GB2045994A - Monitoring Device - Google Patents

Abstract

Wear of a stylus of record playing equipment is monitored with a device having a sensor (5) which is actuated whenever the stylus is used. The sensor operates a counter, for example by controlling feed of time- based electrical pulses from a pulse generator (6) to the counter (9); and an indicator (10), such as an electrical digital display device, produces a monitorable indication of the count obtained, for example as a numerical display of hours of playing time. <IMAGE>

Description

SPECIFICATION Monitoring Device This invention relates to a monitoring device for monitoring wear of a stylus of record playing equipment.

Styli as used in record playing equipment are subject to wear and are required to be changed after a certain period of use if record damage is to be avoided. Such period is usually assessed in terms of playing hours or numbers of records played and it is incumbent on the user to monitor such a factor in order to be able to change the stylus at the appropriate time. Inevitably, however, the problem arises that it is difficult for the user to effect such monitoring in a reliable but convenient manner.

An object of the present invention is to overcome or at least appreciably reduce this problem.

According to the invention therefore there is provided a monitoring device, for monitoring wear of a stylus of record playing equipment, comprising a sensor adapted to be actuated in correspondence with use of the stylus, a counter connected to the sensor and adapted to be operated on actuation of the sensor thereby to produce a count representative of the extent of said use of the stylus, and an indicator connected to the counter and adapted to produce an indication representative of a count produced by the counter.

With this arrangement it will be appreciated that the user of the record playing equipment can be provided with an indication of the extent of use of the stylus whereby such user can monitor the wear of the stylus in a simple and convenient yet reliable manner.

With regard to the sensor this may take any suitable form and may be associated with the stylus, such as to respond to use thereof, in any suitable manner. For example, the sensor may be adapted to be actuated in correspondence with movement of a part of the record playing equipment, such as the tone-arm thereof, which part moves when the stylus is used. Thus, said sensor may comprise a lever or pressure-sensitive body or pad or other device which is arranged to be actuated in correspondence with application of a force thereto by said part in one position of movement thereof.In particular, said sensor may be arranged to be actuated by movement thereof from a first position to a second position, and a spring may be provided for urging said sensor to the said second position thereof, said sensor being arranged to be held in the said first position thereof by application of said force thereto. In one embodiment, the sensor comprises a projecting arm positioned so that the tone-arm of the equipment rests against same when in the out-ofuse rest position thereof and moves out of contact with the sensor when the tone-arm lifts and pivots into the record playing position thereof.

Alternatively, however, the sensor may be arranged to be actuated by a moving part of the equipment other than the tone-arm, such as the turntable or an internal link or drive connection which transmits motion to, or moves in correspondence with, the tone-arm or turntable.

Preferably, the sensor is arranged to produce an electrical output on actuation thereof, such output arising from the making or breaking of electrical contacts, or the variation of an electrical parameter such as resistance or capacitance or the like.

The sensor may be adapted to be actuated without dependence on the application of a force thereto, and in this case the sensor may comprise a capacitive or conductive or inductive or magnetic or other proximity detector which responds to the presence of a moving part of the equipment (or of an element such as a magnet or conductive element mounted on said moving part) in the immediate vicinity of or in contact with the sensor, or to movement of such part (or element) closely past the device. It is also possible to utilise a sensor having a radiation generating source and a radiation receiving element, the transmission of radiation (e.g. light or infra-red) between such source and element being effected or interrupted or modified (thereby for example to modify the electrical output or property of the element) in dependence on the position of a moving part of the equipment.Further, the sensor may comprise an electrical pick-up element or circuit which is applied in close proximity to or is connected to electrical circuitry of the record playing equipment so as to respond to the production of audio signals within the equipment or to the flow of electric power used to operate devices which effect or control movement of parts of the equipment.

The counter may also take any suitable form and then may be of a wholly mechanical nature or may be electromechanical or electronic. Preferably, however, an electronic counter is used and this may be connected to a pulse generator or the like so that a time-based count is produced; although alternatively or additionally a count based on the number of incidences of actuation of the sensor means may be produced. In order to ensure that the counter can produce a count which is of a cumalative nature, the counter may be arranged to be continuously powered and/or non-erasable memory devices may be utilised (i.e. devices which retain stored information even when disconnected from a power source).

Extremely low power consumption circuitry which can be powered continuously for a very long period of time by a small battery may be preferred.

