摘要 |
A belt tensioner comprises a belt trained on a drive pulley driven by a drive unit mounted on a base supported on an air-spring bellows linearly extendable under fluid pressure from a collapsed position to an extended position to cause joint movement of the base, the drive unit and the drive pulley and thereby change the tension in the belt. A pressure regulator is operatively connected to the air-spring bellows for regulating the fluid pressure in the air-spring bellows such as to maintain the tension substantially constant in the belt during use.
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