GB2178173A

GB2178173A - Wind speed alarm

Info

Publication number: GB2178173A
Application number: GB08518467A
Authority: GB
Inventors: Anthony Williams
Original assignee: ZIG ZAG SCAFFOLDS Ltd
Current assignee: ZIG ZAG SCAFFOLDS Ltd
Priority date: 1985-07-22
Filing date: 1985-07-22
Publication date: 1987-02-04
Also published as: GB2178173B

Abstract

A wind speed alarm comprises a support member 2 mounting a displaceable element 5 which is arranged for pivotal movement under the force of the wind. The pivotal element 5 is adapted to contact conductive flange 11 to make an electric circuit and actuate a warning signal when the wind speed is such that the pivotal displacement of the element reaches a predetermined value. The flange 11 may be moved to vary the value at which the signal is actuated. A time delay may be incorporated to prevent operation by short gusts of wind. The apparatus is mounted on scaffolding or cranes. <IMAGE>

Description

SPECIFICATION Wind speed alarm This specification relates to a wind speed alarm.

Various devices are known for providing an audible and/or visible warning signal when wind speed exceeds a predetermined value.

Typically such devices involve an anemometer the rotating vanes of which are coupled to means arranged to produce an electrical signal indicative of wind speed, control circuitry being provided to produce a warning signal when the wind speed reaches a certain level.

However, such devices are principally precision devices adapted to produce accurate measurements and accordingly are relatively costly. Moreover, a device involving an anemometer is inconvenient in certain instances having regard to general lack of robustness and having regard to the need for the anemometer to be positioned quite carefully in relation to wind direction to achieve reliable results.

For example, in the building and construction industry there is a need for a wind speed alarm capable of providing a warning when the wind speed exceeds a certain level beyond which it is unsafe for personnel to mount scaffolding, operate cranes or perform other tasks where excess wind speed represents a safety hazard. Known devices of the type discussed above do not provide relatively inexpensive means suitable for mounting e.g.

to scaffolding for use as a wind speed alarm in this field.

Accordingly we now disclose a wind speed alarm comprising a support member mounting a displaceable element arranged for pivotal movement under the force of the wind, there being means associated with such element adapted to make an electrical circuit and actuate an associated means for providing a warning signal when the wind speed is such that pivotal displacement of the element reaches a predetermined value.

Such an apparatus may provide a robust and reliable wind speed alarm at relatively low cost suitable for use in, for example, the building and construction industry and in any other applications where excessive wind represents a hazard. The use of a pivotal element arranged to be displaced under the force of the wind coupled to means arranged to provide an alarm when displacement of the element reaches a predetermined value represents a considerable simplification in practical terms as compared with known devices involving traditional anemometers.

The means associated with the pivotal element adapted to make an electrical circuit upon predetermined displacement of the element may take any convenient form, and it is envisaged that the element could for example be coupled mechanically to a suitable switch means in the region of its pivotal mounting. In a particularly preferred embodiment, however, the pivotal element itself is electrically conductive and forms part of the alarm circuit. Thus, in such an arrangement the pivotal element is arranged to engage and thus make electrical contact with a fixed element appropriately spaced therefrom at said predetermined pivotal displacement of the element.Such an arrangement is advantageous having regard to practical simplicity and, moreover, with such a device the pivotal member may readily be mounted so as to be pivotal in any direction without the need for a complex multi-directional switch means to be associated therewith. Clearly, in most instances it is desirable for a wind speed alarm to be responsive to wind approaching from any direction and to variable gusts from a range of directions.

The pivotal element and support member therefor may take any convenient form. It is envisaged that the element may generally be in the form of a pendulum or other downwardly suspended electrically conducting element arranged within a fixed, tubular contact so that when the wind speed exceeds a certain value the element engages such contact and makes an electrical circuit to trigger the warning means.

However in a preferred embodiment the pivotal element comprises a generally tubular member which surrounds the fixed support member, which in this embodiment also forms part of the alarm circuit. Thus, the tubular member is pivotally mounted at its upper end to the support member via an electrically insulating coupling, and when the wind speed exceeds a certain level the lower part of the tubular member is pivotally moved into engagement with the support member so as to make electrical contact therewith. In a preferred such embodiment the tubular member is generally in the form of an inverted cup-like member and is supported by a simple pivotal bearing of insulating material provided at the upper end of the support member.

In a preferred embodiment means are provided whereby the sensitivity of the alarm may be varied. In the arrangement discussed above wherein the pivotal element comprises a tubular member, such means may conveniently be in the form of a sleeve axially movable along the support member and mounting an annular flange arranged for engagement with the inner surface of the tubular member.

With such an arrangement, it will be appreciated that the extent to which the tubular member must be pivoted to make contact with the flange, and thus the wind speed required to trigger the warning means, may be varied by altering the height of the flange on the support member.