The said indicator may be of any suitable kind and may be arranged to give an indication which is updated to enable the extent of use of the stylus to be periodically monitored or, alternatively so as to give an indication only when a predetermined extent of use is attained.

Preferably the indicator comprises a visual display device which may be an electronic digital display of an LED or LCD kind. Such display may be continously visible or may be visible only on an intermittent basis or when a switch is operated.

Where continuous display is required a device of the LCD kind may be preferred.

The counter and the visual display device may be arranged to give a count (in terms of hours and/or numbers of records or otherwise) which is initially set to zero for a new stylus and which provides a visual reminder that the stylus should be changed when the displayed count reaches a predetermined value corresponding to the maximum recommended period (or number of occasions) of use of the particular stylus.

Alternatively the counter and display device may be initially set to the predetermined maximum count and the arrangement may be such that the count reduces to zero.

A warning device may be incorporated which gives visual and/or audible warning when the count reaches the level at which replacement of the stylus is recommended.

Appropriate controls may be provided to enable the counter and indicator to be reset when a new stylus is fitted and, if desired, to enable the warning device (where this is provided) to be set for the different kinds of styli which may be used.

The monitoring device of the invention may be incorporated as original equipment within record playing equipment or may be provided as a separate device for use in conjunction with existing equipment. In the latter case, the device will most preferably be in the form of a selfcontained unit provided with an appropriate mounting device and incorporating its own power source.

The invention will now be described further by way of example only and with reference to the accompanying drawing in which:~ Fig. 1 is a diagrammatic perspective view showing one form of monitoring device according to the invention applied to the arm of record playing equipment; and Fig. 2 is a block circuit diagram of the monitoring device.

The monitoring device has a housing 1 which is of small dimensions suited to the positioning of same adjacent the arm 2 of conventional record playing equipment. The housing 1 is provided with fixing means comprising for example fixing screws, adhesive pads or the like for holding the housing securely in position on the deck of said equipment. In the drawing an adhesive pad 3 is shown beneath the housing.

The housing 1 contains a microswitch 4 which comprises contacts which are opened and closed by rotation of a cam member (not shown) about a horizontal axis. The cam member is connected to a spring-loaded lever 5 which projects upwardly from the back of the housing 1 and is engaged by the arm 2, when such arm is in the out-of-use rest position thereof, so as to be held against the spring loading thereof in a substantially vertical disposition in which the switch contacts are open.

When the arm 2 moves into the operational position thereof, the lever 5 pivots slightly to one side under the action of the spring loading thereof and the cam member is rotated to a position at which it closes the switch contacts.

Within the housing 1 , the switch 4 is connected to electronic circuitry (preferably including the low power consumption integrated circuit components and possibly micropressor elements), such circuitry including a pulse generator 6 (a crystal oscillator operating at 215Hz), a divider chain 7 which divides the output of the pulse generator 6 by 2'5Hz to give one pulse per second, a further divider 8 which divides the output of the divider 7 by 3600 to give one pulse per hour and a counter arrangement 9 comprising three successive dividers each of which divides by 10 whereby the output of the divider 8 is converted to a count up to 1000 hours. Outputs from the counter arrangement 9 are connected to a liquid crystal display unit 10 via a decoder 1 such unit 10 being visible at a front side of the housing 1.The counter arrangement 9 is also connected to an alarm circuit 12 via a logic circuit 13. The logic circuit 13 is connected to a pre-set alarm level reference device 14 and the alarm circuit 12 has an output connected to the display unit 10. The divider 7 is connected via a driver device 1 5 to the decoder 1 1. A reset button 1 6 accessible on top of the housing 1 is connected to reset inputs of. the dividers 7 to 9. The circuitry is powered from a long life battery which is mounted within the housing and which is accessible on removal of a cover 17 at the side of the housing 1.

The dividers 7 to 9 are all set to zero with the reset switch 16 when a new stylus is fitted in the usual head on the arm 2. The counter arrangement 9 and hence the display on the unit 10 remains at zero until pulses are fed to the divider 7 from the pulse generator 6. When the arm 2 is in the out-of-use position (as shown in Fig. 1), the switch 4 is open and the pulse generator 6 is not operational. Whenever the arm 2 is moved to its operational position, as in the case where a record is played, the lever 5 pivots (due to the spring loading of same) and the switch 4 is closed to effect operation of the pulse generator 6.

