US 12,226,351 B2
Hydraulic circuit for a patient handling apparatus
Ross T. Lucas, Paw Paw, MI (US); William Ross Heneveld, Jr., Kalamazoo, MI (US); Chad C. Souke, Vicksburg, MI (US); and Thomas A. Puvogel, Kalamazoo, MI (US)
Assigned to Stryker Corporation, Portage, MI (US)
Filed by Stryker Corporation, Kalamazoo, MI (US)
Filed on Dec. 20, 2023, as Appl. No. 18/390,552.
Application 18/390,552 is a continuation of application No. 17/081,608, filed on Oct. 27, 2020, granted, now 11,896,531.
Claims priority of provisional application 62/926,712, filed on Oct. 28, 2019.
Prior Publication US 2024/0115440 A1, Apr. 11, 2024
This patent is subject to a terminal disclaimer.
Int. Cl. F15B 1/02 (2006.01); A61G 1/02 (2006.01); A61G 1/056 (2006.01); F15B 11/042 (2006.01); F15B 13/044 (2006.01)
CPC A61G 1/0567 (2013.01) [A61G 1/0212 (2013.01); A61G 1/0262 (2013.01); F15B 1/024 (2013.01); F15B 11/0423 (2013.01); F15B 13/044 (2013.01); F15B 2211/45 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A patient handling apparatus comprising:
a patient support surface;
a base; and
a hydraulic circuit comprising:
a hydraulic cylinder operable to selectively move the patient support surface or the base relative to the other of the patient support surface or the base, the hydraulic cylinder having a rod, a cap end chamber, and a rod end chamber, the rod having an extension or retraction speed;
a pump; and
a fluid reservoir; and
the hydraulic circuit being operable to control the flow of hydraulic fluid between the hydraulic cylinder and the fluid reservoir, wherein the hydraulic circuit includes a bypass circuit configured to selectively open fluid communication between the hydraulic cylinder and the fluid reservoir to bypass the pump for faster evacuation of the hydraulic fluid from the hydraulic cylinder, wherein the hydraulic circuit includes an accumulator separate from and in fluid communication with the hydraulic cylinder and the fluid reservoir to maintain pressure of the hydraulic fluid in the hydraulic circuit,
wherein the accumulator maintains an inlet of the pump submerged in hydraulic fluid, and wherein the accumulator is pre-charged to pressurize hydraulic fluid in at least one of the accumulator and the reservoir.
 
16. A patient handling apparatus comprising:
a patient support surface;
a base; and
a hydraulic circuit including a pump, a fluid reservoir, and a hydraulic cylinder operable to selectively move the patient support surface or the base relative to the other of the patient support surface or the base, and the hydraulic circuit being operable to control the flow of hydraulic fluid between the hydraulic cylinder and the fluid reservoir, wherein the hydraulic circuit includes an accumulator separate from and in fluid communication with the hydraulic cylinder and the fluid reservoir to maintain pressure of the hydraulic fluid in the hydraulic circuit,
wherein the accumulator maintains an inlet of the pump submerged in hydraulic fluid, and wherein the accumulator is pre-charged to pressurize hydraulic fluid in at least one of the accumulator and the reservoir.