Patent Application
20090008175
The following disclosure relates generally to reach-type vehicles having a stabilizing system to resist tipping forces.
Adjustable support systems for vehicles have been developed to increase the stability of the vehicle during various types of operations. As an example, adjustable support systems have been used to add stability while operating a lift with a basket or while operating other tools (e.g., tools found on excavators). Increased stability is often provided by laterally extending vehicle support systems having wheels on telescoping axles that can be extended to increase the width of the vehicle's wheel track. Other support systems include laterally deployable stabilizer arms, independent from the wheels, that can be lowered in a vertical plane to effectively increase the width of the vehicle's track.
A vehicle support system is shown in published U.S. Patent Application Publication No. 2005/0212253, entitled “Vehicle Support System,” and published Sep. 29, 2005. The system includes two support assemblies pivotally coupled to a base. A control mechanism couples the two support assemblies together and controls the pivotal movement of the support assemblies relative to the vehicle's base between spread and stowed positions. While the disclosed vehicle support system provides a significant improvement over the prior art, there is a need for a vehicle with a variable wheelbase to provide improved performance in certain areas.
The present invention is generally directed toward a vehicle having a variable length wheelbase. In one embodiment, the vehicle has a base having a longitudinal axis and first and second body portions. The first body portion is coupled to a first set of wheels, and the second body portion is coupled to a second set of wheels longitudinally spaced apart from the first wheels to define a vehicle wheelbase. The first and second body portions are moveable relative to each other in a direction substantially parallel to the longitudinal axis so as to move the base between extended and retracted positions. When the base is in the retracted position the vehicle's wheelbase has a first length, and when the base is in the extended position the wheelbase has a second length greater than the first length. A boom is pivotally coupled to the base. The boom is moveable relative to the body portion in response to movement of the base between the extended and retracted positions. The boom moves toward a lowered position when the base is moved toward the extended position, and the boom moves toward a raised position when the base is moved toward the retracted position.
Another aspect of the invention is directed toward an extendible vehicle assembly having a body with a longitudinal axis and first and second body portions coupled to first and second ground-engaging members, respectively. The first and second ground-engaging members are longitudinally spaced apart from each other to define a variable support base. The first and second body portions are moveable longitudinally between extended and retracted positions. When the body is in the retracted position the support base has a first length, and the when the body is in the extended position the support base has a second length greater than the first length. An extendible boom is pivotally coupled to the base and is moveable between raised and lowered positions in a vertical plane relative to the body. The boom assembly simultaneously moves toward the lowered position when the body is moved toward the extended position, and the boom assembly simultaneously moves toward the raised position when the body is moved toward the retracted position.
The present disclosure describes vehicle support systems. Several specific embodiments are set forth in the following description and in
The body 14 of the vehicle 10 has a front portion 18 coupled to a front axle 20 and steerable front wheels 22. The body 14 also has a rear portion 24 coupled to a rear axle 26 and rear wheels 28, which are spaced longitudinally apart from the front axle 20 and front wheels 22. The distance between the front and rear wheels 22 and 28 defines a wheelbase 30 of the vehicle. As discussed in greater detail below, the front and rear portions 18 and 24 of the body 14 are longitudinally moveable in a direction substantially parallel with the vehicle's longitudinal axis 32 between an extended position (
In the illustrated embodiment, the body 14 includes a drive system 34 operatively coupled to the rear wheels 28 and configured to propel the vehicle 10 forwardly or rearwardly. The drive system 34 in the illustrated embodiment includes the power plant 35 that has an electric motor to drive the rear wheels 28. In other embodiments, power plant 35 can include an internal combustion engine, a hybrid system with an electric motor and an combustion engine, or one or more other motors. In another embodiment, the vehicle 10 can have a front wheel drive configuration, wherein power from the power plant 35 is provided to the front wheels 22. In yet another embodiment, the vehicle 10 can have an all-wheel drive configuration wherein power from the power plant 35 is simultaneously provided to the front and rear wheels 22 and 28 to propel the vehicle. In yet another embodiment, the drive system can be shifted between rear wheel drive, front wheel drive, and all-wheel drive configurations.
