Gents Pulsynetic Bell Striker C54 description of actions.

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Click on any image for an enlargement.

Having studied the illustrations kindly provided by Anthony Roberts I have reduced the details to the  following: (A fully illustrated, rewrite of my original post will also follow. The original post was far too wordy and unhelpful for those simply seeking advice on returning a Gents C54 Pulsynetic Bell Striker to working order)

It is possible that somebody has arrived here having discovered a similar mechanism in a dark roof space or disused building. You may have found a label and then searched for the very strange name "Pulsynetic" online. Do not scrap the device without seeking further help or advice. If it really cannot be retained in its original installation then sell it on eBay. Where its value to the world will be maximised. A local mixed auction is very unlikely to raise much interest through complete ignorance of the unusual subject matter. While eBay is monitored by the world's active collectors of electrical horological items.

Thirty years ago very few clock collectors who had any interest in electrical-industrial horology. There are now (probably) several thousand enthusiasts around the globe willing to compete for ownership of items from the heyday of master clocks and impulse systems. Some collectors like to discuss their new find or acquisition in online forums with other enthusiasts. Selling on eBay will not unduly increase the price of such artefacts as is sometimes thought. The advice given is just an attempt to keep the devices in this world. Rather than ending up on the world's scrap heaps. As has happened to so much of our industrial, engineering and technical heritage.



A skilled collector will probably restore an item to its (original) former glory and maintain it for future generations to examine and enjoy. They may even study the object carefully and then publish a useful description which is freely available online. Hopefully giving enough advice to keep other bell strikers working in their original situation.   

Note: A bell striker needs a master clock and an hourly impulse timer to work as intended. 
Oh, and a bell, a gong or tubular bell to strike on, for the hours to be heard!

Please refer to the labelled image above to help in recognition of the various components mentioned in the following:

Gents C54 Pulsynetic (early model) Bell Striker sequence of actions:

At rest:

The bell striker mechanism sits motionless with the motor shaft brake applied by its coil spring.

The see-saw control arm is raised by its counterweight and unlatched.

The strike locking detent sits deep in a notch on the count wheel rim.

Since the control arm is raised the microswitch contacts remain open.
No power is flowing in any component.

Hourly Impulse and strike release:

On the hour, a low voltage impulse arrives from the impulse timer. (Gents Contact Timer or Bell Ringer)

The twin electromagnets pull down the control arm against its opposing counterweight.

The control arm drops, at its far end, closing the microswitch contacts.
The relay, in its separate box, is activated and closes its switching contacts.
The arm becomes temporarily latched in the down position. 

Current flows, the motor starts and the brake solenoid is activated, instantly releasing the brake.

Striking:

The bell striking system runs under the power of the electric motor.

The cam rotates every 3 seconds to strike the bell via the long black lever, pull wire and hammer.

The long finger on the camshaft  repeatedly releases the control arm latch via the rearward extension.

Counting:

The count wheel/plate slowly rotates but the intervening 'land' won't allow the locking detent to rise.

The locking detent gently rubs along the rim of the count wheel as it turns.
The length of the 'land' on the slowly rotating circumference of the count wheel dictates how many blows are struck. 

Striking continues until the locking detent is finally allowed to rise with the arrival of the next notch on the count wheel rim.

Release:

The locking detent rises into the notch as the control/switching arm is raised by its counterweight.

The microswitch contacts open and the mains power is switched off by the relay contacts opening.

The motor tries to run on due to rotational momentum.

But, without power, the brake solenoid also switches off.

Its spring instantly reapplies the brake to quickly stop the motor shaft from turning.

At rest again:

The system sits and waits for the next hourly impulse from the remote impulse timer.

Note: The mechanism can only strike the hours in numerical sequence.
The remote contact device supplies only one low voltage DC impulse on the hour to initiate striking.
The bell striker itself counts how many hours to strike using its rotating count wheel/plate.
If there were no notches in the rim of the count wheel the striking would continue, without pause, forever.

Note:

Later examples of Gents C54 Bell Striker use heavy motor switching contacts rather than a microswitch. This is to avoid switching contact burning from the high current demands and even possible arcing from the motor starting and stopping. The microswitch on the example shown here uses a relay to carry out the actual motor and brake switching.

Night/Weekend silencing:

By delaying the hourly impulse from the bell ringer/contact maker for exactly 13 hours the count wheel strike will restart the striking correctly next morning. For example: Allow 8pm to strike in the evening. The next possible correct strike next morning will be at at 9 o'clock.

Of course, any other hours (separated by 13 hours) may be selected. Though these may not be quite so socially acceptable or even useful. For bell striking silencing to take place the contact maker/bell ringer must be stopped from sending its normal hourly impulses. This may easily be arranged by removing contact pins or using a contact masking cam on the 24 hour contact maker (or Gents programmable bell ringer) wheel when strike silencing is desired.

The problem with count wheel/plate striking is that it cannot recover lost hours. If silenced by an absence of starting impulse it can only strike the next hour from the last which it struck. 1,2,3,4,5,6 etc. If you want to change the strike to an earlier hour then you must let it strike "right around the clock" until it gets there. This can take some considerable time! The consequent racket may also confuse or irritate the neighbours! Though you can always silence the bell by temporarily disconnecting the hammer pull wire during Daylight Saving Time adjustments. 

Mechanical clocks moved on from the earlier count plate/count wheel to the rack and snail strike system. This had the advantage that the strike count is controlled by a stepped, snail cam. Which is constantly driven on the hour hand pipe of the clock mechanism. Thus the striking cannot get out of synchronisation with the timekeeping shown on the clock dial.

