Load engagement mechanism for a vehicle transporting elongate loads

Abstract

This invention discloses a tractor unit for transporting long loads (such as wind turbine blades or wind turbine tower sections). The unit includes: a tractor unit body, a wheel assembly, and a load engagement mechanism. The tractor unit body has a longitudinal axis; the wheel assembly includes at least three ground-engaging wheels, one or more of which are driven, and supports, drives, and steers the tractor unit body; the load engagement mechanism, mounted on the tractor unit body, is used to engage and support the long load. The load engagement mechanism is movable along the longitudinal axis from the center of the tractor unit body to its periphery. The load engagement mechanism is configured to be raised and lowered when positioned at the periphery of the tractor unit body.

Description

Technical Field

[0001] The present invention relates to a vehicle for lifting and transporting long loads (e.g., wind turbine blades or wind turbine tower sections). Background Technology

[0002] Long loads, such as wind turbine blades or tower sections, or even other items of similar length, cannot be easily accommodated by conventional vehicles such as articulated trucks. The length of such loads presents significant challenges.

[0003] A preferred mode of transport involves a tractor unit and a trailer unit. The tractor unit is driveable and steerable, and is mounted at one end of the load. The trailer unit supports the span of the load, typically located at the rear half of the load but not at its end. The trailer unit is typically non-driveable, but it can also be driveable and can be steerable or non-steerable. The load itself provides the connection between the tractor unit and the trailer unit. The primary function of the trailer unit is to ensure that the rear end of the load is off the ground and supported so that it can follow the tractor unit.

[0004] While this arrangement is useful, problems remain due to the lack of maneuverability of the tractor unit and / or trailer unit. This is particularly evident when maneuvering loads in confined spaces and when sharp turns are necessary. UK patent application number 1901106.3 aims to address these issues. However, other problems remain regarding the attachment of long loads to the tractor unit. UK patent application number 1901106.3 discloses a load engagement mechanism, and DE202012009041U1 and CN102717745A also disclose similar mechanisms. However, these prior art mechanisms have some shortcomings.

[0005] FR3006958A1 describes a load transport machine comprising: - a motor including a first attachment module for a load; - a separate electric chassis mounted on wheels and including a second attachment module for the load, the load being connected to the first and second attachment modules, each including an attachment device for the load and a swivel support connecting the attachment device to the electric chassis or the motor, the swivel support of at least one of the first and second attachment modules including at least one slide rail perpendicular to the longitudinal axis of the attachment device, on which the attachment device can slide. The attachment device in FR3006958A1 has limitations in movement and direction of movement, which presents drawbacks. This prior art document requires large and heavy counterweights, and the force applied to the lifting mechanism is also significant.

[0006] The teachings of this invention are intended to address at least some of the deficiencies in the prior art. Summary of the Invention

[0007] The present invention provides a tractor unit for transporting long loads (e.g., wind turbine blades or wind turbine tower sections), the tractor unit comprising: a tractor unit body, a wheel set, and a load engagement mechanism, wherein the tractor unit body has a longitudinal axis; the wheel set includes at least three ground-engaging wheels, one or more of which are driven, the wheel set supporting, driving, and steering the tractor unit body; the load engagement mechanism is mounted on the tractor unit body for engaging and supporting the long load, wherein the load engagement mechanism is movable from a central position on the tractor unit body having a longitudinal axis to the periphery of the tractor unit body, and wherein the load engagement mechanism is configured to be raised and lowered when located at the periphery of the tractor unit body.

[0008] By moving the load engagement mechanism from the center of the tractor unit to the periphery, the load can be engaged and lifted, and then moved back to the center for transport. This provides maximum stability and distributes the load evenly across all wheels of the tractor unit. Another advantage of this arrangement is that it eliminates the need for counterweight balancing of the load.

