GB2383144A

GB2383144A - Automatic regulation of pendulum clocks

Info

Publication number: GB2383144A
Application number: GB0129930A
Authority: GB
Inventors: Robert Alan Youngs
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-12-14
Filing date: 2001-12-14
Publication date: 2003-06-18
Anticipated expiration: 2021-12-14
Also published as: GB2383144B; GB0129930D0

Abstract

A pendulum clock auto-regulation device and a method for automatically regulating a pendulum clock comprises means for monitoring the beat rate of the pendulum 14, means for comparing the beat rate with an independent time base, and means for adjusting the beat rate based on the comparison. An adjustable infrared detection unit 16 outputs a beam which is reflected from the surface of the pendulum to a detector, which sends a signal to a control unit (26, Fig 3) which has a detection circuit (28), comparing circuit (30) and energisation circuit (32), and which receives a signal (34) from an independent time base such as a fixed crystal oscillator, GPS satellite signal and/or mains electricity supply. A solenoid actuator device (36, Fig 1), 40 adjusts the pendulum accordingly by truncating its arc of swing. The method for regulating a pendulum clock includes the steps of positioning the device adjacent the pendulum, setting the clock to run slow and truncating the arc of swing until the beat is synchronised with the independent time base.

Description

A DEVICE AND METHOD FOR THE AUTOMATIC REGULATION OF A PENDULUM CLOCK This invention relates to a device and method for the automatic regulation of pendulum clocks.

It is known that a pendulum clock, which is herein defined as being any clock having a pendulum and which includes turret clocks, can be automatically wound.

This has dispensed with the need for a dedicated person to wind the clock, but has not dispensed with the need for a dedicated person to set the clock.

A pendulum beat rate will, in reality, vary based on ambient factors, such as temperature, draughts, barometric pressure, moisture and humidity, and these factors influence the clock in different ways dependent on, for example, the type of clock, the escapement mechanism used and the location of the clock.

Methods for automatically regulating pendulum clocks have been tried.

However, these have been developed for use with certain kinds of pendulum clock having specific escapement mechanisms and are unable to be used on all types of pendulum clocks.

The present invention seeks to overcome this problem.

According to a first aspect of the present invention, there is provided a pendulum clock auto-regulation device for automatically regulating a pendulum clock of the kind as hereinbefore defined, the device comprising means for monitoring the beat rate of the pendulum, means for comparing the beat rate with an independent time base, and means for adjusting the beat rate based on the comparison.

Preferable and/or optional features of the first aspect of the present invention are set forth in claims 2 to 12, inclusive.

According to a second aspect of the present invention, there is provided a method for automatically regulating a pendulum clock of the kind hereinbefore defined by using a pendulum clock auto-regulation device in accordance with the first aspect of the present invention, the method comprising the steps of: a) suitably positioning the device adjacent to a pendulum of a pendulum clock, and b) setting the said clock to run slow.

A preferred feature of the second aspect of the present invention is set forth in claim 14.

According to a third aspect of the present invention, there is provided a method for automatically regulating a pendulum clock of the kind hereinbefore defined, the method comprising the steps of : a) setting the clock to run slow, b) comparing the beat rate of the pendulum with an independent time base, and c) truncating the arc described by the normal swing of the pendulum until the beat rate of the pendulum is synchronised or substantially synchronised with the independent time base.

A preferred feature of the second aspect of the present invention is set forth in claim 16.

The present invention will now be described, by way of example, with reference to the accompanying drawings, wherein: Figure 1 shows a diagrammatic side view of one embodiment of a pendulum clock auto-regulation device in accordance with the first aspect of the present invention; Figure 2 shows a front view of the device shown in Figure 1;

Figure 3 is a circuit diagram of a control unit of the device; Figure 4 is a wave-form diagram of signals in the control unit; Figure 5 shows the device in use in a first condition; Figure 6 shows the device in use in a second condition; Figure 7 is a sectional side view of a second embodiment of a pendulum clock auto-regulation device in accordance with the first aspect of the present invention; Figure 8 is a diagrammatic side view of a third embodiment of a pendulum clock auto-regulation device in accordance with the first aspect of the present invention; Figure 9 is an end view of the device shown in Figure 8; Figure 10 is a view similar to Figure 8 showing the device in a second condition, and Figure 11 is a view similar to Figure 9 showing the device in the second condition.

Referring firstly to Figures 1 to 6, an automatic regulation device 10 for a pendulum clock of the kind hereinbefore defined comprises a housing 12, means for monitoring the beat rate of a pendulum 14, shown in Figures 5 and 6, means for comparing the beat rate of the pendulum 14 with an independent time base signal 34, referenced in Figure 3, and means for adjusting the beat rate based on the comparison.

