GB1596630A - Control devices - Google Patents

Description

(54) CONTROL DEVICES (71) We, SMITHS INDUSTRIES LI MITED, a British Company of Cricklewood, London NW2 6JN, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to control devices, and, more particularly, though not exclusively, to control devices for controlling central heating systems.

Heretofor control devices for central heating systems have comprised electromechanical devices and included an a.c.

synchronous motor of the oscillation-start type and a gear train having an output shaft that is rotated through one complete revolution every twenty-four hours. The spindle carries a dial having a twenty-four hour scale graduated in quarter-hour sections, and four tappets which are adjustable around the dial to select two periods during which the system is to be operated, one pair of alternative tappets defining the commencement of the periods while the other tappets define the ends of their respective periods.

Although such control devices function satisfactorily, they tend to be rather noisy, mainly because of the knocking of the gear teeth. Also, the control devices have a relatively large number of moving parts and the resultant wear of these parts tends to reduce 4he life of the control devices.

It is an object of the present invention to provide a control device which overcomes the aforementioned disadvantages.

According to the present invention there is provided a control device comprising a time scale, visual display means having a plurality of electrically-energisable display regions disposed adjacent to the time scale which correspond to the respective and individual portions of the time period represented by the time scale and which are arranged to be energised for the duration of their respective said portions of the time period to provide with the time scale a visual indication of time, and means for sensing energisation of the visual display means, the said sensing means being movable relative to the visual display means to select the display regions which are to be sensed thereby and being arranged to supply an electrical control signal whenever a selected display region is electrically energised.

Each display region may be arranged, when energised, to be maintained energised during the remainder of the said time period.

The sensing means may be optical sensing means. In such a case, the optical sensing means may comprise a light guide, one end of which is to overlie the respective selected display region, to transmit light received from that display region, and a transducer which is disposed at the other end of the light guide and to generate an electric signal in response to any light transmitted along the light guide.

The optical sensing means may be arranged partially to overlie the selected display regions.

The display regions may be arranged in sequence in the order in which the regions are to be energised, and, in these circumstances, the display regions may be spaced apart along a path.

The control device may include means for generating electrial signals to energise the display regions.

The control device may include at least one pair of said sensing means, the sensing means being movable relative to one another.

Various forms of control devices in accordance with the present invention for controlling a central heating system will now be described, by way of example, with reference to the accompanying drawings in which: Figure 1 is a plan view of one form of the control device having a circular display panel; Figure 2 is a diagrammatic side view of the control device of Figure 1 partly in section; Figure 3 is a diagram showing an alternative form of display panel; Figure 4 is a diagram showing the display panel of Figure 3 with an alternative form of display; Figure 5 is a sectional side view of an electroluminescent display panel for the control devices; and Figures 6 and 7 are diagrams showing still further forms of the display.

The control devices all include a display panel having a plurality of electricallyenergisable visual display regions which correspond to respective and individual time periods and which are to be energised once during each twenty-four hours. The display regions are spaced apart along a path of either curved or straight form and a time scale is disposed adjacent the display regions to indicate to the user of the control devices the individual time periods during the twenty-four hours allocated to each of the display regions.

The control devices are for operating a central heating system twice during each twenty-four hours and include two pairs of optically-sensitive tappets for selecting these time periods. One tappet of each pair defines the commencement of the respective time period while the other tappets define the ends of respective ones of these periods.

The tappets are mounted for movement along the path defined by the display regions which are to be sensed by the tappets, and the tappets are each arranged to supply an electrical signal whenever the respective selected display regions are electrially energised. The tappets overlie the selected display regions, it being arranged that the tappets only partially overlie these display regions so that the users of the control devices may readily view the display regions and determine the time periods during which the control device has been selected to operate the control system and the state of the control device and the controlled system.

One form of such a control device is shown in Figures 1 and 2. Referring to Figures 1 and 2, twenty-four of the said display regions are provided, one for each hour of the twenty-four hour period, the display regions being constituted by lamps 10, such as for example, light-emitting diodes or gas-discharge tubes. The lamps 10 are mounted on a disc 11 of insulating material with the lamps being disposed adjacent the outer peripheral edge of the disc and spaced apart around the disc to define a circular path of the said display regions. A circular time scale 12 is provided on the disc 11 adjacent to and concentric with the path of the display regions. The disc 11 is disposed in a circular aperture 13 in an upper wall 14 of a rectangular metal housing 15 and carried by a tubular metal support 16 mounted on a base wall 17 of the housing.

The lamps 10 are sequentially energised by a voltage provided by a supply voltage and timer circuit 18 connected to mains supply, the timer being arranged at the end of each hour to transfer the supply voltage to the next lamp in the sequence and de-energise the preceding lamp 10. This voltage is delivered to the lamps via electric cables 19 which extend through the tubular support 16, and a printed circuit formed on the lower surface (Figure 2) of the disc 11.