[0009] Furthermore, since the carriage can be positioned around the chassis or tractor unit body for loading, this reduces the thrust and pull forces acting on the lifted load, which is a key design factor for some relatively fragile long loads such as wind turbine blades.

[0010] Preferably, the load engagement mechanism is configured to be raised and lowered only when it is positioned around the periphery of the tractor unit body.

[0011] In addition, the load engagement mechanism can be configured to remain entirely within the footprint of the tractor unit body when in the central position.

[0012] When located around the perimeter of the tractor unit body, the load engagement mechanism can also be configured to be partially located outside the footprint of the tractor unit body.

[0013] Preferably, the load engagement mechanism is mounted on the tractor unit body via a tractor unit carriage configured to move laterally on the tractor unit body. The tractor unit body may include a track, within which the tractor unit carriage is configured to move laterally.

[0014] Preferably, the load engagement mechanism includes a tractor unit carriage cylinder configured to allow the tractor unit carriage to move laterally on the tractor unit body.

[0015] This configuration of the tractor unit carriage, rails, and cylinders enables the load engagement mechanism to move in a controlled manner on the tractor unit.

[0016] Preferably, the hydraulic cylinder of the tractor unit carriage is configured to be floating, allowing it to extend and retract freely along the longitudinal axis, thereby allowing the tractor unit carriage to move in response to external forces acting on it.

[0017] The floating state of the hydraulic cylinder allows it to act as a lateral suspension relative to the load it bears. The tractor unit carriage can move laterally along the longitudinal axis in response to the lateral movement of the load.

[0018] Preferably, the load engagement mechanism further includes a mast attached to the tractor unit carriage. The mast can be attached to the tractor unit carriage via a slewing assembly configured to rotate about a vertical axis relative to the tractor unit carriage and the tractor unit body.

[0019] In addition, the mast can be configured to rotate about a vertical axis relative to the tractor unit carriage and the tractor unit body with the slewing assembly.

[0020] Preferably, the load engagement mechanism further includes a triangular mast bracket attached between the slewing assembly and the mast bracket, the mast bracket being configured to allow the mast to be raised and lowered relative to the mast bracket.

[0021] The mast lifting cylinder is attached to the mast bracket and the mast and is configured to raise and lower the mast.

[0022] The mast bracket and the mast attached thereto are configured to be tilted relative to the tractor unit body.

[0023] The tractor unit may also include a mast bracket tilting cylinder attached between the slewing assembly and the mast bracket, and configured to tilt the mast bracket by extending and retracting.

[0024] Preferably, the mast bracket tilting cylinder is configured to be floating, allowing it to extend and retract freely, thus enabling the mast bracket to tilt in response to external forces acting on it.

[0025] Optionally, the load engagement mechanism further includes a fork-shaped member with a fork-shaped hook configured to engage with a fork groove of the load.

[0026] In addition, a system for transporting long loads (such as wind turbine blades or wind turbine tower sections) is provided, the system comprising two tractor units as described above, such that the two tractor units are connected by the load itself.

[0027] Another independent aspect of the invention provides a mast for lifting long loads (e.g., wind turbine blades or wind turbine tower sections), the mast including a hollow top block at its distal end, the mast being configured to be attached to a tractor unit at its proximal end, wherein the top block is configured to serve as a spacer between the mast and the long load.

[0028] Preferably, the top block is configured to rise and fall along a portion of the mast.

[0029] The top block may include a load interface plate parallel to the mast, which has multiple slots.

