US 6,189,432 B1Granted

Automotive lift hydraulic fluid control circuit

AssigneeHunter Engineering Company

InventorsNicholas Colarelli, Paul W. Roloff, Michael A. Olsen

Life of this patent

Estimating the term…

Loading patent…

Abstract

A hydraulic control circuit comprises a power unit, a central processing unit, at least one feedback sensor, a valve manifold, and two or more hydraulic lifting cylinders interconnected with miscellaneous hydraulic hoses and electrical wiring. Basic lifting is regulated by a flow divider unit configured to distribute a flow of pressurized hydraulic fluid pumped from a fluid reservoir through the valve manifold to each of the lifting cylinders during a lifting operation. To compensate for any imbalance between the lifting cylinders, the central processing unit monitors the movement of the lifting cylinders, and is configured to divert, through a three-way valve in the valve manifold, an additional portion of the pressurized fluid flow to a lagging lifting cylinder. During decent operations, the central processing unit extracts an additional portion of the fluid return flow through the three-way valve from a lagging lift cylinder, such that at all times during either lifting or decent operations, each lifting cylinder and a supported runway are disposed in a substantially parallel configuration.

Claims20

Dependent claims

A hydraulic fluid control system for an automotive vehicle lift structure comprising:

a source of hydraulic fluid;
two or more hydraulically actuated lifting components in fluid communication with said source of hydraulic fluid, said lifting components extending or retracting in a linear direction responsive to a flow of said hydraulic fluid to raise or lower said automotive vehicle lift structure;
a fluid flow divider valve having three ports interposed between said source of hydraulic fluid and said two or more hydraulically actuated lifting components, said first port in fluid communication with said source of hydraulic fluid, said second port in fluid communication with at least one of said lifting components, and said third port in fluid communication with at least one other of said lifting components, said flow divider valve configured to reversibly divide a fluid flow entering said first port into substantially equal portions exiting through said second and third ports;
a bi-directional fluid flow diverting valve interposed between said source of hydraulic fluid and said two or more hydraulically actuated lifting components, said fluid flow diverting valve configured to establish a fluid flow connection between a selected one of said lifting components and said source of hydraulic fluid, bypassing said fluid flow divider valve;
an electronic control unit responsive to said vertical elevation of said vehicle lift structure to select a lifting component and to control said bi-directional fluid flow diverting valve to establish a fluid connected between said source of hydraulic fluid and said selected lifting component.

2 more elements

A fluid flow control system for use with an automotive vehicle lift structure having two adjacent vehicle support members, comprising:

a source of fluid;
at least one fluid actuated lifting component associated with each vehicle support member, each of said lifting components configured to raise or lower said associated support member responsive to a flow of fluid between said lifting component and said source of fluid;
a bi-directional fluid flow divider/combiner circuit configured to regulate said fluid flow between said lifting components and said source of fluid;
a bi-directional fluid flow diverting valve interposed between said source of hydraulic fluid and each of said fluid actuated lifting components associated with said vehicle support members, said fluid flow diverting valve configured to establish a fluid flow connection between said lifting components associated with one of said vehicle support members and said source of hydraulic fluid, bypassing said fluid low divider/combiner circuit;
and
an electronic control circuit responsive to variations in vertical positioning between each of said vehicle support members to alter fluid flow configurations in said bi-directional fluid flow diverting value during ascending and descending motion of said vehicle support members, wherein additional fluid is supplied to said at least one lifting cylinder associated with a lagging vehicle support member during ascent and wherein additional flow is withdrawn from said at least one lifting cylinder associated with a lagging vehicle support member during descent.

3 more elements

Dependencies are inferred from the claim text.