A construction beam head assembly comprising an improved forming system having one or more fixed beam-head prop assemblies each having an upper portion and a lower portion. The upper portion having a screw-jack threaded shaft assembly and a drop-head The lower portion comprising of a prop and a collar The screw-jack threaded shaft assembly having an external diameter and an external threading The screw-jack threaded shaft assembly attaches to the drop-head The upper portion selectively slides into the lower portion The collar having an internal threading and an internal diameter The internal threading of the collar rotateably attaches to the external threading of the screw-jack threaded shaft assembly of the upper portion. The upper portion and the lower portion adjustably attach to one another with the collar and the screw-jack threaded shaft assembly to provide a variable height of the prop assembly.

A locking mechanism for locking an inner tube with an outer tube of an adjustable telescopic push-pull prop assembly is disclosed. The locking mechanism includes a slotted prop nut having a slot and adapted to move in either direction when rotated on the outer tube having threads, a guiding ring adapted to be accommodated in the slot of the slotted prop nut, and a captive grooved pin assembly adapted to be accommodated in the guiding ring for locking and unlocking the inner tube and the outer tube such that the slotted prop nut encases the guiding ring and the captive grooved pin assembly. The positioning of the captive grooved pin assembly is such that it does not hinder the rotation of the slotted prop nut.