This web page is provided for those who wish to know the full details of how our church clock and carillon work and are maintained in daily use. It is presented in three sections
Church Equipment Handbook – Introduction
As people come and go, knowledge of the increasing number of technical systems and equipment installed or used in the church is lost, and the ability to cope with problems that arise is diminished. This handbook is intended to provide a reference for those who have to operate these equipments and to deal with problems in them.
It is intended that a complete up-to-date printed copy should be kept in a loose-leaf binder in the vestry, and that copies of parts may be kept with the equipment or where they may be most immediately useful. It will contain chapters on separate subsystems, added as they are written, and bearing the date of their last amendment or re-printing. Each chapter should have:-
- A Name, indicating what it does or doesn’t cover;
- A Contact, whoever knows most about it, and generally looks after it, or holds keys, or may be called out to deal with major problems; whether a member of the congregation or a supplier or contractor.
- A Description, with location, brief history, purpose, components and principles of operation.
- One or more Instructions, for routine operation or setting-up or emergency actions. Each instruction should say who it is addressed to, and what they are expected to know already or be capable of doing.
The Church Clock
CONTACT: Malcolm Loveday
In horological terms, this is a flatbed turret clock with three trains, striking the hours and Westminster (or Cambridge) chimes at the quarters on the tower bells. It is connected to a carillon or tune barrel on the floor below, which plays tunes on the bells four times a day. It has a Double Three-Legged Gravity escapement; this was invented and first used in the Great Clock at Westminster (“Big Ben”) by E.B.Denison, later Lord Grimthorpe, who also advised on the design of this clock. The pendulum (compensated??) has a period of 2½ seconds (one side to the other and back = two ticks) so 48 ticks/min.
The clock was made by J Smith & Sons of the Midland Steam Clock Works, Derby.
It was presented by William Anthony Herring, Ironfounder (of Chertsey), and Mary Elizabeth his wife, and was dedicated and set going on 14 October 1892.
“Be ruled by Time, the wisest counsellor of all.”
[The clock it replaced is in the church tower of Eltisley, a village near Papworth Everard on the A428 (was A45) between Cambridge and St.Neots, and is still in use.]
It needs winding twice a week, and has been fitted with power-assisted winding, initiated manually. This is not currently used on the chiming train, as it is quicker to wind it by hand: it has a heavier weight, more purchase and lower gearing. It is enclosed in a wooden case to keep out dirt and so reduce wear.
Unless it is stopped by accident, or has to be reset for Summer Time, it keeps good enough time not to need resetting for several months. A radio-controlled electronic clock is now mounted on the case. This may be used to check the time of the first stroke of the hour.
Several of the illustrations in “The Turret Clock Keeper’s Handbook” by Chris McKay ISBN 0 901180 32 7 are of this tune-barrel (p.12) and of this or a similar clock (pp.9, 11, 31) .
An outline description of the three-legged gravity escapement and its development is at pp A14-A15 in the article by M.S. Loveday and C.G. McKay “BIG BEN” – the design and construction of the Great Clock of the Palace of Westminster, in the book Big Ben – Its Engineering Past and Future published by the Institution of Mechanical Engineers 1981.
WINDING THE CLOCK
This assumes that you have been shown how to do this, but need a reminder, and that you are looking at the clock while you read this.
Look at the weights to see if the clock has already been wound.
Unlock and open fully the RH door of the clock case, and remove the central upright – there is a bolt at the bottom inside, and a piece of wood that turns at the top, only one of these need be undone – then open the LH door fully.
Look at the brass minutes dial to see if the clock is about to strike.
If it is less than 5 minutes to the next quarter, don’t start winding the clock. Wait until after it has chimed and struck. The winding drums need to be able to rotate then. If you are winding at the time, they will not be able to drive the chimes, and the striking may get out of step with the time.
Start with the RH (hours) drum. Turn the dog so that the thin end of the pin points in the direction the drum will turn; the dog will then drop down to engage the steel sprocket wheel. Press Forward on the RH contactor box, and the RH hours weight will be slowly wound up (takes up to 5 minutes).
Meanwhile, lift fully the maintaining weight arm in front of the centre (time) drum, then turn the dog on this one and press Forward on the centre contactor box, the middle (time) weight will be wound up (takes 2½ minutes, about half the RH one).
Both these drums will stop winding when the pulley above the weight lifts the arm of the microswitch above it. When it does this, the dog must be disengaged, to let the drum rotate and drive the clock. Press Reverse on the appropriate contactor, to take the pressure off the dog (which will ratchet and not drive in this direction), then immediately press Stop. Pull the dog out by the pin, and rotate it so that the thin end of the pin points to the shaft, and the pin drops into the shallow grooves in the end of the brass collar.