Conversely, the count wheel strike is controlled by the rotation of its own striking train without any reference to the actual timekeeping being shown on the clock dial. The Gents C54 bell striker had no local timekeeping train available to monitor the time, via a constantly rotating snail. So had to rely on the earlier count wheel (or count plate) strike counting system. Though later, a rather complex device was designed by Gents. Which used two independent, Gents clock slaves to maintain synchronisation between the number of hours being struck and the time shown on the dial. The bell striker was then reduced to a simple electric motor, a speed reduction gearbox and a bell hammer lifting cam.  

WARNING!

Pulsynetic Bell Strikers may have live mains electricity on exposed components! 

TREAT WITH EXTREME CAUTION AND AVOID ALL PHYSICAL CONTACT UNLESS THE MAINS POWER IS SAFELY ISOLATED! 

Count plate and count wheel are interchangeable terms for exactly the same thing. Count plate striking has been in use for well over 500 years in turret clocks. 

My thanks go again to Anthony and Donald for pointing out the correct sequence of operations and for supplying additional information. See the next piece for a lengthy, illustrated description of the Gents C54 Pulsynetic Bell Striker:

Click on any image for an enlargement.

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A Gents C54 Pulsynetic Bell Striker Illustrated and described

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Please remember that all images may be enlarged by clicking on them for a closer view.

A fellow clock enthusiast has kindly sent me some images of his Gents' bell striker with permission to use them on my blog. The following is an attempt to describe the function of each part of the Bell Striker mechanism from examining these images. I base my description on my experience with weight driven clocks which also used count wheel striking. Any errors or omissions are entirely my own and will be corrected as soon as they are discovered.

As is typical of Gent's genius they used electricity to avoid the use of heavy weights normal to almost all clock making practice up until that time. The use of electricity allowed the bell striker to be remarkably compact. Completely avoiding the need for heavy weights to be lowered over a very long fall down through the building which housed the clock. Which would have been the typical requirement for any striking turret clock. Moreover, the strike train usually requires much heavier weights than the going (timekeeping or ticking) train in a clock. The extra weight ensured reliable striking even when a clock and its weight cables, shafts and gears were neglected. (wheels and pinions are the terms used by horologists for large and small gears respectively)

The secret to applying electrical power to any mechanism is to drive it at the fastest end of the gear train. Any reduction in speed greatly multiplies the power (torque) available further down the gear train. Conversely, weight-driven devices usually do all their work at the slow end using massive weights. Then use the vagaries of a long gear train to greatly reduce the power via friction, to almost nothing, at the faster, escapement, or air brake end.

Without falling weights there is no need for a clock winder, minder and oiler. An electrical clock system can be fitted and (almost) forgotten in some very inaccessible places. Allowing the fitting of dials and bells in structures which could never cope with a weight driven system. Examples include slender towers, even chimneys and war memorials. However, this places great demands on the reliability of the mechanisms to avoid periodic breakdown through simple neglect. Inaccessibility has its price.

Gents constantly worked to improve their equipment. Often using very advanced materials for the time. Stainless steels, hard chrome plating and aluminium were certainly not commonplace materials in the heyday of these cutting edge, electromechanical clock systems. Ironically, a simple (and cheap) wooden box to cover these mechanisms would avoid all the falling dirt associated with their usual situations. This is also true of weight-driven clocks of course.

When any clock is asked to strike the hours there are three distinct tasks to be performed: The first is to lift and drop a hammer to strike a suitable bell. The second is to accurately and reliably count out the number of hours to be struck. The third is to start striking exactly on the hour. This is so that the bell will keep the same time as that shown on the clock dial.

Despite their usual size and position, public clock dials are not always easily visible. Particularly in the narrow streets of many older cities. Or when the viewer is separated from the clock by distance or obscuring trees. It is known that the very earliest clocks had no external dial but did have audible striking. The attentive and interested listener pricks up his, or her, ears and counts the number of hammer blows on the bell. Then knows the time, with some confidence, without ever having seen the clock dial.

Here I have labelled the main components of the bell striking mechanism. There are four rotating shafts (arbors or axles) and two long, pivoted levers. There are also two, speed-reducing worms and their matching worm wheels. One large and one smaller one. Plus two small bevel gears used to 'turn the corner' between the cam shaft and the count wheel, worm drive shaft. Note that the mechanism is resting on a trolley which is not part of the device. This trolley is only to facilitate movement of the very heavy mechanism. The painted, black, cast iron baseplate dictates the major dimensions of the C54 Bell striker.

This Gents Pulsynetic C54 Bell Striker both counts the hours and lifts and drops the bell hammer. All driven by quite a small, mains, electric motor. This particular Bell Striker mechanism measures 615mm x 320mm with an overall height of about 280mm. Or roughly 24" x 12.5" x 11" high, in old money. It weighs all of 60kg! Or 132lbs! This weight is mostly due to the heavy, cast iron baseplate. The mechanism shown here is described as 'early' due to the overall use of black paint and design details. Later examples would be painted blue-grey or (later still) even plain, industrial grey. See the bottom of this page for fine examples of later Pulsynetic Bell Strikers.

In the image above, the electric drive motor is on the right. This is the prime mover for all four shafts via the three pairs of gears. The motor is coupled to a long, rotating shaft which runs the length of the striking mechanism. Over to the left (in this view) can be seen the larger worm wheel. This is driven from beneath by a matching worm (a short, coarse-threaded, screwed rod) on the extended motor shaft. The worm and its worm wheel reduce the speed of the motor shaft by an amount dictated by the number of teeth on the worm wheel. The torque provided increases at the same rate as the speed reduction with only a slight loss due to friction. The worm wheel itself drives the cam shaft at right angles to the motor shaft. The cam shaft holds the cam near its centre. There is also a long, latch release detent (finger) fixed alongside it on the cam shaft.