The vehicle 10 also has a control system 36 that allows a user to operate the various aspects of the vehicle. The control system 36 is also configured to automatically control or limit other aspects of the vehicle's operation. In the illustrated embodiment, the control system 36 is coupled to the drive system 34 so as to allow an operator to control the speed and direction of the vehicle's movement. The control system 36 is also coupled to a steering system 38 that is used to control the angular orientation of the front wheels 22 (or other steerable wheels). The control system 36 also regulates the speed at which the vehicle 10 can be driven as a function of the boom's angular orientation of the base's position between the extended and retracted positions.
In the illustrated embodiment, a control panel 40 is located on the side of the body 14 in a convenient location from which an operator can control aspects of the vehicle. A secondary control unit 42 is also located in the personnel basket 15 that allows an operator to drive and control the vehicle while standing in the personal basket. The control panel 40 and the secondary control unit 42 are also coupled to a hydraulic system 80 configured to control the movement and position of the boom 16 between a lowered position (
In other embodiments, the steering system 38 can be coupled to steerable rear wheels so the vehicle can be steered by turning the rear wheels relative to the rear axle. In another embodiment, the front wheels and rear wheels are each steerable to allow for a desired range of control and maneuverability of the vehicle. In such an embodiment, the control system 36, the drive system 34, and the steering system 38 can be configured for an all-wheel steering configuration, including a crab-steering configuration.
In the illustrated embodiment, the steering system 38, the control system 36, and the drive system 34 are also configured to limit the maximum operating speed of the vehicle to avoid creating tipping condition in the various vehicle configurations and positions. In one embodiment, the control system 36 includes a programmed or programmable on-board computer configured to monitor the vehicle's speed, boom configuration (including its angular orientation), and the body configuration (including its angular orientation). The control system 36, via the on-board computer, adjusts the vehicle's maximum operating speed in either a forward or rearward direction is limited as a function of the angular orientation of the front wheels 22 and as a function of the boom's position between the lowered and raised positions and the body's position between the extended and retracted positions.
When the front wheels 22 are turned to a maximum angular orientation and/or the boom 16 is in the fully raised position while the body 14 is in the fully retracted position (
The control system 36 and/or the drive system 34 can also be configured to continuously or consecutively adjust the maximum operating speed at which the vehicle can be driven when the boom is raised or lowered to an intermediate position and when the front and rear portions 18 and 24 of the body 14 are longitudinally adjusted to an intermediate position between the extended and retracted positions. For example, the vehicle 10 can have a plurality of position and speed sensors coupled to the control system 36 and/or the drive system 34. When the sensors detect that the boom 16 is being rotated upwardly toward the raised position and that the body 14 is being moved toward the retracted position, the control system can automatically reduce the vehicle's maximum operating speed for that vehicle configuration.
In the illustrated embodiment, the body 14 of the vehicle 10 is longitudinally adjustable between the extended and retracted positions by articulating or otherwise longitudinally moving the body's rear portion 24 relative to the front portion 18.
The body's rear portion 24 in the illustrated embodiment includes a pair of rigid frame rails 50 substantially parallel with the vehicle's longitudinal axis 32. The frame rails 50 are rigidly connected at their rear ends 52 to the rear axle 26 between the rear wheels 28. A mounting member 58 is rigidly attached to a front portion 54 of the frame rails 50, and the mounting member is pivotally attached to one end of a rigid link member 56. The other end of the link member 56 is pivotally connected to a rigid mounting member 60 on the body's front portion 18.
