US3356164A - Pile driving mechanisms - Google Patents

Description

Dec. 5, 1967 w. w. MOUNT 3,356,164

PILE DRIVING MECHANISMS Filed June 7, 1965 2 Sheets-Sheet 1 1 NVE N TOR Wwswamw /1/. Mam/r BY Dec. 5, 1967 w. w. MOUNT 3,356,164

FILE DRIVING MECHANISMS Filed June 7, 1965 2 Sheets-Sheet 2 INVENTOR. MOS/WORTH h! Maw/r United States Pa 3,356,164 PILE DRIVING MECHANISMS Wadsworth W. Mount, Warren Township, Somerset County, NJ. (Mountain Ave., Plainfield, NJ. 07060) Filed June 7, 1965, Ser. No. 462,027 12 Claims. (Cl. 173-102) ABSTRACT OF THE DISCLOSURE A pile driving mechanism incorporating a lifting assembly between the base of a heavy hammer and the helmet mounted on the top of a core or pile to be driven. The lifting assembly includes a cylinder member and a piston sliding in the cylinder member. The top of the cylinder member bears against a cushion block which is struck by the ram point of the heavy hammer. A bottom surface of the cylinder contacts the top of the piston or the helmet directly, when the cylinder and piston are in closed position. A lower surface of the piston bears against the helmet. A chamber within the cylinder member exposed to a top surface of the piston contains a fluid which is applied under pressure to force the piston downwardly and the cylinder member upwardly, thereby raising the cylinder member and the entire structure thereabove, which includes the heavy hammer mechanism. The fluid pressure is dissipated to permit the cylinder member and structure to fall, thereby imparting a heavy blow to the helmet by virtue of the falling weight of the hammer assembly. Alternatively, a lifting mechanism of the type just described may be positioned in the bottom of a core that drives a pile shell and in which the cylinder member is positioned inside and is attached to the bottom of the core. Fluid pressure within the chamber raises the entire core and all that weight above the core to drop the core and such weight to drive the pile downwardly.

In pile driving for the foundation of buildings and the like, it is the established practice to advance the pile by dropping a heavy weight on its outer end until the pile reaches a formation in the earth where the usual drop hammer blow only advances thepile for a predetermined short distance, such as one-half inch. The architectural specifications are thus satisfied that the pile will provide adequate support.

Any device which acts below the surface so that the above factor cannot be determined is unsatisfactory.

It is well known that the pile will advance several feet with each hammer blow while loose sand or like formation is encountered, and one object of my invention is to retain the standard drop hammer mechanism but to supplement it with means for speeding up the advance of the pile through the soft formations.

This inventiondistinguishes from the prior art vibratory mechanisms which act to pull the pile up, as well as push it down, at each stroke of the vibrator, because I employ only a series of downward strokes comparable to a very large number of blows with a second hammer, which does not in any way interfere with the low-periodicity blows of the main driving hammer.

An object of the invention is to provide a means for continuing the pile in downward motion during the time interval between the blows of the ram of the main driving hammer.

An object is to provide a relatively high frequency v and short stroke hammer which may be interposed between the pile being driven and the main hammer and which may be operated at will without interfering with the regular operation of the main hammer.

Another object is to provide a means for creating downward hammer blows by the rapid lifting and dropping of the entire main hammer assembly or, alternately, by lifting and dropping the main hammer and core assembly, or just the core assembly, on the pile being driven.

Other objects and advantages will be apparent from the following detailed description and from the accompanying drawings.

FIG. 1 is an elevation of the pile driving mechanism of this invention with a small portion of the casing broken away to show the core and the casing joint of a stepped pile.

FIG. 2 is a sectional elevation, on a larger scale, taken on the line 2-2 of FIG. 1.

FIG. 3 is a sectional elevation of an alternative structure which also embodies this invention.

FIG. 4 is a partially sectional elevation of a high pressure hydraulic actuator which is adapted for lifting the weight of the primary hammer together with the entire core and is dependent on the usual steam or air pressure as the primary source of power.

Referring first to FIGS. 1 and 2, a casing or shell pile 10 having a bottom plate 11 is adapted to be forced into the ground by the usual internal core 12. The core extends substantially above the upper end of the casing, which is indicated at 13. A heavy helmet 14 is mounted on the top of the core 12 and is adapted to receive hammer blows so that the core and the casing are driven downward, as hereinafter explained.

