US 4,743,037 A · Automatic levelling system

Abstract

A system for automatically levelling a vehicle, such as a recreational vehicle, relative to gravity includes a plurality of extensible jacks, preferably hydraulic, disposed at strategic positions on the vehicle underside. Switches sense the downward tilting of the vehicle relative to gravity at the strategic positions and produce signals to operate the jacks in accordance with such tilting. Before the jacks are extended, air bags in the vehicle are deflated. When the hydraulic pressure in a hydraulic circuit exceeds a first value, the jacks are extended in a particular sequence depending upon the particular directions in which the vehicle is tilted relative to gravity. A delay is preferably provided between the operations of each jack and the next jack in the sequence to eliminate transients in the next jack operation. When the vehicle has been levelled, jacks not previously extended are extended until they engage the ground with a second pressure less than the first pressure. Such jacks are extended by opening bleeder valves associated with such jacks and maintaining a relief valve closed. The pressure in such jacks is limited to the second particular pressure after such extension by closing the bleeder valve at such reduced pressure while opening the relief valve. While the vehicle is travelling, the hydraulic fluid in the jacks is slowly bled to a reservoir by opening the bleeder valves and the relief valve. In this way, hydraulic forces cannot accumulate in the jacks to the first particular pressure to operate the jacks.

Claims30

Dependent claims

In combination for use in a vehicle to level the vehicle relative to gravity,

a plurality of jacks each disposed on the vehicle at a strategic position on the vehicle and each being extensible to adjust the vertical disposition of the vehicle at the strategic position,
means operatively coupled to the jacks in the plurality for operating the jacks in a sequence to level the vehicle,
a plurality of bleeder valves each associated with an individual one of the jacks in the plurality,
a relief valve, and
means including the bleeder valves and the relief valve for obtaining an extension until the exertion of a particular pressure by the ground on particular ones of the jacks not previously extended in levelling the vehicle and for thereafter preventing such jacks form being extended,
the bleeder valves associated with the particular valves being opened during the extension of such jacks to obtain the imposition of the particular pressure on such jacks and the relief valve thereafter being opened.

3 more elements

In combination for use in a vehicle to level the vehicle relative to gravity,

a plurality of jacks disposed at strategic positions on the vehicle in operatively coupled relationship to the vehicle to support the vehicle on the ground, the jacks being extensible to adjust the positioning of the vehicle relative to gravity,
means for sensing the level of the vehicle at the strategic positions at each instant relative to gravity,
means responsive to the sensing means for obtaining extensions of the jacks in a particular sequence and through particular vertical distances to level the vehicle relative to gravity,
a relief valve,
a plurality of bleeder valves each associated with an individual one of the jacks, and
means including the relief valve and the bleeder valve for a particular one of the jacks in the plurality and responsive to a levelling of the jacks and a pressure less than a particular value in such particular one of the jacks for obtaining an operation of the bleeder valve and the relief valve in a first particular relationship to advance the particular jack until the particular jack receives the particular pressure and responsive to the particular pressure in the particular jack for obtaining an operation of the bleeder valve and the relief valve in a second particular relationship to prevent the pressure received by the particular jack from exceeding the particular value.

3 more elements

In combination for levelling a vehicle,

a plurality of jacks constructed to be coupled to the vehicle at the underside of the vehicle at strategic positions around the pariphery of the vehicle, each of the jacks being operative to raise or lower the vehicle relative to gravity at the strategic position at which is is disposed,
a support member,
a plurality of switches disposed on the support member, each of the switches having opened and closed states and each being positioned to indicate the downward tilting of the vehicle relative to gravity in the direction of an individual one of the jacks in the plurality,
means including the jacks and responsive to the closure of individual switches in the plurality and to particular pressures in the jacks for activating individual ones of the jacks in accordance with the individual closure of the switches to obtain a levelling of the vehicle,
a hydraulic relief valve,
a plurality of hydraulic bleeder valves each associated with an individual one of the jacks, and
means (i) establishing a first hydraulic circuit through the hydraulic relief valve and a particular one of the hydraulic bleeder valves in the plurality for providing an actuation of the particular jack associated with the particular bleeder valve when the particular jack experiences a pressure less than a particular value after the vehicle has been leveled and (ii) establishing a second hydraulic circuit through the hydraulic relief valve and the particular one of the hydraulic bleeder valves in the plurality when the particular bleeder valve experiences the particular pressure so as to prevent the pressure in the particular jack from experiencing a pressure greater than the particular pressure.

4 more elements

In combination for use in a vehicle to level the vehicle relative to gravity and for maintaining the vehicle fixedly in the leveled position relative to the ground,

a plurality of jacks constructed to be coupled to the vehicle at the underside of the vehicle at strategic positions around the periphery of the vehicle, each of the jacks being operative to raise or lower the vehicle relative to gravity at the strategic position at which it is disposed,
a support member,
a plurality of switches disposed on the support member, each of the switches having open and closed states and each being positioned to indicate the downward tilting of the vehicle relative to gravity in the direction of an individual one of the jacks in the plurality,
a plurality of first valves each connected in a first hydraulic circuit with an individual one of the jacks in the plurality and responsive to the closure of individual ones of the switches in the plurality for obtaining an operation of the associated jack to extend the associated jack to the ground with a first particular pressure produced by the ground against the jack,
a relief valve,
a plurality of bleeder valves each connected in a second circuit with an individual one of the jacks in the plurality and the relief valve for producing an extension to the ground of individual ones of the jacks not extended by the first hydraulic circuit until a second particular pressure is produced by the ground against the jack where the second particular pressure is less than the first particular pressure, and
a reservoir for hydraulic fluid,
the relief valve being connected in a third hydraulic circuit with the jacks to by-pass the first valves in the plurality and the bleeder valves in the plurality and introduce the fluid to the reservoir when the pressure of the fluid in the jacks reaches the second particular pressure.

5 more elements

Dependencies are inferred from the claim text.

Automatic levelling system

Life of this patent

Automatic levelling system

Life of this patent

Abstract

Claims30