US3391435A - Hydraulic clamping system for vibrodrivers - Google Patents

Description

} -J. LEBELLE 3,391,435

I HYDRAULIC CLAMPING SYSTEM FOR VIBRODRIVERS Filed June 15. 1967 July 9, 1963 3 Sheets-Sheet 3 mvsuroa. J64 400/5 was:

Jrraewars United States Patent 3,391,435 HYDRAULIC CLAMPING SYSTEM FOR VIBRODRIVERS Jean L. Lebelle, 35 Rue Gounod, Saint-Cloud, Hauts-de-Seine, France Filed June 15, 1967, Ser. No. 646,264 12 Claims. (Cl. 24-263) ABSTRACT OF THE DISCLOSURE A vibrodriver clamping system in which a clamp actuating hydraulic jack is supplied with pressurized liquid by an electric motor-driven pump that is controlled by the pressure of said liquid. The pressure of the liquid trapped by a check valve in the high pressure section of the system when the motor is deenergized maintains the jack in clamped condition. The hydraulic jack actuated clamp has an anvil and a movable jaw between which two parallel rods are slidable to grip a Z-piling in either of two mirror-reversed positions. The hydraulic jack actuated clamp is fixed to an intermediate block shiftable on the vibrodriver and an auxiliary hydraulic jack fixes the block to the vibrodriver shortly after the clamp-actuating hydraulic jack is rendered eifective.

BACKGROUND OF THE INVENTION Field of the invention A vibrodriver clamp actuated by a hydraulic jack to which liquid under pressure is supplied through a check valve by a motor driven pump, the motor being shut off when the liquid reaches a predetermined value. The liquid trapped when the motor stops keeps the clamp closed. When leakage of liquid drops the pressure to a lower predetermined value the motor is restarted. Two parallel rods in substantial transverse registration are supported for axial slidable movement between the anvil and movable jaw of a clamp so that they can grip a Z-piling in either of the two mirror-reversed positions in which it may be oriented for driving or extraction in a string of Z-pilings. The clamp and its hydraulically actuated jack are fixed to an intermediate block that, in turn, is shiftably supported from the vibrodriver so as to permit the clamp as it is closed to adjust its position to an elongated element to be driven into or extracted from the ground. A second hydraulic jack is arranged to be actuated by the same pressurized liquid as the first jack but with a slight time delay. The second jack locks the intermediate block to the vibrodriver.

Description of the prior art A vibrodriver is used to drive into or extract from the ground an elongated member such as a pile, stake, post or piling. A vibrodriver includes a set of counterrotating balanced eccentric weights the components of the centrifugal forces of which along an axis of vibration are additive. The components of said centrifugal forces perpendicular to said axis cancel each other out. To be effective the vibrodriver must be fixed to the ground engaging member so as to be, effectively, functionally unitary therewith. Previously two systems were used to achieve detachable fixing. In the first system bolts or wedges firmly fastened the vibrodriver to an end of the ground engaging member. In the second system an end of the ground engaging element Was gripped by a clamp the jaws of which were squeezed together by a hydraulic jack. Either both jaws were movable toward and away from one another, like a pair of pliers, or one jaw was fixed, i.e. was an anvil, while the other jaw was movable, like a vise.

3,391,435 Patented July 9, 1968 The first system is so tedious and delicate to manipulate that its use has been essentially discontinued.

The second system is speedy and simple to operate, but it has certain drawbacks. As pointed out above the clamp must secure the vibrodriver to an end of the ground engaging member so firmly that no relative movement can be experienced, i.e. there must be no play. The pressure exerted on the clamp by the hydraulic jack is intended to fulfill this purpose. To perform properly the force provided by the hydraulic jack should be predetermined and should vary only slightly from that value. If the force is too low the clamp may shake loose or may slide on the elongated member so that the vibrations no longer will be transmitted thereto. If the force is excessive the hydraulic jack or the clamp may be broken or the elongated member may be crushed by the clamp. This problem has been overcome by having the pump that supplies pressurized liquid operate continuously and by including in the high pressure section of the system fed by the pump an automatic discharge valve, that is to say a valve that opens to relieve pressure in excess of the predetermined pressure by discharging liquid to low pressure, e.g. a sump or reservoir. But this solution raises fresh drawbacks. Principally its disadvantages are that it uses too much power running the pump continuously and that it involves a high cost of maintenance because the valve wears out quickly since it opens and closes in quick succession practically without letup.

