Bells, hammers and gongs

Click on any image for an enlargement. (up to 400kB) Back click to return to the text.

Try reloading the page if you are a regular visitor to ensure you see the latest version.

Striking Telavox clocks use the rack and snail strike mechanism common to millions of other clocks of many styles and ages. Though the Telavox is rather unique in having an electric motor to run the entire strike. The Telavox motor also rewinds the small, going spring at the same time as it drives the strike. Most other clocks use weights or springs to lift the rack back up and to lift the hammer(s) so that they fall onto a bell or gongs.

A recent email from a Telavox owner raised the question of unreliability of striking exactly 12 blows at 12 o’clock. Only then did I realise that I had not described or illustrated the Telavox strike here in any detail.

 Here is a general view of the striking side of the Telavox movement. It is not normally seen because it is hidden behind the dial. Here the rack is fully lifted to its rest position. The rack hook is safely tucked under the toe of the rack. The strike is started by the rack hook being lifted by a lever on the other (more visible) side of the movement. When the rack hook lifts the rack falls freely until its toe rests on a particular step of the snail. The heights of the steps on the snail are calculated to provide a fixed number of teeth to be lifted by the gathering pallet. Which also counts the number of blows needed to be struck on that particular hour.

Access to this area is rather difficult on the Telavox. It involves removing the decorative outer bezel, the dial glass, the hands and finally the dial and chapter ring.  The inner sight ring can remain screwed to the case. The outer bezel is a thin, brass pressing which is pushed onto the concealed, inner ring. Removal requires considerable care not to mark or distort the very thin metal of the bezel or cause damage to the fine veneers of the casework. One must also take great care not to break or drop the dial glass. I already had a Telavox clock which was bought cheaply with a broken glass. So I had the perfect opportunity to explore the dial construction without fear of breaking the original, convex glass. I used a 1/2″ (12mm) wood chisel to lift the outer bezel by working all the way around and lifting carefully a little at a time.

Once the fragile glass and bezel are set safely aside the clock hands must also be removed before the dial is free to lift off. The chapter ring rests on the metal dial and may held in place by the inner bezel ring. (depending on the model) The bright colour of the frosted brass dial hidden by the chapter ring may be quite a surprise! Do not start cleaning anything without expert skills! The Telavox chapter rings are usually only printed (or painted) and cleaning will rapidly remove the figures! As will cleaning the dial centre rapidly remove the printed Telavox signature. I have one such clock myself.

 A closer view of the striking mechanism with the rack having fallen to its lowest point at 12 o’clock. When the strike motor runs, a forward facing pin on the gathering pallet lifts the rack back up again one tooth at a time. The rack hook lifts slightly and then engages with each rack tooth ensuring it cannot fall back again.  Finally, when all the rack teeth have been lifted, the rack hook drops below the toe of the rack and the striking stops.

Note the three rubber bushes where the Telavox movement is held in place in the clock case. The screws which pas through these bushes are only accessible once the dial and glass are removed.

The other side of the movement of another Telavox.  Labelled to show the parts involved in the strike release.

 This is a close-up of the four hammers of a Telavox movement striking the hours and half hours on rod gongs. The levers activated by the movement lift two hammers each via two wires. A two-tone pair of simple two note chords is struck consecutively: Known as a “Bim-bam” strike.

The strike silencing plate, operated by a lever underneath the case, lowers onto the gongs but leaves the hammers free to rise and fall. If the hammers were restrained the clock would not strike, the clock would not be rewound and the clock would stop.

Don’t forget that you can click on any picture on this blog to see a larger version.

Back click to return to the blog.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.