A balance weight 10 is fitted on the disc 2 and another balance weight 11 is fitted on the planet wheel 4. The saw may comprise a pair of pillars 14 on which a cross member 15 is vertical adjustable and a single gear mechanism may operate a saw frame sliding on the member 15 or a pair of mechanisms 21, 22 connected by a chain drive 28 may have sleeves 30 carrying one or more blades fitted on their crank-pins. For tensioning the blades, one mechanism may be adjustable on the cross-member by a screw 24 and locked in adjusted position by bolts 27. In the vertically-arranged saw shown in Fig. 6, a blade-carrying frame 32 is reciprocated by a pair of mechanisms 34, 35 connected by a gear drive or by four driving mechanisms, two at the top and two at the bottom of the frame, or by a single mechanism. The interconnection of the mechanisms, so that they run in synchronism, may also be by means of coupling rods or by electrical or electronic means. Where pairs of mechanisms are used, they may be arranged slightly out of phase so that the blade oscillates slightly during reciprocation to prevent jamming in the kerf; with this arrangement, the distances between the two crank pins will vary during reciprocations but the variation is small enough to be within the elastic deformation range of the blade.