Hi-Load Screw Jack with Wing Nut

Hi-Load Screw Jack with Wing Nut is the heavy-duty adjustable jack that carries formwork beams in falsework towers under slab and deck formwork. The U-head or fork-head top bears directly on the beam, while the adjustable stem fine-tunes the shoring height. Specify diameter, length, head type, thread, finish and the quantity you need.

Request a quote Contact sales

At a glance

Hi-Load Screw Jack with Wing Nut at a glance.

Head design

U-head and fork-head options load the beam

The U-head has a rectangular bearing surface that holds the beam centred; the fork head grips both sides of the beam so the jack cannot shift sideways under load. Either design sits at the top of the tower frame.

Heavy-duty geometry

Larger stem for greater capacity towers

Larger diameter stem (48.3, 60.3 mm) and longer adjustment range (30–120 in, 760 mm–3 m) than the base jack, with heavier cast or forged wing nut.

System role

Head of falsework towers, support for beams

The hi-load jack sits at the top of a falsework tower frame, directly under a formwork beam. Its adjustable height sets the soffit of the deck during casting, then is lowered to strike the formwork.

Also known as

Hi-Load Screw Jacks are U-head jacks or shoring jacks in the US and U-head jacks in the UK; in other languages they are vérin fourche (French) and Kopfspindel or Schwerlastspindel (German).

United States: heavy duty screw jackshoring jacku head jack
UK & Ireland: U-head jack
Français: fourche à vérinvérin fourche
Deutsch: KopfspindelSchwerlastspindel

Trade names for the whole range

How it works

Position under the beam and adjust the height

Position the jack on the shoring frame below the formwork beam. Thread the wing nut onto the stem and turn to raise the jack until the head contacts the beam. Continue turning to lift the beam to the required soffit level. The U-head or fork head keeps the beam centred on the jack as the stem rises.

Screw Jack with Base Plate & Wing Nut
Choose the base jack for the foot of a scaffold: it stands each standard on a square base plate and levels the scaffold on uneven ground.
Hi-Load Screw Jack with Wing Nut This page
Choose the hi-load jack for falsework and shoring towers: its larger stem and U-head or fork head carry the beams under the formwork.

Common applications

Where it is used.

Application

Shoring under flat slab and deck formwork

Flat slabs during casting need shoring towers at intervals across the span. Each tower is topped with a hi-load jack that lifts and holds the formwork deck at the correct level until concrete is cured.

Application

Back-propping under beams and composite decks

After slab casting, back-shores support the new concrete while the primary formwork is removed from below. Hi-load jacks are set under the beam to carry its weight while other work proceeds.

Application

Adjustable height for varying soffit requirements

Different floors sit at different levels within the building. The hi-load jack's adjustment range accommodates these height differences, so each floor's formwork can be set to its required soffit position.

What is a hi-load screw jack called in different regions?

Hi-Load Screw Jack with Wing Nut is a U-head jack, shoring jack or heavy duty screw jack in the US, a U-head jack in the UK and a U head jack in Australia and New Zealand. It is a vérin fourche in French and a Kopfspindel or Schwerlastspindel in German.

What heads can a hi-load screw jack carry?

Hi-Load Screw Jack with Wing Nut can have a base plate, a U-head or a fork head. The U-head or fork head holds a primary beam at the top of a falsework or shoring tower, and the wing nut on the 48.3 or 60.3 mm stem sets the final level.

Scaffolding & Shoring Systems

Part of falsework and shoring-tower systems

Hi-Load Screw Jack with Wing Nut sits at the top of falsework towers, directly under formwork beams. Props and threaded tubes work alongside it to support and adjust the tower height.

Explore scaffolding & shoring systems

Hi-Load Screw Jack with Wing Nut specifications