Automatic levelling arrangement for vehicles and the like

Claim 2

In a distance-regulating arrangement for controlling the spacing between two components that are to be subjected to varying forces tending to change the spacing between the components, particularly for controlling the spacing between an axle and the chassis of a vehicle subjected to varying weight forces, in combination, linkage means for connecting together said two components and including a first portion connectable to one of said two components and a second portion connectable to the other of said two components and movable relative to said first portion of said linkage means in a predetermined direction, said linkage means being subjected to a loading force varying between a lower limit and an upper limit; detecting means operative for detecting whether the loading force applied to said linkage means is in a first range bounded by said lower limit and by a predetermined first value greater than said lower limit, in a second range bounded by said first value and by a predetermined second value greater than said first value but lower than said upper limit, or in a predetermined third range bounded by said second value and by said upper limit; and control means operative when said loading force is in said second range for automatically restoring said distance to a predetermined normal value when said distance departs from said normal value but operative when said loading force is in either one of said first and third ranges for automatically changing said distance as a predetermined function of the magnitude of said loading force.

Claim 3

An arrangement as defined in claim 1, wherein said linkage means comprises a hydraulic cylinder and piston unit including a hydraulic cylinder constituting said first portion and a hydraulic piston constituting said second portion, and wherein said control means comprises hydraulic means automatically operative for increasing and decreasing the pressure of hydraulic fluid in said cylinder to apply to said hydraulic piston a hydraulic force resisting the effect of said loading force, but only when said loading force is intermediate said first and second values.

Claim 4

An arrangement as defined in claim 2, wherein said control means further includes spring means connected to said first and second portions and operative for resisting said loading force.

Claim 5

An arrangement as defined in claim 2, wherein said control means further includes spring means so conected to said first and second portions as to supplement the hydraulic force exerted upon said hydraulic cylinder by said hydraulic means when said loading force is intermediate said first and second values.

Claim 6

An arrangement as defined in claim 4, wherein said piston divides the interior of said cylinder into two axially spaced chambers, and wherein said piston is provided with a piston rod connected to one axial end of said piston, with the other axial end of said piston having a larger area exposed to pressurized hydraulic fluid than does said one axial end thereof, and wherein said hydraulic means comprises a pump communicating with the interior of said cylinder and operative for pumping pressure fluid into said cylinder to increase the pressure of fluid in said cylinder, and outlet valve means communicating with the interior of said cylinder and operative when actuated for permitting the flow of pressure fluid out of said cylinder to decrease the pressure of fluid in said cylinder, and wherein said hydraulic means further includes first pressure-responsive means operative for prevEnting the flow of fluid out of said cylinder through said outlet valve means when the pressure of fluid in said cylinder falls below the pressure required to maintain said distance at said normal value under a loading force having said first value, and second pressure-responsive means operative for preventing further increase of pressure in said cylinder when the pressure in said cylinder exceeds the value required to maintain said predetermined distance between said portions under a loading force having said second value.

Claim 7

An arrangement as defined in claim 5, wherein said second pressure-responsive means comprises means operative for terminating operation of said pump means when the pressure in said cylinder exceeds the value required to maintain said predetermined distance between said portions under a loading force having said second value.

Claim 8

An arrangement as defined in claim 5, wherein said hydraulic means further comprises an outlet conduit communicating with the interior of said cylinder and controlled by said outlet valve means, and wherein said first pressure-responsive means comprises means operative for blocking said outlet conduit at a portion thereof downstream of said outlet valve means when the pressure in said outlet conduit falls below the cylinder pressure required to maintain said predetermined distance between said portions under a loading force having said first value.

Claim 9

An arrangement as defined in claim 1, wherein said control means comprises spring means connected to said first and second portions and operative for resisting the loading force for all values of said loading force intermediate said lower and upper limits, and further includes hydraulic means automatically operative for supplementing the resisting force afforded by said spring means and furthermore automatically operative only when said loading force is intermediate said first and second values for maintaining substantially constant the distance between said first and second portions.

Claim 10

In combination with a vehicle having a wheel axle and a chassis, a distance-regulating arrangement for controlling the spacing between said wheel axle and said chassis in response to weight forces, comprising linkage means including a first portion connected to said chassis and a second portion connected to said axle and movable relative to said first portion of said linkage means in a predetermined direction, said linkage means being subjected to a varying load force which varies between a lower limit and an upper limit; detecting means operative for detecting whether the loading force applied to said linkage means is in a first range bounded by said lower limit and by a predetermined first value greater than said lower limit, in a second range bounded by said first value and by a predetermined second value greater than said first value but lower than said upper limit, or in a third range bounded by said second value and by said upper limit; and control means operative when said loading force is in said second range for automatically restoring said distance to a predetermined normal value when said distance deviates from said normal value but operative when said loading force is in either one of said first and third ranges for automatically changing said distance as a predetermined function of the magnitude of said loading force.

