US 3722600 A
Description (OCR text may contain errors)
United States Patent :19]
Hirata et al.
 METHOD FOR DRIVING PILES AND LIKE ELEMENTS INTO THE GROUND  Inventors: IIiroshi Hirata, Tokyo; Hiroshi Toyoda, Shizuoka, both of Japan  Assignee: Asahi Giken Kabushiki Tokyo,Japan  Filed: May 28, 1971  Appl. No.: 147,802
 US. Cl. ..l73/l, 61/535, l73/52, 175/49  Int. Cl. ..E02d 7/02  Field of Search ..173/1, 49, 52; 175/19; 61/535 [5 6] References Cited UNITED STATES PATENTS 3,100,382 8/1963 Muller ..6l/53.5
l l Mar. 27, 1973 Bodine 175/19 Bodine ..l73/52 X Primary ExaminerErnest R. Purser Attorneyl(elman and Berman 57 ABSTRACT Several piles or like elongated elements are driven into the ground simultaneously by a vibrator carried by a platform which is clamped to the several piles. The piles are themselves outside the path of the vibrator. The platform is shifted along the piles from time to time whereby piles of any length may be driven into the ground by an apparatus arranged closer to the ground than the upper ends of the piles in their initial positions.
2 Claims, 4 Drawing Figures PATENTEDHARZI 197s FIG.2
I N VENTOM. HIROSHI HIRATA HIROSHI TOYODA BY W AGENTS METHOD FOR DRIVING PILES AND LIKE ELEMENTS INTO THE GROUND This invention relates to a method of driving piles and like elongated elements into the ground, and to apparatus for performing the method.
It is common practice to drive a pile into the ground by means of a drop hammer or a vibrator acting on the upper end of the pile.
The known pile driving mechanism must be equipped with a frame of a height substantially greater than the length of the longest pile to be driven, or it is necessary to use shorter pile sections and to join them to each other at the side. Because of the size of the first mentioned type of equipment and because of the need for joining apparatus in the last-mentioned method, it has been costly and inconvenient heretofore to drive piles to great depths.
When a foundation is to be built on ground lacking adequate strength, piles are driven into the ground in large numbers in closely spaced relationship. The equipment and method commercially available heretofore made it necessary to embed each pile separately in the ground.
A primary object of the invention is the provision of a method of driving piles and like elements of any desired length by means of apparatus of limited height which may be much smaller than the length of the driven elements or element sections.
Another object is the provision of a method and apparatus for driving several such elements into the ground simultaneously.
With these and other objects in view, as will hereinafter become apparent, the invention, in one of its more specific aspects, provides apparatus including a carrier member, a guiding device for guiding the member in a vertical path, and an actuating drive which exerts repetitive pulses of downward pressure on the carrier member. The invention further provides means for fixedly and simultaneously fastening a plurality of piles or like elements to the carrier member in respective upright positions in which the elements are spacedly adjacent the path of the carrier member, while the carrier member is located in its path for joint downward movement with the elements under the pressure exerted by the actuating drive.
In operating such apparatus with very long piles, the carrier member is initially fastened to respective portions of the elements intermediate the longitudinal ends of the same. A downward force is exerted on the carrier member, as by a vibrator, while the secured elements are arranged on the ground in respective upright positions, the force being exerted until the lower longitudinal ends of the elements are embedded in the ground.
The carrier member is then released and shifted on each element in a direction away from the embedded end, whereupon the carrier member is again fixed to each element in the shifted position. Downward force is again exerted on the carrier member until an additional portion of each element is embedded in the ground. The procedure is repeated until the elements are driven simultaneously to the desired depth.
Other features, additional objects and many of the attendant advantages of this invention will be appreciated readily as the invention becomes better understood from the following detailed description of a preferred embodiment when considered in connection with the appended drawing in which:
FIG. 1 shows a pile driving apparatus of the invention in side elevation;
FIG. 2 shows the apparatus of FIG. 1 at a later stage of operation;
FIG.-3 shows the apparatus of FIG. 2 in enlarged section on the line IlIIII and partly in phantom view; and
FIG. 4 illustrates a portion of the device of FIG. 3 in a perspective view.
Referring initially to FIG. 1, there is seen a flatcar 1 arranged for movement on temporary rails 2 over a construction site whose soil is to be strengthened by piles. A horizontal guide and positioning plate 3 releasably mounted on the car 1 is provided with openings (not shown) in a square pattern, and an upright tubular stake or pile 4 is received in each opening. The bottom end of each pile 4 may be provided with a conical point to facilitate penetration of the soil by the pile.
Near their longitudinal centers, the piles 4 are fixedly connected by a platform 5 which will presently be described in more detail. A column 6 stands on the flatcar 1 near the guide plate 3 and supports two guide pulleys 7,8 at its upper end. A cable 9 is trained over the pulleys 7,8, and one end of the cable is attached to a vibrator of which only the casing 10 is seen in the drawing. The platform 5 serves as a carrier for the casing 10 and is fixedly attached to the casing by welding or otherwise.
The other end of the cable 9 is attached to a winch 11 mounted on the flatcar 1 and driven by an engine 12 through a transmission 13 which may engage or disengage the winch and engine, or may reverse the direction of rotation of the winch l 1 when operated by a control lever 14.