At its remote end, the cam shaft has a small bevel gear fixed to it. This drives a matching bevel gear to turn another worm on the same shaft. This second worm drives the second, smaller, worm wheel. Which drives the short (fourth) shaft. Which also carries the vital strike count wheel.

In addition to the four rotating shafts there are two long, rocking arms: A black steel arm for pulling the bell hammer wire is pivoted just behind the motor. There is also a long, counterbalanced, aluminium, control arm. Which has electrical switching duties and also engages with the count wheel via a detent. (i.e. A steel tongue formed on a bracket fixed to the control arm)

The extended motor shaft continues to the extreme left. Where a spring and solenoid-activated disk brake is fitted. The brake is important because the inertia of the motor cannot be brought to an abrupt halt with a pin and (air brake) fan like a typical weight driven striking clock. If the electric motor were to free-wheel on, until friction eventually brought everything to a halt, this would leave all four shafts at random positions. The random effect might even be cumulative. Leading to all sorts of problems. Without the brake an overrun would occur each time the motor was switched off. Leading to a chaotic and random situation between important components.

The rest positions of the four shafts after striking are not just accidental. The hammer lifting cam must be brought to a definite rotational position after striking. So that it is positioned accurately and ready for the next strike. It is a cardinal rule in clock work that striking starts without any load on a hammer lifting device. This requires that the cam is at its minimum lift position at rest. The system thus has a chance to get up to full speed, before the greatest hammer lifting load falls on the drive system. Maximum torque for greatest lifting power can then be reliably achieved. If the cam was already lifting the bell hammer at start up it might even stall the motor. Or draw excessive current with consequent damage to the motor and its switching contacts.


Here is a picture of the hammer lifting cam and large worm wheel seen from the other side. The cam works against a roller on its underside. Pushing down the long, black bell striking lever to pull on the bell hammer wire.

The bronze bearings for the motor shaft extension are visible on either side of the worm wheel. Each has a grease or oil cap. The worm is hidden behind the cam in this view. The long, upright lever, next to the cam, is the unlocking detent for the sprung latch when it is holding down the control arm.

The motor runs on standard mains electricity at 250Volts 50Hz AC.

It runs at 1425rpm and drives a 72 tooth worm wheel via single start worm:

1425 /72 would provide ~20rpm on the cam shaft. Or one strike every 3 seconds. Which will sound the bell with proper authority and suitable pondus. Perfect!

A faster strike always sounds completely lame. Even worse if a clock fly (fan) is loose on its arbor (axle) and the speed of striking rapidly increases throughout the strike! The friction springs which hold the fly against its shaft on the striking train of the clock should really be adjusted. If only to avoid a strike train runaway as happened with "Big Ben"! (Westminster Clock) However, the Gents' bell striker has no need of an air brake  fan. It has an electromagnetically released , spring-operated brake instead.

Here is the notched strike count wheel (or count plate as they are also known). You will notice that each 'land' between the deep notches on the rim has a number stamped there. Each 'land' is longer than the one before it as it rotates clockwise when seen face on. One o'clock is just one wide notch. These numbers represent the number of strikes of the bell for that hour. This is standard clock practice where count wheel striking is fitted. In a clock a lever tries to fall at each blow of the hammer but rests briefly on the 'land' as the count wheel slowly rotates. When the count wheel turns far enough the next deep notch arrives at the detent. The lever can then drop into the notch and locks the strike system until the next hour. In the case of the Gents Bell Striker the lever lifts into the notch. Which amounts to much the same thing. Since it stops the (electrical) power going to the motor by releasing the microswitch.

Notice the small black bracket and its detent (tongue) which sits deep in the count wheel notch between 4 and 5 o'clock in the image above. This bracket and its detent are fitted to a long pivoted and counterbalanced control arm of bright metal. Probably of lightweight aluminium alloy. Its lightness is to make counterbalancing easier. When the tongue (detent) is sitting in the notch the striking is locked. Not by the tongue itself but by the solenoid operated brake on the extended motor shaft. Which is actuated by the control arm rising away from the motor controlling  microswitch.

Here the count wheel (or count plate) can be seen sitting on its own short shaft with its driving worm wheel. Both are pivoted on a raised extension of the main base casting. To the right of the count wheel in the foreground can be seen two bevel gears. These provide a right-angle drive to a second worm hidden under the worm wheel which drives the count wheel alongside it. A spring is used to avoid damage should the system suffer a mechanical blockage. This spring and its drive pin can be seen through the count wheel spokes. This spring may be to avoid damage to the count wheel rim if the detent does not clear properly. The notch walls are also biased at an angle to help the detent to enter and exit. A jammed condition might occur if the solenoid-activated, motor brake failed. Perhaps allowing the motor to run on for too long. Even causing the locking detent to jam against the side of a notch.

The worm drive bevel gears are well seen in the foreground in this image. The number of teeth on the second worm wheel must be 78. 1+2+3+4 up to 12. Of course the count wheel  is not rotating continuously. It only turns when the hours are being struck and it is being driven by the electric motor. Everything stops and rests in between striking sequences.

On a striking clock a bar would fall onto the outside of a ring fitted to a second wheel in the gear train. This ring would have a single notch. When the bar falls into the notch the striking is brought to an abrupt halt. So a flat-bladed fan is used in most clocks to reduce and steady the gear train speed and the shock of stopping the strike so suddenly. (Though torque is usually very low at the fast end of a clock train) The fan also helps to even out the pauses between each single, hammer blow on the bell. Instead of an air-resistance fan the Gents' unit uses a solenoid operated brake. This brake is on the end of the extended motor shaft. Its normal condition is brake locked on.