Another drawback of the second system arises when the hydraulic clamps are used to drive or extract Z-piling. Heretofore the clamps likewise were of Z-shape to match the configuration of this Z-piling. However in a string of interconnected Z-pilings consecutive pilings are disposed in mirror symmetry in relation to a plane perpendicular to the general line of the string and passing through the lock joining said pilings. Hence consecutive pilings present mirrored identical cross-sectional configurations. Therefore two different clamps of mirror matching configurations had to be employed, one for even pilings and the other for odd pilings, but neither for both pilings. I

A third drawback of the second clamping system occurs when the hydraulically operated clamp is bodily shiftable with respect to the vibrodriver with the aid of an intermediate block that can be fixed to the vibrodriver by an auxiliary hydraulic jack other than the jack which actuates the clamp. This arrangement is usually found in vibrodrivers having two or more hydraulically actuated clamps separated from one another. The arrangement is employed, for example, to grip separately the two offset flanges of a Z-piling, or to grip separately the ends of two previously interconnected piles, or to grip separately diametrically opposed segments of a tubular pile. At one time the two clamps were mechanically fixed at the desired distance apart. Subsequently, but prior to this invention, it was proposed to shiftably mount each clamp on the vibrodriver and to fix the clamp with respect to this vibrodriver by an auxiliary hydraulic jack, the auxiliary jacks and the principal (clamping) jacks being fed from the same high pressure oil line that actuated all of the jacks simultaneously. The drawback of such arrangement is caused by the fact that the pile, or piles, although superficially similar, vary somewhat in shapes and dimensions. The use of at least one clamp shiftable on the vibrodriver ameliorates the problem by permitting a regulation of the spacing between two clamps, but because all the jacks are concurrently energized the clamps have insufficient time to adjust themselves to their correct relative positions before being immobilized on the vibrodriver actuation of the locking auxiliary hydraulic jacks. This then causes excessive mechanical deforming forces to be exerted on the clamps.

3 SUMMARY OF THE INVENTION It is an object of the present invention to provide an improved vibrodriver hydraulic clamping system which overcomes the foregoing drawbacks.

It is another object of this invention to provide a system of the character described in which the clamp actuating hydraulic jack is supplied with pressurized liquid by an electrically driven pump having in its electrical feed circuit a pressure-sensitive relay that controls energization and de-energization of the pump when the pressure of the hydraulic fluid supplied to the jack reaches, respectively minimum and maximum predetermined values.

It is another object of the present invention to provide a system of the character described employing an off-andon pump energizaiion wherein a check value is interposed between the pump and the clamp actuating hydraulic jack to trap liquid under high pressure in the jack when the pump is de-energized.

It is another object of the present invention to provide a system of the character described employing an off-andon pump energization wherein a pressure storage element, such as an accumulator, is branched off the hydraulic feed circuit for the jack and includes a body of gas to smooth out pressure variations in the hydraulic feed circuit and to protract energization and de-energization pe riods of the pump.

It is another object of the present invention to provide a vibrodriver hydraulically actuated clamp for Z-piling which clamp can grip Z-piling in either mirror-reversed position thereof.

It is another object of the present invention to provide a vibrodriver hydraulicaly actuated clamp for Z-piling which clamp includes an anvil and a hydraulically movable jaw spaced therefrom, there being two axially slidable parallel rods extending in a direction between the anvil and jaw whereby, depending on the position of the Z-piling in the clamp, the flanges of the Z-piling either will be gripped between the movable jaw and one end of a first rod and between the anvil and one end of the second rod, or will be gripped between the movable jaw and the other end of the second rod and between the anvil and the other end of the first rod.

It is another object of the present invention to provide a principal hydraulic jack actuated clamp shiftably mounted by an intermediate block on a vibrodriver to which it is locked by an auxiliary hydraulic jack, both jacks being fed by a common high pressure hydraulic line, the auxiliary jack through a delay mechanism, so that the clamp will grip an elongated member, accommodating itself to a proper position thereon, and only thereafter will the auxiliary jack fix the position of the clamp relative to the vibrodriver.

It is another object of the present invention to provide a principal hydraulic jack actuated clamp shiftably mounted by an intermediate block on a vibrodriver to which it is locked by an auxiliary hydraulic jack, both jacks being fed by a common high pressure hydraulic line, wherein the principal jack is actuated before the auxiliary jack so that the clamp will grip an elongated member, accommodating itself to a proper position thereon, and only thereafter will the auxiliary jack fix the position of the clamp relative to the vibrodriver.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings in which are shown various possible embodiments of the invention,

FIG. 1 is a front elevational view of a conventional vibrodriver with a conventional clamp and a conventional clamp actuating hydraulic jack, the same being shown only for the purpose of illustrating a complete vibrodriver hydraulic clamping system embodying the present invention;

FIG. 2 is a hydraulic and electric circuit diagram, shown in conjunction with a schematically illustrated clamp and jack, of a jack pressure regulating circuit according to the present invention;

FIG. 3 is a schematic top plan view of an interconnected string of Z-pilings;