In a preferred embodiment the alarm circuit includes means adapted to install a time delay between the making of the circuit by the pivotal element and the triggering of the warning means. Such a time delay of for example several seconds advantageously renders the alarm insensitive to short gusts of wind which may not represent a serious hazard.

The means for providing a warning signal may take any convenient form, and in a preferred embodiment an audible and visible warning is provided. The alarm as a whole is preferably combined into a self-contained robust unit adapted for example to be clamped to the hand rail of a scaffold tower. The unit is preferably a transportable battery powered unit An embodiment of wind speed alarm will now be described, by way of example only, with reference to the accompanying drawings, wherein: Figure 1 is a partly schematic side elevation of a wind alarm; Figure 2 illustrates the alarm circuit; and Figure 3 illustrates in more detail the pivotal element on an enlarged scale.

Referring to the drawings, a wind alarm 1 comprises a tubular support member 2 adapted to be vertically secured by means of a clamp 3 to for example, a hand rail of a scaffold tower. At the upper end of the support member 2 an insulating bearing 4 pivotally supports an inverted cup-like tubular member 5.

The alarm further comprises a housing 6 enclosing means for activating a warning signal in the form of a bleeper 7 and a bulb 8. As shown in Fig. 2, the tubular member 5 and support member 2 form part of the actuating circuit of the alarm. Thus, the tubular member 5 is electrically connected in the circuit by means of a wire 9 extending through the sup port member 2, the tubular member normally being electrically insulated from the support member by means of the bearing 4. Thus, in the normal condition of the alarm, when an on/off switch 10 of the device is closed, the alarm is not actuated since the circuit between the support member 2 and tubular member 5 is broken.

However, the tubular member 5 is freely pivotal in any direction, and accordingly as shown in Fig. 3 is displaceable under the force of the wind so that when the wind speed reaches a certain value the inner surface of the tubular member 5 engages a con ducting annular flange 11 carried by a sleeve 12 secured to the central support member 2.

Upon such engagement, the alarm circuit is made between the support member and tubu lar member, whereupon a time delay means 13 (Fig. 2) is energised. After a predetermined period of time of for example two seconds the means 13 closes a switch 14 which in turn triggers the warning means 7,8 of the device.

As also shown in Fig. 3, the sensitivity of the alarm may be varied by altering the height of the sleeve 12 and flange 11 on the support member 2. Thus, by raising the flange 11 a greater pivotal displacement of the member 5 is required to trigger the alarm, and consequently the alarm is actuated in response to higher wind speeds. The sensitivity range of the device may also be selected by providing a flange 15 or other suitable weighting means at the lower end of the member 5. Typically in the case of scaffold towers, the alarm may be adapted to provide a warning signal when the wind speed exceeds Force 4 on the Beaufort scale, although for other applications the alarm could be adapted to be triggered at higher or lower wind speeds.

Whilst certain broad aspects and specific features of a wind speed alarm have been described herein modifications may be apparent to those skilled in this art; the disclosure hereof is intended to encompass any such modifications.

Claims

1. A wind speed alarm comprising a support member mounting a displaceable element arranged for pivotal movement under the force of the wind, there being means associated with such element adapted to make an electrical circuit and actuate an associated means for providing a warning signal when the wind speed is such that pivotal displacement of the element reaches a predetermined value.

2. A wind speed alarm as claimed in claim 1 wherein the pivotal element forms part of the alarm circuit and is arranged to engage and make electrical contact with a fixed element appropriately spaced therefrom at said predetermined pivotal displacement of the pivotal element.

3. A wind speed alarm as claimed in claim 2 wherein the pivotal element comprises a generally tubular member which surrounds the fixed support member and which is pivotally moved into electrical contact therewith at said predetermined pivotal displacement.

4. A wind speed alarm as claimed in claim 3 wherein the tubular member is generally in the form of an inverted cup-like member and is supported by an insulating bearing at the upper end of the support member.

5. A wind speed alarm as claimed in any preceding claim further comprising means for varying the sensitivity of the alarm.

6. A wind speed alarm as claimed in claim 5 and in claim 3 or 4 wherein said means comprises a sleeve which is axially movable along the support member and which mounts a flange arranged for engagement with the in ner surface of the tubular member.

7. A wind speed alarm as claimed in any preceding claim wherein the alarm circuit in cludes means adapted to install a time delay between the making of the circuit by the pivo tal element and the actuation of the warning means.

8. A wind speed alarm as claimed in any preceding alarm in the form of a self-contained transportable unit adapted to be clamped on a handrail of a scaffold tower or the like.

9. A wind speed alarm substantially as herein described with reference to the accompanying drawings.