Guayule is a desert shrub indigenous to the southwestern United States and northern Mexico. Guayule is a source of natural rubber latex, which is found primarily in the bark or the branches, trunk and root system of the shrub. Processing to extract latex involves grinding the entire plant in a batch process that gently breaks open the cells of the plant, releasing intact rubber particles and creating an aqueous solution. The solution may be centrifuged to separate the latex from the remaining solution.
The guayule shrub is optimal for harvesting and processing at two years of growth, by which time it stands about 90 cm (3′) high and has a roughly spherical branch structure about 75 cm (30″) in diameter, growing out of a stalk or stalks from 0.6 to 5 cm (¼″ to 2″) in diameter. The entire shrub is harvested, cutting the stalk about 7.5 cm (3″) above the ground. The shrubs are transported to the processing plant, where they must be processed within about 72 hours or latex content is substantially degraded.
Traditional guayule harvesting is by hand, using a tool to cut through the tough trunk. The present invention is a mechanical harvester that cuts the bush and conveys it to a large trailer, from which the bushes can be baled and then transported to the processor.
The harvester of the present invention is a powered cutting and conveying device suitable for harvesting the guayule or any other small shrubs. Guides lift the shrub and expose the trunk to a pair of cutting blades at the same time that opposed pick-up belts engage the shrub branches and impel the shrub to an elevator conveyor belt. The elevator belt carries the now-severed shrub to the height of the entrance to a transport trailer, and then drops it. In the embodiment illustrated, the harvester is pulled behind a farm tractor and powered by the tractor's hydraulic system. An extendable lateral conveyor at the end of the main conveyor allows the harvested shrub to be dropped into a carrier pulled alongside the harvester.
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As better seen in
In one embodiment, blades (31) are 58 cm (23″) diameter carbon-tipped steel sawmill blades rotating at about 2000 to 2200 rpm. The blades slightly overlap and rotate in opposite directions, so that each one is moving front-to-back at the area of overlap. In this embodiment, the blades are individually powered by 7 hp hydraulic motors (33), connected by individual blade shafts (32). The motors are run off the main hydraulic line from the tractor.
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As noted, the rear of the belt pair assembly extends above the conveyer belt, so harvested shrubs are dropped onto the conveyor belt. The pick-up belts are powered by separate hydraulic motors connected to the tractor's auxiliary hydraulic pumps.
One embodiment of the invention is configured to harvest two rows of shrubs, normally planted 1 m (40″) apart between furrows. Two sets of separators (21) run along an adjacent pair of crop rows. As the shrubs are lifted by the separators, the trunks encounter the counter-rotating cutting blades (31) at the same time that the branches are engaged by the open ends of the pick-up belts (41). The trunks are severed and the harvested shrubs are carried back to the conveyor belt.
Conveyor belt (5) is of standard design, except that a plurality of shrub engagers (61) are mounted throughout the length of the belt to keep shrubs from slipping along the belt. In one embodiment, the shrub engagers are 7.5 cm (3″) flat-head bolts passed through the belt and secured with a washer and locknut.
The conveyor belt assembly can be raised to a height of a 3.6 m (12′) crop carrier vehicle, as in
In the embodiment illustrated here, the entire harvesting unit is operated in a conventional manner by a plurality of hydraulic motors powered by the tractor's main and auxiliary hydraulic supply lines. A feed from the main tractor pump enters a sequence of hydraulic flow separators, resulting in four uniform pressure flow lines, each of which feeds a blade motor connected by a shaft to a blade directly below the motor. Recirculating hydraulic fluid is sent to a 150 l (40-gallon) reservoir tank mounted in the base of the trailer and then returned to the flow circuit.
Additional hydraulic motors are run from the tractor's auxiliary hydraulic supply. One motor turns each of the four pick-up belts. Another motor turns the conveyor belt. Another turns the lateral conveyor. A motor lifts and lowers the conveyor ramp, and a pair of motors raises and lowers the lateral conveyor and extends and retracts it. All the associated hydraulic lines use the same reservoir.
While the invention has been described with reference to particular embodiments thereof, persons of ordinary skill in the art will readily apprehend additional configurations of the harvester that are within the scope of this invention. By way of example only, the device could be widened to harvest more than two rows at a time or configured for a single row. The harvesting mechanism may be integrated into a self-propelled vehicle or use other power means to run the various motors.
This application claims the benefit of priority of U.S. Provisional Application Ser. No. 60/897,087, filed Jan. 22, 2007.
Number | Date | Country | |
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60897087 | Jan 2007 | US |