[0030] Preferably, the multiple slots are configured to receive bolts protruding from the load. Attached Figure Description

[0031] The embodiments of the present invention are described below by way of example only, with reference to the accompanying drawings, to further illustrate the present invention, wherein:

[0032] Figure 1 This is a side view of the tractor unit, with the load engagement mechanism in the lowered position;

[0033] Figure 2 yes Figure 1 Perspective view of the layout;

[0034] Figure 3 This is a side view of the tractor unit, with the load engagement mechanism in a raised and centered position;

[0035] Figure 4 yes Figure 3 Perspective view of the layout;

[0036] Figure 5 This is a side view of a tractor unit according to the teachings of the present invention, showing the thrust and pull forces when lifting a load;

[0037] Figure 6 This is a simplified side view of the load engagement mechanism in the lowered position;

[0038] Figures 7 to 8 The top block of the load engagement mechanism is shown in different positions;

[0039] Figure 9 It is another view of the top block; and

[0040] Figure 10 This is a top view of two tractor units operating as a system to transport long loads. Detailed Implementation

[0041] exist Figure 1In this designation, 100 generally denotes a tractor unit according to the teachings of the present invention. The tractor unit 100 has a tractor unit body 101 with a longitudinal axis. Six wheel sets and ground-engaging wheels are attached to the tractor unit body 101, three on each side of the tractor unit body 101 or its longitudinal axis. These wheel sets are configured to support, drive, and steer the tractor unit body. A load engagement mechanism 102 for engaging and supporting long loads (not shown) is mounted on the tractor unit body. The load engagement mechanism 102 is movable along the longitudinal axis of the tractor unit body 101 from a central position to a peripheral position. Figure 1 In this configuration, the load engagement mechanism 102 is located at the periphery of the tractor unit body 101. At this periphery, the load engagement mechanism 102 can be raised and lowered. For example... Figure 1 As shown, the load engagement mechanism 102 has been lowered and is ready to engage with the load. It can be seen that when the load engagement mechanism 102 is located around the periphery of the tractor unit body 101, it extends partially beyond the footprint of the tractor unit body. That is, when viewed from above, the tractor unit body 101 defines a rectangular area, and when the load engagement mechanism 102 is located around the periphery of the tractor unit body 101, it extends beyond that rectangular area.

[0042] Figure 2 Shown in perspective view form with Figure 1 The same arrangement is observed. It can be seen that the load engagement mechanism 102 is mounted on top of the tractor unit body 101. Furthermore, the load engagement mechanism 102 includes a tractor carriage 103 configured to move laterally along the longitudinal axis on the tractor unit body 101. The tractor carriage 103 may be equipped with wheels or skids that allow movement of the tractor carriage 103 on the surface of the tractor unit body 101. The load engagement mechanism 102 also includes a mast 104. Figure 1 and Figure 2 In the middle, the mast is in the lowered position, ready to engage with the load.

[0043] Figure 3 The diagram shows a tractor unit 100 with its load engagement mechanism 102 raised and moved along the longitudinal axis to a central position on the tractor unit body 101. It should be understood that at this central position, the load engagement mechanism 102 remains entirely within the footprint of the tractor unit body 101, i.e., within the rectangular area described above in top view. In this central position, the load engagement mechanism remains entirely above the height of the tractor unit body 101. It can only be lowered below the height of the tractor unit body 101 when the load engagement mechanism is located around the periphery of the tractor unit body 101.

[0044] A mast cylinder 105 is provided for raising and lowering the mast 104. Figure 3 In the middle position, the mast cylinder 105 is in the fully extended position, causing the mast to be fully raised. The mast must be fully raised to move to the central position; and it can only be lowered below the height of the tractor unit body 101 (to engage the load) when the mast is located around the periphery of the tractor unit body 101. The load engagement mechanism also includes a slewing assembly 106. This slewing assembly is located between the tractor unit carriage 103 and the mast 104 and is configured to rotate relative to the tractor unit carriage 103 and the tractor unit body 101. That is, the slewing assembly rotates about an axis perpendicular to the top surface of the tractor unit body 101. In this way, the mast 104 (along with the mast cylinder 105 and other components) can rotate with the rotation of the slewing assembly 106. The rotation range is + / - 170° in each direction from the 0° position (e.g., ...). Figure 3 and Figure 4 (As shown). However, during operation, the mast rarely moves more than 90° in either direction.

