Pictures

S. Haller / Elgin 400 day "German Time Bomb clock", circa 1980

This attractive 400 day anniversary clock at first blush looks very much like others from this period, but a closer look reveals that it is quite different! The movement is skeletonised on the front plate. Nothing is between the plates except the unusual reverse-wound main spring. The pendulum floats on opposing magnets below. Unlike conventional 400-day clocks, this clock uses an helical balance spring. These clocks were made by Siegfried Haller of Germany and this one has the Elgin name. These clocks withdrawn from the market in the 1980's and this example was likely made shortly before.

In spite of its innocent look and charm, this is an EXTREMELY DANGEROUS clock that has been nicknamed The German Time Bomb. It can tick away happily for years, then suddenly and without any warning, its toothless spring lock (ratchet click in other clocks) can slip suddenly releasing the 20 ft. long main spring and destroying itself in the process! It can shatter its own glass dome as it explodes and can cause injury to anyone near it at the time.

The problem stems from the unusual reverse-wound main springing. The powerful open main spring is formed on the lower spool and the outer end is attached by a screw to the upper plastic spool. The winding arbor turns the upper spool by a small steel pin. When the clock is wound the spring is spooled onto the upper spool backward from it's normal resting shape to greatly increase the energy stored. There is no conventional click and ratchet, but a coil of wire wound around the winding arbor that allows it to rotate in one direction but grips like a Chinese finger trap when it tries to unwind. Unfortunately the operation of this devise is not very reliable. If it "lets go", or if the plastic spool breaks, or the drive pin breaks, or the spring breaks while wound, the clock can literally explode! I believe these clocks were removed from the market in the 1980's and for good reason.

Servicing these clocks can be dangerous and challenging because there is no way to safely let down the main spring other than letting it run completely down. Those who insist on running these clocks are often advised to just wind them enough to run for 8 days instead of 400. My advice is do not attempt wind these clocks at all. The spring in the clock shown is completely unwound and the clock is a non-running decoration.




Not for sale
(returned to owner without being repaired)

The information on this page is believed to the writer to be correct at the date of posting but is presented with no guarantee expressed or implied. Pictures were a true representation of this clock at the time of posting but may not be current. Please contact me if you believe that any of the above information is incorrect, or if you wish to share additional information, or discuss this clock.

Unless otherwise credited, the pictures and information on this page are the property of Robert H Croswell & Greenfield Clock shop, 4180 Main Street, Trappe, MD 21673 and may not be sold or used for commercial purposes without permission. © 2016

email:  bobby@greenfieldclockshop.com