Patent Description:
Terminal tractors are semi-tractor vehicles used for moving semi-trailers about a cargo holding area, a warehouse facility, intermodal facility, or other similar locations. Such vehicles provide an efficient means to rapidly move and reposition such semi-trailers for subsequent operations. These vehicles typically have a small single person cab and operate using a low-power diesel or alternative fuel engine.

Advantageously, such vehicles typically include a fifth wheel coupling for coupling to a kingpin of a semi-trailer. The fifth wheel coupling typically includes an integrated lifting mechanism. This lifting mechanism allows the semi-trailer's legs to remain in their lowered position during movement. Put differently, the fifth wheel coupling can be lifted upwards to connect to the kingpin and to lift the semi-trailer to such an extent that it no longer rests upon its legs. This creates a ground clearance that allows the terminal tractor to then tow the semi-trailer to a desired location.

Such terminal tractors, while a useful expedient for moving semi-trailers as described above, are not without some drawbacks. As one example, such vehicles are typically front wheel steer. As such, terminal tractors have the same turning radius limitations as any other front-wheel steer vehicle. This minimum turn radius of the tractor trailer ultimately dictates how close semi-trailers can be situated to one another, which in turns limits how many semi-trailers may be located in a given area.

Further, such vehicles are typically manually operated and thus must be manned via a human operator. This increases their cost of operation, and also creates a possibility for operator error. As yet another example, the above mentioned lifting mechanisms involve multiple linkages to the fifth wheel coupling. This relative complexity results in the fifth wheel coupling be situated off of the center point between the four wheels of the terminal tractor. This off centering creates a larger than desirable turning radius for the vehicle and thus compounds the turn radius issues mentioned above.

Accordingly, there is a need in the art for a terminal tractor which addresses the above drawbacks to provide a vehicle with an enhanced turning radius and other enhanced operational characteristics. The invention provides such a terminal tractor. These and other advantages of the invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.

In one aspect, the invention provides a terminal tractor which advantageously provides a desirable turn radius by way of a four wheel steering system. An embodiment of a terminal tractor according to this aspect includes a chassis, a first axle carrying a first pair of wheels mounted to the chassis, and a second axle carrying a second pair of wheels mounted to the chassis. This embodiment of a terminal tractor also includes a plurality of drive motors. Each drive motor is associated with each one of the first pair of wheels and with each one of the second pair of wheels, respectively, to rotate said pairs of wheels relative to their associated first or second axle. This embodiment of a terminal tractor also includes a plurality of steering devices. Each steering device is associated with each one of the first pair of wheels and with each one of the second pair wheels, respectively, to independently steer each one of the first pair of wheels and each one of the second pair of wheels. The terminal tractor also includes a controller in communication with said plurality of drive motors and said plurality of steering devices as well as a fifth wheel coupling configured for coupling to a kingpin of a semi-trailer.

In an embodiment according to this aspect, the controller is in communication with said plurality of drive motors and said plurality of steering devices to provide a drive input to each one of the plurality of drive motors and a steering input to each one of the plurality of steering devices.

In an embodiment according to this aspect, the fifth wheel coupling includes a lifting mechanism that is configured to transition a coupling body of the fifth wheel coupling from a lowered position to a raised position and from the raised position to the lowered position by moving the coupling body in a single vertical direction.

The terminal tractor according to the invention also includes a control head that provides at least one of an air brake and an electrical connection for connecting to the semi-trailer. The control head is foldable between upright and collapsed positions.

In an embodiment according to this aspect, the plurality of drive motors are electric drive motors. The terminal tractor may also include a power source carried by the chassis that provides power to said plurality of drive motors, plurality of steering devices, and controller. The power source may for non-limiting example be an electric power source.

In an embodiment according to this aspect, each one of the plurality of steering devices includes a servo motor associated with each one of first pair of wheels and each one of the pair of second wheels, respectively, such that the first pair of wheels and second pair of wheels are independently steerable.

