17-06-2013, 07:17 PM
Ok, so another day with some free time so I opened the box marked 'Junghans ATO' and then remembered it was actually a box of bits bought at my local auction for £2 a year ago. This was an impulse buy at the time. I didn't want it to go down the tip and I thought that it would provide a good pair of hands and a few screws if/when I threw it away later.
This glass-dome ATO clock dates from the early 1950s and is fairly simple. A 1.5V battery is connected to an operating coil through a pair of normally open contacts. The swinging pendulum carries of a magnet which passes through the coil and also closes the pair of contacts briefly as it passes through the lowest point of the swing. The resulting current in the coil creates a magnetic pulse which repels the pendulum which then opens the contacts again. There is a ratchet arrangement to prevent the contacts from closing on the return swing of the pendulum. This is a simple arragement, but was unreliable due to the need for critical mechanical adjustment of the moving parts and the contacts themselves which tended to become corroded over time.
I removed all the parts from the bags and tobacco tins, then sorted them to assess what was missing. The suspension spring was broken, which was probably the reason for it being taken apart as they are cannot be replaced in situ. Some of the small M1 and M1.2 screws were missing as was the glass dome. The movement did not operate the small pair of electrical contacts. Other than that, it was restorable..... but was it going to be worth it as a new glass dome would be prohibitive. This dome is classed as 'large' and needs to be 165mm to fit the slot in the base.
The bits to repair my Kango concrete breaker had arrived so which repair should I attempt today? I opted for the clock because if this failed, I could repair the Kango and test it on the clock afterwards.
I sorted the parts for the base and cleaned and polished them before reassembling this as a starting item. A bonus was that the fumes from the Horolene killed all the flying ants that had invaded in the kitchen. It looked a bit like the 'Battle of Britain' over the skies of Britian as they fell into the sink in great numbers.
The base was finished and 'before' and 'after' pictures are shown below.
This glass-dome ATO clock dates from the early 1950s and is fairly simple. A 1.5V battery is connected to an operating coil through a pair of normally open contacts. The swinging pendulum carries of a magnet which passes through the coil and also closes the pair of contacts briefly as it passes through the lowest point of the swing. The resulting current in the coil creates a magnetic pulse which repels the pendulum which then opens the contacts again. There is a ratchet arrangement to prevent the contacts from closing on the return swing of the pendulum. This is a simple arragement, but was unreliable due to the need for critical mechanical adjustment of the moving parts and the contacts themselves which tended to become corroded over time.
I removed all the parts from the bags and tobacco tins, then sorted them to assess what was missing. The suspension spring was broken, which was probably the reason for it being taken apart as they are cannot be replaced in situ. Some of the small M1 and M1.2 screws were missing as was the glass dome. The movement did not operate the small pair of electrical contacts. Other than that, it was restorable..... but was it going to be worth it as a new glass dome would be prohibitive. This dome is classed as 'large' and needs to be 165mm to fit the slot in the base.
The bits to repair my Kango concrete breaker had arrived so which repair should I attempt today? I opted for the clock because if this failed, I could repair the Kango and test it on the clock afterwards.
I sorted the parts for the base and cleaned and polished them before reassembling this as a starting item. A bonus was that the fumes from the Horolene killed all the flying ants that had invaded in the kitchen. It looked a bit like the 'Battle of Britain' over the skies of Britian as they fell into the sink in great numbers.
The base was finished and 'before' and 'after' pictures are shown below.
