HOWDON SHEARPIN TORQUE LIMITERS

Have you got a Torque Overload problem? Talk to Howdon and let us solve it for you.

Howdon have been involved in the design and manufacture of Torque Limiters for over thirty years. Overload clutches and Torque Sensors are often expensive and complicated to use, so to answer the demand for simple solutions for torque overload we invented the revolutionary Wedgegard Shearpin Torque Limiter.

Overcoming the problems associated with conventional round shearpins, a wedge shaped shearpin was developedintroducing a completely new concept for torque limiters. A comprehensive range of overload clutches has been produced using the Wedgegard Shearpin Torque Limiter, and are successfully employed worldwide protecting conveyor drives, sewage and process pumps, road tanker PTO drives, steel and paper mills, marine propulsion, to name a few.

Building upon the Wedgegard Shearpin Torque Limiter, Howdon Power Transmission continues to develop outstanding torque limiters for mechanical drive overload problems met in the increasing demands of todays process plant requiring fail-safe, dependable overload protection.

WHY USE A WEDGEPIN?

  • Wedge construction gives maximum rigidity with no backlash – ideal for indexing or reversing drives.
  • Easy access – drive re-set in minutes with no special tools required (just one Allen key)
  • Clamping screws give positive axial location so the shear neck cannot be displaced from the correct position between flanges.
  • Equal load sharing with multiple pins on high torque drive gives a very high capacity within compact dimensions.
  • Shear necks are standardised and coded, giving safe, tamper proof repeatability and spares economy.
  • ‘Fail safe’ under all conditions, the Wedgegard is not effected by changes in temperature or humidity. The ability to release is not dependent on mechanism lubrication.
  • SPACERS

Mechanical Power Take Off systems on bulk transport vehicles used to drive pumps, blowers and compressors they are subject to foreign body intrusion, product gell or clogging, together with overspeed. Damage is always expensive in repair costs and ‘off the road’ time.

 

CHAIN AND PULLEY

Wedgegard™ Type S model has been designed to protect high torque drives on En Masse and Floor Conveyors, Bulk handling, Food Process Plant and Waste Treatment.

Developed to be unaffected by changes in temperature or humidity the Type S model is not dependent on large spring forces and static friction problems associated with clutch mechanisms and slip clutches.

The Type S models are ideal for fitting to slow / high torque shafts eliminating the problems of delayed reaction in electrical overload devices.

 

FLEXIBLE COUPLINGS

Shaft to shaft drives for extruders, crushers, pulverizers, conveyors, mixers and pumps demand robust overload couplings.

A range of Wedgegard non-lubricated flexible couplings have been designed to combine drive safety while accepting parallel, angular and axial misalignment together with considerable torsional flexibility complete with overload.

Our engineers have built a reputation on meeting the precise specification so, if the standard range does not suit, please contact us to discuss your requirements.

 

GEAR COUPLINGS

Shaft to shaft high torque drives used in bulk handling systems for coal, cement, sugar, rubber and steel mills require reliable protection for expensive equipment. Using gear type couplings Howdon have designed a complete range of Wedgegard spacers that sandwich between coupling flanges.

Gear type couplings are designed and manufactured to AGMA standards. When combined with the Wedgegard spacer effective drive protection with accessibility is provided in all operating conditions.

 

CHAIN COUPLINGS

The chain coupling, comprising two single sprockets connected by a lengh of Duplex chain, provides a torsionally stiff drive capable of accommodating angular and parallel misalignment with the advantage of easy installation.

Howdon offer a range of chain couplings combined with the type S Wedgegard Torque Limiters to ensure drive protection in arduous working conditions such as kiln drives, feeders and fans.

 

RIGID COUPLINGS

Where drive systems cannot accept torsional, angular or parallel misalignment, rigid shaft couplings have to be employed. However, such drives are often subjected to shock loading which cause severe damage to the drive train.

Howdon offer the Wedgegard Spacer Torque Limiter to provide effective protection with free running upon release and re-phasing on reset.

 

PHASING HUB

Howdon has developed a range of simple phasing hubs using conical screws to give a wedging action to grip the platewheel or gear and allow 360 degree adjustment.

In this free condition time is saved threading chain through complex machine layouts. When the drive is set the conical screws are tightened to lock giving a positive no slip drive.

 

TEST RIGS

The heart of the Wedgegard products is the Wedgepin

We have invested significantly in custom built static and dynamic test rigs to ensure that the Wedgepins break at their ratedtorque and within tolerance. This gives customers confidence in Howdon Wedgegard products.

Different batches of the same grade material vary in tensile strength within the grade’s band. Brass grade CW614N (CZ121) for example has a tensile strength band of 360 – 500 mPa. This means that if not tested each batch of Wedgepins could have large variations in breaking/shear torque. Our test department tests both statically and dynamically to take into account the differing material tensile strength, determining the correct Wedgepin neck diameters required, this therefore ensures continuity of breaking torque between batches. We have full tracebility of the materials used in each batch of Wedgepins to ensure this happens.

The dynamic test rig has a disc brake and pnumatically actuated thruster which is pulsed to simulate loading on the Wedgepins. Both braking force and pulse frequency can be adjusted to simulate peak and intermittent loading, determining the fatigue life of the pins. This is something unique to Howdon and demonstrates our commitment to continuous improvement and new developments.

Howdon is committed to testing the materials we use, combined with using state of the art 3D CAD software and CNC manufacturing, ensures that our Wedgepins are made to the highest standards.

 

CONTACT DETAILS

Tel:  +44(0)1453 750814

Fax: +44(0)1453 765320

Email: sales@howdon.co.uk

Web:   www.howdon.co.uk

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