WO2025166456A1 - Towing device - Google Patents

Abstract

A towing device is described, for use in lifting rear wheels of a disabled heavy vehicle from a ground or road surface to facilitate towing in the intended direction of travel by a separate towing vehicle without requiring disconnection of the rear-wheel drive mechanism or manipulation of the parking brake system of the heavy vehicle. The towing device includes a cart assembly with a chassis and a lifting assembly with an elevating member and a lifting base connected to the elevating member. The lifting base extends outward from the elevating member and is configured to be oriented at least substantially parallel with an upper or lower surface of a frame of the heavy vehicle. A lifting actuator is connected between the elevating member and the chassis of the cart assembly and configured to raise and lower the elevating member to raise and lower the lifting base.

Description

Towing Device

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority to U.S. Provisional Application No. 63/550,830, filed on February 7, 2024, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

[0002] The present technology is in the field of towing vehicles and is directed to a device for addressing challenges posed by towing heavy vehicles such as tractors and other large vehicles used to transport commercial goods.

BACKGROUND

[0003] Heavy vehicles, which include larger, heavily powered vehicles used for transportation of commercial and/or industrial goods or materials pose several challenges when they become inoperable due to mechanical failure or an accident. Complications associated with the size of heavy vehicles is by far the biggest challenge encountered during towing of a disabled heavy vehicle. The towing industry has developed heavy wreckers and tilt bed trailers to deal with such situations. Tilt bed trailers have limited function due to common height limitations such as overpasses and overhead wires because loading of a heavy vehicle onto a tilt bed trailer could raise it above the height limitations and lead to impact accidents. Therefore, tow vehicles known as “heavy wreckers” provide the preferred means to transport disabled heavy vehicles.

[0004] Since heavy wreckers transport heavy vehicles by lifting only one end of a vehicle, an operator must decide whether to tow a vehicle from the front or from the rear. Principal issues to consider when making this decision are that typical heavy vehicles are rear wheel drive vehicles and have air brake and air spring systems which include fragile components that are not easily adapted to towing conditions.

[0005] The two most common types of brake actuators are “air applied, spring released” and “spring applied, air released”. The former has one chamber for compressed air to be channeled to when the brake pedal is depressed for the brakes to be applied, the spring releases the brakes when the air is evacuated from the chamber. These are conventionally located on the front steer axles of heavy vehicles. The latter has two chambers for compressed air and a strong spring that keeps the brakes applied. When the first chamber is filled with compressed air the spring is overcome, and the brakes are released. The brakes are then applied by channeling compressed air into the second chamber when the brake pedal is depressed, creating a pressure equilibrium between the two chambers allowing the spring tension to then apply the brakes. Evacuating the air from the first chamber applies what is known in the industry as the parking brake. These are commonly found on the drive axles at the rear of the vehicle. If the air tanks are empty, a heavy wrecker operator must supply compressed air from the heavy wrecker to the vehicle being towed to release the parking brake. Releasing of the parking brake can also be carried out manually with the use of a caging bolt. This is a time-consuming endeavor the operators avoid whenever they can. This does not negate the need to supply air to a vehicle equipped with air springs, as in most jurisdictions the air springs must be inflated if wheels of that axle are touching the ground. Conversely, an operator may choose to tow the vehicle from the rear to avoid having to supply air to the vehicle by lifting the wheels equipped with parking brakes off the ground. Front steering axles are not equipped with air suspension with one exception that requires an operator to supply air to the vehicle even while towing it from the rear.

[0006] The conventional automatic transmissions of heavy vehicles are extremely fragile and can be damaged easily when attempting to move a vehicle with the rear wheel turning while the engine is not running, with some manufacturers stating that vehicles with automatic transmissions cannot be moved even a few feet before transmission damage will begin to occur. To mitigate this, operators have two main options. In one option, they can disconnect the driveshaft on the first drive axle, between the drive axle and the transmission. This process that requires the operator to get underneath the vehicle, remove the retaining bolts, and pry the u-joint connecting the driveshaft to the differential out of its mount on the differential. The driveshaft then either needs to be secured so it does not fall out or must be completely removed. This process can be dangerous, time consuming and labor intensive. On some heavy vehicles the bolts are required to be replaced with new ones as these fasteners are torqued to yield, meaning that when installed the bolts are tightened until they stretch slightly. This is done so they do not loosen while driving, but this means they are one time use bolts. Driveshafts must be reinstalled by certified heavy equipment technicians adding to the cost of breakdowns. Alternatively, the operator can choose to remove the axles. This is also a time-consuming option as manufacturers are now requiring that all axles be removed to prevent damage to the differentials and transmission. On a typical heavy vehicle, there are four axles that need to be removed, but there may be up to six, with eight nuts each. This is also a labor-intensive task which is complicated by frequent leakage of oil out of the differentials. The differentials need to be capped, and the oil cleaned up before the operator can safely tow the heavy vehicle. In addition, there is a requirement to manipulate the parking brake system of the heavy vehicle to provide a configuration suitable for towing the heavy vehicle. To avoid such issues, the driver may opt for towing the vehicle from the rear. This will lift the drive wheels off the ground therefore the transmission will not rotate, and no damage will be caused to it.

[0007] With the abovementioned issues, one might conclude that towing a vehicle from the rear seems like it would be the best method, but certain challenges are associated with towing from the rear. When a vehicle breaks down on a roadway, either the truck or the wrecker needs to be turned around so the rear of the vehicle can be lifted by the rear of the wrecker which can be a very risky maneuver when attempting this on a divided highway experiencing even moderate traffic. Care must be taken to not damage lights, air springs, air and electrical lines, and mudflaps. When lifting a vehicle equipped with air springs, the differentials need to be tied up with straps or chains to not overstretch the air springs. Modern heavy vehicles are equipped with plastic and fiberglass aerodynamic devices that are easily damaged if not secured prior to being hauled in a direction other than the intended direction of travel. Securing these devices is not an easy task and can be very time consuming, especially if they have been damaged previously.

[0008] Separate towing dollies have been described in efforts to mitigate some of the issues outlined above. Examples of such towing dollies are described in U.S. Patents 7,017,934 and 8,002,303 each incorporated herein by reference in entirety.

[0009] There continues to be a need for improvements in towing technologies for transporting disabled heavy vehicles. SUMMARY

[0010] The present disclosure describes embodiments of a towing device for use in lifting the rear wheels of a disabled heavy vehicle from a ground or road surface to facilitate towing of the heavy vehicle by a separate towing vehicle. Embodiments of the towing device may include a cart assembly which includes a chassis and at least one axle associated with the chassis, which has at least one pair of wheels connected thereto, and a lifting assembly. The lifting assembly may include an elevating member, and a lifting base connected to a lower end of the elevating member. The lifting base may extend outward from the elevating member and may be configured to be oriented at least substantially parallel with an upper or lower surface of a frame of the heavy vehicle. A lifting actuator may be connected between the elevating member and the chassis of the cart assembly and configured to raise and lower the elevating member thereby raising and lowering the lifting base with respect to the cart assembly such that when the lifting base is connected to the upper or lower surface of the frame of the heavy vehicle, and subsequently raised by action of the lifting actuator, rear wheels of the heavy vehicle will be raised from the ground or road surface.

