Patent Description:
Sheet materials can be difficult to handle, particularly in respect of larger sheets and/or sheets made of materials with a high density, which can be particularly heavy. Sheet materials include glass panes, insulated glass units ("IGUs"), framed windows / IGUs, plasterboard, timber boards (including engineered timber materials), doors, fibre cement sheet, and the like. Current architectural trends favour large, uninterrupted glazing that has a low thermal conductivity. Consequently, large and heavy individual glass sheets, and IGUs are commonly used in new buildings and in renovations.

Manual handling of sheet materials is undesirable for health and safety reasons. To limit the manual lifting of sheet materials for transportation and installation, it is known to use devices, such as motorized and hand-operated trolleys / carts. In the glazing industry, these devices can reduce the number of people required to lift, transport and install glass panes, etc. Hand-operated devices have the advantage of being light weight, and can enable a single user at a job site to transport and install glass panes with a mass in excess of <NUM>, and/or have a long edge that is in excess of <NUM>.

Installation of sheet material, such as glass panes and IGUs, can require transportation of the material from a vehicle or a store, to the installation location. Once at the installation location, there can be need for relatively fine movement of the sheet material (sometimes with millimetre precision) to position the sheet material in the ultimate position within a frame or mount. By way of example, glass sheet that is installed in a floor-to-ceiling application is "oversize" relative to the opening, because the supporting frame structures are concealed by the floor and ceiling. The glass sheet is installed by positioning one edge in the frame, and then slowly and carefully manipulating the glass sheet fully into the frame. Stability of a glass sheet during transport to the installation location is important for the safety of the operator / installer, and for minimizing the likelihood of damage to property, including the glass sheet.

<CIT> discloses a device for use in lifting, transporting and installing sheet material according to the preamble of claim <NUM>.

There is a need to address the above, and/or at least provide a useful alternative.

There is provided a device for use in lifting, transporting and installing sheet material, the device comprising:.

Preferably, the actuator is operable to rotate the mast to a forward angular position relative to the base in which the upper end of the mast is forward of the rotational axis. Alternatively or additionally, the actuator is operable to rotate the mast to a forward angular position relative to the base in which the upper end of the mast is forward of the front wheels.

Preferably, the actuator is operable to rotate the mast to a rearward angular position relative to the base in which the upper end of the mast is rearward of the rotational axis. Alternatively or additionally, the actuator is operable to rotate the mast to the forward angular position relative to the base in which the upper end of the mast is forward of the front wheels.

In some embodiments, when the mast is in the forward angular position the bottom of the traversable portion of the mast is forward of the rotational axis. In some embodiments, when the mast is in the rearward angular position the bottom of the traversable portion of the mast is rearward of the rotational axis.

In at least some embodiments, the device has a forward limit stop to limit the angular position of the mast relative to the base to a forwardmost angular position. In some embodiments, when the mast is in the forward angular position, the bottom of the traversable portion of the mast is forward of the forward limit stop.

Alternatively or additionally, the device has a rearward limit stop to limit the angular position of the mast relative to the base to a rearmost angular position. In some embodiments, when the mast is in the rearmost angular position the bottom of the traversable portion of the mast is rearward of the rearward limit stop.

Preferably, the forward and/or rearward limit stops provide a physical barrier to rotation.

The device can include component parts and/or weights that are disposed over and/or rearward of the rear wheels, whereby, when:.

the centre of mass of the device and the predetermined mass is rearward of the front wheel set.

Preferably, the device includes a handle for a user to grasp when moving the device across a surface, wherein the handle is disposed over and/or rearward of the rear wheels. In at least some embodiments, the handle is rotatable with the rear wheels.

Preferably, the device further comprises one or more mounts at the rear of the device, whereby weights are mountable onto the mounts to provide additional mass to counterbalance sheet material that is supported on the supporting head. Preferably, each mount has a weight retaining member that inhibits removal of weights from the respective mount.

In certain embodiments, the device includes one or more drive motors that are arranged to drive at least one wheel of the device. Preferably, the drive motors are disposed in the rear portion of the device, and are arranged to drive the rear wheels of the device. Preferably, the device includes a battery to provide electrical power to the drive motors. In some embodiments, the rear portion of the device includes a housing, wherein the battery, drive motors and an electrical circuit that interconnects the battery and drive motors are contained within the housing.

In embodiments in which the device includes a battery, the actuator can be an electromechanical actuator that is powered by the battery. In at least some embodiments, the actuator is a linear actuator.

The device can further comprise an articulated coupling between the front and rear wheels that enables the rotational axis of the rear wheels to rotate within a general horizontal plane and about an articulation axis relative to the front wheels to thereby steer the device. Preferably, the articulation axis is transverse to the rotational axis of the rear wheels. In certain embodiments, the articulation axis of the articulated coupling intersects the rotational axis of the rear wheels.

