US 12,392,331 B2
Hydraulic pump with two-stage operation
Nathan Adam Hughes, Cottage Grove, WI (US); and Curtis L. Van Weelden, Waukesha, WI (US)
Assigned to Enerpac Tool Group Corp., Milwaukee, WI (US)
Filed by Enerpac Tool Group Corp., Milwaukee, WI (US)
Filed on Aug. 16, 2022, as Appl. No. 17/889,051.
Application 17/889,051 is a continuation of application No. 15/981,869, filed on May 16, 2018, granted, now 11,415,119.
Claims priority of provisional application 62/507,130, filed on May 16, 2017.
Prior Publication US 2023/0039274 A1, Feb. 9, 2023
Int. Cl. F04B 1/04 (2020.01); F04B 23/02 (2006.01); F04B 39/10 (2006.01); F04B 17/06 (2006.01)
CPC F04B 1/04 (2013.01) [F04B 39/10 (2013.01); F04B 17/06 (2013.01); F04B 23/025 (2013.01)] 16 Claims
OG exemplary drawing
 
1. A pump comprising:
a frame including a reservoir configured to store hydraulic fluid;
a motor assembly supported by the frame;
a pump assembly operably driven by the motor assembly, the pump assembly being in fluid communication with the reservoir and configured to dispense hydraulic fluid out of the frame, the pump assembly including a first piston and a second piston;
a hub having an outer surface defining a first passageway communicating with the first piston and a second passageway spaced from the first passageway and communicating with the second piston, the first passageway and the second passageway being in communication with a pump outlet; and
a first valve having a first position in which the first passageway and the second passageway each communicate with the pump outlet, and a second position in which the first passageway is prevented from communicating with the pump outlet while the second passageway is communicating with the pump outlet.