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.

A vertically movable workpiece support device has a ratchet wheel with a larger diameter than the outer diameter of a driving sprocket wheel and is concentrically attached to an end surface of a boss portion in the driving sprocket wheel. A pair of left and right bearing members are provided side by side, on a side on which the free end side of a drive chain is horizontally extended with respect to the driving sprocket wheel, so as to sandwich a horizontally extending path section of the drive chain. A movable pawl is pivotally supported between the pair of left and right bearing members and engages with the ratchet wheel to block the rotation of the ratchet wheel caused by the movement of the drive chain when the workpiece support base is lowered. An actuator switches the movable pawl to a non-action position with respect to the ratchet wheel.

A vertically movable workpiece support device has a ratchet wheel with a larger diameter than the outer diameter of a driving sprocket wheel and is concentrically attached to an end surface of a boss portion in the driving sprocket wheel. A pair of left and right bearing members are provided side by side, on a side on which the free end side of a drive chain is horizontally extended with respect to the driving sprocket wheel, so as to sandwich a horizontally extending path section of the drive chain. A movable pawl is pivotally supported between the pair of left and right bearing members and engages with the ratchet wheel to block the rotation of the ratchet wheel caused by the movement of the drive chain when the workpiece support base is lowered. An actuator switches the movable pawl to a non-action position with respect to the ratchet wheel.

A vertically movable workpiece support device has a drive chain bendable to only one side which supports a workpiece support base in a vertically linear path section. The drive chain extends from one end portion coupled to the workpiece support base to an intermediate portion engaging with a driving sprocket wheel. A chain guide plate which sandwiches, with the driving sprocket wheel, a link-to-link roller of the drive chain is arranged on an outer side of the driving sprocket wheel. A mark is displayed, on the side surface of the chain guide plate, in a position separated a certain distance outward from a turning path of links in the drive chain, and an opening portion for visually checking the mark is provided in a side wall which pivotally supports the driving sprocket wheel.

A vertically movable workpiece support device has a drive chain bendable to only one side which supports a workpiece support base in a vertically linear path section. The drive chain extends from one end portion coupled to the workpiece support base to an intermediate portion engaging with a driving sprocket wheel. A chain guide plate which sandwiches, with the driving sprocket wheel, a link-to-link roller of the drive chain is arranged on an outer side of the driving sprocket wheel. A mark is displayed, on the side surface of the chain guide plate, in a position separated a certain distance outward from a turning path of links in the drive chain, and an opening portion for visually checking the mark is provided in a side wall which pivotally supports the driving sprocket wheel.

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.

An engagement chain has two chain members. Each of the chain members includes link plates, each of which has two pin holes, and coupling pins. The two pin holes are aligned in the advancing/retreating direction and are sized differently from each other. Each of the coupling pins of each chain member is tightly received in the smaller pin hole of the two pin holes of one of any adjacent two of the link plates in the advancing/retreating direction and is loosely received in the larger pin hole of the two pin holes of the other one of the two adjacent link plates. In a state in which the chain members are integrated with each other, any two of the coupling pins that are opposed to each other are in the same received states in the corresponding pin holes.

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.