GB2122400A - A safety warning system primarily for persons living alone - Google Patents

Abstract

A system to improve the safety of persons usually living alone, which does not involve any conscious act, such as pressing a switch, or using a telephone, on the part of the person concerned. The warning will operate automatically if, for example, the person fails to get up in the morning or go to bed in the evening. The circuitry includes a number of special features. Low voltages are involved for safety, and extremely small currents are used, in some cases for an infinitessimally short time, for economy. The system can be used for individual houses, or in conjunction with neighbours or a warden's post. Numerous methods of achieving the above objectives are given, including a specially adapted clock, a latching relay, thyristor circuits and an integrated circuit timer.

Description

SPECIFICATION A safety warning system primarily for persons living alone.

The system is illustrated diagrammatically in Fig. 1.

M is an off/on switch which does not stay permanently on and which operates without the person concerned having to perform a conscious act. An example of M is an electrical pressure pad placed under the carpet on a step of the stairs or in any other suitable position. More than one pad can be used.

Contact is made when the person steps upon the pad and is broken when the person steps off.

S is the switching arrangement which determines when and under what circumstances the warning, W will be actuated.

S is controlled by the action of closing M and not by the time M remains closed. The latter has no relevance in the operation.

A simple basic circuit is shown in Fig. 2.

S, and S2 are switches operated by some form of timing mechanism, for example, a normal 1 2-hour or 24-hour clock.

S, is closed by the timing mechanism but opens again before S2 is closed.

When S2 is closed it remains closed until opened by the action of a solenoid or some other electrical device, A, actuated by the closing of switch M.

If M is not operated, S2 will remain closed with the result that when S, is closed again by the timing mechanism the warning will operate.

Thus, for example, if, on a 1 2-hour clock, S, is set for one o'clock and S2 for two o'clock and the person fails to get up in the morning the warning will operate at 1.00 p.m. since S2 will have been closed at 2.00 a.m. and not re-opened. If, however, the person does get up M will operate A, and S2 will open thus disconnecting the warning. The sequence, thus determined, will apply also at bed time. A special feature of the circuitry is that the operation of A breaks the circuit so that the drain on the electrical supply is extremely small.

Fig. 3 shows the circuitry when A (Fig. 2) is replaced by a specially adapted latching solenoid or relay. S2 is now a normal off/on switch which does not stay in the "on" position.

When current is passed through that part of the solenoid between terminals 1 and 2, connection is broken between 4 and 5, and made across 5 and 6. Similarly when current is passed between 2 and 3 connection is broken between 5 and 6 and made between 4 and 5.

Before the changeover from one mode to the other can be completed however the current has to flow in the solenoid for a finite time, usually of the order of milliseconds.

When M is closed there is an instantaneous circuit break between 4 and 5 which affects the solenoid and changeover will not take place.

A similar situation arises between 5 and 6 when S2 is closed. This difficulty is overcome by placing a capacitor, C, across 1 and 2, and across 2 and 3. These capacitors retain their charge long enough for the changeover to be completed. This arrangement ensures that no matter how long M or S2 is closed, the electrical supply is disconnected after an infinitesimally short time, producing maximum economy.

When S2 is closed, contact moves from 5,6 to 4,5. If M is not closed before S, is switched on the warning will operate. However, if M is closed, contact moves back from 4,5 to 5,6 and the warning will not operate.

Fig. 4 shows the circuitry when S, and S2 are connected to a Thyristor circuit.

When S2 is closed, current will flow through the thyristor T. This will continue even when S2 opens again. (S2 is a normal off/on switch which does not stay in the "on" position).

When S, is closed the thyristor current will by-pass the resitance R and actuate the warning W.

If, however, in the meantime, M is closed, the thyristor current will be quenched and the warning will not operate, and so on.

An example involving a semi-conductor clock module D, is shown in the block diagram, Fig. 5.

The module triggers an external circuit through sensitive relays E.

S, after assuming the "on" position will return to the "off" position after a pre-determined time and before S2 assumes the "on" position. S2 will remain in the "on" position until returned to the off position by the action of switch M. If S2 is not so returned before S, again assumes the "on" position, the warning will operate.

