US3798672A

US3798672A - Multiple condition sensing and audio warning system

Info

Publication number: US3798672A
Application number: US00262227A
Authority: US
Inventors: J Gregg
Original assignee: JAB CO Inc
Current assignee: JAB CO Inc
Priority date: 1972-06-13
Filing date: 1972-06-13
Publication date: 1974-03-19
Anticipated expiration: 1991-03-19

Abstract

An audio alarm system for monitoring mining operations, or the like, comprising a multi-track magnetic tape playing apparatus with a playback head selectively movable to any one of a plurality of track positions, an audio system connected to the output of the tape playing apparatus including speakers at selected locations, a plurality of condition sensors each providing a signal representative of a condition being sensed. A control circuit responsive to the condition signals initiates operation of the tape playing apparatus and positions the tape head relative to the proper track on a pre-recorded magnetic tape, whereby the audio message played corresponds to the sensed condition. Automatic shut down of a conveyor or other piece of mining equipment is effected at the same time.

Description

United States Patent 11 1 1111 3, 98,672

Gregg, Jr. Mar. 19, 1974 15 1 MULTIPLE CONDITION SENSING AND 3.388.390 6/1968 Caischi 340/221 x AUDIO WARNING SYSTEM 3.713.090 1/1973 Dickinson 179/1002 MD X 3.310.793 3/1967 Takekitakarabe et al. 340/22] [75] Inventor: Joseph Gregg, Jr., Johnstown, Pa. 1

[73] Assignee: Jab Company, Inc., Ebensburg, Pa. Primary Examiner-Gareth D. Shaw Assistant Examiner-Melvin B. Chapnick [22] Flled' June 1972 Attorney, Agent, or Firm-Clarence A. OBrien & [21] Appl. No.: 262,227 Harvey B Jacobson 52] US. Cl. ..360/1g, 34 Q/ 2 21 57 ABSTRACT [51] Int. Cl. G081) 19/00 [58] Field of Search 179/1002 MD, 100.2 CA, audl" alarm system mmtormg mmmg Opera- 179/10O 1 C, 1001 PS, 1003 B 1004 ST tions, or the like, comprising a multi-track magnetic 1002 MD; 340/221 tape playing apparatus with a playback head selectively movable to any one of a plurality of track posi- [56] References Cited tions, an audio system connected to the output of the UNITED STATES PATENTS tape playing apparatus includ ng speakers at selected locatlons, a plurality of cond1t1on sensors each providgs Vogel at 179/1002 MD ing a signal representative of a condition being sensed. 3: 5: x if/jgggg A control circuit responsive to the condition signals 2,571.973 10/1951 Walker 179 1002 MD x l F Operanon of the playmg apparatus and 2.804.501 8/1957 Hart 179/1002 MD x Posmons the tape head dame to the Proper track 2.991.448 7/1961 Diamond et al 179/1002 MD x a PFC-recorded magnetic tape, whereby the audio 3 309 324 9 19 5 Diamond 81 1 u 179 1002 MD x sage played corresponds to the sensed condition. Au- 3.226.540 12/1965 De Priest 179/1002 MD X tomatic shut down of a conveyor or other piece of 3.581.014 5/1971 Vogel et al. 340/221 X mining equipment is effected at the same time. 3.634,846 H1972 Fogiel 340/221 X 3.375.491 3/1968 Hornung et a1. 179/1002 MD X 4 Claims, 6 Drawing Figures Foreign Patents or Applications 10/1930 C ireat Britain... 340/221 0 m o e 28 Q 0 Q 0 i 42 s B [I Q Q I;

, 34 I {HUD Local Speaker I l and Pager Am lifier m Confro/ Bell .1

CKI. Sfarfer 32 L Remofe Spsakers .J. an Pa er spillage car Fire AmpIl'f/ 'ers Sensor Sensor 1 Sensarn I I i 36 3a 40 illllll PAIENIEDMAR 19 1914 I 3.798.672

sum

1 or 2 SPEAKER SPILLAGE /4 M R 22 ssuson SENSOR 2 SENSOR 0 m 0 m 28 Q U Q 0 25 B U Q Q IL 30 Local Speaker l and PagerAmplifi'er 4mm) ConfIO/ Bel! I CKI'. I

1* S arfer 32 L j Remof'e Speakers r J and Pa er spillage Car I Fire I Amplifiers S ns r Sensor sensorl I I I. x. .1 36 38 40 MULTIPLE CONDITION SENSING AND AUDIO WARNING SYSTEM BACKGROUND OF THE INVENTION The present invention is generally related to alarm systems, and more particularly, to an audio alarm system for mining operations, whereby prerecorded audio messages are automatically played in response to corresponding sensed conditions.