The link member 56 pivots relative to the mounting members 58 and 60 so as to allow the body's rear portion 24 to move longitudinally in the forward or rearward direction relative to the body's front portion 18 and substantially parallel to the vehicle's longitudinal axis 32. When the body 14 is in the fully extended position, the front end portions 54 of the frame rails 50 are spaced rearwardly away from the body's front portion 18, and the link member 56 is in a lowered position. The rear wheels 28 are spaced apart from the front wheels 22 by a first distance to define an extended wheelbase configuration. When the body 14 is in the retracted position, as shown in
In the illustrated embodiment, the length of the wheelbase 30 and the associated position of the body's front and rear portions 18 and 24 are directly related to the angular orientation of the boom 16. In the illustrated embodiment, the boom 16 has extendible telescoping boom sections 62 pivotally mounted at the boom's proximal end 64 to a pivot mount 66 rigidly fixed on the body's front portion 18 adjacent to the mounting member 60. The boom 16 also has a reinforced intermediate connector 68 above the pivot mount 66 and pivotally connected to the mounting member 58 on the frame rails 50. The resulting direct interconnection between the boom 16 and the body's rear portion 24 restricts lateral movement of the boom's telescoping sections 62 relative to the body 14 and the longitudinal axis 32. Accordingly, the pivoting movement of at least the boom's telescoping sections 62 is in a plane substantially parallel to the vehicle's longitudinal axis 32.
The direct interconnection between the boom 16 and body's rear portion 24 at the frame rails 50 via the link member 56 causes simultaneous movement of the boom 16 and the body's front and rear portions 18 and 24. When the vehicle's body 14 is in the extended position with the long wheelbase 30, the boom 16 is securely retained in the lowered position. As the body's rear portion 24 is moved forwardly (and upwardly because of the pivoting motion of the link member) to shorten the wheelbase 30, the boom 16 is automatically pivoted upwardly about the pivot mount 66 and moves toward the raised position. Accordingly, when the body 14 is in the intermediate position between the extended and retracted positions, the boom 16 is also in the intermediate position between the raised and lowered positions. When the body 14 is in the fully retracted position, the boom 16 is in the fully raised position.
In the illustrated embodiment, the vehicle 10 includes a hydraulic system 80 coupled to the control system 36 and configured to control movement of the body 14, the boom 16, and the personnel basket 15. The hydraulic system 80 can also be coupled to the steering system 38 and configured to allow an operator to control the angular orientation of the front wheels 22 (and/or the rear wheels 28). The hydraulic system 80 includes a plurality of lift cylinders 82 coupled to a hydraulic fluid source by a plurality of hydraulic lines or hoses 86 (
As best seen in
In the illustrated embodiments, the main lift cylinder 100 is configured to extend and retract to move the body 14 and the boom 16. As the main lift cylinder 100 is actuated and extended, the main lift cylinder pushes the boom 16 toward the raised position. The body's rear portion 24 is simultaneously drawn forwardly toward the body's front portion 18, thereby decreasing the length of the vehicle's wheelbase 30. As the main lift cylinders 100 is retracted, the main lift cylinder pulls the boom 16 toward the lowered position. The body's rear portion 24 is simultaneously pushed rearwardly away from the body's front portion 18 to increase the length of the vehicle's wheelbase 30.
In the illustrated embodiment, the control system 36 can be configured to activate front brakes on the front wheels 22 only, so the body's front portion 18 remains stationary as the rear portion 24 is drawn toward the front portion. In other embodiments, rear brakes can be applied to the rear wheels 28 so that the front wheels 22 can roll as the body's front portion 18 is drawn toward the body's rear portion 24 when the body 14 is moved toward the retracted position. In another embodiment, both the front and rear wheels 22 and 28 can be free to roll when the main lift cylinder 100 is activated.
