Abstract: A corridor spanned or suspended between horizontal support members such as girder members in structures such as those of buildings, ships, etc. so that operators can walk or carry out operations on the corridor.The corridor comprises a main corridor and a sub-corridor, connected to the main corridor to adjust the length of the corridor.This corridor can be easily incorporated in and moved from structures to be built, easily transported and housed in narrow spaces and mounted on different length of places by one unit of the corridor.

Abstract: A locking device is disclosed for locking a brace having an opening therethrough, which comprises a bar member adapted to extend through the opening having a groove defined therein at a spaced location from a front end of the bar member which is insertable into the brace opening. A stopping piece is rotatably mounted in the groove having a hook or abutment portion at the front end thereof engageable with a front side of the groove to limit a rotation of the stopping piece in one direction, and engaging stop and projection portions at a rear end of the stopping piece. A vertical surface is defined on the engaging stop portion for abutting the brace, to lock the brace on the bar member. The projecting portion is provided to prevent an overrotation of the stopping piece.

Abstract: One or more pantographs are connected below a working base and are connected with a main cylinder horizontal or inclined in respect to a supporting base so as to be driven to be extended or contracted. One or more comparatively short auxiliary telescopic cylinders are erected below the working base. During the initial phase of upward movement of the working base the auxiliary cylinders will act directly to push up the working base and, when it has been elevated to a predetermined height, the pushing force is shifted to the main cylinder so that the working base may be further elevated through the pantographs.When the working base is lowered, the pantographs and main cylinder will be compactly folded.