Ball Clock II ~ 12 O’Clock Ball Dump

by Jon Long Sr on June 21, 2017

One of the things I had to consider with the design of the Hour Selector mechanism was what to do with the balls that accumulated one every hour.  By the time 12 o’clock comes around the track holding these balls was filled to capacity.

Something had to be done to release (dump) these balls before 1 0’clock came around.

The trick was to find something in the works that only happened at 12 o’clock and no other time.

Then be able to trip another cycle to allow the 12 balls in the rack to exit.

Also and very important, the balls could not exit at the same time the clock was striking 12 since they used some of the same exit path back to the screw lift.

This could have caused a ball jam from balls hitting each other running down the same track.

When the hour selector is stopped by a ball in the rack, it engages another cam that opens a gate to allow that selected number of balls to move to the hour hammer trip area.  Because this happens immediately at the start of the selection at 12 o’clock, it is the longest rotation the cam makes.  At the end of the cycle to provide power to return the cam to its home position a chain is attached to it and a weight.  Now because this is the longest travel the chain will make, I had a spot that I could monitor.

By making an arm with a slot that straddled the chain and putting an adjustable collar on the chain, I was able to have an action occur only at 12 o’clock.  The collar contacts the arm and moves it up rotating a gear and turning a shaft that goes to the other side of the clock.

On the other end of that shaft is an arm that releases a clutch pawl to engage and clutch.

The clutch engages a cam, that when it turns, moves an arm attached to the gate holding back the hour balls.

The cam that moves the release arm for the balls is 285 degrees around from the engagement point of the clutch.  Because the shaft that the clutch is on turns are 2.5 rpm, the minimum amount of time before the gate is opened is 20 seconds and a maximum of 44 seconds.

It takes 18 seconds for all 12 balls to strike the hour. This allows a clear track for the 12 balls to exit when dumped.  And yes that was fun to figure out.  I wonder sometime what I got myself into.

For the next 12 minutes balls on the supply lift for striking will be diverted to fill up the lower track of the hour selector since twelve were used for the strike.

I soon discovered that I needed a way to keep pressure on the cam to keep the clutch pawl engaged.  I solved this by making a small spring loaded arm with a bearing to ride on the cam.  I cut an index slot on the cam to create a home position.  This made the engaging of the clutch dependable.

Now since this was the last major mechanism, it is time to do some base work.




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Ball Clock II ~ Base Construction

by Jon Long Sr on June 13, 2017

The Ball Clock was built on a .125 flat brass plate.  The walnut base was part of the glass dome I got when I started this project.  I purposely put off mounting the base plate to the walnut base to allow me access to the bottom of the brass base if needed.

Over the length of the project this turned out the be a good thing.

Now that everything is completed it is time to mount the clock to the wood base.  Because the drop on the track is minimum, it is very important that the clock be level.  I mounted a sensitive bubble level on the front of the base.

The easiest way to level something like this is with three points of contact.  This is like anniversary clocks that use three points of contact.  Four points are problematic to level.

I made three adjustable feet with knurled knobs for that adjustment.  Cutting threads with a lathe is an art and not within my current abilities.  I have the tools, just not the talent.  I used brass 10-32 machine screws for the shafts of the levelers.  The feet were turned from 1″ brass rod.  Felt pads were put on the bottom of the feet to protect supporting surfaces.

The first thing and the scariest I must admit was separating the clock mechanism from the brass base without throwing off the adjustments.  Once off, it was set it aside on another plate.

Because the clock runs on an asynchronous motor with 120 vac it was necessary to route the power cord under the base and still be able to disconnect it if needed.  This was done using a Euro Connector by the motor.  It has small screw connections which kept things clean.

The feet had to go through the wood base and still support the wood base and clock.

Collars were mounted to the brass base for the feet and “T”nuts were used to attach the wood base to the brass base.



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Ball Clock II ~ Housekeeping

March 25, 2017

March was pretty much taken up with fixing some things that I had been putting off for a while. I knew it would require a fair amount of disassembly to get to the areas that needed attention and then the arduous task of cleaning and putting it all back together. I wasn’t satisfied with a […]

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Ball Clock II ~ Hour Ball Selector Drive

February 21, 2017

For the last couple of months I have been operating the Hour Ball Selector by hand to test it. The time has come to power the main shaft of the selector.  These are the things to be considered for the drive: The rotation of the shaft has to be triggered by an hour ball when […]

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Ball Clock II ~ Hour Striker Rebuild

January 7, 2017

Not everything will go as planned in life and none truer right now than this project.  Back from Christmas vacation and back at it. My original design for the hour striker was pretty simple.  The weight of a ball would cock the hammer and a cam would release it at an interval to provide a […]

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Ball Clock II ~ Hour Ball Selector-5

October 20, 2016

The Ball Selector needed to return to its home position at the end of the cycle. I chose to use weights rather than springs for this because springs will increase tension when expanded and weights are a constant force. The main shaft of the selector mechanism makes a full revolution during the process.  The Ball […]

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Ball Clock II ~ Hour Ball Selector-4

October 18, 2016

After some testing it became apparent that an Index Plate was necessary to hold the selector arm in place once it has been extended. It was important that the Index Plate was in line with the position of the balls in the upper & lower track.  This is so the vertical piece on the selector […]

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Ball Clock II ~ Hour Ball Selector-3

September 11, 2016

Some progress since the last post, albeit slow.   The supports for the selector assemble have been installed complete with bearings upper and lower.  The trick was to get the angle right as the selector has to follow the slope of the magazine.  (Photo-1) Because I’m using a jig to work on this assemble, it […]

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Ball Clock II ~ Hour Ball Selector-2

August 28, 2016

Now that I have the jig to hold the Hour Ball Magazine, I am able to see how things fit. There are a number if parts that had/have to be made for the selector mechanism.  The first was the slides that will cam out to separate the proper number of balls to release to the […]

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Ball Clock II ~ Hour Ball Selector

August 20, 2016

The hour balls appear to be moving through the striker mechanism smoothly now. It is time to focus on the section that will select and release the proper number of balls to the striker. Back in February I talked about the hour Magazine and its eventual function.  That was to act as a counter for […]

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