In another aspect, the invention provides a terminal tractor which advantageously utilizes an on-board controller to operate the terminal tractor such that a human operator on board on the terminal tractor is not required. An embodiment of a terminal tractor according to this aspect includes a chassis, a first axle carrying a first pair of wheels mounted to the chassis, and a second axle carrying a second pair of wheels mounted to the chassis. This embodiment also includes a plurality of drive motors and a plurality of steering devices. A controller is in communication with the plurality of drive motors and the plurality of steering devices to provide a drive input to each one of the plurality of drive motors and a steering input to each one of the plurality of steering devices. This embodiment also includes a fifth wheel coupling configured for coupling to a kingpin of a semi-trailer.

In an embodiment according to this aspect, each drive motor is associated with each one of the first pair of wheels and with each one of the second pair of wheels, respectively, to rotate said pairs of wheels relative to their associated first or second axle.

In an embodiment according to this aspect, each steering device is associated with each one of the first pair of wheels and with each one of the second pair wheels, respectively, to independently steer each one of the first pair of wheels and each one of the second pair of wheels.

In an embodiment according to this aspect, the controller may be configured to operate the terminal tractor autonomously, or operate the terminal tractor based upon input commands provided by a user remotely.

In yet another aspect, the invention provides a terminal tractor with a fifth wheel coupling that advantageously employs a vertically acting mechanism having a small package size, which permits locating the fifth wheel coupling, and more particularly a coupling point of the fifth wheel coupling at a center of the terminal tractor. An embodiment of a terminal tractor according to this aspect includes a chassis, a first axle carrying a first pair of wheels mounted to the chassis, and a second axle carrying a second pair of wheels mounted to the chassis. This embodiment also includes a plurality of drive motors and a plurality of steering devices. A controller is in communication with said plurality of drive motors and said plurality of steering devices. This embodiment also includes a fifth wheel coupling configured for coupling to a kingpin of a semi-trailer. The fifth wheel coupling includes a lifting mechanism that is configured to transition a coupling body of the fifth wheel coupling from a lowered position to a raised position and from the raised position to the lowered position by moving the coupling body in a single vertical direction.

In an embodiment according to this aspect, each drive motor is associated with each one of the first pair of wheels and with each one of the second pair of wheels, respectively, to rotate said pairs of wheels relative to their associated first or second axle. Each steering device is associated with each one of the first pair of wheels and with each one of the second pair wheels, respectively, to independently steer each one of the first pair of wheels and each one of the second pair of wheels.

In an embodiment according to this aspect, the controller is in communication with said plurality of drive motors and said plurality of steering devices to provide a drive input to each one of the plurality of drive motors and a steering input to each one of the plurality of steering devices. In an embodiment according to this aspect, the terminal tractor may include a power source carried by the chassis that provides power to said plurality of drive motors, plurality of steering devices, and controller.

Turning now to the drawings, <FIG> illustrates an automated terminal tractor <NUM> which advantageously provides a highly mobile and modular platform that presents enhanced turning and fifth wheel functionality. While shown with various cosmetic coverings and features, such coverings and features are entirely optional. As may be surmised from inspection of <FIG>, terminal tractor <NUM> is a wheeled vehicle. As will be explained in greater detail below, terminal tractor <NUM> utilizes a four wheel steering configuration to provide a highly mobile platform capable of maneuvering in small spaces. Terminal tractor <NUM> also utilizes a fifth wheel coupling which is movable in a single vertical direction by utilizing a highly compact and direct acting lifting mechanism. These features, among others, provide distinct advantageous over prior designs which do not include such four wheel steering capabilities or utilize more complex lifting mechanisms for their fifth wheel couplings.

With particular reference to <FIG>, terminal tractor <NUM> includes a chassis <NUM>, a first pair of wheels <NUM>, and a second pair of wheels <NUM> as shown. As will explained below, a drive motor is associated with each one of the wheels <NUM>, <NUM> to independently provide a drive input to the same. A fifth wheel coupling <NUM> is also mounted to chassis <NUM> and is used to connect to a kingpin of semi-trailer.

