Filter head

Claim 2

A filter head for use in a closed loop hydraulic circuit having a hydraulic fluid flow producing means and a hydraulic activated mechanism connected to each other by first and second flow lines, said filter head comprising: a filter means; a body portion having a first chamber for receiving hydraulic fluid from the first flow line, a second chamber for receiving hydraulic fluid from the second flow line, and an intermediate chamber having ports to and from said first and second chambers for receiving hydraulic fluid therefrom and having ports to and from said filter means for passing hydraulic fluid therethrough; first sliding check valve means in said first chamber for allowing fluid from the first flow line to pass through a first of said ports between said intermediate chamber and said first chamber, through said filter means, and back into said first chamber through a second of said ports when flow in the first flow line is towards the fluid flow producing means, and for allowing the fluid to bypass said intermediate chamber when flow in the first flow line is away from the fluid flow producing means; and second sliding check valve means in said second chamber for allowing fluid from the second flow line to pass through a first of said ports between said intermediate chamber and said second chamber, through said filter means, and back into said second chamber through a second of said ports when flow in the second flow line is towards the fluid flow producing means, and for allowing the fluid to bypass said intermediate chamber when flow in the second flow line is away from the fluid flow producing means.

Claim 3

The filter head of claim 1 in which each of said first and second sliding check valve means comprises: a hollow housing portion having a first port and a second port, said housing portion being slidable from an open position in which said first and second ports are aligned with said first and second ports between either of said first and second chambers and said intermediate chamber to a closed position in which said first and second ports are disaligned with said first and second ports between either of said first and second chambers and said intermediate chamber, an open partition in said hollow housing portion intermediate said first and second ports, a plug means having an open position away from said open partition for allowing the fluid to flow therethrough and having a closed position adjacent said open partition for prohibiting the fluid from flowing therethrough, a first spring for biasing said housing portion in the closed position, and a second spring for biasing said plug means in the closed position.

Claim 4

The filter head of claim 2 which is provided with a third set of ports between said first and second chambers and said intermediate chamber and said hollow housing portion of either first or second sliding check valve means is slidable from said open and closed positions to a bypass position in which said first and second ports of said housing portion are aligned with said second and third ports between either of said first and second chambers and said intermediate chamber for allowing the hydraulic fluid to bypass said filter means when flow is towards the fluid flow producing means and when pressure in said first and second chambers has passed a certain point.

Claim 5

The filter head of claim 1 in which said intermediate chamber includes a closed partition between said port to said filter means and said port from said filter means for requiring all of the hydraulic fluid entering said intermediate chamber from said first of said ports between said intermediate chamber and either of said first and second chambers to flow through said filter means.

Claim 6

The filter head of claim 1 in which said intermediate chamber includes check valve means between said port to said filter means and said port from said filter means for allowing the hydraulic fluid entering said intermediate chamber from said first of said ports between said intermediate chamber and either of said first and second chambers to partially bypass said filter means when the pressure in said filter head has passed a certain point.

Claim 7

The filter head of claim 1 in which is included manifold means adjacent said body portion, said manifold means comprising: a shell portion having first and second chambers for receiving the hydraulic fluid from said first and second chambers of said body portion, a high pressure chamber for receiving the hydraulic fluid from either of said first or second chambers when the pressure in either of said first or second chambers passes a certain point, and a charge pressure chamber for allowing the injection of hydraulic fluid into said first and second chambers from a supply source outside the circuit; first check valve means between said first chamber and said high pressure chamber for allowing the hydraulic fluid to pass from said first chamber to said high pressure chamber when the pressure in said first chamber has passed a certain point; second check valve means between said second chamber and said high pressure chamber for allowing the hydraulic fluid to pass from said second chamber to said high pressure chamber when the pressure in said second chamber has passed a certain point; third and fourth check valve means between said first and second chambers and said charge pressure chamber for allowing hydraulic fluid to pass from said charge pressure chamber to said first and second chambers when the pressure in said charge pressure chamber has passed a certain point; and fifth check valve means between said high pressure chamber and said charge pressure chamber for allowing the hydraulic fluid to pass from said high pressure chamber to said charge pressure chamber when the pressure in said high pressure chamber has passed a certain point.

