US3009522A - Pile-driver with a hydraulically operated pile rammer - Google Patents

Description

Nov. 21, 1961 w BEDNER 3,009,522

PILE-DRIVER WITH A HYDRAULICALLY OPERATED PILE RAMMER Filed March 24, 1958 2 Sheets-Sheet 1 INVENTOR ju/us Wilhelm Bed/ier SYM CSW xwm ATTORNEY.

Nov. 21, 1961 J. w. BEDNER 3,009,522

PILE-DRIVER WITH A HYDRAULICALLY OPERATED PILE RAMMER Filed March 24, 1958 2 Sheets-Sheet 2 INV ENTOR 7&4 ATTORNEYS United States Patent 3,009,522 PILE-DRIVER WITH A HYDRAULICALLY OPERA'IED PILE RAB/[MER Julius W. Bedner, 287 Marco Polostraat, Amsterdam, Netherlands Filed Mar. 24, 1958, Ser. No. 723,475 Claims priority, application Netherlands Mar. 27, 1957 2 Claims. (Cl. 175-152) The invention relates to a pile-driver `with a hydraulically operated pile rammer. It is known to have such rammers operate in such a way that to the side of the pile-driving frame on the ground a liquid tank with a pumping and control device is placed, from which a hose passes to the pile rammer, through which hose the liquid is able to ilow to the rammer. The hose is subject to violent shocks and to swishing movements, in consequence of which it has a relatively short life, while the liquid pressure is greatly limited because the hose can resist only a limited pressure. Great losses of energy occur in the hydraulic system because every now and then a large quantity of liquid has to be accelerated and retarded with great length of the tubing and accordingly with great friction losses.

The invention aims at providing an improvement in this respect, and to this end a hydraulic pile-driver according to the invention is characterized in that a liquid tank, a pumping apparatus, and a control device for the flow of the liquid are combined with the piping system for supplyin the hydraulic medium to the cylinder chamber of the rammer and thence back to the tank, so as to form one unit, adapted to be suspended in a pile-driving frame. No long and swishing tubes and the like are then required and the hydraulic pressure can be chosen to be very high, in consequence of which the volume o-f liquid to be displaced can be small at a given weight of the pile rammer, so that the pumping energy as well as the size of the rammer at a given weight can be smaller.

The said composite unit is preferably connected with the piston rod the piston of which operates in the cylinder chamber of the rammer and which may or may not be supported on the pile to be driven.

The invention further relates to a few features which are to be preferred in order to put the main idea of the invention into practice in an advantageous manner.

The invention is now to be elucidated further with reference to the annexed drawing. In the latter:

FIGURE l is a side-elevation, partly broken away, of a pile-driver according to the invention;

FIGURE 2 is an elevation and vertical section of this pile-driver at right angles to the plane of the drawing of FIGURE l;

FIGURE 3 is a cross-section in three different places of a control valve used in the pile-driver of FIGURES 1 and 2; and

FIGS. 4 and 5 are fragmentary views, on an enlarged scale, of the hydraulic fluid control device of the invention illustrated in FIG. 2, showing the extreme left-hand and right-hand positions of the chain wheel S6.

A pile rammer 1 on the inside has a central cylinder chamber 2 and is guided to perform a reciprocating motion along vertical arms 3 of a framework by means of arms 4 with eyes 5 at the upper end of the rammer and by an eye 6 on arms 7, rigidly fitted at the lower end of the arm-s 3.

The vertical arms 3 are interconnected at the upper end of the apparatus by a bridge member 8, yformed by two plates at some distance from each other, between which a suspension eye 9 engages with its shank, which shank at the `bottom carries a spring-disc 10. The latter rests against a spring 11, which at the top rests against a cross- ICC beam 12, rigidly ltted between the plates of the bridge member 8.

Further towards the lower end of the vertical arms 3 a bridge member 13 is firmly clamped around them and in the centre carries a piston rod 14, which has a broadened portion 15, embodied as a piston movable with a sliding tit in the cylinder chamber 2 of the pile rammer and which, if desired, may carry on its surface suitable sealing members, such as packing rings, piston rings or sealing collars. In the downward direction the piston rod 14 merges into a thinner portion 16, which beneath the cylinder chamber 2 in the rammer passes with some clearance through a bore 17, in consequence of which this piston rod can rest with its free lower end on the pile to be driven. i

The piston rod 14 has a bore 18, which at the top passes through the end-surface of the piston rod and which ends downwardly at a short distance above the piston 15, where it merges into a number o-f radial bores 19, which end in the cylinder chamber 2 above said piston.

