Double-acting tandem piston pump

Claim 2

A tandem pump which comprises a central body, a cylinder of selected diameter mounted on and extending axially from each side of said body, a piston head in each cylinder in sealed relation therewith, a piston rod slidably mounted in said body having its ends secured to the pistons in said cylinders, inlet ports at both ends of one cylinder, separate outlet ports at both ends of said one cylinder, valves in said inlet and outlet ports admitting fluid to the cylinder on the suction stroke of the piston and discharging said fluid on the opposite side of the piston, combination inlet and outlet ports on the opposite ends of the other cylinder, means for selectively introducing fluid under pressure into one of said combination ports to reciprocate the piston in the cylinder between the ports, a control rod means controlled from the piston rod for controlling the flow of the pressured fluid to and from the combination ports whereby reciprocation of the piston by the pressurized fluid will reciprocate the piston in said one cylinder to alternately surge fluid through one and then the other of said outlet ports, mechanical means holding said control rod in a retracted fixed position during one stroke of the piston between the combination ports, and fluid pressure actuated means holding the control rod in an extended fixed position during the opposite stroke of said piston.

Claim 3

The pump of claim 1 wherein said means reversing flow through the combination inlet and outlet ports includes a solenoid actuated pilot valve tripped at the ends of the stroke of the piston rod and a high pressure oil valve actuated by the solenoid valve for controlling flow to and from said combination ports.

Claim 4

A tandem piston pump effective to surge water through a hose and self-propelling nozzle on the leading end of the hose to cause the hose and nozzle to jump at periodic intervals which comprises a central body, first and second cylinders of selected diameters each secured to an opposite side of said central body and extending coaxially therefrom, end heads on the outer ends of said cylinders, a piston rod slidably mounted in the central body and extending into both cylinders, pistons slidably mounted in the cylinders secured on the ends of the piston rod, a water inlet port in said body communicating with the inner end of the first cylinder, a water inlet port in the end head of said first cylinder communicating with the outer end of said first cylinder, a water outlet port in said body communicating with the inner end of said first cylinder, a water outlet port in said end head of said first cylinder communicating with the outer end of said first cylinder, valves in each of said inlet ports opening on the suction stroke of the piston in said first cylinder, valves in said outlet ports opening on the pressure stroke of the piston in said first cylinder, a combination inlet and outlet port in said central body communicating with the inner end of said second cylinder, a combination inlet and outlet port in the end head on said second cylinder communicating with the outer end of said second cylinder, a pump delivering oil under pressure to and receiving oil from said combination ports, a control rod controlled by said piston rod reversing oil flow through said combination ports to opposite sides of the piston in said second cylinder for reciprocating the piston to drive the piston in said first cylinder for surging water alternately through said outlet ports, mechanical means holding said control rod in one fixed position during one stroke of the piston in the second cylinder, and oil pressure actuated means holding said control rod in a second fixed position during the opposite stroke of said piston in the second cylinder.

Claim 5

A tandem piston pump effective to surge water through a hose and self-propelling nozzle on the leading end of the hose to cause the hose and nozzle to jump at periodic intervals which comprises a central body, first and second cylinders of selected diameters each secured to an opposite side of said central body and extending coaxially therefrom, end heads on the outer ends of said cylinders, a piston rod slidably mounted in the central body and extending into both cylinders, pistons slidably mounted in the cylinders secured on the ends of the piston rod, a water inlet port in said body communicating with the inner end of the first cylinder, a water inlet port in the end head of said first cylinder communicating with the outer end of said first cylinder, a water outlet port in said body communicating with the inner end of said first cylinder, a water outlet port in said end head of said first cylinder communicating with the outer end of said first cylinder, valves in each of said inlet ports opening on the suction stroke of the piston in said first cylinder, valves in said outlet ports opening on the pressure stroke of the piston in said first cylinder, a combination inlet and outlet port in said central body communicating with the inner end of said second cylinder, a combination inlet and outlet port in the end head on said second cylinder communicating with the outer end of said second cylinder, a pump delivering oil under pressure to and receiving oil from said combination ports, a control rod controlled by said piston rod reversing oil flow through said combination ports to opposite sides of the piston in said second cylinder for reciprocating the piston to drive the piston in said first cylinder for surging water alternately through said outlet ports, mechanical means holding said control rod in one fixed position during one stroke of the piston in the second cylinder, and oil pressure actuated means holding said control rod in a second fixed position during the opposite stroke of said piston in the second cylinder.