Terminal tractor <NUM> may also include a control head <NUM> which provides connection points to at least one of an air brake line or an electrical connection of a semi-trailer connected to terminal tractor <NUM>. Control head <NUM> may be foldable in direction <NUM> from its stowed position shown in <FIG> to an upright position such that it has a generally vertical presentation. Control head <NUM> may also be moved in direction <NUM> from the upright position to its stowed position. This folding functionality may be achieved by any known mechanical expedient such as motors and optionally associated linkages.

Control head <NUM> may also include communication devices such as antenna, transmitters, and receiving for communicating with any other devices. For non-limiting example, control head <NUM> may contain the componentry necessary for receiving GPS signals, as well as the componentry necessary for communicating with a network, e.g. a cellular or local area network using any known means of communication over such a network. Control head <NUM> may also package some or all of the sensor devices needed for the autonomous or remote operation of terminal tractor <NUM>, such as vision systems, anticollision systems, sonar devices, etc. Still further, control head <NUM> may include solar power panels for charging an onboard power source <NUM>. It is also contemplated that all of the componentry of control head <NUM> may be housed elsewhere in terminal tractor <NUM> in those embodiments which do not include a control head.

A power source <NUM> may also be connected to chassis <NUM>. This power source may for example be an electric power source using batteries, nitrogen, hydrogen, fuel cells, or any combination thereof. Power source <NUM> is modular in that it may be readily removed and replaced from terminal tractor <NUM> in much the same way a battery is removable and readily replaceable from a device. To that end, power source <NUM> may include one or more submodules which mount to chassis at different locations <NUM>. Further power source <NUM> may include provisions for connecting to a charging station to recharge it. It is also contemplated that terminal tractor <NUM> may draw power via induction using an electric road or rail configuration.

Turning now to <FIG>, the same shows terminal tractor <NUM> with its wheels <NUM>, <NUM> and cosmetic coverings removed. Chassis <NUM> functions as a central frame and may be made of a high strength steel or other allow to present a light yet rigid frame. Chassis <NUM> may include an internal cavity or region <NUM>.

A controller <NUM> may be housed in this internal cavity <NUM>. "Controller" as used herein is meant to include all of the firmware, software, and hardware needed to control and operate the terminal tractor <NUM>, including but not limited to its autonomous or remote operability. Controller <NUM> is designed to communicate with all the sensors of terminal tractor <NUM> necessary to effectuate its autonomous operation as inputs, and send control signals as outputs.

Controller <NUM> also incorporates all of the means necessary for communicating with users as well as other machines. As such, controller <NUM> may include artificial intelligence programming to achieve such ends. As a non-limiting example, controller <NUM> may include programming allowing it to receive a job or command list, such as a list of pickup and subsequent drop off locations for semi-trailers. Controller <NUM> is operable to autonomously control terminal tractor <NUM> to execute the details of such a command list. In operating as such, controller <NUM> is operable to interpret the information it receives from the various sensory systems of terminal tractor <NUM>. Controller <NUM> is designed to be modular in that it may be readily removed from chassis <NUM> for updates and maintenance.

A first axle <NUM> for carrying the first pair of wheels <NUM> (see <FIG>) is mounted to chassis <NUM>. "Wheel" or "wheels" as used herein includes a single wheel, or a multiple wheel configuration. For example, the first pair of wheels <NUM> is mounted to first axle <NUM> such that one wheel <NUM> is at one end of first axle <NUM>, while the other wheel <NUM> is at the other end of first axle <NUM>. Each wheel at each end may encompass a single wheel, or a multiple wheel (e.g. a dual wheel) configuration.

In an identical fashion, a second axle <NUM> is mounted to chassis <NUM> and is used to carry the second pair of wheels <NUM>. Axles <NUM>, <NUM> may be embodied for example as pendulum axles to ensure that a terminal tractor <NUM> maintains good ground contact using all four wheels <NUM>, <NUM>, despite uneven terrain.

