GB190505608A - - Google Patents

Abstract

5608. Shires, J., and Wooller, J. M. March 17. Tenoning etc.; tools; sawing. - A machine for dovetailing floor joists and the like consists of a saw frame E dependent from and supported by a carriage D, reciprocating on slides C, attached to a framework B on a table A, the frame carrying, at a suitable angle to each other, two saws F, one of which may be adjusted towards the other, through slots Y and bolts Z, for varying the width of the dovetail socket. Each saw has a convex cutting-edge and has a very short traverse, about three inches, the centre of the saw coming in contact first and gradually extending the cut. The carriage D is reciprocated by a connecting-rod G, driven by a crank-shaft carrying a pinion K, which gears with a second pinion L operated by a hand-wheel M or by a motor. The timber to be operated on is fixed on the table between the framework B and a clamp P, operated by a screw R. The saws, which rest on the timber by their own weight, may be raised by a hand-lever T, pivoted at U and connected to a bar N attached to the saw frame, which itself moves in dovetail guides V in the carriage D, and is held in its raised position by a pin W passing through the bar N. For trimming the dovetail socket or pin, a chisel 3 is fixed to a tool-holder 2, connected by a pin, sliding in a slot in the stand, to a link which is attached to a weighted lever for reciprocating the tool. The timber is held down by a clamp 9, mounted on a lever 11 pivoted to the stand 12. To form the piu of the dovetail, the chisel is replaced by a saw having two obliquely disposed blades, fixed to a frame and having a plate for stiffening the frame and adjusting the position of the joist.