Patent GB-672784-A (GB)
Title: Improved means for raising girders and the like
IPC: E21D11/40
Filed: 1949-03-22
Abstract: 672,784. Load-handling apparatus; safety catch gear; load-engaging means. CORNER, F. March 22, 1950. [March 22, 1949] No. 7813/49. Classes 78 (iii) and 78 (iv). [Also in Group X] Means for raising girders and the like comprises a pillar fitted with chain or rope gearing whereby a bracket or platform slidably mounted on the pillar can be raised or lowered, said bracket being provided with means for gripping a girder or the like disposed across it or a girder-raising attachment resting on it, said gripping means being automatically engaged with and disengaged from said girder or the like by means operated by the chain or rope gearing when this is actuated to raise and lower the bracket or platform respectively. Fig. 1 shows the application in a mine wherein a pillar a adapted to be fixed between the floor and roof of a gallery comprises a telescopic extension tube a<SP>6</SP> for enabling the height of the pillar to be approximately fixed, the tube and pillar being adjustably connected by a pin passed through a hole in the pillar and one of a series of holes in the tube. A nut in the lower end of the tube is engaged by a screw a<SP>1</SP> which rests in a bearing a<SP>3</SP> on a foot plate a<SP>4</SP> and is rotated by a handle a<SP>2</SP> to adjust the final height of the pillar. A bracket c has a sleeve c<SP>1</SP> embracing the pillar, a platform c<SP>2</SP> supporting the girder d to be raised, and pairs of clamps kl, k<SP>2</SP> adapted to be moved into and out of engagement with the girder. The clamps k<SP>1</SP> are fixed on a pivot m<SP>1</SP> which is coupled by arms m' to a point m<SP>3</SP> free to oscillate within the bracket, and the clamps k<SP>2</SP> are fixed on a pivot m<SP>4</SP> coupled by an arm m<SP>5</SP> to the pivot m<SP>3</SP>. The arm m<SP>5</SP> is pivotally connected at h<SP>1</SP> to an endless chain h passing round chain wheels b, f supported on the pillar. When the girder has been placed on the platform c<SP>2</SP>, the chain h is driven by rotating a handle g<SP>2</SP> on a spindle g<SP>1</SP> carrying a pinion g meshing with a gear wheel f<SP>2</SP> integral with the chain wheel f. The initial upward movement of the chain, acting through the arm m<SP>5</SP>, moves down the pivot m<SP>3</SP> to cause the clamps to grip the girder flanges. On continuing the chain drive, the bracket and girder are raised and when the latter reaches the required height, it is fixed in position to support the roof, the bracket c being thereby relieved of the weight of the girder. On reversing the drive, the initial downward movement of the chain, acting through the arm m<SP>5</SP>, raises the pivot m<SP>3</SP> and causes the clamps k<SP>1</SP>, k<SP>2</SP> to open and disengage the girder flanges. The bracket can then be lowered for further use. The bracket c is provided with a safety device comprising a strap n pivoted on a lug n<SP>1</SP> and normally supported by a stirrup o integral with a pin o<SP>1</SP> upheld by a spring o<SP>2</SP>. Integral with the stirrup o is a tapered wedge p, the inner face of which is shaped to fit the pillar a. The wedge is received in a housing p<SP>1</SP> depending from the lug n<SP>1</SP> and tapered internally to suit the wedge. Should the chain break, the initial downward movement of the bracket c causes the housing to jam the wedge against the pillar and prevent further fall of the bracket. When the bracket is lowered in the normal manner, the initial downward movement of the chain h causes a pin on the chain to depress the strap n and the stirrup o so as to maintain the wedge clear of the pillar. Figs. 3, 4, 6, 7 show an arrangement for raising an arch girder comprising parts r<SP>1</SP>, r<SP>2</SP>. These parts are laid across a frame s resting on the bracket c with their lower ends resting on the floor of the mine and their upper parts received between pairs of guides t<SP>3</SP>, t<SP>4</SP> on arms t<SP>1</SP>, t<SP>2</SP> hinged to the frame s at s<SP>1</SP>, s<SP>2</SP>. On the bracket being raised by driving the chain h, flanges s<SP>3</SP> on the frame are gripped by the clamps k<SP>1</SP>, k<SP>2</SP>, Fig. 1, which are suitably elongated, and, with the lower ends of the girders remaining more or less stationary, 'the upper parts slide on rollers v<SP>1</SP>, v<SP>2</SP>. When the bracket has almost reached the top of the pillar a, the upper ends of the girders are brought into alignment by adjusting the arms t<SP>1</SP>, t<SP>2</SP> on their hinges s<SP>1</SP>, s<SP>2</SP> and the abutting ends of the girders bolted to fish plates. The completed girder is pressed hard against the roof of the mine whilst still on the bracket c by continuing the drive of the chain h, and chocks v then driven between the lower ends of the girders r<SP>1</SP>, r2 and the mine floor to secure the arch in position.