Though it is difficult to see from this angle the opposed brake disks are on the right behind the black painted metal shield. When no current is flowing to the solenoid the disks are pressed firmly together by the large coil spring on the left in this image. The disk attached to the solenoid is fixed. So this slows the motor shaft by friction without an abrupt shock to the entire system. The driver motor has already been switched off, as the brake is re-applied by simultaneously cutting power to both the motor and the brake solenoid. The solenoid coil has a measured resistance of 236 Ohms suggesting mains operation. The brake solenoid coil is only energised during striking. It will draw 1 Amp = ~244 Watts.

Here is a view of the drive motor from overhead. This clearly shows the end of the counterweighted control/witching arm near the top of the image. Just to the left of the arm's pivots can be seen two electromagnets. Their purpose is to pull down the control arm when the solenoids are energised briefly on the hour. The latch ensures enough time for the locking detent to clear the count wheel notch and settle safely onto the next 'land.' The motor then continues to turn the count wheel until the next notch on the count wheel rim comes along.

The bell hammer, strike lever's pivot is just alongside. As is that of the control arm.

Here are the two control arm electromagnets. These sit under their armature which is fixed to the control arm. The many copper windings are bandaged and lacquered for extra insulation and protection. The armature is attracted to the poles when electricity is applied on the hour to the two coils. The armature firmly pulls down the control arm against the counterbalancing weight. These electromagnets are only activated by the timed impulse from a remote contact maker on the hour. No electricity flows through these coils at any other time. They have a combined resistance of 33 Ohms. An applied DC voltage of around 33 Volts would draw a current of 1 Amp during the short impulse required to pull down and latch the contacting/strike control arm.

The free end of the control arm has a microswitch fitted just below it. The circuit to the electric drive motor and brake solenoid is switched on by the arm dropping. (And off again by the arm rising free of the microswitch)

The control arm catch is labelled sticking up above the control arm in this view. This catch holds down the control arm on a step cut into it. The brass nut near the end of the control arm holds a square peg which fits the catch step.



An overview image of the cam (right) with its roller underneath, the bevel gears (top left) and the aluminium control arm (left) and its catch. (bottom left)

A long extension on the catch reaches backward and bends sharply to point towards the cam. The long steel 'finger' on the cam shaft is the unlatching detent. This rotates with the cam and pushes the latch free of the control arm peg.

The cam roller is boxed within a strong bracket to provide firm support from both sides. The roller carries the downward force of the snail cam's rotation into the hammer lever and thence to the bell hammer wire. The rolling action avoids excessive friction and wear on the cam during striking.

An adjustment screw in a brass bracket (centre left) limits how high the counterbalanced control arm can rise.

The catch is pivoted at the bottom on a cast tab projecting from the base. There is a flat leaf spring visible resting on the base which provides a return spring for the catch.


Here is a close-up, cropped from a larger original image. It helps to clarify the shape and function of the L-shaped latch. Which I have 'painted' in bright orange with PhotoFiltre image handling software. The latch was rather lost in the smaller image I used above. Once recognised it is much easier to see what is lost in the detail.








Anthony has kindly supplied an image of the latch removed from the mechanism. The latch is even more complex than I had imagined. Its leaf spring lies alongside. Thanks to this new image I believe I can now follow the entire sequence of actions.

Bell striker sequence of operations:

The system sits motionless with the motor shaft brake applied by its spring.
The strike locking detent sits deep in a notch in the count wheel rim.
The aluminium control arm is raised and unlatched.
The microswitch contacts are open. No power is flowing.

On the hour, a low voltage, impulse comes from the impulse timer. (Contact device or programmable bell ringer mechanism?)
The electromagnets pull down the control arm against its opposing counterweight.
The control arm falls, is latched down and closes the electrical contacts in the microswitch.
The microswitch energises a relay in the associated black box. 
The relay takes responsibility for switching the mains electricity to the motor and brake release solenoid.   
Current flows simultaneously to the drive motor and brake solenoid pulling off the brake and starting the motor.
The striking system now runs under the power of the motor.

The large snail cam rotates to lift the bell hammer by depressing the long black lever and pull wire.
The unlatching detent (finger) releases the control arm latch on every revolution.

The count wheel rotates but the intervening 'land' won't allow the arm to rise again despite its counterweight. 
The locking detent rubs gently along the rim of the count wheel. 
Striking continues until the locking detent is finally allowed to rise again with the arrival of the next deep notch in the count wheel rim.

The microswitch is released as the control arm rises with the help of its counterweight.
Power is switched off as the microswitch contacts open and release the relay switching contacts. 
Without power, the motor slows but would run on due to momentum. 
The moment the brake solenoid is switched off its powerful spring re-applies the brake.  
This quickly stops the motor shaft from turning.

The system sits quietly and waits for next hourly impulse from the remote impulse timer. (Contact device or programmable bell ringer) 

This image shows the Pulsynetic name cast proudly into the bell striker's main base plate. It must be remembered that Gents were working at the forefront of electromechanical technology and materials for a great many years. Producing many new inventions with a great number of patents granted. Gents' were the leading manufacturer of electric clock systems of all sizes and degree of complexity and were exported right around the world. They produced movements to drive the largest clock dials of the time. Their skill and reliability in all things is legend.