Claim 6

The pump of claim 3 wherein the means for reversing flow through the combination ports includes an oil actuated spool control valve selectively venting oil to said combination ports and a solenoid actuated pilot valve tripped by the piston rod controlling The oil actuated spool valve.

Claim 7

A pump having a pair of opposed cylinders, a piston rod projecting into both cylinders, piston heads on the ends of said rod, means for introducing fluid under pressure alternately into the opposite ends of one cylinder for reciprocating the piston therein to drive the piston rod for reciprocating the piston in the other cylinder, said means including an axial recess extending inwardly from the end of the piston rod in the cylinder receiving the fluid under pressure, a cap on said recess, a control rod in said recess having a first head engaged by the piston rod at one end of its stroke and by the cap at the other end of its stroke, an end head on the cylinder receiving the fluid under pressure, a reduced diameter portion on said control rod sliding through said end head in sealed relation therewith, a second head on the reduced diameter control rod portion beyond the end head of the cylinder, a supplemental cylinder receiving said second end head in slidable relation, a groove in said second head, spring-pressed detents in said supplemental cylinder engaging in said groove to hold the control rod in retracted position, a switch engaged by the control rod in the extended position thereof, and said control rod being reciprocated at the ends of the stroke of the piston rod to trip said switch whereby the detents will hold the control rod in stationary position between the ends of the piston rod stroke.

Claim 8

A pump having a pair of opposed cylinders, a piston rod projecting into both cylinders, piston heads on the ends of said rod, means for introducing fluid under pressure alternately into the opposite ends of one cylinder for reciprocating the piston therein to drive the piston rod for reciprocating the piston in the other cylinder, said means including an axial recess extending inwardly from the end of the piston rod in the cylinder receiving the fluid under pressure, a cap on said recess, a control rod in said recess having a first head engaged by the piston rod at one end of its stroke and by the cap at the other end of its stroke, an end head on the cylinder receiving the fluid under pressure, a reduced diameter portion on said control rod sliding through said end head in sealed relation therewith, a second head on the reduced diameter control rod portion beyond the end head of the cylinder, a supplemental cylinder receiving said second end head in slidable relation, a groove in said second head, spring-pressed detents in said supplemental cylinder engaging in said groove to hold the control rod in retracted position, a switch engaged by the control rod in the extended position thereof, and said control rod being reciprocated at the ends of the stroke of the piston rod to trip said switch whereby the detents will hold the control rod in stationary position between the ends of the piston rod stroke.

Claim 9

The pump of claim 5 wherein the seal for the control rod in the cylinder end head has a fluid trapping recess and the control rod has a shoulder bottoming against fluid trapped in said recess to cushion the outward driving of the rod through the end head.

Claim 10

In combination with a cylinder having an end head on one end thereof, a body at the opposite end thereof, a piston rod slidable through said body, and a piston on the piston rod in said cylinder, the improvement of a control device for regulating flow of oil under pressure into opposite ends of the cylinder for reciprocating the piston which comprises said piston rod having an axial recess communicating with the end head end of the cylinder, a control rod having one end freely movable in said recess and the other end slidable through said end head in sealed relation therewith, said control rod having opposed shoulders respectively outside of said end head and inside of said end head limiting sliding movement of the control rod through the end head, said control rod being pushed by fluid under pressure in the end head end of the cylinder to an extended position, means on the piston rod pulling the control rod to a retracted position, means on the end head holding the control rod in said retracted position whereby the rod is locked in fixed position except at the very ends of the stroke of the piston, and switch means tripped by the end of the control rod each time it is shifted by the piston rod.

Claim 11

In combination with a cylinder having an end head on one end thereof, a body at the opposite end thereof, a piston rod slidable through said body, and a piston on the piston rod in said cylinder, the improvement of a control device for regulating flow of oil under pressure into opposite ends of the cylinder for reciprocating the piston which comprises said piston rod having an axial recess communicating with the end head end of the cylinder, a control rod having one end freely movable in said recess and the other end slidable through said end head in sealed relation therewith, said control rod having opposed shoulders respectively outside of said end head and inside of said end head limiting sliding movement of the control rod through the end head, said control rod being pushed by fluid under pressure in the end head end of the cylinder to an extended position, means on the piston rod pulling the control rod to a retracted position, means on the end head holding the control rod in said retracted position whereby the rod is locked in fixed position except at the very ends of the stroke of the piston, and switch means tripped by the end of the control rod each time it is shifted by the piston rod.