Horology

 At the age of eight I started getting interested in clocks and took great delight in taking them to pieces and see how they worked. It must be said that not one of these ever worked again!!  A few years later and many dead clocks I had turned my interest  to radio sets and electronics and at the age of 11 I knew what I wanted to be when I grew up.

A year ago I thought back at my previous record in the clock department and decided to reverse the trend of destroying clocks and actually put life back into clocks by redesigning and doing something a little different!!

The first project was a clock for the conservatory whereby I wanted a large skeleton type dial clock that was almost three feet  in diameter.

NO 1   - CONSERVATORY CLOCK

The idea was to make a skeleton style very large faced clock. The mechanical parts would be on show behind protective glass effect panels. A key aspect was to have the clock continuously  powered rather than the traditional key wound clocks.

The size chosen was 800mm diameter and lexon was used for the glass effect panels. An old electric master clock was used which would have been used in a factory, school, raileway station etc.

This T&N (Telefonbau und Normalzeit) electric master clock would have been manufactured in the 1960s or 70s and will drive a number of alternating polarity, one minute slave dials. It used to have a very plain light blue enamelled steel case with a fully glazed door. The escapement is a dead-beat type, and the 3/4 second pendulum rod is of wood with  a spun brass bob. The electric rewind mechanism consists of a large flywheel and a small weight suspended on thread, all mounted on a Bakelite back plane. The rewind impulse arrangement consists of a pair of coils and armature mounted parallel to the back plane, A rotary switching mechanism for deriving alternate polarity pulses to drive the slave dials, is to the lower left. Power is transferred from the flywheel to the movement by a short helical spring which also acts as maintaining power. Power is then divided between the main drive to the dead beat escapement and the slave switching. Alternate polarity slave dial pulses are triggered by means of a cam on the seconds arbor behind the dial.

This clock is fitted with a programmer which.is used to to switch other functions such as bells or lamps to be set at 5 minute intervals over a 24 hour period, and to be suppressed on certain days of the week. The large wheel under the dial is the 24 hour programmer wheel into which small pins were inserted for each event to be switched.

NO 2   - KITCHEN CLOCK with Grandsons in Mind

The project was to make a clock that would capture the attention of our two grandsons aged nearly two and three. Also Rona wanted a bit of Blackpool in the design. Some one said a simple clock .... ahem

So carrying on the lines of using a master clock housed in a clear paneled case the hunt was on for one that was dramatic and made lots of noise and movement!!  The idea was to have sound, light and visual effects to show the grandsons a unique, alive and interesting clock whilst being functional and informative!!!

 

The clock displays and features the following:-

• Seconds

Half minute (30 secs)

Minutes 

Hours

24hr clock

24hr programmable timer

Day of the Week

Lunar Moon Phase

Tidal Ebb and Flood times in hours for two locations
                            

Striking the hour on vintage bell (the time of hour) and half hour

Flashing bright LED contacts light - every 30 seconds

Illuminated clock mechanisms with 16 different colours and remote control

Moving mouse around the clock on the hour

 

The following was the result.............

 

FOR THE TECHNICAL MINDED the following is how the clock works.

 

The main parts of the clock are as follows:-

 

• Main pendulum “Master Clock”
• Slave minute/hour mechanism
• The Pulsynetic bell ringer. (programmable contact maker)
• Slave seconds divider mechanism for striking the hour and half hour
• Electric striking clock mechanism with bell operation
• Lunar moon phase clock
• Tidal Clock
• Illumination control and light system
• Moving mouse system (not operational)
• Power supply and power distribution

•   Main pendulum “Master Clock” 

• The main heart of the clock is a 1960’s  Gents’ (of Leicester) Pul-syn-etic master clock. It has a nearly free swinging pendulum adjusted to 1 second per half cycle. Watching the clock operate for a few minutes will reveal its operation. The pendulum moves a follower which trips an escapement wheel once every cycle. The wheel is fifteen teeth (thirty seconds) around and at one point there is a deep notch. This causes the actuator to slightly move upwards on the next right swing so that it fouls a vertical spring latch on the right hand side.

