An upright support bar includes a mount disposed at the pivotal joint between an outer tube and an inner tube, a button pivoted to the mount and providing an actuation end, a finger grip and a latching portion so arranged that when the actuation end is biased downward, the latching portion is engaged in one of a series of holes of the inner tube, and a sliding block with a locking piece mounted on the mount movable relative to the mount between a first position where the locking piece is abutted against the finger grip to lock the button and a second position where the locking piece is released from the finger grip to unlock the button.

An upright support bar includes a mount disposed at the pivotal joint between an outer tube and an inner tube, a button pivoted to the mount and providing an actuation end, a finger grip and a latching portion so arranged that when the actuation end is biased downward, the latching portion is engaged in one of a series of holes of the inner tube, and a sliding block with a locking piece mounted on the mount movable relative to the mount between a first position where the locking piece is abutted against the finger grip to lock the button and a second position where the locking piece is released from the finger grip to unlock the button.

A hold open rod may include: an inner member; an outer member configured to have the inner member slide in and out of the outer member; a locking mechanism including a portion attached to the outer member and a portion attached to the inner member; a locking plug configured to move axially along an axis of the inner, outer members; a locking dog configured to move radially between a locking position and an unlocking position and a release cable operatively connected to the locking plug and configured to move the locking plug to the unlocking position. A method of actuating a lock mechanism on a hold open rod may also be provided.

A device for forming/stripping props for castings of concrete floor slabs, which comprises, along its axis of extension, in the following order:

a first plate, which is annular and fixed with respect to the axis of extension, and which has a plurality of first protrusions which are directed toward a second plate that can rotate and/or translate on a plane that is perpendicular to the axis of extension and is substantially parallel to the first plate, and plurality of second protrusions which are directed toward the first plate, the second plate having a plurality of third protrusions which are directed toward a third plate, the third plate being annular and fixed with respect to the axis of extension and being substantially parallel to the first plate, and having a plurality of fourth protrusions which are directed toward the second plate.