An extendable and retractable column which is formed from at least three linked sections. The linked sections include a plurality of individual sections linked end to end. As the linked sections are extended, each of the individual sections engage adjacent individual sections to form a column. As the linked sections are retracted, each of the individual sections disengage from the adjacent individual sections and the column may be retracted for compact storage.

An extendable and retractable column which is formed from at least three linked sections. The linked sections include a plurality of individual sections linked end to end. As the linked sections are extended, each of the individual sections engage adjacent individual sections to form a column. As the linked sections are retracted, each of the individual sections disengage from the adjacent individual sections and the column may be retracted for compact storage.

An extendable and retractable column which is formed from at least three linked sections. The linked sections include a plurality of individual sections linked end to end. As the linked sections are extended, each of the individual sections engage adjacent individual sections to form a column. As the linked sections are retracted, each of the individual sections disengage from the adjacent individual sections and the column may be retracted for compact storage. Methods of forming such an expandable/retractable column are also presented.

A transmission for an adjustable-height platform includes at least one drive shaft, at least one output shaft, at least one first gear wheel configured to transmit a rotational movement of the drive shaft to the output shaft, and at least one second gear wheel configured to drive a hollow second output shaft. The at least one first gear wheel is formed from or includes at least portions formed from plastic.

An extendable and retractable column which is formed from at least three linked sections. The linked sections include a plurality of individual sections linked end to end. As the linked sections are extended, each of the individual sections engage adjacent individual sections to form a column. As the linked sections are retracted, each of the individual sections disengage from the adjacent individual sections and the column may be retracted for compact storage. Methods of forming such an expandable/retractable column are also presented.

An extendable and retractable column which is formed from at least three linked sections. The linked sections include a plurality of individual sections linked end to end. As the linked sections are extended, each of the individual sections engage adjacent individual sections to form a column. As the linked sections are retracted, each of the individual sections disengage from the adjacent individual sections and the column may be retracted for compact storage.

An extendable and retractable column which is formed from at least three linked sections. The linked sections include a plurality of individual sections linked end to end. As the linked sections are extended, each of the individual sections engage adjacent individual sections to form a column. As the linked sections are retracted, each of the individual sections disengage from the adjacent individual sections and the column may be retracted for compact storage.

An extendable and retractable column which is formed from at least three linked sections. The linked sections include a plurality of individual sections linked end to end. As the linked sections are extended, each of the individual sections engage adjacent individual sections to form a column. As the linked sections are retracted, each of the individual sections disengage from the adjacent individual sections and the column may be retracted for compact storage.

An extendable and retractable column which is formed from at least three linked sections. The linked sections include a plurality of individual sections linked end to end. As the linked sections are extended, each of the individual sections of the linked chains engage individual sections of adjacent linked chains to form a column. As the linked sections are retracted, each of the individual sections of the linked chains disengage from the individual section of the adjacent linked sections and the individual linked sections may be rolled up for compact storage.

A linear actuator includes a telescoping sleeve (100). The telescoping sleeve (100) includes an inner sleeve (110), an intermediate sleeve (120) sheathing the inner sleeve (110) and an outer sleeve (130) sheathing the intermediate sleeve (120). A base (200) connected to the intermediate sleeve (120); a motor (300) arranged on the base (200); a reduction worm gear (400) pivoted on the base (200) and driven by the motor; a rotor worm (500) pivoted on the base (200) and engaged with the reduction worm gear (400); a rotor worm gear (800) pivoted on the base (200); a stator worm (700) inserted in the rotor worm gear (800) and connected to the outer sleeve (130); and a stator nut (900) connected to the inner sleeve (110) and engaged with the rotor worm (500) are arranged in the telescoping sleeve (100).