[0011] The elevating member may be configured to be positioned in a generally perpendicular orientation relative to the ground or road surface.

[0012] The lifting actuator may be provided by one or more lifting hydraulic or pneumatic cylinders configured to raise the elevating member relative to the cart assembly.

[0013] The towing device may further include a casing for the elevating member, wherein the elevating member is configured to slide within the casing and the casing is connected to the chassis.

[0014] The one or more lifting hydraulic or pneumatic cylinders may comprise an assembly of piggyback hydraulic or pneumatic cylinders. The piggyback hydraulic or pneumatic cylinders may be connected between the elevating member and the casing.

[0015] Some embodiments further include a tilt actuator configured to tilt the lifting base in one or both directions away from the generally perpendicular orientation. The tilt actuator may be configured to tilt the elevating member, thereby tilting the lifting base. [0016] Some embodiments further include a pivoting boom extending from the chassis to the elevating member. The boom may include a boom sleeve having a base end pivotally connected to the chassis and a boom extender configured to slide within the boom sleeve by action of a boom extension actuator, wherein an outward facing end of the boom extender is connected to an upper end of the elevating member. The boom extension actuator may be a hydraulic or pneumatic cylinder.

[0017] In some embodiments, wherein a base end of the lifting actuator is pivotally connected to the chassis and an outward facing end of the lifting actuator is pivotally connected adjacent to the outward facing position of the boom.

[0018] The lifting base may be formed of a base sleeve and a base extender, wherein the base extender extends from and retracts into the base sleeve.

[0019] In some embodiments, the tilt actuator is configured to tilt the lifting base relative to the elevating member.

[0020] The lifting base may include one or more crossbars. In some embodiments, at least one of the one or more crossbars comprises a connector configured to connect to a complementary connector on the upper surface of the frame of the heavy vehicle. The complementary connector may be a fifth wheel connector. The one or more crossbars may include one or more additional connection adapters.

[0021] In some embodiments, the towing device further includes one or more stowable casters connected to the chassis.

[0022] In some embodiments, the towing device further includes a power source for providing power to any one of or any combination of: a wheel drive mechanism, a steering mechanism, a braking mechanism, one or more actuators, signal lights, brake lights, hazard lights, message boards and beacons. The power source may be a gasoline or diesel engine, or a battery.

[0023] In some embodiments, the towing device further includes a control module for controlling any one of, or a combination of: the wheel drive mechanism, the steering mechanism, the braking mechanism, the lifting actuator and the tilt actuator.

[0024] In some embodiments, the towing device further includes a wheel drive mechanism coupled to the one or more axles to facilitate driving movement of the towing device when it is not operating in towing of a heavy vehicle by the towing vehicle, the wheel drive mechanism configured to be decoupled from the one or more axles to allow free rotation of the wheels as the heavy vehicle is being towed by the towing vehicle.

In some embodiments, the towing device is configured for connection of an air supply line from the towing vehicle to a decoupling air line on the towing device, the decoupling air line configured to induce decoupling of the drive wheel drive mechanism from the one or more axles, thereby allowing the free rotation of the wheels.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In the Detailed Description section below, embodiments of the present technology are described in relation to the attached figures. These embodiments are provided as examples to provide a better understanding of the invention, how the invention may be put into practice, and to demonstrate some of the advantages of the invention. Wherever possible, similar reference numerals indicate similar components in different embodiments.

Figure 1 is a perspective view of a first embodiment of a towing device 100.

Figure 2A is a side elevation view of the embodiment of Figure 1 showing the towing device 100 with its lifting base 122 in a lowered substantially level position.

Figure 2B is a side elevation view of the embodiment of Figure 1 showing the towing device 100 with its lifting base 122 in an intermediate raised substantially level position.

Figure 2C is a side elevation view of the towing device embodiment 100 with its lifting base 122 in a lowered position tilted upward.

Figure 2D is a side elevation view of the towing device embodiment 100 with its lifting base 122 in a lowered position tilted downward.

Figure 3 is a perspective view showing selected components of the towing device embodiment 100 for the purpose of illustrating how the lifting actuator 132 is connected between the chassis 102 and the elevating member 120 and operates on the elevating member 120 to elevate the lifting base 122 relative to the chassis 102.

Figure 4 is a side elevation view of a towing arrangement showing a heavy wrecker towing a tractor which is elevated by the towing device embodiment 100 via a connection to a fifth wheel on the tractor.

Figure 5 is a side elevation view of another towing arrangement showing a heavy wrecker towing a box truck which is elevated by the towing device embodiment 100 via elevation of the frame or chassis of the box truck.

Figure 6 is a perspective view of another embodiment of a towing device 200.

Figure 7A is a side elevation view of the towing device embodiment 200 with the lifting base 222 in a lowered position, with extension of the base extender 231 and extension of the boom extender 237.

Figure 7B is a side elevation view of the towing device embodiment 200 with the lifting base 222 in a raised position, with extension of the base extender 231 and extension of the boom extender 237.

Figure 7C is a side elevation view of the towing device embodiment 200 with the lifting base 222 in a lowered position, tilted downward, with the base extender 231 retracted inside the base sleeve 229 and the boom extender 237 retracted inside the boom sleeve 239.

Figure 7D is a side elevation view of the towing device embodiment 200 with the lifting base 222 in a lowered position, tilted upward, with the base extender 231 extended and the boom extender 237 retracted inside the boom sleeve 239.

Figure 8 is a side elevation view of the towing device embodiment 200 with the lifting base 222 in a lowered position, tilted completely upward with the base extender 231 retracted inside the base sleeve 229 and the boom extender 237 retracted.

Figure 9 is a rear elevation view of the towing device embodiment 200 with the lifting base 222 in a lowered position, tilted completely upward and the boom extender 237 retracted, as shown in Figure 8. Figure 10 is a cross sectional side elevation view of the towing device embodiment 200 taken along line B — B of Figure 9 with the lifting base 222 in a lowered position, tilted completely upward and the boom extender retracted, as shown in Figure 8, for the purpose of showing detail of the boom extension actuator 242, the tilt actuator 212 and the base extension actuator 244.

Figure 11 is a perspective view showing selected components of the towing device embodiment 200 for the purpose of illustrating how the lifting actuator 232 operates on the elevating member 220 to elevate the lifting base 222 relative to the chassis 202.

Figure 12 is a perspective view showing selected components of another embodiment of the towing device 300 for the purpose of illustrating a lifting actuator embodiment by a set of piggyback hydraulic cylinders 333.

Figure 13 is a schematic diagram indicating functionality of embodiments of the towing device which include a drive mechanism configured to be decoupled when the towing device is operational in a towing operation driven by a towing vehicle.