The main disadvantage of count wheel strike control is maintaining a match between bell and dial.  Unless the count wheel turns then night silencing will interrupt the count wheel from counting the hours in numerical sequence. During night/weekend silencing the clock moves on but not the bell striker! Then, when the strike action is restarted the count wheel will continue from its last struck hour.  Regardless of which hour, that might have been, it will strike the next hour in sequence. By timing the strike silence to exactly 13 hours this problem can be overcome. 

For example: By allowing the system to strike at (say) 8pm before night silencing of the hourly electrical signal. Then only let it start striking again at 9am next day. This could easily be arranged by using a programmable impulse timer or bell ringer from the Gent's range. 

I am indebted to Anthony Roberts for his kindness in supplying the images above and many technical details. Hopefully they may allow the guardian, or owner, or even the discoverer of other bell strikers to make sense of their own mechanism. Thus avoiding it standing idle. Or even worse; being scrapped as unrepairable through wilful ignorance!

Below is an image of a later model of C54 Bell striking machine in wonderful condition. Of a slightly different layout to others shown here. The earlier microswitch seems to have given way to a pair of heavy contacts. The motor shaft brake and other details seem much more complex and robust. Perhaps it is a larger model to strike on a heavier bell? The previously overhanging brake assembly has been considerably modified and brought well inboard on these later models. The counterweight on the rocking arm has also been massively increased in size. Though the latch and its peg are still present. Note the use of a long coil spring on the hammer pull lever to limit any potential damage due to a stuck pull wire.

This image is borrowed from Hans Vrolijk's excellent website: http://www.vrolijk-clocks.nl/page/gent-motor-driven-striking-gear  One of only two C54 bell strikers found in a general Google search.

My only interest in publishing my blog is to share details of these fascinating mechanisms with a wider audience and to make them as easy as possible to find online. Hopefully to avoid their early redundancy. I receive no financial reward for my efforts towards that end. If a single device can be saved from the scrap heap then my countless hours of typing, editing and research will have been worthwhile. Otherwise what is the point of documenting this robust, but gently fading technology?


Here is another fascinating website dealing with a working Gents' system. Now with a cleaned and beautifully restored (even later model) Gents C54 Bell Striker: Note the changed layout compared with the earlier examples above. The count wheel and cam have been moved even closer to the motor and the whole mechanism simplified.

Electric Impulse Clock Systems

Unfortunately Martin's email address bounces and he gives no surname. If Martin would like to get in touch I would be grateful for permission to use his image. Or even to have a larger image to show sharper details.

Anything to help those clambering about on their knees, in a dark and rickety roof space. Who find themselves staring at a begrimed mechanism. They need help to more easily recognise their unexpected find. With luck they will find the Pulsynetic label and start searching for further clues on their computer, smart phone or tablet.

What is the point of a "learned" (charitable status) horological society which does not openly publish all its technical papers online? How is the amateur or professional industrial archaeologist to recognise his exciting finds? How is the auction house peruser to determine historical value from a mere pile of grubby scrap? Isn't it our job to produce a set of "Haynes manuals" for all these fascinating clock systems and their components? Hopefully before it is too late and they are all gone?

Answers on a postcard to chris.b at smilemail.dk  Or leave a comment.

A link follows to a website offering a multitude of images of electric clocks and related mechanisms:
This link leads directly to striking mechanisms:

electricclockarchive.org/ClockGallery:Striking Mechanisms

My thanks go again to Anthony and Donald for pointing out the more likely sequence of operations of the Gents' C54 bell striker. My original description required a very long impulse to hold down the control arm via the electromagnets. Their alternative (and much more sensible) suggestions were for a short timing impulse on the hour to re-latch the control arm. The latching ensures that the notch can be rotated clear of the detent without the need for an extended timing impulse. The latch is then released automatically by the next rotation of long "finger" on the camshaft during striking. 

Anthony must also be thanked for kindly providing these excellent images. Any errors and  failure to understand the exact sequence of actions of the bell strikers are entirely my own. 

Click on any image for an enlargement.

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Motorised WT on eBay

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GENTS PULSYNETIC WAITING TRAIN MOVEMENT & MASTER CLOCK | eBay 

This is for A GENTS PULSYNETIC TURRET CLOCK WAITING TRAIN with the electric MASTER CLOCK that it was connected to.

It was installed in a very low roof space in ICI BILLINGHAM, the master clock has a serial number of 2540, matching on label, case and pendulum, the label looks like it was installed 10-2 27. 

The waiting train was modified at some time, looks to be a factory change,(although not sure who did it) by the removal of the pendulum weight and the hip-toggle and the addition of a 240 drive motor with linkages connected to the pendulum staff which drives it backwards and forwards, then idles until it receives the impulse from the master clock every 30 sec then goes again.

The master and the waiting train were installed and removed together and both are in working order. The dial on the master is peeling, it has on it PULSYNETIC & ELECTRIC, so it will need restoration. There are no dials with it as they were left on the building until it was knocked down.

Quite an early Gents' C40A Waiting Train movement. One which has been stripped of its pendulum bob, very large drive electromagnets, their controlling Hipp Toggle and contact assembly.

An interesting (possibly unique) conversion to motor drive of the pendulum rod. It all looks very professionally done. Strongly suggesting a Gents' factory modification. Arguably worth keeping in its original condition for historical reasons.

The WT mechanism still performs perfectly normally. The pendulum driving the ratchet wheel, via the drive pawl. Until the worm drive is paused by the D-shaped pin lifting the pawl out of the ratchet wheel teeth.  

Then at the precise, half-minute the signal comes from the master clock. Releasing the drive pawl to start driving the worm and wormwheel again. To continue showing the time on the exterior dials as normal. The pause is much too short to be seen by a distant watcher of the clock dials.

