Security System

Abstract

An electrooptical intruder detection system including alignable emitting and detecting elements, such as semiconductor diodes. Each element is disposed in a holder member having a semispherical head portion which cooperates with a mounting plate and retainer member to provide the alignment function. In addition, the emitting element may be mounted in an adapter member which is axially adjustable relative to the holder member. Installation in an electrical outlet having various apertures for exposing the electrooptical element and permitting connection to external electrical devices is preferred.

Description

This invention relates to security systems of the type having a transmitter and a receiver disposed in signal transfer relation along a predetermined line of sight and, more particularly, to such a security system which includes improved apparatus for concealing and aligning the various elements thereof for optimum signal transfer.

Copending application for patent, Ser. No. 816,727, filed in the name of David R. Matthews, discloses a security system employing an electro-optical pulse transmitter and an electro-optical receiver disposed in signal transfer relation such that the presence of an intruder in the line of sight between the transmitter and receiver results in the loss of pulses at the receiver. The loss of a predetermined number of such pulses produces an alarm signal indicating the presence of an intruder. In many instances it is highly desirable to conceal the transmitter and receiver apparatus of such a system by inconspicuous appearance and, further, to provide convenient means by which the transmitter and receiver can be aligned with the predetermined line of sight to provide optimum signal transfer and system performance under various conditions. The present invention is particularly suited to satisfy such objectives.

In accordance with the present invention, a security system such as that described in the aforementioned copending application or any similar system employing a defined signal beam may be aligned for optimum signal transfer along a predetermined line of sight. In general, this is accomplished by the provision of a holder member for an electro-optical element, such as a diode, together with mounting means for permitting the alignment of the holder member with the line of sight.

In a preferred form, the holder member comprises a hollow cylindrical member having a head portion carrying the electro-optical element adjacent an aperture defining a signal path and a mounting plate having a portion for retainingly receiving the head portion of the holder member in variably alignable engagement therewith. This apparatus may be used in either the transmitter or the receiver, but preferably in both, and permits the various electronic packages which, in themselves, require no alignment, to be mounted separately from the electro-optical elements and the associated holder members.

In accordance with the invention the holder member may be easily concealed such that only the aperture in the head portion is exposed. In a preferred embodiment, the mounting plate for the holder member takes the form of a common electrical outlet having various apertures for receiving plug prongs and ground prongs. Such an arrangement not only permits concealment of the holder within the outlet but also facilitates the electrical connection of apparatus such as external power supplies and meters to the electronic packages through the apertures of the electrical outlet.

The invention, as well as the various features and advantages thereof, may be best understood by reference to the following description of an illustrative embodiment. This description is to be taken with the accompanying drawings of which:

FIG. 1 is a schematic diagram of a typical security system which may employ the invention;

FIG. 2 is a plan view of a mounting structure in the form of an electrical outlet;

FIG. 3 is a side view in cross section of a preferred mounting structure;

FIG. 4 is a block diagram indicating the preferred connection pattern of the receiver apparatus; and

FIG. 5 is a side view in cross section of a preferred holder assembly.

FIG. 1 illustrates a security system including an infrared pulse signal transmitter 10 for directing signals toward an electro-optical receiver 12 along a line of sight defined by the indicated "optical path." Transmitter 10 includes an electro-optical signal emitter such as a gallium arsenide diode disposed in a holder member 16 and electrically connected to a pulser 18 such as a multivibrator or a relaxation oscillator. Pulser 18 is connected to a DC power supply 20 and supplies a continuous train of narrow current pulses to the electro-optical emitting element for the generation of optical pulses in the infrared frequency range. Holder 16 is disposed in mounting apparatus including the combination of a plate 22 having an aperture 23 which engages the holder 16 in such a fashion as to permit various angular orientations and alignment of the holder 16 with the line of sight to the receiver 12. The mounting apparatus further includes a retainer member 24 which also engages the holder 16 to maintain it in engagement with the plate 22.

Receiver 12 includes an electro-optical element, such as a silicon diode, disposed in a holder 26 so as to be responsive to the optical signals from transmitter 10 to produce a varying electrical signal. This signal is coupled to amplifier 28 which receives power from DC source 30. The amplified receiver signals are connected into a signal processor and alarm device 32 which responds to the absence of receiver pulses for a given interval to produce an alarm signal. Holder 26, which is generally similar to transmitter holder 16, is mounted in a plate 34 having an aperture 35 which receives and engages the holder 26 and permits alignment thereof with the optical path of the signal from transmitter holder 16. Holder 26 is maintained in engagement with plate 34 by a retainer member 36.

