A lifter is provided with operating levers, which, against driving forces of actuators that switch the ratchet pawls to unengaged orientations, switch the ratchet pawls to engaged orientations of being engaged with ratchet gears, is provided with a link mechanism, which, when a workpiece support base is being lowered by collapsing motions of a pair of right and left crosslink mechanisms supporting the workpiece support base and a difference arises in movement amounts of movable support shafts at lower end sides of the respective crosslink mechanisms, converts the movement amount difference to an operating force of the operating lever at the larger movement amount side, and is such that by the operating lever at one side being driven by the link mechanism, the operating lever switches the ratchet pawl at the larger movement amount side to the engaged orientation.

The present invention is an improved apparatus and method for forming a retractable tower or column. The present invention includes pointed hooks wherein the hooks are attached to each section of a section chain, one in a horizontal direction and one in an off-set manner. The section chains are placed on a take up mechanism in an operable position and then raised utilizing a motor. As the section chains are raised, they are guided by a guide tower, rollers, shims, and gear racks into a position whereby hooks from adjacent sections of the section chains form coupled engagements. The coupled engagement of the hooks of the sections of each adjacent section chains thereby form the column.

The present invention is an improved apparatus and method for forming a retractable tower or column. The present invention includes pointed hooks wherein the hooks are attached to each section of a section chain, one in a horizontal direction and one in an off-set manner. The section chains are placed on a take up mechanism in an operable position and then raised utilizing a motor. As the section chains are raised, they are guided by a guide tower, rollers, shims, and gear racks into a position whereby hooks from adjacent sections of the section chains form coupled engagements. The coupled engagement of the hooks of the sections of each adjacent section chains thereby form the column.

Provided is an interlocking chain-type forward and backward actuating device, the device being configured so that an increase in the number of parts is minimized, an increase in the size of the device is avoided, the amount of scattering of lubricating oil to the outside of the device is reduced, the wear of connection pins is reduced, the breakage of the connection pins is avoided, and the striking noise and vibration of the chains occurring during the reception of the chains are reduced. Chain guide plates are respectively provided on both sides of a pair of interlocking chains in the chain width direction. Chain locus restriction members having chain locus restriction faces in contact with rigid chain portions, which are made rigid by engaging and integrating the pair of interlocking chains with each other, are disposed so as to be adjacent to the rigid chain portions.

Provided is a raising and lowering apparatus which enables achievement of a design that enables a reduction in height of a stage in a raising and lowering direction while reducing the buckling of a push chain. The raising and lowering apparatus includes a push chain (10), a stage (12), a guide (14), and a sprocket (16). The push chain has a first straight rod part (10A) that extends along a first direction (D1), a second straight rod part (10B) that extends along a second direction (D2), and a first bent part (10C) that is provided between the first straight rod part and the second straight rod part. The stage is formed on the first straight rod part and is raised and lowered along the first direction. The sprocket engages with a push chain on a side closer to the second straight rod part than to the first bent part.