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Title:
A CONSTRUCTION VEHICLE INCORPORATING A BOOM ASSEMBLY
Document Type and Number:
WIPO Patent Application WO/2006/133490
Kind Code:
A1
Abstract:
A self propelled machine for use in construction, the apparatus including a mounting unit; propulsion means associated with said mounting unit for moving said mounting unit over the ground or support surface; a boom associated with said mounting unit; an attachment portion associated with an outer portion of said boom; at least one attachment devices adapted to engage with the attachment portion of the boom; and a control system including at least one computer and at least one sensor to provide information to the control system, the computer system having at least one set of preset parameters for use of each of the at least one attachment device and the machine based upon the use to which the at least one attachment device is to be put.

Inventors:
FARRANT COLIN (AU)
Application Number:
PCT/AU2006/000819
Publication Date:
December 21, 2006
Filing Date:
June 14, 2006
Export Citation:
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Assignee:
FARRANT COLIN (AU)
International Classes:
E01C19/42; A47L3/02; A62B1/02; B60P1/54; B60P3/30; B66C13/16; B66C23/40; B66F11/04; E02F9/14
Domestic Patent References:
WO2001058246A12001-08-16
WO2002045482A12002-06-13
WO1999005368A11999-02-04
WO1999052354A11999-10-21
WO1998006251A11998-02-19
Foreign References:
US4839061A1989-06-13
EP0997579A22000-05-03
RU2137204C11999-09-10
JPH1179020A1999-03-23
JP2001130895A2001-05-15
Attorney, Agent or Firm:
CULLEN & CO. (239 George Street Brisbane, Queensland 4000, AU)
Download PDF:
Claims:
Claims:
1. A self propelled machine for use in construction, the apparatus including a. a mounting unit; b. propulsion means associated with said mounting unit for moving said mounting unit over the ground or support surface; c. a boom associated with said mounting unit; d. an attachment portion associated with an outer portion of said boom; e. at least one attachment devices adapted to engage with the attachment portion of the boom; and a control system including at least one computer and at least one sensor to provide information to the control system, the computer system having at least one set of preset parameters for use of each of the at least one attachment device and the machine based upon the use to which the at least one attachment device is to be put.
2. A selfpropelled machine for spreading, distributing, smoothing and/or levelling, placed and/or poured, uncured concrete, sand, gravel or like, loose spreadable materials over ground or other support surface, the apparatus including a. a mounting unit; b. propulsion means associated with said mounting unit for moving said mounting unit over the ground or support surface; c. a boom associated with said mounting unit; d. detachable screed means for spreading and/or smoothing the loose material associated with said boom; wherein said screed means includes at least a pair of screed members for contacting the loose material to be spread and/or smoothed, the screed members spaced apart in a screeding direction.
3. A self propelled machine according to claim 1 wherein the mounting unit has at least one stabilising means or assembly adapted to stabilise the mounting unit when operating on uneven surfaces or inclined surfaces, the at least one stabilizing means extendable and retractable in relation to the mounting unit.
4. A self propelled machine according to claim 1 wherein the mounting unit is provided with a rotatable support means located between a lower chassis and an upper main body main body.
5. A self propelled machine according to claim 1 further including a multistage boom assembly.
6. A boom assembly including a first boom stage, a second boom stage allowing length adjustment of the boom assembly and a third boom stage, the first boom stage associated with a boom support assembly, the third boom stage rotatably associated with the second boom stage and at least one drive means to rotate the third boom stage relative to the second boom stage.
7. A boom assembly according to claim 6 wherein the elevation of the first boom stage is accomplished by one or more hydraulic cylinders or rams and preferably, one on either side of the boom stage.
8. A boom assembly according to claim 6 wherein an outer end of the third boom stage is provided with a connection shoe allowing the attachment of different working heads or attachment devices.
9. A self propelled machine according to claim 5 further including a multidirectional pivot connector including a first connector portion, a second connector portion spaced from the first connector portion, a slewing portion associated with the first and second connector portions and adapted to allow rotation of the second connector portion relative to the first connector portion about a first axis, at least one drive means for rotation of the second connector portion relative to the first connector portion about a second axis, and at least one drive means for rotation of the second connector portion relative to the first connector portion about a third axis.
10. A multidirectional pivot connector including a first connector portion, a second connector portion spaced from the first connector portion, a slewing portion associated with the first and second connector portions and adapted to allow rotation of the second connector portion relative to the first connector portion about a first axis, at least one drive means for rotation of the second connector portion relative to the first connector portion about a second axis, and at least one drive means for rotation of the second connector portion relative to the first connector portion about a third axis.
11. A selfpropelled machine according to claim 2 wherein the screed members are spaced apart and are fixed relative to each other using a plurality of spacing members along the length of the screed members.
12. A selfpropelled machine according to claim 2 wherein during the screeding of materials, a front screed member as defined from the direction of screeding is positioned at a level higher than the required finished level of the material and a second screed member completes the finishing of the material surface to the required level.
13. A selfpropelled machine according to claim 2 wherein the screed means is associated with an automated leveling system.
14. A self propelled machine according to any one of claims 1, 4 or 8 wherein the attachment devices which are used in conjunction with the machine are chosen from the group including an articulated screeder device with compaction system, a rock drilling rig with coring capability, a concrete saw device, having vertical, horizontal or inclined capabilities, a man lifter/man cage, a forklift device, a bucket for lifting earthen materials, a post hole drill device, or ditch digging device.
15. A self propelled machine according to any one of claims 1, 5 or 9 wherein a hydraulic system for moving component associated with the machine are provided and are controlled by a control system including at least one computer system, the computer system adapted to identify the attachment device fitted to the machine and automatically adapting the hydraulic limitations of the machine dependant upon the attachment to impose limitations on operating parameters of the machine and the attachment that govern use whilst that attachment is attached.
16. A self propelled machine according to claim 15 further including at least one sensor to provide information to the at least one computer system about attributes of the attachment device when attached to the machine.
Description:
A CONSTRUCTION VEHICLE INCORPORATING A BOOM ASSEMBLY

FIELD OF THE INVENTION

The present invention relates to machines used in construction and in particular to machines and methods to spread, distribute, smooth and/or level, placed 5 and/or poured, uncured concrete, sand, gravel or like, loose spreadable materials as well as to mount various other attachments thereto.

BACKGROUND ART

An excellent description of the background to the present invention is given in United States Patent No. 4655633 to Somero et. al and is reproduced below 0 verbatim:

"In the concrete placement industry, it is necessary to "strike-off, smooth and level, i.e., "screed" areas of placed and/or poured concrete before curing.

Numerous methods and techniques for spreading and leveling the concrete have been used in the past. These include passing an edge of a two by four plank across the top 5 of the concrete as well as more sophisticated, power screeds. For instance, in the construction of bridges or highways, or even large concrete floor areas such as in warehouses, large rail or guide supported screeds are often used. Such screeds include long trusses or beams which span the width of the strip of concrete to be formed and ride on heavy guides or rails adjacent either side of the concrete strip to skim or 0 smooth the top of the concrete between the rails.

In highway construction, slip-form pavers are often used. Such pavers include self-propelled vehicles having hoppers and pouring apparatus for laying a strip of concrete followed by a screed which spreads and smooths the concrete immediately after it is placed and/or poured by the machine. Such machines run on wheels or 5 tracks and follow guide lines or strings such that the concrete strip is laid in the desired path.

