Tuesday, January 26, 2010

Whites Relies On SKF Bearings For Bell Hanging

Bell-hanging company Whites of Appleton is continuing to use SKF bearings, as it has been since the 1920s. At full swing, a church bell can exert a force equivalent to four times its own static weight. For this reason, the way it is mounted is crucial - to contain these forces and to deal with the way these bells hang idle in one position for a long time before being oscillated through 380 degrees.

Whites of Appleton manufactures, supplies and installs most bell-related solutions, apart from the bell casting and tuning. It works all over the country and has many high-profile installations on its books, including St Paul's Cathedral, Windsor Castle and Canterbury Cathedral. According to Brian White, a partner in the company: 'The headstock design has changed significantly over the last century, with timber headstocks being replaced by those made from steel and cast iron, but the one thing that has not changed since the 1920s, from our perspective at least, is the use of SKF bearings.

'At the horizontal position of the swing, the bearings will experience a force equivalent to 2.5 times the static weight of the bell. 'At bottom dead-centre, this rises to four times the static weight, so once we know the weight of the bell, we know which bearing to go for,' he finished. Typically, depending on the application requirements, Whites opts for one of seven different variants in SKF's self-aligning ball bearings range, sourced through the Oxford Service Centre of Eriks.

The self-aligning ball bearings - supplied with tapered bores and adapter sleeves for easy mounting and dismounting - are particularly suited to applications that exhibit misalignment either in the shaft housing or bearing seat. They offer extremely low friction, low operating temperatures, reduced vibration levels, lower noise levels and, particularly advantageous for this type of application, low lubrication requirements.

Occasionally an installation may call for SKF Explorer spherical roller bearings made of patented SKF Xbite steel, which has a much longer life due to its increased hardness. Thanks to their ability to accommodate very heavy radial and axial loads in applications prone to misalignment, SKF Explorer spherical roller bearings can last several times longer than their rivals under typical heavy-duty conditions. The bearings are housed in SKF's standard SNL plummer block housings, which are available in a wide variety of sizes to match the bearing specified.

As well as offering a reinforced base, a variety of mounting options, good thermal performance and easy re-lubrication, their versatility means that it is seldom necessary to resort to tailored housings for specific applications. The bearing assembly is completed with Type C felt seals, which suit the semi-external environment and the shaft deflection. The whole assembly is lubricated using a general-purpose industrial bearing grease. Whites uses the bearings and housings to support the bell via two gudgeon pins that extend from either end of the headstock.

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