Road structure – process – or apparatus – Apparatus – Rotating drum – roller or tire
Reexamination Certificate
2001-10-09
2003-07-01
Hartmann, Gary S. (Department: 3673)
Road structure, process, or apparatus
Apparatus
Rotating drum, roller or tire
C404S132000, C180S019100
Reexamination Certificate
active
06585451
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to lawn and landscaping equipment, and is more particularly directed to self-powered equipment for rolling or compacting soil. The invention is specifically directed to a walk-behind lawn roller that permits an operator to control the direction and speed of travel with great precision, and without risk of damage to existing lawn, pavement or soil.
There now exists a need for a convenient method for rolling down topsoil in preparation for laying down of a new lawn. A need exists for rolling flat existing lawns, as well. At the present time what exists for this purpose is a lawn roller that has to be pulled or dragged by hand, or a roller that has to be towed behind a tractor. Both of these techniques are slow and awkward, and are somewhat unworkable if the terrain is anything but flat. What is needed is a lawn roller that is easy to turn and move about on a yard or lawn, without having to be pushed, pulled, or towed. In order to work the soil in areas near trees, buildings, or other structures, the lawn roller should be turnable in a small a radius as possible, but without noticeable damage to the lawn. In addition, to increase the mobility of the unit between work sites, and to adjust the weight of the unit to a given application, a means of removable weighting or ballasting should be used, and the use of water filled drums should be avoided.
Some lawn and construction equipment now exists for rolling earth or topsoil, but these are not entirely suited for the purposes served by this invention. An example of an existing self-propelled lawn roller is described in Cross U.S. Pat. No. 4,208,151. In that example, there is only a single drum roller. There is no means for turning the roller or changing direction, except brute force applied to the handle bar. This construction limits the total width of the roller. Another walk-behind soil compactor is described in Artzberger U.S. Pat. No. 4,732,507, which employs a pair of drums journalled side by side on a drum frame. These drums are driven by a common gear drive, and thus both drums turns together.
Hydraulic drive mechanisms have recently been employed in walk-behind self-propelled lawn mowers, one example of which is described in Zvolanek U.S. Pat. No. 5,518,079. In these lawn mowers, there is a separate hydraulic drive motor associated with the drive wheel on each side of the mower, and the operator can control the speed and direction of travel by squeezing control levers on the handle. However, despite the longstanding need for an improved lawn roller, no one has yet been motivated to incorporate the drive mechanism of this type of lawn mower into a split drum lawn roller.
OBJECTS AND SUMMARY OF THE INVENTION
Accordingly, it is an object of the invention to provide an effective and efficient technique for rolling and flattening soil in preparation for laying a lawn, or for rolling and flattening an existing lawn.
It is another object to provide a an improved self-propelled lawn roller for lawn installation and maintenance, which may be employed at golf courses, athletic fields, or parks, and which may be used in lawn care for commercial and residential applications.
It is a further object to provide a lawn roller that may be of increased width, and which may be used without difficulty and without a need to pull, push or tow it.
It is a still further object to provide a lawn roller that can be turned in a zero radius turn without damage to the lawn.
It is still another object to provide a lawn roller in which weight can be added or removed, and which avoids having to carry water within the roller drums.
According to an aspect of this invention, a power lawn roller has two roller drums that share a common axis and are individually movable. There is a frame that carries a transverse axle, and a left roller drum and a right roller drum are both journalled, side by side, on the axle. An engine is mounted on the frame and powers separate left and right independent hydraulic drive mechanisms providing motive power to the left and right roller drums, respectively. The hydraulic drive mechanism are each capable of rotating the associated drum at a forward speed and at a reverse speed, and at any desired speed in between, including idle. The control handle assembly for the unit has left and right control handles or squeeze handles, each operatively coupled to the associated drive mechanism, and this permits the operator to control the rotation speed of each of the drums. Directional control is entirely at the discretion of the operator. This arrangement allows the operator to move the lawn roller in a forward, reverse, left, or right direction, with the lawn roller responding immediately to the operator's hand actions on the squeeze levers. The drums can be rotated in different directions at the same time, allowing the operator to spin the lawn roller at its own center. There is a rear balance wheel or caster that also serves to press down the narrow strip of earth that is left by the gap between the two drums.
In a preferred mode, the hydraulic drive includes left and right hydraulic motors, and a continuous web drive between each hydraulic motor and the respective drum roller. The web drive may be a chain and sprocket drive, or may be a timing belt drive, for example.
Instead of using water to add weight to the drums, there are external weights, e.g., “suitcase” weights, mounted removably on racks to the left and right of the engine above the drums and somewhat forward of the drum axis. These weights can be removed when not needed, for example, when using the lawn roller on very loose soil, or when loading the unit onto a truck.
The principle of this invention can be employed in an extra-wide roller, for example, more than 48 inches across.
The propulsion system may be a gasoline engine, or may be any other available power source.
The above and many other objects, features, and advantages of this invention will become apparent to persons skilled in the art from the ensuing description of a preferred embodiment, which should be considered in connection with the accompanying Drawing.
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