US 12,065,346 B2
Clamp force control system for lift truck attachment with secondary hydraulic force control circuit
Christopher M. Walthers, Gresham, OR (US)
Assigned to Cascade Corporation, Fairview, OR (US)
Filed by Cascade Corporation, Fairview, OR (US)
Filed on Sep. 3, 2021, as Appl. No. 17/466,951.
Application 17/466,951 is a continuation of application No. 15/367,002, filed on Dec. 1, 2016, granted, now 11,136,229.
Prior Publication US 2021/0395061 A1, Dec. 23, 2021
This patent is subject to a terminal disclaimer.
Int. Cl. B66F 9/18 (2006.01); B66F 9/22 (2006.01); F15B 3/00 (2006.01); F15B 11/028 (2006.01); F15B 11/032 (2006.01); F15B 11/16 (2006.01)
CPC B66F 9/183 (2013.01) [B66F 9/22 (2013.01); F15B 3/00 (2013.01); F15B 11/028 (2013.01); F15B 11/032 (2013.01); F15B 11/161 (2013.01); F15B 2211/6303 (2013.01); F15B 2211/7107 (2013.01); F15B 2211/76 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A hydraulic control circuit for limiting clamp pressure applied by opposed clamp arms against a load, the clamp arms moveable towards and away from each other by at least one positioning unit, the clamp arms each fitted with at least one bladder holding fluid, the hydraulic control circuit comprising:
(a) a charging system different from said at least one positioning unit, the charging system activated by movement of the clamp arms toward each other, and operated by pressurizing the fluid to expand the at least one bladder; where
(b) the charging system expands the at least one bladder independently of movement of the clamp arms by the at least one positioning unit.