Light-operated Control Device

Abstract

A light-operated control device including a spherical housing mounted on a second housing for universal swiveling movement relative thereto. An arm extending out from the second housing overlies the sphere and is clamped thereagainst to secure the sphere in any selected position. A photocell mounted in the sphere has a light-sensitive side which faces out through an aperture in a side of the sphere. A light-channeling passage having deflector surfaces along its sides extends between the aperture and the light-sensitive side of the photocell. This passage inhibits ambient light from striking the photocell. The photocell is connected to control circuitry in the second housing by elongated flexible conductors which permit free swiveling of the sphere.

Description

This invention relates to a light-operated control device.

A general object of the invention is to provide a novel light-operated control device with includes a light-responsive element mounted in such a manner that it may be directed easily in any desired direction.

More specifically an object is to provide such a device wherein the light-responsive element is in a housing which is mounted for universal swiveling movement. The device also includes means for securing the housing in any selected position. The device thus permits a light-sensitive side of the element to be directed as desired and then secured in such position.

Another object is to provide such a novel light-operated control device wherein the housing in which the light-responsive element is mounted is seated on a second housing for universal swiveling movement relative thereto. The second housing holds control circuitry to which the light-responsive element may be electrically connected. With this construction the housing for the light-responsive element may be made smaller than would be possible if all control circuitry were to be mounted therein. Also, the housing mounting the control circuitry is the one used to anchor the device in an installation.

Yet another object is to provide for such a device, light-channeling means mounted adjacent the light-sensitive side of the light-responsive element. The light-channeling means provides an elongated passage with deflector surfaces along its sides, the deflector surfaces being disposed at substantial angles to the axis of the passage. This construction assures that the light-sensitive side of the element is effected primarily by light beamed directly thereagainst. The light-channeling means minimizes the effect of ambient light.

These and other objects and advantages will become more fully apparent as the following description is read in conjunction with the drawings, wherein:

FIG. 1 is perspective view of a light-operated control device constructed according to the invention;

FIG. 2 is an enlarged cross-sectional view taken generally along the line 2--2 in FIG. 1;

FIG. 3 is an exploded view of a pair of mating parts which comprise a portion of the invention; and

FIG. 4 is a simplified schematic diagram of a switching circuit in the device.

Referring now to the drawings, and first more specifically to FIG. 1, at 10 is indicated generally a light-operated control device according to the invention. The device includes a spherical housing 14 mounted on a box housing 16.

Referring first to housing 14, it includes a pair of hollow hemispheric portions 14a, 14b which are joined along their edges to form a hollow sphere. An aperture 20 is provided on one side of housing 14. As is best seen in FIG. 2, a pair of bores 22, 24 extend through housing 14, bore 22 being displaced 90.degree. from aperture 20, and bore 24 being displaced 90.degree. from bore 22 or diametrically opposite aperture 20.

Housing 16 has an opening 26 extending through its top. A rubber O-ring seal 28 rests on a lip 29 surrounding opening 26. The lip and seal provide a seat on which housing 14 rests.

A mounting bracket, indicated generally at 30, is mounted on housing 16 for securing housing 14. Bracket 30 includes a base portion 32 and a pair of curved expanses 34, collectively comprising an arm, which project upwardly from base 32 and curve over the top of housing 14. Expanses 34 converge on progressing upwardly hand have a ring 36 joined to their ends which seats on the top of housing 14. A pair of screws, such as that indicated at 38 in FIG. 2, extend through bores in base 32 and into accommodating threaded bores 40 in housing 16.

With screws 38 loosened, housing 14 is free to swivel about multiple axes to any desired position. With screws 38 tightened the ring on the mounting bracket is drawn tightly against housing 14 to secure the housing in any selected position.

