Device for adjusting the height of desktop, chair or similar

Apparatus for adjusting the height of an article, such as a table, chair or the like, comprising:

• a base;
• at least one substantially vertical guide tube mounted on said base;
• slide means connected to an article whose height is to be adjusted, said slide means being movably mounted within said guide tube;
• locking means connected to said slide means for locking said slide means at a selected position within said guide tube to thereby lock the article at a desired height, said locking means including at least one first wedge member mounted on said slide means having a wedge surface which defines a first space with said guide tube which diminishes in size in the upward direction and at least one corresponding first locking member positioned in said first space, and at least one second wedge member mounted on said slide means having a wedge surface which defines a second space with said guide tube which diminishes in size in the downward direction and at least one corresponding second locking member positioned in said second space, said at least one first wedge and locking members constituting means for preventing downward movement of said slide means and said at least one second wedge and locking members constituting means for preventing upward movement of said slide means;
• releasing means for moving at least one of said first and second locking members in a substantially vertical direction for locking or releasing said slide means with respect to said guide tube.