Often, smaller concrete laying jobs under 50,000 square feet of those which require low slump concrete do not justify the expense of setting up heavy guides or rails and the movement of large machinery to ride on such rails. Similarly, 0 slip-form pavers are too large to justify use on such small jobs. Moreover, many previously known screeding machines have been unable to lay more than a single strip of concrete in a day since it is necessary that one edge of a previous strip be used as a form, guide or support to lay the next strip. Thus, until the previous concrete strip has

hardened, additional strips cannot be laid side by side.

Coupled ' with the above is the requirement on smaller concrete jobs of forming and/or hand finishing the. edges of the concrete areas. If such finish work together with the primary screeding of the main areas is done by hand; the task is highly labour intensive, very time consuming and expensive."

United States Patent No. 4,655,633 then provides a self-propelled apparatus including a steerable, self-propelled frame, a cantilevered boom and an auger-type, vibratory screed mounted on the boom for spreading and smoothing the concrete as the screed was moved toward the vehicle. The elevation of the screed is adjusted automatically by a screed control assembly relative to a laser beacon reference plane positioned off the apparatus such that the finished height of the concrete or other material was accurately controlled within close tolerances. The vibratory screed of U.S. Patent No. 4,655,633 also includes a rotatable auger for spreading the concrete or other material laterally with respect to the direction of movement of the screed, as well as a strike-off member for engaging the concrete behind the auger, both of which were vibrated by a screed vibration assembly on the same support.

The Somero patent then provides one alleged solution to the problems outlined. However, the Somero patent does not provide a solution to the problem of screeding material which has a "slump".

Also, whilst various machines are used on construction sites, generally a vehicle is provided for each specific purpose. For example, if a rock drill is required, a specialized rock drill 1 machine is used, if earthmoving is required, a specific earthmoving device is used and if persons or equipment needs to be lifted or moved, specific equipment is used for these purposes.

OBJECT OF THE INVENTION

The present invention is directed to a vehicle to be used, in construction, which may at least partially overcome the abovementioned disadvantages or provide the consumer with a useful or commercial choice. In one form, the invention resides in .a self-propelled screeding apparatus for spreading, distributing, smoothing and/or levelling, placed and/or poured, uncured concrete, sand, gravel or like, loose spreadable materials over ground or other support surface, the apparatus including

b. a mounting unit; c. propulsion means associated with said mounting unit for moving said mounting unit over the ground or support surface; d. a boom associated with said mounting unit; e. screed means for spreading and/or smoothing the loose material associated with said boom; wherein said screed means includes at least a pair of screed members for contacting the loose material to be spread and/or smoothed, the screed members spaced apart in a screeding direction. The mounting unit of the screeder apparatus preferably has a robust construction allowing it to withstand the conditions and workload. The mounting unit typically supports the other components of the screeder apparatus which are usually mounted on or from the mounting unit. The mounting unit preferably acts as a counterweight for the boom and screed means allowing them to extend over a working surface with stability.

The mounting unit preferably includes at least a chassis and a main body mounted on the chassis. The chassis is typically provided with the propulsion means. It is typically also provided with at least one stabilising means or assembly.

The propulsion means usually includes a plurality of wheels or similar means for locomotion. According to a particularly preferred embodiment of the invention, the propulsion means will include eight wheels, with four wheels located on each side of the chassis. The four wheels located on each side of the chassis may be further provided with a track means according to a further embodiment and dependant upon the ground surface or topology. Each of the wheels where provided are preferably pneumatic. The propulsion means may be provided as an 8-wheel drive mechanism. Preferably, the propulsion means will be a skid-steer system and typically be powered by one or more hydraulic motors engaged in hydraulic circuit(s) to drive the wheels. The hydraulic motors are preferably powerful enough to drive the screeder apparatus up a 22.5° incline or decline.

Typically, a plurality of hydraulic motors may be provided, at least one to drive the wheels located on each side of the chassis. The hydraulic motors may be capable of operating in at least two modes, namely a low speed (or high torque) mode

in which the screeder apparatus may have a velocity of approximately 20 metres per minute and a high speed (or low torque) mode in which the screeder apparatus may have a velocity of approximately 75 metres per minute .

Preferably, the. hydraulic motors may be mounted on the chassis of the mounting unit, and generally towards one end of the drive train. The hydraulic motors may be independently controlled in order to provide the skid-steer capabilities of the screeder apparatus. The hydraulic motors may be controlled remotely by an operator.

Each of the hydraulic motors for the wheels may be provided with a braking system. Preferably, the braking system is biased into the "brake applied" condition and may require hydraulic deactivation of the brakes. The hydraulic deactivation of the brakes may only occur when sufficient pressure is achieved to disengage the brakes. The brake is preferably an internal brake allowing the screeder to stop and work on steep inclines. The brake system is designed to disengage only after the hydraulic oil pressure inside the motor has built up enough to overcome the load currently being supported by the braking system. For example, if the main hydraulic oils lines were cut, damaged or removed the brakes will preferably remain fully engaged.

The mounting unit and preferably the chassis of the mounting unit has at least one stabilising means or assembly. The at least one stabilising means or assembly will typically include a plurality of outrigger type members or assemblies. The outrigger members or assemblies are preferably adapted to at least partially support the mounting unit off the ground or stabilise the mounting unit when operating on uneven surfaces or inclined surfaces.

There will generally be at least two outrigger assemblies provided on each lateral side of the mounting unit. Each of the outrigger assemblies are preferably extendable and retractable in relation to the mounting unit. Each assembly may be extendable up to 750mm outwardly from the mounting unit and can therefore provide a working platform footprint of approximately 2500mm in width.

Each outrigger assembly will preferably be a substantially L-shaped assembly with a laterally extendable and retractable body member and a depending extendable and retractable leg member.

Preferably, the outrigger assemblies will not interfere with the circle of rotation of the main body of the mounting unit. Each outrigger assembly will

typically be over-engineered to support the weight of the screeder apparatus plus a safety factor of 1000kg for example.

The mounting unit of the screeder apparatus is also preferably provided with a rotatable support means located between the chassis and the main body. The 5 rotatable support means will typically include a slewing ring assembly allowing the main body portion to be supported by the chassis and rotatable thereupon.

The slewing ring assembly may include at least two main parts, a first part associated with the chassis and a second part associated with the main body. The two parts are preferably secured relative to one another. The slewing ring assembly

10 will preferably be approximately centered on the chassis.

The two main parts of the slewing ring assembly will typically be provided with friction reducing means. The friction reducing means will generally include the parts having a smooth finish such as by plating the parts with a smooth coating such as . by chrome plating or the like. The friction reducing means may

15 include the provision of a low friction plate or the like such as a Teflon plate or similar between the two parts of the slewing ring assembly.

The slewing ring assembly will generally be provided with a drive means to drive the rotation of the main body with respect to the chassis. The drive means will generally include at least one hydraulic motor. The at least one hydraulic

20 motor may be provided with a braking system. Preferably, the braking system is biased into the "brake applied" condition and may require hydraulic deactivation of the brakes. The hydraulic deactivation of the brakes may only occur when sufficient pressure is achieved to disengage the brakes. The brake is preferably an internal brake designed to disengage only when the hydraulic oil pressure inside the motor has built

25 up enough to disengage the brake. For example, if the main hydraulic oil lines were cut, damaged or removed the brake will preferably remain fully engaged, and the rotation of the main body prevented.

The slewing ring assembly will be provided with a suitable gear assembly to accomplish the rotation of the main body. This gear assembly may

30. include elements of an epicyclic gear assembly. Preferably, the gear assembly may include an annular ring gear which is in turn driven by a planet gear. Alternatively, the gear assembly may include a ring with an outer toothed assembly which can be driven by an externally mounted toothed gear. The ring with the toothed assembly

may be provided on the chassis or the main body and a drive means to rotate the main body provided on either the main body or the chassis.