The control device includes four opticallysensitive tappets 20 to 23 pivotally mounted on the tubular support 16 and which extend through an annular space between the disc 11 and the housing 15 and partially overlie at their free ends the path of the display regions. In use, the tappets 20 to 23 are positioned along the path of the display regions to select which of the lamps 10 are sensed by the tappets and thus the two periods during which the control system is to be operated. The tappets 20 to 23 are shown adjusted to sense energisation of the lamps 10 representative of, respectively, the sixth, ninth, seventeenth and twenty-second hours of the twenty-four hour period represented by the lamps. The tappets 20 to 23 each include an elongate body 24 of, for example, perspex or any other suitable transparent plastics material, one end of which overlies the respective. selected lamp 10. Each elongate body 24 is shaped to define a guideway to transmit light received from the selected lamp 10 to a photo-cell 25 disposed at the other end of the guideway. The photo-cell 25 supplies an electric signal along an electric cable 26 whenever it receives light transmitted along the guideway from the transmitted lamp 10. The cables 26 extend through the tubular support 16 and are connected to a semiconductor switching device 27 which responds to the signals from the photo-cells 25 and supplies appropriate control signals to the central heating system.

The tappets 20 to 23 are arranged in pairs the switching device 27 being arranged to supply control signals to switch ON the central heating system whenever the lamps 10 adjacent the tappets 70 and 22 are energised, and to supply control signals to switch OFF the central heating system whenever the lamps 10 adjacent the tappets 21 and 23 are energised.

The lamps 10 may be arranged in a straight path rather than a circular or arcuate path. Such a arrangement is shown in Figure 3 where the lamps 10 are mounted on a strip 28 of insulating material. In this arrangement the tappets 20 to 23 are slidably mounted on an elongate metal support disposed beneath the strip 28 and extending parallel to that strip.

The display regions may be of other shapes than circular, for example, of rectangular or square shape. One such alternative arrangement is shown in Figure 4 where the display comprises rectangular regions 29. It is visualised that such a form of the display could readily be provided by an electroluminescent or liquid-crystal display.

A panel for providing such an electroluminescent display is shown in Figure 5, the panel including a rectangular substrate 30 of glass forming the face of the display panel on which is formed by a conventional photo-etching process a transparent, positive electrode 31. A layer 32 of phosphor material is sandwiched between the positive electrode 31 and a negative electrode 33 comprising a multiplicity of electrode sections shaped to define respective ones of the display regions. The exposed surfaces of the layer 32 and the electrode 33 are coated with a layer 34 of electrically insulating lacquer.

In order to provide a liquid crystal display rather than an electro-luminescent display, the electrodes 31 and 33 are formed on respective sheets on glass, the glass sheets being spaced apart from one another by 1 or 2 thousandths of an inch with the electrodes 31 and 33 facing one another and the space between these sheets being filled by a liquid crystal material.

The display may comprise individual display regions for each quarter of an hour of the twenty-four hour display period. Two such displays are shown in Figures 6 and 7 where the displays are provided by display regions 35 spaced apart from one another and arranged to provide, respectively, a straight display and a curved display. With these displays the display regions are arranged, when energised, to remain energised for the remainder of that twenty-four display period so that the displays provide a strip of energised display regions giving a visual indication of the elapsed portion of the twenty-four period. The display regions of the two displays are coupled to a solid state clock circuit which is arranged to generate a clock pulse to energise the next display region every fifteen minutes.

Various modifications may be made to the embodiments described without exceeding the scope of the invention. For example, the tappets 20 to 23 may comprise electrical sensors rather than optical sensors and be arranged to sense whether operating voltages are supplied to the respective display regions rather than sense whether the display regions are illuminated.

Furthermore, in the embodiment shown in Figures 1 and 2, the lamps 10 may be arranged so that when each lamp 10 is energised, the lamp is maintained energised for the remainder of the twenty-four hour period of the display rather than being de-energised when the next lamp is energised.

WHAT WE CLAIM IS: 1. A control device comprising a time scale, visual display means having a plurality of electrically-energisable display regions disposed adjacent to the time scale which correspond to respective and individual portions of the time period represented by the time scale and which are arranged to be energised for the duration of their respective said portions of the time period to provide with the time scale a visual indication of time, and means for sensing energisation of the visual display means, the said sensing means being movable relative to the visual display means to select the display regions which are to be sensed thereby and being arranged to supply an electrical control signal whenever a selected display region is electrically energised.

2. A control device according to Claim 1, wherein each display region is arranged, when energised, to be maintained energised during the remainder of the said time period.