A heavy weight hammer means (pile driving hammer) 15 is mounted on the top of the casing with a high periodicity hammer 18 interposed between the helmet 14 and the hammer base 20 through which the ram point 21 of the heavy hammer strikes. The ram point 21 is attached at the bottomof a heavy ram weight 22 which has holes 23 and 24 extending longitudinally of the hammer and through which guide rods 26 and 27 extend. These guide rods are affixed at the bottom to the hammer base 20 and at the top to cylinder 30 in which a piston 31 operates. Piston rod 32 extends downwardly through a close fitting opening in the bottom of the cylinder and is attached at its lower end to the heavy ram weight 22. The arrangement is such that when the piston is raised, the heavy weight 22 slides upwardly 0n the guide rods 26 and 27, and when the piston 31 is released at the top of its stroke, the entire mass of the weight 22, piston rod 32, together with the ram point 21, drops by gravity and the'ram asserts a very heavy blow on the cap block assembly resting on top of the crown plate 45, piston 47 and helmet 14. -A flexible hose 35 delivers compressed air or steam through valve 36. The valve has a rocker 37 actuated by keys 37a on slide bar 37b connected to the ram weight 22, and when the hammer weight and piston are at the bottom of the stroke, the valve is set to open position and the air or steam enters the cylinder through port 40, drives the piston in an upward direction, and lifts the weight to the upper end of its stroke. As soon as the piston passes eX- haust ports 41, the valve rocker is reversed by the ram key 37a which liberates the compressed air or steam out through the valve, some of which gushes out through these ports 41, thereby permitting the weight 22, piston rod 32 and the piston 31 to drop by gravity and assert a heavy blow from the ram onto the core head 14, through the cap block assembly and the high-periodicity hammer 18. The core 12, the core head or helmet 14, and the cylinder and piston of the high periodicity hammer 18 are held in loose-fitting alignment by means of steel cables 18a. q

The hammer base .20 has a conical central cavity 20b, as shown in FIG. 2. A frusto-conical member 20a, commonly called a cap block or cushion block shield, fits into the frusto-conical hole 20b in the hammer base, thus making the base and cap block self-adjusting and self 3 'centering. The member 20a has a cylindrical hole 20c provided with cylindrical disks'20a' and 20s with wood chips or other yielding packing 20 between them.

When the ram point 21 strikes disk 20d, the blow from the heavy hammer is somewhat softened by the packing 20) although the blow is delivered through disk 20a to the crown plate 45 and thence to helmet 14 and core 12.

As already explained, in driving piles in this manner the core 12 and the shell may advance several feet at eachblow of the hammer if the pile is being driven through comparatively soft sand or the like, but if the sand strata is deep, a considerable amount of time is consumed before the bottom plate 11 has passed through the sand structure and meets more solid strata, such as shale or the like. It may take hard pounding to go through the hard strata and again meet soft strata.

According to this invention, the operation of driving the pile through the soft sand or like formation is greatly speeded up by the introduction of a high-periodicity hammer interposed between the hammer base member 20 and the helmet 14, as clearly illustrated in FIG. 2, to which special reference will now be had.

While FIG. 2 is shown on a much larger scale than FIG. 1, the helmet 14 is designated by the same reference number, and the cushion block 20a has a cylindrical projection 42 which fits loosely into a shallow cylindrical opening 43 in a crown plate 45 with a cylindrical opening 46 formed therein, in which'a piston 47 operates. The piston 47 constitutes an anvil for the high-periodicity hammer which extends into a shallow cylindrical opening 50 of the helmet, where the base of the cushion block assembly 20a would normally fit.

A readily removable cushion block 20a-is customarily fited between the hammer base and the core head so that the ram blow may project thecore head away from the hammer base without injury to the hammer. The upper section of the crown plate 45 may be formed to fit the conical cavity in the base of the hammer so as to have an integral cushion block assembly.

The crown plate 45 with its opening 46 constitutes the cylinder for the high-periodicity hammer in which piston 47 has a relatively short stroke.

When the piston 47 is at the top of its stroke, compressed air or steam entersthrough an auxiliary hose connection 51 and through passage 52 which discharges centrally into the cylindrical opening 46 at the top above piston 47. This compressed air or steam immediately forces the crown plate 45 upwardly in a short stroke until the exhaust openings 55 are above the piston 47 and the compressed air or steam is thus immediately exhausted from the cylinder, permitting the piston to again move to the top of its stroke by the action of the weight of the crow plate 45 and the heavy hammer mounted thereon.

In this way the crown plate 45 moves rapidly downward and imparts a hammer blow to the helmet, either directly on 14 or through the piston 47. If the pile is operating through silt or other soft formation, the high frequency operation of the auxiliary hammer will cause :the pile to advance rapidly and almost continuously until a hard formation is reached. At the same time the operation of this auxiliary hammer does not in any way interfere with the less frequent blows of the heavy hammer :already described. By means of Valve 56 the small highfrequency hammer may be turned on or off at will. The fluid acting above the piston 47 cushions any sharp impact that may result when fluid under pressure is lifting the crown plate 45 when the ram point 21 strikes disk 20d. In a system as shown in FIG. 4, to be explained later, the pressure tank 81 and the feed lines act as an accumulator absorbing any pressure increase.

