Motor vehicles – Steered by walking attendant
Reexamination Certificate
2000-03-20
2001-08-21
Johnson, Brian L. (Department: 3618)
Motor vehicles
Steered by walking attendant
C180S014100, C180S125000, C280S490100, C280S405100, C280S407000
Reexamination Certificate
active
06276469
ABSTRACT:
BACKGROUND
1. Field of the Invention
This invention applies to transporters concerned with guidance and propulsion of heavy loads from place to place about the floor. In this industry, load levitates upon a pressurized plenum cushion of air during movement. An unrelated industry uses a tractor that includes a similar piston weight lifting structure to that of this invention, but is used for a different purpose. The purpose of the tractor lifting device in that industry is to lift the front end of a mobile home trailer, fifth wheel tailer, or boat trailer up off their rest frame for wheeling about by tractor. This industry is different from the industry of my invention for the primary reason that the loads to be moved are not fluid plenum levitated, but instead are supported by a trailer with wheels. An example of an invention in this other industry includes that disclosed in U.S. Pat No. 3,995,876 by Ronne, Dec. 7, 1976.
BACKGROUND
2. Description of the Prior art
Prior art transporters in the industry of this invention, utilize only one motor powered drive wheel to propel load. Attachment arms connecting load to transporter are long and complex. One such example appears in Air Caster Corp brochure 106. Another invention example was disclosed in U.S. Pat. No. 3,831,708 by Terry, Aug. 27, 1974. The single drive wheel structure is quite durable to sustain considerable downward forces and high friction force against the floor. The single drive wheel is thick, includes rugged bearings, and is made from expensive soft rubber like material on a metal hub much like that of the wheel of a motor scooter. All prior art transporters are heavy in the range of several hundred pounds supporting adequate drive wheel pulling traction. The use of a single drive wheel in all prior art transporters is the inventor's method to facilitate steering by avoiding multiple drive wheel sliding problems while turning. To date, no transporters have attempted to use multiple powered drive wheels that include differentials or disconnecting clutching means probably because the cost and size would be prohibitive. These prior art transporters include several structural deficiencies because:
i. the attachment arm design is complex and expensive
ii. the attachment arm length between the transporter and load is too long for sharp steering
iii. they use an expensive single drive wheel
iv. the transporter is very heavy.
These transporters cost much more than they need to for the job they perform. Transporter weight makes them difficult and inconvenient to move from one factory area to another point of use. Transporter turning radius around doorways and the like is limited over what it could be for a smaller sized transporter that uses a short arm to connect the load.
The object of my invention is to eliminate the objections noted above in connection with known systems of this character. My invention provides a short connecting arm, the ability to steer using multiple drive wheels, is light weight, and includes excellent traction control.
SUMMARY OF THE INVENTION
My invention contributes a propelling and guiding transporter to the industry of air bearing levitated heavy loads with unique and improved features. Prior art transporters were heavy, with long attachment distances between transporter and load, and propel using only one drive wheel. These features rendered the transporters expensive, large in size, unable to make sharp turns around doorways, and their heavy weight made them difficult to relocate to their point of use. My invention includes a unique structure for this industry that eliminates the above objections.
My transporter has lightweight as a key objective. It is hundreds of pounds lighter than transporters of prior art. A human operator can lift and move my transporter to its point of use without powering up. However, the primary objective is that my transporter can have a multitude of drive wheels all connected to a motor simultaneously. The light weight was key to meet this objective in that the connected drive wheels can slide on the floor as the operator steers the transporter. The wheels can slide because drive wheel traction with the floor can be minimal. Without high downward transporter weight, wheel traction is slight. However, high downward force is necessary while transporter is pulling or pushing load. My invention solves this enigma, uniquely to this industry, by adding a force generating means such as a piston and cylinder to the transporter. The pressurized piston can force up onto attachment arm hitch between transporter and load. Its reaction force is downward providing the necessary wheel traction at times when transporter is pulling or pushing the load. Transporter is smaller than prior art transporters performing similar tasks and has a shorter attachment arm to load. Therefore tighter turns are possible with my invention. The transporter of my invention costs less than those of prior art. My invention requires no complex single wheel drive mechanism including costly bearings and robust motor scooter type drive wheel.
REFERENCES:
patent: 3269475 (1966-08-01), Voelker
patent: 3485314 (1969-12-01), Herr
patent: 3770070 (1973-11-01), Smith
patent: 3825094 (1974-07-01), Burdick
patent: 3831708 (1974-08-01), Terry
patent: 3891048 (1975-06-01), Burdick
patent: 3995876 (1976-12-01), Ronne
patent: 5139102 (1992-08-01), Pocapalia
Air Caster Corp., Brochure 106L, no date.
Banner Donald W.
Johnson Brian L.
Luby Matthew
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