In some embodiments, the base comprises a frame with a linkage that extends between the front and rear portions of the device, whereby the length of the linkage is adjustable to thereby adjust the wheelbase of the device. Preferably, the articulated coupling is disposed at the rear of the frame.

In embodiments in which the device includes drive motors that are arranged to drive the rear wheels of the device, and the device comprises a rear drive unit that is connected to the frame by the articulated coupling. In such embodiments, the mounts for the weights are preferably part of the rear drive unit.

The frame can further comprise a swivel that enables the articulation axis to rotate relative to the common axis of the front wheels. Preferably, the device has swivel limit stops that restrict the rotational range of the articulation axis. In some embodiments, the swivel limit stops restrict the rotational range to <NUM>°. Preferably, the swivel limit stops restrict the rotational range to approximately <NUM>°.

In some embodiments, the base includes a pivot section that is pivotally connected to the frame, the pivot section including a mast step to which the mast is connected, and wherein the actuator is a linear actuator that is connected at one end to the frame, and at the opposing end to the pivot section.

Preferably, the device is arranged with the lifting mechanism connected to the base so as to rotate with the mast about the rotational axis. In embodiments in which the front of the base includes the pivot section, the pivot section can include an arm on which a winch of the lifting mechanism is connectable or is connected. The arm can have a lower end that is connected to the mast step.

The device can comprise at least one axle on which the front wheels are mounted. In some embodiments, the front wheels are connected to the pivot section so that the common axis is rotatable so as to rotate with the mast about the rotational axis.

In some alternative embodiments, the actuator is a linear actuator that extends between the frame, and the mast.

In certain embodiments, the actuator includes a screw shaft that is rotatable to rotate the mast, a fixed nut that is connected to the base, and a drive input that is rotationally fixed to the screw shaft, whereby a user can rotate the drive input to cause the threaded shaft to rotate. In one form the drive input can be a socket to which a tool is attachable. In some alternative forms the drive input can be manually rotatable, and is one or more of: a knob, a wheel and a handle, that is secured to the threaded shaft.

In some embodiments, the supporting head has two spaced apart support subassemblies that are interconnected by a cross bar; and the device further comprises a coupling assembly that couples the supporting head to the carriage,.

Preferably, the second connector includes one or more spring-biased pins that are mounted on the cross bar mounting portion, and are arranged with a shaft that is to project through aligned apertures in the cross bar and cross bar mounting portion when the supporting head is in the first position.

There is also disclosed a device for use in lifting, transporting and installing sheet material, the device comprising:.

Thus, the second connector can release the supporting head such that the supporting head can rotate on the first connector.

In some embodiments, the mast is connected to the base such that the mast is rotatable relative to the base about a rotational axis, the rotational axis being parallel to the common axis, and the device further comprises an actuator that is operable to change the angular position of the mast relative to the base.

In order that the invention may be more easily understood, an embodiment will now be described, by way of example only, with reference to the accompanying drawings, in which:.

<FIG> show a device <NUM> according to a first embodiment of the present invention. The device <NUM> is intended for use in lifting, transporting and installing sheet material.

The device <NUM> includes a base <NUM>, and rear wheels 14a and front wheels 14b on which the base <NUM> is supported. The wheels 14a, 14b enable the base portion <NUM>, and thus the device <NUM>, to be moved across a surface. As described in further detail in reference to <FIG> and <FIG>, the rear wheels 14a are connected to the rear of the device <NUM> in a manner that permits steering.

The front wheels 14b, which are connected to the front of the base <NUM>, include a wheel to each side of the device <NUM>. The wheels of the front wheel set being rotatable about a common axis CX. In this example, the device <NUM> has a single wheel on each side of the device <NUM>, but in some other embodiments there may be two or more front wheels on each side of the device <NUM>. In this particular embodiment, the front wheels 14b are mounted on an axle <NUM> so as to rotate independently of each other.

The device <NUM> includes a mast <NUM> that extends upwardly from the base portion <NUM>. The base <NUM> includes a sleeve <NUM>, into which the lower end of the mast <NUM> is located and secured.

A supporting head <NUM> that is configured to support sheet material is mounted on a carriage <NUM>. The carriage <NUM> is in engagement with the mast <NUM> in a manner that enables the carriage <NUM> to be displaceable along the mast <NUM>, and also be guided by the mast <NUM>. In this particular embodiment, the supporting head <NUM> has four vacuum grips <NUM> at opposing ends of a cross bar <NUM>.

The base <NUM> includes a frame that interconnects the rear and front wheels 14a, 14b, and a handle <NUM> that is positioned at the rear of the device <NUM>, relative to the wheels 14a, 14b. A user can grasp the handle <NUM> to manipulate and move the device <NUM>. The direction from the handle <NUM> through the mast <NUM> defines a forward direction for the device <NUM>.