[0045] The slewing component is designed to enable steering when the tractor unit 100 is traveling with a load. Furthermore, the slewing component facilitates the alignment of the fork 107 of the load engagement mechanism 102 with the fork slots on the load to be lifted. When a load is attached, the slewing assembly can rotate freely within the aforementioned operating range. The slewing assembly 106 allows the engagement mechanism to be pivotally mounted on the tractor unit body about a vertical axis.

[0046] The mast 104 can be pulled back toward the tractor unit body 101, abutting against a buffer 108, which stabilizes the mast and prevents it from swaying. That is, the tractor unit carriage 103 can move laterally, allowing the mast in the lowered position to engage with the buffer 108. This can be useful when the tractor unit 100 is traveling with the mast in the lowered position and no load attached. When engagement with a load is required (e.g., with the fork slots of the aforementioned load), the mast 104 can be moved away from the buffer to allow for rotation. 150mm has been found to be a suitable distance, but any suitable distance can be chosen by those skilled in the art. Return Figure 1 You can see that the mast is in the lowered position and away from the buffer 108, ready to engage with the load.

[0047] A locking pin (not shown) may be provided, which is engaged when the machine is being maintained, i.e., to prevent the mast from rotating / turning when no load is attached and the mast is raised above the tractor unit body 101 for inspection.

[0048] A top block 115 is typically provided at the top or far end of the mast. The main function of the top block 115 is to act as a spacer between the mast and the load, i.e., to keep the top surface of the load away from the mast 104. As will be explained in more detail below, the top block can slide along the mast 104. That is, the top block 115 can be raised and lowered to a suitable height to engage with different load surfaces.

[0049] Figure 4 It shows the relationship with Figure 3 A perspective view of the same arrangement. The load engagement mechanism 102 is in the retracted position, and the mast 104 is raised accordingly. It can be seen that a tractor unit carriage cylinder 109 is provided, one end of which is attached to the tractor unit body 101, and the other end to the tractor unit carriage 103. The extension of the tractor unit carriage cylinder 109 moves the tractor unit carriage 103 (and attached components, such as the mast 104, etc.) towards the periphery of the tractor unit body 101. The retraction of the tractor unit carriage cylinder 109 moves the tractor unit carriage 103 (and attached components, such as the mast 104, etc.) towards the central area on the top of the tractor unit body 101.

[0050] from Figure 4 as well as Figure 2 It can also be seen that the tractor unit 100 includes a track on the tractor unit body 101. The tractor unit carriage 103 is configured to slide or move within the track under the pull or push of the tractor unit carriage cylinder 109. The track is defined by two parallel and opposing rails 110 on the tractor unit body 101.

[0051] The tractor unit also includes a triangular mast bracket 111, which is connected to the slewing assembly 106. The aforementioned mast cylinder 105 is mounted on the mast bracket 111 and the mast 104. As is known in the art, multiple mast cylinders 105 can be used to raise and lower the mast 104.

[0052] The tractor unit carriage 103 can be positioned around the perimeter of the tractor unit body 101 for loading, which reduces the length or size of the triangular mast bracket 111 required for lifting operations. This, in turn, reduces the thrust / pull force acting on the lifted load, a critical factor in blade design for wind turbine blades.

[0053] By enabling the tractor unit carriage 103 to move along the length of the tractor unit body, the load engagement mechanism 102 or the mast 104 can be moved to the periphery of the vehicle, thus requiring only a relatively short triangular mast bracket 111. The movable tractor unit carriage 103 allows the load engagement mechanism 102 to be moved to the rear of the tractor unit body for loading and unloading, and then moved back to the center of the tractor unit body when transporting the load in the longitudinal direction (i.e., along the length of the wind turbine blades) to distribute the load evenly across all wheels. During load transport in this longitudinal direction, the tractor unit carriage 103 is locked in this central position, concentrating the load distribution across all wheels.

