GB777622A - A circular saw for cutting the jointing faces of segments of circular patterns - Google Patents

Abstract

777,622. Sawing; mitering; tools for setting out work. YVZKUMNY USTAV TVARECICH STROJU A TECHNOLOGIE TVARENI. Jan. 5, 1955, No. 344/55. Classes 61 and 145 A jig for positioning annular segments of a circular pattern in a sawing machine so that their ends can be trimmed to the required angle and chord dimension comprises an arm 18 pivoted at 17 in the plane of the saw 15 and a bar 21 which is supported by the arm and carries a pair of adjustable supports 23, 24 for engaging the outer arc of a segment and an adjustable depressible abutment 32 for engaging one end of the segment. To set the jig, the arm 17 is rotated until the front wall of the bar 21 registers with the required number on a scale 20 graduated with numbers corresponding to the circular pitch or number of segments required for a full circle and is locked in position by a clamp screw 22 fitting in an arcuate groove in an extension of the bar. The support 23, which is carried by a bar 26 adjustable along the bar 21 by a screw 25, is then set so that a pointer 27 coincides with the required number on a circular pitch scale 27<SP>1</SP> and the support 24, which is carried by a slide 28 clamped in position on the rod 21 by a screw 35, is displaced until a vernier 34 indicates the required calculated chord length L on an inch or millimetre scale on the bar 26. Finally, by rotating a screw 31, the depressible abutment 32 is adjusted on the slide to a position in which a pointer 33 coincides with the required number on a circular pitch scale 33<SP>1</SP>. A blank which is oversize chordwise is then placed against the supports 23, 24 so that there is enough overlap at one end for the saw to cut a clean surface and so that the abutment 32 is depressed by the other end of the segment. While the segment is held in place by a clamp 36, the saw 15, which is slidable on an arm 12 vertically adjustable on a column 8, is moved along the arm 12 by hand to make the first cut, the direction of rotation of the saw holding the segment down on the table. The saw is then returned to its initial position, the segment is reversed so that its cut surface bears against the abutment 32 and the other end of the segment is cut to give the required chordwise dimension of the segment.