GB801809A - An improved apparatus and method for flame-cutting metal joists and the like - Google Patents

Abstract

801,809. Cutting by fusion. MARRIAGE, F. H., and PENFOLD, R. L. Jan. 4, 1957 [Nov. 9, 1955], No. 32073/55. Class 83 (4). Apparatus for flame cutting a metal joist 1 or the like, transversely of its length whilst it is supported horizontally, comprises a frame 3, 4, 5 adapted to straddle the joist and to be locked thereto and carrying a web-cutting burner 38 mounted for horital movement and two flangecutting burners 43 mounted for vertical movement, the three burners being driven by a motor 11. The frame has a depending limb 4 rigid with its horizontal cross-member 3, and a depending limb 5 adjustable along the cross-member by a handle 51 to suit different joists. Rollers 6 ride on the joist flanges 7 whereby the apparatus may be moved along the joist and then clamped thereto by turning the handle 51, when in the cutting position. Motor 11 actuates a lead screw 26 driving a horizontally slidable member 35, carrying the burner 38 and through bevel gearing 13, 14, 18, 22, two vertical shafts 15, 23 with lead screws 49 driving the flangecutting burners 43. The height of burner 38 is adjustable by handle 37 and the burner may be swung upwards out of the cutting plane, Fig. 3 (not shown), and retained by a catch. In operation the flange-cutting burners are positioned at their bottom position and then ignited. The motor is started to move these burners upwardly to cut the flanges whilst the unignited burner 38 having been moved out of the cutting plane travels across.the web. When burners 43 reach their upper positions they run off their lead screws and are then extinguished. Burner 38 continues to move across the web at an increased speed and may be ignited and returned to the cutting plane so as to pre-heat the web during this movement. The motor is then reversed and moves the burner 38 at its cutting speed in the opposite direction across the web to complete the cutting of the joist; simultaneously the burners 43 move vertically downwards to their starting positions where they disengage from their lead screws but remain pressed against the ends 48 by springs 47.