GB1240924A - Reciprocating saws - Google Patents

Abstract

1,240,924. Frame saws. THOMAS ROBINSON & SONS Ltd., and R. H. BUCKLEY. 9 June, 1970 [25 June, 1969], No. 32001/69. Heading B5L. In a reciprocating saw comprising a plurality of saw blades 48, Fig. 2, mounted side-by-side and substantially upright in a frame 43 which is adapted for up and down reciprocation, means are provided to cause the frame to recede in the timber feed direction in the return stroke of each reciprocation and to advance contrary to said feed direction in the cutting stroke of each reciprocation, the locus of any point on the frame during the reciprocation approximating to an ellipse. As described the frame 43 comprises vertical bars 44 which are journalled on enlarged eccentric portions 35, 38 of crosshead shafts 29, 28 respectively journalled in vertical bars 23 of a carriage 22. A connecting rod 32 has one end 33 driven by an eccentric and its other end 34 is fixed to the portion 35 of shaft 29. Movement of the rod 32 causes the carriage 22 to slide up and down on rods 20 supported on a framework 10, so as to reciprocate the saw frame 43 vertically, and simultaneously causes the shaft 29 and the shaft 28 which is linked thereto to oscillate so that the enlarged portions 35, 38 cause the saw frame to reciprocate horizontally in correlation with the vertical reciprocation. Each saw blade 48 has one end secured to a spindle 49 and its other end apertured to receive an eccentric boss of a disc 51 which enables the blade to be individually tensioned. The discs 51 are mounted on a spindle 50 carried by a frame 54 movable by bolts 59 to tension the blades as a unit.