AU702059B2

AU702059B2 - Enclosure for light sensor or emitter

Info

Publication number: AU702059B2
Application number: AU39125/95A
Authority: AU
Inventors: Peter Simon
Original assignee: HPM Industries Pty Ltd
Current assignee: HPM Industries Pty Ltd
Priority date: 1994-12-07
Filing date: 1995-11-28
Publication date: 1999-02-11
Anticipated expiration: 2015-11-28
Also published as: AU3912595A

Description

1- P/00/01 I Regulation 3.2

AUSTRALIA

Patents Act 1 990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Invention Title: ENCLOSURE FOR LIGHT SENSOR OR EMITTER 4 4 4. 9 4 *4 *44.4t 4 4W 94 4 9* *W 4 The following statement is a full description of this invention, including the best method of performing it known to us:- *4 4 4 9 4* 9* 4 *44**fd 4 4 (9 4 4 *4 4. C 4.

.4 GH&CO REF: P04210-TJ/RW:SD 2 This invention relates to an enclosure which is intended to accommodate a light sensor or emitter. The invention has been developed as a light sensor enclosure which provides for selective shading of a contained light sensor from an adjacent source of artificial light, and the invention is hereinafter described in this context.

However, it will be understood that the invention does have broader application, for example to an enclosure for a light emitter and one which provides for selective shading of a region into which energy is radiated by the emitter. It will also be understood that when reference is made herein to a light sensor or emitter, the term "light" should be construed as embracing all radiation falling within the optical region of the electromagnetic spectrum, including infra-red, visible and ultra-violet radiation.

Light sensors are employed in many situations, for example outside of domestic residences and in commercial areas, to detect for low levels of ambient light and to initiate energisation of artificial lighting when the ambient light level falls below a predetermined value.

Thus light sensors are normally placed in positions which are selected by electricians to facilitate electrical connection of the sensors to associated wirin and this 25 frequently results in the sensors being placed in proximity to artificial light sources. This practice frequently leads to unreliable operation of the sensors because any artificial light that impinges on a given sensor may be "seen" by the sensor as ambient lighting and, thus, cause an output to be produced that falsely :indicates a high level of ambient light.

When this occurs, the artificial light source will inappropriately be switched-off and, thereafter, the lighting system will cycle on-and-off until the ambient 35 light reaches a sufficiently high level to swamp the artificial light.

This problem may readily be avoided by careful placement of sensors, but the situation is not always b a *C a *a a a, 0 a a.a .a a a a.

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a a :1 re Ptd a 1 3 apparent to electricians who normally would be working in daylight hours. Accordingly, the invention in one of its possible forms is directed to a sensor enclosure which provides for selective shading of a contained light sensor and which may be adapted to accommodate near-arbitrary positioning of the enclosure relative to an artificial light source.

Thus, the present invention may be defined broadly as providing an enclosure for a light sensor or emitter and which includes a window behind which the sensor or emitter is located and a shield positioned adjacent the window.

The shield comprises a ring-like portion that surrounds the window and has a barrier portion which projects outwardly from the enclosure. The barrier portion is 15 foried integrally with the ring-like portion and the shield is rotatable about the window to a selected position at which the barrier portion functions to deflect incident light moving toward or away from the window.

The window may be open but it preferably is fitted 20 with a lens which is arranged to protect the light sensor or emitter.

The shield may be fitted to the enclosure so as to form a tight sliding (rotatable) fit relative to the enclosure, or a detent-type contact may be provided between the shield and the enclosure. In either case, it is the intention that the projecting portion of the shield will remain in any location in which it is positioned until such time as it is manually moved.

The invention will be more fully understood from the following description of a preferred embodiment of an enclosure for a light sensor, the enclosure being illustrated in the accompanying drawings in which: Figure 1 shows an exploded perspective view of a casing, a lens and a rotatable shield, and Figure 2 shows an enlarged elevation view of a closure portion of the casing, as viewed in the direction of section plane 2-2 in Figure 1.