The hydraulic system 80 of the illustrated embodiment includes a master cylinder 90 coupled to one or more slave cylinders (not shown) and configured to help keep the personnel basket 15 level during movement of the boom 16. The master cylinder is pivotally connected at one end to the mounting member 60 on the body's front portion 18. In the illustrated embodiment, the master cylinder 90 is connected to the mounting member 60 forward of the pivotal connection between the mounting member and the link member 56 discussed above. In this arrangement, the master cylinder 90 does not impede movement of the link member 56 as the body moves between the extended and retracted positions. The other end of the master cylinder 90, which is the end of a rigid actuator rod 98, is pivotally connected to the reinforced intermediate connector 68 on the boom 16. This connection is just below the connection between the intermediate connector 68 and the mounting member 58 on the body's rear portion 24. The master cylinder 90 is also positioned to avoid impeding motion of the boom 16 relative to the body's rear portion 24 during movement between the extended and retracted positions. The master cylinder 90 is compressed or extended as the boom 16 moves between the raised and lowered positions, thereby driving hydraulic fluid to or from the one or more slave cylinders.
The hydraulic system 80 also includes one or more other lift cylinders 112 coupled to the boom's telescoping sections 62 to extend and retract the boom 16. Laterally rotatable cylinders 114 are also coupled to the boom's jib 72 and the personnel basket 15 to control the lateral movement of these components. A jib cylinder (not shown) can also be used to control the vertical movement of the jib 72. The hydraulic system 80 is also operatively coupled to the secondary control unit 42 in the personnel basket 15 so an operator can control the vehicle's movement via the hydraulic system from within the personnel basket.
As described above and shown in
If the boom's telescoping sections 62, the jib 72, and/or the personnel basket 15 need to be moved to a position beyond the vehicle's reach, the tight steering and turning radius 74 of the vehicle 10 allows the operator to easily and quickly reposition the vehicle within reach of the desired location. The vehicle maintains its stability during such repositioning because of the direct relationship between the length of the wheelbase 30 and the position of the boom. The vehicle also maintains its stability because the control system 36 can limit the maximum operating speeds and positions of the vehicle for various vehicle configurations to ensure the vehicle will not move into a configuration highly susceptible of tipping. Accordingly, the vehicle 10 provides for increased maneuverability, particularly when the boom is in the raised position. This increased maneuverability also enables the vehicle to perform without using a conventional turntable attached to the boom.
As best seen in
In another embodiment, the vehicle 10 can include an adjustable counterweight assembly attached to the body 14. The adjustable counterweight assembly could include vertically translatable counterweights and a lift mechanism that raises or lowers the counterweights as the body is adjusted to decrease or increase the length of the wheelbase 30. This adjustable counterweight system could connect to the control system so the counterweights, the body, and the boom all move simultaneously as the boom is raised or lowered and as the wheelbase is extended or retracted.
The lower center of gravity provides for increased stability of the vehicle 10 so that less counterweight is needed. Accordingly, the vehicle will be lighter, easier, and less expensive to manufacture. The lighter vehicle also allows for a construction that can use lighter duty motors to drive the vehicle. Alternatively, the lighter vehicle can result in an increase in efficiency of the electric or internal combustion motors of the drive system. As a result, the vehicle can be less expensive to manufacture and/or to operate without sacrificing performance of the vehicle.
In one embodiment, the vehicle 10 can also include sensors that detect whether the vehicle is in a tipped orientation relative to horizontal, which may occur if the vehicle is on uneven ground. The control system 36 can be coupled to the sensors to detect a tipped condition and thereby restrict how far the boom 16 may be extended or how far the jib 72 can be pivoted laterally relative to the longitudinal axis without creating a risk of tipping.
From the foregoing, it will be appreciated that specific embodiments of the invention have been described herein for purposes of illustration, but that various modifications may be made without deviating from the spirit and scope of the invention. For example, in one embodiment, the front and rear portions 18 and 24 of the body 14 can be configured to move longitudinally relative to each other as the boom moves between the raised and lowered positions. This longitudinal movement can be an axially-directed movement rather than the pivoting movement created by the rigid link member 56 discussed above. In another embodiment, the vehicle 10 can include laterally extendible axles and wheels to increase the width of the vehicle's track if additional lateral stability is desired. Accordingly, the invention is not limited except as by the appended claims.