The monitoring means comprises an adjustable infra-red detection unit 16

which includes an infra-red beam emitter 18, an infra-red beam detector 20 and a . surface 22 which is on the shaft 24 of the pendulum 14 (see Figures 5 and 6) and which is able to reflect the infra-red beam emitted by the emitter 18 when incident thereon.

The infra-red detection unit 16 can output a signal to the comparing means which comprises a control unit 26 (shown in Figure 3) having a detection circuit 28, a comparing circuit 30 and an energisation circuit 32, and which receives the signal 34 from the independent time base.

The independent time base is a precision time source, such as a fixed crystal oscillator, the Rugby Time Signal service, a GPS satellite signal, and/or the mains electricity supply.

The adjusting means comprises a solenoid actuator device 36 which has an armature 38 received coaxially within a bore (not shown in Figure 1) around at least

part of which is formed a solenoid coil (not shown in Figure 1). Since this type of device 36 is well-known, further details will be omitted.

A buffer element 40 is positioned on the end of the armature 38 adjacent to the pendulum 14, and the solenoid coil of the solenoid actuator device 36 is connected to the energisation circuit 32 of the control unit 26.

The infra-red detection unit 16 and the solenoid actuator device 36 are

mounted independently of each other in the housing 12 so that the detection unit 16 '" can emit and receive its infra-red beam without hindrance from the housing 12 and so that the buffer element 40 can move towards and away from the housing 12 without interference therefrom.

The control unit 26 in this case is mounted spaced from the housing 12, but may be mounted within the housing 12.

The housing 12 has one or more mounting elements 42 to enable the housing 12 to be fixed at a suitable position adjacent to the pendulum 14.

In use, the housing 12 is positioned, via the mounting elements 42, on a suitable surface (not shown) adjacent to the pendulum 14 so that the buffer element 40 can contact the pendulum 14, during at least part of the swing of the pendulum 14, in a direction which is normal or substantially normal to the longitudinal extent of the pendulum 14. Typically, to obtain optimum performance, the housing 12 is located at

a position which is equivalent to a quarter to a third of the distance from the point of swing of the pendulum 14.

If the surface of the pendulum 14 adjacent to the housing 12 is not suitably reflective, then a reflective surface can be mechanically attached, by adhesive for example, to act as the infra-red reflective surface 22.

The angle a of the infra-red beam emitted by the infra-red beam emitter 18 is then adjusted to be incident on the reflective surface 22, as shown in Figures 5 and 6.

This angle is also set such that the infra-red beam can only be detected by the infrared beam detector 20 through a small sector of the arc of the swing of the pendulum 14. The sector typically equates to a range of 5 millimetres (mm) to 25 mm of swing and is conveniently the end portion of the arc nearest to the housing 12.

The armature 38 of the solenoid actuator device 36 is in a retracted state, as shown in Figure 5 with the pendulum 14 at one extreme of its normal swing, and as such there is no or substantially no contact between the buffer element 40 and the pendulum 14.

The escapement mechanism of the clock, of which the pendulum 14 forms a part, is then set to run slow. The amount by which the clock should be set to run slow will vary from clock to clock. If the clock keeps time well, then the general provision is that the clock is set to run slow by a predetermined amount. This can be 10 seconds. If, however, the clock is erratic at keeping time, then the maximum amount

of gain over a given period is determined and the clock is set to run slow by this amount. This should ensure that the beat rate of the pendulum 14 never exceeds the beat rate of the independent time base.

As the pendulum 14, during its swing, approaches the housing 12, the infrared beam becomes directly incident on the reflective surface 22 and, as the pendulum 14 travels through the aforementioned sector, the reflected infra-red beam is detected by the detector 20. Over a period of time, this enables a beat rate of the pendulum 14 to be electronically determined by the detection circuit 28 of the control unit 26 and output as a signal PB, shown in Figure 4, to the comparing circuit 30.

The comparing circuit 30 utilises a window pulse signal WP as a means of initiating a comparison between the pendulum beat rate signal PB and the beat rate IT of the independent time base signal 34. The window pulse signal WP has an ON period of typically 5 nano-seconds and its rising edge is synchronised with that of the pendulum beat rate signal PB.

During the ON period of the window pulse signal WP, the comparing circuit 30 monitors whether the pendulum beat rate PB coincides with the rising edge of the beat rate IT. Since the clock has been deliberately set to run slightly slow, the window pulse signal WP will inevitably move or'creep'over time relative to the beat rate IT. If they do not coincide, no action is taken. When, however, they do coincide, for example as shown at A in Figure 4, then an appropriate signal is output by the comparing circuit 30 to the energisation circuit 32.