When it is apparent to the operator that the core and easing are advancing to a very small extent on each blow of the heavy hammer, he will'then close a valve 56 in auxiliary hose 51 thereby stopping the action of the small high-frequency hammer. Thus the action of the large hammer can be used in the ordinary way to ascertain when the pile has driven sufiiciently into solid formation to meet the engineering specifications, whereupon the hammer will be stopped and both the heavy hammer and the high-frequency hammer structures and the pile helmet and the core if one is being used, will be removed and utilized on another pile.

Although the main downward driving force on the pile is generated when the heavy ram of the main hammer strikes, there is also a reactive downward force on the pile when the ram is lifted for the next blow. This reactive downward force of the main hammer is generally not enough to keep the pile moving between blows. When the high-frequency intermediate hammer lifts the entire main hammer assembly, or the entire core and hammer assembly, it is also putting a more closely spaced downward force on the pile, which, coupled with the dropping of the weights operated by the intermediate hammer, tends to keep generating almost a continuous downward thrust on the pile, even though the ram of the main hammer may only be striking 50 to 150 blows per minute. When the operator desires to operate only the high-frequency hammer, the main hammer may be shut off by closing valve 83 on line 35.

Referring now to FIG. 3, instead of interposing the high-frequency hammer between the heavy hammer structure and the crown at the top of the pile, the high-frequency hammer may be mounted in the bottom of the pile core 64. As here shown, a piston 60 is mounted in a'cylinder 61 which is secured by bolts 62 and 63 to the lower end of the core 64. Pipes or hose 65 and 66 extend upwardly through the entire length of the pile and jut out near the top through cycle valve 67. Inlet pipe orhose 68 supplies compressed air or steam through the cycle valve which is so arranged that in one position the compressed air or steam passes downwardly through pipe 65 and'enters the cylinder 61 above the piston 60, whereby the cylinder, the core and the low-frequency hammer are given an upward thrust which is immediately followed by the opening of the exhaust pipe 66 by the action of the cycle valve through which the compressed air or steam is allowed to quickly exhaust. Thus the entire weight of the core and the cylinder of the low-frequency hammer is released and falls thereby imparting a hammer blow upon the hammer head 70 and upon the bottom plate 11 and on any shoulders contacted by the core as at 13a. The cycle valve may be operated by a small motor, not shown, or any suitable means.

This will not in any way interfere with the action of the heavy hammer acting on the top of the core, and nevertheless this auxiliary hammer by its high-frequency cycle of hammer blows, will cause the core and the casing to pass very rapidly through silt or relatively soft formations.

As above stated, the high-frequency hammer in its action requires that the entire weight of the core and the low-frequency hammer is raised, and if the available steam or air pressure is relatively low, usually in the order of 100 pounds per square inch, it may be necessary or desirable to utilize the steam or air in a pump having a comparatively large cylinder 75, as shown in FIG. 4, having a piston 76 connected to a piston 77 in a small hydraulic cylinder 78. The cylinder 78, which then becomes a hydraulic pump, may be supplied with a substantially noncompressible liquid, such as lubricating oil, which would be forced through a check valve 80 into a pressure tank 81, and the oil would then be available directly through pipe 82 on the high-frequency hammer to lift the entire weight of the core 64' and the heavy hammer which acts on the top of the core. The outlet pipe 82 from the high pressure cylinder 81 is led directly into the pipe 68 of FIG. 3.

The pressure tank 81 may be dispensed with, and the high pressure fluid from the pump-piston 78 may be pulsed up and down in a single hose or pipe 65, by any of the well known means for pulsing a high pressure working fluid.

High pressure working fluid generated by a hydraulic pump may also be used to activate the piston 47 in the crown plate 45, if desired.

The structures illustrated may be modified in various particulars without departing from the spirit of the invention, and only such limitations should be imposed as are indicated in the appended claims.

I claim:

1. A pile driving mechanism which comprises a lowfrequency hammer in combination with a high-frequency hammer, said low-frequency hammer arranged to strike an operating member of the high-frequency hammer so as to act in the same direction as and drive through the high-frequency hammer.

2. A pile driving mechanism as defined in claim 1, including means for stopping the action of the high-frequency hammer whereby the final driving may be made solely with the low-frequency hammer and thereby be susceptible of measuring the advance of the pile per stroke of the low-frequency hammer to meet the engineers specifications for adequate load bearing capacity.

3. In combination with a core and shell pile a relatively low-frequency hammer to advance the core and shell through the earth formation, a relatively high frequency hammer to lift the entire weight of the core a relatively short distance and release it to advance the core and shell through the earth formation.

