A method for driving in or out of solve of brackets, or is composed of the bottom in the

摘要

1,114,711. Universal joints; vibrating mechanisms. J. C. ORKNEY. 21 May, 1965 [2 June, 1964], No. 22696/64. Headings F2U and F2X. [Also in Divisions B4 and E1] Apparatus for driving, or extracting, a pile 1, Fig. 6, by vibration thereof comprises a block 5 supporting a vibrator, or periodic force generator, 2 on tension springs 6 and carrying an hydraulic motor 7, Fig. 7, for rotating a pair of eccentrically-loaded cylinders 12, 13 within the generator through worm and worm-wheel gearing 8a, 9, 10 and couplings 17, said cylinders being supported by a fluid or hydrostatic bearing system (14, 15), Fig. 3 (not shown), within a block 11. The gearing aforesaid is such that in operation the cylinders are contra-rotating to minimize transverse vibrations. Each of the couplings 17 includes a block (18), Fig. 5 (not shown), which is slidingly lodged between two mutually-perpendicular pairs of jaws 19, 20 on the ends of the corresponding worm and cylinder, a fluid-bearing system comprising recesses or pockets (21) in the block (18) being provided to minimize conveyance of vibrations from the cylinder to the motor. The motor 7 and the fluid-bearing systems are supplied with pressurized oil by pumps (22, 26), Fig. 1 (not shown), which are coupled to an I.C. engine (29), the spent oil being returned to a sump (25) through a cooler (30). In operation, the frequency of the vibrations generated in the pile is one other than the natural frequency of the pile in combination with the apparatus and such that the amplitude at the lowermost end of the pile does not exceed one half of that which would occur at the natural frequency. The generator may be such that the periodic force is variable. The generator 2 may be modified such that vibration is effected by a pair of contra-rotating eccentric masses 37, Fig. 8, each mass being attached to a sleeve 35 that is rotatably mounted on a fixed stub-shaft 34, which is secured to the block 11, a block 31 being slidingly lodged between jaws 36 at one end of said sleeve and engaged by the jaws 19, Figs. 6 and 7. The apparatus may be modified to produce either transverse or torsional vibrations, and may be used to vibrate elastic elements other than piles, e.g. drills, mandrels and tubes, so as to drive them into, or extract them from, e.g. soils, rocks, minerals, concrete, masonry and roads. An article such as an instrument can be vibration-tested while it is mounted on a bar that is subjected to vibration by apparatus similar to that aforesaid.