03/08/2006

Manufacturer's description.

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There follows my (non-literal) translation of the manufacturer's old Danish description of the Telavox movement: This may well be corrected and polished later as I find more precise ways to describe the Telavox movement and its actions.


TELAVOX clock with anchor escapement and electric rewinding and striking:

The clock's construction is based on the principle, that an electric motor, powered by 4.5 Volt torch battery, winds a spring. The spring then provides the power to the escapement for the clock to run. The striking gears (wheels) also provide the transmission of power between the motor and the going spring housing.

It requires only 168 strokes per day to keep the clock fully wound but the clock strikes 180 times in this period.  So the extra 12 strokes, in every 24 hours, provide nearly two extra turns to the going spring. To avoid over-winding the going spring a friction clutch is provided. This ensures the spring is wound only to a pre-arranged tension before the clutch starts to slip. The spring could be wound up to 12 times which provides 12 hours of going power. But the slipping clutch limits the tension to about 8 hours of going power. Which greatly extends the life of the spring by avoiding over-winding. The motor is not self-starting. When the current is connected the motor is started by a sprung arm. Whose movement is controlled by two cams on the minute axle. (or arbor) These cams also control the half and full hour strike.

The clock is provided with an anchor escapement, a rate regulator and a ballistically (sic) suspended, temperature compensated, torsion balance. This system, which is patented in many countries, allows the clock to go regardless of the physical orientation of the movement or its case. In fact it is very insensitive to shocks and shaking. e.g: Under transport. Because the normal balance axle and spiral spring are replaced by a tensioned suspension spring there is nowhere for the oil to thicken. Which would eventually reduce the swing of the balance. Which in turn would affect the going rate (timekeeping) of the clock. So the Telavox keeps very good time, over long periods, compared with normal balance wheel clocks.

The movement plates,  where the movement pivots are housed, is made of a man-made fibre material best known as "Turbonit". This material has been shown to have far superior bearing qualities compared to brass. Such that the oil remains in good condition for far longer than it does in brass plates. Where undesirable chemical reactions can take place. Because "Turbonit" has such excellent insulation qualities the electrically conducting parts can be fixed directly to the movement plates.

Removal of the Telavox movement from its case:

Before the movement can be removed the dial glass and the outer brass bezel must first be removed. The bezel consists of two parts. A thin outer ring (which holds the glass in place) and a fixed inner (sight) ring. The inner ring is screwed firmly to the case and should not be removed. The thin outer ring is pressed down over the inner ring during manufacture and is only held on by friction.

The best tool to lever off the outer ring is a clean, plain wood chisel with a reasonably good cutting edge without damage. The sharpened edge should be gently pressed under the edge of the outer ring to lift it. You should work gently around the ring with the chisel to lift the outer ring off the inner ring. However,  great care is required to avoid catching the sharp edge of the chisel under the inner ring. To do so could cause serious and permanent damage to the case and might easily break the glass.

A wood chisel is broad and flat enough not to damage the case or the edge of the thin shell of the outer ring. Other smaller tools (like screwdrivers) should really be avoided because they could easily and permanently damage the wooden case and bend the edge of the thin outer ring due to localised pressure. Where a wood chisel is not readily available the case should be well protected and even greater care taken not to permanently damage the outer ring.

Take great care not to drop or break the dial glass once it is released by the outer ring's removal. No great effort is required to lift the outer ring if you work slowly and carefully around the ring..

Since I cannot supervise I have emphasised the care required to avoid permanent damage to the clock. If you lack the necessary skills and tools then ask somebody with experience to remove the outer ring for you. You should make it perfectly clear to your assistant that the glass is no longer held safely once the outer ring is lifted free. 

I accept no responsibility for any damage or injury (whatsoever) in providing this description of outer bezel removal. Think twice, or several times: Act once. (and then only with great care)

Once the bezel is free the dial glass can be placed safely aside. The hands must be removed before the dial and chapter ring can be lifted free. They lie on the case front centred by the inner sight ring. Only after their removal will the movement be exposed. The movement itself is held by three  screws which pass through rubber bushes with permanently attached nuts. Do not remove any other screws.  

Oiling:

I will not translate or describe the manufacturer's advice on dismantling the movement. The chances of correct reassembly are remote without considerable experience. You either have the skill and need no advice or you don't. If the clock is running well then it does not need repair. Do not repair that which is not broken!

All the axle pivots and the escapement should be oiled with clock oil. Avoid getting any oil near the contacts or their springs. The clock will not run with oil on the contacts! A tiny drop of oil is all that is required in the pivot holes surrounding the axles. Oil is best applied with the tip of a fine piece of wire dipped into a single drop of oil on a clean surface (a saucer?) then the oil carried to the pivot. Any more than this and the oil will run away from the pivot hole over time. Which will drain the bearing of oil by capillary action. So too much oil is usually worse than none at all. The oiling wire should be about the diameter of a fine sewing needle. If you press a fine needle into a wine bottle cork you will have a handy oiler. Just make sure it isn't a large needle or you will almost certainly over-oil the movement. The eye of a large needle will hold many times the amount of oil you need even for oiling a dozen clock movements properly.

If your idea of oiling any clock is turning a can of bicycle oil upside down over the movement then you had better stick to oiling bicycle chains. (even this is frowned upon in these days of special lubricants)  Refined bicycle oil (like 3-in-1) can be used for this clock but you should use a wire to carry only a tiny drop to each bearing surface. The amount of oil should be so little that it disappears into the bearing.

If you ask nicely your local clock repairer may sell you a tiny bottle, or phial, of proper, light, clock oil. Which is much better than bicycle oil and designed not to dry out for years. Nor cause corrosion between different materials. You only need the tiniest amount of oil for one clock so don't be greedy. Or it could get quite expensive too!

Most Telavox clocks will be 50+ years old and may never have been oiled in their lifetime since leaving the factory. If the clock is still running well and keeping good time I really wouldn't risk touching it. The risk is far greater to the clock from being dismantled by an amateur than being allowed to run without further oiling

Read the paragraph below before making any decision to remove the movement for oiling.


The Telavox runs very light with all the energy being supplied at the lightly loaded, escapement end of the gear train.  There are no massive springs driving the gear trains from the "slow end" like a "normal" spring driven clock With all the attendant problems of very high pressures and friction and wear on all the pivots and gear teeth.

Talking of which, you should never oil the teeth of any clock wheel or pinion. Only the escape wheel needs oiling and that comes from applying a tiny drop of oil to each of the contact surfaces of the escapement anchor. Certainly not from oiling the teeth of the escape wheel itself. Once carefully re-oiled the Telavox clock movement probably needs no more oil for at least another decade. (or two)
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