Thursday

Time Machines website:

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While searching online for my regular dose of "gents+pulsynetic+waiting+train" I just came across a fascinating website. With lots of illustrations of electric clocks. Primarily of American clocks though with some exceptions. 

The image [right] of a C40A WT and turret clock dial  was borrowed [and cropped] for educational purposes. There is no attribution as to the owner or author of the image or the WT installation. 

Scroll down to near the bottom of the page for the full sized WT image.

Click on the image for an enlargement.
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Friday

Gents' WT [sealed] motionwork.

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The first image nicely shows the sturdy construction which safely hold the large hands of a turret clock dial. Note the hefty casting supporting the minute hand. The simple fixing bracket is perfectly acceptable for an indoor, turret clock exhibition. It would not do [at all] for an exposed dial!

Exposed clock hands not only have to keep accurate time but are subjected to gales, icing, wind blown debris and everything else the elements can throw at them. Resistance to rusting is a serious matter over very long periods of exposure without easy access. 
  
Gent's also made sealed motionwork units to protect the [normally bare] gears from dust and debris. Tower clocks and their lead-off components are often subject to very dirty conditions in elderly buildings. Most older roofs have no under-felt and are subject to massive temperature swings. Motionwork can also be subject to the outside elements blowing between the roofing tiles. Or even through the dial aperture through which the hands are driven.

Sealing the motionwork within a closed container provides the rare chance [with clockwork] to apply a long-lived lubricant. Without the risk of contamination from the often-dirty environment. Motion work is often housed in poorly sealed roofs and towers. There is the risk of falling whitewash in stone and brick buildings. With the added risk of woodworm dust and birds nests in all others. Larger birds can fill a tower with decaying twigs and nesting debris over time unless the open louvers are wire mesh screened.

Here is an image of the "business end" of a turret/tower clock, hand fitting system without the hands. Both the minute shaft and the hour pipe are squared for a solid drive to the hands. A screw on the end of their minute hand shaft provided a simple and secure fixing by threaded nut.

While a securing, spring washer, with locking screw, is provided for the hour hand. The hour hand fits onto its machined square on the pipe first. Then the square hole in the washer is fitted over the pipe. Rotating the washer by 45 degrees brings the sides of the square aperture into the slots provided by the hour pipe. The screw stops the washer from rotating away from the locked position. A very simple, but robust and reliable, fixing. The spring washer is likely to be made of phosphor bronze for very long life.

A screw-threaded barrel has large screwed rings to fix the assembly firmly onto the dial board and allow some linear adjustment. In this case the length of the barrel suggests a dial board or wall about 3-4" [70-100mm] thick. Longer and shorter threaded barrels would be specified for various dial and wall thicknesses at the time of ordering and later installation.

Here a sealed motionwork is housed in a cast, protective cylindrical can or case. A short lead-off rod, with typical universal joints at each end, is seen fitted between the WT output shaft and the motionwork housing. The universal joints provide for thermal expansion and misalignment without binding. The outer screws [with washers] are not tightened but merely avoid dislocation of the forked and pinned joint arrangement. Some of Gents' universal joint designs have a thickened centre section to the pinned half to ensure the joints remain safely together. But still allow the pins to slide freely in the slots without friction.






The inside of the cast, metal case shows the gears embedded in a complete fill of lubricating grease. The input end of the minute shaft is protruding. Oil would easily run out of such a simple container over time. While grease stays in place and will offer long life without any maintenance at all. If the grease should harden over time it can leave bare tracks where the gears rotate. While a grease which softens with higher temperatures would allow the grease to slump back into contact with the gears.
The large support bearing for the hour pipe is seen here just above the surface of the grease. The closing cap is provided with threaded screw holes for dismantling and grease replacement at long intervals.
Here the complete motionwork components are shown free of their housing. The brass hour pipe, with attached gearwheel, lies at the top. The steel minute shaft lies in the middle ground with its fixed pinion on the right. While the pair of meshing gears [larger wheel and smaller pinion] lies in the foreground. The motionwork case, sealing cap is at top right and provides bearings for some of the components.

The sealed gearing arrangement is identical to open motionwork. Using combinations of different metals ensures that the minute shaft does not wear rapidly against the inside of the hour pipe. Nor will they rust fast together over time. As would a steel minute shaft in an iron hour pipe. The combination of dissimilar metals runs together with low friction without the galling expected of using similar metals.[Steel on steel is usually a bad choice, for example] Gents' were early user of stainless steel and hard chrome plating to ensure maximum longevity. The minute shaft [minute arbor in clock-speak] is probably made out of stainless steel.

