Prop Screw Rod

A Prop Screw Rod is a fundamental component of a Telescopic Prop or Adjustable Prop,which is a mechanical support strut widely used in construction to provide temporary vertical support for formwork,slabs,beams,and walls during concrete pouring and curing.The screw rod itself is the critical threaded element that enables the prop's height to be easily and precisely adjusted to the required level and to bear significant compressive loads.

Its primary function is to act as a load-bearing actuator,transferring the weight of the fresh concrete and formwork through the prop and onto a stable base below.

Key Features&Design:

Robust Threading:Features heavy-duty,coarse threading(often ACME thread form)designed to handle high compressive forces without stripping or deforming.The threads run along a significant portion of its length.

End Forging:The top end is typically upset forged or welded to form a U-Head or Fork Head.This head cradles and secures the horizontal formwork bearer(e.g.,a wooden beam or U-channel).

Base Connection:The bottom end is often threaded to accept a base plate or a foot plate.This plate distributes the prop's load over a larger area of the ground or floor below,preventing sinking.

High-Strength Material:Manufactured from high-tensile steel to withstand immense crushing loads without buckling.They are typically hot-dip galvanized for corrosion resistance,essential for the harsh and wet conditions of a construction site.

Integration:The screw rod is not used alone.It threads into the outer tube of the telescopic prop.A manually operated collar or a winding handle engages with the threads to facilitate adjustment.

How It Works:The Principle of Telescopic Adjustment

The prop screw rod is the inner,adjustable member of a two-part system:

The screw rod is threaded into the larger-diameter outer sleeve or tube of the prop.

Rotating the adjusting collar(which acts as a large nut)on the outer sleeve causes the inner screw rod to extend or retract linearly.

Extending:Turning the collar in one direction drives the screw rod upward,raising the prop to the desired height and making contact with the formwork above.

Retracting:Turning the collar the opposite direction lowers the screw rod,allowing the prop to be removed after the concrete has cured.

The large diameter and coarse threads provide a powerful mechanical advantage,allowing a single worker to easily adjust the height of a prop supporting several tons.

Common Applications:

Slab Formwork:Providing temporary vertical support for the decking of concrete floor and roof slabs.

Beam Formwork:Supporting the sides and bottom of concrete beam formwork.

Wall Formwork:Bracing and supporting wall formwork systems.

Temporary Shoring:Used in renovation and repair work to temporarily support existing structures.

Staging and Support:Occasionally used outside of concrete work to support staging,heavy equipment,or structural elements during installation.

Advantages:

High Load Capacity:Engineered to safely support extreme compressive loads(often rated from 2 to 6 tons or more per prop).

Easy and Precise Adjustment:Allows for quick and fine-tuned height leveling of the formwork to the exact grade required.

Durability:Built from robust materials to withstand the rigors of construction site use and reuse.

Safety:A critical component in ensuring the stability of formwork,preventing catastrophic collapse during concrete placement.

Installation Overview:

Positioning:The prop is placed on a firm,level base(often a sole plate for additional stability).

Rough Height Setting:The adjusting collar is turned to extend the screw rod to near the required height.

Fine-Tuning:The U-head is positioned under the formwork bearer.The collar is given final turns to ensure the prop is"hard up"against the bearer,taking the load.

Striking(Removal):After the concrete has gained sufficient strength,the collar is turned in the opposite direction to lower the screw rod and release the load,allowing the prop to be removed.