• Who We Are
    About Kelston


    Kelston produce a wide range of screw jacks, gearboxes and linear actuators. We also offer a bespoke design and manufacturing service. We have a modern, purpose-built, 100,000 sq ft factory located on a 10-acre site near Bristol. Find out more
  • What We've Done
    Hydrostatic Gearbox


    Unlike a traditional transmission system, a hydrostatic drive offers a continuous power curve and hence an infinitely variable forward speed control. Johnston's V Range hydrostatic sweeper model features a Kelston gearbox powered by the main truck chassis engine. Find out more
  • Who We Are
    Design Engineers


    Our technical sales and design team are on hand to answer all your questions. Whatever your application - whether you are designing a 2000-tonne shipyard roll press or a precision measurement system to record the movement of car suspension - we have the experience to help. Find out more
  • Who We Are
    Gear Specialists


    We have a sophisticated in-house manufacturing facility producing components for both screw jack customers and our sub-contract partners. Our modern 100,000 sq ft factory houses a wide range of machining, finishing and assembly processes. Find out more
  • What We've Done
    Bespoke Actuators


    An array of six actuators perform linear movement on five different axes. Each actuator is driven independently by its own servo motor drive. The actuators are fitted with positional control switches, which along with the servo motor, integrate with the SPMM control panel. Find out more

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Knowledge Base

Screw Threads & Mechanical Advantage

Screw Threads & Mechanical Advantage

A screw is a mechanical system that converts rotational motion in to linear motion. In other worlds it converts rotational force (torque ) in to a linear force. Here the resultant axial force due to an input torque is calculated from first principles.

Screw Jack Calculation - Power

Screw Jack Calculation - Power

Kelston has created an online System Builder for customers to quickly and easily determine an appropriate screw jack system.

Electromechanical vs. Hydraulics

Electromechanical vs. Hydraulics

Mechanical screw jacks and linear actuators are increasingly becoming the preferred choice of actuation over the equivalent hydraulic or pneumatic systems.

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