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A Gents' Pulsynetic Waiting Train video has been posted by Tony Martyr on YouTube:
http://m.youtube.com/watch?feature=youtu.be&v=VwSTKJxhaa4 it
Not only do we see the early [1918] C40A WT in action but are clearly shown how the WT drives the hands of the very large dial via lead-off work and the motionwork gearing.
An early feature is the lack of a roller on the pendulum drive armature. Later movements have a roller which pushes up against the impulse pallet. [i.e.The hook shape which extends to the right from the pendulum rod.] Despite the very obvious hook the drive armature only pushes upwards against the curved impulse slope between the hook and the tip of the pendulum extension. The hook itself is a red herring and never contacts the impulse pallet or roller despite appearances.
The time setting handle is missing from the front end of the worm and ratchet wheel shaft.
The brass counterbalance for the gathering pawl is flat and extended to the right. Later movements have a cast block to the far end to help balance the arm. The gathering arm is bifurcated in later movements for greater strength, to avoid twisting under load and to double the bearing area.
The hand setting dial pointer is large and round. Later pointers are squared and much reduced in size.
The contact assembly support post is oval, fixed and the major axis is horizontal. This is the opposite of later WT movements. Which have slots in the base plate to provide for horizontal adjustment.
The contact assembly support post is oval, fixed and the major axis is horizontal. This is the opposite of later WT movements. Which have slots in the base plate to provide for horizontal adjustment.
The stout steel pin extending forwards from the top of the pendulum rod is unique in my humble experience of WTs. It may have been to push the pendulum while avoiding the danger of trapped fingers. Though its very high position on the pendulum rod must have made it very hard work to get the heavy pendulum swinging from rest.
Alternatively: The pin may have been a simple mistake in assembly at some point in the movement's long life. A similar pin is missing from the main frame to the left of the inverted L-shaped lever.[Masking pawl] The pin would have had an adjustable, eccentrically bored cylinder to finely set the masking pawl's position relative to the gathering pawl and ratchet wheel.
When the D-shaped pin on the ratchet wheel lifts the masking pawl the gathering pallet [hook] slides on top of the masking pawl. The brief electrical signal then comes from the master clock and actuates the small electromagnet just below. This releases the catch which was holding up the masking pawl. The masking pawl drops and tooth gathering can then begin again for another half minute. The sequence repeats automatically unless the signal from the master clock is interrupted. In that case the masking pawl never drops and the hands on the clock dial[s] do not advance.
The video also shows how the master clock works and we see how it sends a short electrical impulse to the WT each half minute. The heavy wooden framework supporting the WT and large dial is ingenious.
The second video is from Clockworks: This has already been covered in an earlier post but is worth mentioning again:
While this second movement appears to be very similar to the first it may be up to 25 years later than the one shown above. It might even be post-war. Note the "bandaged" power electromagnet coils. This is an indication of a later movement. Earlier coils had visible wires insulated with tightly wound cotton or possibly silk. Later coils were covered overall in thick wax for more protection. The bandaged coil is the last in the series of improvements to the coils insulation and mechanical protection.
The deeply curved cutaway in the masking pawl of the waiting train mechanism is later. Despite the age difference this movement still has deep gold lacquered, brass components and the "bent knee" to the main frame casting above the power electromagnets. Later movements had a straight bar just above the large coils.
This movement still has the lacquered, cast brass, contact steady bars. Later movements had pressed steel, contact steady bars with more gentle curves instead of abrupt bends. Many components were plated steel in later movements.
Some earlier WT movements may have had their contact assemblies replaced with the later design during routine maintenance. One must then look to all the other design features for a better confirmation of age. Unfortunately the earlier black and later greeny-blue paintwork may have been painted over at some time. Though it may still be possible to find remains of the original paint in very inaccessible places. Particularly underneath. Though one should not deliberately damage the present paint in a search for the original.
The pendulum drive contacts are rather prone to oiling if the clock minder is too generous with lubrication to the Hipp toggle and V-block. Running a cloth with a suitable grease solvent between the contacts while they are pressed together may help. [Do not leave potentially combustible rags or fluids in the clock room! Some solvents can spontaneously combust if rags are left exposed to the air!]
The pendulum should really be brought to rest and the drive power switched off first before any maintenance. There is a serious danger of trapped fingers if the WT is left running. Not only from the heavy swinging pendulum and its cast rod but also from the drive armature. The large electromagnets have considerable power to trap unwary fingers via the rocking armature when activated. [Either accidentally during contact cleaning, oiling or during normal running!] The WT and its clock hands are easily advanced to time using the time setting handle on the front end of the worm shaft. One need only watch the time setting dial advance past its pointer below as the crank handle is turned.
The deeply curved cutaway in the masking pawl of the waiting train mechanism is later. Despite the age difference this movement still has deep gold lacquered, brass components and the "bent knee" to the main frame casting above the power electromagnets. Later movements had a straight bar just above the large coils.
This movement still has the lacquered, cast brass, contact steady bars. Later movements had pressed steel, contact steady bars with more gentle curves instead of abrupt bends. Many components were plated steel in later movements.
Some earlier WT movements may have had their contact assemblies replaced with the later design during routine maintenance. One must then look to all the other design features for a better confirmation of age. Unfortunately the earlier black and later greeny-blue paintwork may have been painted over at some time. Though it may still be possible to find remains of the original paint in very inaccessible places. Particularly underneath. Though one should not deliberately damage the present paint in a search for the original.
The pendulum drive contacts are rather prone to oiling if the clock minder is too generous with lubrication to the Hipp toggle and V-block. Running a cloth with a suitable grease solvent between the contacts while they are pressed together may help. [Do not leave potentially combustible rags or fluids in the clock room! Some solvents can spontaneously combust if rags are left exposed to the air!]
The pendulum should really be brought to rest and the drive power switched off first before any maintenance. There is a serious danger of trapped fingers if the WT is left running. Not only from the heavy swinging pendulum and its cast rod but also from the drive armature. The large electromagnets have considerable power to trap unwary fingers via the rocking armature when activated. [Either accidentally during contact cleaning, oiling or during normal running!] The WT and its clock hands are easily advanced to time using the time setting handle on the front end of the worm shaft. One need only watch the time setting dial advance past its pointer below as the crank handle is turned.
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