Gustav Becker Chiming Wall Clock with Two Mainsprings

This clock has an unusual movement. Most Westminster chime clocks have three mainsprings (or weights) – one for the time (usually in the center), one for the quarter hour chime (right) and one for the hour strike (left). This clock has only two mainsprings. (I’m not sure if this was done to save on cost, because it made the movement more complicated.) Also, the clock does not do Westminster chime on the hour, it just strikes the hour. The case is 29 1/2″ tall and 14 1/4″ wide, and the dial has a 6 3/4″ minute track.

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How the two mainsprings are connected

The left mainspring powers the hour strike gear train (gears on the left as viewed from the front – see first picture above). The right mainspring powers the time gear train (gears in the center).

There are three gears outside the back plate that run the quarter hour chime. The left mainspring barrel’s ratchet is mounted on rear gear 1 (see second and third pictures). The small brass gear connects gear 1 to gear 2. Gear 2 then drives the first gear of the chime gear train (visible at left in second and third pictures).

The result is that both mainsprings drive the quarter hour chime, and both mainsprings unwind at the same rate as the chime plays.

The clock chimes the first, second and third quarters, but merely strikes the hour (no chime). The mainspring would run down too quickly if the clock chimed the hour (it barely has enough power for an 8 day run as it is).

Repair job 7775. I straightened two bent teeth on the right mainspring barrel. I trued the second strike arbor, and moved its rear pivot away from the barrel to depth it properly (so the gear turning action was smooth). I had a new gear made for the left mainspring barrel, and polished the pivots and installed 19 bushings.


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