US 3641545 A
A device having neon lamps for indicating an interruption of AC service. One of the neon lamps remains to be dark for the initial service period prior to an interruption and also for the subsequent interruption period, but it automatically begins to flicker in a predetermined cycle upon the resumption of service following the interruption. If necessary, another neon lamp adapted to be lighted up only for the period of the initial service may be utilized as the pilot lamp for indicating the initial service period. The distinguishment of the initial service period from the resumed service period is undertaken by an impedance-retaining circuit which utilizes a combination of a photoconductive element and a neon lamp.
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Description (OCR text may contain errors)
United States Paten Okada 5] Feb. 8, 1972  DEVICE Eon INDICATING INTERRUPTED ELECTRIC SERVICE 21 1- App]. No.: 881,711
30] Foreign Application Priority om Dec. 9, 1968 Japan ..43/l07246  US. Cl. ..340/248 B, 58/26 A, 58/152 H  Int. Cl. ..G08b 21/00  Field of Search .340/248 B, 253 C, 251, 228 S; 331/129, 130, 131; 328/148; 58/26, 26 A, 26 8,152 F, 152 H  References Cited UNITED STATES PATENTS 1,788,] 11 1/193] Knowles .34O/228 S 2,081,450 5/1937 Elliot ..58/26 A 3,311,779 3/1967 Hartkom, Jr. ..340/25l X Primary ExaminerDonald J. Yusko Assistant Examiner-Daniel Myer Attorney-Otto John Munz  ABSTRACT A device having neon lamps for indicating an interruption of AC service. One of the neon lamps remains to be dark for the initial service period prior to an interruption and also for the subsequent interruption period, but it automatically begins to flicker in a predetermined cycle upon the resumption of service following the interruption. If necessary, another neon lamp adapted to be lighted up only for the period of the initial service may be utilized as the pilot lamp for indicating the initial service period. The distinguishment of the initial service period from the resumed service period is undertaken by an impedance-retaining circuit which utilizes a combination of a photoconductive element and a neon lamp.
6 Claims, 4 Drawing Figures SHEET 1 0F 2 FIG.
W; W I d w m km b a 11:7/4 E M 2 MW R W r M W [m M 3 4 M /V INVENTOR O K A D A TAKAAKI A'UTORNEY PATENTEUFEB 8 I972 SHEET 2 OF 2 TO POINT b FIG.
TO POINT b' INVENTOR 'IAKAAKI OKADA ATTORNEY DEVICE FOR INDICATING INTERRUPTED ELECTRIC SERVICE BACKGROUND OF THE INVENTION The present invention is concerned with an indicating device, and more particularly, it relates to a device for indicating an interrupted service, intended to inform its user of the last interruption of service by'the flickering neon lamp which is started upon the resumption of service following the interrupted service. Description of the prior art:
Many of AC electrical machines and apparatuses, such as certain electric clocks, are provided with an accessory device which is adapted to indicate, by the difference in color of portions of an indicating member thereof, the last interruption of service, to enable the user to adjust or correct time of the clock. Such a device comprises an electromagnet which is capable of only retaining an armature attracted thereto and an actuating member coupled to said armature which is normally urged, by a spring means, to the position in which the armature is out of contact with the electromagnet. One end portion of said actuating member which is coupled to the annature for integral revolution therewith is of regions painted in a blue color and a red color. Arrangement is provided so that, as the actuating member is rotated as a result of either the contacting or the noncontacting state of said armature with the electromagnet, either one of the colored end portions of the actuating member is adapted to be viewed through an indicator window provided in the panel face of the device. Therefore, by manually bringing the armature into contact with the electromagnet during the initial service period prior to an interrupted service, the electromagnet will continuously retain the armature in its state of being attracted to the electromagnet without the need of a further application of manual 'force thereto. During this state of the actuating member contacting the electromagnet, the blue-colored region of the end portion of the actuating member is adapted to be viewed through the indicator window. On the other hand, during the noncontacting state of the armature, that is to say, in case the armature has returned to its normal noncontacting state by a spring means either during the period of interrupted service or during the subsequent resumed service, the red-colored region of the actuating member can be viewed through the window. Thus, the user of this device is able to know either that the service has been interrupted or that the service is resumed following an interruption.
Conventional devices of this type, however, were of the disadvantages and inconveniences that it was difficult to produce them in compact size because a large number of parts were required for the construction of such a device and that the application of a considerably large operating current was necessary because of the use of an electromagnet. Besides, giving out the information of interrupted service by merely relying on a certain color of an actuating member did not provide a strong warning to the user of the device, and accordingly, these devices of the prior art had also the drawback that the user frequently failed to become aware of the interrupted service.