DETAILED DESCRIPTION

Introduction and Rationale

[0026] As noted briefly in the background section, with some of the problems associated with towing heavy vehicles having been recognized, attempts to provide an auxiliary towing device for use together with a towing vehicle such as a heavy wrecker have been made and are described in US Patents 7,017,934 and 8,002,303.

[0027] US Patent 7,017,934 describes a towing dolly concept which is configured to assist a wrecker with towing a disabled tractor equipped with a fifth wheel connector with towing from the front end and use of the dolly to raise the back end of the tractor such that its back wheels are raised above the road surface. The dolly has a wheeled frame and a lifting portion which is configured to be pivoted and tilted upwards at a forwardfacing end with respect to the wheeled frame to permit it to be connected to the fifth wheel. Following additional connections of the lifting portion to the disabled tractor with chains, an air bag is actuated to force the lifting portion upwards further, which raises the back end of the tractor above the road surface. The lifting portion in this dolly concept is driven upwards at an angle by the action of a lever pushing down against the back end of the lifting frame to cause the forward-facing end of the lifting frame to be lifted upwards, as best seen in Figure 5 of US Patent US Patent 7,017,934. As such, the dolly described in US Patent 7,017,934 is only applicable for towing heavy vehicles equipped with a fifth wheel. It is not useful for towing other heavy vehicles such as box trucks, for example because the lifting frame of this dolly is not arranged to permit lifting from the underside of a frame or chassis of a box truck.

[0028] US Patent 8,002,303 describes another towing device which was developed as an auxiliary towing dolly for towing heavy vehicles. This dolly also has a wheeled frame and a lifting portion. It differs from the dolly described in US Patent 7,017,934 in its lifting arrangement which uses air springs to raise the lifting portion vertically with respect to the wheeled frame. When the lifting portion is raised, it can be moved above the rear frame of the heavy vehicle. If the heavy vehicle is equipped with a fifth wheel connector, the lifting portion remains above the fifth wheel connector and does not connect to the fifth wheel connector. In this arrangement, the forward-facing end of the lifting frame is placed between the fifth wheel connector and the rear of the vehicle’s cab. Then chains are dropped from the lifting portion and wrapped around the axles of the disabled heavy vehicle. Activation of the air springs then raises the lifting portion and causes the rear wheels of the heavy vehicle to be lifted off the road surface to provide the arrangement illustrated in Figure 7 of US Patent 8,002,303. While the operation of the dolly of US Patent 8,002,303 appears to provide a more reliable auxiliary towing arrangement than the dolly of US Patent 7,017,934 by placing the lifting frame generally horizontally as opposed to being tilted, it also has certain disadvantages. For example, since the option for connecting the dolly to a fifth wheel connector of the disabled heavy vehicle is not possible, it is necessary to have a forward-facing end of the lifting portion extending over and above the fifth wheel connector, as shown in the illustration of Figure 8 of US Patent 8,002,303. In actual practice, heavy vehicles equipped with fifth wheel connectors have various vehicle components located between the fifth wheel connector and the rear of the cab, which would tend to interfere with the placement of the forward-facing end of the lifting frame in an arrangement appropriate for connecting chains to the axles of the disabled heavy vehicle. In addition, the same issue exists for the dolly of US Patent 8,002,303 in being applicable only for towing of heavy vehicles by placing the lifting portion above the rear frame of the disabled heavy vehicle. It would not be useful for towing other heavy vehicles such as box trucks, for example.

[0029] The inventor of the present application recognized the shortcomings of the towing dolly devices of US Patents 7,017,934 and 8,002,303 and conceived of an auxiliary towing device for heavy vehicles which is provided with a mechanism to move a lifting base with additional degrees of freedom to permit it to be raised above the rear frame of a disabled heavy vehicle to lift the frame of the heavy vehicle from above, or lowered and placed beneath the rear frame of a disabled heavy vehicle for lifting the rear of the heavy vehicle from below the rear frame of the heavy vehicle. This additional functionality of lifting the rear of the heavy vehicle from below the rear frame of the heavy vehicle provides a useful advantage in permitting a heavy vehicle which does not have an exposed upper rear frame (such as a box truck) to be lifted from the rear to lift its rear wheels above the road surface. Therefore, the towing device described herein has an expanded range of heavy vehicles relative to the dolly devices described in US Patents 7,017,934 and 8,002,303, among other advantages which will be described in detail hereinbelow.

[0030] Various aspects of the present technology will now be described with reference to the figures. Alternative features are introduced in this description. According to the knowledge and judgment of persons skilled in the art, such alternative features may be substituted in various combinations to arrive at different embodiments of the present invention.

First Embodiment

[0031] A first embodiment of a towing device 100 is illustrated in Figures 1-3 and two different arrangements for using this embodiment 100 to tow two different types of heavy vehicles are illustrated in Figures 4 and 5. Towing device 100 includes a cart assembly formed of a chassis 102 with a connected axle and wheels 104. While the present embodiment includes only a single axle with a pair of wheels 104, alternative embodiments may have a larger chassis to accommodate at least one additional axle and wheel set, which may provide enhanced stability and capacity for increased payload if required for certain applications. A control module 108 is fixed to the chassis 102 and includes control elements required to drive operation of various functional components such as the axle to provide driving power to the wheels, power steering functionality to the wheels and various actuators to provide lifting and tilting functionality as described hereinbelow. Other functions that can be controlled by the control module include, but are not limited to electrical, hydraulic and air lines to control a braking mechanism, signal lights, brake lights, hazard lights and beacons such as arrow boards. The control module may include a remote controller to permit the operator to operate the towing device 100 at a distance.

[0032] This particular embodiment 100 includes a set of freely moving casters 110 which are connected to the chassis 102. The casters 110 may be considered optional components provided to keep the main lifting component elevated during the process of coupling the towing device 100 to a disabled heavy vehicle. In some embodiments, the casters 110 are removable, as is desirable when the towing device 110 is engaged with a heavy vehicle for towing and replaceable when it is desirable to move the towing device 100 around an area such as a maintenance facility. In some embodiments, the casters 110 are connected to a conventional jack (not shown) of the type used to raise the front end of conventional trailers. In some embodiments, the towing device 100 includes a stowing arrangement (not shown) for the casters 110 when they are not connected to the towing device 100, or a pivoting arrangement to keep them connected but elevated in a non-operational orientation. In some embodiments, the casters 110 may be provided with a linear actuator to provide steering functionality while retaining a single drive motor. As described in more detail below, having two motors individually coupled to separate back wheels at opposite ends of an axle and at least one selfcentering swivel caster offers improvements in range of motion for operating in restrictive areas such as service yards or indoor service bays. This arrangement also provides for delivery of increased torque to the individual back wheels for steering and for other situations that may require it. In some embodiments, the stowing mechanism for the casters may be a hydraulic or pneumatic stowing mechanism to permit the casters to be raised or stowed while the towing device 100 is coupled to a vehicle.