FIG. 4 is a side view of a modified form of clamp, according to the present invention, for gripping a Z-piling in either one of its two mirror-reversed positions;

FIG. 5 is a sectional view taken substantially along the line 5-5 of FIG. 4; and

FIG. 6 is a vertical sectional view through another modified form of clamp, according to the present invention, including a hydraulic circuit diagram for automatically actuating the principal jack that closes the clamp before actuating the auxiliary jack that fixedly secures the clamp carrying intermediate block to the vibrodriver.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now in detail to the drawings, and, more particularly to FIG. 1, the reference numeral 10 denotes an apparatus for driving into or extracting from the ground an elongated member such as a pile, post, stake or piling of any of the multitude of configurations and constructions that are well known to the art. The apparatus 10 includes a vibrodriver 12, a head 14 functionally unitary with the vibrodriver, a fixed jaw 16, i.e. anvil, which may be rigidly secured to the head, a movable jaw 18 mounted on the head for movement toward and away from the anvil, and a principal hydraulic jack 20 for actuating the movable jaw. A feed line 22 supplies hydraulic fluid to the principal jack.

Briefly the vibrodriver includes a casing 24 which houses a pair of parallel horizontal shafts 26 journalled in the front and back walls of the casing. The shafts carry sheaves 28 that engage belts 30 trained about sheaves 32 on the shafts of electric motors 34. These latter may, as illustrated, be mounted on the exterior of the casing 24. Fast on the shafts 26 are identical gears 36 which mutually mesh at a vertical plane located centrally of the casing 24, ensuring synchronous rotation of the shafts 26 in 0pposite directions. Each of the shafts has fixed thereon an eccentric weight 38. The weights are so disposed that they pass through the tops and bottoms of their orbits at the same instants but in opposite directions so that the weights will develop centrifugal forces the components of which along the vertical axis of the vibrodriver are additive while their horizontal components perpendicular to said axis cancel out one another. Thus a vibratory force will be developed along the central vertical axis of the vibrodriver.

At the top of the casing there is provied a perforated car 40 to facilitate suspension of the apparatus 10.

The jaws 16, 18 form a clamp for detachably engaging an elongated member to be driven into or retracted from the ground.

The hydraulic jack 20 for operating the clamp constitutes a cylinder 42 in which a piston 44 may be reciprocated by hydraulic forces in both directions. Or as is shown here the piston is shifted by hydraulic force in only one direction which is for closing movement of the clamp and biasing means is provided to move the piston in the return (opening) direction;

The piston is connected to a shaft 46 which carries the movable jaw 18 of the clamp. The feed line 22 communicates with the side of the cylinder 42 opposite to that in which the shaft 46 is located. Thereby introduction of liquid under high pressure into the feed line 22 will force the movable jaw 18 toward the anvil 16. A helical return spring 48 encircles the shaft 46 and is under compression between an end of the cylinder 42 and the facing surface of the piston 44.

Pursuant to a feature of the present invention a hydraulic and electric circuit (shown schematically in FIG. 2) is provided to supply liquid under pressure to the feed line 22 in such a fashion that high pressure is maintained in the feed line while the clamp is to be held closed yet the pressure is maintained without constant operation of the hydraulic pump.

The aforesaid circuit includes a hydraulic pump 50 driven through a coupling 52 by a three-phase electric motor 54. The motor is supplied from an alternating source of three phase 440 volt power 56 by leads 58. The leads are interrupted by a contactor 60 having an actuating coil 62 and three pairs of contacts 64 interposed in the different leads 58. The contacts 64 are normally open, that is to say they are open when the coil 62 is idle.

The intake (low pressure) side of the pump 50 is connected by a conduit 66 to an oil reservoir 68. The outlet (high pressure) side of the pump 50 is connected by conduit 70 to a distributor 72. A return conduit 74 runs from the distributor 72 to the reservoir 68. The two conduits 70, 74 are on the inlet (pump-reservoir) side of the dis tributor. A pair of conduits 76, 78 are disposed on the outlet (jack) side of the distributor.

The distributor is, in essence, a valve which includes a valve body 80. The body has two sets of passageways indicated by the arrows in FIG. 2. The body may occupy either one of two positions. In the position shown in FIG. 2 one set of passageways connects the conduit 79 to the conduit 76 and connects the conduit 74 to the conduit 73. As soon will be appreciated, the directions of liquid flow through the distributor in this position are as indicated by the arrows. In the second position of the body the other set of passageways connects the conduit 70 to the conduit 78 and connects the conduit 74 to the conduit 76. As also will soon be seen, in this second position of the body the directions of the flow are as indicated by the arrows.