In recent years, various alarm systems have been provided for warning or advising persons of hazardous conditions or malfunctions encountered in mining and manufacturing operations. With the use of modern mining equipment, and a recent increase in the concern over mining safety, it has become most desirable to provide means for monitoring a plurality of conditions in order to properly oversee the mining operations and assure safety of the workers. Such conditions may include conveyor belt tension or slippage, gas levels, high or fire, spillage of mined materials, and loading car availability at conveyor locations. While alarm systems have been proposed in the past for monitoring several conditions at the same time, such conventional systems, for the most part, were either unacceptable for mining operations or were prohibitively complex and expensive to manufacture and install. Therefore, it is an object of the present invention to provide a novel audio alarm system which is of relatively simple overall construction, utilizing many standard, commercially available components, yet which is capable of monitoring a plurality of conditions and automatically playing prerecorded messages corresponding to any one of the conditions which occurs.

SUMMARY OF THE INVENTION In accordance with the present invention a unique audio alarm system is provided including a multi-track magnetic tape playing apparatus with means for positioning a playback head relative to a magnetic tape to provide operative alignment of the playback head with one of the tape tracks in response to sensed condition signals, such that a prerecorded message is played corresponding to the sensed condition. Automatic shutdown ofa conveyor or other piece of mining equipment is effected at the same time.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being bad to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of a typical underground mining operation utilizing the audio alarm system of the present invention.

FIG. 2 is a block diagram of the audio alarm system of the present invention.

FIG. 3 is a perspective view of the playback head associated with the present invention.

FIG. 4a is an elevational view of the playback head associated with the present invention in operative engagement with a first track of a magnetic tape.

FIG. 4b is an elevational view similar to FIG. 4a, but with the playback head positioned in operative engagement with a second track of the magnetic tape.

FIG. 5 is a schematic diagram of the preferred embodiment of the circuitry associated with the present invention.

DETAILED DESCRIPTION OF AN EMBODIMENT Referring now, more particularly, to FIG. 1 of the drawings, a typical underground mining operation adapted to utilize the audio alarm system is illustrated. Typically, such a mining operation would include material handling equipment such as a belt conveyor indicated at 10 which delivers the mined materials, such as coal indicated at 12, to a plurality of material carrying cars 14. The cars are coupled together in a conventional manner and are adapted to ride on rail tracks 16 leading to a tunnel opening. A pair of

car sensors

18 and 20 are located adjacent to the rail tracks and include conventional feeler switches which wipe against the cars as they are advanced, the absence of a car side surface at both sensor locations being effective to provide an appropriate signal to indicate that additional cars are needed. In addition, a spillage sensor 22 is mounted adjacent to the end of belt conveyor 10 to provide an appropriate signal in the event of overloading, or the like. Preferably, the sensor includes a conventional weight-responsive switch, not illustrated, which is actuated by a buildup of the spilled materials.

In the event that either the material carrying cars be come depleted, or spillage occurs during loading, a corresponding pre-recorded message will be played through a plurality of speakers 24 mounted at different locations in the mine. Preferably, these messages will also be heard at other appropriate locations, whereby the sensed condition may be expeditiously corrected. It will be appreciated that additional sensors may be provided in the overall system to provide signals representative of other conditions which might foreseeably occur in the mining operation. Such sensors may include fire or gas detectors, or conveyor tension, slippage, or overload sensors.

With reference to FIG. 2, it will be observed that the audio alarm system of the present invention is generally indicated by the numeral 26 and includes a multi-track magnetic tape playing apparatus 28 adapted to receive input signals from a control circuit 30 to provide playback of appropriate pre-recorded messages through an audio output system including local and remote speakers, as indicated at 32 and 34. The control circuit is operated by signals received from various sensors, such as the spillage sensor 36, car sensor 38, or fire sensor indicated in dash at 40. Tape playing apparatus 28 is provided with a multi-track magnetic tape 42, preferably of the endless type, which is advanced past a playback head 46, by conventional means. If desired, the magnetic tape may be of the cassette" or cartridge type.