The internal elements of the vibrator, obscured in the drawing by the casing 10, but known in themselves,
include several heavy masses eccentrically joumaled in the casing 10 for rotation about respective horizontal axes, and an electric motor, drivingly connected to the eccentric masses and electrically connected to an externalvpower supply by a flexible cable, not shown. As the motor rotates the eccentric masses in proper synchronization, repetitive pulses of downward force are exerted on the vibrator casing 10, the platform 5, and the piles 4 attached to the platform so that the pointed lower ends of the piles enter the ground, and the lower end portions of the piles are embedded in the soil. Upward movement of the centers of a gravity of the several eccentric masses does not exert a corresponding upward force on the piles 4 because of the opposing gravitational forces which enhance the downward driving efi'ect.
When the platform 5 approaches the guide plate 3, the vibrator in the casing 10 is stopped, the platform 5 is released from the central portions of the piles 4, shifted upwardly away from the embedded ends of the piles, and again fixedly fastened to the piles, whereupon the vibrator 10 is started again, and the driving operation is resumed. When the piles 4 are almost completely embedded in the ground, the condition illustrated in FIG. 2 is reached in which the platform 5 is fastened to the upper ends of the piles 4, while the central portions to which the platform 5 was initially attached are deeply embedded in the ground.
Before the platform 5 is shifted to the final position shown in FIG. 2, the guide plate 3, which is no longer needed, is removed, and the vibrator lowers the platform with the attached piles until the platform and the tip ends of the piles 4 are driven almost to the tracks 2, and are cleared by the flatcar 1. The platfom-i is then lifted from the embedded piles by the winch 11, and the car 1 may be moved to a new position in which another group of four piles may be driven into the ground simultaneously as described above.
As is better seen in FIGS. 3 and 4, the platform 5 consists essentially of a heavy, square metal frame 15 which carries the vibrator casing shown in FIG. 3 in phantom view, and omitted entirely from FIG. 4 for the sake of clarity. The frame is guided in a vertical path by means of brackets 16 movably engaged in guide channels 17 which extend over the full length of the column 6. Short diagonal projections 18 in the four inner comers of the frame 15 have corrugated, cylindrically concave clamping faces 19. A hydraulic motor having a cross-shaped cylinder 20 is mounted on the casing 10 in a conventional manner, now shown, in a common horizontal plane with the frame 15. Clamping blocks 21 are attached on the outer ends of four piston rods 22 which project from the cylinder 20 at right angles to each other. Hydraulic pressure in the cylinder 20 holds the piles 4 clamped between the faces 19 and cooperating analogous faces of respective blocks 21 in the condition of FIG. 3. v
The cylinder 20 and the frame may be moved vertically in spacedly adjacent relationship to the piles 4 by the winch 11 acting on the vibrator casing 10 which itself moves in a vertical path horizontally offset from each pile, the initial positions of the piles 4 being defined by the positioningplate 3.
The flexible pressure hoses which depend from the motor 20, the associated pump driven by the engine 12, and the control valves which connect the hoses to the pump and to an oil pump have not been shown since they are entirely conventional in hydraulic equipment of the general type illustrated. The valves may be shifted by the operator to move the clamping blocks 21 toward and away from the clamping faces 19.
The cable 9 holds the vibrator 10 in the position seen in FIGS. 1 and 2 in which the vibrator can be moved freely between the two pairs of piles 4 together with the frame 15 which also clears the piles when the latter are not clamped to the platform 5.
As is evident from FIG. 1, the length of the unitary piles which may be driven by the apparatus of the invention in the afore-described manner is independent of the length of the column 6 which is the tallest member of the pile driving apparatus. If the pile length is limited by available transportation equipment and the like, the apparatus illustrated may be employed for driving piles assembled on the working site from individual longitudinal sections, as by bolting or welding, but it is not limited to the use of such multi-section piles if the driving depth exceeds the height of the column 6. The pile driving apparatus has a low center of gravity, and is therefore stable and safe.
While the invention has been described with reference to piles permanently embedded in the ground for strengthening the same, the apparatus and the method described above are not limited to the driving of such piles, but may be employed, for example, for
drivin tubular casings or the like into the ground. Such em ded casings may be used for forming columns of compressed sand or other material, and may be withdrawn after serving this purpose, leaving behind areinforcing column of sand etc.
Hydraulic clamping devices are preferred for fastening the platform 5 to the several piles or other elongated soil reinforcing elements, but other devices may be employed to transmit downward forces from the platform frame 15 to the elements. The use of heavy horizontal pins passing through aligned openings in the frame 15 and the piles 4 is specifically contemplated.
Other modifications and variations of the present invention are abviously possible in the light of the above teachings. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically disclosed.
What is claimed is:
1. A method of simultaneously driving a plurality of elongated elements into the ground which comprises:
a. fixedly securing a carrier member to respective portions of said elements intermediate the longitudinal ends of the latter;
b. exerting a downward force on said member while the secured elements are arranged on said ground in respective upright positions, said force being exerted until the lower longitudinal ends of said elements are embedded in said ground;
0. releasing said member from the partly embedded elements;
shifting said member on each element in a direction away from the embedded end;
e. fixedly securing said member to each element in the shifted position; and
f. again exerting a downward force on said member until an additional portion of each element is embedded in said ground.
2. A method as set forth in claiml, wherein said additional portion is said intermediate portion.