At the lower end of the cylinder chamber 2 a number of radial bores 20 have been made in the pile rammer in order to prevent air compressions in the cylinder chamber 2 beneath the piston 15.

In and above the bridge member 13 bushings 21 have been rigidly tted about the vertical arms 3 and at the upper end thereof helical springs 22 rest on said bushings. In the upper part of the apparatus between the arms 3 a sheet-metal casing 23 is arranged, which may have suitable reinforcing beams 24. `On the outside of said casing, on opposite sides, eyes 25 are present, which engage with a sliding tit about the arms 3 and the lowermost of which rest on the springs 22 and thus elastically support the sheet-metal casing with all its components on the framework. At the lower end said casing is open. At the upper end it is shut off by a casing 26. In said casing 26 there is a liquid tank 27 formed by parts of the side, lower, and upper walls of said casing 26 and by a partition 28. Near the bottom the tank has an opening 29 in the partition 2S, which leads to a rotary pump 30 for high pressure. This pump is driven via a coupling 31 by an electric motor 32, which is rigidly supported in the casing 23 and from which another driven shaft extends in the downward direction. The current is supplied to the motor from the ground by means of an electric cable 33. The shaft extending downwards `from the motor carries at the lower end a worm 34 meshing with a worm wheel 35, which drives a large toothed wheel 36 via a double reduction gearing. This toothed wheel 36 is provided with a number of holes 37 arranged in a spiral path and pivotally supports a connecting rod 38 on a pin, detachably fitted in one of said holes 37 in such a way that it is possible to engage at will connecting rod 38 in any of the holes 37 of the wheel 36 with a view to varying the stroke of this connecting rod.

At the upper end the connecting rod is pivotally connected with a lever 39, which is rotatable about a shaft 4i) of a control device for the hydraulic fluid. This shaft 40 carries a rotary valve 41, in which in Various points three continuous passages have been provided. From the pump 30 a duct 42 leads to a passage 43 in the valve with a branch Vduct 44 to a passage 45 in the valve. The passage 43 communicates with a duct 46, which leads to a T-joint 47. The passage 45 leads to the duct 48, which leads back in the upward direction to the tank 27. The T-joint 47 communicates witha duct 49, which leads to the bore 18 in the piston rod 14. Also connected to this T-joint is a duct 50, which leads to a passage 51 in the Valve 41, with whose other end is connected a duct 52, which al-so leads back to the tank Z7. In FIGURE 3 a cross-section is shown of the three passages 43, 45 and 51 in the valve, with their connections in the casing, in the position for lifting the rammer.

At the upper end the connecting rod 38 has a slot 53, with which it engages about a pivot pin at the end of the lever 39. At the end of each rotating movement of the control valve 41 there is thus a pause, determined by the number of strokes per unit of time of the connecting rod 38 and by the length of the slot 53.

The lever 39 is not rigidly connected to the shaft 4l), but via a bushing 54 mounted on the shaft 4). Normally this bushing engages with keys 55 upon the shaft 4t), so as to carry along the latter. A chain-wheel 56 is rotatable about the shaft 40 and at the right end (FIG. 2), has oblique guide surfaces on its hub. The latter have been made in such a way that in the two extreme positions of the chain-wheel 56 a certain locking is brought about, in consequence of which the chain-wheel 56 is kept in position in the adjusted angular position relative to the shaft 40. In the end position shown in the drawing the bushing 54 engages through the keys upon the shaft 40 so as to carry it along. When the chain-wheel S6 is turned, by means of a chain fitted around it and reaching to near the ground, the oblique guide surfaces on the hub of the chain-wheel S6 push the bushing 54 against the action of a spring 57 towards the valve 41, so that the bushing is no more coupled to the shaft 40 through the keys. It is then possible to turn the valve to and fro by hand by means of a chain slung round a chain-wheel 58 which is rigidly fitted on the shaft 4t), so that the desired rate of driving the piles can be applied by hand if this rate has to be different from that determined by the motor 32 and the automatic mechanism described. In FIGURE 4 the guide surfaces are so in contact that the bushing 54 is in the most left-hand position, in which the key 55 entrains the shaft 48 and thus rotates the rotating valve when the mechanism 38, 39 moves. When the chain-wheel 56 is moved over a certain angle, namely in this case-with four sets of guide surfaces-over an angle of 90, the situation arises which is shown in FIG- URE 5, wherein the bushing 54 is pushed to the right, so that key 55 in shaft 40 is no more present on a keyhole tting exactly around it, but is present in a circumferential groove in bushing 54, so that when the mechanism 38, 39 moves on to turn the bushing 54 to and fro the shaft 40-and, thus, the valve-will not follow this movement. The spring 57 urges the bushing S4 to the left and thus tends to restore the situation of FiG- URE 4.