The slewing ring assembly is also preferably provided with at least one, typically substantially centrally located opening to allow the control system components such as any hydraulic and electrical connection lines to extend therethrough.

The second part of the slewing ring assembly is preferably associated with the main body. The main body generally mounts the power source of the screeder apparatus as well as the hydraulic systems and the electrical systems. The main body also mounts a centralized control system for controlling all aspects of the screeder apparatus. The centralized control system may be capable of operation in a manual or automatic mode.

Again, the main body portion of the screeder apparatus will typically have a. robust construction. The main body is associated with the slewing ring assembly such that the main body can rotate in relation to the chassis and preferably rotation about 360° is preferably possible.

The power source provided for the screeder apparatus is typically a part of the propulsion means of the screeder apparatus. The power source will generally be either a combustion engine or an electric motor (or both). The power source will typically be approximately 15 to 20 hp. The power source regardless of type, will typically power or drive the hydraulic pumps used to propel the screeder and also to move the constituent parts. The hydraulic pumps are each preferably connected to a manifold block and electrically powered, control solenoids. Typically, the control solenoids control the direction of flow of a hydraulic fluid, typically oil, through the hydraulic circuits to be in forward or reverse. .Excess oil is returned to an oil tank which may be fitted to the main body. The oil for the various hydraulic circuits may be circulated through the circuits by the various hydraulic pumps and returned to the oil tank.

The advantages of having two different engine types are that the machine may be used in a greater variety of venues. For some simple examples, the electric motor may be more suited where noise or confined spaces is a controlling factor or even ventilation such as mining and tunnels. The petrol engine could be used in the field such as general construction sites and building development sites.

Both the electric and petrol drive units will have equal capacities and capabilities, therefore it is only a matter of the surrounding environmental issues that may determine the motor requirements.

At the rear section of the main body, there are a pair of supporting arms which are typically the main anchoring and stabilizing points for the base of the boom. These support arms are preferably adapted to support loads on the boom in all directions.

The support arms also act as a major protection frame for the motor (power source), hydraulic pump(s) and all the operational systems supported and installed onto and around the main body.

At the rear of the supporting arms, there may be an allocation for a seat where the operator may be seated if the machine is constantly moving about. This seat may be designed with a folded condition when it is not required and a use condition. The seat (if provided) may be fitted with an electronic safety sensor as a cutout means when an operator is not in or on the seat. To prevent any accidents or incidents, the screeder apparatus will typically not operate with the seat in the folded down position while the operator is not seated.

All the actions of the screeder apparatus may be controlled primarily from a control panel. This is typically a small sturdily constructed waterproof box, which provides all the information to the electrical, hydraulic and power sources for the screeder apparatus. Some of the functions of the screeder apparatus may be operated automatically once initiated, but only if the operator enables the controls to automatically function. If this does not occur, then every movement and operation of the machine may require direct control using a remote control unit. The remote control unit is typically connected to the main body of the screeder apparatus via a small cable. The cable is usually protected with a protective steel flexible conduit to prevent permanent damage to the controls and to prevent uncontrolled movements. The cable may be approximately 3000mm in length allowing the operator to move freely about the screeder apparatus while maintaining full control over the apparatus. The control cable may be varied in length or a wireless remote controlled unit can be utilized if required.

The screeder apparatus may be provided with a boom assembly. The boom assembly will typically be a multistage boom assembly and typically

approximately five stages may be provided. The boom assembly will typically be a telescoping boom assembly.

In a second form, the invention resides in a boom assembly including a first boom stage, a second boom stage allowing length adjustment of the boom assembly and a third boom stage, the first boom stage associated with a boom support assembly, the third boom stage rotatably associated with the second boom stage and at least one drive means to rotate the third boom stage relative to the second boom stage.

The boom support assembly will typically include the pair of support arms provided on the main body of the screeder apparatus and the first boom stage is typically connected to the main body portion of the screeder apparatus via these support arms. The first boom stage will typically be attached to the support arms using a pin connection allowing removal and replacement and also rotation of the first boom stage (and thereby the boom assembly) about the pins. The boom will typically rotate in a vertical plane up to approximately 90°. The elevation of the first boom stage may be accomplished by one or more hydraulic cylinders or rams and preferably, one on either side of the boom stage. Typically, the cylinders may be braced to support the weight of the boom assembly. This additional bracing may reduce any lateral movements of the boom during rotation of the main body with the boom extended in a raised elevation position. As stated above, there are preferably five boom stages, with stage 1 closest to the main body and stage 5 located furthest from the main, body. Stages 1 to 4 are all approximately 1640mm in length and stage 5 may be approximately 900mm in length. The boom assembly may be capable of moving and stopping in any position between a fully extended and a fully retracted condition. When fully retracted, stages 2 to 4 will typically be received almost fully within stage 1 and the articulated stage, stage 5 may be rotated inwardly to be substantially co-planar with stage 1. When in the fully retracted condition, the boom assembly may be approximately the length of stage 1.

When fully extended, stages 2 to 4 may be extended to their full length relative to each other and stage 1 and the articulated stage, stage 5 may be rotated outwardly to be substantially co-planar with the other boom stages. When in the fully extended condition, the boom assembly may be approximately 6200mm in length.

All of the boom stages may preferably be telescopic boom stages with

respect to each other. One or more hydraulic cylinders may be associated with the boom assembly to extend and retract the boom stages. Preferably, the hydraulic cylinder will be located within the boom. However, the hydraulic cylinder(s) may be fitted externally to the boom if so required. The boom stages may be provided with friction reducing guides and preferably materials such as Teflon may be used for the guides.

The fifth boom stage may preferably be articulated with respect to the fourth boom stage allowing the fifth boom stage to rotate in a vertical orientation. This may suitably allow screeding at an angle different to the operating angle of the chassis and main body.

The drive means may be a pair of hydraulic rams to articulate the fifth boom stage.

An outer end of the fifth boom stage may be provided with a connection shoe allowing the attachment of different working heads as well as the screed means. The main working head will usually be the screed means. The connection shoe will generally attach the working heads using a pin extending through aligned openings in the connection shoe and the working head.

Preferably, the boom can only be extended in the manual operations, but it may be retracted in either manual or the automatic setting. The boom can rotate in the vertical plane from just below a horizontal level through to almost vertical. This may give the boom a range of approximately 90°, allowing it to reach approximately 7,000mm above the chassis.

The boom speed may be varied in the retract or extend operation by the operator. This can be done using a speed dial mounted on the screeder apparatus (main body). The speed control preferably adjusts the hydraulic oil pressure needed to activate the cylinders associated with the boom sections. A preset maximum pressure may be used to interrupt the operation of the boom. For example, if the screed poles were to clash then the extension or retraction operation may stop automatically once the maximum allowable pressure had been reached. To move the Screed members loaded with wet concrete. = 80 Kg of pressure. Theoretical Increase in concrete load (Varies continually) = 30 Kg of Pressure. Total maximum working pressure set for retraction. = 110 Kg of Pressure.

Typically, the connection shoe attaches a multi-directional pivot

connector.

In a third form, the invention resides in a multi-directional pivot connector including a first connector portion, a second connector portion spaced from the first connector portion, a slewing . portion associated with the first and second connector portions and adapted to allow rotation of the second connector portion relative to the first connector portion about a first axis, at least one drive means for rotation of the second connector portion relative to the first connector portion about a second axis, and at least one drive means for rotation of the second connector portion relative to the first connector portion about a third axis. The connection shoe will typically attach to the first connector portion of the pivot connector. The slewing portion may typically allow rotation about 360°. The slewing portion of the pivot connector is similar to the slewing ring assembly connecting the chassis and the main portion and may preferably, include a brake means. Preferably, the first connector portion is circular as is the slewing portion. The second connector portion is provided spaced from the first connector portion and is adapted to connect the screed members.