You now need to watch carefully because everything happens quickly. The latch releases a bar which contains a small roller. This rests on the pendulum follower and as it swings to the left it rolls off the edge and down the side. This side piece is angled so that the weight of the roller and impulse-bar mechanism gives the pendulum a slight nudge to keep it swinging. So far this has all been mechanical, however when the roller reaches the bottom (when the pendulum is roughly in mid swing,) an electrical contact is made at the lower left of the impulse-bar. This enables a current to flow around the circuit which includes a large double coil solenoid at the left. The solenoid pulls a long bar towards itself which shoves the impulse-bar back to re-engage into its latch before the pendulum can swing back again. In the process it disconnects the current so that the solenoid-bar falls back again. This is what creates the loud “clunk” every thirty seconds.

The pendulum rod is flat invar steel with a threaded extension welded to the bottom. The bob is a cylindrical bronzed steel can 254mm (10") long by 57mm diameter (2 ¼") diameter, perhaps containing large lead washers weighing a total of approximately 4.9Kg. The bob is a close but free fit to the rod and a cast metal circular disk at the bottom allows up and down adjustment on the threaded part of the rod. The whole is suspended by a strip of spring steel clamped to the rod and also to a pivot which allows a small amount of front to back movement.

There is a pull string on the right that, when operated, causes the follower to release the latch on every swing of the pendulum. This is to advance the clock for Daylight Saving Time. It takes four minutes to advance one hour.

The current which re-engages the latch also flows to slave mechanisms, one of which is the dial on the front. These get the same pulse every thirty seconds to move the hands half a minute at a time using a solenoid operated ratchet. It is this feature that gives the clock its name and makes it a master clock (or transmitter as the manufacturers call it).    The master clock pulses feed two slaves at the top. These are the main 24 hour programmable wheel and the minute/hour main slave mechanism.

 

• Slave minute/hour mechanism

• The GENTS slave mechanism is a standard electromagnet that attracts its armature which is pivoted at the lower end of the diagonal bar, and releases it after about 1/5 second (the duration of gravity arm resetting). As the armature is released, the indexing pawl at the top pushes the large 120 tooth wheel round by one tooth and thereby moves the minute hand by half a minute. The hour hand is driven by conventional motion work. The pawl at the top left stops the minute hand being driven backwards.

 

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• The Pulsynetic bell ringer (programmable contact maker)

• The contact maker can be thought of as a clock, or time switch, with three dials which rotate against fixed pointers. These indicate the day of the week as well as showing the (24 hour) time and the minutes of the hour: This device could be used to ring electric bells and and sound factory sirens..
   

Through a simple system of gears the programmer's large ring is advanced at half minute intervals by the slave mechanism. On the impulse dial mechanism itself is the minute dial. The electromagnet is activated by the master clock's brief impulses at 30 second intervals. The minute wheel is rotated by the ratchet (or impulse) wheel as one unit.  All turn once per hour driven by the electromagnet.  The contact fixes the duration of bell ringing to about 8 seconds.

The day of the week wheel is really a simple cam driven by a pinion on the 24 hour wheel. The day of the week wheel has a normally-closed, bronze, contact finger rubbing along its lower edge. At the weekends an optional cutaway on the edge of this wheel allows these sprung contacts to open. Thus breaking the bell circuit. Which stops the bells ringing all weekend until the raised edge finally returns on Monday. Closing the contacts again.

The 24 hour pin wheel has holes around the periphery at 5 minute intervals. It is driven by a pinion from the minute wheel of the slave movement. When a stout, tapered, timing pin is placed in any of these holes it will eventually arrive at the bell contacts at the extreme left  of the mechanism. The pin closes the contacts, completing the bell circuit at the time shown on the pin wheel dial.

Any single contact in the programmer's circuit cannot ring the bells. All must be closed at the same time. The bell contacts are closed by the timing pin for several minutes.
 

• Slave seconds divider mechanism for striking

• The timing of the seconds slave unit comes from a Infra Red sensor located at the pendulum which on every half cycle movement of the pendulum breaks the beam which sends a pulse to a counter. This counter divides the seconds pulse and activates the seconds slave unit every fifth second. This means that the seconds slave dial moves only every five seconds. Also, the seconds slave unit has the standard mechanism modified to complete the requirements of the striking clock mechanism with the indexing pawl at the top pushing the large 120 tooth wheel round by two teeth instead of the usual one tooth: thereby moveing the minute hand by one minute instead of once every thirty seconds. The hour hand is driven by conventional motion work. The pawl at the top left stops the minute hand being driven backwards. The slave features a large brass cog with 60 teeth meshing with an intermediate cog which connects to the cog of the striking mechanism on the top left of the clock.