When the energisation circuit 32 receives the appropriate signal from the comparing circuit 30, the energisation circuit 32 energises the solenoid coil of the solenoid actuator device 36 which causes the armature 38 to extend. This has the effect of moving the buffer element 40 to a position at which it will make contact or engage with the pendulum 14 during part of its swing. The energisation is such that the arc described by the movement of the pendulum 14 is effectively truncated.

This truncation results in the pendulum beat rate increasing, and thus the clock speeding up.

The truncation is a relatively gradual arresting of the movement of the pendulum 14, before the end of the pendulum's arc is reached, and the application of an equal and opposite accelerating force. The size or magnitude of the retarding and accelerating force exerted by the buffer element 40 is dependent on the magnitude of the current applied to the solenoid coil, and this can be set dependent on the characteristics of the clock in question.

Once the comparing circuit 30 determines that, during the ON period of the window pulse signal WP, the pendulum beat rate signal PB no longer coincides with the beat rate IT of the independent time base, for example as shown at B in Figure 4, the energisation circuit 32 halts the energisation of the solenoid coil which enables the armature 38 to be freely and fully pushed back out of the way by the restored normal swing of the pendulum 14.

The ON period of the pendulum beat rate signal PB, which is effectively set by the angle a of incidence of the infra-red beam on the pendulum 14, is important since it provides the timing cycle duration of the energisation of the solenoid coil and consequently the duration of the retarding and accelerating force exerted by the buffer element 40. It is important that the energisation of the solenoid coil is not altered after the application of the retarding force and before the application of the accelerating force, as this can lead to undesirable effects.

In a second embodiment as shown in Figure 7, the monitoring means and the adjusting means are incorporated as a single element within the housing 12'. In this embodiment, the infra-red detection unit 16'monitors the movement of the pendulum 14 through the movement of the buffer element 40'at the end of the armature 38'of the solenoid actuator device 36'. As such, the infra-red emitter 18'and detector 20' are directly opposed across the armature bore 42 in the housing 12'.

The solenoid coil 44 is in a permanently energised state which urges the armature 38'against a stop 46 in the bore 42 and holds the buffer element 40'at a position by which it will contact the pendulum 14 during a part of each swing.

The energisation of the solenoid coil 44 is just sufficient to urge the armature 38'against the stop 46. As the pendulum 14 contacts the buffer element 40', the force of the pendulum 14 urges the armature 38'along the bore 42 of the housing 12', causing the end of the armature 38'opposite the buffer element 40'to interrupt the

infra-red beam emitted by the infra-red emitter 18'and detected by the infra-red detector 20'.

In a similar fashion to the first embodiment, the housing 12'is positioned so that the infra-red beam is only interrupted through a small sector of the arc of the swing of the pendulum 14. The sector typically equates to a range of 5 millimetres (mm) to 25 mm of swing and is the end portion of the arc nearest to the housing 12'.

Over a period of time, the interruption of the infra-red beam by the armature 38'enables the beat rate of the pendulum 14 to be electronically determined by the detection circuit 28 of the control unit 26 and output as the signal PB to the comparing circuit 30.

If it is determined that the clock is running slowly, the comparing circuit 30 outputs an appropriate signal to the energisation circuit 32 whereby the energisation of the solenoid coil 44 is increased. This has the effect of urging the armature 38' with greater force against the stop 46 and thereby truncating the arc of the pendulum 14 as described above.

In a third embodiment as shown in Figures 8 to 11, the armature 38"of the solenoid actuator device 36"is mechanically linked to an arm element 48, which is generally dog-legged shape and which is mounted for angular displacement about a pivot point P. The buffer element 40"is at one end of the arm element 48 and the pivot point P is positioned so that the arm element 48 is, as shown in Figure 8, biased

to hold the buffer element 40"at a position by which, in use, it will contact the pendulum 14 during a part of each swing.

The infra-red detection unit 16"monitors the movement of the arm element 48. The infra-red emitter 18"and detector 20"are directly opposed, as shown by way of example in Figures 9 and 11, so that, when the buffer element 40"is not in contact with the pendulum 14, the arm element 48 interrupts the infra-red beam emitted by the emitter 18".

The solenoid coil (not shown in Figures 8 to 11) is, similarly to the first embodiment, in a de-energised or substantially de-energised state when the clock needs no correction.

As the pendulum 14 swings and contacts the buffer element 40", the arm element 48 is, as shown in Figure 10, angularly displaced about the pivot point P which causes the arm element 48 to be moved from the infra-red beam.

The housing 12"is positioned so that the arm element 48 is only moved from the infra-red beam through a small sector of the arc of the swing of the pendulum 14.

