GB1599899A - Pile driving - Google Patents

Description

(54) IMPROVEMENTS IN OR RELATING TO PILE DRIVING (71) We, HOLLANDSCHE BETON GROEP N.V., a Dutch Company, of Generaal Spoorlaan 489, P.O. Box 81, Rijswijk (z.h.), Holland, do hereby declare the invention, for which we pray that a patent may be granted to us and the method by which it is to be performed to be particularly described in and by the following statement: This invention relates to under-water pile driving using a hammer unit having a pile sleeve at its lower end which is adapted to be located over the top of the pile to be driven and by means of which the hammer unit is supported on the top of the pile during the driving of the pile.

Under-water pile driving is practised by using a hammer unit in which the hammer is driven by hydraulic pressure and is enclosed in a casing to which compressed air is supplied to prevent the sea water from rising into the casing through the pile sleeve which is open at its bottom end. Such a hammer unit is described in British Patent Specification No. 1,388,690 and a mode of manipulating the hammer unit and supplying it with hydraulic pressure and compressed air from a barge or other vessel floating on the sea, or from a stationary structure or rig, is described in German Offenlegungsschrift No. 2,243,309. The hammer unit may comprise multiple hammers as shown in the aforesaid British Specification or a single hammer. Such hammer units are commercially marketed by the Applicants under the Trade Mark "Hydroblok".

Such hammer units are very large, present units having lengths from top to bottom, when in the upright pile driving position, of 5--14 m., diameters of 1.5S4.5 m. and weights of from 12-220 tonnes.

The manipulation and lowering of such large and heavy hammer units on to the top of a pile to be driven into the seabed by means of a crane on the vessel or structure from which the under-water pile driving is to be performed is not only difficult but also involves risk of damage to the hammer unit and to the vessel or structure. The problem, which normally arises in rougher water, is that the hammer unit acquires uncontrolled motions caused by swinging from the crane and also by the forces directly acting on the hammer unit as it is lowered into and through the water zone which is in wave motion.

The invention has for its object to avoid or reduce these uncontrolled motions and to provide a practical solution of lowering a substantially heavy hammer unit from above water and through a water zone in heavy wave motion, to be located on the top of a pile to be driven.

To this end, the invention consists in apparatus for manipulating a pile-driving hammer unit having at its lower end a pile sleeve which is adapted to be located over the top of a pile to be driven and by means of which the hammer unit is supported on the top of the pile during driving the pile, characterised in that the hammer unit is supported by guide means on an elongate support member for guided sliding movement lengthwise of the support member which is tiltable about a horizontal axis adjacent one end of the support member from a position in which the hammer unit is substantially horizontal to an uprighted position in which the hammer unit can be lowered from the support member by sliding downwards along said guide means, and subsequently hoisted into engagement with the support member sliding upwards along said guide menas whereby to guide the vertical movement of the hammer unit as it enters and leaves the water. The support member, which may be constructed as a frame, may be pivotted on a skid or other carriage on which the hammer unit may be transported.

The said guide means conveniently comprise guide channels disposed on opposite sides of the support member and in which guide bars secured along opposite sides of the hammer unit are slidably received. Conveniently the guide bars are tubular and the lowering and hoisting of the hammer unit is effected by two chains, cables or the llkc which are under control of a power drive on the apparatus and of which the free ends are respectively connected to weight members which are captive but movable within and along each of said tubular bars respectively, whereby to enable the chains to be paid out as soon as the hammer unit is seated on the pile so that the pile driving can be performed without the shock impact reacting into the hoisting chains or cables.

The vessel or structure from which the pile driving is performed may also be provided with guide means corresponding to, below, and aligned with the guide means on the support member, when uprighted, whereby to provide further guidance for the hammer unit during its lowering into or hoisting out of the water.

In order that the invention may be more clearly understood, reference will now be made to the accompanying drawings, in which: Fig. 1 diagrammatically shows one embodiment of apparatus according to the invention, the tiltable frame and the hammer unit thereon being in the horizontal position, Fig. 2 shows the tiltable frame in the uprighted position, Fig. 2A is a section along the line A-A of Fig. 2, Fig. 3 is a view similar to Fig. 2 with the hammer unit partially lowered towards a pile, Figs. 3A, 3B and 3C are sections along the lines PB, C-C and D-D respectively of Fig. 3, Fig. 4 is a view similar to Fig. 3 while the pile is being driven, Referring to the embodiment illustrated in the drawings, a hammer unit 1 having a pile sleeve and suitable for under-water pile driving is shown in Fig. 1 supported on a tiltable elongate support member in the form of a frame 2 pivotted for turning about a horizontal axis adjacent one of its ends on pivots 3 at one end of a carriage, shown in the form of a skid 4, resting on the deck of a barge 5 from which the pile driving operation is to be performed and on which is located the machinery for producing the hydraulic pressure required for operating the hammer and the compressed air to be fed to the casing of the hammer unit 1. Hydraulic pressure and compressed air are supplied to the hammer unit by hoses 6 conveniently arranged side-by-side to form a ribbon.The hoses 6 are stored on a powered hosereel 7 mounted on the skid 4.