Claim 8

A filter head for use in a closed loop hydraulic circuit having a hydraulic fluid flow producing means and a hydraulic activated mechanism connected to each other by first and second flow lines, said filter head comprising: a filter means; a body portion having a first chamber for receiving hydraulic fluid from the first flow line, and an intermediate chamber having ports to and from said first and second chambers for receiving hydraulic fluid therefrom and having ports to and from said filter means for passing hydraulic fluid therethrough, said intermediate chamber including a closed partition between said ports to and from said filter means for requiring all of the hydraulic fluid entering said intermediate chamber from a first of said ports between said intermediate chamber and said first chamber and from a first of said ports between said intermediate chamber and said second chamber to flow through said filter means; first sliding check valve means in said first chamber for allowing fluid from the first flow line to pass through said first of said ports between said intermediate chamber and said first chamber, through said filter means, and back into said first chamber through a second of said ports when flow is towards the fluid flow producing means, for allowing the fluid to pass into said intermediate chamber through said second of said ports between said intermediate chamber and said first chamber and back into said first chamber through a third of said ports when flow is toards the fluid flow producing means and when pressure in said first chamber has passed a certain point, and for allowing the fluid to bypass said intermediate chamber when flow is away from the fluid flow producing means; second sliding check valve means in said second chamber for allowing fluid from the second flow line to pass through said first of said ports between said intermediate chamber and said second chamber, through said filter means, and back into said second chamber through a second of said ports when Flow is toward the fluid flow producing means, for allowing the fluid to pass into said intermediate chamber through said second of said ports between said intermediate chamber and said second chamber and back into said second chamber through a third of said ports when flow is towards the fluid flow producing means and when pressure in said second chamber has passed a certain point, and for allowing the fluid to bypass said intermediate chamber when flow is away from the fluid flow producing means; and manifold means adjacent said body portion, said manifold means having first and second chambers for receiving the hydraulic fluid from said first and second chambers of said body portion, a high pressure chamber for receiving the hydraulic fluid when the pressure in said first or second chamber passes a certain point, and a charge pressure chamber for allowing the injection of hydraulic fluid into said first and second chambers from a supply source outside the circuit.

Claim 9

A filter head for use in a closed loop hydraulic circuit having a hydraulic fluid flow producing means and a hydraulic activated mechanism connected to each other by first and second flow lines, said filter head comprising: a filter means; a body portion having a first chamber for receiving hydraulic fluid from the first flow line, and an intermediate chamber having ports to and from said first and second chambers for receiving hydraulic fluid therefrom and having ports to and from said filter means for passing hydraulic fluid therethrough, said intermediate chamber including a closed partition between said ports to and from said filter means for requiring all of the hydraulic fluid entering said intermediate chamber from a first of said ports between said intermediate chamber and said first chamber and from a first of said ports between said intermediate chamber and said second chamber to flow through said filter means; first sliding check valve means in said first chamber for allowing fluid from the first flow line to pass through said first of said ports between said intermediate chamber and said first chamber, through said filter means, and back into said first chamber through a second of said ports when flow is towards the fluid flow producing means, for allowing the fluid to pass into said intermediate chamber through said second of said ports between said intermediate chamber and said first chamber and back into said first chamber through a third of said ports when flow is toards the fluid flow producing means and when pressure in said first chamber has passed a certain point, and for allowing the fluid to bypass said intermediate chamber when flow is away from the fluid flow producing means; second sliding check valve means in said second chamber for allowing fluid from the second flow line to pass through said first of said ports between said intermediate chamber and said second chamber, through said filter means, and back into said second chamber through a second of said ports when Flow is toward the fluid flow producing means, for allowing the fluid to pass into said intermediate chamber through said second of said ports between said intermediate chamber and said second chamber and back into said second chamber through a third of said ports when flow is towards the fluid flow producing means and when pressure in said second chamber has passed a certain point, and for allowing the fluid to bypass said intermediate chamber when flow is away from the fluid flow producing means; and manifold means adjacent said body portion, said manifold means having first and second chambers for receiving the hydraulic fluid from said first and second chambers of said body portion, a high pressure chamber for receiving the hydraulic fluid when the pressure in said first or second chamber passes a certain point, and a charge pressure chamber for allowing the injection of hydraulic fluid into said first and second chambers from a supply source outside the circuit.

