Howdon Power Transmission LtdHowdon Power Transmission

Paganhill Lane, Cainscross, Stroud, United Kingdom

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Torque Limiters Manufacturer | Howdon Power Transmission Ltd

Registered in England: Company No: 1316321 VAT No: GB 298 4367 03

Registered Office: Chargrove House, Shurdington Road, Shurdington, Cheltenham, Glos GL51 4GA

Torque Limiters Manufacturer | Howdon Power Transmission Ltd Howdon Power's Blog Page October Blog

Wedgepin vs shearpin: the crucial advantages that save you time and money

In last month’s blog, we looked at how Howdon are doing their bit for the environment by fitting solar panels, LED lighting and more efficient heating.

Made exclusively by Howdon Power Transmission since 1977, our trademarked Wedgepin torque limiter is a simple fix for the disadvantages of traditional shearpin design. Since then, it’s been used by businesses around the world to protect complex and costly equipment, and limit the associated downtime and expense of repair.

This month, we look at the advantages of the Wedgepin over the traditional shearpin.

Torque limiters: the simple way to prevent expensive downtime and repair

A torque limiter  ・also called an overload clutch is a simple device that protects mechanical equipment against damage.

Picture the scene: in a factory in deepest England, a widget-making machine is churning away happily making widgets. While it痴 an efficient piece of kit, the widget-making machine isn稚 fitted with a torque limiter.

Suddenly, the widget-making factory experiences a power surge, which causes a mechanical overload on the poor widget-making machine. The overload damages the machine, and production grinds to a halt. Cue expensive repairs, lost production time and disappointed customers.

If only the factory manager had thought to install torque limiters on his equipment. All that lost time  ・and money  ・could致e been avoided for a small upfront investment.

Types of torque limiter

There are two main types of torque limiter  ・mechanical and electrical. While some engineers consider manual, mechanical torque limiters to be outdated, they池e the most efficient way to reduce damage caused by crash jams and stops (think back to our widget-making machine). And because they instantly disconnect the drive from driven parts, they ensure operator safety and prevent damage in the case of sudden mechanical breakage.

Electronic torque limiters struggle to match this performance because overload needs to be passed back through the process, gearbox and driver before it can be sensed ・and only then can the electronic overload clutch apply a brake torque, or disconnect to stop the equipment.

There are different types of mechanical torque limiters  ・each with its own advantages and disadvantages. The main types are shear pin, ball detent, friction slip clutch, hydraulic clutch, and magnetic clutch. Shear pin overload clutches work like a mechanical fuse or trip switch to uncouple the load completely, while others use slippage to limit torque.

The Wedgepin torque limiter: a simple solution to an age-old problem

Howdon Power Transmission invented the Wedgepin torque limiter back in 1977, as a simple solution to overcome the disadvantages of the traditional shearpin  ・and it痴 been sold around the world ever since.

Its clever design makes the Wedgepin the ultimate overload protection device in slow running/high torque applications. (High speed applications where overloads occur frequently are more suited to ball detent clutches.)

The Wedgepin is failsafe under all conditions, and isn稚 affected by changes in temperature or humidity.

Its wedge construction provides maximum rigidity with no backlash ・making it ideal for indexing or reversing drives.

Simple radial loading at the flange edge is easy to reach, meaning the drive can be reset in minutes.

Multiple pins on high torque drives offers accurate load sharing capacity with a small footprint.

The Wedgepin doesn稚 allow unauthorised fitting of unknown shear pins such as nails or screws, which improves operator safety.

The Wedgepin is clamped in the slots radially ・which prevents fretting, and removes load sharing uncertainty, unlike traditional shearpins.

Shear necks are standardised and colour coded, so customers can easily reorder the model they need.

It doesn稚 rely on mechanism lubrication to be released.

The Wedgepin is easier to fit than the traditional shear pin, which needs to fit through the face of the flanges in a sleeve, making it harder to reach and remove the broken pieces.  

By investing in torque limiters for his equipment, the widget-making factory owner could effectively and affordably have prevented damage to his machinery,  and the associated downtime and costs.  

To find out more about the Wedgepin and other Howdon engineering solutions, call our sales team on 01453 750814, email, or visit