[0054] The shorter triangular mast bracket 111 is possible compared to existing technologies because the tractor unit carriage 103 can be moved to the periphery of the tractor unit, thereby reducing the thrust / pull force required to lift the load. Figure 5 This illustrates the importance of the ability to make the tractor unit carriage 103 movable. A long load 500 is attached to the load engagement mechanism. This applies a thrust at the top of the mast, i.e., pushing against the top block; and a pull at the bottom of the mast, i.e., pulling against the fork. The distance between the load 500 and the center of the tractor unit carriage 103 is denoted as X. The shorter this distance X can be maintained, the smaller the thrust / pull force acting on the lifted load. This is a critical design feature when handling relatively fragile loads such as wind turbine blades. If the tractor unit carriage 103 could not move the load engagement mechanism to the periphery of the tractor unit and instead remained in the central position, the distance X would be much longer, and the thrust / pull force would be much greater. A larger triangular mast bracket 111 would be needed, both for reaching the periphery of the tractor unit and for bearing greater forces.

[0055] Back Figure 4 It can be seen that a mast bracket tilting cylinder 112 is also provided, which is connected between the slewing assembly 106 and the mast bracket 111. The function of the mast bracket tilting cylinder 112 is to tilt the mast bracket relative to the slewing assembly 106 (and the tractor unit body 101). Figure 4 as well as Figure 3 As can be seen, the mast bracket is connected to the slewing assembly 106 at two pivot points 113, and is also connected to the slewing assembly 106 via a mast bracket tilting cylinder 112. The extension and retraction of the mast bracket tilting cylinder 112 causes the mast bracket 111 to rotate about the axis defined by the two pivot points 113. That is, the extension and retraction of the mast bracket tilting cylinder 112 causes the mast bracket 111 to tilt relative to the slewing assembly 106 and the tractor unit body 101. The mast bracket tilting cylinder 112 can be located on either side or both sides of the mast bracket 111. The tilting capability of the mast 104 facilitates engagement with a load.

[0056] In the exemplary embodiment shown in the accompanying drawings, the fork-shaped member 107 is provided with fork-shaped hooks 114. These fork-shaped hooks are useful when the load has fork slots. For example, long loads such as wind turbines can be equipped with lifting brackets with fork slots. The engagement of the fork-shaped hooks 114 with the fork slots allows the fork-shaped member to grip the load and ensures that the load does not slip off the fork-shaped member when the tractor unit carriage 103 pulls the mast and load toward the center of the tractor unit body 101. Those skilled in the art will understand that any other type of mechanism can be provided in place of the fork-shaped member 107 and fork-shaped hooks 114, such as using some kind of hook-type hook, so that the load engagement mechanism 102 can grip the load during the pulling phase of the lifting.

[0057] See now Figure 6 The figure shows a simplified view of the load engagement mechanism 102 according to the teachings of the present invention. Reference will now be made to... Figure 6 The operation of the tractor unit will be explained in more detail.

[0058] As can be seen, the tractor unit carriage 103 is located at the periphery of the tractor unit body, i.e., the tractor unit carriage cylinder 109 is in the fully extended state. This allows the mast to extend fully beyond the end of the tractor unit body 101. The mast 104 can be raised and lowered using the hydraulic mast cylinder 105 to obtain the height required for the fork 107 to enter the load fork slot (not shown). The hydraulic mast bracket tilting cylinder 112 can be used to adjust the tilt of the mast bracket 111 and simultaneously adjust the tilt of the mast 104. The slewing assembly 106 allows the mast bracket 111 and the mast 104 to rotate freely about the vertical axis.