Claim 10

The combination with a closed loop hydraulic circuit having a hydraulic fluid flow producing means and a hydraulic activated mechanism connected to each other by first and second flow lines of a filter head, said filter head comprising: a filter means; a body portion having a first chamber for receiving hydraulic fluid from the first flow line, a second chamber for receiving hydraulic fluid from the second flow line, and an intermediate chamber having ports to and from said first and second chambers for receiving hydraulic fluid therefrom and having ports to and from said filter means for passing hydraulic fluid therethrough, said intermediate chamber including a closed partition between said ports to and from said filter means for requiring all of the hydraulic fluid entering said intermediate chamber from a first of said ports between said intermediate chamber and said first chamber and from a first of said ports between said intermediate chamber and said second chamber to flow through said filter means; first sliding check valve means in said first chamber for allowing fluid from the first flow line to pass through said first of said ports between said intermediate chamber and said first chamber, through said filter means, and back into said first chamber through a second of said ports when flow is towards the fluid flow producing means, for allowing the fluid to pass into said intermediate chamber through said second of said ports between said intermediate chamber and said first chamber and back into said first chamber through a third of said ports when flow is towards the fluid flow producing means and when pressure in said first chamber has passed a certain point, and for allowing the fluid to bypass said intermediate chamber when flow is away from the fluid flow producing means; second sliding check valve means in said second chamber for allowing fluid from the second flow line to pass through said first of said ports between said intermediate chamber and said second chamber, through said filter means, and back into said second chamber through a second of said ports when flow is toward the fluid flow producing means, for allowing the fluid to pass into said intermediate chamber through said second of said ports between said intermediate chamber and said second chamber and back into said second chamber through a third of said ports when flow is towards the fluid flow producing means and when pressure in said second chamber has passed a certain point, and for allowing the fluid to bypass said intermediate chamber when flow is away from the fluid flow producing means; and manifold means adjacent said body portion, said manifold means having first and second chambers for receiving the hydraulic fluid from said first and second chambers of said body portion, a high pressure chamber for receiving the hydraulic fluid when the pressure in said first or second chamber passes a certain point, and a charge pressure chamber for allowing the injection of hydraulic fluid into said first and second chambers from a supply source outside the circuit.

Claim 11

The combination with a closed loop hydraulic circuit having a hydraulic fluid flow producing means and a hydraulic activated mechanism connected to each other by first and second flow lines of a filter head, said filter head comprising: a filter means; a body portion having a first chamber for receiving hydraulic fluid from the first flow line, a second chamber for receiving hydraulic fluid from the second flow line, and an intermediate chamber having ports to and from said first and second chambers for receiving hydraulic fluid therefrom and having ports to and from said filter means for passing hydraulic fluid therethrough, said intermediate chamber including a closed partition between said ports to and from said filter means for requiring all of the hydraulic fluid entering said intermediate chamber from a first of said ports between said intermediate chamber and said first chamber and from a first of said ports between said intermediate chamber and said second chamber to flow through said filter means; first sliding check valve means in said first chamber for allowing fluid from the first flow line to pass through said first of said ports between said intermediate chamber and said first chamber, through said filter means, and back into said first chamber through a second of said ports when flow is towards the fluid flow producing means, for allowing the fluid to pass into said intermediate chamber through said second of said ports between said intermediate chamber and said first chamber and back into said first chamber through a third of said ports when flow is towards the fluid flow producing means and when pressure in said first chamber has passed a certain point, and for allowing the fluid to bypass said intermediate chamber when flow is away from the fluid flow producing means; second sliding check valve means in said second chamber for allowing fluid from the second flow line to pass through said first of said ports between said intermediate chamber and said second chamber, through said filter means, and back into said second chamber through a second of said ports when flow is toward the fluid flow producing means, for allowing the fluid to pass into said intermediate chamber through said second of said ports between said intermediate chamber and said second chamber and back into said second chamber through a third of said ports when flow is towards the fluid flow producing means and when pressure in said second chamber has passed a certain point, and for allowing the fluid to bypass said intermediate chamber when flow is away from the fluid flow producing means; and manifold means adjacent said body portion, said manifold means having first and second chambers for receiving the hydraulic fluid from said first and second chambers of said body portion, a high pressure chamber for receiving the hydraulic fluid when the pressure in said first or second chamber passes a certain point, and a charge pressure chamber for allowing the injection of hydraulic fluid into said first and second chambers from a supply source outside the circuit.