Title:
ANNUNCIATOR WITH TIMED ILLUMINATION MEANS
United States Patent 3648273


Abstract:
An annunciator control system is provided having a momentary-on pushbutton switch to activate a doorbell, chimes or other audio signal means and a delay means to provide electric current to an illuminating device for a predetermined period of time after the switch is depressed. The illuminating means may be an ordinary incandescent lamp located in the pushbutton switch housing to illuminate the person activating the device or it may be a remotely located lamp such as an entrance way lighting fixture to illuminate the entrance for a fixed period of time after the system is activated.



Inventors:
GARDNER DONALD J
Application Number:
05/064344
Publication Date:
03/07/1972
Filing Date:
08/17/1970
Assignee:
DONALD J. GARDNER
Primary Class:
Other Classes:
337/88
International Classes:
G08B5/36; H01H43/30; (IPC1-7): G08B27/00
Field of Search:
337/376,88,107,64,68,100,104,120,77 219
View Patent Images:
US Patent References:
3150361Mail indicator and door signal1964-09-22Conigliaro
3135953Lamp illuminating network1964-06-02Bagno
3084237Electrical apparatus1963-04-02Mentzer
2935588Electrical delay switch1960-05-03Slater
2801313Time delayed switch1957-07-30Reynolds
2697765Power interrupter for electrical appliances1954-12-21Little
2439766Audible and visual electrical signaling device1948-04-13Weissman
2259758Timing device for electric circuit operation1941-10-21Luce
1828321Circuit control1931-10-20Hesse



Primary Examiner:
Broome, Harold
Claims:
I claim

1. An annunciator system, comprising: an electrically driven audio signal means, a normally open pushbutton switch means for selectively connecting said audio signal means to a source of electrical power, a thermistor electrically connected to the normally unenergized terminal of said switch means and in shunt relationship to said audio signal means, and a bimetallic heat responsive switch connected to said thermistor and responsive to said thermistor to complete an electrical circuit when heated after said switch member is closed and which will maintain the circuit closed while heated.

2. In an annunciator system as defined in claim 1 and further including, a nonconductive housing mounting said switch means, a light-permeable cover on at least a portion of said housing and electrical illumination means in said housing adjacent to said cover and operable when said heat-responsive switch is closed for emitting radiant energy.

3. In an annunciator system as defined in claim 2, said pushbutton switch member comprising a first contact formed from a flat conductive spring secured at one end to said housing, a manually actuable switch actuator extending through said cover and adapted to deflect said first contact, a second contact formed from a flat conductive spring secured at one end to said housing, the other end of said second contact being normally spaced from but within the path of movement of said first contact and being engageable therewith when the same is deflected thereby completing a circuit through said thermistor and said audio signal means.

4. In an annunciator system as defined in claim 2 and further including a reflector secured in said housing adjacent said illumination means for reflecting light toward and through said cover.

5. In an annunciator system as defined in claim 1, and further including a nonconductive housing mounting said switch means, and electrical illumination means remote from said housing and electrically connected to said switch means and operable when said heat-responsive switch is closed.

6. In an annunciator system as defined in claim 1, and further including, a nonconductive housing mounting said switch means, a cover on said housing, said pushbutton switch member comprising a flat conductive spring member secured at one end to said housing, the other end thereof being bifurcated forming a first and second contact arm, a manually actuable switch actuator extending through said cover and adapted to deflect said first and second contact arms, a third contact formed from a flat conductive spring secured at one end to said housing, the other end of said third contact being normally spaced from but within the path of movement of said first contact arm and being engageable therewith when the same is deflected thereby completing a circuit through said audio signal means, and a conductive strip mechanically and electrically secured to one terminal of said thermistor, said bimetallic switch being mechanically and electrically secured to the other terminal of said thermistor, said strip being mechanically but not electrically connected to said bimetallic switch and being engageable by said second contact arm during deflection thereof only when the bimetallic switch is in an unheated condition, thereby completing a circuit through said thermistor.

7. In an annunciator system as defined in claim 6 and further including; an electrical illumination means in said housing adjacent to said cover and operable when said heat-responsive switch is closed for emitting radiant energy, and a light-permeable section in said cover adjacent to said illuminating means.

