US 12,310,896 B2
Hydraulic valve and system
Chad C. Souke, Vicksburg, MI (US); and Ross T. Lucas, Paw Paw, MI (US)
Assigned to Stryker Corporation, Portage, MI (US)
Filed by Stryker Corporation, Kalamazoo, MI (US)
Filed on Nov. 22, 2023, as Appl. No. 18/517,446.
Application 18/517,446 is a continuation of application No. 18/097,777, filed on Jan. 17, 2023, granted, now 11,865,051.
Application 18/097,777 is a continuation of application No. 17/081,593, filed on Oct. 27, 2020, granted, now 11,583,455, issued on Feb. 21, 2023.
Claims priority of provisional application 62/926,711, filed on Oct. 28, 2019.
Prior Publication US 2024/0082079 A1, Mar. 14, 2024
This patent is subject to a terminal disclaimer.
Int. Cl. A61G 1/056 (2006.01); A61G 1/02 (2006.01); F15B 11/042 (2006.01); F15B 11/044 (2006.01); F15B 13/042 (2006.01); F15B 13/01 (2006.01)
CPC A61G 1/0567 (2013.01) [A61G 1/0212 (2013.01); A61G 1/0262 (2013.01); F15B 11/044 (2013.01); F15B 13/042 (2013.01); F15B 11/0423 (2013.01); F15B 13/015 (2013.01); F15B 2211/45 (2013.01)] 23 Claims
OG exemplary drawing
 
1. An apparatus comprising:
a hydraulic circuit, said hydraulic circuit having a first conduit, a second conduit, a third conduit, and a valve assembly; and
said hydraulic circuit configured to control said valve assembly to affect fluid communication with said third conduit of said hydraulic circuit based on a flow of hydraulic fluid in said first conduit with respect to a pump, said valve assembly including a pilot piston moveable within said valve assembly, wherein a differential flow developed from said pump is applied to said pilot piston such that an increase or decrease in said differential flow biases said pilot piston to move within said valve assembly, and wherein said pilot piston is operable to affect said fluid communication with said third conduit in response to a threshold level of differential flow with respect to said pump.
 
9. A pilot operated control valve assembly comprising:
a first chamber with a first inlet for fluid communication with a first conduit, a second inlet, an outlet for fluid communication with a second conduit, and a pilot piston assembly mounted for movement in said first chamber;
a second chamber having an inlet for communication with a third conduit, an outlet, and a valve poppet movably mounted in said second chamber between a closed position and one or more open positions;
said pilot piston assembly includes a pilot piston with a piston side facing said first inlet of said first chamber and a pilot rod, said pilot rod extending from said first chamber into said second chamber to selectively move said valve poppet, said second chamber being sealed from said first chamber; and
said second inlet of said first chamber is in fluid communication with said outlet of said first chamber so that fluid flows to said outlet of said first chamber from said first inlet or said second inlet to allow fluid flow between said first conduit and said second conduit during operational fluid flow conditions.
 
17. A patient handling apparatus comprising:
a hydraulic circuit and a hydraulic cylinder to raise or lower a component of the patient handling apparatus;
a pump;
a reservoir;
said hydraulic cylinder having a rod, a cap end chamber, and a rod end chamber, said hydraulic circuit having a control valve assembly operable to direct the flow of hydraulic fluid between said pump, said hydraulic cylinder, and said reservoir; and
said control valve assembly configured to affect fluid communication between a first chamber of said hydraulic cylinder and said reservoir based on a flow condition of the hydraulic fluid flowing to a second chamber of said hydraulic cylinder, said control valve assembly including a pilot piston moveable within said valve assembly, wherein a differential flow developed from said pump is applied to said pilot piston such that an increase or decrease in said differential flow biases said pilot position to move within said valve assembly, wherein said pilot piston is operable to affect said fluid communication with said third conduit in response to a threshold level of said differential flow with respect to said pump.