GB2255404A - Sensing apparatus - Google Patents

Abstract

Sensing apparatus includes a sensor positioned at or towards the free end of a stem 5 whose position and/or linear configuration can be varied thus enabling the sensor to be selectively located at one of a multiplicity of possible positions. The sensor may be infra-red, ultrasonic or optical. The stem may be filled with elastic foam to allow it to return to a set position if dislodged or it may be set in a position by filling it with a hardening resin. Applications include controlling taps on a wash basin, collision detection and security systems. <IMAGE>

Description

Improvements in and Relations to Sensina ApParatus This invention relates to non-contact sensing apparatus and more especially, but not exclusively, to such apparatus which comprises a sensor connected to transmit processed control signals to a switching device or display unit in response to detected variations in signals emitted and received by the sensor. The sensor may comprise a sensor sensitive to infra-red rays, the sensor including an emitter and receiver of such rays.

Alternatively, sensors sensitive to light, sound, RF waves, ultra-sonics and lasers may be employed.

Such non-contact sensing apparatus has been used previously in such applications as hands-free operated taps, hand driers and the like. These known devices may include a fixed body forming part of a tap assembly or a fixed plate positioned below a hand drier, the body or plate including a sensor connected to sense interferences in infra-red rays emitted by the sensor and to transmit signals to a solenoid or motor operable to turn a tap or drive a motor in response to such interferences being detected.

For tap and drier assemblies which have been designed specifically to include sensors, the sensors are generally positioned to provide clear access to the emitters and collectors of the sensors. In such cases, fixed conventional sensors can be employed. This is not always the case with existing assemblies to be converted to hands-free operation where the positioning of taps and other structures precludes the use of conventional infrared sensors.

There are, of course, many other applications where the presence of one or more infra-red detectors which operate in response to a break or interruption in infrared rays emitted from and received by a sensor of the detector can define a useful switch mechanism. Thus, such sensors can be usefully positioned to the rear of a vehicle to indicate closeness of a structure towards which the vehicle is reversing. Hitherto, the fixed nature of such sensors has seriously diminished the use to which they can be put. Additionally, infra-red detectors are used in security systems to detect the presence of intruders. Again, such detectors need to be located at positions which provide an uninterrupted field of vision.

In many locations, because of the fixed nature of the detectors such positions are few and far between.

The present invention sets out to provide sensing apparatus in which a sensor can be positioned selectively in a variety of fixed or movable positions to suit a particular assembly or user requirement.

According to the present invention in one aspect there is provided sensing apparatus including a sensor positioned at or towards the free end of a stem whose position and/or linear configuration can be varied thus enabling the sensor to be selectively located at one of a multiplicity of possible positions.

The sensor may be an infra-red sensor, an emitter and receiver of infra-red rays being positioned at or towards the free end of the flexible stem.

The stem is preferably flexible and may be produced from a plastics, rubber or metallic material which may be articulated in construction. Once sited, a hardenable resin or foam may be introduced into the stem to fix it in a required linear configuration. Alternatively, the stem may include an elastic filler to enable it to return to an original linear configuration should it be dislodged.

Signals from the sensor to a remote processor may, for example, be passed via electrical wires or optical fibres positioned within the interior of the stem.

In another aspect, the invention provides a noncontact switching device comprising a sensor including an emitter and collector of infra-red rays, a stem for fixing at one end to a structure and adapted to carry at or towards its free end the sensor, means for passing infrared rays to the emitter for transmission therefrom and means for passing collected infra-red rays from the collector to processing means forming part of the switching device, the processing means being adapted to pass processed control signals to provide switching signals for an assembly to be controlled.

The processor typically comprises a printed circuit board.

The invention will now be described by way of example only with reference to the accompanying diagrammatic drawings in which: Figure 1 is a perspective view of apparatus in accordance with the invention used to control the opening of taps of a conventional sink assembly; Figure 2 is a perspective view to an enlarged scale of sensing apparatus illustrated in Figure 1; Figure 3 is a plan view from above of a vehicle including alternative sensing apparatus in accordance with the invention; and Figure 4 shows to an enlarged scale the sensing apparatus illustrated in Figure 3.

Figure 1 illustrates a conventional sink assembly including a pair of taps 1 connected to discharge hot and cold water into a sink 2. Two wall mounted switching devices 3 and two surface mounted switching devices 4 are illustrated. In practice only one pair of such switching devices would be employed.