While the hours and time weights are winding up, fit the handle to the LH (quarters) drum and wind this by hand. Usually this will take about 120 to 140 turns, but there is nothing to stop it going too far, so stop every 20-30 turns or get a helper to see when the weight comes through the floor (about 25 turns to go) and when its pulley is level with those of the other fully-wound weights. When you stop, let the handle back gently so that the pawl does not jar on the ratchet. Stop when each of the other drums finishes winding, to disengage the dogs on it. If you wind fairly briskly, the time drum will finish when you have done about 60-80 turns, and you may just beat the hours drum to the finish.
Take the handle off and put it on the bench in front of the clock case. Make sure both the dogs are disengaged, pulled out and the pins sitting in the grooves. Close the doors and replace the central upright, but do not lock the RH door – it will stick shut.
WHAT TO DO IF THE CLOCK STOPS, OR STRIKES WRONGLY
This assumes that you know how to wind the clock. You may need to go up the tower to the old roof space: can you do this safely? Don’t do it on your own; two heads are better than one, especially if one has an accident.
Try to find out why it has stopped. This has often happened after tower open days (- such as on Black Cherry Fair). Possible reasons are:-
- Something jammed in the weight-shaft, maybe as a result of tidying up the carillon floor. Look for this before moving anything else.
- Are the winding sprockets uncoupled? Were the dogs are left in when last wound, or have they slipped in? (The hour-striking RH one is prone to this).
- Not wound up. Wind it up, time and count how much winding it takes. This can give a clue, if needed, to how long after last winding it stopped.
- If the pendulum has stopped, restart it, by reaching under the clock-frame and giving the pendulum a succession of gentle pushes until you hear the ticks and see the six-legged escapement at the back centre rotating with them. Does it soon stop? Is there something touching or jamming the drive rods that go up from the clock, through the bells, to a four-way gearbox in the roof space, and out to the hour-hand gearboxes behind each of the four dials? Are any of the shafts (especially the North) bent? Is there debris in any of the gears, or between any of the hour-hand counterweights and the recess in the brickwork – the North dial has very little clearance here, only 1/16inch (2mm).
- Has one of the weights been overwound, and come off its pulleys?
- (Most likely when hand-winding the quarter-chimes (left-hand) drum).
- Are the clock hands bent or jammed? Inspect them with binoculars.
- Something else!
The clock mechanism itself is very reliable, external causes are more likely.
If you have found the cause, correct it if you can do so safely and easily, and restart the clock. Contact Malcolm Loveday anyway.
Restarting or Resetting the Clock.
Follow these instructions without taking short-cuts, but without doing anything unnecessary, and all will be well. The main problems are to make sure the dials, quarter-chimes, hour-striking and carillon (in that order) are all working at the proper times.
Go outside, and note the time shown on the dials (which may vary by 2-3 minutes from each other, and from the brass minute dial on the clock, and from the time it strikes the hour).
On the ground floor, hook off all the chimes and carillon to avoid public disturbance.
Switch on the fluorescent light in the clock-case, which plugs into the socket on the East wall to the left of the clock.
Do not touch the carillon or move any of the levers in the clock at random. If you do not know what to do, or cannot follow these instructions, leave it alone and find someone who can.
See separate instructions for re-setting the carillon – do this after resetting the clock.
(Wind up all three clock weights.)
Resetting the Dials. Working at the clock, advance the time shown to the correct time, as necessary. Slowly turn the vertical shaft above the brass minute dial and bevel gears, holding it by the coupling with both hands. It will not turn backwards, and is stiff to turn against the resistance of the dial drives and the friction clutch (??) that the clock drives it through.
As you turn it, it will set off the quarter-chimes and the hour-striking. To avoid the need to reset the quarter-chimes (and possibly the hour-striking) listen for a clonk (“warning”) from the left-hand part of the clock, at about five-and-half minutes before each quarter – the vanes there may whirr, too. Move gently on to the quarter, there will be another clonk,and the left-hand (quarter-chimes) drum will rotate. On the hour, the right-hand (hour-strike) drum will next “warn” then rotate. The carillon will operate after this at its due times. You can move the clock on before the chimes and hour have finished striking, provided you allow them to finish before you get near the point where it “warns” before chiming the next quarter. You may possibly need to wait for the carillon to finish before you reach the hour it is due to play again.