The jack feed line 22 is connected to the conduits 76, 78 by a controlled check valve 82 the primary purpose of which is to allow fluid under pressure to flow from the pump 50 to the cylinder 42 and, when the pump stops, to trap the high pressure liquid in the portion of the system between the check valve and the high pressure side of the piston 44.

The controlled check valve 82 has a top chamber 84, an intermediate chamber 86 and a bottom chamber 88 in axial alignment. A piston 91 is slidable in and separates the top chamber and the intermediate chamber. The check valve body 92 is adapted to be abutted against a valve seat 94 located between the intermediate chamber and the bottom chamber. A spring 96 biases the check body 92 against the seat 94. A spindle 98 connects the piston 90 to the check valve body 92. The conduit 78 communicates with the top chamber 84. The conduit 76 communicates with the intermediate chamber 86. The feed line 22 communicates with the bottom chamber 88.

In the illustrated position of the distributor body 80 with the left hand set of passageways effective, when the pump 50 is running liquid under pressure will flow from the conduit 76 into the intermediate chamber 86 and will open the check valve body 92 against the spring 96 to permit high pressure liquid to flow to the jack cylinder 42. In the alternate position of the distributor body with the right hand set of passageways effective, when the pump is running high pressure liquid therefrom will flow through the conduit 70 to the conduit 78 causing the check valve body 92 to be unseated and allowing oil under pressure from the cylinder 42 to flow into the conduit 76 and from there to the conduit 74 which is connected to the reservoir 63.

When the pump 50 is turned off the spring 96 will urge the check valve body 92 against its seat 94 and if at this time the oil present in the system from the feed line 22 to the cylinder 42 is under high pressure it will be trapped at such high pressure. Thus, the distributor 72 insures flow of the oil in a direction from the reservoir to the pump to the jack when the clamp is closed or being closed, i.e., is in service, and the motor is running, and insures relief return of the oil in a direction from the jack to the reservoir when the clamp is open or being opened.

A relief valve 100 is connected across the pump between the conduits 66, 70. The relief valve is a onedirectional valve. It prevents how of oil in a direction from the conduit 66 to the conduit and permits flow of oil in a direction from the conduit 70 to the conduit 66. The flow of oil in the latter direction is against a strong spring 102 that tends to hold the valve closed. The spring is overcome and flow permitted to take place through the valve only when the pressure in the conduit 70 exceeds the maximum pressure which the pump can withstand. Hence, the relief valve is essentially a safety valve which only is brought into operation when there is a failure of the control system.

A conduit 104 is tapped into the feed line 22 between the controlled check valve 82 and the cylinder 42 so that said conduit 104 is in shunt with the supply line to the jack. The conduit 164 runs to an accumulator 106 and to a pressure-sensitive switch 108. The accumulator 106 and the pressure-sensitive switch 108 are thus connected in shunt with one another and with the feed line 22.

The pressure-sensitive switch 108 has a pair of contacts 110, 112. The contacts 110 are normally closed and the contacts 112 are normally open. When the oil pressure in the switch 108 reaches a predetermined maximum, the contacts 112 are closed and the contacts 110 are opened.

The distributor 72 is actuated by a coil 114 against a return spring 116. When the coil 114 is de-energized the spring causes the body of the distributor to assume the position shown in FIG. 2 in which the left-hand set of passageways is effective. When the coil 114 is energized the right-hand set of passageways becomes effective. The coil 114 is controlled by a contactor 118 having an actuating coil 120 and three pairs of normally open contacts 122, 124, 126. The pairs of contacts 122, 124, are interposed in leads 128 running from a 110-volt single phase source of power 136 to the actuating coil 114 for the distributor 72.

A twenty-four volt source of control power 132 runs to a pair of control bus lines 134, 136.

Two manually actuable push buttons 138, control pairs of contacts. The push button 138 is the clamp closing push button. The push button 140 is the clamp opening push button. The push buttons 138, 140 are interlocked in such a fashion that when the push button 138 is actuated to close its associated contacts it does not act on the push button 140 or its associated normally open contacts, but when the push button 141) is actuated to close its associated normally open contacts, the push button 138 is reversely operated to open its associated contacts. The push button 138 is atfiliated with the motor control coil 62 and the push button 140 is affiliated with the distributor control coil 120.

Also provided are: a horn 142, a manually controlled switch 144 for the horn, a normally closed motor thermal switch 146, and a lamp 148.

A first circuit runs between the control bus lines 134, 136 in series through the contacts 110, the contacts controlled by the push button 138, the motor control coil 62 and the thermal switch 146. A second circuit runs between the control bus lines 134, 136 in series through the contacts 110, the manually controlled switch 144 and the horn 142. A third circuit runs between the control bus lines 134, 136 in series through the contacts 112 and the lamp 148. A fourth circuit runs between the control bus lines 134, 136 in series through the contacts 126, the motor control coil 62 and the thermal switch 146.

