Cuplock – U-Head Jack

(Adjustable Head Support) EN74 / BS1139

Product Overview

U-Head Jack is an adjustable top-support element that can be found in shoring towers, slab formwork, and heavy-duty scaffolding structures. With a firm seat for beams, walers, or decking panels, the U-Head Jack allows local height adjustment, ensuring precise load transfer from the supported element to the main scaffold standards.

The U-Head Jack maintained stability under high axial loads thanks to its solid, high-strength S355 steel construction, forged U-section head, and ACME-threaded spindle. Furthermore, it meets all the requirements of Aramco GI 8.001, SABIC §9.4, BS EN 74, and BS EN 12811; thus, it can be used without any safety concerns in oil and gas, industrial, and infrastructure sectors.

Key Features & Advantages

  • High Load Capacity: Up to 45 kN safe working load (tested per BS EN 12811).
  • Precision Leveling: 300 mm acceptable adjustment range for accurate shuttering alignment.
  • Forged U-Section Head: 160 × 120 mm seat for uniform beam contact.
  • Corrosion Protection: Hot-dip galvanized ≥ 85 µm (ISO 1461).
  • Smooth Thread Operation: ACME rolled threads prevent jamming under load.
  • Interchangeable Design: Fits , and most modular systems.

Technical Specifications

  • Material: S355 JR (EN 10025)
  • Thread Type: ACME / Trapezoidal rolled thread
  • Head Plate: U-section 160 × 120 × 60 × 6 mm
  • Spindle Diameter: 36 mm
  • Welding: CO₂ / MIG per ISO 3834-2
  • Finish: Hot-Dip Galvanized (ISO 1461)

Dimensional Data

Item Code Description Spindle Length (mm) Adjustment (mm) Head Size (mm) Weight (kg)
SP-UH-0450 U-Head Jack 450 mm 450 300 160 × 120 × 60 × 6 4.1
SP-UH-0600 U-Head Jack 600 mm 600 350 160 × 120 × 60 × 6 4.6
SP-UH-0750 U-Head Jack 750 mm 750 400 160 × 120 × 60 × 6 5.2
SP-UH-0900 U-Head Jack 900 mm 900 450 160 × 120 × 60 × 6 5.8

Structural Performance

Parameter Unit Result Reference
Safe Working Load (SWL) kN 45 BS EN 12811 Annex D
Ultimate Load kN 68 BS EN 12811
Deflection at SWL mm ≤ 3.0 BS EN 12811
Head Seat Bending Strength kN·m 6.0 Internal Test SPAR-QA-UHJ/2024
Safety Factor – 1.5 Aramco GI 8.001
Thread Tolerance mm ± 0.5 BS EN 74
Coating Thickness µm ≥ 85 ISO 1461

Compliance & Certifications

Standard / Client Clause Description
Aramco GI 8.001 Sec. 6.1 Shoring and formwork safety criteria for adjustable supports.
SABIC §9.4 Table 3 Component inspection and re-testing intervals.
BS EN 74 Clause 4 Thread and forging mechanical performance.
BS EN 12811 Annex D Load testing and deflection control.
ISO 3834-2 Clause 8 Welding quality management.
ISO 1461 Clause 6 Galvanizing thickness and adhesion.

All U-Head Jacks are tested and certified through Arabian ALTRAD SPAR’s QA Laboratory and validated by third-party inspectors for Aramco and SABIC projects.

Quality Assurance (QA / QC)

Inspection and Testing Steps

  • Raw material verification (MTC review per EN 10219).
  • Thread pitch and depth inspection with precision gauges.
  • Weld visual and MT inspection on head-spindle joint (10 % sample).
  • Coating thickness check (≥ 85 µm) with magnetic gauge.
  • Proof load testing under axial compression (≥ 45 kN).
  • Final marking and documentation before dispatch.

QA/QC Verification Summary

Stage Inspection Method Acceptance Criteria Frequency
Material Check MTC Verification EN 10219 / S355 JR Each Batch
Thread Inspection Pitch Gauge ± 0.5 mm 100 %
Head Weld Test Visual + MT No Cracks / Full Fusion 10 %
Coating Check Elcometer Gauge ≥ 85 µm Each Lot
Load Test Hydraulic Frame ≥ 45 kN SWL Quarterly
Marking Visual Batch + Heat No. 100 %

Identification & Traceability

Each U-Head Jack is clearly stamped with:

  • “ALTRAD SPAR– U-HEAD JACK – [Length] – [Batch No.] – [Heat No.] – [Year].”
  • Inspector stamp and QA approval code.
  • Optional QR label for digital inventory control via ALTRAD SPARERP system.

Applications

  • Shoring and formwork systems for concrete structures
  • Beam and slab support scaffolds
  • Bridge deck and tank formwork platforms
  • Industrial and infrastructure maintenance scaffolds
  • Temporary works in oil & gas facilities

Maintenance & Inspection

Item Frequency Method
Visual check Before each use Inspect threads and weld joints for damage
Lubrication Monthly Apply anti-seize compound on threads
Galvanizing test Every 3 years Check ≥ 85 µm coating
Proof load retest Every 5 years Verify SWL ≥ 45 kN

Marking & Identification

Each Ledger is permanently stamped with:

  • “ALTRAD SPAR– LEDGER – [Length] – [Batch No.] – [Heat No.] – [Year]”
  • QA inspection mark and batch traceability reference.
  • Optionally available with QR/barcode labels for asset tracking in ERP systems.

Typical Applications

  • Industrial access scaffolds
  • Tank and vessel scaffolding
  • Bridge decks and suspended platforms
  • Formwork, bracing, and shoring grids
  • Maintenance structures in refineries and petrochemical plants

Maintenance & Inspection Guidelines

Item Frequency Method
Visual inspection before issue Every hire cycle Check blade ends, tube dents, and corrosion
Dimensional recheck Annual Verify length and blade seating
Proof load retest Every 5 years Hydraulic load validation as per BS EN 12811