SUMMARY OF THE INVENTION It is, therefore, a general object of the present invention is to provide a device for indicating an interrupted service which is capable of giving the user a most strong visual warning on the fact that there has occurred an interruption of service, as a neon l'amp starts to flicker upon the resumption of service following the last interruption.
An important object of the present invention is to provide an arrangement of electrical circuit which is operative in such a way that the neon lamp will not give out flickering signals for the initial service period prior to an interruption but will automatically begin to flicker with a predetermined cycle upon the resumption of service following the last interruption and which requires only a small operating current and accordingly will consume only a small amount of power.
Another object of the present invention is to provide an impedance retaining or changeover means containing a photoconductive element and neon lamps, which is capable of distinguishing the period of the initial service from the period of resumed service following an interruption.
Still another object of the present invention is to provide various modified arrangements of the aforesaid impedance retaining or changeover means.
A more perfect understanding of the present invention will be obtained by reading the following detailed description and the various embodiments hereinafter to be described when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a circuit diagram showing an embodiment of the present invention;
FIGS. 2 and 3 are explanatory illustrations partly in section, showing modified examples, respectively, of the block labeled 12 which is given in FIG. 1; and
FIG. 4 is a circuit diagram provided with a still another modified example of the block labeled 12 which is given in FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS In Fig. l, the block labeled 10 represents a rectifier circuit using a half-wave rectifier. The block labeled 11 represents a flicker circuit using a neon lamp. The block labeled 12, on the other hand, represents an impedance retaining or changeover network, and, stating in a more plain language, it shows a circuit provided between the points b and b for bypassing the AC current. An input is adapted to be applied through the terminals a and a which are derived from the foregoing respective circuits. In order to explain the behavior of the circuits composed of the combination of only the blocks 10 and 11, let us now assume an arrangement in which the impedance retaining network 12 in Fig. l is removed from the points b and b. With this arrangement, it will be understood that, when an AC voltage for service is applied between the input terminals a and a or to the service entrance, a DC current I having a pulselike waveform and having been rectified by a diode D will charge the capacitor C via a timing resistor R1. Since a neon lamp L1 is connected in parallel with this capacitor C, the lamp L1 is caused to discharge and luminesce at the time when the voltage Vc across the capacitor C has reached the firing voltage of the lamp Ll. whereupon, the voltage Vc instantly drops below the extinction voltage and the lamp Ll ceases discharging. This cessation of discharge signifies that the lamp L1 is in the noncharged state, or in other words, it means that the lamp is in the state in which there is a very large impedance between the electrodes thereof. The capaci tor C will be charged again up to the level of firing voltage via the resistor R1. Whereby, the neon lamp L1 is caused to luminesce with a certain cycle which is determined by the time constant RIC. Such a behavior of the circuits will be repeated so long as the application of the AC voltage for service between the input terminals a and a is continued, and accordingly, the lamp L1 is caused to flicker. More briefly, the circuits of blocks 10 and 11 constitute a relaxation oscillation circuit.
As stated above, so long as the terminals b and b are retained to be open relative to each other, the neon lamp Ll will continue to flicker with a cycle which is controlled by the timing resistor R1 and the capacitor C. This means that the neon lamp L1 will likewise flicker also when the terminals b and b are connected together and have therebetween an impedance of a very large value. This is because of the conception that an insertion of a very large resistance between the terminals b and b is substantially equal in function to the instance in which these terminals are open.
Reference is now made to the impedance retaining means or network 12. It will be noted that, in this network, a switch 5 SW is connected in parallel with a photoconductive element Rx which, in turn, is connected in series with a neon lamp L2. Both the photoconductive element Rx and the neon lamp L2 are enclosed in an opaque box 1 for keeping them shielded from the incidence of external light rays. The outlet and la of the lead wires for the respective parts housed in said box I are provided with opaque members (not shown) for shielding the entry of external light rays therethrough. The photoconductive element Rx which is disposed in optically opposing relation with the neon lamp L2 will have a resistance value which remains to be decreased up to a level (normally very low) corresponding to the quantity of light from the lamp L2 when lighted up. However, when the lamp is dark, said re sistance value will increase up to the level of dark resistance which is very great.