[0059] When the fork-shaped member 107 enters the fork slot on the load to be lifted, the mast 104 is raised, causing the fork-shaped hooks 114 on each fork-shaped member 107 to hook onto the rear of the fork slot. After the fork-shaped hooks 114 are engaged, as the mast 104 continues to rise, the top block 115 contacts the top surface of the load being lifted. The top block 115 serves as an interface between the mast 104 and the load. When the load is a wind turbine, the top block 115 is configured to fit downwards onto the blade mounting studs, thereby allowing the mast 104 to press against the blade body structure in the area between the mounting studs to avoid damaging the mounting studs. The following will refer to... Figures 6 to 8This configuration will be described in more detail. As the mast 104 continues to rise, the tractor unit begins to bear the weight of the load, and the pressure in the mast bracket tilting cylinder 112 increases. Once this pressure increase is detected, the tractor unit is configured to drain the fluid in the mast bracket tilting cylinder 112 back to the tank, allowing the cylinder 112 to float or operate in a floating state. As is known in the art, a floating state allows the cylinder to extend or retract freely in response to external forces acting on the hydraulic cylinder. Allowing the mast bracket tilting cylinder 112 to float means that the load engagement mechanism 102 can compensate for any changes in the direction of the long load. Taking a wind turbine blade as an example, the second end, away from the end engaged with the load engagement mechanism 102, may rise or fall in response to ground undulations traversed by the second end. Due to the floating state of the mast bracket tilting cylinder 112, the mast 104 can tilt accordingly to compensate for and reduce any stress that may be applied to the load engagement mechanism 102.

[0060] The load engagement mechanism 102 is also configured to continue raising the mast 104 to a height above the tractor unit body 101. After the mast 104 is raised, i.e., after the fork is raised to a height above the tractor unit body 101, the tractor unit carriage 103 is pulled back to the center position of the tractor unit body 101. The centering of the tractor unit carriage ensures that the weight of the load is evenly distributed on all wheels.

[0061] The load engagement mechanism can also be configured to allow the tractor unit carriage cylinder 109 to float or operate in a floating state. That is, the tractor unit carriage 103 can move freely laterally within a track defined by two parallel opposing rails 110. The degree of lateral movement is limited by the length of the tractor unit carriage cylinder 109. The advantages of this arrangement will be... Figure 10 The explanation is provided below.

[0062] It should be noted that the specific means of making the hydraulic cylinders (e.g., hydraulic cylinders 109 and 112) float are known to those skilled in the art and will not be described in detail here.

[0063] Figures 6 to 8 The top block 115 is shown in more detail. Specifically, Figure 7 The top block 115 is shown in the raised position on the mast, while Figure 8 The top block 115 is shown in the lowered position. A stop 601 is provided on the mast 115 for engaging with the top block 115 in the raised position. The top block can be in the form of a hollow square or rectangular block, or any hollow shape suitable for the load being lifted. However, Figures 6 to 8The top block shown is configured for use with a wind turbine blade 602, which has a plurality of bolts 603 protruding from its surface. To accommodate the bolts 603 of the blade 602, the top block 115 is provided with slots 604 into which the bolts 603 pass when the top block 115 is lowered. That is, the bolts are located within the hollow body of the top block.

[0064] Preferably, the top block 115 can be raised to its original position using a small hydraulic cylinder, a wire rope, and a pulley system, but any suitable lifting device can also be used. Figure 7 As shown, the top block 115 remains in the raised position so that the operator can focus on positioning the fork 107 into the fork slot at the bottom of the load. Once the fork is positioned and hooked into the fork slot, the top block 115 is lowered to a position above the stud 603, as... Figure 8 As shown. During lifting, the top block 115 is pressed against the surface of the blade 602, and no force is applied to the studs. With this configuration, there is no need to remove the studs for transportation, which is a time-consuming task due to the large number of studs on each turbine blade. If the top block 115 with the groove 604 is not used, the force will be applied to the bolts during lifting, causing them to be damaged or bent.

[0065] The initial position of the top block can be manually adjusted in height to accommodate blades of different sizes. Different top block interface pieces can be used for different blade sizes because the blade diameter and stud arrangement are typically different for different blades.

