Emergency vehicle siren switching apparatus
United States Patent 3868684
An emergency vehicle audible warning system having a control circuit with a means for switching said control circuit to activate a tone generator for creating a yelp tone or a wail tone. A siren amplifier interfaces a siren speaker and the yelp and wail tone generators. A series of switches are also provided in operative connection with the horn ring of an automobile or a foot switch, so that the yelp or wail tone can be effectuated thereby upon the demand of the driver of the emergency vehicle.
US Patent References:
Horn system
Hueber et al. - May 1936 - 2039717
Oscillator for the biological treatment of living tissue
Caesar - November 1937 - 2099511
Oscillation generator
Elliott - March 1958 - 2826691
Electrical audio range sweep oscillator
Bonner et al. - September 1959 - 2903648
ELECTRONIC SIREN CIRCUIT
Smith - July 1973 - 3747092
Horn system
Hueber et al. - May 1936 - 2039717
Oscillator for the biological treatment of living tissue
Caesar - November 1937 - 2099511
Oscillation generator
Elliott - March 1958 - 2826691
Electrical audio range sweep oscillator
Bonner et al. - September 1959 - 2903648
ELECTRONIC SIREN CIRCUIT
Smith - July 1973 - 3747092
Application Number:
05/216002
Publication Date:
02/25/1975
Filing Date:
01/07/1972
View Patent Images:
Export Citation:
Primary Class:
International Classes:
B60Q5/00; G08B3/00
Field of Search:
340/405,406,75,88,384E 179/1SA
Primary Examiner:
Caldwell, John W.
Assistant Examiner:
Curtis, Marshall M.
Claims:
I claim
1. The combination of a vehicle and an audible warning system which comprises:
2. The combination as claimed in claim 1 wherein said switch means comprises the switch connected to the horn ring of the vehicle.
3. An improved audible warning system in combination with an emergency vehicle comprising:
4. The combination as claimed in claim 3 wherein said switch means in part comprises:
5. The combination as claimed in claim 4 wherein:
6. The combination as claimed in claim 4 wherein:
1. The combination of a vehicle and an audible warning system which comprises:
2. The combination as claimed in claim 1 wherein said switch means comprises the switch connected to the horn ring of the vehicle.
3. An improved audible warning system in combination with an emergency vehicle comprising:
4. The combination as claimed in claim 3 wherein said switch means in part comprises:
5. The combination as claimed in claim 4 wherein:
6. The combination as claimed in claim 4 wherein:
Description:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The field of this invention lies within the audible warning tone generation art as it relates to emergency vehicles.
2. The Prior Art
The prior art relating to the generation of audible warning tones for emergency vehicles such as police, fire, and ambulance type vehicles, initially incorporated the use of a siren. The siren was generally activated by a switch and effectively created a sound which warned surrounding vehicles that an emergency vehicle was moving rapidly nearby.
As emergency vehicles were later developed, certain apparatus was incorporated in emergency vehicles such as radios, floodlights, and many other devices such as public address systems. As a consequence, various switching functions had to be developed to provide for the various accessories that were included with emergency vehicles. The state of the art was such that many of the devices had to be turned on and off in a separate manner until the patent to E. D. Nunn, Jr., U.S. Pat. No. 3,262,096, the applicant herein. In that patent a control system for emergency vehicles was disclosed which provided for the proper switching of the horn, siren, radio circuit and numerous other optional features in a single control unit. This effectively enabled the operator of an emergency vehicle to operate all the accessory equipment of an emergency vehicle through a single control source.
In the development of the single control unit, a switch was utilized for certain audible warning tones. One of the warning tones was a wail. The wail is effectuated by a slow rise and fall between the high and low tone ranges. The wail tone is substantially effective in certain areas. However, a yelp tone which provides a substantially distinguishable high to low tone with a much faster rise and fall of the tone is considered to be more effective in certain instances. The yelp tone has provided emergency vehicles with a superior capability of warning approaching automobiles in many cases that an emergency vehicle is about to pass. The wail tone often does not evoke as much human audible response at intersections and as a consequence is not as effective as the yelp.
In order to effectively provide the yelp tone it has been necessary to activate the yelp tone by means of manually turning a switch, such as that on the control unit. This switch is usually placed at a distal and impractical location from a driver. This effectively takes an emergency vehicle driver's hand off the wheel of the vehicle creating a dangerous situation. As a consequence, emergency vehicles until this invention have not had an effective audible warning system incorporating a yelp as opposed to a wail upon ready demand.
This invention enables one to incorporate a yelp tone over or between wail tones upon demand. The demand function is effectuated by use of the horn ring or any other accessible switch means which can be actively and easily switched on by the operator. For example, a foot switch can be utilized to generate the yelp tone over the wail tone. In operation the system functions to create a yelp tone without deactivating the entire circuit by a unique switch function in the controlling unit and tone generating circuits.
SUMMARY OF THE INVENTION
In summation, this invention incorporates the new and novel combination of a horn ring, footswitch or other suitable accessible switch means within the control and audible tone generating circuits of an emergency vehicle to provide a yelp tone over a wail tone upon demand.
