US 2608614 A
Description (OCR text may contain errors)
Aug. 26, 1952 J. E. WILLIAMS SIGNALING DEVICE Filed oct. 8. 1948 ww m WN ma j y w Patented Aug. 26, l 1952 John E.- Wiuiams, Woodside, N. Y.
Application October 8, 1948, Serial No. `53,498
The present invention pertains to signaling devicesand more particularly to signaling devices adapted to attract the attention of persons who are hard of hearing. A I
An object of the invention isto convert an audible signal intoa signal of a different type which 'can be readily `detected by aA person whose acuity of auditory perception is seriously impaired. Y
A further object of the invention is to provide such a converting device which Will produce both a visual signal and a tactile signal in response tov a signal which should be normally audible to a person whose hearing is unimpaired.
Another object of the invention is to provide means `for conveniently reproducing the signal at one or more locations a short distance removed from the principal signal.
Other and further objects will become apparent upon reading the following specification togetherv with the accompanying drawing forming a part hereof. l f
Referring to the drawing:
\ 'g. 1 is a circuit diagram of anembodiment Tof the invention;A
FigLZ is a circuit diagram ofa remote receiving apparatus for use with the embodiment illustrated in Fig. l. y Fig. '3 is `ai diagrammatic representation of a piezoelectricvibration pickup device for use with Fig.'.4 is a diagrammatic representation of an electromagnetic pickup device for use with Fig. 1 instead of the piezoelectricpickup device of 1Referring to .Fig. 3, a vibration responsive 4pieroelectric Apickup or'transducer device Il is shown arranged .to be placed in direct mechanical contact with av telephone subscriber set I 2 which is indicated diagramm-atically as being of the combined type in 4which the ringer is contained lwithin-the` hand set mounting. `Inthe case of set housing in which the ringer is enclosed.
Piezoelectric vibration pickup II is relatively "insensitive to ordinary sound frequencies and is so constructed-that it responds with maximum sensitivity to low frequency vibrations in the `general range of the 2 0 cycle frequency commonly employed for the operation of telephone ringers.A
Fig. lshows modied form of pickup or trans- `1 Claim. (Cl. 177-335) ducer I I' comprising a magnetizable core 10 disposed in electromagnetically responsive relationship to a coil 'II which consists of a suitable'num@ ber of turns of wire connected intermediate conductors I3 and I4. The core I0 may be so positioned that it is influenced by the strayelectromagnetic ield1 of the ringer of telephone instru'- ment I2 thereby inducing a voltage in coil 1I upon energization of the ringer. The coil 1I is shown shunted by a capacitor 'I3 which maybe selected to produce resonance at the frequency of the alternating current used for operation of the ringer. This will produce increased sensitivity at the desired frequency and reduced sensitivity to stray magnetic elds of other frequencies. Instead of resonating coil 1I atthe frequency of the alternating current resonance at some `multiple of this frequency other than lunity maybe desirable in certain instances. It may also be positioned in the earths field or` in a `stronger permanent magnetic field so that the mechanical vibrations accompanying operation of the ringer will cause the core or coil o1" both to change position relative to the permanent field, thereby inducing a voltage in coil 'II Whichis developed as a result of mechanical vibration independently of the further voltage which may be induced as a result'l of the straymagnetic eld of the ringer.
The output of the piezoelectric vibration pickup Il or electromagnetic pickup II'is applied via conductors I3 and I4 t0 a potentiometer 4I5 which in turn, is shown connected to the grid I6 of a triode designated generallyas lliwhich forms a part of a two-stage amplier. The anode I8 of triode I 'I is connected through a coupling resistor I9 to a suitable source of anode potenti-al designated B+. The output of triode `I'I is taken via coupling capacitor 20 togrid v2| of a further amplier triode 22.
Anode 23 of triode 22 is energized through a coupling resistor 24 from the anode supply source designated B+. The output of triode 22 is applied via coupling capacitor 25 toa rectier 26. The output of rectifier` 26 develops `a negative potential across resistor 21 which is in turn applied through a low pass lter combinationof resistor `28Y and capacitor 29 to grid -30 of a triode 3l. The anode 32 of triode 3| is energiaedfrom anode supply B+ through the operating winding 33 of a relay designated generally as 341;
The normal potential 0n glid 30 of triode 3| is such that the anode current will be suicient to maintain relay 34 in an energized condition. Accordingly, armature 35 of relay 34 will nordropping resistor 4l.
3 mally be attracted and the circuit between armature 35 and contact 35 will be held open.y
The contacts (i5-350i relay 34 are included in a circuit which comprises a plug 31 adapted .to establish connection to a suitable source of commercial electric power and is indicated as being connected at one side within the apparatus to a conductor l2 and at the other side via conductor 39 to a visual signal represented illustratively as a lamp 40 and a tactile signal indicated by way of illustration as a vibrator 4|. The energizing circuit for these two signals may be completed by connecting conductor 12 to conductor 42. The energizing circuit may bethus completed by closure of relay contacts 35-36 or by closing the contacts of a push button 43.
Response characteristics of vibration detector Il of Fig. 3 or detector H of Fig. 4 are such that either of these detectors is relatively unrespony sive to ordinary sounds. It is arranged to be sensitive however to low frequencies such as those produced by the mechanical contact of the telephone ringer clapper with the gongs. Undesired Aresponse to ordinary sounds such as room noise,
increase the negative bias on the grid of triode 3i thereby causing relay 34 to release. Upon releasing, relay 34 closes contacts 3-5-35 establishing a connection from conductor 'l2 to conductor v4.2, thereby energizing both visual signal 4D and tactile signal 4 l.