Claim 11

In combination with a vehicle having a wheel axle and a chassis, a distance-regulating arrangement for controlling the spacing between said wheel axle and said chassis in response to weight forces, comprising linkage means including a first portion connected to said chassis and a second portion connected to said axle and movable relative to said first portion of said linkage means in a predetermined direction, said linkage means being subjected to a varying load force which varies between a lower limit and an upper limit; detecting means operative for detecting whether the loading force applied to said linkage means is in a first range bounded by said lower limit and by a predetermined first value greater than said lower limit, in a second range bounded by said first value and by a predetermined second value greater than said first value but lower than said upper limit, or in a third range bounded by said second value and by said upper limit; and control means operative when said loading force is in said second range for automatically restoring said distance to a predetermined normal value when said distance deviates from said normal value but operative when said loading force is in either one of said first and third ranges for automatically changing said distance as a predetermined function of the magnitude of said loading force.

Claim 12

In a vehicle comprised of a chassis having a first end and a second end, a first axle arrangement at said first end and a second axle arrangement at said second end, and a mounting arrangement for mounting said first end of said chassis on said first axle arrangement and said second end of said chassis on said second axle arrangement, the mounting arrangement being of the type operative for automatically regulating the spacing between said first end of said chassis and said first axle arrangement by restoring said spacing to a predetermined value when due to a change in loading force said spacing deviates from said value but without similarly regUlating the spacing between said second end of said chassis and said second axle arrangement, so as to cause the possibility of discrepancies between the elevation of the first end of said chassis and the elevation of the second end of said chassis, the improvement residing in the fact that the mounting arrangement comprises linkage means including a first portion connected to said first end of said chassis and including a second portion connected to said first axle arrangement and movable relative to said first portion of said linkage means in a predetermined direction, said linkage means being subjected to a loading force varying between a lower limit corresponding to the absence of passengers and cargo in said vehicle and an upper limit corresponding to full loading of the vehicle; detecting means operative for detecting when the loading force applied to said linkage means is in a predetermined first range bounded by said lower limit and by a predetermined first value greater than said lower limit, in a predetermined second range bounded by said first value and by a predetermined second value greater than said first value but lower than said upper limit, or in a predetermined third range bounded by said second value and by said upper limit; and control means operative when said loading force is in one of said first and third ranges for causing the distance between said portions to vary as a predetermined function of said loading force within a range of values above a predetermined normal value of said distance, operative when said loading force is in the other one of said first and third ranges for causing said distance to vary as a predetermined function of said loading force within a range of values of said distance below said normal value, and operative when said loading force is in said second range for automatically restoring said distance to said normal value when said distance deviates from said normal value.

Claim 13

In a vehicle comprised of a chassis having a first end and a second end, a first axle arrangement at said first end and a second axle arrangement at said second end, and a mounting arrangement for mounting said first end of said chassis on said first axle arrangement and said second end of said chassis on said second axle arrangement, the mounting arrangement being of the type operative for automatically regulating the spacing between said first end of said chassis and said first axle arrangement by restoring said spacing to a predetermined value when due to a change in loading force said spacing deviates from said value but without similarly regUlating the spacing between said second end of said chassis and said second axle arrangement, so as to cause the possibility of discrepancies between the elevation of the first end of said chassis and the elevation of the second end of said chassis, the improvement residing in the fact that the mounting arrangement comprises linkage means including a first portion connected to said first end of said chassis and including a second portion connected to said first axle arrangement and movable relative to said first portion of said linkage means in a predetermined direction, said linkage means being subjected to a loading force varying between a lower limit corresponding to the absence of passengers and cargo in said vehicle and an upper limit corresponding to full loading of the vehicle; detecting means operative for detecting when the loading force applied to said linkage means is in a predetermined first range bounded by said lower limit and by a predetermined first value greater than said lower limit, in a predetermined second range bounded by said first value and by a predetermined second value greater than said first value but lower than said upper limit, or in a predetermined third range bounded by said second value and by said upper limit; and control means operative when said loading force is in one of said first and third ranges for causing the distance between said portions to vary as a predetermined function of said loading force within a range of values above a predetermined normal value of said distance, operative when said loading force is in the other one of said first and third ranges for causing said distance to vary as a predetermined function of said loading force within a range of values of said distance below said normal value, and operative when said loading force is in said second range for automatically restoring said distance to said normal value when said distance deviates from said normal value.