The drive means provided on the pivot connector will preferably be hydraulic cylinders or rams. Preferably, there will be pairs of rams provided so that movement may be accomplished in both directions. Typically, four drive means may be provided, in two pairs in relation to each of the second and third axis. Usually, a hydraulic ram may be provided in an opposed location on either side of the pivot connector such that the rams will be provided at four main cross points about the pivot connector.

Each of the hydraulic rams may extend from an upper portion of the pivot connector and attach relative to the second connector portion. The pivot connector will have a generally cylindrical cross section to facilitate rotation. The opposed hydraulic rams act in opposition to one another with the lengthening of one and the shortening of the opposed ram to accomplish pivoting of the screed members in the respective axis of rotation. The second connector portion may generally include a circular frame with a pair of sliding shoes provided to attach the screed members. The sliding shoes may preferably allow the screed members or bars to move laterally through the sliding shoes. This may allow the screed members to be moved around fixtures which may

extend into the screed path. The sliding shoes will typically be provided with friction reducing means and at least one drive means to accomplish the lateral movement of the screed members through the shoes.

Each of the sliding shoes may be an opening having a frustum-shaped cross-section with the smaller dimension of the frustum oriented downwardly. There may be a shim plate located adjacent the larger dimension of the frustum shaped opening to assist with the fit of the screed members in the sliding shoes. There will typically be a pair of sliding shoes, one provided for each screed member.

There will be a pair of screed members spaced apart in the direction of the screeding. The screed members generally extend parallel to each other and are coplanar.

The use of the multi-directional pivot connector allows the control of the screed members in virtually any orientation. Each screed member is preferably a hollow member to aid with weight reduction and the screed members are preferably rectangular in cross-section. The provision of the rectangular screed members results in the lower wall and the front wall performing most of the screeding action.

The dual screed members are spaced apart and are preferably fixed relative to each other using a plurality of spacing members along the length of the screed members. The spacing members extend between the screed members to form a substantially H-shaped configuration. The spacing members are also preferably spaced from the lower side of the screed members.

Each of the screed members is typically approximately 4500mm in length and the dual screed members are spaced from one another approximately 300mm centre to centre. Each screed member may be provided with a sliding rail to engage with the sliding shoes on the pivot connector. Each sliding rail is preferably frustum shaped in cross-section with an extension portion extending from the sliding rail to which the screed members are attached. The frustum-shaped sliding rail typically fits within the frustum-shaped sliding shoe. The correspondingly located frustum shapes preferably assist with the connection of the two components and also with controlling the position of the screed members.

At least one of the sliding rails is provided with a toothed track to facilitate the lateral movement of the screed members. A drive means is also

generally provided to drive the lateral movement.

The screed means is preferably provided with a vibration unit. There are a variety of vibration units known in the prior art, most involving the use of eccentrically mounted weights, and any vibration unit may be used. The dual screed member design is designed to give an operator more flexibility when leveling and finishing the materials being placed such as wet concrete. The dual screed pole can be rotated in the longitudinal direction, depending on the slump of the concrete being placed.

During the screeding of the materials, such as wet concrete, the front screed member (Master Pole) will push the concrete in front of it like a blade. The concrete on the front surface/side of the Master Pole will preferably be approximately

20mm to 60mm higher than the required finished level of the concrete. The height will depend on the slump of the concrete being placed at the time. The second screed member (Slave Pole) will typically only push 5mm to 20mm of concrete in front of it and will complete the finishing of the concrete surface to the required level.

The dual screed members allow the concrete to be finished off smoothly and accurately as there are two members passing over the same area of concrete.

The screeder apparatus will also preferably further include a laser leveling system. The screed poles may be adjusted at any time during the screeding operations. This adjustment may be carried out by the hydraulic system, which is preferably controlled by either small electrical signals provided from the operator's control box (manual operation) or from the signal being received from laser sensors that are transferred to the control board. Manual Controls

The control box (remote control unit) preferably allows manual operation where the operator can control the screed poles by simply turning a switch from the OFF position to an UP or DOWN position, depending on the movement required. The switch may be biased to automatically return to the OFF position once released, therefore the switch must generally be held on to continue the adjustment further.

When the switch is activated a small electrical current is sent from the switch to the solenoid of the relevant hydraulic pump, causing the solenoid to activate

accordingly. When the solenoid is activated it will allow the hydraulic oil to pass through the relevant hydraulic ram of the screeder apparatus into the cylinder causing the cylinder to extend or retract, depending on which direction the control switch was turned (UP or DOWN). If the operator wants to move the screed pole poles for an extended period, then preferably the switch must be held in the required position until the movement is completed. Automatic Controls

The automatic control board when activated may suitably control all the movements of the screed members required for leveling and retraction of the boom stages relative to the main body.

The automatic controlling system is preferably enabled by the operator from the remote control unit. The operator simply turns the operation switch from MANUAL to AUTOMATIC. This will then allow the control board to activate the hydraulic solenoids as required. The automatic control board receives signals from a plurality of laser sensors mounted relative to the 4500mm length of the screed members. The signal from these sensors may then be relayed to the control board as a small electrical current which then activates the hydraulic solenoid.

Preferably, three laser sensors are provided and allow the automatic system to control the position of the screed members according to a laser beam that is projected from a stationary laser transmitter. The laser transmitter projects a laser beam parallel to the surface (or required surface) of the material being screeded, such as concrete. The laser sensor may read its elevation in accordance with the laser beam and then sends a small electrical signal back to the control board. This signal then activates the required solenoid allowing the screed pole to be adjusted so as it is constantly working at the same height from the laser beam being transmitted.

There are preferably at least three signals that are received by the laser sensor. 1. Elevation too Low, 2. Elevation too High, 3. Correct Elevation. When the laser sensor signals the control board (for example, 3. Correct Elevation) the solenoids will lock off, holding the screed poles at this elevation until another signal is received from the sensors. The sensors may take readings from the laser beam at an approximate rate of 8 readings per second. The average of these readings is calculated and then this averaged signal is generally sent to the control board. With this amount

of constant monitoring, the screed poles are constantly adjusted automatically resulting in a uniform surface finish.

There are preferably two sensors attached to the screed members laterally, one at each end. A third sensor is preferably positioned centrally along the screed members. The two lateral sensors preferably control the screed members in the transverse elevations (angle about a central point along the screeder means), while the third sensor controls the longitudinal elevation. This allows the screeder to work in multiple planes simultaneously.

The sensors are preferably set just before the materials to be screeded are placed, such as wet concrete. To set the sensors, the screed members must be set at the correct elevation and then the laser transmitter is initialised. Each sensor may be slid up or down a staff pole (pole used to secure the sensor to the screed members) until the correct elevation reading is signaled.

Once the sensors have been set, the screeder apparatus may be moved away from the initial set up area without the levels being adjusted, as the sensors may track the laser beam and adjust to this working plane when activated by the operator through the remote control unit. This system gives added advantages as the screed will always .work to the correct plane even after the apparatus has been moved, relocated some distance away from the laser transmitter. Preferably, all forms of the invention may be combined into a superior screeding apparatus.

In a fourth form, the invention resides in a self propelled machine for use in construction, the apparatus including a. a mounting unit; b. propulsion means associated with said mounting unit for moving said mounting unit over the ground or support surface; c. a boom associated with said mounting unit; d. an attachment portion associated with an outer portion of said boom; e. at least one attachment devices adapted to engage with the attachment portion of the boom; and f. a control system including at least one computer and at least one sensor to provide information to the control system, the computer system having at least one set of preset parameters for use of each of the at least one

attachment device and the machine based upon the use to which the at least one attachment device is to be put.