A time delay effect may be derivedby proper selection of the time constants of resistors 21-28 and capacitor 29 so that by applying an unusually strong signal to grid i6 of amplifier triode Il,
the duration of the release interval of relay 34 maybe prolonged beyond that which is normally incidental to the periodic operation of the ringer contained within the telephone instrument I2. If desired, separate timing means may be similarly employed.
'Where' it is desired to produce supplementary vvisual and tactile signals in response to opera- `tion of the ringer within telephone instrument I2 but. with the supplementary signals in rooms adjacent to or'at a short distance from the room in which principal signals 40 and 4I are situated, a. power line carrier current transmitter unit may be energized simultaneously with the energization of signals and 4l. Such a unit is shown and is of conventional construction being designated generally as 44. Powerline carrier current transmitter unit 44 is shown illustratively as comprising a triode 45 having a quick heating lament 45 which is energized through a voltage Anode 48 of triode 45 is energized from conductor 39 of the power line through a winding 49 of an oscillator coil designated generally as 5t. The oscillator circuit in ,itself forms no part of the present invention and `itis therefore not described in detail. Any vdesired form of oscillator circuit may be used. The `output of the oscillator which comprises triode 45, however, is applied to power line conductors 38. and 39 and it is transmitted over the usual Apowervsupply wiring to other power supplyoutnection to a suitable power supply outlet and which will therefore receive signals applied to conductor 39 of Fig. 1. The receiver comprises a gas filled triode `52 which may be of the cold cathode type and which therefore normally draws no energy from the power supply. A capacitor 53 is shown connected in series with an inductive reactor 55. The circuit constants are so selected that the circuit comprising capacitor 53 f and reactor 55 is resonant at or near the signal frequency produced by power line carrier current transmitter unit 44. Upon receipt of a signal, the potential at cathode 51 of gas lled triode 52 is instantaneously rendered more negative thereby causing ionization of the gas within the triode. Upon ionization, triode 52 becomesconductive-and current from the power line via conductor 58 flows through the winding 59 of relay E0 to the anode 6| of triode 52. V
The sensitivity of the receiver of Fig. 2 may be. adjusted by the control potentiometer 62 which is shown connected in series with a iixed resistor 63 between power line conductors Iv58 and 64. This potentiometer will vary-the effective grid bias on triode `52 and also vary the amount of received signal applied to this grid. Upon ionization of the gas within triode I52, relay 60 is immediately energized and closes its contacts F15-66. Closure of contacts 65-66 of relay 60 completes the circuit from power line conductor IS4 to visual signal 40 and tactile signal 4|', which are similar in all respects to visual signal 4B and tactile signal 4l, respectively, at the originating location illustrated in Fig. 1.
1 It will thus be seen that the ringing signal of the telephone instrument l2 is converted into both a visual signal and a tactile signal each ofrwhich will readily attract the attention of a person who is hard of hearing. This is accom'- plished without any direct electrical connection to the telephone circuits thereby avoiding any possibility of interconnection between the power supply and telephone systems through insulation failure or other faults of a similar character. Such interconnectionscan be extremely hazardous, not so much from the standpoint of the subscriber at whose premises the fault occurs, as from vthe, standpoint of other 'subscribers whose instrumentalities are connected to the same telephone system by insulation,A of relatively low breakdown voltage characteristics. It is extremely desirable, therefore, to provide effective and dependable electrical separation between the telephone and power systems. `While this might be effected by means of a suitable relay, the present invention permits the same result to be obtained and at the same time prevents any complications from the standpoint of responsibility for maintenance and the possibility of causing an inadvertent connection between the telephone and power systems.
The invention further provides two types of signals which will readily attract the attention of a person who is hard of hearing and which signals will operate in response to the mechanical vibration of the ringer within the telephone instrument l2.
Where a power line carrier transmitting device 44, as indicated in Fig. 1, is utilized in conjunction with one or more receiving instruments as shown in Fig. 2, the push button 43 of Fig. l may be used to summon the person who is hard of hearing in the same manner as if a telephone call were being received. Thus the device is suitable for use as a paging or call system.
I have shown what I believe to be the best embodiments of my invention. I do not wish, however, to be conned to the embodiments shown, but what I desire to cover by Letters Patent is set forth in the appended claim.
In a device which is responsive to mechanical vibrations of the character produced by the operation `of a telephone ringer, a transducing means disposed to receive the vibrations and convert them into an electrical current of relatively loW frequency, and amplifier for amplifying the low frequency currents, a rectier for converting the amplified currents into a unidirectional current, a vacuum tube having a control grid, an anode and a cathode, the unidirectional current being applied to the control grid to vary the anode cathode current of the vacuum tube, a relay connected in the anode cathode circuit of the tube and responsive to 6 variation of the magnitude of the current, a signal operative to attract the attention of a deaf person responsive to actuation of the relay, a power line carrier current transmitter energized simultaneously with the signal, a receiver responsive to the carrier current transmitter, and a further signal controlled by the receiver and operative to attract the attention of a deaf person at a location spaced from the location of the first-named signal.
JOHN E. WILLIAMS.
REFERENCES CITED The following references are of record inv the le of this patent: l
UNITED STATES PATENTS Number Name Date 1,686,138 Marvel Oct. 2, 1928 1,690,279 Craft Nov. 6, 1928 2,031,919 Bennett et al. Feb. 25, 1936 2,193,077 Saxman Mar. 12, 1940 2,400,571 Olesen May 21, 1946 2,467,732 Davis Apr. 19, 1949 2,494,451 Olson Jan. 10. 1950 FOREIGN PATENTS Number Country Date Great Britain Sept, 5, 1935