The electric motor has a worm reduction to a low speed output shaft. Presumably turning at somewhere around 36 rpm to match the usual period of the WT pendulum. (note: Will confirm this figure in practice) The output shaft is fitted with a crank which drives the connecting rod to physically push and pull the pendulum rod. Both ends of the connecting rod are fitted with ball bearings for long life. 

The reason behind the conversion to electric motor drive? Possibly to avoid unwanted noise. Perhaps induced by the stresses of a violent pendulum impulse on a weak roof structure. Perhaps there was simply insufficient room for the pendulum to swing below the WT movement? 

Later discussion by the experts on a clock forum suggests that there was no clearance for a pendulum in the original roof installation. The motor also provided a very quiet drive compared with the mechanical impulsing of a normal WT pendulum.

The bevel gearing is supported on a very substantial, fabricated, right-angle bracket. The hammer marks suggest a bent piece of thick, strip metal. The bevel gears drive a vertical output shaft with expansion-universal joint at one revolution per hour. This drives the clock hands on the external dials via lead-off rods and further bevel gearing. A hand setting dial has been incorporated just below the forked, universal joint. A pointer is attached to the support bracket.

It is rather unfortunate that the seller has chosen to use a white background for their auction photographs. Experience shows that this is one of the worst possible, plain backgrounds for technical photography. The camera is confused by the bright background. This results in massively reduces brightness, contrast and visible detail in the actual object being photographed. I have done my best to rectify the situation in PhotoFiltre. Though not with any particular success.

It could have been (much) worse. The object might have been photographed in front of a busy background. Or, even worse, against a window flooded with daylight.

Matt, neutral colours like beige to light brown work well. Flat, sheet materials like ordinary hardboard or even more ordinary packaging cardboard are good. These make excellent backgrounds for photographing objects like these. The further behind the object they are placed, the better. Because they will be thrown out of sharp focus. Though these background boards will obviously need to be made much larger if placed any great distance behind the subject.

This rather unique WT sold for £785. 

Click on any image for an enlargement.

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A Conspectus of Gents' Clock Products

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Colin Reynolds, the author, worked for Gents for many years and is an expert on its history, archives and products.

At 8.25" x 11.5" [208 x 292mm] with soft covers and 239 pages, this book is literally packed with many completely unique B&W illustrations and historical photographs. Copyright precludes my posting example images here. Though the cover will give an indication of what to expect.

This book is an absolute 'must have' for any electric clock collector. Or horological enthusiast's library. It is meant to be read, studied and enjoyed in all its detail. Not as some "arty" colourful, coffee table decoration. Usually to be left out, in a vain attempt to impress the horologically or technically unwashed. With huge, colour images and cursory captions.

Colin Reynolds descriptive detail, of the Gent timekeeping products and their evolution, is mind boggling. Fascinating from start to finish. The author has access to a unique collection of original material. His descriptive skills are such that any interested enthusiast can follow the "workings" and evolution of any particular item under discussion. Without having seen this book no Gents' admirer has a clue to the enormous range of items manufactured. Who would ever have believed how many different slave mechanisms and cases were produced?

Gents must have enjoyed many mechanical and electrical geniuses in its workforce during its long manufacturing period. From the late 1800s to the late 1900s represents 100 years of excellence. Striving to provide a huge number of items which fulfilled a particular need. Always built to the highest possible standards at affordable prices for the world of commerce, industry, the church, local and national government. They even provided timekeeping to the sea faring. Constant reiteration and improvement helped to provide a consistently better product. With even greater reliability and longer life.

In the end it was rapidly changing lifestyles and new technology which finally brought an end to Gents domination of electro-mechanical timekeeping. The microchip was cheap enough to dominate our lives in other, countless, unforeseen ways.

Gents' timekeeping products are now avidly sought and collected by admirers right around the world. Where complete impulse time systems, in all their complexity, from master clock to striking, are established with beautifully restored examples. Many of which only became available through demolition of a nation's industrial heritage. Or massive redundancy to the advancing tide of cheap, computer technology.

Colin Reynold's amazingly affordable work is a unique history of the cutting edge of commercial, electromechanical timekeeping from the first tentative steps. Gents' early designers should really be household names in Britain such was their importance to people's lives. Gents' remarkable insights and technical brilliance placed them in so many different environments that the technology itself often went completely unnoticed. From schools, to hospitals, to factories and church they kept many generations uniformly informed of the time with remarkable accuracy and reliability. It is a shame that their remarkable inventions and inventors remain largely unknown outside narrow, horological circles. While their main competitor, Hope-Jones, of Synchronome fame, was the master of self-publicity.

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A Gents' WT installation at Terry's Chocolate Factory.

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The following images are all gratefully credited to Matt Allen. A skilled photographer who likes to record Britain's dying, industrial heritage. His images beautifully capture the melancholy atmosphere of the empty factories and workshops of our once-great, household names.

By sheer luck I found his series on the Terry's Chocolate Factory WT installation. He has very kindly allowed me to reproduce his images here.

The WT installation itself faced serious difficulties. The four 8' dials on the tower had an enormous water tank immediately behind them. Meaning that conventional lead off work direct from the movement was impossible.  

The solution was to drive each dial motionwork via chains. The WT movement was housed below the water tank. The lead off work drives the dial chains via sprockets. The motionwork behind the dials takes its power from the WT via the chains.