The device <NUM> also has a lifting mechanism to vertically support the carriage <NUM> along the mast <NUM>. In this particular embodiment, the lifting mechanism including a winch unit <NUM> with a winch <NUM>, and a cable <NUM> that is connected to the winch <NUM>. The lifting mechanism and carriage <NUM> are substantially similar to those of the devices described and illustrated in International (Patent) Publication No. <CIT> (entitled "Sheet Material Transport and Lifting Device"), filed in the name of Quantum Workhealth Programmes Pty Ltd).

The front of the base <NUM> includes a pivot section <NUM> that is pivotally connected to the frame, as shown most clearly in <FIG>. In this example, the frame includes a front linkage section <NUM>, and a pair of brackets <NUM> that are connected to the forward linkage section <NUM>. As is shown in <FIG>, <FIG> and <FIG>, the pivot section <NUM> is pivotally connected to the brackets <NUM>, in this example by a bolt <NUM>, so as to be rotatable about a rotational axis RX. The rotational axis RX is parallel to the common axis CX, as will be evident from <FIG>, <FIG> and <FIG>.

The pivot section <NUM> includes a mast step, which in this embodiment is in the form of the sleeve <NUM>, to which the mast is connected, and an arm <NUM> to which the winch unit <NUM> is releasably connected, in the manner described and illustrated in <CIT>. By virtue of the pivotable connection of the pivot section <NUM> to the frame, the mast <NUM> is rotatable relative to the base <NUM> about the rotational axis RX.

The device <NUM> includes an actuator <NUM> that is operable to change the angular position of the mast <NUM> relative to the base <NUM>. <FIG> shows the device <NUM> with the mast <NUM> in its rearmost angular position. In this particular embodiment, when mast <NUM> in its rearmost angular position, the mast <NUM> is an angle of approximately <NUM>° to <NUM>° to vertical, as indicated by angle α in <FIG> shows the device <NUM> with the mast <NUM> in its forwardmost angular position. In this particular embodiment, when mast <NUM> in its forwardmost angular position, the mast <NUM> is an angle of approximately <NUM>° to <NUM>° to vertical, as indicated by angle β in <FIG>.

In <FIG>, the device <NUM> is illustrated with a glass pane G supported on the vacuum grips <NUM>. The ability of the device <NUM> to rotate the mast <NUM> about the rotational axis RX as illustrated in <FIG> contributes to the usability of the device <NUM> during transport and installation of the pane G. To this end, when the mast <NUM> is placed in a rearward angular position, the centre of gravity of the pane G is closer to the centre of gravity of the device <NUM>. This has the benefit of contributing to the stability of the device. A prototype example of a device <NUM> according to this embodiment has been able to lift a glass pane of approximately <NUM> (approximately <NUM> pounds), which exceeded the weight of the prototype device. Where the weight of the sheet material exceeds the self weight of the device, the stability of the device and sheet material can be compromised.

The actuator <NUM> is operable to rotate the mast <NUM> to a forward angular position relative to the base <NUM> in which the upper end of the mast <NUM> is forward of the rotational axis RX. In this particular embodiment, the actuator <NUM> is also operable to rotate the mast <NUM> to a forward angular position relative to the base <NUM> in which the upper end of the mast <NUM> is forward of the front wheels 14b.

In contrast, when the mast <NUM> is placed in a forward angular position, the centre of gravity of the pane G is comparatively further from the centre of gravity of the device <NUM>. However, in some instances, it is necessary to install a glass sheet in front of the device <NUM>. The ability to position the mast <NUM> in a forward angular position has the advantage of being able to install sheet material in a generally vertical orientation in front of the front wheels 14b.

In addition, the winch unit <NUM> of the device <NUM> can be operated to move the carriage <NUM>, and thus the supporting head <NUM>, in a longitudinal direction with respect to the mast <NUM>, along a traversable portion of the mast <NUM>. In this particular embodiment, the traversable portion of the mast <NUM> is the portion that is between the sleeve <NUM>, and the mast head bracket <NUM>. This operation of the device <NUM> is substantially similar to that described and illustrated in detail in <CIT>.

In this particular embodiment, the actuator <NUM> is able to move the mast <NUM>, and also to retain the mast <NUM> in a desired position between the forwardmost and rearmost angular positions. Further, the actuator <NUM> is an electromechanical linear actuator that is powered by a battery of the device <NUM>. As shown in <FIG> and <FIG>, the actuator <NUM> is connected at a first end to the front linkage section <NUM>, and at the second end to the pivot section <NUM>. In particular, the second end of the actuator <NUM> is connected to the arm <NUM>. In this way, as the actuator <NUM> extends, the mast <NUM> is rotated about the rotational axis RX towards the forwardmost angular position.

