Patent Application
20060175799
Not Applicable
Not Applicable
1. Field of the Invention
The present invention relates to on-road trailers for towing behind a motor vehicle, and more particularly to utility trailers that have a single wheel.
2. Description of the Related Art
Utility trailers are commonly towed behind motor vehicles, such as pick-up trucks and automobiles, to transport relatively various kinds of loads. Most utility trailer trailers are designed for a specific application: for example, boat trailers, camping trailers, trailers with pods, and flat bed trailers. It is also known to utilize single-wheel utility trailer trailers for relatively light weight loads to reduce the cost of the device. The single wheel generally is displaced rearward of the trailer kingpin by which the trailer is coupled to the motor vehicle and that positioning enables the wheel to follow turns. To allow a motor vehicle with a single-wheel trailer to be driven backwards easily, it is common to use a double hitch which provides a non-articulated coupling.
A typical single wheel utility trailer has a fixed rectangular bed and removable side walls. The single wheel is fixedly mounted beneath a longitudinal frame of the bed and cannot caster. Thus the wheel tends to skid laterally during a turn. Alternatively, a caster mounted wheel, as described in U.S. Pat. No. 4,645,230, can be used to follow the towing vehicle through turns.
Although the bed of a utility trailer usually is only a foot or two above the ground the load being carried must be lifted onto and off of the trailer. One frequent use of a utility trailer is to transport a garden tractor, snowmobile or other article with wheels. Such transport requires the attachment of ramps to enable the article to be driven on and off the trailer. The ramps then must be carried on the utility trailer during the transport and stored when not required. Therefore, it is desirable to facilitate the loading and unloading of utility trailers, especially in a manner that does not require ramps.
A utility trailer for towing by a motor vehicle comprises a bed with a platform for supporting a load that is carried by the utility trailer while traveling on a road. A coupling is moveably connected to the platform for mating with a hitch on the motor vehicle and a carriage frame also is moveably connected to the platform. At least one wheel is attached to the carriage frame to support the utility trailer on the road. An actuator assembly moves the platform with respect to the coupling and the carriage frame to raise and lower the platform with respect to the road.
The actuator assembly enables the platform to be lowered against the road for loading and unloading the trailer. This allows articles with wheels, such as garden tractors and snowmobiles to be driven on and off the trailer platform. The actuator assembly raises the platform to enable the trailer to travel on the road when towed behind a motor vehicle.
In one embodiment of the trailer, the carriage frame is slideably attached to the rear of the trailer platform and a first linear actuator produces motion there between. The coupling is similarly slideably attached to the front of the platform and a second linear actuator produces motion between those components. Operating the second linear actuator, while the platform is on the road, adjusts the height of the coupling to mate with a hitch on a motor vehicle. After that connection has been made, operating both linear actuators in unison raises the platform off the rod.
A two wheeled trailer incorporating this novel platform elevating mechanism also is described.
With initial reference to
The rear side of the bed 12 has a pair of vertical posts 22 extending upward from the under frame 16, spaced apart and centered about the middle of that rear side. The rear posts 22 form a first frame 23. One or more cross members may extend between the two vertical rear posts 22 for strength. The carriage frame 15 is coupled to these rear posts in a manner that allows vertical motion there between. With additional reference to
A first actuator 40, such as a motor driven, ball-screw linear actuator, is connected between the carriage frame 15 and the bed 12 of the trailer. The actuator 40 has a DC motor 42 that is electrically powered from the motor vehicle that tows the trailer 10, however hydraulically powered motors or a cylinder/piston assembly can be used as the actuator. A hand operated actuator, similar to those conventionally used on trailer hitches, also may be employed. In the illustrated embodiment, the motor 42 of the actuator 40 is secured to the carriage frame 15 with the actuator screw shaft 44 extending downward from the motor and having a remote end connected to a bracket 46 on the rear side of the under frame 16. As will be described, the actuator 40 produces bidirectional, vertical motion between the trailer bed 12 and the carriage frame 15. Depending upon the polarity of the electricity applied to the motor 42, the screw shaft 44 is retracted into or extended from the motor, thereby producing up or down motion.
With reference to
With specific reference to
Hook plates 72 are welded to the ends of a cross member 73 of the coupling bar 61. The opening of each hook plate 72 receives an upper pin 74 that is inserted into one of a series of vertically spaced apertures 75 in one of the vertical legs 54 of the trailer coupling 14. Upon that engagement, a lower pin 76 is inserted in another one of the apertures 75 beneath the hook plate 72. The spacing between adjacent apertures 75 is such that with the pins 74 and 76 in place, the hook plates 72, and thus the coupling bracket 60, can not the removed from the vertical legs 54. This secures the components of the trailer coupling 14 together in a manner that allows the height of the coupling bracket 60 to be adjusted to accommodate variation in height of the hitch receptacle 62 on different vehicles.
The adjustment is made by inserting a detached coupling bracket 60 into the hitch receptacle 62 on a motor vehicle. The vehicle is moved backward until the hook plates 72 are between the vertical legs 54 of the trailer coupling 14. The upper pins 74 then are inserted into the vertical leg apertures 75 that are immediately above the hook plates 72 and the vertical legs 54 are lowered, as will be described, until those pins rest in the openings in the hook plates. The lower pins 76 are then inserted into the leg apertures 75 that are immediately below the hook plates 72.
Referring again to
The present mechanism for raising an lowering the bed of a trailer also can be used on two-wheeled trailer, such as trailer 80 in
The coupling 90 at the front of the bed 12 is able to slide vertically along the front posts 50 when driven by another actuator 92. The coupling 90 has a bracket 94 with a conventional socket 96 that is adapted to receive the ball of a standard trailer hitch. Because the trailer 80 in
The foregoing description was primarily directed to a preferred embodiment of the invention. Although some attention was given to various alternatives within the scope of the invention, it is anticipated that one skilled in the art will likely realize additional alternatives that are now apparent from disclosure of embodiments of the invention. Accordingly, the scope of the invention should be determined from the following claims and not limited by the above disclosure.