As may be seen in <FIG>, a plurality of drive motors <NUM> are also provided. A drive motor <NUM> is respectively associated with each wheel <NUM>, <NUM> as shown. The drive motors draw power from power source <NUM> and are controlled by controller <NUM> to ultimately rotate their respective wheel <NUM>, <NUM> about its respective axle <NUM>, <NUM>. Drive motors <NUM> may be embodied by any rotary electric drive motor. Additionally, one or more radiators or other similar cooling devices <NUM>, <NUM> may be provided on chassis <NUM> to provide cooling to terminal tractor <NUM>.

Turning now to <FIG>, as mentioned above, terminal tractor <NUM> includes a fifth wheel coupling <NUM> for connecting to a kingpin of a semi-trailer. Fifth wheel coupling includes a lifting mechanism described below, as well as a coupling body <NUM> which mates with the aforementioned kingpin. Coupling body <NUM> may also provide a mounting location for the above discussed control head <NUM>. Alternatively, control head <NUM> may mount to chassis <NUM>.

Lifting mechanism is operable to raise and lower coupling body in a single vertical direction generally denoted by axis <NUM> shown in <FIG>. By "single vertical direction" it is meant that the coupling body <NUM>, and more particularly a coupling point <NUM> (see <FIG>) moves linearly up and down with a single component directional vector. This is a departure from prior designs which typically move their coupling body in a directional vector having multiple directional components.

Indeed, many existing designs move the coupling body along an arcuate path. Such motion requires a more complex mechanism, and results in the coupling point of the coupling body being offset from the center defined between the wheels of such existing terminal tractors. Due to this offset, such existing terminal tractors inherently have a larger turning radius when connected to a semi-trailer. In other words, more front end clearance is needed for the terminal tractor to turn as it pulls the semi-trailer.

In the illustrated embodiment, the lifting mechanism may achieve such purely vertical motion along axis <NUM> by way of a linear actuator acting directly underneath coupling body <NUM> to move the same vertically up and down. Additionally, an additional mechanism may be employed to shift coupling body <NUM> along axis <NUM>. Still further, coupling body <NUM> may be rotatable about axis <NUM> to reposition the opening of coupling body for receiving the kingpin, and also rotatable about an axis normal to the plane of axes <NUM>, <NUM> to allow coupling body <NUM> to tilt.

Still referring to <FIG>, wheels <NUM>, <NUM> may incorporate any type of tire, the selection of which will depend largely upon operational environment. As one non-limiting example, these tires may be non-air tires which provide enhanced durability and traction and are lower in maintenance requirements than their air filled counterparts. A cone design may also be employed which improves four wheel steering capabilities and allows for excellent turning angles.

Turning now to the exploded view illustrated in <FIG>, lifting mechanism <NUM> is generally illustrated as a linear cylinder lifting mechanism, e.g. a linear actuator. This may be an electric, hydraulic, or pneumatic actuator. In the case of hydraulics or pneumatics, terminal tractor <NUM> will also include a hydraulic or pneumatic system. As mentioned above, this lifting mechanism <NUM> acts directly on coupling body <NUM> to linearly move coupling point <NUM> in a single vertical direction.

Terminal tractor <NUM> also includes a plurality of steering devices <NUM>, two of which are shown exploded relative to their associated wheels <NUM>, <NUM> and associated axles <NUM>, <NUM>. Indeed, each wheel <NUM>, <NUM>, includes its own local steering device <NUM> in the same manner as each wheel includes its own drive motor <NUM>. These steering devices may for example be servo motors operable to turn its respectively associated wheel <NUM>, <NUM> relative to that wheel's <NUM>, <NUM> associated axle. The steering devices <NUM> receive steering input commands from controller <NUM> and are independently movable relative to one another. As such, it is possible for each wheel <NUM>, <NUM> to have a different orientation thus opening a variety of steering capabilities.