Fig. 6 shows the circuitry using an integrated circuit timer, P, and a thyristor, T.

The time interval is controlled by the value of the resistance R, and the capacitor C1, and can be 24 hours, for example.

E is a relay which in its normal mode is closed. When M is closed E is opened thus cutting off the power to the timer which is thus re-set to start its cycle over again.

If M is not closed the warning, W, will operate. Thus the warning will operate 24 hours, or any other interval decided upon, after the last time M was closed. This establishes the cycle.

In all the above examples the warning which might normally be placed outside the house could be placed in a neighbour's house or in a warden's office.

If a neighbour or a warden is involved, the arrangement shown in Figs. 7 and 8 can apply.

M is a pressure mat or some other auto-matic switch. T is a thyristor. L is a light emitting diode. R1, R2 and R3 are resistances of appropriate value and N is an onZoff press switch which is used to extinguish the thyristor current. The whole circuit except for M is placed in the neighbour's house.

In operation, the neighbour presses N, thus quenching the thyristor current. When the person living alone actuates the automatic switch M, current will flow in the thyristor circuit and L will emit light. This will continue even when M returns to the open position.

The neighbour will therefore be able to check at a glance whether the person living alone has got up or gone to bed or is even moving about the house, without having to interfere with the privacy of the person.

The arrangement can be extended to a number of houses (three are shown) connected, say, to a warden's post as in Fig. 8.

All the thyristor circuits are placed on a single board. The cycle begins with the warden opening N thus extenguishing all the light emitting diodes. Whenever M is closed in any house the corresponding light will come on.

Thus a light that is on will indicate that the person has, for example, got up. A glance at the board at say 1 2 noon will give an accurate picture of the situation in the houses, and any necessary action can be taken.

Claims (8)

CLAIMS 1. A system to improve the safety of persons, usually living alone, who may, through illness or injury or in some other way, be unable to assist themselves or even call for assistance. Inherent in, and central to, the system is the feature that no conscious act such as pressing an emergency button or using a telephone is required. The warning operates automatically if, for example, the person fails to get up in the morning or go to bed in the evening, or is rendered immobile due to an accident in the home, or to a sudden health disability. A special feature of the circuitry is the fact that only low voltages are required thus ensuring complete safety from electric shock, and that only extremely small currents are used, in some cases for only an infinitesimally short time, unless, of course, the warning is in operation. Only small transistor set batteries are therefore required. To increase the confidence of the person living alone, an emergency switch can be included, if this is considered necessary. CLAIMS (19 Sep 1983)

1. An alarm system, for use usually by persons living alone, in which two switches actuated by some form of timing mechanism such as a clock, are included in a special circuit in such a way as to cause the actual warning itself to operate if there is a period of inactivity on the part of the person concerned.

Activity such as stepping on an electrical pressure mat will prevent the warning from coming into operation.

The first switch is connected in series with the actual warning. The other switch is subject to a "latching" arrangement which will remain in the "on" state until the "latch" is released by the action of stepping on the mat.

The switches will not overlap except when the "latching" is in operation.

The clock will start the cycle over again at the set times for the switches. When it does come into operation the warning will do so at a pre-arranged fixed time each day or night.

This does not depend upon the last time the "latching" was released.

2. An alarm system as claimed in claim 1 with an electro-mechanical "latching" system.

3. An alarm system as claimed in claim 1 with an electrical "latching" system, for example, a double coil latching relay.

4. An alarm system as claimed in claim 3 with a condenser in parallel with each coil to enable the switchover to take place even though the supply voltage to the coils is cut off almost instantaneously during the operation of "latching" or "de-latching".

5. An alarm system as claimed in claim 1 with a thyristor "latching" system.

6. An alarm system as claimed in claim 1 using a semi-conductor module such as a digital clock module.

7. As claimed in the previous claims when used as a switching arrangement to switch on any independent separate alarm system, for example, an existing alarm system operated by pull switches. The present invention would be added to the pull switches or replace one of them.

8. As claimed in claim 7 to trigger off a warning for each individual house in a group arrangement of houses connected to a central point such as a warden's post.