Non-binding cantilevered table lifting device

A vertically adjustable work surface comprising:

• a) a top;
• b) two vertically telescoping leg assemblies supporting said top, each comprising:
• i) a vertically elongated inner member having an upper end attached to the underside of said top and a lower end opposite to said upper end;
• ii) an outer tubular member having walls which enclose an interior space in which said inner member moves vertically and having an open upper end which receives said inner member and a lower end opposite said upper end;
• iii) first rolling bearing means attached to the rear of the lower end of said inner member and urged into rolling contact against an inner wall of said outer tubular member, for supporting said inner member and preventing sliding contact between said lower end of said inner member and said outer tubular member under loading of said top;
• iv) a rack attached to said inner member running in the direction of a longitudinal axis from the upper end to the lower end of said inner member;
• v) a drive shaft rotatably supported on one or more of said walls of said outer tubular member;
• vi) a drive pinion concentrically mounted to said drive shaft and engaging said rack;
• vii) second rolling bearing means attached to said outer tubular member and running against a surface of said inner member, for limiting the maximum depth of engagement of said drive pinion into said rack and preventing binding and excess friction of the pinion and rack;
• c) a horizontal beam rigidly attached to said leg assemblies adjacent to said drive shafts;
• d) drive means for rotating said drive pinions mounted to said horizontal beam between said leg assemblies, said drive means rotatably connected to said drive shafts;
• and
• e) support means attached to said outer tubular members for rigidly supporting said telescoping leg assemblies vertically.