Examples of some of the various attachment devices which may be used in conjunction with the machine of this embodiment may include: 1. Articulated Concrete Screeder with compaction system.

2. Pacific Equipment Handler ( Stressing Equipment Handler ).

3. Rock Drilling Rig with Concrete Coring capabilities.

4. Concrete Saw Cutter, Vertical, Horizontal or Inclined capabilities.

5. Man Lifter/Man Cage. 6. Forklift.

7. 4 In 1 Soil Bucket..

8. Post Hole Driller.

9. Ditch Digger.

The hydraulic systems for the machine are controlled by a control system associated with the machine, which will usually be or include at least one computer system. This computer system will identify what attachment has been fitted to the machine so as the hydraulic limitations of the machine can be adapted automatically to individual attachment. This is required as all attachments listed above as examples, are preferably different with different applications and uses, and therefore each attachment has its own set of limitations. These limitations are linked to the physical size of the machine and the capabilities of the machine. As each attachment is of different size, weight and has different functions from each other, they will cause the machine as a base platform, to react differently when attached and in use. The computer system is preferably adapted to identify which attachment has been fitted to the machine and therefore will change or stop different functions of the machine. This may assist in the prevention of overturning or accidents and therefore provides the over all machine/system with a high standard of safety. The computer will typically control all of the hydraulic systems for the machine and the attachment that is connected to the machine at the time. As soon as an attachment is connected, the computer system will immediately make all the required adjustments to the hydraulic system including in particular the operating

parameters of the machine and the attachment that govern its use whilst that attachment is attached. These adjustments preferably are presets which can not be changed or overridden by the operator at any time.

The computer system preferably controls the hydraulics by changing the pressure allowed to be used or even stopping a function before the machine reaches a point of no return or dangerous situation such as over turning or over loading. The computer system is preferably adapted to identify the length to which the boom is extended, at what angle the boom is oriented and the weight which is being lifted by the machine. From these inputs, the computer control system can calculate the bending moments and torque for example imposed on the machine. This will allow the computer control to limit or prevent actions before the machine and system parameters are exceeded. Therefore limitations will preferably have been preprogrammed into the computer system to provide the machine and complete system with separate limitation sets of operational parameters for each and all the various attachments that can be fitted.

Basically, the computer sensor and control system should allow a great number of attachment to be used with the same machine whilst maintaining a separate set of rules governing the operation of the machine with the different attachments, thereby maintaining a high standard of safety for all. The computer system will also preferably control the Articulated

Concrete Screeder with compaction system by using the information provided by the Laser Transmitter that is sent to the Laser Receiver which is fitted to the Screeder. The is information is then passed on to the Computer System and the computer can adjust the position of the screeder as required. The screeder apparatus will preferably be fully controlled by the computer system once the system is set in the fully automatic mode as described in the laser adjustment section.

The computer system is preferably pre-programmed and fitted to the machine in a water-tight container within the restraints of the machine's body and is typically not accessible to the owner or operator. This is to prevent tempering or overriding of the safety features that have been set for the complete system.

BRIEF DESCRIPTION OF THE DRAWINGS Various embodiments of the invention will be described with reference

to the following drawings, in which:

Figure 1 is a perspective view of a screeder apparatus according to a preferred embodiment of the present invention.

Figure 2 is a top elevation of the screeder apparatus illustrated in Figure 1.

Figure 3 is a side elevation of the screeder apparatus illustrated in Figure 1.

Figure 4 is a front elevation of the screeder apparatus illustrated in Figure 1. Figure 5 is a side elevation view of the screed means of the present invention showing the screeding of high slump materials.

Figure 6 is a side elevation view of the screed means of the present invention showing the screeding of low slump materials.

Figure 7 is a side elevation view of the screed means of the present invention showing the screeding of materials on an incline.

Figure 8 is a side elevation view of the multi-directional pivot connector according to a preferred embodiment of an aspect of the invention.

Figure 9 is a front elevation view of the multi-directional pivot connector illustrated in Figure 8. Figure 10 is a perspective view of a bucket attachment device according to an embodiment of the invention.

Figure 11 is a perspective view of a bucket attachment device according to another embodiment of the invention.

Figure 12 is a perspective view of a fork attachment device according to an embodiment of the invention.

Figure 13 is a perspective view of a cage device for lifting persons or equipment according to an embodiment of the invention.

Figure 14 is a perspective view of a rock-drill attachment device according to an embodiment of the invention. Figure 15 is a perspective view of a support frame attachment device according to an embodiment of the invention.

Figure 16 is a perspective view of an attachment assembly and central support assembly for a screeder attachment according to an embodiment of the

invention.

Figure 17 is a view from below of the central support assembly of the screeder attachment illustrated in Figure 16.

Figure 18 is a perspective view of a screeder device according to an alternative embodiment of the invention.

Figure 19 is a perspective view of a machine according to an alternative embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT In a particularly preferred embodiment, a screeder apparatus 10 to spread, distribute, smooth and/or level, placed and/or poured, uncured concrete, sand, gravel or like, loose spreadable materials is provided.

A preferred embodiment of the screeder apparatus 10 is illustrated particularly in Figures 1 to 4. The screeder apparatus 10 illustrated includes a mounting unit 11 comprising a chassis 12 and a main body 13. The chassis 12. is provided with powered wheels 14 for moving the screeder 10 over the ground or other support surface. The screeder 10 has a cantilevered boom 15 associated with the main body 13 of the mounting unit 11 and screed head 16 for spreading and/or smoothing the loose material, is associated with the boom 15. The screed head 16 includes at least a pair of screed members or bars 17 for contacting the loose material to be spread and/or smoothed, the screed members 17 being spaced apart in a screeding direction.

Facts and Figures.

Screed Bars 17 Length. = 4,500 mm

Mounting unit 11 Width. = 1,000 mm

Mounting unit 11 Length. = 1,500 mm Screeder Height (From Wheels) = 1,350 mm

Screeder Height (From Outriggers). = 1,550 mm

Outrigger Extension ( Maximum Width ). = 2,450 mm

Outrigger Extension ( Maximum Length ). = 2,750 mm

Boom 15 Length ( Retracted ). = 1,630 mm Boom 15 Length ( Extended, Maximum Reach Horizontal ) = 6,200 mm Boom Extension beyond the perimeter of the Main Body. = 4,650 mm Boom Height ( Extended Maximum Reach, Vertically ). = 7,345 mm Travel Speed in Forward ( Speed # 1 ) Metres per minute = 20 metres.

Travel Speed in Forward ( Speed # 2 ) Metres per minute = 75 metres. Travel Speed in Reverse ( Speed # 1 ) Metres per minute = 20 metres. Travel Speed in Reverse ( Speed # 2 ) Metres per minute = 75 metres. Approximate Screed Rate ( m 2 per hour ). = 250m 2 The chassis 12 is a sturdy steel construction unit that supports the weight of the entire screeder and all its mechanical components. The chassis 12 acts as a counterweight for the screeder head 16, keeping it stable and prevents overturning as it has a very low centre of gravity.

The chassis 12 is designed with four extendable outrigger assemblies 18 that are used as additional stabilising. These outriggers 18 also allow the chassis 12 to be fully supported while the wheels 14 are completely off the ground, as this may be required when operating the screeder 10 on uneven surfaces or inclined working areas.