Claim 14

In combination with a vehicle having a wheel axle and a chassis, a distance-regulating arrangement for controlling the spacing between said wheel axle and said chassis, comprising linkage means including a first portion connected to said chassis and a second portion connected to said axle and movable relative to said first portion of said linkage means in a predetermined direction, said linkage means being subjected to a loading force which varies between a lower limit corresponding to the absence of passengers and cargo in said vehicle and an upper limit corresponding to full loading of the vehicle; detecting means operative for determining whether the magnitude of the loading force lies within a first range bounded by said lower limit and by a predetermined intermediate value intermediate said lower limit and said upper limit, or in a second range bounded by said intermediate value and by said upper limit; and control means operative when the magnitude of the loading force lies within said first range for automatically changing the distance between said portions as a predetermined function of the magnitude of the loading force but operative when the magnitude of the loading force lies within said second range for automatically restoring said distance to a predetermined normal value when said distance deviates from said normal value.

Claim 15

In combination with a vehicle having a wheel axle and a chassis, a distance-regulating arrangement for controlling the spacing between said wheel axle and said chassis, comprising linkage means including a first portion connected to said chassis and a second portion connected to said axle and movable relative to said first portion of said linkage means in a predetermined direction, said linkage means being subjected to a loading force which varies between a lower limit corresponding to the absence of passengers and cargo in said vehicle and an upper limit corresponding to full loading of the vehicle; detecting means operative for determining whether the magnitude of the loading force lies within a first range bounded by said lower limit and by a predetermined intermediate value intermediate said lower limit and said upper limit, or in a second range bounded by said intermediate value and by said upper limit; and control means operative when the magnitude of the loading force lies within said first range for automatically changing the distance between said portions as a predetermined function of the magnitude of the loading force but operative when the magnitude of the loading force lies within said second range for automatically restoring said distance to a predetermined normal value when said distance deviates from said normal value.

Claim 16

In combination with a vehicle having a wheel axle and a chassis, a distance-regulating arrangement for controlling the spacing between said wheel axle and said chassis, comprising linkage means including a first portion connected to said chassis and a second portion connected to said axle and movable relative to said first portion of said linkage means in a predetermined direction, said linkage means being subjected to a loading force which varies between a lower limit corresponding to the absence of passengers and cargo in said vehicle and an upper limit corresponding to full loading of the vehicle; detecting means operative for determining whether the magnitude of the loading force lies within the first range bounDed by a first intermediate value intermediate said lower limit and said upper limit and by a second intermediate value intermediate said first intermediate value and said upper limit, or within a second range intermediate said second intermediate value and said upper limit; and control means operative when the magnitude of the loading force lies within said second range for automatically changing the distance between said portions as a predetermined function of the magnitude of the loading force and operative when the magnitude of the loading force lies within said first range for automatically restoring said distance to a predetermined normal value when said distance deviates from said normal value.

Claim 17

In combination with a vehicle having a wheel axle and a chassis, a distance-regulating arrangement for controlling the spacing between said wheel axle and said chassis, comprising linkage means including a first portion connected to said chassis and a second portion connected to said axle and movable relative to said first portion of said linkage means in a predetermined direction, said linkage means being subjected to a loading force which varies between a lower limit corresponding to the absence of passengers and cargo in said vehicle and an upper limit corresponding to full loading of the vehicle; detecting means operative for determining whether the magnitude of the loading force lies within the first range bounDed by a first intermediate value intermediate said lower limit and said upper limit and by a second intermediate value intermediate said first intermediate value and said upper limit, or within a second range intermediate said second intermediate value and said upper limit; and control means operative when the magnitude of the loading force lies within said second range for automatically changing the distance between said portions as a predetermined function of the magnitude of the loading force and operative when the magnitude of the loading force lies within said first range for automatically restoring said distance to a predetermined normal value when said distance deviates from said normal value.

