Patent GB-848391-A (GB)
Title: Improvements in or relating to bending machines for tubes, í¡í¡ and like material
IPC: B21D7/024
Filed: 1959-02-24
Abstract: 848,391. Angular bending. BACK, H. Feb. 24, 1959 [Jan. 27, 1958], No. 6395/59 Class 83 (4). A machine for bending tubes or rods comprises at least one pair of spaced pivotably mounted bending heads each of which is pivotally connected as regards its free end by means of a thrust arm to a cross-head adapted to be reciprocated by power means, and a power actuated clamp mounted between said bending heads, the arrangement being such that when a tube or rod is inserted between two spaced abutments provided on each bending head and firmly held by the clamp the cross-head is forced towards the bending heads which are thereby caused to rotate about their pivot axes and thereby simultaneously to bend said tube or rod at two regions to predetermined angles. Two bending heads each comprise a flat plate 2 pivotable, about the axis of a grooved roller 11 mounted thereon, on a frame member 3 and also carrying a pressure roller 10. With the flat plates 2 in a position parallel to one another, a tube 13 to be bent is inserted between each roller 11 and a grooved pressure block 12 backed by the roller 10 and is positioned lengthwise by a stop 66. A clamp on the frame 3 between the two bending heads is then closed on to the tube, a roller 25, Fig. 3, on a compressed air actuated piston rod 26 swinging a grooved clamp part 21 about its pivot 23 to register with a fixed groove clamp part 20. A cross-head 6 connected by links 7 to the flat plates 2 is then moved towards the heads by compressed air cylinder means 4 to swing the plates 2 outwardly about their pivots, until stopped by adjustable studs 8, to bend the tube into a generally U shape. The blocks 12 are then removed and the bent tube extracted or a cut out portion 14 of at least one of the rollers 11 is turned to face the bent limb and the tube then removed, or at least one roller 11 may be split along a plane perpendicular to its axis, the outer half slipped off its pivot. A slotted connection 15 between a link 7 and a plate 2 allows the limbs of the tube to be bent different amounts, or the cross-head may be constructed as a lever. The plates 2 are adjustable along the frame 3 and the links 7 along the crosshead 6. That part of the tube between the bending heads may be bent by the clamp or by an extension on the cross-head 6 contacting the tube or the clamp. In a modification, Fig. 5, the links 7a are adjustable in length and each plate 2 supports a roller 11 or 11a and, adjustable in a slot 39, a pressure block 40 formed with a straight grooved part 41, which may be removable, to engage the tube. The block 40 may be swung to an operative or inoperative position by a handle 44 or a piston rod 46 of cylinder 47. The swingable part 52, Fig. 6, of the clamp is closed on the tube by a head part 56 pivoted on the piston rod 26 and engaging at its rear end a bracket 62. The machine may be operated by mechanical, hydraulic or electrical means instead of by compressed air. The cylinders 4 and 47 may be controlled by a pedal 71 and the clamp by a hand controlled valve 72 (not shown). A mandrel 74, Fig. 10, removably secured to a bracket 71 on an extension 70 of the plate 2 may support the tube internally.