The chassis 12 is supported by 8 pneumatic wheels 14, 4 located on each side of the chassis 12. The screeder 10 is a full time eight wheel drive unit utilizing a skid steer method. Accordingly, the wheels on one side of the chassis 12 can be stopped or be rotating in the opposite direction to the wheels 14 on the opposite side. This allows the screeder 10 to turn 360° within its own body length, therefore allowing it to turn in a much smaller working area than conventional steering systems such as turning systems for trucks and cars.

There are two hydraulic motors (not shown), one driving each set of four wheels. These motors are a two speed motor in each direction. The first speed is a low travel speed, approximately 20 metres per minute, used for steep inclines and while carrying heavy loads. The second speed is a faster traveling speed, approximately 75 metres per minute. The faster speed is used on flat open areas where the screeder 10 be needed to be moved over a large distance in a short period, while no loads are being earned.

The hydraulic motors are mounted at one end of the drive train fixed securely to the chassis 12. The hydraulic motors are operated independently to each other. The motors are controlled from the remote control unit (not shown) by an operator. An electric signal is sent from the remote control panel to the hydraulic solenoid for controlling the hydraulic drive motor. The solenoid will open or close depending on the signal received from the remote control unit and therefore stop the

wheels from rotating, or make the wheels rotate in the opposite direction.

The hydraulic motors for the wheels are fitted with an internal brake. This allows the screeder 10 to stop and work on steep inclines. The brake system is designed, to disengage only after the hydraulic oil pressure inside the motor has built up enough to support the load currently being supported by the braking system. The braking system requires pressure to release it. For example, if the main hydraulic oil lines were cut, damaged or removed, the brakes would still be fully engaged.

The hydraulic motors are powerful enough to drive the screeder 10 up or down an incline/decline angle of 22.5° in the forward or reverse directions. The chassis 12 is fitted with a slewing ring 19 (horizontal turntable) on the upper side at the centre of the chassis 12. This slewing ring 19 is the main connection point between the chassis 12 and the main body 13. The slewing ring 19 is fitted with an internal gear system which is fixed to the chassis 13 by high grade bolts. This is to prevent the gear system from moving or rotating at any time. The gear system becomes a permanent part of the chassis.

All the hydraulic and electrical lines for the screeder 10 are run through the centre of the slewing ring 19. These electrical and hydraulic lines are the main systems that are used for moving and controlling the chassis 12 and its outrigger assemblies 18. The main body 13 is where the main motor and all the main hydraulics and electric systems are based. This is the control centre of the screeder 10 where all the different input and feedback information is returned before activating and controlling the movements of the screeder 10 through the various hydraulic systems.

The main body 13 is constructed from sturdy steel like the chassis 12, as it also is designed to act as a counterweight for the screeder 10, providing it with further stability directly above the chassis 12, while providing the upper sections of the screeder with a strong and sturdy support system.

The main body 13 can rotate 360° in a horizontal plane on the chassis 12 through the slewing ring 19. The main body 13 has the second half of the slewing ring 19 fixed to the centre of it on the underside. When the slewing ring 19 is complete in its assembly between the chassis 12 and main body 13, then the individual sections operate as a single assembly. These units then cannot be separated, even if the complete assembly was turned upside down.

The slewing ring 19 is constructed from high grade steel with a special surface treatment where a high grade teflon plate is fitted. The teflon plate can turn freely between the upper and lower sections of the slewing ring 19, which are both chrome plated to reduce friction and wear to the teflon plate. This design allows large loads/forces to be transferred through the slewing ring 19 and distributed into the wheels 14 or outriggers 18 supported on the ground at any stage during the 360° rotating of the main body 13, while maintaining a smooth almost friction-free turning movement. This design reduces the clearances required with standard slewing ring 19 designs as it does not require the use of bearings at all. The slewing ring 19 is capable of full rotation at any time without decreasing the stability of the screeder at any time.

The slewing ring 19 is fitted with a hydraulic motor which controls the rotation of the main body 13 on the slewing ring 19. The hydraulic motor brakes system is designed to disengage only after the hydraulic oil pressure inside the motor has built up enough to support the load currently being supported by the braking system. The braking system requires pressure to release it. For example, if the main hydraulic oil lines were cut, damaged or removed the brakes would still be fully engaged preventing the main body from rotating in either direction.

The main body 13 contains the main power source for the screeder 10 (either a petrol engine or an electric motor) which is used to drive the main hydraulic pump(s). The hydraulic pump(s) are connected to a manifold block and electronic solenoids. The solenoids control in which direction/line the hydraulic oil is allowed to flow, which will move cylinders or hydraulic motors in a forward of reverse direction. All excess oil is returned to an oil tank 80 which is fitted to the main body 13. All the hydraulic oil is recirculated through the system and brought back to the oil storage tank on the main body 13.

The screeder 10 has been designed to allow two different engine types. The first engine type is a petrol drive motor which is used to drive/power the hydraulic pump(s). The second engine type is an electric motor which is used to power the hydraulic pump(s). Both of these motors' engines operate approximately between 15 to 20 Hp.

Both the electric and petrol drive units will have equal capacities and capabilities, therefore it is only a matter of the surrounding environmental issues that

may determine the motor requirements.

At a rear section of the main body 13, there are a pair of heavily constructed support arms 20 which are the main anchoring and stabilizing points for the base of the boom 15. These support arms 20 are designed to take loads in all directions, allowing the strength of the screeder 10 to be fully maintained during any operation.

The support arms 20 also act as a major protection frame for the motor (power source), hydraulic pump(s) and all the operational systems supported and installed onto and around the main body 13. All the actions of the screeder 10 are controlled primarily from the operator's control panel. This is a small sturdily constructed water-proof box, which provides all the information to the electrical, hydraulic and power sources for the entire machine. Some of the operation may be performed under automatic control using feedback control loops, but only if the operator enables automatic control. If this does not occur then the movement and operation of the screeder 10 is directly controlled by the remote control unit in the hands of the operator.

The chassis 12 and main body 13 are designed to work as a single unit. Each of the these sections has been designed to withstand the hard treatment common to the building site. With heavy construction reinforcing the framework and providing additional strength to the completed system, the screeder 10 is ready for any site and the hard working conditions.

The boom 15 of the screeder 10 is illustrated in Figures 1 to 4 and has an articulated tip portion best illustrated in Figures 5 to 7.

The boom 15 is broken into five individual stages. The first stage 21 (main stage) in permanently connected to the main body 13 though the support arms 20 at the rear of the main body 13. This connection is by way of a large pin which allows the boom 15 to rotate in a vertical direction approximately 90°. There are two hydraulic cylinders 22 connecting the front section of the first boom stage 21 to the main body 13 of the screeder 10. These hydraulic cylinders 22 cause the boom 15. to rotate upward and downwards as controlled by the operator. The two cylinders 22 are braced together in sturdy steel frame to increase the strength and rigidity of the overall framework. This additional bracing reduces any lateral movements of the boom 15 during slewing operations with a fully extended boom 15 in a high elevation position,

for example, when the boom 15 is rotated upwards to the maximum allowable angle.

Stages 1, 2, 3 and 4 of the boom 15 are approximately 1640mm long each. Stage 5 of the boom 15, which is the articulated tip section, is approximately 900mm long. When all four stages are fully retracted and the articulated section is folded back underneath the first boom stage 21 (closed position), the boom 15 is approximately 1630mm long. When all four stages are fully extended and the articulated section is straightened to be in the same line as the first boom stage 21 (opened position), the boom 15 is approximately 6200mm long. The second, third and fourth stages 23, 24, 25 are fully retractable stages. This means that the boom 15 can extend and retract within itself. This is controlled by hydraulic cylinders inside the boom 15 which extends and retracts as signaled by the operator.