It will be appreciated, that the elongated magnetic tape is provided with a plurality of transversely spaced tracks or channels, in a conventional manner, such as the four-track or eight-track tapes which are commercially available and often utilized for musical recordings. For the sake of simplicity, the audio alarm system herein described is provided with a two-track magnetic tape and control circuit arrangement for responding to signals from the spillage and car sensors, respectively. However, it should be noted that it is not intended that the present invention be limited to the use of two channels and, as many channels as desired may be used within the feasible limits of the magnetic tape and associated playback head. For each type of sensor in the system, there is a corresponding pre-recorded message on an appropriate track of the magnetic tape. The control circuit includes means which are effective to select the proper track and pre-recorded message dependent upon the type of condition which is sensed. In addition, the control circuit includes means which are effective to disenable the conveyor by way of its associated belt starter, as indicated at 44. Thus, it will be appreciated that the audio alarm system of the present invention includes means for automatically playing a prerecorded message indicative of a sensed condition and, if desired, effect automatic shutdown of the material handling conveyor or similar equipment.

With reference to FIG. 3, it will be observed that the tape playing apparatus is provided with a conventional playback head 46, which, for the purposes of simplicity, is illustrated with a single pickup track 48 adapted to operatively engage a corresponding track of the magnetic tape as it is advanced by the playback apparatus drive mechanism. An electrically operated solenoid 50 is provided with a movable core 52 operatively connected to a mounting base 54 associated with the pickup head. When the solenoid is energized, it is effective to impart movement to the playback head in a downward direction transversely of the magnetic tape. Such mechanisms, or variations thereof, are provided with several commercially available tape playing devices, one such device being manufactured under the trade name of Kraco." Normally, the Kraco apparatus utilizes the playback head positioning solenoid to effect switching from one group of tracks to another either through pre-recorded signals or manual switches, whereby it is possible for a user to switch to the desired magnetic track for listening to the pre-recorded material thereon. However, with the audio alarm system of the present invention, the solenoid is operated by the control circuit indicated at 30 in the block diagram of FIG. 2.

FIG. 4a illustrates the playback head and the associated solenoid in an upper position such that the pickup track 48 of the playback head is in wiping engagement with track No. l of magnetic tape 42. Preferably, the solenoid is provided with a coil compression spring 56, or the like, which is effective to maintain the playback head in the position illustrated in FIG. 4a, unless solenoid 50 is energized by appropriate means, such as the control circuit. Upon energization, the solenoid is effective to move the playback head downward to a position shown in FIG. 46 where its pickup track 48 is in wiping engagement with track No. 2 of the magnetic tape. It will be appreciated that several positions may be provided for by utilizing a multi-position solenoid, stepping switch, or similar appropriate means, whereby a corresponding number of sensed conditions and pre-recorded messages may be automatically handled by the alarm system.

Referring now, more particularly, to FIG. 5 of the drawings, a schematic diagram of the circuitry associated with the present invention is generally indicated by the numeral 58 and is adapted to handle two types of condition sensors and corresponding pre-recorded messages. However, as mentioned above, this circuit may be appropriately modified to accommodate additional condition sensors and corresponding prerecorded messages. In addition, electrical interlocks may be provided to maintain the system on until the sensed condition has been attended to. Preferably, the car availability sensor is comprised of a pair of serially connected switches Sw.l and Sw. 2 which mechanically sense the presence of the side of a car as the cars are advanced, as illustrated in FIG. 1. The switches are of the normally closed type, such that the absence of a car is effective to close the switch contacts. Two switches are provided as illustrated in FIG. I to prevent false sensing due to the gaps normally present between adja cent cars. The material spillage sensor includes a weight responsive switch Sw. 3 connected in parallel with switches Sw. 1 and Sw. 2.

The audio alarm system is provided with a control circuit including an appropriate voltage source, such as a pair of serially connected 12 V. batteries. A control relay CR is connected to the voltage source by way of a normally closed time delay contact TDIA and a test switch. A pair of time delay relays TDI and TDZ are serially connected to the sensor switches and test switch and are in parallel with each other. It will be appreciated that closure of either the test switch, the car availability switches, or the spillage switch will be effective to energize control relay CR, to effect operation of the associated contacts.

