Patent GB-200723-A (GB)
Title: Improvements in machines for forming sheet metal pipe elbows
IPC: B21D9/14
Filed: 1922-08-08
Abstract: 200,723. Dean, W. Aug. 8, 1922. Corrugating; dies. - A machine for making sheet metal pipe-elbows automatically by an internal male die co-operating with external female dies so as to form a series of external bulges on the inner side of the bend and then squeeze them to produce outwardly-projecting ribs is constructed so that the pipe is arranged in a horizontal position during the bending operation. A cap d, Fig. 11, of U-section is fitted on the front end.of a lap-jointed pipe A, and the rear end secured by a clamp c<2> adjustable by a screw-operated lever c<4>, in a groove c' in a collar c, which is traversed step-by-step on a fixed hollow mandrel b. The mandrel is supported at its rear end in a fixed bracket and at its front end by a bent bar b<2> through a rod c<5>, carried by the collar and passing through a guide c‹ on the mandrel. The front end of the mandrel carries the rib-forming die i, which consists of a number of replaceable sections, radially moved outwards by a cam i' on a shaft i' passing through the mandrel and rotated by an arm i' connected by a link i<8> to a lever i<7>, which is raised by cams on a shaft f, rotated by gearing f<3>, f<4> from the shaft g. The die-sections are forced back by the movement of the pipe. The die i co-operates with a pair of holding and pressing dies e, which are carried by holders j, j<1>, hinged together transversely at j<2> and each of which consists of two halves pivoted at e<1>, Fig. 10, and provided with a series of replaceable radial die-sections. The die-holders are closed by a pair of cams e<6> on the shaft f, engaging bell-crank levers e<5> on the shafts e<3>, which are provided with levers e<2> connected by links e<9> to the die-holders. They are opened by cams e<7> assisted by springs e<8>. After the rib is partly formed by the die i, the dies e are closed and the pipe fed forward, whereupon the die holder j' is pulled towards the die holder j by rods j<3> connected to levers j<4> and operated by cams j<5> on a shaft j<6>, which is rotated by bevel gear j<8>, j<9> from the shaft g, so as to squeeze and thus complete the partially formed rib just before a second rib is started by the die i. The mandrel has a part i<9> loose on the shaft i<4>, which is normally pressed by a spring i<11> against a stop i<10>, but which is forced forward during the squeezing operation. The pipe is fed by a rack k carried by the collar which is engaged by a pawl k<1> carried by a frame l<1>, Fig. 5, which is rocked by a cam l on the shaft j<6>. The shaft g is connected to the driving shaft h by a dog clutch, the movable part h<2> of which is put into engagement by a hand lever h<4> through a link h<7>, connected thereto through a slot t, a sliding bar h<6> and a lever h<5>. When the desired angle of the pipe is obtained, a stop m on the rack k engages a lug n, so as to push forward a link o connected at its other end to a sliding bar p provided with a cam surface q, which thus raises a hooked lever r', pivoted on the bar h<6>, into the path of a pin s on a disk s<1> on the shaft j<6>. When the operation is completed the pin s retracts the lever h<5> and thus disengages the clutch. A rod k' connected to the lever h<5> is at the same time operated so as, through an arm k' to lift a cam k<2> and so to raise the pawl k<1> out of contact with the rack and so allow the collar to be moved back into its initial position against adjustable stops u on the rods j<3>, after unolamping the pipe.