The Haller Time Bomb (GTB) Anniversary Clock

1 Copyright Mervyn Passmore 20091 The Haller time bomb Clock by Mervyn PassmoreCopyright Mervyn Passmore 2009 The Sigfried Haller time bomb Anniversary ClockThis unusual Anniversary Clock has beennicknamed The German time bomb becauseit normally ticks away happily for years, butsuddenly and without any warning, its toothlessratchet can slip and the mainspring will unwindnoisily. It can destroy itself in the process, andcan cause injury to anyone near it at the time . Itcan shatter its own dome as it is an extremely dangerous Clock and youshould consider very carefully before puttingit on public or domestic display unless youare sure it is only partly you are considering working on the movement,either to service or repair it, you need to be awarethat this Clock was not nicknamed The GermanTime bomb as a term of endearment but becauseit can and does cause injury without any warning,and it can do so at any time , ticking or not.

2 Ifyou are not an experienced Clock repairer, donot attempt to work on it. Put it in a strongcarton, cover it with an old towel, seal the boxand mark the box appropriately. Store it awayfrom accidents occur when owners unwittinglyundo the four screws on the back plate, expectingto find some sort of mechanism inside. Do notundo these screws unless you know that themainspring has been let down Clock is immediately recognisable by theunusual shape of the not start dismantlingby undoing these screwson the back.

3 If you do,the Clock may Mervyn Passmore 20092 The Haller time bomb Clock by Mervyn PassmoreCopyright Mervyn Passmore 2009 The designers at Sigfried Haller must have started with a clean sheet of paperwhen they designed this Clock . It has barely anything in common with previousand later mechanical clocks:1: The mainspring, instead of being a flat coil wound round an arbor, is anaturally coiled spring that is reverse-wound onto a plastic : There is no conventional ratchet. Unwinding is prevented by a coiled wirespring on a : The pendulum does not hang on a suspension but floats on opposing : The train is skeletonised on the front plate, not mounted between the : The escapement is at the bottom of the front first glance this may seem totally unique, but further consideration willshow that the designers were way ahead of their time .

4 Some might say too farahead, but many of these design features were to become quite standard inlater quartz clocks, particularly the method of pendulum suspension by useof is nothing special about the way this Clock needs to be cleaned, lacqueredand lubricated, but the dismantling and re-assembly can be daunting anddangerous to a repairer who has not worked on one before. The purpose ofthis document is not to explain how to repair clocks but to warn of the dangersinvolved and to give an insight into what to find inside this movement.

5 Treatthe Clock as if you were disarming a mainspring unwound, the naturally coiled spring is happilycoiled around the lower storage drum. In thissituation it is relatively harmless, with hardly anypotential wound, the spring is coiled around the upperwinding drum. It is coiled in the opposite directionto its naturally coiled state, and therefore hasenormous potential Mervyn Passmore 20093 The Haller time bomb Clock by Mervyn PassmoreCopyright Mervyn Passmore 2009 The spring is prevented fromunwinding by a spiral wirespring fitted to a bush on thewheel that would normally bethe barrel, which also goesover part of the upper plasticdrum on which the spring iswound.

6 The tail of the spiralspring fits into a slot in cross pin through the winding arbor locates in agroove in the back of the drum. When the windingarbor is turned in the winding direction, the plasticdrum also turns due to the cross pin, which in turnrotates the tail of the spiral turned in this (anticlockwise) direction, thespiral spring expands and is therefore free to move on the brass bush, and thespring can be wound. When tension is gently taken off the winding shaft, andit is allowed to turn back a few degrees, the spiral spring tightens up on thebrass bush and the drum, acting as a of the time this operates correctly.

7 The sudden and dramatic unwindingthat these clocks are known for seems to occur when the coils of the mainspringbind. In a conventional barrel, one hears a clunk as the coils rearrangethemselves after binding. In this Clock , if the coils bind on the winding drum,or the spring fails to coil back on the storage drum, tension on the spiralspring can reduce to the point when the ratchet system can fail and thespring unwinds Mervyn Passmore 20094 The Haller time bomb Clock by Mervyn PassmoreCopyright Mervyn Passmore 2009 DismantlingPlease remember that throughout this procedure you should wear eyeand facial protection, stong gloves.

8 And all exposed skin should be coveredwith suitable protective wear. The wound spring can slip at any time ,and if it does, you will probably be injured if you have not protectedyourself properly. Please don t ignore these warnings. Don t confuse themwith mandatory health and safety warnings that appear in technical documentsto protect the author. There is a real danger of the mainspring cover is a three sided folded piece of metalthat fits in the two pairs of grooves in the sides ofthe plates.

9 If it won t pull up, you can slaken thescrews that hold the backplate in positionanticlockwise by a maximum of one quarter of aturn to release to pressure. There is a dangerousmainspring between the plates, so do not loosenthese screws more than one quarter of a turn, orthe spring may slip and you may be injured. Besure to tighten the screws immediately after raisingthe down the no click to release, letting down the spring without waiting for it tounwind normally can only safely be achieved by allowing the Clock to unwindrapidly but in a controlled the pendulumTo let the Clock unwind, you will need to remove the pendulum and the escapewheel.

10 Put some fine pegwood or plastic through the spokes of one of theupper wheels of the train to prevent it from turning. Remove the lower skeletonfront plate and carefully remove the pallets and the escape wheel. Lift off thejewelled upper pendulum support and remove the pendulum. Ease theadjustable collet on the helical suspension spring upwards and off its pendulum is now free to lift Mervyn Passmore 20095 The Haller time bomb Clock by Mervyn PassmoreCopyright Mervyn Passmore 2009 Make sure that the remaining pivots are well removed the pendulum, you can allow the train to unwind Usingsomething soft like a piece of cardboard, restrictthe speed at which the train can unwind.