Judging by the black painted, slender main casting, this WT movement looks like a fairly early C40C. Providing ample power to drive the hands of the four 8' dials. I still have no certain way of identifying larger WT movements. Usually the worm wheel, bevel wheels and time setting dial are larger than the next model down in the series. Here is a link to a list of dials and WT movements: It seems a C40B would have been ample but this one looks rather larger to me. (Later note: Gents' literature claims a C40B at this installation) Later information suggests a C40C. The shoulders meet in a straight line instead of sloping like a C40B.

Dial size against required WT movement size:

The movement is housed in a protective, galvanised steel shelter. The original, cast, main pendulum-drive, contact, steady bars have been replaced with the later pressed design. Just a routine update due to wear on the originals?

The horizontal (rusty) white painted tube on the right is part of the dial lead-off work.

The controlling, Pulsynetic master clock is dated 1930. A vandal has broken the case glass and stolen the pilot dial. The clips may still be seen on either side near the top inside the door. This Pulsynetic master clock was once a beautiful, early example of the Pulsynetic type. Having decorative mouldings at the top and bottom of the case.

The electromechanical movement of the Pulsynetic master clock evolved only in detail over time. Only an expert would be able to identify each model and suggest a date. (I do not remotely count myself as an expert)

The Pulsynetic master clock had an enviable reputation for reliability and long life. All thanks to its design, construction and advanced material choices.

Another view of the rear of one dial showing the Terry's name proudly displayed on the opal glass. An early form of illuminated advertising? Those reading the time would inevitable recognise the meaning of the "Terry" lettering.

Mr Allen's photography nicely captures the light and atmosphere of the tower.

The chain-driven motionwork is housed in the protective metal case behind each dial.

Part of the original Gents' timekeeping installation.

There are the unmistakeable signs of a Pulsynetic master clock having been removed.(The Pulsynetic master clock has a uniquely heavy, cast, triangular hanging bracket at the top) Plus two distinctive cross-brace boards clearly visible as highlights on the wall.

A variety of Gents' impulse timekeeping components remain. The trickle power supply for a battery bank is still present at top left. Top right looks like a low battery charge warning bell. There may also be components here to control the lighting of the opal glass dials at night. The larger case at the bottom may once have held an adjustable programmer. (Bell ringers and factory siren timers were once commonplace)

A link to a website containing illustrations of many original Gents' timekeeping components:

http://pulsynetic.eu/power-supply/

The WT support tower and access stairs.

Note the careful triangulation to ensure rigidity of the structure. This would help timekeeping when the heavy pendulum was impulsed by the drive electromagnets.
Not that timekeeping was critical with the WT thanks to the controlling master clock. A sturdy platform would help to reduce the energy losses to the pendulum. Thereby giving a far greater reserve of driving power for difficult weather conditions. (Ice, wind and snow. Or even flocks of birds settling on the hands)

The damaged master clock resides forlornly in the case behind the tower.

Another, closer, view of the Pulsynetic master clock.

The darkness of the wood and close grain  might suggest mahogany or rosewood. Which has been perhaps 'ebonized' by the factory. I doubt the age and situation would have affected the colour of the inside of the case. It is a most attractive finish which I have not seen in later examples. Could this finish have anything to do with representing dark chocolate? It is not impossible.

Note the original Gents' date label at top left inside the case. A valuable addition to any master clock to provide an accurate date of manufacture.

Do not be fooled  by the dangling electrical flex. These clocks should never be connected direct to the mains! Low voltage DC (depending on the number of series connected dials or equipment) is their requirement. The time circuit is always set to 0.22Amps. Not to some arbitrary DC voltage.

For those who would like to enjoy many more, original images of the Terry factory here is a direct link to Mr Allen's Flickr set:

 Terry of York clock tower

I am most grateful that Mr Allen has allowed me to share his images here. Copyright remains with Mr Allen.

It is believed that this C40C WT movement was stolen. Leading to a national appeal for a replacement. The factory building has since been developed into luxury flats/apartments.

Click on any image for an enlargement.

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Original Gents' WT Drawings

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I found these drawings on my hard drive. No recollection of where they originated. These images have been downsized and their contrast boosted to suit the blog format.


I do have a set of full size drawings but they are far too large to scan easily. I now recommend that large drawings be laid out on the floor and photographed with a common digital camera. Possibly from a stepladder to avoid distortion. Then the resulting camera images "improved" and/or resized in free, digital image handling software. I use PhotoFiltre.

 

Click on any image for an enlargement

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Photobucket WT album!

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While running a thorough Google search for <pulsynetic> I was delighted to find the following album in Photobucket:

http://s626.photobucket.com/albums/tt344/jjjjsmith317/Lafayette%20IN%20Gents%20Pulsynetic%20Clock%20movement/

A C40B(?) Waiting train installation and beautifully photographed! This WT  resides in Lafayette, Indiana in the USA. I finally found it on Google Earth next to the Shell gas station.

The clock dials on their own cupola. Sitting on a lantern on the roof a commercial building. The WT lives right up in there with leading-off rods going straight to the motionwork behind each of the dials. The opal glass and attractive cast iron dials are no doubt backlit at night. One wonders how accessible the movement is to visitors. The roof looks as if it is covered in shingles. 

A beautifully sharp image of the WT movement! Probably quite early judging from the black finish on rather slender castings. Later WT movements look relatively massive and robust in comparison.

The lacquered brass parts and electromagnets are all early. The WT technique has obviously been standardised here. Though there are detail differences in the design of many of the parts. The cranked, Hipp toggle damper hangs unused just above the rocking armature to the left of the drive electromagnets.

The hand setting dial is engraved with the original patents. Surely another early detail? Later dials just have "Pulsynetic". There is a strangely later feature in the contact steady bars being pressed rather than cast. They have also had to be heavily bent upwards to reach the Hipp toggle. Perhaps a replacement? The lack of adjustment in the base may have needed this degree of bending. Though the Hipp toggle does look rather short.