The counter arrangement 9 counts the divided output of the pulse generator 6 and the display on the unit 10 changes from zero to give an increasing numerical (three digit) display indicative of the time in hours (from 1 to 999), during which the stylus has been used. At the end of a period of use, operation of the pulse generator 6 is arrested when the arm 2 returns to its rest position, and the count (and the display on the unit 10) are held at the value reached. During subsequent periods of use, the count (and the displayed value) increase on a cumulative basis.

The count may be displayed permanently or if desired only when the arm 2 is in its operational position. During counting, the display on the unit 10 may change periodically more frequently than the change in the hour digit to give a readily noticeable indication of the operation of the system. This may be achieved by causing a decimal point or other indicator on the display to flash every second. Alternatively provision may be made for a fourth digit which displays minutes and which changes say every six minutes.

When a predetermined maximum count is reached corresponding to the maximum recommended playing time with the particular stylus (and for which the counter is permanently set or alternatively is pre-adjusted with the device 14), the alarm circuit 12 is triggered and an indication is given to the user to the effect that the stylus should be changed (or that the time for replacement is imminent). The alarm indication may involve actuation of the display unit 10 so as to display a word such as "End" or "Stop" which can be displayed using a three or four digit 7segment display unit. Such word could flash (say every second) alternately with the numerical display.

Alternatively or additionally any other suitable visualEand/or audible alarm indication can be used.

With this arrangement, the user can reliably, yet simply and conveniently, monitor wear of the stylus.

It is of course to be understood that the invention is not intended to be restriced to the details of the above embodiment which are described by way of example only. Thus, for example, if desired, the generator 6 may operate continuously and the switch 4 may be arranged to interrupt connection thereof to the divider 7. In this case it is possible to use the pulse generator 6 also to operate a time display.

Claims (19)

Claims

1. A monitoring device for monitoring wear of a stylus of record playing equipment, comprising a sensor adapted to be actuated in correspondence with use of the stylus, a counter connected to the sensor and adapted to be operated on actuation of the sensor thereby to produce a count representative of the extent of said use of the stylus, and an indicator connected to the counter and adapted to produce an indication representative of a count produced by the counter.

2. A monitoring device according to claim 1, wherein the sensor is adapted to be actuated in correspondence with movement of a part of the record playing equipment which part moves when the stylus is used.

3. A monitoring device according to claim 2, wherein the said part is the tone-arm of the equipment.

4. A monitoring device according to claim 2 or 3, wherein said sensor is arranged to be actuated in correspondence with application of a force thereto by said part in one position of movement thereof.

5. A monitoring device according to claim 4, wherein said sensor is arranged to be actuated by movement thereof from a first position to a second position.

6. A monitoring device according to claim 5, wherein a spring is provided for urging said sensor to the said second position thereof, and said sensor is arranged to be held in the said first position thereof by application of said force thereto.

7. A monitoring device according to claim 5 or 6, wherein said sensor comprises a projecting arm arranged to be engaged by said movable part.

8. A monitoring device according to claim 2 or 3, wherein said sensor comprises a proximity device adapted to be actuated in dependence on the proximity of the said part thereto.

9. A monitoring device according to any one of claims 1 to 8, wherein said sensor is arranged to produce an electrical output dependent on actuation thereof.

10. A monitoring device according to claim 7, wherein said sensor incorporates an electrical switch which is arranged to be operated on actuation of the sensor.

11. A monitoring device according to any one of claims 1 to 10, wherein the counter is an electronic counter.

12. A monitoring device according to claim 1 1, wherein the counter is arranged to be connected to a pulse generator so as to produce a timebased count.

13. A monitoring device according to any one of claims 1 to 12, wherein the said indicator is a visual display device.

14. A monitoring device according to claim 13, wherein the said visual display device is adapted to produce an updated indication to enable the extent of use of the stylus to be periodically monitored.

15. A monitoring device according to claim 13 or 14, wherein the visual display device comprises an electronic digital display device.

16. A monitoring device according to any one of claims 1 to 1 5, further including a warning device which operates to give a visual and/or audible warning when a predetermined count is reached.

17. A monitoring device according to any one of claims 1 to 16, which is a self-contained unit having a housing adapted to be mounted on the said equipment.

18. A monitoring device substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

19. Record playing equipment incorporating a monitoring device according to any one of claims 1 to 18.