3. A control device according to Claim 1 or Claim 2, wherein the said sensing means is an optical sensing means.

4. A control device according to Claim 3, wherein the optical sensing means comprises a light guide, one end of which is to overlie the respective selected display region, to transmit light received from that display region, and a transducer which is disposed at the other end of the light guide and to generate an electric signal in response to any light transmitted along the light guide.

5. A control device according to Claim 3 or Claim 4, wherein the optical sensing means is arranged partially to overlie the selected display region.

6. A control device according to any one of the preceding claims, wherein the display regions are arranged in sequence in the order in the regions which are to be energised.

7. A control device according to Claim 6, wherein the display regions are spaced apart along a path.

8. A control device according to any one of the preceding claims, including means for generating electric signals to energise the display regions.

9. A control device according to any one

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (10)

**WARNING** start of CLMS field may overlap end of DESC **. The lamps 10 may be arranged in a straight path rather than a circular or arcuate path. Such a arrangement is shown in Figure 3 where the lamps 10 are mounted on a strip 28 of insulating material. In this arrangement the tappets 20 to 23 are slidably mounted on an elongate metal support disposed beneath the strip 28 and extending parallel to that strip. The display regions may be of other shapes than circular, for example, of rectangular or square shape. One such alternative arrangement is shown in Figure 4 where the display comprises rectangular regions 29. It is visualised that such a form of the display could readily be provided by an electroluminescent or liquid-crystal display. A panel for providing such an electroluminescent display is shown in Figure 5, the panel including a rectangular substrate 30 of glass forming the face of the display panel on which is formed by a conventional photo-etching process a transparent, positive electrode 31. A layer 32 of phosphor material is sandwiched between the positive electrode 31 and a negative electrode 33 comprising a multiplicity of electrode sections shaped to define respective ones of the display regions. The exposed surfaces of the layer 32 and the electrode 33 are coated with a layer 34 of electrically insulating lacquer. In order to provide a liquid crystal display rather than an electro-luminescent display, the electrodes 31 and 33 are formed on respective sheets on glass, the glass sheets being spaced apart from one another by 1 or 2 thousandths of an inch with the electrodes 31 and 33 facing one another and the space between these sheets being filled by a liquid crystal material. The display may comprise individual display regions for each quarter of an hour of the twenty-four hour display period. Two such displays are shown in Figures 6 and 7 where the displays are provided by display regions 35 spaced apart from one another and arranged to provide, respectively, a straight display and a curved display. With these displays the display regions are arranged, when energised, to remain energised for the remainder of that twenty-four display period so that the displays provide a strip of energised display regions giving a visual indication of the elapsed portion of the twenty-four period. The display regions of the two displays are coupled to a solid state clock circuit which is arranged to generate a clock pulse to energise the next display region every fifteen minutes. Various modifications may be made to the embodiments described without exceeding the scope of the invention. For example, the tappets 20 to 23 may comprise electrical sensors rather than optical sensors and be arranged to sense whether operating voltages are supplied to the respective display regions rather than sense whether the display regions are illuminated. Furthermore, in the embodiment shown in Figures 1 and 2, the lamps 10 may be arranged so that when each lamp 10 is energised, the lamp is maintained energised for the remainder of the twenty-four hour period of the display rather than being de-energised when the next lamp is energised. WHAT WE CLAIM IS:

1. A control device comprising a time scale, visual display means having a plurality of electrically-energisable display regions disposed adjacent to the time scale which correspond to respective and individual portions of the time period represented by the time scale and which are arranged to be energised for the duration of their respective said portions of the time period to provide with the time scale a visual indication of time, and means for sensing energisation of the visual display means, the said sensing means being movable relative to the visual display means to select the display regions which are to be sensed thereby and being arranged to supply an electrical control signal whenever a selected display region is electrically energised.

2. A control device according to Claim 1, wherein each display region is arranged, when energised, to be maintained energised during the remainder of the said time period.

3. A control device according to Claim 1 or Claim 2, wherein the said sensing means is an optical sensing means.

4. A control device according to Claim 3, wherein the optical sensing means comprises a light guide, one end of which is to overlie the respective selected display region, to transmit light received from that display region, and a transducer which is disposed at the other end of the light guide and to generate an electric signal in response to any light transmitted along the light guide.

5. A control device according to Claim 3 or Claim 4, wherein the optical sensing means is arranged partially to overlie the selected display region.

6. A control device according to any one of the preceding claims, wherein the display regions are arranged in sequence in the order in the regions which are to be energised.

7. A control device according to Claim 6, wherein the display regions are spaced apart along a path.

8. A control device according to any one of the preceding claims, including means for generating electric signals to energise the display regions.

9. A control device according to any one

of the preceding claims, wherein the control device includes at least one pair of said sensing means, the sensing means being movable relative to one another.

10. A control device substantially as hereinbefore described with reference to the accompanying drawings.