Things to look out for while doing this. Check that the hours are struck when the dial is at 60. If so, there will be no need to reset the chimes. As the hour strikes, count the number of metallic clicks of the spring pawl on the brass wheel at the back right-hand side of the clock, this will tell you the hour that is striking – the first click is immediatelyafter it starts, the clunk at the end does not count. See if this agrees with the hour that the dials are showing. If it doesn’t, the hour-striking will need resetting. Even if it does agree, but is 12 hours out, you may still need to reset it – see below.
Resetting the Quarter-chimes.
If this is not needed, skip this section. (It is seldom necessary, so it is more detailed)
The chimes are set off by four pins on the back of the brass minute dial. These push down (for “warning”) and release (to set off chiming) a lever above the front of the clock frame. Through the upper spindle that they are both fixed to, this raises and drops the upper lever at the back of the clock, which sets off the chiming mechanism . You can set off the chimes manually by briefly twisting this shaft clockwise.
The chimes barrel, which has pegs on it to pull back and release the hammers on the bells, rotates clockwise as seen from the front, and makes a whole turn in two hours. There are five levers to ring four bells, this is because one of them(7) needs to be struck twice so closely that there is not time for a single hammer to be drawn back to strike again, so it has two hammers. Bells struck at the hour are:
2 4 3 7 – 7 3 2 4 – 2 4 3 7 – 7 3 2 4 [or musically D# B C# F# – F# C# D# F# (Bells are in key of E major)].
On the back of the chimes barrel, invisible from the front, there are eight pins, two longer than the others. All these pins lift the upper lever to stop the chimes, acting on the bottom end of the leg fixed to this lever. The spaces between the pins are proportional to the number of chimes at each quarter, so are 18º, 36°, 54º, 72º. The two long pins, as well as doing this, lift and drop the lower lever to set off the hour-striking: this movement gets there through the lower spindle, a lever descending from it to inside the front frame, a sliding bar there, and another pair of levers on a spindle raised above the frame at the right-hand end.
When the chime-barrel has finished the full chimes for the hour, and has set off the striking of the hour, one of the two long pins can be felt ?? under the two levers at the back of the chime-barrel.?? or roughly in the middle of the right-hand upper side of the chime-barrel (72º from the vertical), with no other pin in that quadrant??
You cannot easily see how far the chimes have got from the position of any visible part of the barrel (such as the pawl), as there is no “pointer” to line it up with, and some of its movements are fairly small (18º).
Resetting the Hour-striking (and carillon set-off).
This part of the clock triggers the carillon, making it play at 8am, 1pm, 5pm, and 10pm, so it needs to be set right on a 24-hour basis. Look in the mirror behind the right-hand (hour-striking) part of the clock for a five-spoked brass ratchet wheel with four small studs on the back of it, that lift a square-ended lever on the right, which sets off the carillon when it drops at the end of striking the hour. This wheel rotates anticlockwise as seen in the mirror, as the hours strike, once in 24 hours.
The stud that is midway between two spokes is for 1pm, the one nearest it is for 5pm, the other two are for 10pm and 8am. They are unevenly spaced, the gap corresponds to the number of times the hour-bell is struck.
Work out from this whether it is at am or pm, and which hour will next be struck. If it is in the wrong half of the 24 hours, or you are not sure exactly which hour was struck last, you will have to set off the hour-strike enough times to find out where it is, and to work it round to where it should be – this can take time!.
To do this, grasp the shaft that runs above the clock and is connected to the lever that releases the hour-strike. Twist it anti-clockwise briefly to strike the next hour. Count the number of clicks as above, equal to the hour that is being struck, observe the pins on the back of the brass ratchet-wheel, and whether the carillon-release lever is dropped at the end of the hour-striking. Repeat until you have got it in the right position, ready to strike the real next hour (of 24!) .
Set it going, and finish up.
Restart the clock if necessary by reaching under the clock-frame and giving the pendulum a succession of gentle pushes until you hear the ticks and see the six-legged escapement at the back centre rotating with them. Wait a few minutes to make sure it does not stop again. Rewind whichever spindles need it – you may have used a lot up in resetting the hour-striking. Make sure the winding sprocket dogs are disengaged. Close the case, switch off the fluorescent light at the wall socket.
Now turn your attention to the carillon itself – see separate instructions.
When you have left the tower, lock it, and unhook the clock and carillon hammers at the ground floor.
The “Carillon” (Drum Chime)
CONTACT: Malcolm Loveday.
