Patent GB-1232042-A (GB)
IPC: B23K37/053
Filed: 1968-07-10
Abstract: 1,232,042. Welding by fusion. H. H. JACOBSEN, [trading as HERMANN ROSORIOUS, INGENIEURBURO]. 10 July, 1968 [11 July, 1967; 17 May, 1968], No. 32888/68. Heading B3R. A clamping device for clamping, aligning and centring workpieces, e.g. pipes, comprises a body pivotally mounting a plurality of clamping units each having pairs of lever arms extending on opposite sides of the body and means for simultaneously moving the lever arms together for clamping a workpiece therebetween. In the embodiment of Figs. 1 and 2, the body 1 supports two clamping units A, B, each comprising two pairs of lever arms 2, 5 and 3, 4 extending on opposite sides of the body and movable towards and away from one another by rotation of a spindle 25 having a handle 29. All the lever arms have identical workpiece engaging parts so that workpieces may be accurately positioned relative to each other, and the workpiece engaging parts, which may be magnetic or provided with serrations, may be interchangeable with different sized parts. The lever arms of each pair 2, 5 and 3, 4 are spaced by bushes 19, 20 and 21, 23, the latter being pivoted to each lever arm and rotatable on and threadingly mounting the spindle 25 which has counter-threaded parts 25<SP>1</SP>, 25<SP>11</SP>. The lever arms of each clamping unit A, B are mounted on a pivot 10 (which can be common to both units A, B) such that the pair of arms 2, 5 are external of the pair of arms 3, 4. The body has a vertical slot 26 in which the spindle 25 rises as the pairs of lever arms move together. One pair of lever arms, e.g. 3, 4 (Fig. 2) may be adjusted independently of the other pair by means of the bush 23 which mounts a further bush 23<SP>1</SP> bounded by pressure spring 32 and having a pin 30 for engagement with one of a number of notches 31 in the bush 23. To adjust the pair 3, 4 they are lightly compressed towards the body 1 so that the pin 30 can be removed, the bush 23 is then screwed on the spindle thread 25<SP>11</SP> until the lever arms reach the desired position, and the pin 30 is then repositioned in a notch 31. The notch 31 corresponding to the normal position of the lever arms 3, 4 may be marked. Since the lever arms of each clamping unit A, B are independent of those of the other unit, pipes of different diameters can be clamped and aligned. In another embodiment (Figs. 3, 4, not shown), the body comprises two parts pivotally joined and provided with a protractor (37), whereby the clamping units A, B may be angularly offset. The pivotal mounting may also provide a degree of telescopic movement between the body parts, and the pivot axis may be transverse of the body parts or in the same plane as the body parts. Alternatively, two mutually perpendicular pivots or a ball joint may connect the body parts. In another embodiment (Figs. 5 to 7, not shown) the clamping units are mounted on a tubular body and all the lever arms of both units are simultaneously operated by a single spindle having counter-threaded parts each mounting a tapering member (42) which cooperates with tapering surfaces (56) of parts of the lever arm pair bushes to urge the opposed lever arms together or apart. Alternatively, gear-wheel or chain transmissions may be used. In another embodiment (Figs. 8, 9, not shown), the lever arms of each clamping unit are operable by an hydraulic piston-and-cylinder arrangement which may be supplied by fluid from a common pump. Alternatively, compressed air may be used.