Chairs and seats – Bottom or back with means to alter contour – Providing support for lower back region
Reexamination Certificate
1999-04-21
2001-01-30
Nelson, Jr., Milton (Department: 3624)
Chairs and seats
Bottom or back with means to alter contour
Providing support for lower back region
C297S284100
Reexamination Certificate
active
06179384
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to force adjusting devices, and more particularly relates to a force adjusting device that is easily adjustable to vary a biasing force, but that locks after adjustment to maintain an adjusted biasing force. Further, the present invention concerns a chair that incorporates the force adjusting device into an adjustable lumbar support arrangement on a back of the chair.
Force adjusting devices are sometimes used in mechanical assemblies to provide a biasing force to accomplish a desired result. A problem is that where significant biasing force is desired, these mechanisms can become expensive, unacceptably large in size, and unacceptably complex. Complexity can further result in quality and warranty problems. Another problem is that there often are conflicting requirements for such devices. For example, it is desirable to provide an adjusting motion that is easily accomplished, but that provides significant change in biasing force with only a small amount of adjustment effort and motion. Further, when used in retail consumer products, the adjusting motion must preferably operate smoothly and provide a luxurious feel to the user, while using low cost and easily assembled components. It is difficult to simultaneously achieve such a result. Still further, the adjusting motion must be intuitively obvious so that users will know how to adjust the device without having to read an instruction manual, yet the adjusting device must have an aesthetically acceptable appearance and only take up a minimum of space. Also, assembly of the force adjusting device to the component being biased preferably must be easily accomplished with low labor requirements.
Accordingly, a force adjusting device is desired that is reliable, relatively non-complex, solves the aforementioned problems, and has the aforementioned advantages.
SUMMARY OF THE INVENTION
In one aspect of the present invention, a force adjusting device is provided for adjusting a spring-generated biasing force on a movable component relative to a second component. The force adjusting device includes a housing adapted for attachment to the second component and a spring operably mounted to the housing. The spring has a first end adapted to engage the movable component and has a second end. A force multiplier arrangement operably engages the second end and is configured to change a position of the second end with mechanical advantage to adjust a tension of the spring. A handle is provided for operating the force multiplier arrangement, and a clutch is operably attached to the force multiplier arrangement and the handle. The clutch is constructed to lock when a biasing force is received from the spring, but is configured to release and allow movement of the handle and the force multiplier arrangement to adjust a tension of the spring when the handle is manipulated.
In another aspect of the present invention, a force adjusting device includes a housing adapted for attachment to the second component, and a spring operably mounted to the housing. The spring has a first end adapted to engage the movable component and has a second end. A hub engages the second end and is configured to change a position of the second end to adjust a tension of the spring. A handle is provided for rotating the hub. A clutch is operably attached to the hub and the handle. The clutch is constructed to lock when a biasing force is received from the movable component, but is configured to release and allow movement of the handle and the hub to adjust a tension of the spring when the handle is manipulated.
In another aspect of the present invention, a force adjusting device includes a housing adapted for attachment to the second component, and a spring operably mounted to the housing. The housing includes an internal tooth ring gear. The spring has a first end adapted to engage the movable component and has a second end. A gear arrangement engages the second end and the ring gear and is configured to change a position of the second end with mechanical advantage to adjust a tension of the spring. A handle is operably attached to the gear arrangement for operating the gear arrangement. By this arrangement, the handle can be manipulated to operate the gear arrangement to adjust a tension of the spring.
In yet another aspect of the present invention, a chair includes a back frame and a flexible back support operably supported on the back frame. The flexible back support includes a flexible lumbar region and a flanged bracket pivotally connected to the back frame at a back pivot. A force adjusting device is 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 includes a housing adapted for attachment to the back frame, a spring operably mounted to the housing, and a gear arrangement. The housing includes an internal tooth ring gear. The spring has a first end constructed to engage the flanged bracket and has a second end and is adapted to generate the torsional biasing force. The gear arrangement engages the second end and the ring gear, and is configured to change a position of the second end with mechanical advantage to adjust a tension of the spring. A handle is provided for operating the gear arrangement, and a clutch arrangement is operably attached to the gear arrangement and the handle. The clutch is constructed to lock when a biasing force is received from the back support, but is 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.
In still another aspect of the present invention, a furniture unit includes 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 adjuster includes a force multiplier to reduce a force required to move the adjuster. The clutch is configured to release the adjuster to permit adjustment when operated by an operator, but is configured to lock the biasing member in a selected position when an operator is not operating the adjuster.
These and other features, objects, and advantages of the present invention will become apparent to a person of ordinary skill upon reading the following description and claims together with reference to the accompanying drawings.
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DeKraker Larry
Heidmann Kurt R.
Jr. Milton Nelson
Price Heneveld Cooper DeWitt & Litton
Steelcase Development Inc.
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