Patent Application
20050263966
1. Field of the Invention
This invention relates to a wheeled conveyance having at least one tandem axle wheel assembly which replaces a traditional single axle wheel. More particularly, the invention relates to a tandem axle wheel replacement system having wheels which swivel.
2. Description of Related Art
It is known that a tandem axle wheel replacement allows the wheels to traverse an obstacle while lifting the center of the tandem axle assembly only one half of the obstruction height. A single conventional wheel and axle must rise to the full height of the obstacle as it passes over it. The tandem axle wheel replacement requires half the static horizontal force to traverse an obstruction compared to a single conventional wheel. That is, one half the energy is required for each wheel of the tandem axle wheel replacement to ride over an obstacle using a tandem axle when compared to a single axle with the same wheel.
Unfortunately, existing tandem axle mounted wheels are fixed and do not swivel freely. Therefore existing tandem axle mounted wheels drag sideways when rotated about a substantially vertical axis, inhibiting forward motion of the wheels and thereby limiting access and mobility of a wheeled conveyance and, in some instances, the operator thereof.
Accordingly, it is one object of this invention to provide an improved tandem axle wheel replacement for a wheeled conveyance.
It is another object of this invention to provide an improved tandem axle wheel replacement for a wheeled conveyance having swivel wheels which do not inhibit forward motion.
It is another object of this invention to provide an improved tandem axle wheel replacement for a wheeled conveyance which requires reduced static horizontal force to pass over an obstacle.
It is another object of this invention to provide an improved wheeled conveyance providing greater mobility and access for the operator thereof.
These and other objects of this invention are addressed by an improved tandem axle wheel replacement for a wheeled conveyance having swivel wheels. The present invention helps eliminate abrupt jarring or stopping which happens when regular wheeled conveyances, such as walkers, wheeled-chairs, wheeled carts, or the like, either powered or un-powered, encounter obstacles to the forward motion of their wheels. Thus, the present invention makes the wheeled conveyances safer for the rider and reduces the risk of injury and the breaking or jarring of any occupant or contents of the wheeled conveyances.
The present invention may also provide increased access and mobility by enabling the traversal of obstacles which would otherwise block forward motion by permitting a wheeled conveyance to stably maneuver over obstacles smoothly and with less effort in both frontal impacts and angular impacts with obstacles.
In one exemplary embodiment of this invention, the tandem axle wheel replacement includes a double set of tandem axle assemblies, thereby lessening the static horizontal force required to pass over an obstacle to twenty five percent (25%) of the force required by a single conventional wheel.
These and other objects and features of the invention will be better understood from the following detailed description taken in conjunction with the appended claims and drawings.
Referencing
The tandem axle wheel replacement 13 also comprises a support structure 29 which serves as a means for attachment of the carriage 15 to a wheel-supported body, i.e., a wheeled conveyance, in this instance, a forward leg of the illustrated chair 11. The support structure 29 is rotatably attached to the carriage 15 by a journaled attachment 31 thereby allowing the carriage 15 to pivot about the journaled attachment 31, thus allowing vertical movement of the wheels 17, 21, or 35, 37, as indicated by the arrow 33.
Referring to
The first secondary carriage 47 holds a first wheel 55 with a first axle 56 and a second wheel 57 with a second axle 58. The first and second wheels 55, 57 are mounted by first and second casters 59, 61, respectively, which are anchored adjacent the longitudinal ends of the first secondary carriage 47. The second secondary carriage 49 holds a third wheel 63 with a third axle 64 and a fourth wheel 65 with a fourth axle 66. The third and fourth wheels 63, 65 are mounted by third and fourth casters 67, 69, respectively, which are anchored adjacent the longitudinal ends of the second secondary carriage 49.
As is the case in the single tandem axle assemblies of
The double tandem axle wheel replacement 43 also comprises a support structure 71 which serves as a means for attachment of the primary carriage 45 to a wheeled conveyance, again in this instance, a forward leg of the illustrated chair 11. The support structure 71 is rotatably attached to the primary carriage 45 by ajournaled attachment 73 thereby allowing the primary carriage 45 to pivot about the journaled attachment 73, thus allowing vertical movement of the secondary carriages 47,49 and their wheels 55, 57, 63, 65, as indicated by the arrow 75.
Referring to
While in the foregoing specification this invention has been described in relation to certain preferred embodiments thereof, and many details have been set forth for purpose of illustration, it will be apparent to those skilled in the art that the invention is susceptible to additional embodiments and that certain of the details described herein can be varied considerably without departing from the basic principles of the invention.
This application claims the benefit of U.S. Provisional Application No. 60/575,886, filed 01 Jun. 2004.
| Number | Date | Country | |
|---|---|---|---|
| 60575886 | Jun 2004 | US |