The apparatus operates as follows:

From the ground electric current is supplied by the electric cable 33 to the motor 32. The latter thereby begins to rotate, drives the pump 30 and at the same time the connecting rod 38. The valve 41 is thus moved to and fr0. Suppose this valve to be in the position shown in FIGURES 2 and 3. The liquid forced away by the` pump from the tank 27 through the duct 42 then ilows through the passage 43 in the valve 41 and through the duct 46 to the T-joint 47, and thence through the duct 49 to the hollow piston rod 14 and through the bores 19 to the cylinder chamber above the piston 15 in the pile rammer. The rammer is thus raised, during which movement the extended piston rod 16 remains resting with its lower end on the pile. The lever 39 is then in the position shown in FIGURE 1. The connecting rod 38 moves until the lower end of the slot 53 comes into contact With the pivot pin on the lever 39. Upon this the valve is moved counterclockwise, seen in FIG- URES 1 and 3. The passage 45 will now begin to connect the ducts 44 and 48, and this connection is already established to some extent before the passage 43 has isolated the ducts 42 and 46 entirely from each other. Because the pump therefore can no longer force the liquid via the ducts 46 and 49 to the pile rammer, the liquid can circulate from the pump through the branch 44, the passage 45 and the duct 48, and thus back to the tank. Meanwhile the passage 51 is put into a position in which the ducts 52 and 5t) are thereby connected with each other. The liquid from the cylinder chamber in the pile rammer 1 can now flow back through the latter ducts. The rammer sinks by its own weight and thus forces the said liquid back into the tank, for which no appreciable difference of pressure is necessary. Meanwhile the pump continues to operate and the liquid circulates back through the duct 48 to the tank.

After some time, during which the connecting rod 38 has moved upwards and then down again and during which the valve was stationary, the connecting rod pulls the lever 39 back to the initial position shown in the drawing, so that the rammer is raised again.

The short ducts in the apparatus, which do not swish, can easily be constructed in such a way that they can resist high pressures. It is therefore possible to operate with high liquid pressures, so that the volume to be displaced can be small, in consequence of which the tank, the pump, and the cylinder chamber in the rammer can be small, which involves a great advantage with respect to the weight that has to be supported by the pile-driving frame and the size of the apparatus. The rammer itself will thus have favourable dimensions and the energy losses will be small.

What I claim is:

1. In a pile driving apparatus having a stationary frame, a vertical piston rod secured to said frame, said piston rod having a piston thereon, a pile rammer having a cylindrical chamber therein, said pile rammer being mounted upon said piston rod `for vertical movement relative thereto with said piston within said cylindrical chamber, and means for introducing hydraulic uid within said cylindrical chamber to move said rammer relative to said piston means; the improvement wherein said means for introducing hydraulic uid within said cylindrical chamber consists essentially of the hereinafter defined components forming a compact unit which unit in turn is secured and carried yby said frame, said components being: a liquid-containing tank, a uid pump having an inlet connected to said tank and an outlet, a rotary valve having three controllable passages therein, iirst conduit means providing communication between said pump outlet and said cylindrical chamber to move said rammer upwardly on said piston rod, one passage of said rotary valve being connected in series in said first conduit means, second conduit means providing communication between said cylindrical chamber and said liquid tank, a second passage of said rotary valve being connected in series in said second conduit means, third conduit means providing communication between said pump outlet and said liquid tank, a third passage of said rotary valve being connected in series with said third conduit means, and electric motor means driving said pump and rotating said valve to alternately close and open said first passage and to simultaneously open and close said second and third passages, said electric motor means including an electric motor having an output shaft, gearing means driven by said output shaft, and a crank connected at one end to one gear of said gearing means, said crank being also connected to said rotary valve to operate the same upon actuation of said electric motor, the connection of said crank to said rotary valve including slot and pin means periodically causing a pause in the positioning of the.

References Cited in the tile of this patent UNITED STATES PATENTS 2,068,045 Wohlmeyer Jan. 19, 1937 (Other references on following page) UNITED STATES PATENTS Salentine Mar, 16, 1937 Grant Aug. 16, 1938 Haage Aug. 30, 1938 Brimer Aug. 1, 1939 5 Alcorn Apr. 4, 1944 Shimer June 18, 1946 Grebe Aug. 5, 1952 Simmonds Mar. 25, 1958 FOREIGN PATENTS Great Britain Oct. 13, 1938

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