History of Mobile Access Towers – Part One

Learning Module: History of Mobile Access Towers – Part One

Introduction

This module explores the early history of mobile access towers and the factors that influenced their development. Understanding these origins provides context for the equipment used across construction and facilities management today, including the evolution that led to the Alto Tower.

1. Origins of the Mobile Access Tower

• First Design: The first widely recognised mobile access tower was created in the USA by Wally Johnson in 1947.
• Key features of the design included:
• End frames
• Horizontal and diagonal braces with spring-loaded locking mechanisms
• Hook-on platforms
• Stairs or stairladders
• Adjustable legs
• Spigots for connecting multiple frames

Diagram 1: Extract from Wally Johnson’s 1947 patented application for a mobile access tower

Limitations of the Early Design

The 1947 tower was missing several components that are now standard or common in modern towers:

• Wheels or mobility features
• Guardrails and stair handrails
• Trap platforms or gates to close accessway gaps in working platforms
• Regularly spaced horizontal rungs in end frames to support platforms and guardrails
• Toe boards
• Secure locking mechanisms for spigots
• Any form of external stabilisation

Diagram 2: Generic modern aluminium stair tower for comparison

Although less sophisticated than modern designs, the original basic structure is clearly recognisable in today’s towers.

2. Introduction of Aluminium Towers in the UK

• Adoption in the USA: Aluminium towers were quickly taken up in aerospace and construction.
• Initial resistance in the UK:
• Aluminium was more expensive than steel or timber.
• It was a relatively new material in construction.
• Wood and steel products were already well established.

Why UK contractors began importing towers

• Steel-based systems were heavy and cumbersome.
• Skilled labour was becoming increasingly scarce and expensive.
• Aluminium towers offered lighter, modular alternatives and the opportunity to speed up work.

3. Drivers of Change in the 1960s and 1970s

Several external factors accelerated the adoption of aluminium towers in the UK:

1. Workplace safety: The Health & Safety at Work Act 1974 increased focus on preventing falls from height.
2. Scaffolding regulation: Only trained scaffolders were permitted to erect scaffolds above 5m, creating a need for safe temporary access below this height.
3. Labour shortages: Contractors sought labour-saving equipment to reduce reliance on skilled workers.
4. Growth of the hire and rental industry: Expensive equipment, such as aluminium towers, became more accessible to contractors through hire services.

Summary

• The first mobile access tower was patented in the USA in 1947.
• Early designs lacked many safety and mobility features now considered essential.
• Aluminium towers spread to the UK gradually, facing resistance due to cost and unfamiliarity.
• By the 1970s, regulatory changes, labour shortages, and the rise of the hire industry had accelerated adoption.

Learning Point: The development of aluminium towers demonstrates how innovation, regulation, and industry pressures combine to create safer and more efficient workplace equipment.