Now, consideration will be made on the circuits shown in Fig. l in which the changeover network 12 is incorporated. In Fig. 1, let us assume that the reactance of the capacitor C is relatively small. Then, upon the application of an AC voltage between the terminals a and a and upon the closing of the setting switch SW, there will be flowan alternate current i through the circuits a -SW-R2-Ca'. Accordingly, the neon lamp L is lighted up and along with this the resistance value of the photoconductive element R, drops to a very low level. Even when the closed setting switch SW is opened at this stage, the lamp L will continue to be lighted up, since the current which flows through the lamp L is allowed to pass through the circuit a-Rx-RZ-LZ-C-a. Let us assume that the setting switch SW is adapted to break after it has made temporarily. It is necessarythat the lighting up of the neon lamp L in the present invention be such that the state of being lighted up is self-retained by means of the photoconductive element Rx, with the exception of the transitory period of lighting of the same by the making of said switch SW for the period of the initial service before an interruption. For this reason, the setting switch SW desirably is of the type which is operative in such a way that it is manually brought into the on state temporarily and which, upon the removal of the user's fingers therefrom, will instantly return to its off state. It should be noted also that during the initial service period before an interruption, the neon lamp L1 will not flicker. This is because of the fact that, with the capacitor C being selected so that it has a very small reactance, the direction of the AC voltage applied across the capacitor C will be reversed before the voltage Vc reaches the firing voltage necessary for causing the neon lamp L1 to luminesce, resulting in that the direct current 1 which flows into the capacitor C is forced to be discharged. It should be noted that the symbol R2 represents the steady resistance of the neon lamp L2. In case an auxiliary resistor (shown in a dotted line) is connected between the point d at which the capacitor C is connected with the neon lamp L1 and one a of the terminals, said resistor R2 may be removed from the aforesaid opaque box I By doing so, the box I can have a more compact size. In case the auxiliary resistor is added to the position indicated by the dotted line, this auxiliary resistor will control, with the cooperation of the resistor R1, the cycle of flickering of the lamp LI at such time in which the service is resumed following an interruption.
Next, it will be understood that in case of an interruption where no AC voltage is applied between the terminals a and a, both of the neon lamps L1 and L2 are not lighted as a matter of course.
Then, next, at the time of resumption of service following the last interruption in which an AC voltage is applied again between the terminals a and a, it should be noted that the setting switch SW remains to be open, so that the photoconductive element Rx has a very great dark resistance and accordingly the lampLZ remains to be dark. In view of the very great impedances of both the photoconductive element Rx and the lamp L2 however, the terminals b and b are rendered to the state in which they are virtually open relative to each other. Therefore, the direct current I will charge the capacitor Cup to the level of the firing voltage, with the result that the neon lamp L1 will effectflickering with a cycle determined by the timing resistor R1 and the capacitor C in such a manner as discussed above.
According to the present invention, the neon lamp Ll remains to be dark for the initial service period before an interruption and also for the subsequent period of interruption. However, this lamp Ll will continue to flicker for the period of resumption of service following this interruption. The current which actuates the neon lamp, as an indicator lamp of the type described, is very small in magnitude. For example, it may be below 0.5 ma. Thus, there occurs very little consumption of power.
Now, description will be made hereunder on the device suitable for the user to externally view the luminescence of the neon lamp L2 which is lighted up for the initial service period prior to any interruption. Description will be made also on the device for starting the lighting up of the neon lamp L2 by relying on an optical switch and without the use of an electrical switch. Description will be made further on the circuit equipped with a neon lamp L3 which is provided in parallel with the lamp L2 but externally of the box. Their descriptions will be made by referring to Figs. 2 through 4 which each contains like reference numerals that are given those parts which perform in the same way as those parts shown in Fig. 1.
In Fig. 2, reference numeral 2 represents a box having a small indicator aperture 2b formed in one of the walls and also having a lead wire deriving port 2a. Numerals 3 and 4 represent polarizing filters which are disposed in such a way that their optical faces are turned through relative to each other. Because of this arrangement, the light rays emitting from the neon lamp L2 pass through the polarizing plate 3 and exit outwardly of the box. At the same time, the light rays pass through the other polarizing plate 4 and enter into the photoconductive element Rx. However, external light rays, such as the solar rays and the light rays from electric bulbs, are unable to pass through the polarizing plate 4 after they have passed through the polarizing plate 3. Therefore, these light rays are not applied to the photoconductive element Rx. More specifically, the opaque box 2 which contains two polarizing plates 3 and 4 that are both disposed so as to face the indicator aperture 2b will behave in the same way as does the opaque box 1 shown in Fig. l with respect to the external light rays,
with the exception of the fact that the box 2 is arranged so that the light rays from the neon lamp L2 can be afiirmatively recognized visually from outside the box. Accordingly, the behavior which was described in connection with Fig. 1 is accomplished equally as well in this instance also. Thus, the state in which the neon lamp L is dark while the neon lamp L2 is lighted up signifies the period of initial service before an interruption. Whereas, the state in which both of the neon lamps L1 and L2 are dark signifies that the service is suspended. On the other hand, the state in which the neon lamp L1 is dark and the neon lamp L2 is lighted up means that the service has been resumed following the last interruption.