All of the four retractable sections of the boom 15 slide on a specially designed high grade teflon plate, similar to the slewing ring 19 between the chassis 12 and main body 13. The teflon plates in the boom 15 provide smooth movements during the retraction and extension phases while reducing clearances to a minimum within the boom stages. This design allows for less self deflection and provides a stronger and smoother joint throughout the boom operations. . The fifth section 26 of the boom 15 is the articulated section of the boom 15. This section of the boom 15, while not retractable like the first four stages, still provides a similar amount of flexibility. This section of the boom 15 can rotate in the vertical plane to allow the screeder 10 to work in a different working plane compared to the plane that it is set up on. It is fitted with a pair of hydraulic cylinders 22, one to rotate the fifth boom stage 26 about the fourth boom stage 25 and a second to rotate the pivot head 31.

At the end of the fifth boom stage 26 there is a connection shoe 27 which is designed to provide fast connection of a different variety of attachments. For a change in attachments, it requires the removal of a pair of pins within the shoe mechanism. The shoe, can also rotate in the same vertical plane as the fifth boom stage 26, and therefore, in conjunction with the fifth boom stage 26, the connection shoe 27 provides an increasing amount of flexibility and movements. The connection shoe 27 is a semi-permanent fixture to the boom 15, however it may be removed if

required. There is a simple two pin connection between the fifth boom stage 26 and the connection shoe 27.

All the clearances and tolerances between all the boom stages from the main body 13 to the connection shoe 27 are extremely small. This is to prevent any unwanted movements during the operations of the screeder 10 at any stage and to reinforce the connection points. Boom Extension and Retraction

The boom 15 can only be extended in manual operations but it may be retracted in either manual or the automatic setting. This will depend on the operator requirements at the time and the site conditions at hand.

The manual operation for retracting the boom 15 means that the operator must constantly activate the switch in the retract position for the boom 15 to continually retract.

The automatic operation is controlled by the operator from the remote and is only activated when the operator sets the switch to automatic retract. When the switch is set in this automatic position, the boom 15 will continuously retract until it is fully closed and has activated the automatic stop switch located inside the boom structure.

The boom 15 can rotate in the vertical plane from just below a horizontal level (with respect to the mounting unit 11) through to almost vertical This gives the boom 15 a range of approximately 90°, allowing it to reach some 7,000mm above the chassis 12.

The boom speed may be varied in the retraction or extension operation by the operator. This can be done by simply turning a speed dial mounted on the screeder (main body 13). This operation can be adjusted in the automatic or manual operation. The speed control simply adjusts the hydraulic oil pressure needed to activate the cylinder inside the boom sections. Speed adjustment also acts as a safety device as the system operates on pressure. Therefore, if the screed members 17 were to clash then the operation would stop automatically once the maximum , allowable pressure had been reached, that is, only enough pressure to retract the boom 15 while ' loaded with concrete and an additional 30 Kg of load. ( Example Only ) To move the Screed members 17 loaded with wet concrete. = 80 Kg of pressure.

Theoretical Increase in concrete load (Varies continually) = 30 Kg of Pressure. Total maximum working pressure set for retraction. = 110 Kg of Pressure.

The screed members 17 are eacri high grade aluminum hollow sections fixed together via stiffener plates 28 spaced along the length of these members 17. These stiffener plates 28 keep the members 17 aligned at all times causing the members 17 to act as a single system. The stiffener plates 28 do not extend to the bottom edge of the screed members 17, preventing any marking to the finished surface of the material being screeded, such as wet concrete. Each screed member 17 is approximately 4,500mm long and the members 17 are set at approximately 300mm apart, centre to centre, in the longitudinal direction.

There is a sliding rail 29 fixed along the top surface of each screed member 17. Each sliding rail 29 passes through sliding shoes 30 on the pivot head 31 illustrated in Figures 8 and 9. The slide surfaces of the sliding rails 29 are coated with a hardened . chrome surface. This surface protects the sliding rails 29 from contaminates such as wet concrete and surface corrosion, while providing a low friction resistance when sliding through the sliding shoe 30. The sliding rails 29 taper downwardly and inwardly along the length of the rails 29 to assist in the tightness of the connection between the sliding shoes 30 and the sliding rails 29. The tapering of the rails 29 also assists in the controlling of the screed members 17 in the longitudinal rotation of the screed members 17, preventing movement in these directions.

The screed members 17 are slid from left to right by a hydraulic motor attached to the pivot head 31 driving the screed members 17 in the required direction by a gear track fixed to the edge of one sliding rail 29. The hydraulic motor is designed with a braking system to prevent any self movement. The hydraulic motor brakes system is designed to disengage only after the hydraulic oil pressure inside the motor has built up enough pressure to support the load currently being supported by the braking system.

The screed members 17 are suspended from the pivot head 31 by the sliding shoes 30 and rails 29 during the screeding operations. To assist in the finishing of the surface of the material being levelled, or screeded, the screed member system is fitted with a vibration unit. The vibration unit is driven by a hydraulic motor fitted in between the screed members 17. The motor then drives a centre shaft that is. fitted with small weights set at various locations to provide the correct amount of

vibration for the required material being screeded. The spinning of the shaft with weights is the cause of the vibration being directed into the surface of the material being screeded providing the desired finish. The speed of the hydraulic motor may be varied to adjust the amount of vibration at any given time. The dual screed member 17 design is designed to give an operator more flexibility when leveling and finishing the materials being placed such as wet concrete. The dual screed member 17 can be rotated in the longitudinal direction, depending on the slump of the concrete being placed.

During the screeding of the materials, such as wet concrete, the first screed member 32 (Master Pole) will push the concrete in front of it like a blade. The concrete on the front surface/side of the Master Pole 32 should be approximately

20mm to 60mm high than the required finished l,evel of the concrete. The height will depend on the slump of the concrete being placed at the time, and the gradient in which the screeder is working to (up an incline or down a slope). The second screed member 33 (Slave Pole) will only push 5mm to 20mm of concrete in front of it, as it will complete the finishing of the concrete surface to the required level.

The dual screed members allow the concrete to be finished off smoothly and accurately as there are two members passing over the same area of concrete. The master screed member 32 compacts and removes approximately 90% of the un-needed concrete leaving an already level surface for the slave screed member 33.

The slave screed member 33 removes the final amounts of un-needed concrete while re-compacting the concrete as it passes, leaving a smooth and fully compacted concrete behind it. Therefore, the finishing is constant and accurate through the entire surface.

The screed members 17 may be slid from side to side to allow the screed members 17 to pass permanent obstructions protruding above the finished surface levels. This adjustment can be carried out with stopping the retracting actions of the boom 15 therefore the concrete surface finish is maintained and constant.

The rotation of the screed members 17 about the pivot head 31 during the retraction operation of the boom 15 allows the screed members 17 to reach further and work around curve, rather than the conventional straight line method, which can not always be achieved due to differences from one site to another.

The dual screed members 17 also provide an advantage when screeding from a horizontal plane into an inclined plane. Tlie master screed member 32 can be

rotated upwards as it moves up the incline while the slave screed member 33 maintains the required levels for the horizontal plane. Another advantage of the dual screed members 17 is that the operator can see at all times how much concrete is being pushed by both the Master 32 and the Slave 33 screed members, therefore avoiding the possibility of leaving low points in the final surface level as may be the case with a single screeding member system.

