Land vehicles – Wheeled – Articulated vehicle
Reexamination Certificate
1998-12-24
2001-08-14
Hurley, Kevin (Department: 3611)
Land vehicles
Wheeled
Articulated vehicle
C280S408000
Reexamination Certificate
active
06273447
ABSTRACT:
FIELD OF THE INVENTION
This invention pertains to a trailer extension support dolly designed for attachment between a towing vehicle and a trailer to partially support the tongue weight of the trailer. The trailer extension support dolly is equipped with one or more support wheel(s) which are free castering, with each of the support wheels being supported by a stub axle which is attached to a pivotable axle support bracket. A linear actuator is provided for selectively pivoting the axle support bracket(s) to change their castor such that the wheel(s) can be selectively made freely castering in either a forward or reverse direction.
BACKGROUND OF THE INVENTION
There are many types of trailers normally pulled by tow vehicles such as automobiles, pick-up trucks, vans, utility trucks, and motor homes. These trailer types include camper trailers, large travel trailers, livestock trailers, boat trailers, enclosed vehicle trailers, flat trailers on which may be used to transport farm machinery, NASCAR-type racing cars, motorcycles and other such equipment, etc. As trailers have become larger, heavier, and varied in design over the years, the support wheels have been moved ever further rearward. While this trend does make the trailer pull straighter and more stable with less sway, however, the negative aspect of this trend is this movement shifts more of the weight of the trailer and its contents to the hitch, thus increasing the tongue weight load applied to the rear of the towing vehicle.
Although it may be conceded that a certain amount of tongue weight on the hitch may be beneficial for traction in slippery conditions to keep the drive wheels from spinning, it should also be pointed out that increasing the tilting moment around the rear axle of the towing vehicle has the effect of decreasing the traction at the steering wheels as well as causing the headlights too shine in beams far to high to be safe. Also, while many tow vehicles have the power to pull a large load, few have the frame strength to safely support a large trailer tongue load applied to the rearmost section of the tow vehicle frame.
It thus becomes necessary to reduce the trailer tongue weight in some circumstances. A number of attempts have been made to make a load carrying dolly which attaches between the tow vehicle and the trailer. An example of such a trailer dolly is found in U.S. Pat. No. 3,345,081 to Hartwig, which is directed to a dolly with a pair of support wheels and horizontal and vertical shock absorbing springs. The wheels are not free castering. U.S. Pat. No. 4,253,679 to Sargent is directed to a trailer dolly with a pair of support wheels and with the trailer hitch mounted forward of the axis of rotation of the support wheels. Each wheel is attached via an independent torsion spring which is adjustable for different trailer weights. Again, the wheels are not free castering. U.S. Pat. No. 4,491,338 to Sheldrake and U.S. Pat. No. 3,888,515 to Winter are dollies which are securely attached to the tow vehicle frame. These require custom installation on each towing vehicle, and attachment and removal is generally complicated. U.S. Pat. No. 5,664,796 to Huyzers is a “vehicle extender” which uses a “single, castor action, load bearing wheel set” which is attached to the extender via a vertical or angled shaft. U.S. Pat. No. 5,382,041 to Keith uses an arm limited dolly that may also scuff tires on the roadway each time the vehicle is turned beyond arm limits. U.S. Pat. No. 5,338,050 to Haire uses a dolly that locks the dolly wheels in a straight forward position during the backing up procedure forcing the tires to scrub the ground if any turning is required causing excessive tire wear. Finally there is a specialty steering dolly-type exemplified by the U.S. Pat. No. 5,531,468 to White, in which the inventor goes to great lengths to provide a steering dolly for insertion between the towing vehicle and the towed vehicle. Again the load carrying wheels do not freely caster, and the device may also be difficult to handle during backing as may be required for parking or the like. The solutions devised by these patents are generally satisfactory in shifting some of the tongue weight away from the tow vehicle and onto the support dolly. However, backing up trailers equipped with these dollies is very difficult since it essentially amounts to the simultaneous backing of two tandem linked trailers. Even in the case of free castering support wheels, the wheels often tend to “scrub” sideways instead of swiveling freely during backing operations.
It is clear, then, that a need exists for an improved trailer support which accepts some of the tongue weight of a trailer, thus shifting it off of the two vehicle. Such a support should have support wheels which freely caster in either forward or reverse directions.
SUMMARY OF THE INVENTION
The present invention is essentially a trailer extension support dolly in which the frame of the dolly is substantially coupled or connected by fasteners, bonding, glueing, or welding to the frame of the trailer. The trailer extension support dolly frame is supported by a pair of articulating, free castering support wheels. The trailer extension support dolly attaches to a trailer between a tow vehicle and the trailer to at least partially support the tongue weight of the trailer. The trailer extension support dolly can be attached to the trailer via a ball and socket connection coupled with a pair of rods which extend between the trailer extension support dolly frame and the trailer hitch bar. Each of the support wheels is mounted on a respective stub axle which is attached to an articulating axle support bracket via a swiveling knuckle to that each wheel is allowed to caster during turning operations. In order to provide proper castering while going either in a forward direction or a reverse direction, the angle of each axle support bracket is adjustable so that the stub axle swivel connection can be selectively angled forward or rearward. With this adjustment, the support wheels can be alternatively, respectively positioned to freely caster during either forward or reverse steering operations.
OBJECTS AND ADVANTAGES OF THE INVENTION
The objects and advantages of the invention include: providing a trailer extension support dolly which safely removes a portion of the trailer tongue weight from a tow vehicle while functioning in both forward and reverse operations exactly as a standard single axle or closely spaced tandem/triple axle trailer would; providing such a trailer extension support dolly which can be connected between a trailer and tow vehicle; providing such a trailer extension support dolly which includes a frame supported by one or more support wheels; providing such a trailer extension support dolly in which the support wheel(s) are attached to respective stub axles which are, in turn, attached to respective axle supports via swivel mounts so that the wheels are permitted to caster during turning operations; providing such a trailer extension support dolly in which the axle support(s) are selectively pivotable relative to the trailer extension support dolly frame so that the angle of each axle support relative to the trailer extension support dolly frame can be adjusted; providing such a trailer extension support dolly with a powered adjuster attached to each axle support which allows the axle support(s) to be selectively adjusted between forward and rearward angles relative to the trailer extension support dolly frame such that the attached wheel(s) freely caster in respective reverse or forward directions; and providing such a trailer extension support dolly which is particularly well suited for its intended purpose.
Other objects and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of this invention.
The drawings constitute a part of this specification and include exemplary embodiments of the present invention an
Fischer Andrew J.
Hurley Kevin
Shughart Thomson & Kilroy P.C.
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