[0033] The towing device 100 also includes a lifting assembly which includes an elevating member 120 connected to a lifting base 122 via a base connector 130. It is seen in Figures 1 , 2A and 2B that the elevating member 120 is in a substantially vertical orientation, and generally perpendicular to the plane of the ground or road surface. The lifting base 122 in Figures 1, 2A and 2B is shown as oriented generally perpendicular to the elevating member 120 and substantially parallel to the ground surface or road surface. This arrangement provides useful functionality to the towing device 100 because if the elevating member 120 is configured to be oriented generally perpendicular to the ground or road surface in at least one possible configuration, the towing device 100 will be provided in a more compact arrangement than the prior art towing devices which were designed to elevate an elongated lifting portion, such as the dollies described in US Patents 7,017,934 and 8,002,303.

[0034] In the towing device embodiment 100, the elevating base 122 includes a set of three crossbars 125 to facilitate the process of making connections to a disabled heavy vehicle being towed. The crossbar 125 located at the front of the lifting base 122 is shown with a coupler 128 attached thereto which is configured for connection to a fifth wheel connector of a heavy vehicle. In some embodiments, the coupler is of the type conventionally known as a “king pin” for connection to a fifth wheel connector. In other alternative embodiments, a saddle-type connecting mechanism can be provided as a removable adaptor that allows coupling to the top of a flat bed trailer or truck, or any type of vehicle not equipped with a fifth wheel that has adequate clearance on top of the frame members. Means of transporting the towing device behind a wrecker using common adapters may be provided. In some embodiments, the crossbars 125 are removable and replaceable and also movable to different positions of the towing device, if required.

[0035] The elevating member 120 is configured to slide within a casing 124. Another crossbar 126 is connected to the casing 124 in this embodiment. This crossbar 126 is useful for making other connections to higher positions of the heavy vehicle as may be required. Various adapters and connectors may be attached to or incorporated into the crossbars 125 and 126 to facilitate the process of securing the towing device 100 to the heavy vehicle using chains, straps or fabricated brackets. Examples of such alterative connectors may include, but are not limited to, conventional towing connection adapters such as chain hook adapters and frame fork adapters (not shown).

[0036] The lifting assembly is connected to the chassis 102 by a lifting actuator 132. In this particular embodiment 100, the lifting actuator 132 is provided by a pair of hydraulic cylinders, each having a cylinder tube 133 and rod 134, which are shown more clearly in Figure 3. In other embodiments, other mechanical means of effecting linear motion are employed. Examples include pneumatic cylinders, electromechanical actuators, or worm gear actuators, linear actuators, rack and pinion actuators, block and tackle arrangements, or wire, rope or chain hoists with or without pulleys may be configured for lifting operation in an equivalent manner.

[0037] In this embodiment 100, it is seen in Figure 3, which shows selected components of the towing device 100, that the bottom ends of the two cylinder tubes 133 are fixed to a lower plate 136 which is connected via a support bracket 137 to the casing 124 which contains the lifting actuator 132. The rods 133 of the cylinders of the lifting actuator 132 push against an upper plate 135 which is connected to the top end of the elevating member 120. When the rods 133 are completely retracted into the cylinder tubes 133, the elevating member 120 will be at its lowest level, with the lifting base 122 relatively close to the ground.

[0038] When it is required to elevate the lifting base 122 in the process of connecting it to a disabled heavy vehicle and/or raising the back end of the heavy vehicle, the lifting actuator 132 is controlled to extend the rods 134 out of the cylinder tubes 133 thereby pushing the rods upward against the upper plate 135 and raising the elevating member 120 and the connected lifting base 122 relative to the chassis 102. During this process, the elevating member 120 slides upward within the casing 124, which remains stationary because it is attached to the chassis 102. As the elevating member 120 is raised in the direction of the arrow shown in Figure 2B, its upper end emerges from and extends upward from the casing 124, as can be seen in Figure 2B relative to Figure 2A. It is seen in the arrangement shown in Figure 3 and understood from the description above, that the lifting actuator 132 is placed between the elevating member 120 and the chassis 102 of the cart assembly. This arrangement provides a compact and effective lifting configuration for the towing device 100.

[0039] Advantageously, the towing device embodiment 100 also includes a mechanism for controlling the orientation of the lifting base 122 for tilting such that its forward end can be point upward, or downward. These orientations can be seen in Figure 2C (where the lifting base 122 is tilted upward) and Figure 2D, where the lifting base 122 is tilted downward. This functionality is advantageous particularly when the disabled vehicle is located on an uneven road or ground surface. For example, if the wheels of the towing device 100 are located on a relatively level surface but the disabled heavy vehicle is resting on a slightly downward sloping road surface which begins to slope downwards from a location close to the back end of the disabled heavy vehicle, the lifting base can be tilted downward to put it into an orientation which is substantially parallel with the rear frame of the disabled heavy vehicle, such that connection of the lifting base to the rear frame of the heavy vehicle can be controlled by lining up the complementary connectors in an optimal orientation. During a returning to a level surface, the tilt angle of the lifting base 122 may then be adjusted, if deemed necessary. The tilting functionality makes the towing device 100 more versatile by giving operators more flexibility in selecting attachment points and also will aid in providing an arrangement with rear lights and bumper of the chassis being perpendicular to the road surface and at the proper height in case of rear impacts. Once coupled, the tilting mechanism will affect the pitch angle of the towing device 100 but not the disabled heavy vehicle being towed.

[0040] In the present embodiment 100 of the towing device, tilting of the lifting base 122 is generated by a tilt actuator 112 in the form of a pair of cooperating hydraulic cylinders mounted between the chassis an intermediate location on the casing 124. In alternative embodiments, these hydraulic cylinders may be replaced with suitable pneumatic cylinders, electromechanical actuators or worm gear actuators. Figures 2C and 2D demonstrate that retraction of the rod 113 into the cylinder tube 111 pulls the casing 124 backward and this causes an upward tilt of the lifting base 122. Conversely, extension of the rod 113 out of the cylinder tube 111 pushes the casing 124 forward and this causes a downward tilt of the lifting base 122. In this particular embodiment 100, the tilt actuator is configured to provide forward and backward tilting of the elevating member 120 by any angle up to about 15 degrees in each direction with respect to horizontal. In this embodiment 100, the tilting mechanism is separate and independent from the base elevating mechanism described above because the base of the tilt actuator 112 is connected to a longitudinal member 103 of the chassis 102 and the outward extending rod end is connected to the casing 124, which does not move relative to the chassis 102 when the elevating mechanism is operating. The presence of a tilt bracket 138 connected to the support bracket 137 of the casing 124 contributes to smooth operation of this tilting mechanism. [0041] As noted above, this towing device embodiment 100 includes a control module 108. The control module 108 may be configured to control a driving mechanism which may be driven via individual hydraulic or electric motors for each wheel or via a differential power and steering mechanism which is driven by a hydraulic, pneumatic or electric motor. The power source for the motor may be provided by a gasoline or diesel engine or a battery. In some embodiments, the drive mechanism is arranged to be decoupled to permit the wheels to roll freely. The wheels may be equipped with brakes which are controllable from the towing vehicle and the towing device 100 may be driven and steered by driving the hydraulic or electric motors at different speeds, or by applying the brakes at different rates. The driving mechanism is provided with sufficient power to propel the towing device 100 itself, as well as propelling a heavy vehicle connected to the towing device 100. This arrangement is useful in situations where movement of the disabled heavy vehicle across short distances is required, such as moving the towing device 100 within a service yard, into a parking stall or repair bay, or to a more suitable location for coupling to a wrecker. In this case, the drive power of the towing device 100 is used to move the disabled heavy vehicle. In some embodiments, the control module 108 is configured for wireless operation such that an operator can control any of the functionalities described above (driving, steering, braking and operation of lifting and tilt actuators) from a location on the ground near the towing device 100 or from inside the cab of a heavy vehicle connected to the towing device 100. In some embodiments, the steering functionality is generated by moving the wheels at different speeds by either applying brakes to one set of wheels or by having a pair of motors, each connected to opposite sides of the same axle.