The “carillon”, “drum chime” or “tune barrel” is like a musical-box that plays tunes on the tower bells. It is on the south side of the first floor of the tower, within a wooden case. Made by J.W. Benson of London, it was given on 27 December 1893 by Frederick Lowten Spinks of Kent in memory of his great-grandfather Daniel Blake who resided for many years in Chertsey and died 2nd June 1796. Tunes are played four times a day after the hour is struck:-
- 8 a.m. We love the place O Lord
- 1 p.m. Home Sweet Home
- 5 p.m. Sicilian Mariners (a Victorian hymn tune)
- 10 p.m. Now the Day is Over.
It was originally weight-driven, but it is now driven directly by an electric motor within the the left-hand side of the case The disconnected original weight is still in the bottom of the shaft at the north-west corner of the tower, the winding drum and the slot in the front of the case are still there, as is the handle for winding the weights up. An illustration on p.12 of “The Turret Clock Keeper’s Handbook” by Chris McKay shows this carillon or tune-barrel before its electrification, with a fly or vanes where the pulley for the motor drive now is.
The clock on the floor above starts the carillon by pulling a wire briefly. This operates one of a pair of microswitches which start and stop the motor, through a contactor or relay. Each time it operates, it plays the tune twice, then shifts the set of trip-levers sideways so that they line up with another set of studs ready to play the next tune. Each trip-lever pulls a hammer back, then lets it fall onto a bell, against a spring which holds it clear of the bell as it sounds. Although there are only eight bells in the tower, there are eleven trip-levers. If a bell is to be struck twice in quick succession there is not time for a single hammer to be pulled back to strike again, so two hammers and trip-levers are provided. The bells operated are, from left to right, 6 1 2 3 4 4 5 5 6 7 8.
DETAILS OF ELECTRICAL OPERATION (see also drawings – to be appended)
Electrical supply is from the fusebox on the carillon floor, near the the stairs: the third fuse or circuit-breaker from the switch (on the right) supplies the carillon. A Pyrotenax cable runs to a circular junction-box inside the case, high on the left. The supply from this goes to a contactor below it, with only one (RESET) button on it. Cables run from the contactor to the two microswitches mounted on a light-green bracket on the right-hand side of the carillon mechanism, and to the motor, which is a ¼ h.p. induction type with in-line reduction gearbox.
The contactor has two functions: as a safety cut-out (hence the RESET button), and as a relay by which the small current carried by the microswitches controls the much heavier current through the motor. The relay is not self-latching; it only ‘makes’ while there is current through the microswitch circuit.
The two microswitches each have three terminals, all six are wired separately back to the contactor, colour-coded Red=common, Green=Normally Open, Black=Normally Closed. They are connected NO to NC in a floating terminal block in the contactor, so that they work like a pair of two-way switches for a domestic landing light. See diagram … When stopped, both switches are in the Normal position. When the clock pulls the wire it lifts the upper microswitch lever briefly, running the motor just long enough for a lower lever to be dropped onto the lower microswitch, which keeps the motor running after the upper microswitch has returned to normal, until the lower lever is lifted again at the end of the operation of the carillon.
DETAILS OF MECHANICAL OPERATION
The motor on the floor inside the left-hand side of the case drives through pulleys and a V-belt a long shaft (A) which goes across above and in front of the mechanism, and has a brass lantern wheel on it near the left-hand end. This engages a large brass gear-wheel, fixed on a lower long shaft (B) which goes across in front of the tune barrel. A steel pinion near the other end of it drives the large gear on the right-hand end of the tune barrel.
The tune-barrel shaft has on its end, outside the right-hand frame, a smaller gear with a pin on its left-hand side, towards the frame. This gear engages with a larger gear above it, which rotates at half the speed of the tune-barrel, and has a knife-edged pin on its right-hand side. This pin lifts a tapered leg fixed below a lever which it lifts off the lower microswitch, to stop the mechanism after the tune has been played twice through.
During operation, the pin on the smaller gear twice lifts the curved lower end of a vertical sliding bar near the back. This bar carries a pawl which engages with one of the eight pins on the left-hand side of the large brass cam-wheel and turns it just after the tune has been played, while the trip-levers are at a blank stretch of the barrel The cam is thus rotated a quarter of a turn every time the carillon operates, and this changes the tune ready for the next time it operates. The cam pushes a follower fixed to the end of the rod on which the trip-levers pivot (the trip-bar), so that they all move together to engage the studs for the next tune. The follower is pushed to the right by the cam three times, then pulled to the left for the fourth change of tune by a flexible wire passing over a small pulley to a weight. This holds the follower against the face of the cam. When the trip-bar is furthest to the left, it plays the 8 a.m. tune, at the positions corresponding to the steps on the cam it plays the other tunes, until in its rightmost position it plays the 10 p.m. tune, “Now the Day is Over”. When the carillon hammers are “barred off”, the friction of the bar on the tails of the trip-levers is considerable, and will prevent the weight moving the trip-bar to the left.