A fifth circuit runs between the control bus lines 134, 136 in series through the normally open contacts 140 and the distributor control coil 120.

The operation of the circuit is as follows:

Assume the apparatus to be idle. The clamp closing button 138 is in motor off position with its contacts open. The clamp opening button 140 is in clamp closed position with its contacts open. The body 80 has its left-hand set of passageways effective. The motor 54 and pump 50 are at rest. The hydraulic jack is without pressure. The pressure-sensitive switch is in its down (low pressure) position, so that the contacts 110 are closed and the contacts 112 are open. Switch 144 is closed. The horn 142 is sounding and the lamp 148 is out. The thermal switch 146 remains closed as long as the motor 54 is not overheated.

To start operation, the clamp closing button 138 is moved to motor on position to close its contacts. The button 140 remains in clamp closed (idle) position with its contacts open. Current flows through the first circuit, energizing the coil 62 and closing motor contacts 64 to start the motor. Oil pressure builds up in the hydraulic jack to close the clamp. Oil pressure also builds up in the accumulator 106 and in the pressure-sensitive switch 108, compressing the air in the accumulator above the body of oil therein and lifting the membrane 152 against the opposing force of the spring 150. When the oil pressure has reached a predetermined high value the pressure-sensitive switch 108 operates to open the contacts 110 and close the contacts 112. Thereby, the coil 62 is de-energized to open the contacts 64 and stop the motor 54. Also, the horn 142 is de-energized. Furthermore, the lamp 148 is lit.

When the pump stops, the check valve body 92 closes against its seat 94 under the action of the spring 96, since the valve is no longer held open by high pressure in the conduit 76. Hence, oil at high pressure is trapped in the system between the valve 82 and the piston 44 and will hold the clamp closed.

The accumulator 186 due to the presence of the body of air therein, smoothes out pressure variations in the hydraulic feed line 22 for the jack. It also maintains pressure in the feed line 22 as leakage occurs from the high pressure section of the system, e.g., at the hydraulic jack, or as air in the hydraulic circuit dissolves in the oil. Eventually, as leakage continues, the oil pressure in the high pressure section of the system falls below a predetermined minimum value, causing the pressure-sensitive switch to operate to close the contacts 110 and open the contacts 112, thus restarting the motor and horn and quenching the lamp 148. The cycle of starting and stopping the motor continues so long as the clamp is to be held closed (the push button stays in contact closing position), the running and idle times of the motor and pump being protracted by the action of the accumulator 106.

To de-actuate the hydraulic jack, and thus open the clamp and release the pile gripped thereby, the button 140 is pushed to clamp open position so as to close its contacts. The button 140 is momentary, i.e., biased to a contact open position, so that it must be manually held closed for the desired time. The interlock between the two buttons causes the button 138 to shift to a position in which its contacts open as the contacts for the button 140 are closed, thereby preparing the motor to be stopped when the button 140 is released and allowed to resume its clamp closed position.

Closure of the contacts for the clamp opening button 140 completes the fifth circuit to send current through the distributor control coil 120. This closes contacts 122, 124 to actuate the coil 114, and, thereby, shift the distributor body 80 so as to render its right-hand set of passageways effective which open the check valve 82 and connect the feed line 22 to the conduits 78, 74 and, through them, to the reservoir 68. Energization of the coil 120 also closes contacts 126 completing the fourth circuit to keep the coil 62 energized and the motor 54 running. Oil pressure from the pump 66 holds the check valve 82 open while the feed line 22 is connected to the reservoir 68.

When the push button 140 is released it resumes its contact open position de-energizing the coil 120. This causes the motor and pump to stop by opening contacts 126 and de-energizing coil 62. It also de-energizes coil 114 to allow the spring 116 to shift the distributor body 89 back to its normal position in which the left-hand set of passageways is effective. Thereupon, the apparatus is ready to have the clamp reclosed upon pressing the button 138 to its contact closed condition, since the distributor is ready to direct flow of high pressure oil from the pump to the jack. However, because the motor 54 is de-energized the jack and clamp remain in open position.

FIG. 3 illustrates a string 154 of interconnected Z- pilings 156, 158 in which, for convenience, the odd numbered pilings 156 (counting from the left) have been drawn in solid lines while the even numbered pilings 158 have been drawn in dotted lines. Said view shows the mirror-reversed positions of adjacent pilings 156, 158 which heretofore has made it necessary to employ two hydraulically actuated clamps having jaws of mirrorreversed configurations or clamps which are mutually bodily shiftable in order to alternatively grip odd and even numbered pilings.

FIGS. 4 and 5 illustrate a new hydraulically actuated vibrodriver clamps 160 according to the present invention which is so constructed that the single clamp can grip either odd or even Z-pilings.