The device <NUM> has a forward limit stop to limit the angular position of the mast relative to the base to the forwardmost angular position. In this particular embodiment, the forward limit stop is provided by a bolt <NUM> that extends between the brackets <NUM> and front of the sleeve <NUM>. As the mast <NUM> is moved to the forwardmost angular position, the sleeve <NUM> abuts the bolt <NUM>, which prevents the sleeve <NUM>, and thus the pivot section and mast <NUM>, from progressing further in the forward direction.

The device <NUM> also has a rearward limit stop to limit the angular position of the mast relative to the base to the rearmost angular position. In this particular embodiment, the rearward limit stop is provided by a shoulder <NUM> on the outer casing of the actuator <NUM>. As the mast <NUM> is moved to the rearmost angular position, by the actuator retracting the ram into the outer casing, the arm <NUM> abuts the shoulder <NUM>, which prevents the arm <NUM>, and thus the pivot section and mast <NUM>, from progressing further in the rearward direction.

In this embodiment, the rear wheels 14a are part of a rear drive unit <NUM> of the device <NUM>. The rear drive unit <NUM> includes an outer housing <NUM>, within which the device <NUM> has electric drive motors (not shown) that are arranged to drive the rear wheels of the device <NUM>, a battery (also not shown) to provide electrical power to the drive motors and the motor of the actuator <NUM>, and an electrical circuit (also not shown) that interconnects the electrical components of the device <NUM>, including the actuator <NUM>. The rear wheels 14a are arranged to rotate about a rear wheel axis WX.

The rear drive unit <NUM> has a control panel <NUM> that has controls with which a user of the device <NUM> can operate the device <NUM>, and in particular to activate the actuator <NUM>. As shown in the <FIG>, <FIG> and <FIG>, the handle <NUM> is part of the rear drive unit <NUM>. In this embodiment, the control panel <NUM> is immediately beneath and in front of the handle <NUM>. The device <NUM> has control levers (not shown) that are mounted on the handle <NUM>, with which the user operates the drive motors to drive the rear wheels 14a of the device <NUM> in the forward or reverse direction, as desired.

The rear drive unit <NUM> includes a set of mounts <NUM> (shown in <FIG>). Weights <NUM> are mountable onto the mounts <NUM> to provide additional mass to counterbalance sheet material that supported on the supporting head <NUM>. In this embodiment, the mounts <NUM> are arranged to support the weights <NUM> in two groups. In this way, the rear drive unit <NUM> can be evenly weighted over the two rear wheels 14a. In this particular example, there are four weights <NUM> in each group. Each mount has a weight retaining member (not shown) that inhibits removal of weights <NUM> from the respective mount. Accordingly, in the event that the device <NUM> moves across a laterally inclined surface, the likelihood of the weights <NUM> unintentionally coming off the mounts <NUM> is reduced.

As will be appreciated, the weight of the rear drive unit <NUM>, together with any weights <NUM> that are mounted on the rear drive unit <NUM>, provide counterbalance to the weight of sheet material that is supported on the supporting head <NUM>. As will be appreciated, the weight of the sheet material, together with combined weights of the mast <NUM>, supporting head <NUM>, pivot section <NUM>, and lifting mechanism, provide a torque that is centred on the contact of the front wheels 14b with the ground surface. Where that torque acts in a direction to lift the rear wheels 14a, the counterbalance described above acts to stabilize the device <NUM>.

Further, when the mast <NUM> is in its forwardmost angular position, the carriage <NUM> is at the top of the traversable portion of the mast <NUM>, and sheet material of a predetermined mass and/or geometry is supported on the supporting head <NUM>, the centre of mass of the device and the predetermined mass is rearward of the front wheel set.

The frame of the device <NUM> includes a rear linkage section <NUM> that is interconnected with the front linkage section <NUM>. The front and rear linkage sections <NUM>, <NUM> together form a linkage of the frame. The length of the linkage (and thus the base <NUM>) is adjustable to alter the wheelbase of the device <NUM>. <FIG> shows the device <NUM> with the base <NUM> in a contracted configuration, and <FIG> shows the device <NUM> with the base <NUM> in an extended configuration. As will be appreciated, increasing the length of the wheelbase of the device <NUM> has the effect of increasing the lever arm of the counterbalancing torque that is provided by the weight of the rear drive unit <NUM>, and weights <NUM> that are mounted on the rear drive unit <NUM>. Consequently, with the base <NUM> in the extended configuration, the device <NUM> is able to carry a heavier load with a reduced likelihood of tipping forward over the front wheels 14b (when compared with the base <NUM> in the contracted configuration). However, as will be appreciated, the manoeuvrability of the device <NUM> is reduced with the base <NUM> in the extended configuration at least because the turning circle radius is increased, when compared with the base <NUM> in the contracted configuration.

