Automatic control of lockable differentials

Claim 2

In a control circuit for use in controlling a lockable differential having a manually controlled system including a pressure supply means, a manually operated valve, a one way check valve, a lockable differential and first conduit means providing a means for communicating pressure from the pressure supply means to the differential through the manually operated valve and the one way check valve, the improvement comprising an automatically engaged differential locking system comprising: a peripheral equipment control lever; a multi position normally closed control valve being operatively linked to the peripheral equipment control lever; a second one way check valve permitting flow in one direction; second conduit means allowing communication between the pressure supply means and the lockable differential through the multiposition normally closed control valve and the second one way check valve whereby displacement of the peripheral equipment control lever will result in the opening of the multiposition normally closed control valve thus resulting in transmission of pressure from the pressure supply means to lock the lockable differential.

Claim 3

The invention in accordance with claim 1 wherein the pressure supply means is a gas supply reservoir and the control circuit depends on gas pressure to lock up the lockable differential.

Claim 4

The invention in accordance with claim 1 wherein the pressure supply means is a source of hydraulic fluid and the control circuit depends on hydraulic fluid pressure to lock up the lockable differential.

Claim 5

The invention in accordance with claim 1 wherein the multipositional normally closed control valve is a spool type valve having a first position allowing flow through the valve, a second position blocking flow through the valve and the third position allowing flow through the valve.

Claim 6

The invention in accordance with claim 1 wherein the peripheral equipment control device is an elevator control valve having load, off and reverse positions and is further operatively communicative with an actuator cylinder for controlling an elevator hydraulic valve.

Claim 7

The invention in accordance with claim 1 wherein the differential locking system further comprises; a first and a second inversion valve, each inversion valve normally closed having a supply port receiving fluid from the supply source of fluid pressure, a control port receiving a pressure signal, a delivery port allowing fluid pressure to be communicated to the lockable differential and an exhaust port; second conduit means allowing fluid communication between the peripheral control device and the inversion valves, the supply source of fluid and the inversion valves, and the inversion valves and the lockable differential which also contains the first one way check valve.

Claim 8

In combination with a control circuit for use in controlling a lockable differential having a manually controlled system including a supply source of fluid pressure, of one of either of gas or liquid, a manually operated valve, a first one way check valve, a locking clutch for locking the lockable differential and first conduit means providing a means for communicating fluid from the supply source of fluid pressure to the lockable differential through the manually operated valve and the one way check valve, the improvement comprising: a peripheral equipment control mechanism; a peripheral equipment operating mechanism of a cylinder and a piston where the piston may be displaced by fluid pressure; a normally closed inversion valve having a supply port receiving fluid from the supply source of fluid pressure, a central port receiving a pressure signal, a delivery port allowing fluid pressure to be communicated to the lockable differential and an exhaust port; a second one way check valve allowing fluid to be delivered to the lockable differential; and second conduit means allowing fluid communication between the peripheral equipment control mechanism and the inversion valve, and the inversion valve and the lockable differential which also contains the second one way check valve whereby the lockable differential will be caused to be locked when the peripheral equipment operating mechanism interrupts the fluid flow from the supply source of fluid which results in the inversion valve allowing the passage of fluid from the supply source to the locking clutch of the lockable differential.

Claim 9

In combination with a control circuit for use in controlling a lockable differential having a manually controlled system including a supply source of fluid pressure, of one of either of gas or liquid, a manually operated valve, a first one way check valve, a locking clutch for locking the lockable differential and first conduit means providing a means for communicating fluid from the supply source of fluid pressure to the lockable differential through the manually operated valve and the one way check valve, the improvement comprising: a peripheral equipment control mechanism; a peripheral equipment operating mechanism of a cylinder and a piston where the piston may be displaced by fluid pressure; a normally closed inversion valve having a supply port receiving fluid from the supply source of fluid pressure, a central port receiving a pressure signal, a delivery port allowing fluid pressure to be communicated to the lockable differential and an exhaust port; a second one way check valve allowing fluid to be delivered to the lockable differential; and second conduit means allowing fluid communication between the peripheral equipment control mechanism and the inversion valve, and the inversion valve and the lockable differential which also contains the second one way check valve whereby the lockable differential will be caused to be locked when the peripheral equipment operating mechanism interrupts the fluid flow from the supply source of fluid which results in the inversion valve allowing the passage of fluid from the supply source to the locking clutch of the lockable differential.