Specifically, the invention utilizes a yelp and wail tone generator in combination with a switching relay such as a reed switch to introduce or eliminate a capacitor so that generation of a wail or yelp tone is provided. The switching relay is controlled by means of the horn ring or foot switch activating the switching relay so that the respective wail or yelp tone generators in combination with the amplifier and siren speaker will create the yelp tone over the wail tone upon demand.
In other words, the wail and the yelp tones are respectively created by increased or decreased capacitance in the tone generator oscillator circuits. The tone switching relay takes the capacitance out of the circuit so that the wail which relies upon the increased capacitance cannot be generated by the tone generator, and in lieu thereof a yelp is created. The yelp tone created on demand over a wail tone is extremely valuable for warning oncoming vehicles at intersections and in other dangerous areas.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be more clearly understood by reference to the description, taken in conjunction with the accompanying drawing wherein:
FIG. 1 shows a fragmented perspective view of the interior of an emergency vehicle utilizing the system of this invention;
FIG. 2 is a perspective view of the control system shown in FIG. 1 in greater detail taken from the left side thereof; and,
FIG. 3 is a block and line diagram showing the functioning elements of the system in cooperative relationship.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Apparatus for Practicing the Invention
FIGS. 1 and 2 show a control console 10. The control console 10 is mounted on the dashboard 12 of an emergency vehicle having a steering wheel 14 and a horn ring 16. The vehicle can also be equipped with a foot switch 18 for purposes of operating different components of the invention. The emergency vehicle interior shown in FIG. 1 is otherwise of a standard type similar to that of any emergency vehicle such as an ambulance, fire engine, or police car.
The control console unit 10 has a mounting bracket 20 upon which the device can be mounted with an overbracket 22 for purposes of holding the control console more securely in place. A microphone 24 is shown having a lead 26 into the control console for purposes of providing a public address capability for the emergency vehicle. The microphone 24 has the normal state of the art push button 28 and microphone grid 30.
The console 10 has a case 32 in which the components are mounted and a face place 34 for purposes of identifying the different functions which the console controls. As can be seen, the console 10 is mounted to the bracket 20 by means of a U bracket 36, with rivets 38. However, any other suitable attachment means can be utilized. The face place 34 is secured to the console unit 32 by means of Phillips head screws 40 or any other suitable means 40.
The control console has a master switch 42 which in part serves the function of an audible warning control switch. The switch makes contact by swinging across a wiper plate 82 interiorly of the console. The master switch 42 serves to control a series of functions for the emergency vehicle as indicated by the scribe lines positioned at points 45, 47, 49 and 51. The switch indicates and operates the respective functions of an emergency vehicle such as its flood lights, siren, warning light or any other particular operative features peculiar to an emergency vehicle. The console 10, but not necessarily through the master switch 42 can coordinate the lights, flashing brake lights, locks, headlights, or can be utilized with the vehicle's horn ring to make audible sounds as will be described.
Alongside the edge regions of the console 10 and face plate 34 are a series of indicator lights 54, 56 and 58. The indicator lights indicate at a glance what equipment is operating and what is being controlled by the master switch 42 and the other switches of the console. The indicator lights can be color coded so that the entire device effectively can be monitored by a visual glance to show which respective accessories of an emergency vehicle are operating.
A selector switch 60 is provided to serve in part the function of a tone control switch. The switch 60 can effectively select the audible warning accessories of an emergency vehicle to determine which particular sounds will be made. For instance, the selector switch 60 has different positions generally shown by the dots 62 to turn on the siren for a respective wail tone, yelp tone, high-low tone or manual operation of the siren. The switch 60 can also turn on the radio as well as provide other functions. Thus, the switch 60 controls the operation of the emergency vehicle equipment in a more discrete manner than the master switch 42 which broadly selects the accessories to be operated.
A second rotary switch 66 is provided having a series of dots or selection points 68 which provide positions for operating a radio, the microphone 24, or other similar accessories.
A number of rocker switches 70 can be provided on the face plate 34 to cause the different accessories of an emrgency vehicle to function. For instance, the switches 70 can be utilized to operate an electric trunk lid, floodlights, or interior lights. The rocker switches 70 can also be utilized to provide a shotgun rack release or brake light cutoffs as well as many other options which are useful for an emergency vehicle.
Looking more specifically at FIG. 3 which shows the line and block diagram of this invention, the two previously discussed switches are shown. Specifically, the selector switch 60 and master switch 42 are shown. For purposes of identification means, the master switch 42 and selector switch 60 have been reduced to a limited function of an audible warning control switch and a tone control switch.
When the audible warning control switch 42 is turned to position 3 thereof, it serves to connect the audible tone generator which will be described. Position 2 of the audible warning control switch leads to the emergency vehicle's horn 80. Position 1 connects the lighting system of the vehicle or for that matter could be used to connect any other suitable accessory of the emergency vehicle.
