Patent ID: 8522540

Claim:
A counterbalancing arrangement for counterbalancing two mutually movable parts that is arranged to counteract the gravitational force of at least one of said movable parts, said counterbalancing arrangement comprising a gas spring acting between said movable parts and a compressor system in fluid communication with said gas spring, said compressor system designed to sense a pressure in said gas spring and to adjust said pressure in said gas spring if said pressure deviates from a predetermined pressure value, said compressor system including a compressor and an automatic control system, said compressor and automatic control system designed to supply gas to said gas spring, remove gas from said gas spring, and combinations thereof so as to maintain said predetermined pressure value in said gas spring whenever said pressure in said gas spring deviates from said predetermined pressure value, said automatic control system including a pressure sensor and a pressure control valve, said pressure sensor designed to sense said pressure in said gas spring, said pressure control valve designed to regulate a flow of gas to said gas spring, from said gas spring, and combinations thereof, said automatic control system designed to control an operation of said compressor, said pressure control valve, and combinations thereof based on a signal from said pressure sensor, said compressor designed to be activated by said automatic control system and to cause fluid to be inserted into said gas spring when said pressure sensor senses apressure in said gas spring that is below said predetermined pressure, said compressor including a housing, a linear moving piston that is movable in said housing, and a valve that controls a flow of a fluid in said housing between a first and second fluid chamber within said housing as said piston moves in said housing.