As illustrated in the drawing, the complete sensor

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I I I' 1 13 1 i i -4 enclosure comprises a box-like casing 10 and a removable cover II which normally is fitted to the casing by screws 12. The enclosure is adapted to receive electronic components, usually mounted to a printed circuit board, and one of the components will comprise a photoelectric cell (not shown) mounted immediately below a window 13 in the cover 11 of the enclosure. Knock-out conduit entry ports 14 are located in the surrounding wall of the casing 10, to permit wiring to be directed into and from the interior of the casing.

Both the casing 10 and the cover 11 are formed from moulded plastics material.

A moulded clear or translucent lens 15 is mounted to the cover 11 and positioned to overlie the window 13.

The lens 15 is shown removed from the cover in Figure 1 of the drawings but, as indicated, the lens 15 would normally sit upon the top surface of the cover.

A moulded ring 16 is formed on the underside of the lens and it has a diameter which fits neatly within the circular groove 17 in the cover. The ring 16 functions to position the lens relative to the window 13 and it is the central region of the lens, within the ring 16, through which light passes to enter the enclosure. The lens is secured in position by ultrasonically welding the oGe...

G 25 ring 16 within the groove 17.

I :'e The groove 17 is formed within an annular moulding portion 18 that surrounds the window 13, and the annular moulding portion is itself surrounded by an annular recess 19. Also, a peripheral wall of the annular moulding portion 18 is moulded integrally with teeth-like undulations 20 that form an inner margin of the

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recess 19.

A shield 21 is mounted to the cover 11. The shield has a ring-like portion 22 which locates within the Ce 35 annular recess 19 and it further comprises an arcuately formed outer projection 23. The outer projection 23 functions as a barrier and it may be positioned around the lens selectively to shade the lens from side lighting

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r that is directed toward the enclosure from an adjacent artificial lighting source.

A radially projecting nib 24 (Figure 2) is formed within a peripheral wall 25 of the ring-like portion of the shield 21 and the nib 24 is arranged to engage with the teeth-like undulations 20 extending around the window 13. The nib 24 is arranged to engage in interfering relationship with the undulations 20, so that the outer arcuate projection 23 will be held captive in a given position in which it is located until it is rotated manually against the force exerted by the interfering nib and undulations.

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Claims

2. An enclosure for a light sensor which is intended to sense the level of ambient light, the enclosure comprising a window behind which the sensor is located and a shield positioned adjacent the window, the shield comprising a ring-like portion that surrounds the window and having a barrier portion which projects *0 outwardly from the enclosure, the barrier portion being formed integrally with the ring-like portion and the shield being rotatable about the window to a selected position at which the barrier portion functions to deflect incident light that would otherwise enter the window from S: an artificial light source located to one side of the enclosure. .o• 25 3. An enclosure as claimed in claim 1 or claim 2 i wherein the window is fitted with a transparent or translucent lens.
4. An enclosure as claimed in any one of claims 1 to 3 and wherein the barrier portion comprises an arcuately formed projection of the ring-like portion. An enclosure as claimed in any one of claims 1 to 4 wherein a nib is formed integrally with the ring-like i portion and is engageable with a teeth-like undulation that surrounds the window in order that the shield, may be positively located in a selected position. IVA K i -7-
6. An enclosure substantially as shown in the accompanying drawings and substantially as hereinbefore described with reference thereto. DATED this 28th day of November 1995 H.P.M. INDUSTRIES PTY LIMITED By their Patent Attorney GRIFFITH HACK CO A I. 44 9 4 *49 9 49 9 4 9. V 4 444944 4 4e 9~ 9 9* 44 94 9 9 4 94 44 4 *94 9 949 9 49 *4 9 994*94 I' 9 4 944*99 9 4 99 4*4 4*~ 44 9 4 *9 9* ABSTRACT An enclosure which is intended to accommodate a light sensor and which provides for selective shading of the sensor from an adjacent source of artificial light. The enclosure includes a window behind which the sensor is located and a shield positioned adjacent the window. The shield projects outwardly from the casing and is movable around the window to a position at which it functions as a barrier to deflect light moving in the direction toward the window. 9 9i V r i .1 9 1 *7 1