Patent ID: 7867151

Claim:
An apparatus connected to a source of pressurized gas and connected to a piece of exercise equipment, for providing and maintaining a user-selected magnitude of force for the purpose of countering a force imposed by the user against a unilateral lifting bar of the exercise equipment to induce or resist movement of the lifting bar relative to a fixed frame of the equipment throughout the range of movement of the lifting bar actuated by the user, comprising, a pneumatic piston-cylinder assembly for providing such resistance, connected between the lifting bar and the fixed frame of the exercise equipment, said assembly including a cylinder with a hollow interior and with first and second ends, a piston moveably disposed in said interior of said cylinder between said first and second ends, separating said interior of said cylinder into a first space between said first end of said cylinder and said piston and a second space between said piston and said second end of said cylinder, a piston rod with first and second ends, connected at said first end to said piston and extending through said second end of said cylinder with said second end of said piston rod disposed outside said cylinder, and a gas passageway connecting between said interior and the exterior of said cylinder; a pressure transducer connected in gas flow relationship to said gas passageway of said cylinder so as to allow the communication of gas pressure between said cylinder and said transducer, said transducer including signal generating means for generating an electrical signal in response to and proportional to the gas pressure communicated to said transducer; an electrically controlled and operated gas flow regulator connected in gas flow relationship to the source of pressurized gas, and connected in an interruptible gas flow relationship to said cylinder so as to allow the flow of gas from the source of pressurized gas to said cylinder through said regulator with said regulator in an open position and block said flow of gas with said regulator in a closed position, said regulator also having a gas outlet for the venting of pressurized gas therefrom with said regulator in a vent position, the position of said regulator set in response to electrical control signals received by said regulator; and an adjustable potentiometer electrically connected to said transducer and electrically connected to said regulator for the purpose of controlling said regulator so as to allow pressurized gas to flow from the source of pressurized gas to said regulator and from said regulator to said cylinder to increase the gas pressure in said cylinder, so as to allow gas to flow from said cylinder to said regulator and be released from said regulator to reduce the gas pressure in said cylinder, and so as to prevent the flow of gas through or from said regulator to maintain the gas pressure in said cylinder, in accordance with the setting of said potentiometer and in response to the electrical signal received therefrom.