The hammer unit 1 is supported in the tiltable frame 2 by two tubular bars 8 ex tending along the outside of the casing of the hammer unit (see Figs. 2A and 3) and disposed at diametrically opposite sides there of, the said bars being slidably engaged res pectively in two opposed guide channels 9 ex tending along opposite sides of the tiltable frame 2 and carried by the side members 10 of the tilting frame.

Movable in each of the tubular bars 8 is a weight member 11 (see Figs. 3 and 4) each of which is captive in its respective tubular bar, that is movement of a weight is blocked when it reaches the ends of its tubular bar.

The weight members 11 are connected respectively with two hoist chains 12 which extend out of the upper end of the respective tubular bars 8 (see Fig. 3) and are coupled to a powered double chain drive 13 mounted on the tiltable frame 2 (see Figs. 1, 2, 3 and 3B).

When the tiltable frame 2 with the hammer unit 1 supported therein is in the horizontal position shown in Fig. 1, they may be moved on the skid 4 further inboard of the barge to facilitate inspection and maintenance of the hammer unit. When the hammer unit is to be put into use the skid 4 is moved to the position shown in Fig. 1, secured in this position, and the tiltable frame 2 is uprighted, for example by hydraulic cylinder means (not shown) to the position shown in Fig. 2. The frame is held in this position by the upright bracket 4a on the skid 4 and the locking bolts 14.

The hoses 6, which have been connected to their respective connections on the hammer unit when in its horizontal position, extend over a guide drum 15 (see Figs. 3 and 3A) at the top of the tiltable frame 2 (when uprighted).

The hammer unit 1 is lowered by the powered double chain drive 13, the hammer unit being guided in the hammer guides 9 during the initial lowering movement. Preferably the barge 5 is equipped with lower hammer guides 16 secured to the hull of the barge in alignment with the guides 9 (see also Fig. 3C) so that the hammer unit is fully guided while passing the waterline W.

The hose ribbon is connected to the hoist chains at 17 (Figs. 3 and 4) so as to maintain a loop for the hoses between the connection 17 and the hammer unit as the hammer unit is lowered on to the pile 18 and the pile sleeve 19 of the hammer unit is located on the top of the pile. Further paying-out of the chains 12 causes the weights 11 to move to the bottom ends of the tubular bars 8 (see Fig. 4), thus leaving the hammer unit fully supported on the pile 18 so that operation of the hammer unit will drive the pile without hammer-blows becoming active on hoses 6 and chains 12. The chains 12 are further paid oat, before the hammer unit has lowered through a distance L, and so on, until the pile has been driven to the desired extent, whereafter the chains 12 are hoisted, causing the weights 11 first to move to the upper ends of the bars 8 and then to hoist the hammer unit until its bars 8 are guided into the hammer guides 16, 9 and again reaches the position shown in Fig. 2.

The frame 2 may then be tilted back with the hammer unit in its horizontal position as shown in Fig. 1, bringing the hammers centre of gravity as low as possible to the deck of the vessel and facilitating transport of the skid inboard of the vessel for stowage and/or servicing.

While a particular embodiment has been described, it will be understood that various modifications may be made without departing from the scope of the invention. For example more or less than two hoisting chains or the like may be used. Further the powered drive for the chains may be mounted on the skid 4, for example at 13a (Fig. 1).

The lower hammer guides 16 may also be made longer, for example as indicated at 16a in Fig. 1.

WHAT WE CLAIM IS:- 1. In the art of underwater pile driving, apparatus for manipulating a pile-driving hammer unit having at its lower end a pile sleeve which is adapted to be located over the top of a pile to be driven and by means of which the hammer unit is supported on the top of the pile during driving the-pile, characterised in that the hammer unit is supported by guide means on an elongate support member for guided sliding movement lengthwise of the support member which is tiltable about a horizontal axis adjacent one end of the support member from a position in which the hammer unit is substantially horizontal to an uprighted position in which the hammer unit can be lowered from the support member by sliding downwards along said guide means, and subsequently hoisted into engagement with the support member by sliding upwards along said guide means, whereby to guide the vertical movement of the hammer unit as it enters and leaves the water.

2. Apparatus according to claim 1, characterised in that said guide means comprise guide channels disposed on opposite sides of the support member and in which guide bars secured along opposite sides of the hammer unit are slidably received.

3. Apparatus according to claim 2, characterised in that said guide bars are tubular, and in that the lowering and hoisting of the hammer unit is effected by two chains, cables or the like, which are under control of a power drive on the apparatus and of which the free ends are respectively connected to weight members captively movable within and along each of said tubular bars respectively.

