Improvements in or relating to devices for the driving or extraction of piles

摘要

937,360. Pile driving. SOC. CIVILE PROCEDES D.B., and SOC. DES CHANTIERS REUNIS LOIRE NORMANDIE. Nov. 28, 1961 [Dec. 9, 1960], No. 42543/61. Class 68 (2). A device for driving or extracting piles comprising in a frame 10 rigidly fixed to the pile 12 and without external support, a generator 14 of alternating impulses giving unidirectional percussions to elastic members such as springs 19 interposed between the frame and the generator, is provided with means for counteracting, reducing or annulling the effect of the forces directed in the sense opposite to the unidirectional working percussions. In the embodiment of Fig. 2 said means consist of springs 22 arranged between the impulse generator 14 and the frame 10. In the stopped position shown there is a space 23 between the hammer 17 and the anvil 18. The generator has flywheels 15 with eccentric weights 16, rotating in opposite directions and synchronized. In Fig. 4, the impulse generator comprises two sets of superposed flywheels 24, 25 with eccentric weights 26, 27, and transmission 36, one set (24) rotating faster than the other (25), so that a more powerful action is obtained in the downward direction than in the upward. In Fig. 6, the frame 10 has therein eccentrically weighted flywheels 28 coupled by a sliding transmission 30 to the eccentrically weighted flywheels 15 of the moving generator 14, the flywheels 28 increasing the percussion effect of the generator 14 but annulling it in the opposite direction. In Fig. 7 the generator 14 sliding in the frame 10 carries a frame 31 in which slides a further impulse generator 32 with eccentrically weighted flywheels 33 connected to the flywheels 15 by a sliding transmission 35. The springs 19 and 22 are placed on opposite sides of the generator 32. In all the above embodiments an elastic shock-absorbing element may be arranged between the impulse generator and the hammer. Specifications 780,380 and 839,921 are referred to.