The supporting brackets for some of the parts have no slots for adjustment. The Hipp toggle and contact supports were provided with slots in later WT movements.

A close up of the large, pendulum drive electromagnets. They look quite similar to my own coils except for the brown colour and lack of thick wax. They would have been subject to bright sunshine for decades. Which may have bleached the green. My Synchronome has exactly the same bleaching problem. The rocking armature and pendulum impulse pallet are well seen here. Note the oiler on top of the cast brass(or bronze) armature bearing. The neat little dial pointer is present just below the dial. This would be used for setting the clock hands to time. Useful for summer and winter time changes.

The usual WT detail is rather more slender than I am used to seeing on later WTs. Not exactly conclusive but perhaps suggesting the 1920s?  The photographer has done a great job of catching all the detail despite the potential for glare from the dials in the background. There is no hand setting crank on the ratchet/worm shaft. It may have been lost over the years. I find it exceedingly useful for re-setting the time. 

 

Cast dial centre, 12:1 motionwork and sturdy expansion coupling with leading-off rod going back to the WT off the left side of the picture. The heavy steel frame seems like overkill but may be supporting the iron dial frame against wind loading.

 

Detail seen through the WT's cast frame showing modern wiring. Perhaps a replacement power supply to match modern wiring codes and practice? Two very different transformers are present.I was trying to make the orange 'hats' into diodes. The transformers may actually be related to the lighting system for the translucent dials.

The two hex heads on the right of the picture are the bolts holding the lower pendulum rod and attached bob to the upper section. Separation here made transport and movement for maintenance of the WT movement much easier. The bob being very heavy and unable to be removed easily at the top. Though the sealed bearing support cases can be unbolted and lifted away. This may seriously risk the safety of the upper components attached to the pendulum rod. There was always the problem of the slot in the support bench. The gathering pallet and Hipp toggle would not pass through the slot if the pendulum was detached at the top. By placing a suitable support under the bob the two bolts can be easily undone. Leaving the relatively light upper section to hang freely from its pivot bearings.

A serious amount of metalwork supporting another set of motionwork. The slotted expansion/universal coupling is in the foreground. This would allow for variations in alignment between the WT movement and dial. The leading off rods expand and contract with changing temperature. So the slots in the couplings allow for this too. These couplings are standard features on most turret clocks. They allow for considerable building movement without binding. Many leading off systems are far longer than in this very compact WT installation.

All of these images can now be credited to JJ Smith of Smith's Bell and Clock: http://www.belltowerinstall.com/

I am grateful to Mr Smith for allowing me to share these excellent images.

Click on any image for an enlargement.

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Another WT on YouTube

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While searching for "Pulsynetic" I found another YouTube video of a larger WT. Possibly a C40B.

It follows the same practice as the smaller C40A but is scaled up to drive and control the hands of larger dials. The top of the cast main frame is arched with vertical members on each side. Making it an attractive and balanced design. The Hipp toggle damper now rises from the armature pivot casting. The contact assembly has pressed steady bars from the post war period. While the finish is the earlier black with lacquered brasswork. The time setting dial is present and much larger than those of the C40As. The drive electromagnets look like bare, enamelled copper wire. The video poster suggests it is running on 20VDC. I thought I had seen a table somewhere showing 30V for the B model. It may be a false memory.




It is a great shame that the video background is so busy. But much worse, the camera is being blinded by the glare from the windows behind the WT. One couldn't ask for more difficult filming conditions! The video claims to be 720p HD but sadly it doesn't look it for the reasons given above.

This is not petty criticism for its own sake. Nor some peculiar artistic snobbery on my part. I simply wish to be able to examine this very rare movement in much greater detail. To make valid comparisons with my own movement and all the other material available online and in print.

A published video is not just moving pictures. It is a unique historical record of a piece of technology, in action, on a certain date. Making a visual recording bears a certain amount of responsibility to future study. And yes, I do know that my own efforts are hardly inspiring. Nor do they set the pinnacle of creative video making. That said, they do show all the details reasonably sharply given my limited skills, lack of practice and rather humble equipment. So that a later researcher can identify exactly how the item works and the methods used.

This is not some wishful thinking on my part. Committing a video or photograph to the internet will probably provide an indelible record far into the future. When the item has been lost to the ravages of time, the video or photograph will be the only remaining record of a unique device. One can never tell how such information will be used in the distant future. Students of the future may trawl their own internet like historians and archaeologists search papers, church records and libraries today.

The irony is that future historians may well be far more interested in the background activities and clothing than the WT. Perhaps they will have the skills to 3D print any object which ever existed. Though they may need our help to do so. By our providing enough detail for their advanced technology to maximise our efforts.

Today, we can automatically improve our digital photographs. This, only a few short years after its invention. Tomorrow's technology may be able to rebuild literally anything from scratch. All at relatively low cost.

Perhaps fully realistic moving holograms will be more desirable and collect less dust? A future horologist may easily have a fully lifelike C40B WT clonking away in his study. One which he can walk through as he crosses the room. He may even smile to himself as he walks around it. Fully aware that it does not exist in reality. Happy to pretend that it does. As some private joke.

Few can predict the future. The absence of obvious time travellers could suggest it is truly impossible. Or that there are no time travellers willing to reveal themselves. It may be simply because man ceases to exist. Only a year, or three, into our own future. Some unseen catastrophe involving a crashing asteroid, global thermonuclear war or an incurable pandemic may cut short human progress away from his ignorance, superstition, greed and savagery.

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