Harvesters – Motorized harvester – With condition-responsive operation
Reexamination Certificate
2002-09-19
2004-12-21
Pezzuto, Robert E (Department: 3671)
Harvesters
Motorized harvester
With condition-responsive operation
Reexamination Certificate
active
06832466
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to the field of cutting and mulching equipment. More specifically, the present invention relates to improved operator safety in the use of rotary brush cutters and mulchers.
BACKGROUND OF THE INVENTION
Cutting and mulching equipment is often used to cut away and/or clear brush including tall grass, plants, weeds, shrubs, wood chips, branches and the like. A common method for clearing brush involves a rotary brush cutter. Such a cutter has a blade that rotates in a plane generally parallel to the ground such that it generally uniformly cuts the brush.
A brush cutter may be mounted on a tractor loader(Bobcat) or other such surface loading machinery or equipment. The brush cutter is mounted generally on the front of a machine or cab such that the brush cutter clears a path for the operator and equipment on which the brush cutter is mounted.
A brush cutter may pose a risk of injury to an operator. A common problem occurs where an object is thrown from the cutting area of the brush cutter. The object may be a twig, a rock, or any other object that may pose a risk to an operator. There is a potential that such an object could hit an operator and cause injury. This problem is more pronounced when the rear portion of the brush cutter is raised off the ground with respect to the front portion, the rear portion being the portion nearest the operator.
It is thus preferable that the brush cutter have a protective mechanism, such as an automatic shut-down mechanism, for when the brush cutter is raised to a dangerous height off of the ground.
One mechanism in the prior art involves a set of rollers positioned at a rear portion of a brush cutter. These rollers are heavy so that they maintain contact with the ground. If the brush cutter is raised to a predetermined height, the rollers will drop down with respect to the brush cutter housing and cause the automatic shut-off mechanism to be actuated. A problem with this apparatus is that the rollers may cause an unnecessary shut-off if the brush cutter travels over a hole or crevice area that causes the rollers to drop down to the predetermined shut-off distance.
A similar problem can occur when the brush cutter travels over a log. The rollers will drop down once they have rolled over the log, thus unnecessarily implementing operation of the shut-off mechanism.
Another problem with this mechanism is that it adds significant weight to the brush cutter, thus limiting the vast majority of cabs that can carry the weight of the shut-off mechanism.
Another mechanism in the prior art involves the use of an apparatus wherein a shut-off mechanism is initiated based on the difference between the height of the brush cutter with respect to the height of a cab. This apparatus includes a chain having a first end bolted to the brush cutter and a second end secured to a chassis of the cab, to thus limit the height to which the brush cutter can be lifted off of the ground with respect to the cab. A problem with this mechanism is that the brush cutter may be located over an inclined surface with respect to the cab, thus unnecessarily initiating the shut-off mechanism.
Another problem with these prior art mechanisms is that they lack shut-off devices that extend along the entire length of the side of the brush cutter to prevent debris from escaping through the sides of the brush cutter. Also, these mechanisms can become caught on the ground and other debris during operation, requiring the operator to shut down the machine and clean them off. Another problem with these mechanisms is that they are independent of the electrical mechanism, or motor, that runs the brush cutter. Thus, the safety mechanisms may be removed from the brush cutter without affecting operation. For example, the chain or rollers may be removed from the brush cutter and the brush cutter will still be able to operate, thus making the effectiveness of the safety mechanism moot.
The present invention provides for an improved brush cutter that addresses these shortcomings.
SUMMARY OF THE INVENTION
The present invention relates to improvements in safety features for a brush cutter. The invention includes a protection barrier on the sides of a brush cutter such that objects are prevented from being impelled from the brush cutter toward the operator as the brush cutter passes over the objects. The present invention further includes an emergency stop system, wherein the brush cutter is automatically shut off when the rear portion of the brush cutter is raised to a dangerous height off the ground.
The brush cutter has a back end that is mounted to a drive vehicle, a front end opposite the back end, and two sides. The protective barrier comprises a side panel positioned outwardly of the sides of the brush cutter so as to prevent objects over which the brush cutter passes from being impelled out the sides of the equipment. Each side panel has a front end in the direction of the front end of the brush cutter and a back end in the direction of the back end of the brush cutter. The side panel front end has a hole proximate a hub, and the side panel back end has a slot extending generally vertically or vertically but slightly arcuately. The front end of the brush cutter structure has a pivot shaft that extends through the hub of the side panel. The side panel is able to pivot about the pivot shaft such that the back end of the side panel can pivot upwardly or downwardly with respect to the pivot shaft. The back end of the brush cutter structure has a slot rider that extends through the slot in the side panel. Thus, the side panel may pivot upwardly until the bottom of the slot engages the rider, and the side panel may pivot downwardly until the top of the slot engages the rider.
In operation, if the rear portion of the brush cutter becomes elevated, the back end of the side panel will pivot downwardly relatively. The side panel then prevents objects from being impelled out the side of the brush cutter, wherein the bottom portion of the side panel extends below the bottom of the brush cutter structure. As the rear portion of the brush cutter is leveled, the back end of the side panel will pivot upwardly relatively.
The emergency stop feature is achieved by employment of a system that shuts off the brush cutter motor when the rear portion of the brush cutter structure is elevated beyond a predetermined height. A hydraulic switch is employed such that, when the rear portion of the brush cutter motor is elevated, the hydraulic switch is depressed causing the motor to shut off.
An embodiment of the emergency stop system comprises a hydraulic cylinder secured to the brush cutter structure. The cylinder has a piston end extending toward the back of the brush cutter. The piston end is secured to a pivoting elbow. The pivoting elbow has a first joint pivoting about the piston end, a second joint pivoting about a lower portion of the brush cutter structure, and a third joint pivoting about the side panel.
The arm has a first joint that is connected to the third joint of the elbow and is able to pivot at that joint. The arm has a second joint that is connected to a middle portion of the side plate.
The hydraulic piston acts to force the side plate downwardly. The downward force is supplied by the piston to the first joint of the elbow and interacts with the arm to force the side plate downwardly.
A shut-off valve is positioned adjacent the back of the elbow portion of the pivoting elbow. The shut-off valve has a shaft extending therefrom toward the side panel. A yoke extends from the shaft. A pin extending from the side panel is able to engage the yoke to initiate the shut-off valve by rotating the shaft. A pin is set at a predetermined position on the side panel such that the shut-off valve is actuated only when the side panel moves downwardly a predetermined distance with respect to the housing.
The shut off height and shut off time are adjustable. Adjusting the shut off time may be beneficial to allowing the operator to raise the rotary brush cutter off t
Freiberg Scott E.
Roy Roger E.
Cross Tech Manufacturing, Inc.
Nawrocki, Rooney & Sivertson P.A.
Pezzuto Robert E
LandOfFree
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