In this particular embodiments, the front and rear linkage sections <NUM>, <NUM> are hollow square tubes. The rear linkage section <NUM> is received within front linkage section <NUM> so as to be in a telescopic arrangement. Both the front and rear linkage sections <NUM>, <NUM> have transverse holes that align to allow a hitch pin (not shown) to pass through both linkage sections to retain the base <NUM> in a desired configuration.

The rear drive unit <NUM> is connected to the rear linkage section <NUM> by an articulated coupling <NUM>, which is shown in detail in <FIG>. The coupling <NUM> enables the rear drive unit <NUM> to articulate about an articulation axis AX relative to the base <NUM>. In this way, rotation of the rear drive unit <NUM> relative to the base <NUM> and the front wheels 14b enables the device <NUM> to be steered as it traverses a surface. As will be appreciated, a user can rotate the handle <NUM> about the articulation axis AX to rotate the rear drive unit <NUM> about that axis. <FIG> illustrates the device <NUM> with the rear drive unit <NUM> rotated about the articulation axis AX in a direction to cause the device <NUM> to steer to the right with forward movement. Of course, the device <NUM> is also able to steer to the left.

As will be observed from the Figures, in this embodiment the articulation axis AX is transverse to the rotational axis WX of the rear wheels 14a. Further, the articulation axis AX of the articulated coupling <NUM> intersects the rotational axis WX of the rear wheels 14a.

The frame further has a swivel that enables the articulation axis AX to rotate relative to the common axis CX of the front wheels 14b. In this embodiment, the swivel is provided by the interconnection of the articulated coupling <NUM> to the rear linkage section <NUM>, which is inside the hollow tube of the rear linkage section <NUM>. The swivel allows the rear linkage section <NUM> to rotate about its long axis relative to the coupling <NUM>. In this way, the swivel allows the rear drive unit <NUM> to cant relative to the base <NUM> and mast <NUM>. The long axis of the rear linkage section <NUM> defines a swivel axis Sr of the device <NUM>.

<FIG> shows the rear drive unit <NUM> in a neutral position relative to the mast <NUM> and consequently the rotational axes (CX, WX) of the front and rear wheels 14a, 14b are parallel. <FIG> shows the rear drive unit <NUM> in a canted position relative to the mast <NUM> and consequently the rotational axis WX of the rear wheels 14a is inclined relative to the rotational axis CX of the front wheels 14b. Of course, the rear drive unit <NUM> can also cant in the opposite direction. The ability of the rear drive unit <NUM> to cant relative to the base <NUM> and mast <NUM> contributes to the stability of the device <NUM> when traversing uneven ground.

The device <NUM> has swivel limit stops that restrict the rotational range of the swivel. In the illustrated embodiment, the swivel limit stops restrict the rotational range to approximately <NUM>°. As shown most clearly in <FIG>, the coupling <NUM> has a fin <NUM> that projects forwardly into a slot 63a that is formed in the rear end of the rear linkage section <NUM>. The front linkage section <NUM> also has a slot 63b formed in its rear end, so that when the base <NUM> is in its fully contracted configuration, the fin <NUM> projects into both slots 63a, 63b. The side edges of the slots 63a, 63b provide the swivel limit stops, by blocking the fin <NUM> with rotation of the rear drive unit <NUM> about the swivel axis SX, and thus limiting the extent of rotation about the swivel axis SX.

In the embodiment of <FIG>, the supporting head <NUM> has two spaced apart support subassemblies that are interconnected by a cross bar <NUM>. Each support subassembly has a pair of the vacuum grips <NUM>, and a mounting beam <NUM>. Each pair of vacuum grips <NUM> are mounted on opposing ends of the respective mounting beam <NUM>. The ends of the cross bar <NUM> are connected to the middle of each of the mounting beams <NUM>.

The device <NUM> includes a coupling assembly <NUM> that couples the supporting head <NUM> to the carriage <NUM>. As shown most clearly in <FIG>, the coupling assembly <NUM> includes a cross bar mounting portion, which in this embodiment is in the form of a channel <NUM>. The cross bar <NUM> is connected to the channel <NUM> by a first connector <NUM>, such that the supporting head <NUM> is rotatable, relative to the channel <NUM> and about the first connector <NUM>, between a first position (as shown in <FIG> and <FIG>), and second positions. <FIG> and <FIG> show the supporting head <NUM> in a second position.

The device <NUM> has a second connector <NUM> that is configured to releasably connect the cross bar <NUM> to the channel <NUM>. In the example shown in <FIG>, the device <NUM> has two second connectors <NUM>. The second connectors <NUM> are spaced from the first connector <NUM> in the longitudinal direction of the cross bar <NUM>.

