| 摘要 |
<p>A variable length support column (100) for mounting a seat on a base to form a variable height seat comprises an elongate tube (121) and a rod (112) longitudinally slideable together or apart to shorten or to extend the column;
a spring (127) acting indirectly between the first tube (121) and the rod (112) to tend to lengthen the column;a ring of steel balls (124) mounted in bores in tube (121) displaceable to engage against grooves (114) in the rod - (112) at any one of different extensions of the column to lock the column at said extension;
and a release tube (125) axially shiftable to release the balls (124) into a groove (126) in the release tube to unlock the column.</p> |