For the clock enthusiast finding original components like these is all part of the pleasure of owning a WT turret 'clock' movement. Very often demolition crews will see the value in saving the clock movement from a long-disused factory or office block. Since it can be so easily turned into cash. However they will usually ignore the motionwork and lead-off work as being too insignificant to be worth the trouble of dismantling it. Nor is there much metal scrap value to be had. Access to exterior clock hands is very likely to remain difficult to impossible on old, industrial buildings. So all these vital parts are usually lost to the collector.

There must be original WT installations still in use. Though maintaining them must be very difficult without skilled help. Or the continued employment of trained, existing staff. Not that long term employees are likely to be found in our modern, ephemeral world. It is so much easier [and cheaper] these days to simply replace everything mechanical with a compact electric motor. Fitted just behind the dial, switched on and usually forgotten. Modern clock installations will often have a computerized "box of tricks" to ensure automatic summer time changes. Thus, has turret clock practice changed to match the latest technology, yet again.

Click on any image for an enlargement.
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Thursday

Gents' WT 'open' motionwork.

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I have been kindly sent some excellent images of various Gents' WT motionworks. These would have been connected to the lead-off rods from a WT movement. Motionwork is a simple four gearwheel train [in two pairs] to reduce the 1rpr  [1 revolution per hour] lead-off [minute shaft] speed [from the WT] by 12:1. The simple gear arrangement drives the hour hands on a public clock dial once in 12 hours from the minute hand drive input.

The first image shows an (almost hidden) WT driving the large, bare hands of a [missing] dial which might easily be 6' [2m] in diameter. A second WT movement is situated on the wall in the background. The active WT being seen end-on, in lighter grey paint, almost hidden behind the clock hands. Part of the bottom half of a controlling, electric master clock is seen on the extreme right.

Motionwork has another important task in supporting the large and [often heavy] clock hands without adding too much friction. The inner shaft carries the minute hand concentric within the outer hour pipe which carries the hour hand. Arrangements are usually made to secure the hands against rotation under their own weight or when covered in ice. Or even when supporting a perching flock of birds. The security of the hands in all weathers is obviously a very high priority to avoid injury to life or property below the raised clock dial. A hand falling from a great height would cause very serious harm!

Note how the thin metal hands are typically ribbed along their length for stiffness without added weight. The counterweights for the hands are often hidden behind the short extension beyond the hub. As can be seen from the rivets in this case. Alternatively the counterbalances can be fixed direct to the minute shaft and hour pipe within the safer environment of the clock room. This arrangement saves adding overhanging weight to the very exposed clock hands. Counterbalances for the clock hands are quite normal practice for the hands of even quite small public clock dials. When the hands are not counterbalanced they have to be lifted uphill for one half of their rotation. They will then try to "run away downhill" on the second half. This would not help accurate timekeeping with most turret clocks. Which are usually weight driven and "friction governed" by their gear trains and escapements.

Motionwork can be "open" [as seen here] or housed within a protective case. Dust and dirt being common factors in clocks rooms and bell towers. The following images show open motionwork with exposed gears seen from many different angles for greater clarity.

The usual arrangement is two pairs of gears giving speed reductions of 3:1 and a 4:1 ratio in series. Being in series the two ratios can be simply multiplied by each other to give the final drive ratio. [12:1]

The substantial pairs of brass [or bronze] gears are well seen in these images. Avoiding lubrication to the gear teeth will prevent dust adhering to them which would cause accelerated wear. It is normal practice not to oil or grease most clock gears. Falling dust can then drop through or off the gear teeth without adhering. Gears are known as wheels [large] and pinions[small] in horological circles.

The projecting, silver coloured, double forked device is a universal joint [or expansion coupling] to the leading off work's shafts, pipes or rods. These joints allow for the movement of the building under settlement, in changing weather and temperature without the lead off work binding. This is important because most lead off work is situated in exposed and draughty conditions in towers and roofs. Often attached to ancient timber constructions. The temperature can plummet in winter and soar in high summer. The sheer length of many lead off systems allows considerable changes in the active length of the metal shafts and pipes. This is due to the linear coefficient of expansion [and contraction.]

Clock dials fixed on both gable ends of a large building are quite typical. These would use huge lengths of lead off work to reach both dials from the clock movement. Which may not necessarily be situated in the center of the building. The lead-off shafts [or pipes] would pass through simple, plain bearings to ensure they rotated in a reasonable straight line. These bearing brackets would be fixed to available timbers and walls to keep costs and complexity to a minimum. Though wooden troughs are sometimes constructed to house the lead-off work. Particularly where the space might also be used for storage.