<FIG> shows the cross bar <NUM>, and thus also the supporting head <NUM>, in the first position relative to the channel <NUM>. When the cross bar <NUM> is in the first position, the second connectors <NUM> can be arranged to prevent the cross bar <NUM> rotating relative to the channel <NUM> about the first connector <NUM> and out of the first position.

In this embodiment, each second connector <NUM> is in the form of a pin that is attached to the channel <NUM>. Each second connector <NUM> can be moved between an inserted position, in which the shaft of the second connector <NUM> projects inwardly into the channel <NUM>, and a withdrawn position in which the shaft of the second connector <NUM> is outside the channel <NUM>. The cross bar <NUM> has a pin receiving hole <NUM> for each of the second connector <NUM>. When the cross bar <NUM> is in the first position and one or both of the second connectors <NUM> is in the inserted position, the shafts of those second connectors <NUM> locates in a respective one of the pin receiving holes <NUM>.

As will be appreciated, when the second connectors <NUM> are arranged such that the shaft of the pin is in the withdrawn position, which enables the supporting head <NUM> to rotate on the first connector <NUM> and out of the first position (and thus into second positions). <FIG> and <FIG> show the supporting head <NUM> in the first position. <FIG> and <FIG> show the supporting head <NUM> in second positions. As will be appreciated, when the second connectors <NUM> are in the withdrawn positions, the supporting head <NUM> is able to rotate on the first connector <NUM>. This ability to move out of the first position is of great benefit in installing a glass pane G, as the inclination of the glass plane can be manually altered by the installers.

The coupling assembly <NUM> includes a pivot coupling <NUM>, and a rotary coupling <NUM>. The pivot coupling <NUM> enables the cross bar <NUM>, and thus in this embodiment the supporting head <NUM> itself, to be rotated about a first axis X<NUM> between a first position in which sheet material supported by the supporting head <NUM> is in a generally transverse orientation forward direction of the device <NUM>, and a second position in which the sheet material supported by the supporting head <NUM> is in a generally parallel orientation forward direction of the device <NUM>. Further, in this embodiment the pivot coupling <NUM> enables the cross bar <NUM> (and also the supporting head <NUM>) to be rotated from the first position, away from the second position, to a third position. In the third position, sheet material supported by the supporting head <NUM> is oblique to the forward direction of the device <NUM>. In <FIG>, and <FIG>, the device <NUM> is shown with the cross beam <NUM> in the first position. As shown in <FIG>, the first axis X<NUM> is oblique to the longitudinal direction of the mast <NUM>.

<FIG> is a partial view showing the upper mounting beam <NUM> of the supporting head <NUM> in the second position relative to the mast <NUM> and carriage <NUM>. As indicated by angle R<NUM> in <FIG>, the angular displacement between the first and second positions is approximately <NUM>°. <FIG> is a partial view showing the upper mounting beam <NUM> of the supporting head <NUM> in the third position relative to the mast <NUM> and carriage <NUM>. As indicated by angle R<NUM> in <FIG>, the angular displacement between the first and third positions is approximately <NUM>°.

In this particular embodiment, the carriage <NUM> includes an inner pivot coupling portion <NUM>, and the supporting head <NUM> includes an outer pivot coupling portion <NUM>. The inner and outer pivot coupling portions <NUM>, <NUM> are interconnected by a mounting bolt <NUM>. As shown in <FIG>, the carriage <NUM> includes a drop pin <NUM>, and the outer pivot coupling portion includes a plate <NUM>. As particularly shown in <FIG>, the plate <NUM> has a through hole <NUM> that aligns with the drop pin <NUM>, when the supporting head <NUM> is in the first position. When the supporting head <NUM> is in the first position, the drop pin <NUM> can extend through the through hole <NUM> to prevent rotation of the supporting head <NUM> about the first axis X<NUM>. Conversely, the drop pin <NUM> can be lifted to release the supporting head <NUM>, allowing rotation of the supporting head <NUM> first axis X<NUM>.

As shown in <FIG>, the plate <NUM> further includes two limit stops <NUM> that protrude from the plate <NUM>. The limit stops <NUM> abut the inner pivot coupling <NUM>, thereby limiting rotation of the support head <NUM> about the first axis X<NUM>, relative to the carriage <NUM>, as shown in <FIG>.

The rotary coupling <NUM> that enables the cross bar <NUM>, and thus in this embodiment the supporting head <NUM> itself, to be rotated about a second axis X<NUM>, which is generally orthogonal to the first axis X<NUM>. The rotary coupling <NUM> allows sheet material supported by the supporting head <NUM> to be rotated about the second axis X<NUM>.