[0042] Figure 4 shows how the towing device embodiment 100 is used in conjunction with a heavy wrecker to transport a disabled tractor equipped with a fifth wheel. The wrecker raises the front wheels of the tractor above the road surface and the towing device 100 raises the rear wheels of the tractor above the road surface. This arrangement removes the need to disable the rear wheel drive of the tractor. A connection of the towing device 100 to the fifth wheel connector is made. Other connections are made between the back frame of the tractor and the towing device using chain hooks, frame forks or other conventional connectors prior to elevating the rear wheels of the tractor above the road surface. [0043] Figure 5 shows how the towing device embodiment 100 is used in conjunction with a heavy wrecker to transport a disabled box truck. The wrecker raises the front wheels of the box truck above the road surface and the towing device 100 raises the rear wheels of the box truck above the road surface. This arrangement removes the need to disable the rear wheel drive of the box truck. A connection of the towing device 100 to the underside of the frame of the box truck is made. Other connections are made between the back frame of the tractor and the towing device using chain hooks, frame forks or other conventional connectors prior to elevating the rear wheels of the box truck above the road surface.

[0044] One embodiment of a control system used to control the functionalities of various embodiments of the towing device is illustrated schematically in Figure 13 with a particular emphasis on illustrating control and decoupling of the drive and brake systems of the towing device. At the bottom of Figure 13, there is shown a cross-section of the main components of the towing device which are linked to the drive and brake systems, including motors 662a and 662b, brakes 663a and 663b, decouplers 664a and 664b, input shafts 665a and 665b, half shafts 666a and 666b, brake drums 667a and 667b, wheel hubs 668a and 668b, wheels 669a and 669b and tires 670a and 670b. With reference to the wheel drive portion of the overall system, it can be seen that a power supply 650, which may be provided as either a battery or a generator, is controlled using a controller 654 to operate a hydraulic pump 652 to provide hydraulic fluid to a valve body 656 where it is directed to functionalities including operation of the lift functionality of the towing device (movement of the elevating member) operation of the tilt functionality of the towing device (tilting the lifting base upward or downward), as well as driving of the wheels 669a and 669b of the towing device individually. Hydraulic lines extend from the pump 652 to the valve body 656 and electrical lines extend from the controller 654 to the solenoids 656 which control the four valves within the valve body 654 to operate the lifting, tilting, left drive and right drive functionalities. It is to be understood that provision of separate left and right drive mechanisms permits the towing device to be driven with differential steering in a manner similar to that of a conventional skid-steer machine. This is an advantageous arrangement for maneuvering the towing device around a service bay or service yard either by itself or with a disabled heavy vehicle coupled thereto. [0045] Hydraulic lines extend between the valve body 656 and the motors 662a and 662b. The decouplers 664a and 664b are in communication with the motors 662a and 662b to provide control over the operation of the motors 662a and 662b. The decouplers 664a and 664b are operated by supply air 583 from the tow vehicle 580. Air brake systems used by tow vehicles include two different air sources which are conventionally know as supply air and service air. The main difference between service air and supply air is the purpose of the air they carry and how it's controlled. The service air supply is used to operate the service brakes. The pressure in the service line is controlled by the foot brake or trailer hand brake. The supply air source, also known as the emergency line, supplies air to the trailer's air tanks and controls the emergency brakes. When there's a loss of air pressure in the emergency line, the trailer's emergency brakes will engage. In air brake systems, the supply line usually receives air from the prime mover's park brake air tank. The service line is regulated by the trailer-brake relay valve.

[0046] As noted above, it is a general requirement to have both the left and right drive mechanisms disengaged to allow free rotation of the wheels of the towing device when the towing device is being towed by the tow vehicle 580, either with or without a disabled heavy vehicle also being towed. Therefore, the supply air 583 is connected to an air line leading to the decouplers using a connector 661. When the connection at connector 661 is made and air moves through the air line, air is sent to the decouplers 664a and 664b to initiate decoupling of the motors 662a and 662b, thereby disabling the left and right drive mechanisms. Advantageously, this is done automatically when a driver of the tow vehicle prepares to drive the tow vehicle and conducts the typical supply air engagement operation performed at that time. Conversely, the left and right drive mechanisms are automatically engaged when air is not being sent to the decouplers 664a and 664b and this is advantageous because it is generally useful to have the left and right drive mechanisms operating when the towing device is not being towed by a towing vehicle 580 because the drive mechanisms will assist an operator in maneuvering the towing device by itself, or with a heavy vehicle connected thereto. As outlined above, operation of the towing device at this stage may include moving the towing device to couple it to a disabled heavy vehicle on the side of a roadway or moving the towing device around a service yard or bay. [0047] Figure 13 also illustrates how the brakes 663a and 663b are controlled using service air 581 from the tow vehicle. When the service air line from service air 581 is connected to a corresponding air line on the towing device using connector 660, air is sent to the brakes 663a and 663b to induce brake shoes (not shown) to contact the brake drums 667a and 667b which contact the wheels 669a and 669b. In the absence of service air 581 from the tow vehicle, the brakes will not operate. Provision of braking functionality is more important while the towing device is being towed by a tow vehicle 580 (for safety reasons involved in slowing the entire towing assembly while driving) than in situations where the towing device is being driven by an operator on the ground using the drive mechanisms of the towing device because the latter operation will tend to be conducted at much slower speeds. Furthermore, the holding capabilities of hydraulic motors provide sufficient braking force at low speeds so that brakes are not required when the hydraulic motors are coupled to the wheels.

Second Embodiment

[0048] A second embodiment 200 of a towing device will now be described with reference to Figures 6 to 11. This second embodiment 200 also includes a cart assembly which includes a chassis 202 and an axle connected to a set of wheels 204 and casters 210 arranged in a similar manner as described for embodiment 100, which also may be removeable and/or mounted on jacks in alternative embodiments. The towing device embodiment 200 also includes a control module 208 for controlling any or all of the functionality to embodiment 200 which was described above for embodiment 100, including but not limited to drive power, steering power, brakes, control of actuators, lights, beacons and other optional elements as may be required.

