Force adjusting device

A force adjusting device for adjusting a spring-generated biasing force on a movable component relative to a second component, comprising:

• a housing adapted for attachment to the second component;
• a spring operably mounted to the housing, the spring having a first end adapted to engage the movable component and having a second end;
• a hub engaging the second end that is configured to change a position of the second end to adjust a tension of the spring;
• a handle for rotating the hub;
• and
• a clutch operably attached to the hub and the handle that is constructed to lock when a biasing force is received from the spring and the movable component, but configured to release and allow movement of the handle and the hub to adjust a tension of the spring when the handle is manipulated.

A force adjusting device for adjusting a spring-generated biasing force on a movable component relative to a second component, comprising:

• a housing adapted for attachment to the second component, the housing including a ring gear;
• a spring operably mounted to the housing, the spring having a first end adapted to engage the movable component and having a second end;
• a gear arrangement engaging the second end and the ring gear that is configured to change a position of the second end with mechanical advantage to adjust a tension of the spring;
• and
• a handle operably attached to the gear arrangement for operating the gear arrangement, whereby the handle can be manipulated to operate the gear arrangement to adjust a tension of the spring.

A chair comprising:

• a back frame;
• a flexible back support operably supported on the back frame, the flexible back support including a flexible lumbar region and a flanged bracket pivotally connected to the back frame at a back pivot;
• and
• a force adjusting device attached to the back frame at the back pivot for adjusting a spring-generated torsional biasing force on the flanged bracket relative to the back frame, the force adjusting device including:
• a housing adapted for attachment to the back frame, the housing including a ring gear;
• a spring operably mounted to the housing and adapted to generate the torsional biasing force, the spring having a first end constructed to engage the flanged bracket and having a second end;
• a gear arrangement engaging the second end and the ring gear that is configured to change a position of the second end with mechanical advantage to adjust a tension of the spring;
• a handle for operating the gear arrangement;
• and
• a clutch operably attached to the gear arrangement and the handle that is constructed to lock when a biasing force is received from the spring and the back support, but configured to release and allow movement of the handle and the gear arrangement to adjust a tension of the spring when the handle is manipulated.

A furniture unit comprising:

• a first structural component;
• a second structural component movably attached to the first structural component;
• and
• a force adjusting device including a biasing member biasing the second structural component relative to the first structural component, an adjuster configured to adjust the biasing member, and a clutch;
• the force adjusting device including a force multiplier to reduce a force required to move the adjuster, and the clutch being configured to release the adjuster to permit adjustment when operated by an operator, but that locks the biasing member in a selected position when the adjuster is not being operated by an operator.