The clamp includes a frame 162 secured by bolts 164 to the head 14 depending from the vibrodriver 12. The frame has an integral pendant anvil 166 at one side and an integral pendant pillar 168 at the opposite side. The frame also has integral pendant front and back posts 170, 172 located between and spaced from the anvil and the pillar. The posts are formed with horizontal coplanar through straight bores which slidably receive a front rod 174 and a rear rod 176. The rods are longer than the widths of the posts and project from both sides thereof.

The cylinder 42 of a hydraulic jack 20 is fixed to the pillar 168 in such position that the shaft 46 carried by its piston extends toward the anvil 166. The shaft 46 at its free end carries a movable jaw 17 8 which is horizontally elongated in a front-to-back direction to such an extent that it has surface portions aligned with and facing the adjacent (left-hand) ends of the rods 174, 176. The remote (right-hand) ends of the rods 174, 176 are aligned with and face surface portions of the anvil 166.

The facing portions of the movable jaw and the anvil are parallel to one another. The rods are of the same length. The movable jaw is situated between the pillar and the posts and, specifically, between the pillar and the adjacent ends of the rods. The inner surfaces of the posts are tapered toward their centers (see FIG. 5) to accommodate the sloped webs of Z-pilings in either of the two mirroredreversed positions thereof.

Spindles 188 slidable in the pillar 168 are connected at one set of ends to opposite ends of the movable jaw 178. The other set of ends are spaced from the outer side of the pillar 168 and are in the form of heads 182. Coil springs 184 encircling the spindles are under compression between the heads 182 and the pillar 168 and bias the movable jaw 178 to a retracted position spaced from the adjacent ends of the rod 174, 176.

FIG. 5 shows how the clamp 160 is used to grip a Z-piling in either of its mirror-reversed positions. In this figure an odd numbered Z-piling 156 is shown in full lines and an even numbered Z-piling 158 in dotted lines.

When an odd numbered Z-piling 156 is to be gripped the rear flange 186 (as viewed in FIG. 5) is pressed between the movable jaw 178 and the adjacent end of the rear rod 176. The front flange 188 is pressed between the remote end of the front rod 174 and the anvil 166. The sloped web 190 angles across the space between the two posts 170, 172. The remote end of the rear rod 176 is pressed directly against the anvil 166. The adjacent end of the front rod 174 is pressed directly against the movable jaw 178.

When an even numbered Z-piling 158 is to be gripped its rear flange is pressed between the remote end of the rear rod 176 and the anvil 166. Its front flange is pressed between the adjacent end of the front rod 174 and the movable jaw 178. Its sloped web angles across the space between the two posts 170, 172 in a mirror-reversed in- 9 clination to that of the web 190. The adjacent end of the rear rod 176 is pressed directly against the movable jaw 178. The remote end of the front rod 174 is pressed directly against the movable jaw 178. The remote end of the front rod 174 is pressed directly against the anvil 166.

Thus, simply by slightly relative axially displacing the front and rear rods the clamp 160 is prepared to receive a Z-piling in either of its mirror-reversed positions and will grip said piling when oil under pressure, supplied as per the circuit of FIG. 2, is then introduced into the hydraulic jack by actuating the button 138 to close its contacts.

FIG. 6 shows a modified hydraulic vibrodriver clamping system 192 in which the pile engaging clamp is hydraulically actuated while it is shiftable on (has freedom of movement with respect to) the vibrodriver and in which thereafter the pile engaging clamp is hydraulically fixed (locked) to the vibrodriver to render ineffective the aforesaid freedom of movement. A simple form of hydraulically actuated vise clamp has been shown similar to that illustrated in FIGS. 1 and 2; other more sophisticated forms of clamp can be substituted, such, for instance, as the clamp form shown in FIGS. 4 and 5.

The system 192 is carried by a head 14 mounted on a vibrodriver 12. The system includes an intermediate block 194 having a T-shaped groove 196 in its upper surface. A T-shaped tenon 198 is slidable in the groove 196, thereby permitting the intermediate block 194 to translate relative to the head 14 parallel to the length of the tenon 198.

In order to selectively prevent relative movement between the intermediate block 194 and the head 14, an auxiliary hydraulic jack 200 is provided including a cylinder 202 and a piston 204 slidable therein. The piston mounts a sturdy pin 206 slidable in a bore in the block 194 and having the tip thereof projecting into the base of the T-groove 196 adjacent the base of the tenon 198. Conduits 208, 210 are connected to opposite ends of the cylinder 202, whereby when oil under pressure is admitted into the conduit 208 and the conduit 210 is connected to low pressure, as for instance, a reservoir, the pin 206 will forcefully engage the tenon 198 to lock the intermediate block in the position which it then occupies.