Claim 18

In a vehicle comprised of a chassis having a first end and a second end, a first axle arrangement at said first end and a second axle arrangement at said second end, and a mounting arrangement for mounting said first end of said chassis on said first axle arrangement and said second end of said chassis on said second axle arrangement, the mounting arrangement being of the type operative for automatically regulating the spacing between said first end of said chassis and said first axle arrangement by restoring said spacing to a predetermined value when due to a change in loading force said spacing deviates from said value but without similarly regulating the spacing between said second end of said chassis and said second axle arrangement, the improvement residing in the fact that the mounting arrangement comprises a variable-length hydraulic cylinder-and-piston linkage unit having a first portion connected to said first axle arrangement and a second portion connected to said first end of said chassis, said linkage unit being subjected to a weight loading force varying between a lower limit corresponding to the absence of passengers and cargo in said vehicle and an upper limit corresponding to full loading of the vehicle; a working fluid reservoir; a pump having an inlet connected to said reservoir and having an outlet; a first conduit connecting the outlet of said reservoir to the interior of said hydraulic linkage unit; a second conduit connecting the interior of said hydraulic linkage unit to said reservoir; means operative, when the distance between said first and second portions of said linkage unit deviates in a predetermined direction from a preselected normal value, for automatically restoring said distance to said normal value by causing said pump to pump working fluid from said reservoir through said first conduit into the interior of said linkage unit; means operative for automatically terminating the pumping of working fluid through said first conduit into the interior of said linkage unit when the pressure of working fluid being pumped into the interior of said linkage unit exceeds a predetermined pressure corresponding to a loading force having a predetermined first value greater than said lower limit; means operative when the distance between said first and second portions of said linkage unit deviates in the opposite direction from said normal value for automatically restoring said distance to said normal value by automatically causing working fluid to flow from the interior of said linkage unit into said reservoir through said second conduit; means operative for automatically terminating the flow of working fluid out from the interior of said linkage unit into said reservoir through said second conduit when the pressure of working fluid in said second conduit falls below a predetermined pressure corresponding to a loading force having a predetermined second value greater than said first value but less than said upper limit; and auxiliary mechanical spring means connecting together said first and second portions of said linkage unit and operative for supplementing the resisting force developed by said hydraulic linkage unit when the loading force applied to said linkage unit has a value intermediate said lower limit and said first value and also when the loading force applied to said linkage unit has a value intermediate said second value and said upper limit.

Claim 19

In a vehicle comprised of a chassis having a first end and a second end, a first axle arrangement at said first end and a second axle arrangement at said second end, and a mounting arrangement for mounting said first end of said chassis on said first axle arrangement and said second end of said chassis on said second axle arrangement, the mounting arrangement being of the type operative for automatically regulating the spacing between said first end of said chassis and said first axle arrangement by restoring said spacing to a predetermined value when due to a change in loading force said spacing deviates from said value but without similarly regulating the spacing between said second end of said chassis and said second axle arrangement, the improvement residing in the fact that the mounting arrangement comprises a variable-length hydraulic cylinder-and-piston linkage unit having a first portion connected to said first axle arrangement and a second portion connected to said first end of said chassis, said linkage unit being subjected to a weight loading force varying between a lower limit corresponding to the absence of passengers and cargo in said vehicle and an upper limit corresponding to full loading of the vehicle; a working fluid reservoir; a pump having an inlet connected to said reservoir and having an outlet; a first conduit connecting the outlet of said reservoir to the interior of said hydraulic linkage unit; a second conduit connecting the interior of said hydraulic linkage unit to said reservoir; means operative, when the distance between said first and second portions of said linkage unit deviates in a predetermined direction from a preselected normal value, for automatically restoring said distance to said normal value by causing said pump to pump working fluid from said reservoir through said first conduit into the interior of said linkage unit; means operative for automatically terminating the pumping of working fluid through said first conduit into the interior of said linkage unit when the pressure of working fluid being pumped into the interior of said linkage unit exceeds a predetermined pressure corresponding to a loading force having a predetermined first value greater than said lower limit; means operative when the distance between said first and second portions of said linkage unit deviates in the opposite direction from said normal value for automatically restoring said distance to said normal value by automatically causing working fluid to flow from the interior of said linkage unit into said reservoir through said second conduit; means operative for automatically terminating the flow of working fluid out from the interior of said linkage unit into said reservoir through said second conduit when the pressure of working fluid in said second conduit falls below a predetermined pressure corresponding to a loading force having a predetermined second value greater than said first value but less than said upper limit; and auxiliary mechanical spring means connecting together said first and second portions of said linkage unit and operative for supplementing the resisting force developed by said hydraulic linkage unit when the loading force applied to said linkage unit has a value intermediate said lower limit and said first value and also when the loading force applied to said linkage unit has a value intermediate said second value and said upper limit.