摘要 |
An adjustable mechanism including at least two shafts, one of which is hollow, including: a spring attached to a first shaft; the spring having an outer diameter of similar dimensions to the internal diameter of the second shaft, the spring configured such that once force is applied to the spring, its outer diameter is less than the inner diameter of the second shaft; and when force is no longer applied to the spring it is biased to return to its original outer diameter to bear against the inner diameter of the second shaft. |