The coupling assembly <NUM> of this embodiment also includes side shift mechanism <NUM> that, in this embodiment, is arranged to move the rotary coupling <NUM>, and thus also the channel <NUM> and supporting head <NUM>, in a direction that is transverse to the longitudinal direction of the mast <NUM>.

The pivot and rotary couplings <NUM>, <NUM>, and side shift mechanism <NUM> have features similar to those of the devices described and illustrated in International (Patent) Publication No. <CIT> (entitled "A Device For Lifting And Transporting Sheet Material"), filed in the name of Quantum Workhealth Programmes Pty Ltd.

<FIG> show a device <NUM> according to a second embodiment of the present invention. The device <NUM> is intended for use in lifting and transporting sheet material. The device <NUM> is substantially similar to the device <NUM> of <FIG>, and like components of the device <NUM> have the same reference numeral with the prefix "<NUM>".

As will be observed from <FIG>, the device <NUM> has a supporting head <NUM> that has two vacuum grips <NUM> that are attached at opposing ends of a cross bar <NUM>. When compared with the device <NUM> of the first described embodiment, the device <NUM> has a lighter lifting capacity, and does not include drive motors to rotate the wheels 114a, 114b. Accordingly, a user of the device must use manual effort to move the device <NUM>.

The rear linkage section <NUM> of the device <NUM> includes a steerer head <NUM> that is connected to the rear end of the rear linkage section <NUM>. Further, the device <NUM> has a steerer tube <NUM> that extends through the steerer head <NUM>, and is connected at a lower end to an axle housing <NUM>. The upper end of the steerer tube <NUM> projects upwardly of the steerer head <NUM>, and a stem <NUM> is secured to the upper end of the steerer tube <NUM>. The handle <NUM> is connected to the outer end of the stem <NUM>.

A transverse axle passes through the axle housing <NUM>, and a pair of rear wheels 114a are mounted on the transverse axle so as to rotate about a rear wheel axis WX.

In this example, the handle <NUM>, stem <NUM>, steering tube <NUM>, axle housing <NUM>, transverse axle and rear wheels 114a together form a steering assembly of the device.

As shown in <FIG>, the rear linkage section <NUM> of the device <NUM> further includes four weight mounts <NUM>, which in this embodiment extend laterally from the steerer head <NUM>. Weights <NUM> are mountable onto the mounts <NUM> to provide a counterbalance to the weight of sheet material that is supported on the supporting head <NUM>. In this embodiment, the mounts <NUM> are arranged to support the weights <NUM> in two groups. In this way, the weights <NUM> can be evenly dispersed over the two rear wheels 14a.

Each mount <NUM> has a weight retaining member (not shown) that inhibits removal of weights <NUM> from the respective mount <NUM>. In this embodiment, the weight retaining members have a shaft within an external screw thread that is received in internally threaded holes <NUM> on the outer end of each mount <NUM>. Once installed on the mounts <NUM>, the weight retaining members block the weights <NUM> from sliding off the mounts <NUM>. Accordingly, in the event that the device <NUM> moves across a laterally inclined surface, the likelihood of the weights <NUM> unintentionally coming off the mounts <NUM> is reduced.

As shown in <FIG>, each weight <NUM> has a slot that opens to a rear edge of that weight <NUM>. The weights <NUM> are loaded onto the mounts <NUM> with the slots oriented towards the rear of the device <NUM>. As shown in <FIG>, as the steering assembly rotates about the articulation axis AX, the stem <NUM> moves into the aligned slots of those weights <NUM> that are on the corresponding side of the device <NUM>. As will be appreciated, in this particular embodiment it is advantageous for the mass of the weights <NUM> to be fixed relative to the base <NUM>, and rotationally decoupled from the steering assembly.

In this embodiment, the actuator <NUM> is a mechanical actuator, which in this example has a screw shaft <NUM>, a fixed nut <NUM> through which the screw shaft <NUM> extends, and a drive input <NUM> that is rotationally fixed to the screw shaft <NUM>.

The base <NUM> includes a post <NUM> that is attached to the front linkage section <NUM>. The fixed nut <NUM> of the actuator <NUM> connected to the post <NUM>. A user can rotate the drive input <NUM> to cause the screw shaft <NUM> to rotate, and thus extend or contract the actuator <NUM>. In turn, the change of length of the actuator <NUM> causes the pivot section <NUM>, and thus also the mast <NUM>, to rotate about the rotational axis RX.

In this particular embodiment, the drive input <NUM> is a socket to which a tool, such as a cordless drill with a mating socket, is attachable. When desired, the user can attach the mating socket to the drive input <NUM> and operate the drill to rotate the screw shaft <NUM>.