FIG. 5 illustrates in detail the construction of the transmitter holder 16. Holder 16 is of generally cylindrical configuration and includes a hollow head portion 38 of semispherical internal configuration and a tubular body portion 40. Head portion 38 includes an axially aligned cavity 42 within which is disposed a planar gallium arsenide diode 44 preferably, but not necessarily, of the nonlasing type. Cavity 42 terminates at the forward boundary of head portion 38 in an aperture within which is disposed a convex lens 46 for collimating the infrared signals produced by the diode emitting element 44. The tubular body portion 40 includes an internally threaded neck portion 48 which receives an externally threaded adapter member 50 of cylindrical configuration in axially adjustable engagement therewith. The emitting diode element 44 is soldered or otherwise suitably secured to the end portion of the adapter member 50 so as to be within cavity 42. Adapter 50 is axially adjustable in its relationship with holder 16 to permit precise location of the emitting element 44 at the focal point of lens 46. Emitter element 44 is electrically connected to an insulated conductor 52 which in turn is connected to the pulser 18 as shown in FIG. 1. A second insulated lead 54 is connected to the electrically conductive body of adapter member 50 and also extends to the pulser 18 as shown in FIG. 1. The holder 16 is preferably constructed of a phenolic material so as to be electrically insulative.

The receiver holder 26 may also be constructed in the manner shown in FIG. 5 but, as a practical matter, need not be provided with the adjustable adapter member 50. Rather, the infrared signal-responsive element of the receiver holder 26 may be permanently secured within the cavity since precise focusing in the receiver portions is not required.

FIGS. 2 and 3 illustrate a preferred form of the mounting elements for both the transmitter and receiver holder members, but will be described with particular reference to the receiver 12, it being understood that a similar structure may be employed in the transmitter 10. Mounting plate 34 is constructed in the form of a commonplace electrical wall outlet having an upper double prong receptacle 56 and a lower double prong receptacle 58. The upper receptacle 56 includes a pair of plug prong receptacles 60 and a ground prong receptacle 62 disposed in the ordinary physical relationship to one another. Similarly, the lower receptacle 58 includes a pair of plug prong apertures 64 and a ground prong aperture 66. The plug prong apertures 60 and 64 may be internally modified to accept only a plug of specified configuration thereby to prevent the inadvertent admission of a standard plug for some commonplace electrical appliance.

As best shown in FIG. 3, the ground prong aperture 62 is contiguous with and axially aligned with a semispherical socket portion 68 which extends through the rear surface of the plate 34 to receive the head portion 70 of the receiver holder member 26. Head portion 70 is also of semispherical configuration and carries a lens 72 in the forward portion thereof in the same manner as the transmitter holder 16 described with reference to FIG. 5. Universal movement is permitted between head portion 70 and the socket portion 68 of the plate 34 to accomplish the alignment function. To maintain the holder 26 in the desired position a retainer member 36 is suitably adapted for interconnection with the plate 34 and includes an aperture 74 of semispherical configuration to engage and retain the rear of the head portion 70 of holder member 26 as shown in FIG. 3.

By installing the transmitter holder member 16 and the receiver holder member 26 in the mounting structure described in FIGS. 2 and 3, a universal type swiveling action is permitted between the head portions of the holder members and the engaging mounting structure to permit axial alignment of the two holder members and the two electro-optical elements associated therewith in a common line of sight. Moreover, the transmitter member 16 further permits a precise focusing of the optical signals into a collimated beam which then may be directed toward the receiver element. Since the holder members 16 and 26 are physically separate from their associated electronics modules, as shown in FIG. 1, the alignment function is facilitated and the space within which the alignable elements are disposed may be held to a minimum.

