Delay valve for a hydraulic work support

A delay valve configured for delaying release of hydraulic pressure in a hydraulic holding device, the delay valve comprising:

• a housing forming an inlet port, an outlet port, and a piston chamber, wherein the inlet port is selectively fluidly coupled with the piston chamber, and the inlet port is selectively fluidly coupled with the outlet port;
• a check valve located between the inlet port and the outlet port, wherein the check valve is actuatable between an open configuration allowing fluid to flow therethrough and a closed configuration blocking fluid from flowing therethrough;
• a piston translatable within the piston chamber, the piston having a rod portion translatable toward and away from the check valve, wherein the rod portion is configured to hold the check valve in the open configuration when the piston is in a first stroke position and to release the check valve to the closed configuration when the piston is in a second stroke position, wherein the piston translates from the first stroke position to the second stroke position via hydraulic pressure when hydraulic fluid flows from the first inlet port to the piston chamber, thereby pressing the piston to translate in a direction away from the check valve;
• and
• a flow control device provided between the inlet port and the piston chamber, the flow control device having an outer surface, a flow control passageway with an inner surface, and a flow control valve, wherein the flow control valve is configured to actuate between a naturally closed state in which fluid is blocked from passing through the flow control passageway and an open state achieved by force of hydraulic fluid flowing in through the inlet port, wherein a gap or orifice is provided between the outer surface of the flow control device and the housing, wherein a size of the gap or orifice is adjustable and controls how quickly fluid flows out from the piston chamber to the inlet port while the flow control valve is in a closed state and the hydraulic fluid is flowing out of the inlet port, thus controlling an amount of delay between a release of hydraulic fluid outward through the inlet port and a release of hydraulic fluid from within the piston chamber, wherein the release of hydraulic fluid from within the piston chamber causes the piston to return to the first stroke position and thus actuate the check valve into the open configuration after the amount of delay.

A method of providing instantaneous hydraulic flow in a first flow direction to a hydraulic holding device and delayed hydraulic flow in a second flow direction from the hydraulic holding device, the method comprising the steps of:

• receiving with an inlet port a flow of hydraulic fluid flowing in the first flow direction toward and through an outlet port to the hydraulic holding device;
• holding open a check valve between the inlet port and the outlet port with a rod portion of a piston, wherein the piston is translatable within a piston chamber;
• hydraulically opening a flow control valve located between the inlet port and the piston chamber, such that hydraulic fluid continues to flow in the first flow direction and into the piston chamber;
• hydraulically translating the piston in the piston chamber in a direction away from the check valve via the hydraulic fluid in the piston chamber, such that the rod portion disengages from the check valve;
• closing the check valve such that the hydraulic fluid stops flowing between the inlet port and the outlet port;
• closing the flow control valve such that hydraulic fluid stops flowing between the inlet port and the piston chamber therethrough;
• releasing hydraulic fluid through the inlet port in the second flow direction;
• releasing hydraulic fluid from the piston chamber into the inlet port in the second flow direction through at least one orifice that fluidly couples the piston chamber and the inlet port even while the flow control valve remains closed;
• hydraulically translating the piston in the piston chamber in a direction toward the check valve via the release of the hydraulic fluid from the piston chamber, such that the rod portion engages the check valve after a delay time proportional to at least one of the size of the at least one orifice, a stroke length of the piston, and a viscosity of the hydraulic fluid;
• and
• opening the check valve via mechanical force by the rod portion of the piston after the delay time, thereby releasing hydraulic fluid from the outlet port and the hydraulic holding device in the second flow direction toward the inlet port.