| 摘要 |
An adjustable height basketball standard includes a lower tube secured to a ground surface. An upper tube engages the lower tube. A raising and lowering mechanism includes a friction element and engages a handle that may be turned by the user. The friction element substantially resists downward movement of the upper tube unless the friction element is overridden through movement of the handle by the user. The friction element may be a wrap spring, a friction cone clutch, brake plates or shoes, or a similar device. In one embodiment, the upper tube includes a series of notches. A drive mechanism includes a drive housing with a gear that engages successive ones of the notches as the drive housing is turned. When the drive housing is turned clockwise, the upper tube raises with respect to the lower tube, and when the drive housing is turned in counter-clockwise, the upper tube lowers with respect to the lower tube. A spring is wrapped around the drive housing. When the handle is not turned, the spring resists counter-clockwise movement of the drive housing. When the handle turns clockwise, the spring turns with the drive housing. When the handle is turned counter-clockwise, the spring initially resists movement of the drive housing in the counter-clockwise direction. However, after the handle turns about 15 degrees, the spring to be momentarily released. A cable may be used rather than gears.
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