[0049] This second towing device embodiment 200 includes a lifting assembly formed of components which are separate from the cart assembly. The lifting assembly includes elevating member 220 which is configured to adopt a number of different orientations including an orientation which is generally perpendicular to the ground or road surface as best seen in Figures 6, 7A, 7C, 7D, 8 and 10. The elevating member 220 is mounted at a forward facing end of a boom 245, which in this particular embodiment, is formed of a boom sleeve 239 and a boom extender 237 which is configured to extend from and retract into the boom sleeve 239. The boom extender 237 is in the extended position in Figures 7A and 7B and in the retracted position (within the boom sleeve 239) in Figures 6, 7C, 7D, 8, 10 and 11. It is to be understood that the telescoping function of the boom 245 is optional and an alternative, more compact embodiment of the towing embodiment 200 has a single boom member equivalent to the boom sleeve 239 which connects directly at its outward facing end to the upper end of the elevating member 220.

[0050] In embodiment 200 of the towing device, the boom extender 237 is connected to an upper end of the elevating member 220 at fixed angle of about 90 degrees. This angle does not change during the process of raising and lowering the elevating member 220. However, as described in more detail below, when the boom 245 is raised from its position in Figure 7A to its position in 7B the angle of the boom 245 changes relative to a main plane of the chassis 102 and this change in angle, causes the elevating member 220 to depart from its substantially perpendicular orientation relative to the ground or road surface as seen in Figure 7B. In an alternative embodiment, a cylinder could be mounted between the boom 245 and the elevating member 220, to provide a means for changing the angle noted above.

[0051] As noted above, the boom 245 is raised relative to the chassis 102. This movement of the boom 245 is driven by a lifting actuator 232 which in this particular embodiment takes the form of two hydraulic cylinders, each mounted between the chassis 102 and a forward end of the boom sleeve 239. As the rod 234 of the lifting actuator 232 is extended, the entire boom 245 is moved upwards at an angle, relative to the chassis 102 with pivoting of the boom 245 on a hinge 241 connecting the boom 245 to the chassis 102.

[0052] The illustrated embodiment 200 with boom sleeve 239 and boom extender 237 provides for extension of the boom 245 with control by a boom extension actuator 242 illustrated in the cross-sectional view of embodiment 200 shown in Figure 10. The boom extender 237 provides the capability to extend the lifting base 222 outward from the chassis to provide finer control over positioning of the lifting base 222 in an optimal position to make connections between the lifting base 222 and the rear frame of the disabled heavy vehicle.

[0053] In this embodiment 200 of the towing device, the elevating member 220 is hollow and a tilt actuator 212 which may be a hydraulic or pneumatic cylinder (or another type of actuator such as an electromechanical actuator or worm gear actuator), is located inside the elevating member 220 as shown in the cross-sectional view of Figure 10, where it is seen that elevating member 220 is pivotally connected to the lifting base 222 and complete extension of the tilt actuator 212 pushes causes the outer end of lifting base 222 to pivot upwards because the pivoting connection is made using a hinge 243. Conversely, when the tilt actuator 212 is retracted, the connected end of lifting base 222 is pulled upward to the right side in the orientation shown in Figure 10 and this causes the outward end of the lifting base 222 to move downward. The lowermost down-tilted orientation of the lifting base 222 is shown in Figure 7C, where the tilt actuator 212 is completely retracted. It is to be understood that the orientation of the lifting base 222 shown in Figures 8, 10 and 11 is generally intended to provide a non-functional spacesaving orientation which would be useful when the device is being towed behind another vehicle to a location of a disabled heavy vehicle, when it is being stored, or when it is being moved around a service facility under rear wheel power control. However, there may be situations where the vertical orientation could be useful in coupling to certain types of vehicles.

[0054] Functional orientations of the lifting base 222 are shown in Figures 7A, 7B, 7C and 7D. These orientations may be useful during the process of making connections between the towing device 200 and the rear frame of a disabled heavy vehicle.

[0055] In a comparison of Figures 7A to 7D with Figures 8, 10 and 11 , it can be seen that embodiment 200 of the towing device has a lifting base 222 which is formed of a base sleeve 229 and a base extender 231. The base extender 231 can extend from, and retract into, the base sleeve 229 in order to change the length of the lifting base 222. This is an optional arrangement. This functionality is driven by a base extension actuator 244 which is seen in the cross-sectional view of Figure 10. The base extension actuator 244 is located inside hollow base sleeve 229 and connected between the base sleeve 229 and the base extender. In general terms, if an embodiment of the lifting base includes a base sleeve and a base extender 231. The base extender 231 may include a forward-facing crossbar such as crossbar 225 but the base extender 231 may not include intermediate and rearward crossbars because the presence of such intermediate and rearward crossbars is incompatible with the telescoping motion. However, the base sleeve 229 may include crossbars. In an alternative embodiment which does not have a telescoping lifting base, the lifting base 122 of embodiment 100 could be used instead of lifting base 222 in embodiment 200 and include all three crossbars 125.

Third Embodiment

[0056] A third embodiment of the inventive towing device 300 is shown in Figure 12 in a back perspective view. This embodiment uses as the lifting actuator, a hydraulic lifting cylinder arrangement which incorporates a pair of hydraulic cylinders, each in an arrangement known conventionally as a “piggyback hydraulic cylinder”. A piggyback cylinder has two similar cylinders linked together in opposing orientation such that the rod of one cylinder extends in a first direction and the rod of the other cylinder extends in the opposite direction. This arrangement is useful because it provides a longer total rod stroke (the sum of the distance covered by each of the two rods) within the limited space available on the towing device 300. In the towing device embodiment 300, there are two piggyback cylinder sets spaced apart from each other, with each set being of similar construction and formed of a pair of connected cylinder tubes 333. In each set, the outer cylinder tubes 333 (in the orientation shown in Figure 12) have similar lower rods 334b extending downward therefrom and the inner cylinder tubes 333 have similar upper rods 334a extending upward therefrom. This hydraulic lifting arrangement is configured to provide extension of all four rods, 334a and 334b at the same rate, to raise or lower the elevating member 320 of the towing device 300. As in other embodiments, this lifting actuator is connected between the elevating member 320 and the casing 324, such that extension or retraction of the rods 334a and 334b causes sliding movement of the elevating member 320 within the casing 324. More specifically, the ends of the upper rods 334a are connected to the elevating member 320 and the ends of the lower rods 334b are connected to the casing 324 which itself is connected to the chassis 302. The advantage provided by this hydraulic lifting arrangement is that the lifting base 322 is provided with a greater vertical lifting range with a smaller cylinder length. It is to be recognized that alternative embodiments may include an arrangement of one or more telescoping hydraulic cylinders, where a smaller diameter rod resides within the diameter of another rod, which would provide a similar advantage of providing a longer rod stroke within a smaller cylinder. However, such telescoping cylinders tend to be more expensive to manufacture and maintain and thus such alternative embodiments will tend to be less preferred. In some embodiments, the piggyback cylinders are pneumatic piggyback cylinders instead of hydraulic piggyback cylinders.

