Patent GB-918916-A (GB)
Title: Improvements in or relating to the raising or lowering of buildings or machine beds or other structures
Inventor: PRYKE JOHN FORDHAM SPEAIGHT
IPC: E04G23/04
Filed: 1958-09-05
Abstract: 918,916. Machinery mountings. PYNFORD Ltd. Aug. 31, 1959 [Sept. 5, 1958], No. 28574/58. Class 80 (4). [Also in Groups X and XXX] In order that a structure such as a building or machine bed may be raised or lowered or tilted (e.g. to compensate for subsidence) relatively to its foundation by means of a small number of manual or power-operated jacks or screw devices, a substantial part of the weight of the structure is temporarily taken by supplying compressed air or other fluid to a sealed space extending beneath the major portion of the undersurface of the structure. After moving the structure, its weight is preferably transferred to permanent supports. As shown, a machine bed comprises a reinforced concrete raft A, Figs..1, 3, carried by integral peripheral beams A<SP>1</SP> engaging a footing or footing strips or pads C. The raft A is surrounded by a trench B and sealing means, such as the element D<SP>2</SP>, are provided between the beams A<SP>1</SP> and the trench side, or a wall B<SP>1</SP> in the trench. Compressed air is supplied to the space between raft A and its footings. Reinforcing beams such as A<SP>2</SP> have gaps A<SP>3</SP> to allow air circulation. Alternative sealing means may comprise a flexible strip fixed between the beams A<SP>1</SP> and the trench wall or simply packing in the trench. In a modification, Fig. 5 (not shown), the trench is deepened and sealing is effected by a head of water. The ground and, if desired, the trench wall may be covered by sealing material C<SP>1</SP>. For jacking purposes the beams A<SP>1</SP>, A<SP>2</SP> have pockets extending through to the footing and normally covered by plates F. Adjacent each pocket G, Fig. 8, are four embedded bolts G<SP>1</SP>. Jacks M are mounted over some of the pockets, abutment plates L<SP>1</SP> therefor being adjustably bolted to members L attached to the bolts G<SP>1</SP>, and distance pieces M<SP>2</SP> may be provided between the jacks and footing plates C<SP>3</SP>. Air seals N<SP>1</SP> are provided. Support pins H, Fig. 7, are inserted in the remaining pockets G<SP>1</SP> to engage plates J adjustably carried by extension bolts K attached to the bolts G<SP>1</SP>. Compressed air is then admitted to take most of the weight of the raft A, and while the jacks are operated the air pressure is maintained substantially constant and the nuts K<SP>2</SP> on the extension bolts K are continuously screwed down. After jacking the air pressure is released and the jacks removed so that the weight is taken by the pins H and the latter are then replaced one by one by permanent short pins abutting plates secured directly to the bolts G<SP>1</SP> (Fig. 9, not shown). Similar pins may be inserted in the jacking pockets. The cover-plates can then be replaced or alternatively the tops of the pockets may be filled with concrete. Finally, the trench may be covered after removing the sealing means therein. In modifications wherein the air pressure exceeds the weight of the structure, the footing is provided with bayonet, screwed or other sockets, Figs. 10, 11 (not shown), for receiving jacks or screw devices which oppose the lift of the air pressure. If the weight of the mach ine bed is very unevenly distributed, the space beneath the raft A may be divided (e.g. by water seals) into two or more compartments, Fig. 12 (not shown), in which different fluid pressures may be maintained. In a modification, the space under the raft is sealed a little way in from its periphery so that permanent supports, such as pins or brickwork, may be inserted from a surrounding trench.