4. Apparatus according to claim 1, 2 or 3, characterised in that the vessel or structure from which the pile driving is performed is also provided with guide means corresponding to, below, and aligned with the guide means on the support member when in its uprighted position, whereby to provide further guidance for the hammer unit during its lowering into and hoisting out of the water.

5. Apparatus according to any preceding claim, characterised in that said horizontal axis is provided by a pivotal connection between the support member and a carriage on which the support member rests and may be transported when the hammer unit is in its substantially horizontal position.

6. Apparatus according to claim 5, characterised in that the carriage supports a powerdriven reel for the hoses through which hydraulic pressure and compressed air may be supplied to the hammer unit, and in that the support member carries means for guiding the hoses as the hammer unit is lowered and hoisted.

7. Apparatus according to claim 1, characterised in that the hammer unit, having at its lower end a pile sleeve which is adapted to be located over the top of a pile to be driven and by means of which the hammer unit is supported on the top of the pile during driving the pile, comprises a casing which encloses a hydraulically-actuated hammer mechanism and is adapted to be supplied with compressed air to keep the hammer mechanism out of contact with ambient water during under-water pile driving, two tubular guide bars being secured respectively along opposite sides of the hammer unit outside of said casing and extending in the top to bottom direction of the unit, and by two weights respectively captively movable along a tubular guide bar and adapted to be attached to respective hoisting chains, cables or the like.

8. Apparatus for manipulating a pile-driving hammer unit constructed substantially as hereinbefore described with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (8)

**WARNING** start of CLMS field may overlap end of DESC **. The frame 2 may then be tilted back with the hammer unit in its horizontal position as shown in Fig. 1, bringing the hammers centre of gravity as low as possible to the deck of the vessel and facilitating transport of the skid inboard of the vessel for stowage and/or servicing. While a particular embodiment has been described, it will be understood that various modifications may be made without departing from the scope of the invention. For example more or less than two hoisting chains or the like may be used. Further the powered drive for the chains may be mounted on the skid 4, for example at 13a (Fig. 1). The lower hammer guides 16 may also be made longer, for example as indicated at 16a in Fig. 1. WHAT WE CLAIM IS:-

1. In the art of underwater pile driving, apparatus for manipulating a pile-driving hammer unit having at its lower end a pile sleeve which is adapted to be located over the top of a pile to be driven and by means of which the hammer unit is supported on the top of the pile during driving the-pile, characterised in that the hammer unit is supported by guide means on an elongate support member for guided sliding movement lengthwise of the support member which is tiltable about a horizontal axis adjacent one end of the support member from a position in which the hammer unit is substantially horizontal to an uprighted position in which the hammer unit can be lowered from the support member by sliding downwards along said guide means, and subsequently hoisted into engagement with the support member by sliding upwards along said guide means, whereby to guide the vertical movement of the hammer unit as it enters and leaves the water.

2. Apparatus according to claim 1, characterised in that said guide means comprise guide channels disposed on opposite sides of the support member and in which guide bars secured along opposite sides of the hammer unit are slidably received.

3. Apparatus according to claim 2, characterised in that said guide bars are tubular, and in that the lowering and hoisting of the hammer unit is effected by two chains, cables or the like, which are under control of a power drive on the apparatus and of which the free ends are respectively connected to weight members captively movable within and along each of said tubular bars respectively.

4. Apparatus according to claim 1, 2 or 3, characterised in that the vessel or structure from which the pile driving is performed is also provided with guide means corresponding to, below, and aligned with the guide means on the support member when in its uprighted position, whereby to provide further guidance for the hammer unit during its lowering into and hoisting out of the water.

5. Apparatus according to any preceding claim, characterised in that said horizontal axis is provided by a pivotal connection between the support member and a carriage on which the support member rests and may be transported when the hammer unit is in its substantially horizontal position.

6. Apparatus according to claim 5, characterised in that the carriage supports a powerdriven reel for the hoses through which hydraulic pressure and compressed air may be supplied to the hammer unit, and in that the support member carries means for guiding the hoses as the hammer unit is lowered and hoisted.

7. Apparatus according to claim 1, characterised in that the hammer unit, having at its lower end a pile sleeve which is adapted to be located over the top of a pile to be driven and by means of which the hammer unit is supported on the top of the pile during driving the pile, comprises a casing which encloses a hydraulically-actuated hammer mechanism and is adapted to be supplied with compressed air to keep the hammer mechanism out of contact with ambient water during under-water pile driving, two tubular guide bars being secured respectively along opposite sides of the hammer unit outside of said casing and extending in the top to bottom direction of the unit, and by two weights respectively captively movable along a tubular guide bar and adapted to be attached to respective hoisting chains, cables or the like.

8. Apparatus for manipulating a pile-driving hammer unit constructed substantially as hereinbefore described with reference to the accompanying drawings.