8. In an annunciator system as defined in claim 7 and further including a reflector secured in said housing adjacent to said illumination means for reflecting light toward and through said cover.

9. In an annunciator system as defined in claim 6, and further including an electrical illumination means remote from said housing and electrically connected to said switch means and operable when said heat responsive switch is closed.

10. In an annunciator system as defined in claim 6 and further including, a conductive cam secured to said second contact arm for engaging said conductive strip when said second contact arm is depressed, a cam surface formed on said conductive cam adapted to deflect said conductive strip and close said bimetalic switch, and a detent formed in said cam surface adapted to cooperate with said conductive strip to hold same cam in a position maintaining deflection of said conductive strip and closure of said bimetalic switch until said bimetalic switch heats sufficiently to disengage said conductive strip from said detent.

Description:
This invention relates to improvements in annunciator systems such as doorbells or chimes of the type primarily used in residential dwellings. It comprises a combination of a doorbell switch, thermal delay switching means, lamp circuitry, and a thermistor to activate the thermal delay switch.

Prior art devices merely activate a bell or chime, or in the case of the patent to WEISSMAN, U.S. Pat. No. 2,439,766, activate a lamp as long as the pushbutton is depressed. When the prior art systems are activated at night the occupant of the dwelling cannot normally tell who is at the entrance unless he turns on an exterior lamp, or in the case of an annunciator used to signal deaf or partially deaf persons, the signal is usually so brief due to being activated only while the button is depressed that it is often not noticed by the occupant.

One objective of this invention is to overcome the above deficiencies of prior art annunciator systems by providing a time delay means associated with the pushbutton switch which will provide current to an illuminating means for a predetermined period of time and thereby illuminate the person activating the system for a duration of time sufficient for the occupant to identify who is at the door. Such system provides security to the homeowner from unwanted callers and possible intruders.

Another object of the present invention is to provide a visual signal inside a residence for a predetermined period of time after the system is activated to enable sufficient time for an occupant to recognize the signal.

A further object of this invention is to provide an annunciator activation switch readily adaptable to currently installed annunciator systems which will provide current to existing illuminating means for a predetermined duration of time after the system is activated.

Another objective of the present invention is to provide an annunciator activation switch readily adaptable to currently installed annunciator systems wherein the switch housing contains a lamp controlled by a time delay means to illuminate the area in front of the switch for a predetermined length of time after the switch is depressed.

A further objective of the subject invention is to provide an annunciator activation system which is readily adaptable to existing annunciator systems and is simple to install.

Another objective of the subject invention is to provide an annunciator activation system which provides the foregoing improvements and is efficient, reliable, and economical to manufacture and to install.

In the drawings:

FIG. 1, is a circuit diagram of an annunciator system in combination with the time delay and illuminating means of this invention;

FIG. 2, is a cross section through the side of the switch housing of one embodiment of this invention revealing the momentary-on activation switch, time delay means and illuminating means and schematically illustrating the interconnection between the power source and an audio signal means;

FIG. 3, is a cross section through the top of the switch housing illustrated in FIG. 2;

FIG. 4, is a section through a portion of the switch housing assembly showing a second embodiment of the invention wherein the illuminating means is remotely located;

FIG. 5, is a top cross section of an alternate embodiment of the switch assembly incorporating a modified activation and time delay switching means affording protection against overheating of the thermistor;

FIG. 6, is a side cross-sectional view of the switch assembly embodiment illustrated in FIG. 5;

FIG. 7, is a top cross section of an alternate embodiment of the switch assembly incorporating a modified activation and time delay switching means affording instant on operation of the illuminating means and increasing the duration of time the illuminating means will be energized;

FIG. 8, is a side view of the latching cam incorporated in the embodiment illustrated in FIG. 7; and

FIG. 9, is a front view of the latching cam incorporated in the embodiment illustrated in FIG. 7.

