US 12,274,653 B2
Hydraulic drive unit for a stretcher and stretcher with a hydraulic drive unit
Christian Hart, Nittendorf (DE)
Assigned to HAWE HYDRAULIK SE, Aschheim (DE)
Filed by HAWE Hydraulik SE, Aschheim (DE)
Filed on Aug. 10, 2022, as Appl. No. 17/818,844.
Claims priority of application No. 102021209014.1 (DE), filed on Aug. 17, 2021.
Prior Publication US 2023/0233392 A1, Jul. 27, 2023
Int. Cl. A61G 7/10 (2006.01); A61G 1/013 (2006.01); A61G 1/04 (2006.01); A61G 1/056 (2006.01)
CPC A61G 7/1017 (2013.01) [A61G 1/0567 (2013.01); A61G 1/013 (2013.01); A61G 1/04 (2013.01); A61G 1/0565 (2013.01)] 8 Claims
OG exemplary drawing
 
1. A hydraulic drive unit for a stretcher, the drive unit comprising:
a hydraulic circuit with a differential cylinder, the differential cylinder having a rod working chamber and a piston working chamber;
a pump;
a tank;
a rigid hollow body, wherein the tank is disposed within the hollow body, and the hollow body has a relief to the environment; and
a valve assembly switchable into at least a first state and a second state, wherein the rod working chamber of the differential cylinder is connected to the tank in the first state and to the pump in the second state, and wherein the piston working chamber of the differential cylinder is connected to the pump in the first state and to the tank in the second state;
wherein the tank is an elastic tank separated from atmosphere with a variable tank volume so that the hydraulic circuit is configured as a closed hydraulic circuit.