Additional Alternative Embodiments and Advantages

[0057] In an alternative embodiment, a simplified version of the towing device that does not have a mechanism to disconnect the drive motor, actuators, lights and beacons, and other functions could be manufactured as a shop tool for repair facilities. Some embodiments of such a simplified version exclude the functionality provided by the tilt actuator. Using conventional equipment, the process of moving a disabled heavy vehicle into a repair bay requires two people, one to run a piece of machinery and another to steer the heavy vehicle. The disabled heavy vehicle either needs to be supplied with air to release the brakes so the wheels will roll, and the vehicle can be pulled or pushed around the yard, or the rear of the vehicle needs to be lifted and pushed around the yard while someone steers the vehicle. This conventional process requires some skill and diligence to avoid damage to the heavy vehicle. In contrast, embodiments of the towing device described herein are easier to maneuver in restrictive spaces and would only require one operator to move the vehicle into a repair bay, and cost substantially less than the loaders and skid steers currently used for this process. The other option available to heavy equipment technicians is to work on the vehicle outside, which is not preferable during inclement weather.

Example of Operation of the Towing Device

[0058] The following is a brief description of how the towing device would be used in a service call for towing a disabled heavy vehicle which is located on the shoulder of a highway as well as providing a replacement heavy vehicle in a process which is known in the art as a “tractor swap.”

[0059] The service operator receives a call for a tractor swap, where the operator must pick up a replacement heavy vehicle from one location, tow it to the location of the disabled heavy vehicle, where the original driver may then connect it to the transport trailer and continue with delivering the transport trailer to its destination while the service operator tows the disabled heavy vehicle to a repair facility. To initiate this process, the operator connects an embodiment of the towing device to a wrecker (tow vehicle) using any conventional trailer type connection on a forward-facing crossbar of the towing device, or on another component of the towing device. This operation may include connection of supply air and service air lines from the wrecker to the towing device generally as described in the description above in connection with the system embodiment of Figure 13, for example. Performing this operation enables the wheels of the towing device to rotate freely, in embodiments of the towing device which include a drive mechanism for the wheels. At this point, the towing device essentially becomes a non-powered trailer and would not normally be used for pushing or driving the entire combination for any extended period. However, if a wrecker were to become immobilized due to snow or ice, or become mired, the air could be disconnected from the towing device to re-engage the wheel drive mechanism of the towing device, thereby permitting the towing device to be used to move the combination for a short distance.

[0060] The process of engaging the towing device to the wrecker should take less than 5 minutes. The operator then drives the wrecker with the connected towing device to the location of the replacement heavy vehicle and unhooks the towing device without moving the wrecker. This process re-engages the drive mechanism for the wheels, thereby facilitating movement of the towing device over to the replacement heavy vehicle using the power drive. The lifting base of the towing device is then connected to the frame of the replacement heavy vehicle either from the top surface of the exposed rear frame or mounted cargo deck of the heavy vehicle or to the fifth wheel and rear frame of the heavy vehicle frame (for example in the case of a conventional tractor) or to the underside of the rear of the heavy vehicle frame (for example in the case of a box truck which does not have ana upper exposed rear frame). Once the connection is made (using chain hooks, frame forks and/or other conventional connectors such as a fifth wheel connector for example), and the rear wheels of the replacement heavy vehicle are raised using the elevating member and lifting base of the towing device while the front wheels of the replacement heavy vehicle remain on the ground or road surface, the operator then uses the power drive of the towing device to drive the connected combination over to the wrecker. The operator then hooks the wrecker to the front of the replacement heavy vehicle using conventional methods, uses the wrecker to raise the front wheels of the replacement heavy vehicle and connects the air and electric lines to the towing device to provide electrical power and air supply for brakes and/or other functions. This process also disengages the drive mechanism of the towing device as described above. The operator then drives the wrecker, towing the connected replacement heavy vehicle with the connected towing device to the location of the disabled heavy vehicle while all wheels of the replacement heavy vehicle are raised above the road surface.

[0061] Arriving at the location of the disabled heavy vehicle on the shoulder of a highway, the operator stops the wrecker behind the disabled heavy vehicle and disconnects the towing device and the wrecker from the replacement heavy vehicle. The wrecker is then disengaged from the replacement heavy vehicle and moved to the front of the disabled heavy vehicle, where it is connected to the front end of the disabled heavy vehicle to permit it to be pulled forward away from the trailer using conventional sliding elements known as “skates” beneath the rear wheels of the disabled heavy vehicle, a process which is acceptable for moving a disabled heavy vehicle for a distance of a few feet without causing the rear wheels to turn and cause damage to the rear wheel drive mechanism. The disabled heavy vehicle is then towed away from its transport trailer with the skates to a distance sufficient to permit the replacement heavy vehicle to line up in front of the trailer and connect to the trailer. Following connection of the replacement heavy vehicle to the trailer, the driver can continue with the trailer delivery using the replacement heavy vehicle.

[0062] At this point, the towing device is driven to the rear of the disabled heavy vehicle and connected to the rear frame of the disabled heavy vehicle using the power drive and the lifting base of the towing device is connected to the frame of the replacement heavy vehicle either from the top surface of the exposed rear frame or mounted cargo deck of the heavy vehicle, or to the fifth wheel and rear frame of the heavy vehicle (for example, in the case of a conventional tractor) or to the underside of the rear of the heavy vehicle frame (for example in the case of a box truck, which does not have an upper exposed rear frame). Once the connection is made (using chain hooks, frame forks and/or other conventional connectors such as a fifth wheel connector for example), and the rear wheels of the replacement heavy vehicle are raised, the pneumatic and electrical connections are made, the drive mechanism of the towing device is disengaged as described above, and the wrecker can safely tow the combination to a repair facility.

[0063] At the repair facility, the wrecker is disconnected from the disabled heavy vehicle. If the front wheels of the disabled heavy vehicle are functional, the towing device (which remains connected to the rear frame of the heavy vehicle) can be used to drive the disabled heavy vehicle into a repair bay where it is facing the proper direction to perform service operation. At this stage, the towing device may be disconnected and either stored or picked up by its owner and transported by towing it to another location.

[0064] There are several advantages provided by various stages of this process. The operator is not required to work beneath the disabled heavy vehicle in a dangerous environment on a highway shoulder to disconnect a driveshaft in a process that could damage it. In addition, there is no need to tow the disabled heavy vehicle from the rear and strap down aerodynamic devices of the disabled heavy vehicle, there is no need to turn the wrecker around on the road and there is no need to turn the replacement heavy vehicle around. Furthermore, there is no need to supply air to the disabled heavy vehicle, and placement of the disabled heavy vehicle into a repair bay is facilitated using the drive mechanism, which can be controlled remotely in some embodiments. In most situations where the towing device is used, the height, length, width, and weight of the combination of the towing vehicle, the disabled vehicle and the towing device remain within the current legal limits without the need of oversize permits.