Formerly, the upper shaft A had a large fly or pair of vanes on it, to control the speed at which the weights turned the tune-barrel. A bulge in the left front of the wooden case gave space for the fly to turn. The ratchet wheel that drove the fly fitted onto the squared end of shaft A. On the right-hand side inside the frame this shaft has a small ratchet to prevent reverse rotation, which could seriously damage the trips and barrel. This shaft also has a hole through its right-hand end. A three-legged lever was pinned onto this, with a pin on the longest end which engaged the two stops that can be seen on the end of the lever which now holds down the lower microswitch while running. This lever was formerly lifted by the wire from the clock, performing a similar function mechanically to the starting microswitch and two-way switching, by allowing the barrel to move a little way. When the wire was released the lever was then no longer held up by the knife-edged pin on the larger upper gear-wheel, so that the barrel could run. The smaller parts that were removed are still in the case, in the right-hand front on the floor. The winding handle and the fly are clipped to the outside of the case.
The winding handle is also clipped to the front of the case. The wire from the winding drum went through a slot in the front of the case, across the chamber to a pulley hooked to a traveller on a bar fixed to the floor at the foot of the wall opposite, up through a slot in the floor into the clock-chamber above, to a pulley hooked to a beam on the wall above the ladder to the bell-chamber, then across to one of the pulleys at the head of the weight-shaft. (changes … )
WHAT TO DO IF …
Tunes are played at the wrong times. Most likely due to the clock being upset, and striking the wrong hours. See the chapter on the clock for correction of this.
The wrong tunes are played at the right times. This can occur if there has been a power cut when a tune was to be played. The clock is unaffected, but the carillon will not start or run unless there is power when the clock signals it to play, so it gets ‘out of step’. It is also likely if the clock has been reset. Look at the brass cam to see which tune will be played at the next operation time. If it is not the right one, you will either have to move the cam to the right position by hand (turn it towards you), or to run the carillon until it is in the right position. This takes longer, but you are less likely to get greasy hands or clothes. The carillon should be silenced while this is done, by pulling down the lever on the ground floor. Pull up the wire from the clock briefly, so that the motor starts, then drop it and the motor will continue to run, stopping itself when the drum has rotated and the tune has been played twice.
Two different tunes are played at one time, instead of the same tune twice. The cam has been moved one-eighth of a turn, so that the step in the cam is met between the two turns of the tune-barrel, instead of at the end. Turn the cam by hand, towards you, against the spring which bears on the pins, until it is in the right position (see above).
The power is on, but the motor will not start and there is no noise from the contactor on lifting the wire. There is probably an electrical fault. Check the fusebox, and press RESET on the contactor once only. If it still does not work, contact Malcolm Loveday as above: it needs examination by an electrician.
SOME PAST PROBLEMS
Corrected on 30th June 1990. No action, no noise from contactor, fuse OK.
The contactor makes a fairly hefty thump when it operates, probably this had shaken loose a screw terminal, disconnecting a lead to one of the coils (see diagram … ), so that it did not operate. The screw was found, replaced, and done up tight again. (It would have been better with a shakeproof washer, but none was to hand.)
Corrected in August/September 2000. The same tune (10 p.m. one) was played at all four times. (Hardly anyone noticed!) The thin flexible wire link from the cam- follower to the weight which holds it against the tune-change cam had broken, so that the trip-bar remained in its rightmost position. The hole in the tang of the weight through which the wire was tied and where it broke has sharp edges: the hole that the wire was tied through in the cam-follower has chamfered edges. The wire was replaced with a thicker, stiffer one with an eye with a thimble at one end. This was connected to the weight with a small stainless steel strip shackle. As the hole in the tang of the weight was below the level of the top of the weights, a hole was cut in the topmost weight to allow the shackle to be inserted. At the other end, the wire was led over the pulley, through the hole in the frame, looped through the eye in the cam-follower, and held with two small Jubilee clips. (A thimble could not be fitted, because of the stiffness of the wire; and there is not room to use a shackle. A spare length of this wire and some more flexible wire with an eye in one end have been left in the clock-case.)
The trip-bar bushes may need more frequent lubrication (with clock oil), and the flexible wire should be lubricated where it is bent as it runs over the pulley. How often? what other parts need regular lubrication? Would it be advisable to oil or grease the eye in the cam-follower, to reduce wear on the wire looped through it?
revised and reprinted
© 1990, 2000 David Lambeth and St. Peter’s Church, Chertsey