Figure 5 illustrates the use of the dual screed members 17 for screeding "high slump concrete". If the concrete slump is high, i.e 180mm, then this means that the concrete is soft and will not support itself as concrete with a "low slump" will. When leveling this type of concrete, the screed members 17 will be rotated about an axis substantially parallel to- the required finished level of concrete causing the first screed member 32 (Master Pole) to be lower then the second screed member 33 (Slave Pole) by approximately 15mm. This will be required as the vibration of the screed members 17 will cause the concrete to self-level. This means that the concrete will form an average height between the top level of concrete in front of the Master Pole 32 (+40mm) and the bottom edge of the Slave Pole 33. Therefore the concrete will average at approximately +20mm with the Slave Pole 33 pushing the concrete forward. The concrete will then come to the final and correct level as required.

Figure 6 illustrates the use of the dual screed members for screeding "low slump concrete". If the concrete slump is low, that is approximately 80mm, then this means that the concrete is stiff and is self-supporting. Therefore when levelling this type of concrete, the screed members 17 will be working on the same surface plane as the concrete finished level. This is because the concrete is stiff and the movement of the concrete is less than concrete with a high slump as described with reference to Figure 5.

Figure 7 illustrates the use of the dual screed members for screeding concrete on an angled surface. When the screeder 10 is being used on an incline or decline, then the rotation of the screed members 17 in the longitudinal direction can be adjusted accordingly to allow for the slump of the concrete being placed as described with reference to Figures 5 and 6 and to suit the inclination that the screeder is working to.

The screeder 10 is fitted with a special rotating pivot head 31 that pivots in multiple directions simultaneously, while rotating on the specified plane.

The pivot head 31 has a connection shoe 27 to attach to the connection shoe 27 of the fifth boom stage 26. This provides the screed members 17 with increased flexibility, allowing it to perform on unique angles, allowing it to work almost every surface, at any time without hindering the progress of the work in any way. The pivot head 31 is able to rotate in a first plane up to 360° and is provided with a connection shoe 27. The rotation system is like the slewing ring 19 between the chassis 12 and the main body 13. This slewing ring 19 is fitted with a hydraulic motor that controls the rotating at all times and prevents the screed members 17 from moving off the set alignment. The hydraulic motor brake system is designed to disengage only after the hydraulic oil pressure inside the motor has built up enough pressure to support the load currently being supported by the braking system. The braking system need pressure to release it, so it is a very safe system.

The universal pivot head 31 is designed to provide the screed members 17 with full movement in the longitudinal and transverse direction at the same time while not hindering the rotation of the screed members 17. This design allows the screed members 17 to be adjusted in all three directions simultaneously without stopping the screeding operation. The design is a simplistic design as it needs to be able to withstand the knocks, bumps and contamination from the materials being screeded, such as wet concrete and slurries. The pivot head 31 provides a strong connection between the screed members 17 and the connection shoe 27 therefore reducing unwanted movement while maintaining flexibility within the complete system.

The universal pivot head 31 has a circular frame where four hydraulic cylinders 34 are connected for controlling the rotating in the transverse and longitudinal directions through the pivot head 31. These four hydraulic cylinders 34 are connected from the base of a rotation table 35 associated with the slewing ring 19 to a circular frame 36 mounting the sliding shoes 30. These hydraulic cylinders 34 rotate with the screed members 17 ensuring that any adjustment is made on the correct plane to the screed members 17 and to keep all the adjustment very accurate at all times throughout the operation.

At the base of the pivot head 31, there is a circular frame 36 which supports a pair sliding shoes 30. These sliding shoes 30 allow the screed members 17 to slide in the transverse direction, approximately 1000mm in each direction. This

system allows the screed members 17 to be slid left to right during the screeding operation to manoeuvre the screed members 17 around permanent fixtures protruding above the finished surface level. This sliding movement can be carried out while the screeder is in full operation and will not affect any other operations being carried out. The sliding shoes 30 are designed with a high grade Teflon plate inside to provide a smooth, low resistant sliding operation while maintaining a high tolerance within the connection of theses sliding shoes 30, preventing movement in the longitudinal or horizontal planes. The inner surfaces of the sliding shoes 30 are coated with a hardened chrome protection layer. This chrome layer along with the high grade Teflon plated provides low friction while reducing the clearances between the separate components. Laser Leveling System.

The screed members 17 may be adjusted at any time during the screeding operations. This adjustment is carried out by the hydraulic system, which is controlled by small electrical signals provided from the operators control box (manual operation) or from the signal being received from a plurality of laser sensors 37 that are transferred to the control board. Manual Controls

Using the control box (remote control unit), the operator can control the position and orientation of the screed members 17 by simply turning a switch from the OFF position too the UP or DOWN position, depending on the movement required. The switch will automatically return to the OFF position once released, therefore the switch must be held on to continue the adjustment further.

When the switch is activated, a small electrical current is sent from the switch to the relevant hydraulic solenoid, causing the solenoid to activate accordingly. When the solenoid is activated, it will allow the hydraulic oil to pass through the system into the cylinder 34 causing the cylinder 34 to extend or retract, depending on which direction the control switch was turned (UP or DOWN). If the operator wants to move the screed members 17 for an extended amount then the switch must be held ' in the required position until the movement is completed. Automatic Controls

The automatic control board when activated, can control all the movements and orientation of the screed members 17 required for leveling and retraction of the boom sections back towards the screeder main body 13.

The automatic controlling system is still controlled by the operator from the remote control unit. The operator simply turns the operations switch from MANUAL to AUTOMATIC. This will then allow the control board to activate the hydraulic cylinders 34 as required.

The automatic control board receives signals from the laser sensors 37 mounted along the 4500mm length of the screed members 17. The signal from these sensors 37 is then relayed to the control board as a small electrical current which then activates the hydraulic solenoid.

The three laser sensors 37 are controlled by a laser beam that is projected from a stationary laser transmitter (not shown) located remotely from the screeder 10. The laser transmitter projects a laser beam parallel to the surface of the material being screeded, such as concrete. The laser sensor 37 reads its elevation in accordance with the laser beam and then sends a small electrical signal back to the control board. This signal then activates the required solenoid allowing the screed members 17 to be adjusted so as it is constantly working at the same plane as the laser beam being transmitted. There are three signals that are received by the laser sensor 37, namely 1. Elevation too Low, 2. Elevation too High, 3. Correct Elevation. When the laser sensor 37 signals the control board (for example, 3. Correct Elevation) the solenoids will lock off, holding the screed members 17 at this elevation until another signal is received from the sensors 37. The sensors 37 take reading to the laser beam at an approximate rate of 8 readings per 1 second. The average of these readings is calculated and then this averaged signal is sent to the control board. With this amount of constant monitoring the screed members 17 are constantly adjusted automatically resulting is a uniform surface finish.

There are two sensors 37 attached to the screed members 17, one at each end, and a third sensor is positioned at the centre on the pivot head 31. The two sensors, one at each end, control the screed members 17 in the transverse elevations, while the third sensor 37 controls the longitudinal elevation. This allows the screeder 10 to work in two planes simultaneously.

The sensors 37 are set just before the materials are to be placed, such as wet concrete. To set the sensors 37, the screed members 17 must be set at the correct elevation and then the laser transmitter is initialised. It is a simple matter of sliding the sensors 37 up or down the poles used to secure the sensor to the screed members 17 until the correct elevation reading is signaled.

Once the sensors 37 have been set, the screeder 10 may be moved away from the initial set up area without any worry of the levels being adjusted, as the sensors 37 will now track the laser beam and adjust to this working plane when activated by the operator through the remote control unit. This system gives added advantages as the screed will always work to the same, correct plane even after the screeder has been moved, relocated some distance away from the laser transmitter.

In the present specification and claims (if any), the word "comprising" and its derivatives including "comprises" and "comprise" include each of the stated integers but does not exclude the inclusion of one or more further integers. Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more combinations.