Excavating – Ditcher – Condition responsive
Reexamination Certificate
2003-01-14
2004-07-06
Pezzuto, Robert E. (Department: 3671)
Excavating
Ditcher
Condition responsive
C037S904000, C701S050000
Reexamination Certificate
active
06757992
ABSTRACT:
FIELD OF THE INVENTION
The present invention pertains generally to a work vehicle that has a bucket, such as a skid steer loader, and, more particularly to a work vehicle with a bucket shaker to dislodge material from the bucket, if necessary. More particularly, the present invention relates to an improved work vehicle that includes a mechanism for dislodging material from the bucket that provides automatic bucket shaking under the control of an on board computer or microprocessor.
BACKGROUND OF THE INVENTION
Skid steer loaders (also known as “skidders”) are work vehicles that include four wheels rotatably mounted to a frame, an engine mounted on the frame and connected by a transmission to rotate at least two wheels, a cab compartment mounted on the frame that includes a seat for an operator, manual controls and a display panel disposed in the cab compartment, a boom assembly rotatably mounted on the frame and connected to a pair of hydraulic boom cylinders for moving the boom assembly, and an implement assembly connected to the boom assembly. Typically, one or more hydraulic cylinders are used to manipulate the implement assembly. Preferably, the implement assembly is a bucket assembly, wherein the implement is a bucket and a pair of hydraulic bucket cylinders is used to move the bucket assembly. Other types of work vehicles that are similar to skid steer loaders include tractors and bulldozers.
When a skidder is equipped with a loader bucket, the work vehicle is primarily used for digging. One issue that arises during digging operations is that dumping of dirt and other potentially sticky materials such as manure, fertilizers, sand, and the like, from the loader bucket may be incomplete, leaving behind a residue. Consequently, some materials can remain stuck to the inside of the loader bucket. Typically, the operator of the skidder will manipulate the manual controls in the cab compartment to “shake” the loader bucket to assist any material residue to jar loose and fall out of the bucket. This operation entails rapidly moving the manual controls in a reciprocating manner to effect shaking of the bucket. Several problems emerge when shaking is attempted in the above manner. First, the amount of shaking the operator can achieve is limited to the human ability to reciprocate the manual controls to effect a shake. This means that the reciprocating movements have a relatively low frequency and generally a large magnitude so that the shake is suboptimal and it may take some amount of shaking to dislodge sticky material from the loader bucket. Second, the hydraulic circuit of the work vehicle generally includes a valve stack for activating movement of the boom assembly and loader bucket; however, the various solenoid activated spool valves used are relatively sluggish because they respond to analog signals, thereby placing a limitation on the capacity of the hydraulic circuit to shake the boom assembly and loader bucket. Third, such rapid manipulation of the manual controls may overstress the manual controls and render them prone to damage.
To operate the hydraulic boom cylinders and the hydraulic bucket cylinders, an operator in the cab manipulates either hand or foot controls. The skid steer loader, or similar work vehicle, includes an electronic control circuit system that includes an onboard computer, microprocessor, or controller. For the purposes of this disclosure, a computer, microprocessor, or controller are considered to be equivalent and interchangeable elements. The onboard computer operates solenoids of electrohydraulic valves that activate the hydraulic boom and the hydraulic bucket cylinders.
U.S. patent application Publication US 2001/0007087 A1 to Brandt et al., which is incorporated herein by reference for all that it discloses, teaches a computer based control system for a skid steer loader that includes a computer receiving inputs from a control panel, various sensors, hand grip and foot pedal inputs, and a seat bar sensor. The computer generates outputs to hydraulic actuators and associated valves, and to electromechanical devices.
An object of the present invention is to provide an improved electronic control system for a work vehicle, or like machine, having a boom assembly and a loader bucket implement assembly connected to the boom assembly so that the improved electronic control system of the present invention maintains the benefits of the prior art electronic control systems while overcoming at least some of the drawbacks of these prior art control systems.
SUMMARY OF THE INVENTION
In accordance with the above objectives, the present invention provides, in a first embodiment, a work vehicle having an implement with: (a) a frame; (b) a boom arm assembly connected at one end to the frame; (c) an implement assembly pivotally connected to another end of the boom arm assembly and including the implement; (d) a first hydraulic implement cylinder connected to the implement assembly and positioned to pivotally rotate the implement relative to the boom arm assembly when a piston of the first implement cylinder is extended or retracted, the first hydraulic implement cylinder being connected to a first electrohydraulic valve for activating extension and retraction of the piston of the first implement cylinder; and (e) a controller connected to send control signals to activate the first electrohydraulic valve, wherein the controller sends a series of shaking control signals to alternately extend and retract the first implement cylinder to effect a shaking movement of the implement.
In accordance with a second embodiment of the invention, the first embodiment is modified so that the controller operates in a first operational mode and in a second operational mode, wherein the controller generates and sends a first series of control signals to the first electrohydraulic valve when operating in the first operational mode and the controller generates and sends the series of shaking control signals when operating in the second operational mode.
In accordance with a third embodiment of the invention, the second embodiment is modified to include a shaking mode activation switch connected to send a command signal to the controller, wherein when the activation switch is engaged the activation switch sends the command signal to the controller and the controller operates in the second mode so long as the controller receives the command signal from the activation switch.
In accordance with a fourth embodiment of the invention, the first embodiment is modified so that the first electrohydraulic valve is a cartridge valve having at least one digital coil, and the at least one digital coil is connected to receive control signals from the controller.
In accordance with a fifth embodiment of the invention, the first embodiment is modified to include a second hydraulic implement cylinder connected to the implement assembly and positioned to pivotally rotate the implement relative to the boom arm assembly when a piston of the second implement cylinder is extended or retracted, the second hydraulic implement cylinder being connected to the first electrohydraulic valve for activating extension and retraction of the piston of the second implement cylinder and the piston of the first implement cylinder, wherein the controller sends a series of shaking control signals to alternately extend and retract the first implement cylinder and the second implement cylinder to effect a shaking movement of the implement.
In accordance with a sixth embodiment of the invention, the first embodiment is modified to include a second hydraulic boom cylinder connected to the boom arm assembly and positioned to move the boom arm assembly relative to the frame of the work vehicle when a piston of the second boom cylinder is extended or retracted, the second hydraulic boom cylinder being connected to a second electrohydraulic valve for activating extension and retraction of the piston of the second boom cylinder, and the controller is connected to send control signals to activate the second electrohydraulic val
Berger John G.
Haupt John R.
New Holland North America Inc.
Pezzuto Robert E.
Stader John William
Webb Collin A.
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