Similarly to the second embodiment, the sector typically equates to a range of 5 millimetres (mm) to 25 mm of swing and is the end portion of the arc nearest to the housing 12".

Over a period of time, the movement of the arm element 48 from the infra-red beam enables the beat rate of the pendulum 14 to be electronically determined by the detection circuit 28 of the control unit 26 and output as the signal PB to the comparing circuit 30.

If it is determined that the clock is running slowly, the comparing circuit 30 outputs an appropriate signal to the energisation circuit 32 whereby the solenoid coil is energised. This has the effect of resisting movement of the armature 38", and consequently also the arm element 48, and thereby truncating the arc of the pendulum 14 as described above.

It should be noted that, by virtue of the device 10, the clock may tend to speed up. This may need to be taken into account during the calculation for the amount by which the clock should be slowed.

Furthermore, since some energy will inevitably be dissipated during contact between the pendulum 14 and the buffer element 40,40', 40", additional mass may be required on the going train of the clock.

Frictional losses, which will transform into losses in pendulum energy, should be minimised where at all possible, and thus the angle of incidence between the buffer element 40,40', 40"and the pendulum 14 is critical.

Although described with relation to all kinds of pendulum clock, the device 10 is particularly suitable for use with large pendulum clocks. A large pendulum clock is typically classed as being a pendulum clock having between 900 beats-per-hour and 7,200 beats-per-hour.

It is thus possible to provide an automatic regulation device which can be used on any pendulum clock. It is also possible to provide a method by which a pendulum clock can be automatically regulated.

The embodiments described above are given by way of example only and various modifications will be apparent to persons skilled in the art without departing from the scope of the invention as defined by the appended claims. For example, instead of the infra-red detection unit, the monitoring means may utilise any suitable means by which the beat rate of the pendulum can be determined, such as Hall-Effect proximity detection and/or a permanent magnet and sensing coil arrangement.

Claims

CLAIMS 1. A pendulum clock auto-regulation device for automatically regulating a pendulum clock of the kind as hereinbefore defined, the device comprising means for monitoring the beat rate of the pendulum, means for comparing the beat rate with an independent time base, and means for adjusting the beat rate based on the comparison.
2. A device as claimed in claim 1, wherein the adjusting means increases the beat rate of the pendulum.
3. A device as claimed in claim 1 or claim 2, wherein the adjusting means truncates the arc described by the pendulum.
4. A device as claimed in claim 3, wherein the adjusting means comprises a buffer element which can apply a retarding force and an accelerating force to the pendulum.
5. A device as claimed in claim 4, wherein the buffer element is selectively movable to engage the pendulum during its swing.
6. A device as claimed in claim 5, wherein the monitoring means is independent of the adjusting means.

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7. A device as claimed in claim 5 or claim 6, wherein the monitoring means directly monitors the movement of the pendulum.
8. A device as claimed in claim 4, wherein the buffer element engages the pendulum during a part of every swing.
9. A device as claimed in claim 8, wherein the monitoring means monitors the movement of the pendulum through the movement of the buffer element.
10. A device as claimed in any one of the preceding claims, wherein the monitoring means comprises an infra-red detection unit through which the beat rate of the pendulum is electronically determined.
11. A device as claimed in any one of the preceding claims, wherein the independent time base is a precision time base, such as a fixed crystal oscillator, the Rugby Time Signal service, a GPS satellite signal, and/or the mains electricity supply.
12. A device as claimed in any one of the preceding claims in combination with a pendulum clock of the kind as hereinbefore defined.
13. A method for automatically regulating a pendulum clock of the kind hereinbefore defined by using a pendulum clock auto-regulation device in accordance with any one of the preceding claims, the method comprising the steps of:

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a) suitably positioning the device adjacent to a pendulum of a pendulum clock, and b) setting the said clock to run slow.
14. A method as claimed in claim 13, wherein step (b) includes determining whether the said clock is an accurate timekeeper or an erratic timekeeper, and, if the clock is an erratic timekeeper, determining the maximum amount of gain over a given period and setting the clock to run slow by the maximum gain.
15. A method for automatically regulating a pendulum clock of the kind hereinbefore defined, the method comprising the steps of : a) setting the clock to run slow, b) comparing the beat rate of the pendulum with an independent time base, and c) truncating the arc described by the normal swing of the pendulum until the beat rate of the pendulum is synchronised or substantially synchronised with the independent time base.
16. A method as claimed in claim 15, wherein step (a) includes determining whether the said clock is an accurate timekeeper or an erratic timekeeper, and, if the

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clock is an erratic timekeeper, determining the maximum amount of gain over a given period and setting the clock to run slow by the maximum gain.
17. A pendulum clock auto-regulation device substantially as hereinbefore described with reference to the accompanying drawings.