US 12,084,134 B2
Controlled cylinder retraction with a closed hydraulic system
Evan Thomas Smith, Spirit Lake, IA (US); Derek D. Hruska, Lime Springs, IA (US); and Alan D. Gustafson, Lakefield, MN (US)
Assigned to AGCO Corporation, Duluth, GA (US)
Appl. No. 17/312,520
Filed by AGCO Corporation, Duluth, GA (US)
PCT Filed Oct. 29, 2019, PCT No. PCT/IB2019/059257
§ 371(c)(1), (2) Date Jun. 10, 2021,
PCT Pub. No. WO2020/121080, PCT Pub. Date Jun. 18, 2020.
Claims priority of provisional application 62/779,007, filed on Dec. 13, 2018.
Prior Publication US 2022/0049726 A1, Feb. 17, 2022
Int. Cl. B62D 55/30 (2006.01); F15B 1/04 (2006.01); F15B 15/14 (2006.01)
CPC B62D 55/305 (2013.01) [B62D 55/30 (2013.01); F15B 1/04 (2013.01); F15B 15/1423 (2013.01)] 20 Claims
OG exemplary drawing
 
1. An apparatus, comprising:
an accumulator; and
a cylinder fluidly coupled to the accumulator, the cylinder comprising:
a first portion comprising a first port, a second port, and a pressure relief valve, the pressure relief valve configured to regulate fluid flow from the second port to the accumulator;
a ram in slidable relation to the first portion, the ram comprising an internal recess and a predefined stroke length;
a spring disposed in the internal recess; and
a rod moveable by the spring relative to the first port while permitting fluid flow, wherein the cylinder is configured to increase resistance to retraction of the ram by re-routing fluid flow to the accumulator through the pressure relief valve after the rod has reached a defined retraction distance.