Air-hydraulic pump with auxiliary pumping means

A pressurized air hydraulic fluid pump for use in a hydraulic system, comprising:

• a pump body;
• air supply means for providing pressurized air to said pump body;
• air operated control means associated with said pump body and operable by pressurized air provided to said pump body;
• first pumping means responsive to said control means for delivering a first level of hydraulic pressure to said system at a first flow rate, comprising a reciprocating piston including a rod and a head having a pair of faces, and wherein pressurized air through said air operated control means causes reciprocating movement of said piston head resulting in reciprocating movement of the end of said rod, which acts on hydraulic fluid to deliver said first level of hydraulic pressure at said first flow rate;
• and
• auxiliary pumping means responsive to said control means for delivering hydraulic pressure to said system at a second level less than said first level and at a second flow rate greater than said first flow rate, said auxiliary pumping means being responsive to the load on said system such that, when the load on said system exceeds a predetermined level, said auxiliary pumping means ceases operation and said first pumping means supplies pressure to said system, wherein said auxiliary pumping means comprises a floating ring slidably mounted to said piston rod, said ring including a hydraulic fluid contact surface greater than that provided by the end of said piston rod and a surface exposed to pressurized air through said air operated control means.

An apparatus for selectively providing hydraulic fluid pressure in a hydraulic system in response to a supply of air pressure, comprising:

• an air intake block for receiving a supply of pressurized air;
• a control block spaced from said air intake block;
• a hydraulic block spaced from said control block;
• means defining a first cavity in the space between said intake block and said control block;
• means defining a second cavity in the space between said control block and said hydraulic block;
• means for communicating pressurized air from said intake block to said control block;
• control means disposed within said control block operable by pressurized air communicated to said control block;
• actuator means for selectively providing pressurized air to said control block;
• a first member mounted for reciprocating movement within said first cavity in response to pressurized air supplied through said control means;
• hydraulic fluid supply means for providing hydraulic fluid to said second cavity;
• primary pumping means disposed within said second cavity and responsive to reciprocating movement of said first member for delivering a first level of fluid pressure to said system at a first flow rate;
• and
• load sensitive auxiliary pumping means disposed within said second cavity for delivering a second level of fluid pressure to said system less than said first level and at a flow rate greater than said first flow rate;
• wherein, through said control means, said pressurized air causes reciprocating movement of said first member within said first cavity resulting in pumping of fluid by both said primary and auxiliary pumping means up to a predetermined load on said system, whereafter said auxiliary pumping means ceases operation due to the load on said system and said primary pumping means supplies pressure to said system.