The lower end of the intermediate block 194 carries a pile engaging clamp 212 including a fixed anvil jaw 214 and a movable jaw 216. The movable jaw is actuated by a principal hydraulic jack 218 which includes a cylinder 220 in the intermediate block and a piston 222 slidable in the cylinder. Mounted on the piston is a pin 224 which is integral with the movable jaw 216. Conduits 226, 228 lead to opposite ends of the cylinder 200 whereby when oil under high pressure is introduced into the conduit 226 and the conduit 228 is connected to a source of low pressure such as a reservoir, the movable jaw will be forced against a pile P located between it and the anvil.

Pursuant to the present invention, means is provided to supply oil under pressure to the conduits 208, 226, said means being such that the oil will be supplied under pressure to the conduit 226 before being supplied under pressure to the conduit 208 whereby the clamp 212 will be actuated to grip a pile before the auxiliary hydraulic jack 200 is actuated to lock the intermediate block to the head.-

This arrangement permits the clamp 212 to adjust itself to the pile and move relative to the head 14, with the aid of the intermediate block 194, before the block is locked in the self-adjusted position of the clamp. Such an arrangement is particularly advantageous where there are two clamps and, optionally, two intermediate blocks so that clamps carried by the same vibrodriver can selfadjust their positions with respect to two points to be gripped, the spacing between which may vary in similar objects to be driven.

To the foregoing end the conduits 208, 226 are jointly connected to a conduit 230, the conduit 208 through a pair of oppositely acting check valves 232, 234. The check valves are connected in shunt with one another between the conduit 230 and the conduit 208. The check valve 232 is arranged to permit flow from the conduit 230 to the conduit 208. The check valve 234 is arranged to permit flow in the reverse direction from the conduit 208 to the conduit 230. The check valve 232 is heavily biased against opening by an adjustable spring. The check valve 234 is lightly biased against opening. Its spring need not be adjustable.

The check valve 232 is so heavily biased against opening that it will not open until the principal hydraulic jack 218 has closed its clamp 212 against a pile disposed between its jaws with sufiicient strength to firmly grip the pile. By such time the clamp 212 will have self-adjusted its position to accommodate to the location of the pile, the intermediate block 194 shifting with respect to the head 14 to permit such self-adjustment. At this time, when a high pressure has been developed in the cylinder 220, the check valve 232 will open to permit high pressure oil to flow into the cylinder 202, so as to actuate the auxiliary hydraulic clamp 200 and thereby lock the intermediate block 194 to the head 14. Thereupon the vibrodriver 10 can be set into operation. Thus, the check valve 232 constitutes a delay means which ensures actuation of the principal hydraulic jack 218 before actuation of the auxiliary hydraulic jack 200, and, concurrently, operation of the clamp 212 before the intermediate block is fixed to the vibrodriver head.

The check valve 234 is employed to enable the auxiliary hydraulic jack 200 to be de-actuated.

Both of the hydraulic jacks have been illustrated as of the opposite acting type where hydraulic pressure is employed both to close and open the jacks rather than only to close the jacks, as in the jack 20 shown in FIG. 1. It will be appreciated that, if desired, the simple form of jacks can be used in the system 192. However, the more sophisticated form has been shown by way of illustration.

The conduits 210 and 228 are connected to a conduit 236 which is designed to be connected either to high pressure or to the reservoir, as is the conduit 230, depending upon the desired mode of actuation of the two jacks, that is to say, when the conduit 230 is connected to high pressure oil and the conduit 236 to the reservoir the jacks are actuated. They are de-actuated when the connections are reversed.

A valve 238 is provided to effect the aforesaid selective connection of the conduits 230, 236. Said valve includes an inlet port 240 connected by a conduit 242 to the outlet of a motor driven oil pump 244. A port 246 is connected to the conduit 230. A port 248 is connected to the conduit 236. Ports 250 and 252 are connected to a reservoir. The ports are disposed in a valve casing 254 in which a valve body 256 is translatable under the manual control of an operator. The valve body has a right-hand position, illustrated in FIG. 6, and can be shifted to a left-hand position. The body 256 has two passageways 258, 260. The passageways are so disposed that in the right-hand position illustrated in FIG. 6 they connect the high pressure port 240 to the port 246 and the low pressure port 252 to the port 248, thereby connecting the conduit 226 and, after a short time delay, the conduit 208 to the high pressure conduit 242, while the conduits 210, 228 are connected to low pressure.

The passageways in the left-hand position of the body 256 connect the conduit 236 to high pressure and the conduit 230 to low pressure, thus allowing oil under pressure to open both hydraulic jacks, the check valve 234 permitting return flow of oil from the cylinder 202 on the-opening stroke of the auxiliary hydraulic jack 200'.

