Abstract: Presented herein are systems and methods for attenuating certain pulsations in a hydraulic system comprising a pump and a hydraulic actuator. In certain aspects, an accumulator comprising an internal volume that is divided into a working chamber and a contained chamber may be utilized to at least partially attenuate propagation of certain pulsations in the system. The working chamber may be fluidically coupled to the pump via a first flow path and fluidically coupled to a chamber of the actuator via a second flow path. The system may be designed such that a first inertance of the first flow path is greater than a second inertance of the second flow path. Additionally or alternatively, the system may be designed such that a resonance associated with the first inertance and a compliance of the accumulator may occur at a resonance frequency of less than 90 Hz.

Abstract: A hydraulic sequencing valve is disclosed. A hollow spool is slidably carried in a valve body for motion between a first position in which fluid is caused to flow out a valve first port and a second position in which fluid is caused to flow into the first port. An annular partition is provided within the spool hollow, which divides the spool hollow into two chambers. When a pressure rise is experienced within the spool, a pre-set valve element trips, reducing pressure within one spool chamber. This pressure change shifts the spool to a second position. A check valve is provided in a separate valve body conduit. This check valve operates to assure that the valve spool remains in its second position until the valve and associated hydraulic system have completed the full cycle of operation.