As will be seen more clearly from Figure 2, each switching device 3,4 essentially comprises an articulated plastics or metallic flexible stem 5 which carries at its free end a sensor 6 including an infra-red emitter 7 and collector 8. Alternatively, emitters and collectors suitable for emitting and receiving light, sound, RF waves, ultra-sonics or lasers may be employed. The flexible stem is secured at its other end to a mounting plate 9 attached to the respective wall or surface of the assembly. The linear configuration of the flexible stems and hence the positions of the sensors can be selected at will simply by bending the articulated stems. Two alternative configurations are shown in broken-line in Figure 2. Thus, structures which would otherwise have interrupted the fields of vision of the sensors can be avoided.Once in position, the linear configuration of the stems can be fixed by the introduction of hardenable resin or foam. Alternatively, an elastic filler may be employed to enable the stem to flex and then return to its original linear configuration if knocked or dislodged.

The sensors are connected to a processor 10 in the form of an electrical or electronic circuit board via electrical wiring 11 or optical fibres which pass along the length of the respective stems. If the beam of infrared rays emitted by one of the emitters 7 is broken by the presence of, for example, the hands of a user of the sink assembly, the resultant change in the signals transmitted from the respective collector 8 to the processor 10 is detected and an output signal transmitted to a signal receiver 12 in the form of a solenoid to open the respective tap or taps to allow hot and/or cold water to flow into the sink 2.

Operation of the taps would normally be time controlled in the sense that the solenoid 12 would operate to turn off the taps after a given period of time. Where a mixer tap is used, the degree of mixing of hot and cold water and consequently the temperature of the water entering the sink can be predetermined.

A further application of non-contact switching apparatus in accordance with the invention is illustrated in Figures 3 and 4 of the drawings. In this embodiment, a pair of infra-red sensors 14 are mounted one at each free end of a flexible stem 15 positioned at each corner of the rear of a vehicle 16. The stems may each carry an emitter and a collector. Alternatively, one stem may carry an emitter and the other a collector. The sensors are so positioned that the emitted beams of infra-red rays are broken as and when the rear of the vehicle approaches a fixed structure. Resultant electrical signals are employed, for example, to warn the driver of the closeness of a structure to which he is reversing. This is particularly useful when, for example, a heavy goods vehicle is reversing towards a structure such as a loading bay.The signals, which may be distance related, may be transmitted from the sensors to a visual display located in the driving cab of the vehicle to provide an analogue indication or digital reading of the distance between the rear of the vehicle and the structure towards which the vehicle is reversing.

Apparatus in accordance with the invention has many applications additional to those described above. Thus, flexible stem mounted infra-red emitters and collectors may be employed in security systems, the stems being suitably aligned to enable the sensors a wide field of vision without being obscured by, for example, curtains used to disguise the presence of the detection apparatus.

Also, flexible stem mounted infra-red sensors can usefully be employed in industrial locations to detect product stoppages; such sensors may, for example, be fixed to sides of conveyor belts to indentify hold-ups or plant failures. Flexible stem mounted sensors can also be used to probe deep into the workings of machinery to identify faults and possible break-downs.

It will be appreciated that the foregoing is merely exemplary of non-contact switching apparatus in accordance with the invention and that modifications can readily be made thereto without departing from the true scope of the invention. Thus, articulation of the stem may be achieved by means of a ball and socket joint positioned either at the stem's mounting point or at a position along the length of the stem. Also, fixed stems for the sensors may be employed, the shape and configuration of these stems being selected to provide ease of access to the sensors carried by the stems.

Claims (9)

CLAIMS:

1. Sensing apparatus including a sensor positioned at or towards the free end of a stem whose position and/or linear configuration can be varied thus enabling the sensor to be selectively located at one of a multiplicity of possible positions.

2. Apparatus as claimed in Claim 1 wherein the sensor is an infra-red sensor, an emitter and receiver of infra-red rays being positioned at or towards the free end of the flexible stem.

3. Apparatus as claimed in Claim 1 or Claim 2 wherein the stem is flexible.

4. Apparatus as claimed in Claim 3 wherein, once sited, a hardenable resin or foam is introduced into the stem to fix it in a required linear configuration.

5. Apparatus as claimed in Claim 3 wherein the stem includes an elastic filler to enable it to return to an original linear configuration should it be dislodged.

6. Apparatus as claimed in any one of Claims 1 to 5 wherein the sensor is operable to send signals to a remote processor via electrical wires or optical fibres positioned within the interior of the stem.

7. A non-contact switching device comprising a sensor including an emitter and collector of infra-red rays, a stem for fixing at one end to a structure and adapted to carry at or towards its free end the sensor, means for passing infra-red rays to the emitter for transmission therefrom and means for passing collected infra-red rays from the collector to processing means forming part of the switching device, the processing means being adapted to pass processed control signals to provide switching signals for an assembly to be controlled.

8. A device as claimed in Claim 7 wherein the processor comprises a printed circuit board.

9. Sensing apparatus substantially as herein described and as described with reference to Figures 1 and 2 or Figures 3 and 4 of the accompanying diagrammatic drawings.