GB898012A - Improvements in or relating to a sawing machine - Google Patents

Abstract

898,012. Sawing. KIVIMAA, E. M. Aug. 21, 1959 [Aug. 21, 1958; June 18, 1959], No. 28600/59. Class 145. A saw blade 7 or set of blades is mounted between levers 3a, 3b oscillated by a crank rod 15 and the curved motion of the blades is straightened or otherwise modified by guide members 23a, 23b or 26a, 26b acting on pivotal linkages 20a, 20b connecting the ends of the levers to blade holders 6a, 6b. In Fig. 3, the guide members 23a, 23b are fixed plates and one or two rubber-covered rollers 21 on the top link 20a and a curved sector 22 on the lower link 20b bear against and roll on the plates. The blade will be relieved on the return stroke by yielding backwards and may also, by movement of the guide plates, be given a motion perpendicular to and in synchronism with the main reciprocation so as to cut a chip of even thickness during the entire working stroke. The guide plates are arranged to give a forward inclination to the blade and may be connected to the work feed controls so that this inclination changes automatically on changing the feed speed. The blade is tensioned by telescoping arms 9a, 9b connected to levers 4a, 4b on the shafts 2a, 2b of levers 3a, 3b, the arms having an adjusting member 10a screwed on the arm 9a, a member 10c with a pin 10d in an oval hole in the arm 9b and a rubber cushion 10 between them. The flexible cushion 10 may be replaced by a flexible device on one or both links 20 or blade levers 3a, 3b or between the levers 3a, 3b or 4a, 4b and the shafts 2a, 2b. In Fig. 5, guide rods 26a, 26b which are much longer than the levers 3a, 3b are pivoted to the blade holders and pass through shafts 28. Nuts 30 on the ends of the rods are adjusted to draw the blade back a little from the position it would otherwise occupy between the two levers. Where several blades are fitted, they are secured frictionally in a member 6b, Fig. 6, in the bladeholder 6a by distance pieces 18 which are compressed from the side by one or more screws. The distance pieces and the blades may be roughened to increase the holding effect. The work may be fed by hand, by a chain or belt or on a carriage 32, Fig. 9, moving on rollers 31 and having a guide tongue 32a engaging in a groove 31a on the rollers. The carriage may move backwards and forwards or a number of carriages moving in a circular path may be used.