| 摘要 |
<p>Rotary motion is converted to linear motion by multiple thread sets which cooperate to provide precise control of the amount of rotary motion thus converted. As applied to a precision positioning device for a tool, blade or other object, the thread sets are preferably arranged in a serial and/or telescoped configuration. A relatively simple precision hand tool positioning device is realized by having one thread set arranged in a common direction but reduced pitch relative to the other set. The finiteness of the object positioning is further enhanced by moving it with respect to an inclined plane. A retaining device for gripping the element to be moved is directly associated with a shank having the smaller pitched thread set thereon. The shank is prevented from rotating but allowed to move linearly relative to a housing and the threads thereof engage a spindle which has another set of threads for engaging the housing. A calibrated indicator of the shank position in easily readable format is provided. A split collet for the shank with a spring biased collet clamp and actuator is particularly well-suited for use as a tool chuck especially useful for calibrated craftsman knives. A detent arrangement can be included with the housing.</p> |