In the embodiment of <FIG>, the device <NUM> has a rear unit that is formed of the front and rear linkage sections <NUM>, <NUM>, and the steering assembly. Advantageously, the device <NUM> can be disassembled, including to disconnect the rear unit from the pivot section <NUM>.

Similarly with the device <NUM> of the first described embodiment, the length of the linkage (and thus the base <NUM>) in this embodiment is also adjustable to alter the wheelbase of the device <NUM>. <FIG> show the device <NUM> with the base <NUM> in a contracted configuration, and <FIG> and <FIG> shows the device <NUM> with the base <NUM> in an extended configuration.

In this particular example, the front end of the rear linkage section <NUM> provides a rear limit stop so as to limit the angular position of the mast <NUM>, and thus also the pivot section <NUM>, relative to the base <NUM> to a first rearmost angular position, when the base <NUM> is in the contracted configuration. In <FIG>, the rearmost angular position is indicated by angle α<NUM>.

With the base <NUM> in the extended configuration, the rear linkage section <NUM> is spaced from the pivot section <NUM>. Accordingly, in this configuration the mast <NUM>, and thus also the pivot section <NUM>, is able to rotate further about the rotational axis RX towards the rear of the device <NUM>, beyond the first rearmost angular position.

The device <NUM> also has a rearward limit stop to limit the angular position of the mast <NUM> relative to the base <NUM> to a second rearmost angular position. In this particular embodiment, the rearward limit stop is provided by a shoulder <NUM> on the outer casing of the actuator <NUM>. As the mast <NUM> is moved to the second rearmost angular position, by the actuator retracting the outer case over the screw shaft <NUM>, the shoulder <NUM> abuts the post <NUM>, which limits the extent to which the pivot section <NUM> and mast <NUM> can rotate in the rearward direction about the rotational axis RX. In <FIG>, the second rearmost angular position is indicated by angle α<NUM>. As will be observed by comparing <FIG> and <FIG>, the angle between the second rear most angular position and a vertical plane is greater than the angle between the first rear most angular position and a vertical plane. In other words, α<NUM> > α<NUM>.

<FIG> show a device <NUM> according to a third embodiment of the present invention. The device <NUM> is intended for use in lifting and transporting sheet material. The device <NUM> is substantially similar to the device <NUM> of <FIG>, and like components of the device <NUM> have the same reference numeral with the prefix "<NUM>" replacing the prefix "<NUM>".

The principle difference is that the device <NUM> includes a propping leg <NUM> that is connected to the frame of the base <NUM> by a bracket <NUM>. The propping leg <NUM> can be pivoted on the bracket <NUM> between a raised position, as shown in <FIG>, <FIG> and <FIG>, and a lowered position, shown in <FIG>. When the propping leg <NUM> is in the lowered position and against a ground surface, the propping leg <NUM> stops the device <NUM> from inadvertently moving across that surface.

Claim 1:
A device (<NUM>, <NUM>, <NUM>) for use in lifting, transporting and installing sheet material (G), the device comprising:
a base (<NUM>, <NUM>, <NUM>) comprising a frame;
wheels on which the base is supported, such that the base is movable across a surface on the wheels, the wheels including:
one or more rear wheels (14a, 114a, 214a) that are connected to the rear of the base in a manner that permits steering of the device during movement across the surface, and
a front wheel set (14b, 114b, 214b) that is connected to the front of the base, the front wheel set including a wheel to each side of the device, the wheels of the front wheel set being rotatable about a common axis (Cx);
a mast (<NUM>, <NUM>,<NUM>) that extends upwardly from the base, and is connected to the base such that the mast is rotatable relative to the base about a rotational axis (RX), the rotational axis being parallel to the common axis;
a front portion that includes the front wheel set and the front of the base, and a rear portion that includes the rear wheels and the rear of the base;
the frame including a linkage (<NUM>, <NUM>; <NUM>, <NUM>; <NUM>, <NUM>) that extends between the front and rear portions of the device, whereby the length of the linkage is adjustable to thereby adjust the wheelbase of the device;
a carriage (<NUM>, <NUM>, <NUM>) that is in engagement with the mast so that carriage is movable along at least a traversable portion of the mast and is guided by the mast;
a supporting head (<NUM>, <NUM>, <NUM>) that is mounted to the carriage, and is configured to support sheet material above the surface;
a lifting mechanism to provide support to the carriage in the longitudinal direction of the mast;
an actuator (<NUM>, <NUM>, <NUM>) that is operable to change the angular position of the mast relative to the base; and
characterized in that it further comprises an articulated coupling (<NUM>, <NUM>, <NUM>) between the front and rear wheels that enables the rotational axis of the rear wheels to rotate within a general horizontal plane and about an articulation axis (AX) relative to the front wheels to thereby steer the device.