Indeed, and turning now to <FIG>, each wheel <NUM>, <NUM> has a center point <NUM>. The steering devices <NUM> are operable to rotate each wheel about its center point <NUM> in directions <NUM>, <NUM> as shown. Also as will be discussed below, a center <NUM> of coupling point <NUM> of coupling body <NUM> is centered between the first pair of wheels <NUM> and second pair of wheels <NUM> in the y direction in <FIG>, and centered between the first pair of wheels <NUM> and second pair of wheels in the x direction in <FIG>.

<FIG> illustrates a basic front wheel steering operation of terminal tractor <NUM>. The first pair of wheels are oriented in the direction shown, allowing for travel along curved path <NUM>. However, due to the above introduced four wheel steering capabilities, it is also possible to have a much tighter turn radius than curved path <NUM>. Indeed, turning now to <FIG>, by independently positioning wheels <NUM>, <NUM> as shown, terminal tractor <NUM> can make a much tighter turn represented by curved path <NUM> in <FIG>.

Still further, zero-point turning is also possible as is shown in <FIG>. Indeed, wheels <NUM>, <NUM> may be oriented as illustrated to allow terminal tractor <NUM> to rotate in place about fifth wheel coupling <NUM> (see <FIG>) as is represented by directional arrows <NUM>. It is also possible for terminal tractor <NUM> to employ a crab-style steering as is shown in <FIG> wherein a front of terminal tractor <NUM> is not in line with the direction of travel <NUM> as is shown. Such a configuration is particularly useful for connecting to a kingpin while being prepositioned in a turning direction.

<FIG> illustrate the above described four wheel steering functionality in the context of a semi-trailer <NUM>. In <FIG>, terminal tractor <NUM> (schematically illustrated) has approached semi-trailer <NUM> in direction <NUM> as it is resting on its legs <NUM>. In this configuration, terminal tractor <NUM> is connected to the kingpin of semi-trailer <NUM>.

In <FIG>, wheels <NUM>, <NUM> of terminal tractor <NUM> have moved to their zero-point steering configuration to allow terminal tractor <NUM> to rotate in direction <NUM> about its fifth wheel coupling. In <FIG>, terminal tractor is now in the direction of intended movement. In <FIG>, terminal tractor <NUM> begins moving in direction <NUM>, ultimately causing semi-trailer <NUM> to begin to turn in direction <NUM> as shown.

The aforementioned centered location of fifth wheel coupling <NUM> is schematically illustrated in <FIG>. As may be seen in this view, the center <NUM> of each of the first pair of wheels <NUM> are spaced apart in the y direction a distance B, while the center <NUM> of each wheel <NUM> is spaced from center point <NUM> a distance of B/<NUM>. Similarly, the centers <NUM> of the first pair of wheels are in line with one another and spaced from the centers <NUM> of the second pair of wheels <NUM> (also in line with one another) in the x direction at distance D, while the centers of the first pair of wheels <NUM> are spaced from center point <NUM> a distance D/<NUM> in the x direction. The same holds true for the centers <NUM> of wheels <NUM> in that they are also spaced from center point <NUM> at a distance D/<NUM> in the x direction.

No language in the specification should be construed as indicating any nonclaimed element as essential to the practice of the invention.

Claim 1:
A terminal tractor, comprising:
a chassis;
a first axle mounted to the chassis, the first axle carrying a first pair of wheels;
a second axle mounted to the chassis, the second axle carrying a second pair of wheels;
a plurality of drive motors, wherein each drive motor is associated with each one of the first pair of wheels and with each one of the second pair of wheels, respectively, to rotate said pairs of wheels relative to their associated first or second axle;
a plurality of steering devices, wherein each steering device is associated with each one of the first pair of wheels and with each one of the second pair wheels, respectively, to independently steer each one of the first pair of wheels and each one of the second pair of wheels;
a controller in communication with said plurality of drive motors and said plurality of steering devices; and
a fifth wheel coupling configured for coupling to a kingpin of a semi-trailer, characterized in that the tractor further comprises
a control head, said control head providing at least one of an air brake and an electrical connection for connecting to said semi-trailer, wherein said control head is foldable between upright and collapsed positions.