[0066] Figure 9 A view of the top block 115 in its lowered position, as seen from the mast direction, is shown. The mast is not shown for visibility. It can be seen that studs 603 have entered each slot 604 of the top block 115, thus holding them within the hollow top block 115. The load-facing plate of the top block can be considered as a load interface plate 801, which is provided with slots 604 that allow the bolts 603 to enter the hollow top block 115 when the top block is lowered onto it.

[0067] Go to Figure 10 The figure illustrates a tractor unit 100 for transporting long loads according to the teachings of the present invention, the tractor unit 100 being configured to work in conjunction with another tractor unit 100 located at the opposite end of the load. Figure 10The diagram illustrates a system 900 in which two tractor units 100 are connected via a load 901 itself. Although only one tractor unit 100 is shown in steering, it should be understood that the two tractor units can coordinate steering with each other or independently as needed. In this coordinated operation mode, the tractor unit carriage cylinders 109 (on one or both tractor units) are allowed to float to accommodate and compensate for any changes in the distance between the tractor units 100, thereby avoiding damage to the lifted load 901.

[0068] It should also be understood that the tractor unit 100 for transporting long loads according to the teachings of the present invention can work with a wheeled trailer unit, such that the tractor unit and the wheeled trailer unit are connected via the load itself. The trailer unit is typically non-driveable, but can also be driveable, and can be steerable or non-steerable.

[0069] It should be understood that one of the main advantages of the load engagement mechanism according to the present invention is the ability to pick up long, oversized loads outside the footprint of the tractor unit 100 without the need for counterweight balancing. The tractor unit carriage provides the ability to pull the oversized load back to the center of the tractor unit body for maximum stability and to distribute the load evenly to all wheels of the tractor unit.

[0070] Although the above-described embodiment has six wheels, those skilled in the art will understand that this disclosure can be extended to a three-wheeled embodiment, or even to more than four wheels, such as six, eight, or twelve wheels, as needed. The three-wheeled embodiment has been found to have particularly good maneuverability. In this embodiment, the central location for the aforementioned load engagement mechanism is the center of a triangle defined by the three wheels. In this embodiment, when the load engagement mechanism is located around the periphery of the tractor unit body, it also extends partially beyond the vehicle's footprint. That is, when the three-wheeled tractor unit is viewed from above, the tractor unit body defines a triangular area, and when the load engagement mechanism is located around the periphery, it extends beyond that triangular area. Of course, the three-wheeled tractor unit can also have a rectangular shape similar to that shown in the figures.

[0071] It should be understood that although the tractor unit 100 shown in the accompanying drawings includes an operator's cab and a front section adjacent to the cab, the preferred embodiment does not include these components. Instead, the tractor unit 100 is entirely remotely operated by a user standing and walking near the tractor unit. This provides the operator with better visibility during loading and unloading, as well as during the transport of loads.

[0072] In an exemplary embodiment, the tractor unit is configured such that the tractor unit carriage moves longitudinally toward the rear of the tractor unit (the periphery of the tractor unit) to engage a load. However, the teachings of the invention are not limited thereto, and the track on which the tractor unit carriage moves can be positioned in any direction on the top of the tractor unit body. For example, the track can be set at a 90-degree angle to the longitudinal direction shown in the figures, such that the load engagement mechanism engages the load at the side of the tractor unit, rather than at the rear as in the exemplary embodiment. The tractor unit can also be configured such that the load engagement mechanism moves to the front of the tractor unit and lowers at that position to engage the load.

Claims

1. A tractor unit for transporting long loads, comprising: The tractor unit body has a longitudinal axis; A wheelset comprising at least three ground-engaging wheels, wherein one or more ground-engaging wheels are driven, the wheelset supporting, driving and steering the tractor unit body; as well as A load engagement mechanism for engaging and supporting the long load, the load engagement mechanism being mounted on the tractor unit body; The load engagement mechanism is capable of moving along the longitudinal axis from the center of the tractor unit body to the periphery of the tractor unit body. The load engagement mechanism is configured to be raised and lowered when positioned around the periphery of the tractor unit body.