It thus will be seen that there have been provided systems which achieve the several objects of the invention and which are well adapted to meet the conditions of practical use.

As various possible embodiments might be made of the above invention, and as various changes might be made in the embodiments above set forth, it is to be understood that all matter herein described or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. A vibrodriver clamping system including a clamp, a hydraulic jack operating the clamp, a hydraulic conduit connected to the jack for leading high pressure hydraulic liquid to the jack to close the clamp against a pile, a hydraulic pump having its high pressure side connected to the conduit, an electric motor driving the pump, and a pressure sensitive switch having contacts in the motor electric supply circuit and having a pressure sensing element exposed to the pressure in the conduit, said pressure sensing element opening the contacts to idle the motor and pump when the pressure in the conduit reaches a predetermined allowable limit for the system and the pressure sensing element closing the contacts to run the motor and pump when the pressure in the conduit drops to a predetermined low value which is the minimum operating value for holding the clamp closed for vibrodriver operation.

2. A vibrodriver clamping system as set forth in claim 1 wherein means is included to trap the high pressure hydraulic liquid in the conduit when the contacts are opened by the pressure sensing element.

3. A vibrodriver clamping system as set forth in claim 2 wherein the trapping means is a check valve oriented to pass liquid in a direction from the pump to the jack.

4. A vibrodriver clamping system as set forth in claim 2 wherein the trapping means is a controlled check valve oriented to pass liquid in a direction from the pump to the jack, wherein the controlled check valve includes a mechanism to open said valve for reverse flow when the clamp is to be rendered ineffective, and wherein means further is included to connect the conduit to low pressure through the reversed opened check valve at such time.

5. A vibrodriver clamping system as set forth in claim 2 wherein an accumulator is connected to the conduit, said accumulator having a body of gas therein to smooth out pressure variations in the conduit and to protract running and idle periods of the pump.

6. A vibrodriver clamping system as set forth in claim 1 wherein a relief valve is connected across the pump to provide supplementary protection for the system, said valve opening to connect the high pressure side to the low pressure side of the pump when the pressure at the high pressure side exceeds the allowable system limit.

7. A vibrodriver clamping system as set forth in claim 1 wherein an accumulator is connected to the conduit, said accumulator having a body of gas therein to smooth out pressure variations in the conduit and to protract running and idle periods of the pump.

8. A vibrodriver clamp for engaging either of mirrorreversed Z-pilings, said clamp including an anvil, a movable jaw opposed to the anvil, a hydraulic jack for actuating the jaw, a pair of rods between the jaw and anvil, means supporting the rods with the longitudinal axes thereof parallel and mounted between the movable jaw and anvil, said last named means permitting longitudinal sliding movement of the rods relative to the movable jaw and anvil, whereby the flanges of a Z-piling will either be gripped, depending upon which of the mirror-reversed positions the Z-piling is in, between the movable jaw at one end of a first one of the rods and between the anvil and one end of the second one of the rods, or will be gripped between the movable jaw and the other end of the second rod and between the anvil and the other end of the first rod.

9. A vibrodriver clamp as set forth in claim 8 wherein the means supporting the rods comprises a pair of posts located between the movable jaw and the anvil and spaced apart transversely of the span between the movable jaw and the anvil to admit the sloped web of a Zpiling in either of its mirror-reversed positions.

10. A vibrodriver clamp including a head secured to a vibrodriver, an intermediate block, means mounting the block on the head with at least one degree of freedom of movement of the block relative to the head, an auxiliary jack, means mounting the auxiliary jack to lock the intermediate block to the head when said auxiliary jack is actuated, a pair of clamping jaws, a principal hydraulic jack, means mounting the principal hydraulic jack to open and close the jaws, a high pressure source of hydraulic liquid and selectively operable means to connect the high pressure source of hydraulic liquid first to the principal hydraulic jack and thereafter after the principal hydraulic jack has been actuated to the auxiliary hydraulic jack so as to permit the jaws to grip a pile and accommodate itself in proper position thereon and only thereafter to fix the position of the intermediate block with respect to the vibrodriver head.

11. A vibrodriver clamp as set forth in claim 10 wherein the selectively operable means includes a delay mechanism in a hydraulic conduit running to the auxiliary hydraulic jack.

12. A vibrodriver clamp as set forth in claim 11 wherein the delay mechanism is a heavily loaded check valve oriented to pass hydraulic liquid from the source of supply to the auxiliary hydraulic jack, said check valve opening at a pressure in excess of that required to operate the principal hydraulic jack.

References Cited UNITED STATES PATENTS 2,586,536 2/1952 Haller 24 263 2,714,917 8/1955 Siegerist 24-263 3,100,382 8/1963 Muller 6153.5 3,101,956 8/1963 Muller 2794 DONALD A. GRIFFIN, Primary Examiner.

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