| 摘要 |
<p>On a shaft fitting member, a plurality of hooked shaft guide pieces of an appropriately resilient plastic material are disposed alternately along the opposite edges of the shaft fitting member confrontingly at staggered positions. In the space formed inside the shaft guide pieces thus confrontingly disposed, there is inserted a plastic shaft having a raised strip with parallel edge faces each adapted to keep sliding contact with the horizontal face of the hooks of the shaft guide pieces on its side. One edge face of said raised strip is provided with one sawtooth projection permitting the shaft to slide only in the push direction and a plurality of trapezoidal projections permitting the shaft to be locked at any of as many selected positions. Owing to the construction described above, the shaft is permitted to slide in the push direction but, in its motion in the pull direction, it is allowed to slide over a fixed limited distance and is kept from being completely withdrawn from the guide pieces because of the sawtooth projection. The trapezoidal projections serve the purpose of locking the shaft's sliding motion at any of the selected positions which are determined by the location of the said trapezoidal projections.</p> |