Considering the drawings in more detail, the schematic of FIG. 1 illustrates the functional aspects of the invention. In the preferred embodiment of the invention current is supplied from the normal residential electrical power source 10 to a stepdown transformer 11 and bell or chime 12 as in the normal residential annunciator or doorbell system. Momentary-on pushbutton switch 13 is used to control current flow between the secondary 14 of the transformer 11 and the activation coil 15 of the aduio signaling device 12. A thermistor 16 is provided in parallel with the coil 15 of the audio signaling device so that current will flow through the thermistor when the pushbutton 13 is depressed. The heat generated by electric current flow through the thermistor 16 causes bimetal switch arm 17 to deflect and close a circuit at contact 18. This provides a path for current from the transformer 11 through a lamp 19, bypassing the pushbutton switch 13. Therefore, when the system is activated, the lamp will remain illuminated after the pushbutton is released and will remain activated until such time that the bimetal switch arm cools sufficiently to move away from contact 18.

FIG. 2 illustrates one embodiment of the invention wherein the components comprising the improvements are contained within a switch housing 20. The switch housing may be fabricated from a nonconducting material such as plastic and is in the shape of a rectangular box open on the top side. A recess 21 is formed about the inner periphery of the open side of the box to receive a translucent cover plate 22. The translucent cover plate 22 has a bore 23 formed in it to receive the momentary-on pushbutton switch activation rod 24. The switch activation rod 24 has an enlargement 25 formed on one end to retain the pushbutton activating rod within the switch housing assembly 20. If desired, a grommet 26 may be provided in the bore 23 of the translucent cover plate 22 to provide a longer bearing surface against the side of the activating rod to ensure that it will not twist in the assembly. Located directly below the pushbutton activating rod is a J-shaped spring contact 30 which mates with L-shaped spring contact 31 when the activating rod 24 is depressed to form the pushbutton contact 13 of FIG. 1. Normally the spring contact arm 30 bears against the bottom of the activating rod 24 to hold it firmly in the grommet 26 provided in the cover plate 22. The opposite end of this spring contact 30 is secured to the switch housing bottom panel 33 by a hollow rivet 34 having a threaded bore through the center for receiving a wire-retaining screw 35. Spring contact 31 is similarly fastened to the bottom panel 33 of the switch housing 20 by a hollow threaded rivet 36 and wire-retaining screw 37. The thermistor 16 and bimetal element 17 are secured in the switch housing by an L-shaped bracket 40 which is secured to the bottom panel 33 of the switch housing 20 by a hollow threaded rivet 41 and wire retaining screw 42. The thermistor 16, bimetal element 17 and L-shaped bracket 40 are assembled together by a screw 43 passing through a bore in all three elements and retained by a nut 44 (see FIG. 3). Delay switch contact 18 is secured to the switch housing lower panel 33 by a screw 45 which passes through a bore in the bottom panel to engage threads formed in a bore through hollow delay contact 18. The lamp 19 is retained in the switch housing by reflector 46 which as a tab 47 formed thereon to retain the lamp socket 48 therein. The lamp socket 48 is a standard type having two electrical terminals. The reflector 46 is secured to the bottom panel 33 of the switch housing 20 by one or more rivets 49.

In the embodiment illustrated in FIGS. 2 and 3 the electrical connection between delay contact 18 and one terminal of the lamp base 48 is provided by an internal wire 50 and the connection between the lamp 19 and spring contact 31 is provided by an internal wire 51 connected between the other terminal of the lamp base 48 and river 34. The electrical contact between thermistor 16 and spring contact 30 is provided by an internal wire 53 connected between rivet 34 and a terminal means 54 secured to the thermistor by nut 44 but insulated from the nut 44 and screw 43 by an insulating sleeve 55 passing through the center of the thermistor and an insulating washer 56. The stepdown transformer 11 is connected to the switch assembly via wire-retaining screws 37 and 42 and the audio signaling means 12 is connected to the switch assembly via wire-retaining screws 35 and 42.

FIG. 4 illustrates an alternate embodiment of the switch assembly wherein a remotely located lamp 60 such as a porch or hall light is connected to terminal 18 via screw 45 and to spring contact 31 via retaining screw 37. In this embodiment, the internal lamp 19 may or may not be incorporated.

