| 摘要 |
A dual hydraulic oscillator for the reciprocating cutter of an agricultural machine is provided. The dual oscillator has two pistons reciprocating in opposite directions and a single pilot valve, with resynchronization performed twice per cycle of the oscillator. Also provided is a single or dual hydraulic oscillator comprising a cylinder having first and second opposed ends. A reversing pilot valve is provided for controlling flow of pressurized fluid to at least one of the first and second cylinder ends. The pilot valve includes first and second pilot passages for controlling the reversing operation of the pilot valve. A piston reciprocates between first and second positions in the cylinder. The piston has an inner bore. The bore has first and second circumferential logic grooves. An inner logic mechanism is slidably received in the bore. The inner logic mechanism has a first coupling mechanism for fluidly coupling the logic grooves to the pressurized fluid and a second coupling mechanism for fluidly coupling the logic grooves to the first and second pilot passages. The first coupling mechanism is fluidly coupled to the second coupling mechanism by the first logic groove, and the second coupling mechanism is fluidly coupled to the first pilot passage, exclusively when the piston is in the first position. The first coupling mechanism is fluidly coupled to the second coupling mechanism by the second logic groove, and the second coupling mechanism is coupled to the second pilot passage, exclusively when the piston is in the second position, thereby to alternately reverse the pilot valve to change the fluid flow to at least one of the first and second cylinder ends for producing the reciprocation of the piston.
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