4. In combination with a core and shell pile, means positioned at the bottom of the core for lifting the entire weight of the core and releasing it to advance the core and shell through the earth formation.

5. Apparatus as defined in claim 3, wherein the highfrequency hammer is adapted to lift the entire Weight of the low-frequency hammer as well as the core and to release the low-frequency hammer and core to advance the core and shell through the earth formation.

6. A pile driving mechanism for driving a core and shell pile, comprising heavy weight hammer means for lifting a heavy Weight and permitting the weight to fall for exerting a hammer force transmitted to the core to advance the core and shell through the earth formation, and lifting means for lifting the core and heavy Weight hammer means, said lifting means releasing the apparatus lifted to provide a blow transmitted to the shell to advance the core and shell through the earth formation.

7. A pile driving mechanism as defined in claim 6, wherein said lifting means comprises a cylinder member fixed to and positioned inside the bottom of the core, a piston member having a hammer head interposed between a bottom plate of the shell and the core, and a piston head thereabove within said cylinder member, a chamber within the cylinder member exposed to a top surface of the piston head, means for introducing a fluid under pressure to the chamber to exert a relative force between piston head and cylinder member, tending to raise the cylinder member so as to lift the core, and means for discharging the fluid under pressure to cause the cylinder member and core to be dropped against the hammer heard to provide a blow against the shell.

8. A pile driving mechanism for driving a core and shell pile; comprising heavy weight hammer means for lifting a heavy weight and permitting the weight to fall for exerting a hammer force transmitted to the core, to advance the core and shell through the earth formation, and lifting means for lifting the core, said lifting means releasing said core to provide a blow transmitted to the shell to advance the core and shell through the earth formation.

9. A pile driving mechanism, comprising heavy weight hammer means including a heavy weight, said heavy Weight hammer means lifting said heavy weight and re leasing the weight to provide a blow against an object to be driven, and lifting means for lifting the heavy Weight hammer means and releasing the heavy weight hammer means to provide blows against the object to be driven.

10. A pile driving mechanism, comprising a heavy weight, lifting means for lifting the heavy weight and releasing the weight, a base member for supporting the lifting means and containing a movable surface which is struck by the heavy Weight when the weight is released, a helmet to receive driving blows, a cylinder member and piston interposed between the base member and helmet, the cylinder member having an upper surface bearing against the base member and the piston having a lower surface bearing against the helmet, a chamber within the cylinder member exposed to a top surface of the piston, means for introducing a fluid under pressure to the chamber to exert a relative force between piston and cylinder member tending to raise the cylinder member so as to lift the base member and lifting means including the heavy weight, and means for discharging the fluid under pressure to cause the cylinder member and base member and lifting means, including the heavy weight, to be dropped to provide a blow against the helmet.

11. A pile driving mechanism for driving a pile, including pile driving hammer means, a cylinder and piston interposed between said pile driving hammer means and a pile to be driven, the cylinder and piston being adapted for relative reciprocation by the introduction and exhausting of a fluid into and out of a chamber of the cylinder communicating with the piston, one of the cylinder and piston being arranged to be struck by the pile driving hammer means, the other of the cylinder and piston engaging the pile to be driven, the introduction of fluid into the chamber raising the pile driving hammer means and the exhausting of fluid dropping the pile driving hammer so as to impart a blow to the pile to be driven.

12. In a pile driving core for driving a shell pile, the combination of a cylinder and piston, the cylinder and piston being adapted for relative reciprocation by the introduction and exhausting of a fluid into and out of a chamber of the cylinder communicating with the piston, the piston and cylinder being located at the bottom of said pile driving core above the bottom plate of a shell pile to be driven by the core, the cylinder forming a part of the bottom of the core, the piston including a head contacting the bottom plate of the shell to be driven, the introduction of fluid into the chamber raising the cylinder and core and the exhausting of fluid dropping the cylinder and core so as to impart a blow to the shell to be driven.

References Cited UNITED STATES PATENTS 2,423,301 7/1947 Fairchild 173-102 3,146,835 9/1964 Hornstein 173-48 3,151,687 10/1964 Sato et al. 17346 3,283,832 1l/1966 Spannhake et al 173--126 3,286,775 11/1966 Hornstein 173-:29

FRED C. MATTERN, JR., Primary Examiner, L- P. K S LER. A i ant xamin

Claims (1)

1. A PILE DRIVING MECHANISM WHICH COMPRISES A LOWFREQUENCY HAMMER IN COMBINATION WITH A HIGH-FREQUENCY HAMMER, SAID LOW-FREQUENCY HAMMER ARRANGED TO STRIKE AN OPERATING MEMBER OF THE HIGH-FREQUENCY HAMMER SO AS TO ACT IN THE SAME DIRECTION AS AND DRIVE THROUGH THE HIGH-FREQUENCY HAMMER.

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