In Fig. 3, reference numeral 5 represents a light-shielding box having a small closable aperture So for introduction of external light rays thereinto. Numeral 6 represents a movable cover disposed in the foreground of said small aperture 5a for free movement to cover and uncover said small aperture. Inside the box 5 is housed a photoconductive element Rx which is disposed at a position facing said small aperture 5a, and also housed in said box 5 is a neon lamp L2 which is disposed at a position at which the lamp can irradiate the photoconductive element Rx. With the box of the foregoing arrangement, the cover 6 which is made of an opaque material may be moved temporarily off the small aperture 5a which is intended for introducing external light rays into the box. Whereupon, external light rays are applied to the photoconductive element Rx through the small aperture 5a, and the resistance value of the element Rx through the will thereby drop accordingly. With this, the neon lamp L2 will be lighted up. This luminescent state of the lamp continues until after the small aperture 5a is subsequently covered again. In other words, the cover 6 for setting the lamp L2 to be retained in its lighted state will play role of an optical switch means in the same way as is done by the electrical setting or starting switch SW shown in Fig. 1. In case the device is used under the circumstance in which external light rays are always present therearound, this arrangement of the cover 6 is capable of giving a desirable means to provide a simplified optical switch structure.
In Fig. 4, there is shown a circuit diagram having a neon lamp L3 which is provided externally of the closed box 1 and which is connected in parallel with the neon lamp L2 shown in Fig. 1. This neon lamp L3 which is provided externally of the closed box 1 and which is connected in parallel with the neon lamp L2 shown in FIG. 1. This neon lamp L3 is adapted to be lighted up only when the neon lamp L2 is lighted up. The types of indication exerted by these lamps L1 and L3 are identical with those given by the lamps L1 and L2 that have been discussed in connection with Fig. 2. The impedance changeover circuit in Fig. 4 contain two neon lamps. In the instant example, the resistors R1 and R2 are those which can serve concurrently as the steady resistors that are used for compensating for the difference in the firing voltage between the neon lamps L2 and L3.
In an actual circuit arranged according to the present invention, the electrical elements shown in Fig. 4 will be as follows in case the input AC voltage applied between the terminals a and a is AC 100 v. and in case the cycle of flickering of the neon lamp L1 is about 2.5 times per second:
The present invention has been described in connection with specific embodiments. It should be understood, however, that various modifications of the invention may be made by those skilled in the art without departing from the scope and the spirit of the invention.
1. A device for indicating interrupted AC service, comprising a series circuit containing a rectifier, a timing resistor and a capacitor and connected between AC service terminals, a first discharge tube connected in parallel with said capacitor, a series circuit containing a photoconductive element and a second discharge tube and being connected in parallel with said first occurring series circuit containing the rectifier and the timing resistor, and a switch means connected in parallel with said photoconductive element, both of said photoconductive element and said second discharge tube arranged to face said photoconductive element being enclosed in a box made of an opaque material to thereby shield external light rays from being applied to said photoconductive element.
2. A device according to claim I, in which said opaque box is equipped with an indicator aperture, there being provided a first polarizing plate at a position at which this plate covers said aperture, there being provided within said box a second polarizing plate spaced from said first polarizing plate and arranged so that its optical face is turned through relative to the optical face of said first polarizing plate, said second discharge tube being arranged between said first and second polarizing plates, said photoconductive element being arranged to face said second discharge tube with said second polarizing plate interposed therebetween, whereby the light ductive element.
5. A device according to claim 1, in WhlCh there IS provided an auxiliary resistor between a point of connection (d) of said capacitor with said first discharge tube, said point of connection being located on the side not connected with said timing resistor, and one (a') of said AC service terminals not connected with said resistor nor with said rectifier.
6. A device for indicating interrupted AC service, comprising a series circuit containing a rectifier, a timing resistor and a capacitor and connected between AC service terminals, a first discharge tube connected in parallel with said capacitor, and a series circuit containing a photoconductive element and a second discharge tube and being connected in parallel with said first occurring series circuit containing the rectifier and the timing resistor, both of said photoconductive element and said second discharge tube being enclosed in an opaque box having an aperture for introducing external light rays thereinto, said aperture being covered by a movable opaque cover member to thereby pennit said photoconductive element to be temporarily subjected to external rays through said aperture.