 

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• Electric striking clock mechanism with bell operation

The problem with the 24hr clock is that whilst it can be arranged to trigger a bell evry hour it wlll not identify what the hour is by the number of strikes. To do this a mechanism is used from a 1950 ‘sectric’ electric mantle clock made by Smiths. The basic clock and striking mechanism has been extensively modified whilst disgarding the mains driven motor and timing system. The large input wheel cog drives the minute input so that timing of this input is synchronised with the pendulum.  The striking mechanism has been modified for a 12V micromotor drive which strikes the hour and half hour. This moves the hammer which has a brass plate arrow. This in turn interrupts an Infra Red sensor and sends an impulse to a driver module, which causes a relay to operate a solenoid. This solenoid has a fine nylon cord attached to a 1930’s school hand bell and operates the bell clapper in striking both the hour and half hour timed by the master pendulum. Selection of the number of strikes per hour is done by the mantle clocks conventional snail mechanism.

 

• Lunar moon phase clock with rotating moon

This uses a standard electrically driven moon phase drive hidden within the woodwork. The battery has been removed and 1.5V is derived from a large battery hidden in a vintage 1930’s Bakelite mens shaver case mounted lower down. The base features brass cogs and wheels disguising the modern nature of the hidden plastic mechanism. The brass cog on the top of both the moon phase and the tide clocks are from a standard old clock mechanism that housed the main and striking springs. The brass thin tube has +12v lead feeding the power to the inside LED lighting up the moon internally, the negative being the tube itself. The moon has black paint on on hemisphere whilst the other side has white paint daubed on a plastic sphere to give an impression of the moon surface when lit internally. The hidden motor turns the moon to show the moon phases with one rotation every 28.5 days. Looking directly at the moon sphere shows the different stages of phases with the black and white aspects visible.

 

• Tidal Clock mechanism

• The Tidal clock mechanism is similar to the moon phase mechanism just with different gearing. It revolves twice a day coinciding with the tide which can be preset to a location on the coast. It shows the ebb and flood tides with hours to go. The stationary vertical needles can be moved to show the tide at two different locations in the country. This plastic modern battery drive mechanism is again hidden from view with various brass cogs disguising the method of drive. The centre cylinder is a plastic pipe with transfer printing applied showing the hours to go before high tide and low tide. The tube is rotated and the LED, with power being fed from the top, is illuminated showing the scale on the tube. The top cogs and parts are taken from old clock mechanisms.

 

• Illumination control and light system

• The extensive illumination system utilises LED RGB strip light technology. This is controlled by a remote control unit which will select 16 different colours and activate these in various sequences and fade effects or plain individual colours. The top section has a different colour than the pendulum section. The control module is housed behind the large 24hr wheel and communicates with the remote control unit via Infra Red.

 

• Moving mouse system (not operational)

• Upon striking the hour the aim was to have a mouse running up the clock, around the top circle of the clock and back down the side of the pendulum box. The mouse was connected to a thin nylon wire that rotates around a number of pulleys situated around the extremes of the clock. The box lower down near the pendulum houses the drive motor and electronic sensor that stops the mouse in the box. Upon striking the clock on the hour the mouse sets off on its journey up and around the clock before going back down and reaching the box where the module senses the presence of the mouse. Once triggered it stops the mouse in the box.

Unfortunately at the time of writing the mouse system worked but was not reliable as the mouse kept coming off the pulleys at the top of the clock. It will be revisited!!!!

 

• Power supply and power distribution

• The mains cable is connected to a fuse box which then feeds the main power unit located in a large bakelite Gents slave box. The 240V input is fed to a master on off Bakelite switch before going to a switched power supply unit that has an output of 12V DC used to feed all power requirements. The exception is the 1.5V of the moon phase and tidal clocks which are fed from a large battery located in a 1930 bakelite shaver box. Two meters monitor the 12V and the current for the main pendulum reenergising electromagnet. The contacts have a bright LED that flashes when the contacts are closed to simulate contacts arcing. Various mechanisms are fed the 12V via four fused circuits. The two rheostats on the right side adjust the 12V current feeding the slave drive mechanisms. The large slider rheostat on the left adjusts the current to the pendulum relay drive maintaining the pendulum swing.

 

NO 3  - KITCHEN CLOCK with Grandsons in Mind

This project is completely different in every respect and IS to make a clock that resembles a ..........