FIG. 4 illustrates a receiver installation which facilitates concealment, access, and operation of the system. The amplifier 28 and signal processor and alarm device 32 are shown disposed within an electrical outlet box 76 of the type which may be conveniently installed in any wall. Receiver holder member 26 is disposed in the upper receptacle 56 of the double outlet plate 34 and retained in position by the retainer member 36 in the manner described with reference to FIGS. 2 and 3. Optical signals are thus received by the silicon diode disposed within holder member 26 through the ground prong aperture 62 and the exposed lens 72. Electrical signals produced by the detector diode are coupled into amplifier 28 through electrical conductors 78 and thence to the signal processor and alarm device 32 through conductors 88. Power supply 30 is connected to the amplifier 28 and the processor alarm 32 through a cord 80 and plug 82 of the double prong type which is conveniently inserted into the plug prong apertures 64 of the lower receptacle 58. The plug prong apertures 64 may be provided with suitable conductor means including lines 84 for connection to the amplifier 28, and lines 86 to the processor-alarm 32. Power supply 30 may be concealed in a common electrical appliance such as a lamp base to thereby assume an inconspicuous appearance. Upon initial installation of the system and from time to time during the operation of the system, it may be desirable to realign the receiver holder member 26 with the transmitter holder member 16. This may be readily accomplished by removal of a cover plate 90 to allow access to the apparatus within the box 76. A meter 92 may be provided with a plug 94 having a pair of prongs which are received by the plug prong apertures 60 of the upper outlet portion 56. The interior of the apertures 60 are connected by means of electrical conductors 96 to an output of amplifier 28 to monitor the amplitude of the electrical signal produced by the amplifier. In the alignment process the transmitter pulser 18 is turned on to direct pulses toward the receiver holder member 26. The receiver and holder members are varied in alignment until a peak reading is obtained on meter 92. At this point, the receiver holder members are suitably aligned and the cover plate 90 may be reinstalled after disconnecting the meter plug 94 from the upper outlet portion 56.

Although the invention has been described with reference to a specific embodiment, it is to be understood that the invention is not to be limited thereby.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In a security system of the type having a signal transmitter and a signal receiver alignable in signal transfer relation along a common line of sight; a transmitter device comprising a holder member having a generally spherical and hollow head portion and a shank portion integral therewith, an electrically actuable radiant energy emitter in the head portion, a support plate having a socket therein to adjustably receive the head portion, and a retainer member engageable with the plate and the head portion to maintain the head portion in engagement with the socket to permit substantially universal adjustment of the holder to establish said line of sight, a lens disposed in the head portion such that radiant energy from the emitter passes therethrough, the plate including a pair of apparent plug prong apertures and an apparent ground prong aperture arranged to appear as an electrical wall outlet, said socket being contiguous with the ground prong apertures such that the line of sight extends therethrough.

2. Apparatus as defined in claim 1 including an adapter member axially adjustably disposed within the shank portion and carrying the emitter to permit adjustment in the spacing between the emitter and lens.

3. Apparatus as defined in claim 1 wherein the emitter is a diode.

4. In a security system; a transmitter device for transmitting a radiant energy beam and a receiver device in the path of the beam for receiving the beam and indicating an interruption thereof, mounting means for at least one of the devices including a plate having first and second pairs of parallel apparent prong apertures and first and second apparent ground prong apertures therein to appear as an electrical wall outlet, said one device being adjustably supported by the plate such that the beam path extends through one of the ground prong apertures thereto.

5. Apparatus as defined in claim 4 wherein said one device is a receiver device, the combination further including signal processing means electrically connected to said receiving device for producing signals indicating the interruption of the beam directed thereto.

6. Apparatus as defined in claim 5 including a power supply having a double-prong plug for insertion in one of said first and second pairs of parallel prong apertures, and electrical connector means connecting said apertures to said one device.

7. Apparatus as defined in claim 6 including monitoring means and electrical connector means for connecting the monitor means through one of said first and second pairs of said parallel prong apertures to said signal processing means.

8. Apparatus as defined in claim 4 wherein said one device is a photoelectric device and means mounting said photoelectric device to said plate for permitting limited universal adjustment in the viewing direction thereof.

9. Apparatus as defined in claim 8 wherein said means for permitting universal adjustment includes a spherical shaped holder carrying said photoelectric device and means including a portion of said plate defining a socket for receiving said spherical holder.

10. Apparatus as defined in claim 9 wherein said holder includes a lens alignable with said ground prong aperture so as to lie in the beam path, and means for adjusting the axial distance between said photoelectric device and the lens for focusing purposes.