Preferably, the tape playing apparatus is provided with a 12 V. supply which is connected to the tape ad vance mechanism motor M by way of a normally opened contact CR1 and a fuse 60. The playing apparatus is also provided with a on-off switch 62 and an on indicating lamp 64. A solenoid coil 66 associated with the track control solenoid 50 is connected to the voltage source thorugh a normally closed contact TD24 and normally opened switch Sw. 4. It should be noted that switch Sw. 4 serially connected to solenoid 66 is arranged for simultaneous operation with spillage sensor switch Sw. 3. This is achieved by either ganging Sw. 3 and Sw. 4 together or electrically interlocking such by way of a relay or the like. Output signals from the pre-recorded messages are provided by way of an audio transformer 68, the secondary of which is con nected to the local and remote speaker and

pager amplifiers

32 and 34, respectively. A cut-out switch 70 may be provided for disconnecting the remote pagers 34 from the system during test procedures. The

pagers

32 and 34 are powered by the batteries associated with the control circuit independently of the tape player power supply as shown in FIG. 5.

In addition to the tape playing apparatus, the control circuit is connected to a relay 72 associated with the conveyor belt starter to effect shutdown in response to either of the sensed conditions. This is achieved through normally opened contact CR2 associated with control relay CR. The coil of relay 72 is coupled to the secondary of audio transformer 68 by way of normally opened contact CR3 and a choke coil 74.

Operation of the audio alarm system utilizing two channels, as illustrated in FIG. 5, may be described as follows. Assuming that a spillage condition does not exist and that the test switch is opened, the absence of the required number of material carrying cars at the conveyor site is effective to close both SW. 1 and Sw. 2. This operation initiates an off delay time interval associated with time delay relay TDI and at the same time energizes control relay CR. Energization of the control relay is effective to close normally opened contacts CR1, whereby motor M is energized to advance the magnetic tape. As the tape is advanced, the appropriate pre-recorded message is played through

pagers

32 and 34 by way of audio transformer 68. Upon completion of the pre-recorded message, or shortly thereafter, time delay relay TDl is effective to open the associated contact TDlA, whereby relay CR is deenergized and the tape playing apparatus is disenabled by opening of contact CR1.

It will be appreciated, that in addition to the initial enablement of the tape playing apparatus, control relay CR is also effective to energize relay 72 by way of contacts CR2 and CR3. This operation, in turn, is effective to open the control contacts of the conveyor belt starter to bring about automatic shutdown of the material handling conveyor.

In the event that a spillage is sensed, switch Sw. 3 is closed, whereby control relay CR is energized to actuate the tape playing apparatus as explained above. In addition, closure of Sw. 3 brings about simultaneous closure of Sw. 4, whereby solenoid coil 66 is energized to move the playback head to the proper position to play the pre-recorded message corresponding to the spillage condition. Upon initial closing, Sw. 3 initiates an off time delay associated with a time delay relay TD2. Upon completion of the off" time delay interval, the normally closed contacts TDZA serially connected to solenoid 66 are opened to return the solenoid and playback head to its original position.

From the foregoing description, it will be appreciated that the audio alarm system of the present invention provides a relatively simple, yet versatile means of automatically monitoring several conditions of a mining operation or the like. Since the system utilizes several standard, commercially available items it is relatively inexpensive to manufacture and install. Many multitrack tape playing devices may be utilized by making only minor modifications, such as those indicated above. Further modifications may be appropriately made to accommodate more channels than those illustrated in the drawings.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.

What is claimed as new is as follows:

1. In combination with a tape player having a single playback head selectively displaced between a plurality of positions operatively aligned with a plurality of tape tracks on which different messages are recorded, a warning system comprising a plurality of sensing devices for respectively monitoring different conditions; relay means energized by said sensing devices independently of the tape player for rendering the tape player operative; means connected to said sensing devices for selecting one of the positions to which the playback head is displaced when the tape player is rendered operative, corresponding to one of the recorded messages associated with the condition monitored by one of the sensing devices; time delay means energized simultaneously with the relay means for deenergizing the same and disabling the tape player after elapse of timed intervals during which the player is operative; and audio output means coupled to and energized independently of the tape player during said timed intervals for reproducing the recorded messages.

2. The combination of claim 1 including shutdown control means connected to the relay means for preventing operation of external equipment during said timed intervals.

3. The combination of claim 2 including a source of electrical energy connected to the relay means, the time delay means and the audio output means for energizing the same independently of the tape player.

4. The combination of claim 1 including a source of electrical energy connected to the relay means, the time delay means and the audio output means for energizing the same independently of the tape player.