| 摘要 |
An extensible and retractable rod comprising an outer tubular section and an inner section of substantially constant outside diameter telescopically received in the outer section for extension and retraction relative thereto. The outer section has a first internal shoulder spaced from but relatively close to one end of the section, and a second internal shoulder spaced substantially farther away from said one end, said outer section being dimensioned to have a first inside diameter between said one end of the section and the first shoulder, a second inside diameter greater than the first between the first and second shoulders, and a third inside diameter greater than the second between the second shoulder and the other end of the section. The first inside diameter of the outer section is dimensioned for a relatively close clearance fit between the sections, and the second inside diameter of the outer section is dimensioned for a relatively loose clearance fit between the sections. The inner section has a stop at one end thereof engageable with the second shoulder of the outer section for limiting extension of the two sections relative to one another. The inner section may be releasably locked in an extended position relative to the outer section, with the relatively close clearance fit between the sections rigidly holding the sections in generally coaxial alignment.
|
