クロール型階段昇降機の開発

Abstract

The aim of this project is to supply a new, cost-effective stair lift for wheelchair users. For this purpose, a new mechanism, known as "crawltype," has been developed. This system is composed of three parts: traction guides, drive guides, and a hoist carrier. The former two guides are attached to a wall. The traction guide is constructed by a pair of parallel pipes, and the drive guide is set between the traction guides. The hoist carrier is attached to the traction guides by two rollers and can slide on the traction guides. The hoist carrier has one rotating disk driven by an electric motor. On the latter's rim, some free-rotating rollers are mounted, separated by equal degrees along the normal direction of the disk. The disk is set on the hoist carrier at 15 degrees along the line perpendicular to the slope of staircase, parallel to the wall surface of the staircase. The drive guide has been designed for the uniform rotating velocity of the roller attached to the disk to be converted to uniform straight velocity along the traction guide. The resulting drive guide line has a complicated three-dimensional shape. The roller follows on the drive guide by disk rotation. In the case of either straight stairs or spiral stairs, the number of rollers on the disk is four. However, in the case of half-turn stairs, the number of rollers on the disk is five, thereby reducing the number of varieties of the drive guides. This mechanism has many advantages over conventional ones: (1) The traction guide and the drive guide are not mechanical parts, therefore they do not need lubricating oil. This does not soil the clothes of the user on the staircase; (2) drive guides are set closer to the wall, and are set on the inner side from the surface formed by a pair of traction guides. They are composed of cylindrical pipes without sharp edges. This means that they do not hurt children by their indiscreet behavior; (3) the shape of the drive guide is complicated however each drive guide is the same shape. This means that manufacturing cost is inexpensive; and (4) the mechanism is safe. The disk is driven by an electric motor via a pair of worm gears. When the electrical power is cut accidentally, the disk holds its own position. Furthermore, the disk is set at 15 degrees toward the wall, therefore a held disk interferes with the drive guide. By virtue of this structure, there is little danger of the hoist carrier sliding down along the traction guides.