FIGS. 5 and 6 depict another alternate embodiment of the components contained within the switch housing comprising improvements which, in the event an operator holds the pushbutton switch 13 depressed for an excessive period of time, will prevent thermistor 16 from overheating. In this embodiment, spring contact 30 is replaced with spring contact 61 composed of a single piece of flat conductive metal spring similar to 30 except the contact end is bifurcated to form two arms, 62 and 63. Contact arm 62 serves the same function as contact arm 30 in the previously defined embodiment whereas contact arm 63 completes the circuit through thermistor 16 via the conductor 64 which is attached to the end of the bimetal element 17 via a nonconductive support means 65 such that as thermistor 16 heats, it causes the bimetal 17 to deflect and close contact 18 the energizing current for thermistor 16 is thereby removed due to the deflection of the bimetal away from contact arm 63 even though contact arm 63 is held depressed. Contact arm 63 is formed so that it is below contact arm 62 due to the relative relationship between contacts 31 and 64. The difference in position between contact 62 and 63 and the pushbutton activation rod 24 is eliminated by the screw 66 which is threaded through a tapped bore in contact arm 63 such that the activation rod 24 will contact switch arm 62 simultaneously with extension screw 66. In this embodiment contact 64 replaces the electrical connection formed by wire 53 in the previous embodiment and terminal 54 is not used. However, the insulating sleeve 55 and insulating washer 56 are retained to provide electrical insulation between contact arm 64 and screw 43 and nut 44. It should be noted that FIG. 5 illustrates the bimetal in a partially deflected position. When the bimetal is cool, the end of contact 64 through which the insulated retainer 65 passes is located directly beneath spring contact arm 63. When sufficiently heated, the bimetal element 17 is flexed against contact 18. In this embodiment of the invention an external lamp 60 and/or internal lamp 19 may be incorporated as previously described.

FIG. 7 depicts a further improvement of an alternate embodiment of the structure illustrated in FIGS. 5 and 6 which eliminates the necessity of holding the pushbutton switch 13 depressed until the bimetal element 17 is heated sufficiently to close contact 18. This improvement consists of the addition of a latching cam 67 depicted in FIGS. 8 and 9.

The latching cam 67 is constructed of a conductive material and has a threaded bore along the longitudinal axis for receiving screw 66 such that it will be mechanically and electrically fastened to the pushbutton side of contact arm 63. The latching cam 67 is cylindrical at the end adjacent to contact arm 63 and of a diameter equal to the width of the contact arm. A tapered protrusion 68 extends from one side of the latching cam body and forms a cam surface which has a detent 69 having a flat surface 73 perpendicular to the longitudinal axis of the latching cam defining a shoulder. The radius 74 of the protrusion 68 above the detent 69 is constant and greater than the radius at the base of the protrusion.

In this embodiment contact arm 63 is positioned relative to contact arm 64 such that when the pushbutton 13 is depressed the lower section of the cam surface 68 engages contact 64, completing the electrical circuit between contact arm 63 and the thermistor 16 as previously discussed. The slope of the cam surface 68 below the detent 69 is dimensioned such that as the pushbutton moves down, the latching cam 67 forces contact 64 and the bimetal element 17 toward contact 18. The bimetal element 17 engages contact 18 when the cam surface 68 has partially traversed contact 64. As the latching cam 67 continues to move down the side of contact 64 it causes contact 64 and the bimetal element to flex so that as the detent 69 of the latching cam 67 passes below contact 64, contact 64 slides across the flat surface 73 due to spring tension of the bimetalic element 17. The interaction of the spring tension of contact arm 63 and bimetalic element 17 holds the latching cam 67 in the depressed position when the pushbutton 13 is released. The radius 74 is dimensioned to hold bimetalic element 17 in contact with contact 18 when the latching cam 67 is in the latched position, ensuring that the circuit at contact 18 remains closed until the bimetalic element 17 is heated sufficiently to cause closure of the circuit due to thermal action of the switch. As the bimetal element 17 heats it flexes away from the latching cam 67 and draws contact 64 over the flat surface 73 and out of the detent 69, releasing the latching cam 67 which returns to the normally off position due to the spring action of contact arm 63. This opens the circuit to the thermistor 17, activating the time delay feature of the switch assembly. This embodiment causes the bimetalic element 17 to reach a greater temperature and thus increases the amount of delay.