| 摘要 |
PROBLEM TO BE SOLVED: To provide a device for height adjustment used for revolving chairs each with a returning function which moves the revolving chair back to the normal position automatically even when the revolving chair is turned around. SOLUTION: This device for height adjustment used for revolving chairs each with a returning function is provided with a spindle (10), which has a member (20) for a sleeve and is inserted into an outer cylinder (50), a member (30) for a first cam that drives the spindle placed between the outer cylinder and the sleeve in a rotating direction and a direction of a shaft, a member (40) for a second cam. A surface where the member for the first cam contacts with the member for the second cam is inclined and is formed in a manner that two cams match together. A spring (60) is placed under the member for the second cam. When the spindle (10) starts rotating, the inclined surface of the member for the second cam gets separated from the inclined surface of the member for the first cam and compresses the spring (60). As a result, the rotating power of the spindle (10) is removed, and the inclined surface of the member for the second cam returns to the normal position automatically.
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