In FIG. 1, it will be noted that a second pair of threaded bores 42 are provided in the top of housing 16, whereby bracket 30 may be mounted adjacent the opposite side of the housing. Since mounting bracket 30 and the seat provided on the top of housing 16 permit universal swiveling of housing 14 about multiple axes, they are referred to collectively herein as a universal mounting.

Referring now to FIG. 2, a light-responsive element, or photocell, 50 having a light-sensitive side 50a is mounted within housing 14. Photocell 50 is supported by mounting structure indicated generally at 54 in housing 14 with its side 50a directed toward aperture 20.

A photocell which has been found to work well in such a device is a cadmium selenide type, manufactured by National Semiconductors Ltd., and identified by manufacutere's number NSL-3531 and NSL-3561. These photocells each have a peak sensitivity in the red part of the spectrum (approximately 7,100 Angstroms) and thus are effected primarily by light sources in this range. If the photocell is directed at a light source producing light in this part of the spectrum its response will be affected primarily by such light source, and ambient light from artificial sources, such as flourescent or mercury vapor lamps which are generally nearer the ultraviolet part of the spectrum, will have minimal effect on the photocell.

Structure 54, as is best seen in FIG. 3, is composed of a pair of mating semicylindrical components 54a, 54b which, when mounted in housing 14, join along their flat facing surfaces. Components 54a, 54b are substantially mirror images of each other, with the exception that component 54b has multiple pins 54 extending outwardly therefrom and component 54a has accommodating bores for receiving these pins to properly align the components when fit together.

With components 54a, 54b fit tightly together to form mounting structure 54, and referring specifically to FIG. 2, they provide a socket 60 within which the photocell is firmly seated. A pair of ears 62 extend laterally outwardly from opposite sides of socket 60. These ears have notches therein which engage pins 64 which are secured to one hemispheric portion of housing 14 and project inwardly therefrom. Mounting structure 54 is firmly seated in housing 14 by being wedged between pins 64 and the left wall of housing 14 as seen in FIG. 2.

Wall structure 66 of mounting 54 defines a tunnel, or passage, 68 open at both ends, which extends forwardly, to the left in FIG. 2, from the light-sensitive side of photocell 50 to aperture 20. Annular grooves, 70 are defined in wall structure 66 opening inwardly toward passage 68. The sides of grooves 70, also referred to herein as deflector surfaces, are disposed at substantial angles to the central axis of the passage.

The passage and annular grooves defined by wall structure 66 may be filled with a translucent material which permits light to pass therethrough to the photocell. A material which has been found to work well is an elastomeric silicone rubber such as the material manufactured by General Electric under this generic name, and having a manufacturer's number RTV-108. This material provides a bond to hold components 54a, 54b together and to secure the photocell solidly in the unit. The material maintains its bond and elasticity throughout a wide temperature range, thus providing good shock protection for the photocell in any application. The material also seals out dust.

The passage and annular grooves provided by wall structure 66 act as light-channeling means which provides a course along which light directed straight through aperture 20 may pass substantially unobstructed to the light-sensitive side of the photocell. Light entering the aperture at an angle will strike one of the angularly disposed sides of the annular grooves and be reflected away from the light-sensitive side of the photocell. Thus, light entering housing 14 directly through aperture 20 will have maximum effect on side 50a while light entering the aperture at an angle will have minimum effect thereon.

A lens 74 mounted in the aperture serves to focus light more directly as its enters the housing. The lens may be made of glass, or other easily cleaned hard translucent substance, to protect the underlying elastomeric material filling the passage.

A pair of conductors 78, 80 are connected to element 50 and are shown in FIG. 2 extending out of housing 14 through bore 22 and into housing 16. This positioning of the conductors permits swiveling of housing 14 to direct side 50a of the photocell to any side and at a substantial angle to the horizontal.

