US Patent No. 10,987,260

PATIENT HANDLING APPARATUS WITH HYDRAULIC CONTROL SYSTEM


Patent No. 10,987,260
Issue Date April 27, 2021
Title Patient Handling Apparatus With Hydraulic Control System
Inventorship Chad Conway Souke, Portage, MI (US)
Ross Timothy Lucas, Paw Paw, MI (US)
Assignee Stryker Corporation, Kalamazoo, MI (US)

Claim of US Patent No. 10,987,260

1. A patient handling apparatus comprising:a frame;
a base;
a lift assembly supporting said frame relative to said base, said lift assembly configured to extend or contract to raise or lower said base or said frame with respect to the other of said base and said frame; and
a control system comprising:
at least one hydraulic cylinder to extend or contract said lift assembly, said hydraulic cylinder having a rod, a cap end chamber, and a rod end chamber, and said rod having an extension speed;
a hydraulic circuit to direct the flow of hydraulic fluid to and from said hydraulic cylinder, said hydraulic circuit including a cap side hydraulic conduit, a rod side hydraulic conduit, and a pump, said cap side hydraulic conduit in fluid communication with said pump, and said rod side hydraulic conduit in fluid communication with said pump, and said pump configured to pump fluid to and from said cap end chamber of said cylinder through said cap side hydraulic conduit and to pump fluid to and from said rod end chamber of said cylinder through said rod side hydraulic conduit, and said hydraulic circuit further including a third conduit in fluid communication with said rod side hydraulic conduit and said cap side hydraulic conduit allowing fluid communication between said rod end chamber and said cap end chamber without the fluid passing through said pump; and
a controller operable to control said pump and said hydraulic circuit, and based on an input signal indicative of a status or condition of the patient handling apparatus, when said rod is extending said controller configured to open fluid communication between said rod end chamber and said cap end chamber through said third conduit to redirect a portion of the fluid output from said rod end chamber to said cap end chamber by by-passing the pump to thereby increase said extension speed of said rod.