Note the sturdy construction of all the support brackets and gears. Reliability over decades without maintenance is a vital feature of most public clock installations. Access to the lead-off work is often difficult to impossible with modern safety demands. Rotational "play" or backlash must be avoided between the clock movement and and the dial[s]. Multiple dials would run fast or slow of each other if their was any slack in their respective drives. Such "competition" between various clock dials was a cause for worker irritation when very few of the working classes owned watches. It must be remembered that for several centuries timekeeping was usually provided by public clocks and bells.


The cast brackets of the motionwork are designed to allow dismantling of one set of gears without touching the other pair. This is an important factor where access is often difficult and the security of the heavy, attached clock hands is absolutely vital.

The deep blue-green paint is familiar to Gents' WT made sometime around WW2.

Here the arrangement of all four gears is nicely seen. Only the pair on the right are connected together [as one unit] on their short, offset shaft. The larger of this right hand pair is driven by the input [minute hand] pinion. This is the steel gear just behind the universal/expansion coupling. While the smaller gear of the second pair drives the larger gear fixed to the hour pipe. This motionwork arrangement is common to almost every clock and watch, fitted with two hands, regardless of size.

Usually only 'early' or village church clocks continued with one [hour] hand. At one time it was normal for rural clock owners to have their long case [grandfather] clocks made to order with only one hand. So used were they to reading their one-handed, village, church clock. City dwellers, with their far greater collective wealth, would have enjoyed two handed turret clocks. They would order clocks with two hands despite its greater expense.

The difficulty with one handed clocks was that the hour hand is driven directly. It is very difficult [to impossible] to add a special motionwork to increase the speed to drive a [new] minute hand at 12 times the speed. Not without having serious 'slop' in the movement of the minute hand.

Many early and rural-made, 30 hour grandfather clocks have been converted to have a minute hand to match demand and modern tastes. Often these clock's dials have no minute markers. Usually the dials have only 1/4 hour markings in a ring further towards the dial center. Many antique dealers have profited from having a minute hand fitted. Because they could fool the gullible buyer into believing they were actually buying a much more expensive [and therefore far more desirable] 8-day clock. A glance at the engravings on a brass dial clock will soon show that it was originally fitted with only one [hour] hand and NO motionwork!


WARNING: Those finding themselves with a public clock installation in obvious need of repair should be very aware of the great importance of safety. Particularly where motionwork and the clock hands are concerned. Attempting to dismantle the motionwork [inside the building] could easily release the heavy clock hands. Even if they did not actually fall from the clock tower they might turn suddenly around their axes. The hands will always seek to balance themselves on their shafts and pipes. They may even have built-up torque in the lead-off work which caused the original stoppage.

It is not impossible for rivets to rust away allowing the hand's external counterweights to fall away unnoticed. The clock hands, hidden outside, on the other side of the obscuring dial plate, would then be non-counterbalanced!

If serious rust has set into the minute shaft or hour pipe [through poor material choice or great age] then a dangerous situation could easily arise. Easy access to the outside of the dial and the hands is not normal turret clock practice. Steeple jacks may well be needed to examine the dial, hands and counterweights! Or to bring them down for safety and subsequent repair. Preferably in the workshop of a skilled, experienced [and qualified] turret clock repairer. Mechanics and DIY enthusiasts are likely to make poor and dangerously ignorant clock repairers.

While clock botchers can [and will] ruin any clock they can lay their hands on, public safety is rarely an issue. Public clocks tend to use very large and very heavy components by their very nature. These same components are often raised high above the ground in very public spaces. The results of even a simple mistake could easily be fatal! How could the untrained amateur have any concept [at all] of the very real risks involved?

Just because a WT is a compact movement does not make it any less dangerous in its other parts. The hands on the WT's exposed dials used much the same techniques as all other turret/tower clocks. The hands and dials may even be considerably larger than normal weight driven clocks thanks to the enormous torque generated by the WT movement!

In many cases, though, the WT would be installed in place of an existing, possibly obsolete or badly worn out, weight driven clock. Being so compact and lacking any need for weight shafts, cables and weights made the WT an extremely flexible timekeeping option. It could be and was installed in many inaccessible places like war memorials and chimneys. Where regular maintenance was often all but impossible without the aid of a steeplejack.

ALWAYS SEEK PROFESSIONAL ADVICE WHEN DEALING WITH A PUBLIC CLOCK! LIVES MAY EASILY DEPEND ON YOUR ACTIONS!
                                                                                                                                                                                                                                 
Click on any image for an enlargement.
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