Should it be desired to direct side 50a straight up, or at some small angle from the vertical, conductors 78, 80 may be extended out of housing 14 through bore 24, which bore, with the housing turned to face photocell 50 upwardly, would be in communication with opening 26 in housing 16. With the photocell directed straight up it sees through the opening in ring 36. As has been mentioned previously mounting bracket 30 may be secured to housing 16 adjacent the opposite side of the housing if it is desired to direct the photocell in a direction opposite the direction it points in the illustrations. Further, the space between expanses 34 of the bracket will be adequate in most cases for providing visual clearance for the photocell without repositioning the bracket.

Referring now to FIG. 4, a schematic of a switching circuit in the invention is illustrated generally at 90. The switching circuit, of which photocell 50 is a part, is connected between an AC power source 92 and a load 94. Control circuitry, which comprises a part of the switching circuit, is mounted within housing 16 on a terminal block indicated generally at 96 in FIG. 1 and illustrated by a dot-dash outline in FIG. 4.

The control circuit within housing 16 includes a switching element 98, comprising a bi-directional triode semiconductor, commonly known as a Triac, which is connected in series with the power source and load. The Triac is provided with first and second anodes 102, 104, respectively, and a gate electrode 106. Anode 102 is connected to the power source and anode 104 is connected to load 94. Gate electrode 106 is connected to the cathode of an avalanche diode 108. The anode of diode 108 is connected to the common juncture of a biasing capacitor 114 and conductor 80 connected to photocell 50. A filter capacitor 112 is connected in parallel with the Triac.

Wall structure 66 of mounting structure 54 is illustrated schematically in FIG. 4 adjacent photocell 50. A lamp, or light source, 120 is positioned opposite photocell 50, whereby its light is directed toward photocell 50 along a course through the passage provided by wall structure 66. As mentioned previously the light source preferably is one which emits light in the red part of the spectrum.

Describing now the operation of the light-operated control device of the invention. With screws 38 loosened, housing 14 may be swiveled as desired to direct side 50a of photocell 50 toward a light source to be monitored. With the aperture and photocell directed as desired, screws 38 are tightened to draw the mounting bracket tightly against housing 14 frictionally to hold it in its adjusted position. As has been noted previously, the light source toward which photocell 50 is directed will have maximum effect thereon, since the light from such source will have an unobstructed passage to the photocell. Light directed toward the photocell from other sources will be deflected by the sides of annular grooves 70 to minimize its effect on element 50.

The supply of electrical current from source 92 to load 94 is controlled by the switching circuit and is dependent on whether light from source 120 reaches photocell 50 or is blocked from the photocell. Such control function is described in detail in the previously mentioned copending application.

If it becomes necessary to monitor the operation of a light source at another location, it is a simple matter to readjust the position of housing 14 to direct the light-sensitive side of photocell 50 toward the new light source to be monitored.

While an embodiment of the invention has been described herein, it should be obvious to those skilled in the art that variations and modifications are possible without departing from the spirit of the invention.

Claims

It is claimed and desired to secure by Letters Patent:

1. A light-operated control device comprising

a substantially spherical first housing,

an aperture extending through a side of said housing through which light may enter the housing,

a light-responsive element mounted on said housing positioned to receive light entering the housing through said aperture,

a second housing,

control circuitry mounted in said second housing,

mounting means mounting said first housing outwardly of a side of said second housing for universal swiveling movement relative to said second housing between multiple adjusted positions with the light-responsive element facing in different directions in said adjusted positions, said mounting means including means defining a seat on said side of said second housing receiving a side portion of said first housing, and an arm mounted on and projecting outwardly from the second housing having an engaging portion forming a seat which receives another side portion of the first housing which other side portion is diametrically opposite the first-mentioned side portion of the first housing, said light-responsive element facing to one side of said first-mentioned and other side portions of the first housing,

adjustable means for releasably clamping said seats against said first housing frictionally to secure the first housing relative to said second housing in a selected adjusted position, and

means electrically interconnecting said light-responsive element and said control circuitry and accommodating such universal swiveling movement of the first housing relative to the second housing.