Planting – Drilling – Having depositor feature
Reexamination Certificate
1999-04-29
2001-01-09
Batson, Victor (Department: 3671)
Planting
Drilling
Having depositor feature
C111S921000, C060S486000, C180S053610, C221S278000
Reexamination Certificate
active
06170412
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to improvements in hydraulic systems for agricultural implements and to control and drive systems for same.
The demand for fluid power from tractors is increasing with the size of implements and with the increased use of hydraulic power on implements. Farm practices are becoming increasingly large and in order to complete seeding and preparations, there are demands for larger air seeding implements. Larger air seeder implements require more hydraulic power for hydraulically driven fans, augers, and other accessories. This demand may be more than the tractor can supply or leaves no reserve capacity to operate implement folding or lifting operations. The hydraulic accessories on the implement may also be a significant distance from the tractor hydraulic power source leading to power losses in long fluid lines and connections.
Separate hydraulic power systems have been used such as ground driven pumps but these have had separate fluid reservoirs, filters, and coolers, making the systems expensive. The Force V air seeder manufactured first by Friggstad Manufacturing and later by Flexi-Coil used a ground driven hydraulic pump to provide fluid power to the air seeder fan. The pump drive was achieved through a planetary gear system. Two pumps driven separately by two ground wheels were used in order to provide enough fluid power to drive the fin motor. Requirements for a fluid reservoir, cooling, filtration and the planetary gear drive added to the expense of the system. Other air seeders have used belts and pulleys to directly drive the fan from the ground wheels.
In all of these prior systems the fan speed was directly dependent on the speed that the implement was towed across the ground Inaccurate metering, delivery, and line plugging were problems with these prior systems.
An improved system used PTO (power take-off) driven pumps to provide fluid power to make up the shortcomings of the tractor hydraulics. ASAE paper 921604 describes such a hydraulic system. However, this is shown to separately provide power to implement actuators and is not shown to be combined with the tractor fluid power, except that the tractor provides a charge pressure to prevent cavitation of the PTO driven pump. The pump is shown to be tied into tractor hydraulics to make combined use of tractor hydraulic filter, reservoir, and cooling systems, but the high pressure fluid power delivered from the PTO pump is not shown to be connected in parallel with the high pressure from the tractor pump to operate implements together. The PTO pump system is sometimes in a location far from where the fluid power is required on an air seeder. Increased line sizes are required to avoid power losses and more connections and setup are required in order to use these systems.
It would be desirable to provide a hydraulic system on the implement which provides the extra power required without giving the operator further work and worry of connecting and setting up systems so they operate satisfactorily without significant loss in performance due to changing ground speeds, and a system which does not duplicate components already available on the tractor, thereby maintaining cost within reason.
A Design News article (issue date: Feb. 20, 1992), titled “PTO Driven Pump Augments Tractor Hydraulics” shows an auxiliary pump driven from a PTO drive and operating an implement motor. This circuit shows the tractor provides a charge pressure to the auxiliary pump limited by a relief shown on the tractor return line. The pressure available to the motor is not the combination of the tractor with the auxiliary pump but only the difference between the pressure provided by the auxiliary pump and the charge pressure because the charge pressure is also seen by the return side of the implement motor.
SUMMARY OF THE INVENTION
In accordance with one aspect the invention provides a hydraulic drive system adapted to be connected to a primary or main source of hydraulic power including a main pump and a reservoir; said hydraulic drive system comprising:
a hydraulic motor for driving a load, a high pressure supply line connected to an inlet of said hydraulic motor and a low pressure return line connected to an outlet of said hydraulic motor, said supply and return lines adapted to be connected to output and return ports respectively of said main source, and a boost pump having an outlet and an inlet in communication with said supply and return lines respectively such that when said drive system is connected to said main source said boost pump is in parallel with said main pump, and a drive for said boost pump whereby in use the output of said boost pump complements the output of the main pump to assist in delivering fluid to said hydraulic motor sufficient as to help in maintaining a desired speed thereof.
The present invention thus includes a hydraulic system that combines fluid power from an auxiliary source (including a boost pump) with a tractor hydraulic power source for increased power capacity. This novel system does so without additional filtering, cooling, or reservoir components by making use of the tractor components. There have been other auxiliary systems that make use of tractor hydraulic system components but these have not shown a combining of power sources to operate implements. Applicants' system also typically includes a flow control which the operator adjusts to control the boost flow portion being added to drive the fan and to control aircart fan speed.
The present invention thus provides, in one aspect, a parallel circuit arrangement having features not shown in the auxiliary rangement noted above. In applicants' circuit, the tractor maintains a base flow rate, even when the boost pump is not operating. Also, the boost pump circulates flow within a part of the circuit and all the flow to the motor does not circulate back to the tractor, reducing line size requirements and losses. The flow requirement is shared between the boost pump and the tractor.
Other features of this aspect of the invention include:
a means to couple two or more fluid power sources with controls to adjust the flow volume being delivered to the loads and/or control the proportion of volume from each source;
a means to couple two or more fluid sources to a load whereby at least one source maintains a minimum of volume to the load(s) for minimum operation;
a hydraulic circuit for combining fluid power from a ground driven pump with that from the tractor to power hydraulic circuits on an implement, particularly power for an air seeder fin.
In accordance with another aspect of the invention there is provided an agricultural machine having a hydraulic drive system adapted to be connected to a primary or main source of hydraulic power including a main pump and a reservoir, wherein said hydraulic drive system includes a hydraulic motor for driving a load, a high pressure supply line connected to an inlet of said hydraulic motor and a low pressure return line connected to an outlet of said hydraulic motor, said supply and return lines adapted to be connected to output and return ports respectively of said main source, a boost pump for complementing/supplementing the output of the main pump when in use and a drive for said boost pump including a ground engaging wheel connected via a mechanical drive train to said boost pump whereby said boost pump is driven at speeds dependent on the ground speed of the agricultural machine.
This aspect of the invention typically includes an improved pump drive including a ground drive mounting arrangement having a geometry which results in a self-engaging reaction between a drive sprocket and a drive chain which s operating wear and provides optimum life of the chain and sprocket drive components to drive the hydraulic boost pump. By properly selecting sprocket drive sizes, hydraulic pump size, drive speed, and flow control, the allowable system forces created enable the ground driven boost pump to provide high pressure hydraulic fluid which is combined with tractor hydraul
Bodie Cameron D.
Memory Russell J.
Batson Victor
Flexi-Coil Ltd.
Miller Larry W.
Stader J. William
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