2. The tractor unit according to claim 1, wherein, The load engagement mechanism is configured to be raised and lowered only when it is located around the periphery of the tractor unit body.

3. The tractor unit according to claim 1 or 2, wherein, The load engagement mechanism is configured to remain completely within the footprint of the tractor unit body when in the central position.

4. The tractor unit according to any one of claims 1 to 3, wherein, The load engagement mechanism is configured to remain partially outside the footprint of the tractor unit body when located around the perimeter of the tractor unit body.

5. The tractor unit according to any one of claims 1 to 4, wherein, The load engagement mechanism is mounted on the tractor unit body via a tractor unit slide, which is configured to move laterally along the longitudinal axis on the tractor unit body.

6. The tractor unit according to claim 5, wherein, The tractor unit body includes a track, and the tractor unit carriage is configured to move laterally along the longitudinal axis in the track.

7. The tractor unit according to claim 5 or 6, wherein, The load engagement mechanism includes a tractor unit carriage cylinder, which is configured to allow the tractor unit carriage to move laterally along the longitudinal axis on the tractor unit body.

8. The tractor unit according to claim 7, wherein, The tractor unit carriage cylinder is configured to be floating, thereby allowing it to extend and retract freely, so that the tractor unit carriage can move in response to external forces acting on it.

9. The tractor unit according to any one of claims 4 to 8, wherein, The load engagement mechanism also includes a mast attached to the tractor unit carriage.

10. The tractor unit according to claim 9, wherein, The mast is attached to the tractor unit carriage via a slewing assembly configured to rotate about a vertical axis relative to the tractor unit carriage and the tractor unit body.

11. The tractor unit according to claim 10, wherein, The mast is configured to rotate about the vertical axis relative to the tractor unit carriage and the tractor unit body with the slewing assembly.

12. The tractor unit according to any one of claims 9 to 11, wherein, The load engagement mechanism also includes a triangular mast bracket attached between the slewing assembly and the mast, the mast bracket being configured to allow the mast to be raised and lowered relative to the mast bracket.

13. The tractor unit of claim 12 further includes a mast lifting cylinder attached to the mast bracket and the mast, and configured to raise and lower the mast.

14. The tractor unit according to claim 12 or 13, wherein, The mast bracket with the mast is configured to tilt relative to the tractor unit body.

15. The tractor unit according to claim 14, wherein, The tractor unit also includes a mast bracket tilting cylinder attached between the slewing assembly and the mast bracket, the mast bracket tilting cylinder being configured to tilt the mast bracket by extending and retracting.

16. The tractor unit according to claim 15, wherein, The mast bracket tilting cylinder is configured to be floating, allowing it to extend and retract freely, thus enabling the mast bracket to tilt in response to external forces acting on it.

17. The tractor unit according to any one of claims 9 to 16, further comprising a hollow top block located at the distal end of the mast, the mast being attached to the tractor unit carriage at its proximal end, wherein, The top block is configured to serve as a spacer between the mast and the load.

18. The tractor unit according to claim 17, wherein, The top block is configured to rise and fall along the mast.

19. The tractor unit according to claim 18, wherein, The top block includes a load interface plate parallel to the mast, the load interface plate having multiple slots.

20. The tractor unit of claim 19, wherein the plurality of slots are configured to receive bolts protruding from the load.

21. The tractor unit according to any one of claims 1 to 20, wherein, The load engagement mechanism further includes a fork-shaped member with a fork-shaped hook configured to engage with a fork groove of the load.

22. A system for transporting long loads, comprising two tractor units according to any one of claims 1 to 21, such that the two tractor units are connected via the load itself.

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