[0065] If a fixed or variable message board and beacon lights are included and powered by the towing device, all individuals involved in this operation are kept safer by warning motorists to reduce speed and drive carefully. The towing device may be towed to breakdown locations and from repair facilities with a smaller truck leaving the bigger wrecker units available for other more serious breakdown situations.

Definitions

[0066] As used herein, the term “generally perpendicular” means to within about 5 degrees of being perpendicular. Stated differently, generally perpendicular means having an angle from about 85 degrees to about 95 degrees with respect to a reference plane.

[0067] As used herein, the term “substantially parallel” means to within about 2 degrees of being parallel to a reference plane.

[0068] As used herein, the term “heavy vehicle” refers to any vehicle configured for transporting commercial or industrial goods or materials which weighs more than about 2.5 tons when a container integrally associated with the vehicle is empty or when the vehicle is not connected to a separate trailer.

[0069] As used herein, the term “actuator” refers to a device that causes a device to operate. As such, the term “lifting actuator” refers to any device capable of lifting a given component, the term “tilt actuator” refers to any device capable of tilting a given component, and the term “extending actuator” refers to any device capable of extending a given component.

Equivalents and Scope

[0070] Other than described herein, or unless otherwise expressly specified, all of the numerical ranges, amounts, values and percentages, such as those for amounts of materials, elemental contents, times and temperatures, ratios of amounts, and others, in the following portion of the specification and attached claims may be read as if prefaced by the word "about" even though the term "about" may not expressly appear with the value, amount, or range. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

[0071] Any patent, publication, internet site, or other disclosure material, in whole or in part that is said to be incorporated by reference herein is incorporated herein only to the extent that the incorporated material does not conflict with existing definitions, statements, or other disclosure material set forth in this disclosure. As such, and to the extent necessary, the disclosure as explicitly set forth herein supersedes any conflicting material incorporated herein by reference. Any material, or portion thereof, that is said to be incorporated by reference herein, but which conflicts with existing definitions, statements, or other disclosure material set forth herein will only be incorporated to the extent that no conflict arises between that incorporated material and the existing disclosure material. [0072] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0073] While this invention has been particularly shown and described with references to embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.

Claims

1. A towing device for use in lifting rear wheels of a disabled heavy vehicle from a ground or road surface to facilitate towing of the heavy vehicle by a separate towing vehicle, the towing device comprising: a cart assembly comprising: a chassis; and one or more axles associated with the chassis, the axle having at least one pair of wheels connected thereto; and a lifting assembly comprising: an elevating member; a lifting base connected to a lower end of the elevating member, the lifting base extending outward from the elevating member and configured to be oriented at least substantially parallel with an upper or lower surface of a frame of the heavy vehicle to facilitate a connection thereto; and a lifting actuator connected between the elevating member and the chassis of the cart assembly, the lifting actuator configured to raise and lower the elevating member thereby raising and lowering the lifting base with respect to the cart assembly such that when the lifting base is connected to the upper or lower surface of the frame of the heavy vehicle, and subsequently raised by action of the lifting actuator, rear wheels of the heavy vehicle will be raised from the ground or road surface.

2. The towing device of claim 1, wherein the elevating member is configured to be positioned in a generally perpendicular orientation relative to the ground or road surface.

3. The towing device of claim 1 or 2, wherein the lifting actuator is provided by one or more lifting hydraulic or pneumatic cylinders configured to raise the elevating member relative to the cart assembly.

4. The towing device of any one of claims 1 to 3, further comprising a casing for the elevating member, wherein the elevating member is configured to slide within the casing and the casing is connected to the chassis.

5. The towing device of claim 3 or 4, wherein the one or more lifting hydraulic or pneumatic cylinders comprise an assembly of piggyback hydraulic or pneumatic cylinders.

6. The towing device of claim 5, wherein the piggyback hydraulic or pneumatic cylinders are connected between the elevating member and the casing.

7. The towing device of any one of claims 2 to 6, further comprising a tilt actuator configured to tilt the lifting base in one or both directions away from the generally perpendicular orientation.

8. The towing device of any one of claim 7, wherein the tilt actuator is configured to tilt the elevating member, thereby tilting the lifting base.

9. The towing device of any one of claims 1 to 8, further comprising a pivoting boom extending from the chassis to the elevating member.

10. The towing device of claim 9, wherein the boom comprises a boom sleeve having a base end pivotally connected to the chassis and a boom extender configured to slide within the boom sleeve by action of a boom extension actuator, wherein an outward facing end of the boom extender is connected to an upper end of the elevating member.

11. The towing device of claim 10, wherein the boom extension actuator is a hydraulic or pneumatic cylinder.

12. The towing device of any one of claims 9 to 11 , wherein a base end of the lifting actuator is pivotally connected to the chassis and an outward facing end of the lifting actuator is pivotally connected adjacent to the outward facing position of the boom.

13. The towing device of any one of claims 9 to 12, wherein the lifting base is formed of a base sleeve and a base extender, wherein the base extender extends from and retracts into the base sleeve.

14. The towing device of any one of claims 7 to 13, wherein the tilt actuator is configured to tilt the lifting base relative to the elevating member.

15. The towing device of any one of claims 1 to 14, wherein the lifting base comprises one or more crossbars.

16. The towing device of claim 15, wherein at least one of the one or more crossbars comprises a connector configured to connect to a complementary connector on the upper surface of the frame of the heavy vehicle.

17. The towing device of claim 16, wherein the complementary connector is a fifth wheel connector.

18. The towing device of any one of claims 15 to 17, wherein the one or more crossbars include one or more additional connection adapters.

19. The towing device of any one of claims 1 to 18, further comprising one or more stowable casters connected to the chassis.

20. The towing device of any one of claims 1 to 19, further comprising a power source for providing power to any one of or any combination of: a wheel drive mechanism, a steering mechanism, a braking mechanism, one or more actuators, signal lights, brake lights, hazard lights, message boards and beacons.

21. The towing device of claim 20, wherein the power source is a gasoline or diesel engine, or a battery.

22. The towing device of claim 20 or 21 , further comprising a control module for controlling any one of or any combination of: the wheel drive mechanism, the steering mechanism, the braking mechanism, the lifting actuator and the tilt actuator.

23. The towing device of any one of claims 1 to 19, further comprising a wheel drive mechanism coupled to the one or more axles to facilitate driving movement of the towing device when it is not operating in towing of a heavy vehicle by the towing vehicle, the wheel drive mechanism configured to be decoupled from the one or more axles to allow free rotation of the wheels as the heavy vehicle is being towed by the towing vehicle.

24. The towing device of claim 23, which is configured for connection of an air supply line from the towing vehicle to a decoupling air line on the towing device, the decoupling air line configured to induce decoupling of the drive wheel drive mechanism from the one or more axles, thereby allowing the free rotation of the wheels.

25. The towing device of claim 23 or 24, which is configured for connection of an air service brake line from the towing vehicle to an air brake line on the towing device to provide control of brakes of the towing device by an operator of the towing vehicle.