The audible warning control switch 42 has a wiper plate 82 with a junction contact point 84. The contact point 84 leads to a junction 86 by means of connection 88. Junction point 86 is connected to the horn ring 16 and the foot switch 18 through the power supply or battery 94 of the emergency vehicle. The horn ring 16 is effectively a contact switch 96 which is operated by the horn ring when it is depressed. The foot switch 18 is also a contact switch 92. Both switches place the operative features of this invention in an on or off condition depending upon whether they have been respectively actuated.
The audible warning control switch 42 is connected through wiper plate 82 to a lead 100 which in turn is connected to the tone control switch 60. The tone control switch 60 is provided with a wiper plate 102 and has the respectively designated contacts, namely,man (manual), auto (automatic), yelp and hi-lo (high-low). A contact 110 on the wiper plate 102 connects it to lead 100. As can be seen, the tone control switch 60 has been positioned at contact 106 which is the position for operating the auto (automatic) portion of the siren and leads to line 108. Thus, the tone control switch 60 is connected respectively to the horn ring 16 and foot switch 18.
Line 108 is connected to a tone switching relay 114 which can be in the form of a reed switch or any other suitable relay. In the instant embodiment it is preferred to utilize a reed switch because of the size and configuration of the circuit board within the control console 32. The relay can comprise a coil 116 having a core 118. The coil 116 is connected through to ground with respect to the appropriate polarity of the circuit by a circuit matching switch 120 having respective positive or negative connection points 122 and 124. The switch 120 serves to match the horn ring or the foot switch to the automobile circuit, and other portions of the console 10.
The tone switching relay 114 creates a circuit through its junction point 150 by means of connecting the remainder of the circuit to either connection points 126 or 128.
Within the console 10 and mounted on a circuit panel or board 200 is a tone generator preamplifier to provide a wail tone 130. A second tone generator preamplifier provides a yelp tone 132. The wail and yelp tone generators respectively 130 and 132 are incorporated with other circuitry which has been disclosed in such publications as the Unitrol Catalogs of Dunbar Nunn Corporation of 1108 Raymond Way, Anaheim, Calif. as well as the previously cited patent to Ewing D. Nunn, Jr.
The wail tone generator and the yelp tone generator preamplifiers 130 and 132 respectively provide signals to create either a rise or fall in tone at a moderate frequency or a rise from low tones to high tones at a substantially greater frequency.
The tone switching relay 114 is connected at the relay junction point 150 to line 152 which leads to a siren power amplifier 154. The siren power amplifier 154 is powered through connection points 156 and 158. The siren power amplifier increases the overall power of the signal to allow a siren speaker 160 to send forth either the wail or the yelp tone in accordance with the position of the tone switching relay 114 as dictated by the horn ring 16 or foot switch 18.
Operation of the System
As the operator of an emergency vehicle drives, it is common to turn on the siren on an automatic basis to warn oncoming vehicles of the possibility of colliding with the fast moving emergency vehicle. This is accomplished by placing the audible warning control switch 42 into position 3. The operator also places the tone control switch 60 in a position whereby it is in the auto position. The audible warning control switch 42 or master switch can now activate the entire system of this invention.
In this particular mode, the wail tone generator preamplifier 130 is connected through the tone switching relay 114 by means of contact 128. The tone which is generated through the siren speaker 160 in this mode is that of a wail. As previously discussed, moderate frequency from low tone to a high tone in an oscillatory manner characterizes the wail.
Assuming that the operator of the emergency vehicle is approaching an intersection or other particularly dangerous location, the operator will want to attract attention by providing a yelp tone which is a rapidly pulsating low to high tone. In order to effectuate the yelp tone, the operator presses either the horn ring 16 or the foot switch 18 thereby closing contacts 96 and 92 respectively. At this moment in time current passes for purposes of activating the tone switching relay 114.
When the tone switching relay 114 is activated the core 118 pulls the arm 134 to contact 126 to create a yelp tone. In the preferred embodiment, the tone switching relay 114 eliminates a capacitor which is the circuit enclosed within dotted lines or mounted on the circuit board 200 of the console 10. Thus, the yelp tone generator preamplifier 132 can be created by displacement of a capacitor within the entire siren tone circuit. This effectively causes a rapid rise and fall or yelp because the oscillator of the tone generator circuit cannot create the required duration of energy storage through its capacitance as required for a wail tone.
It should be understood that other configurations and modes embodied in the teaching of this invention can be utilized. For instance, other means of placing the capacitor of the wail tone generator in an on-line or off-line position for the effective yelp tone can be utilized. Furthermore, completely separate circuits can be utilized to create the tones with respect to each other. Also, different switching functions can replace the audible warning control switch 42, tone control switch, horn ring, and the foot switch. Thus, the foregoing described invention is only to be read and construed in light of the following claims.
1. Field of the Invention
The field of this invention lies within the audible warning tone generation art as it relates to emergency vehicles.
2. The Prior Art
The prior art relating to the generation of audible warning tones for emergency vehicles such as police, fire, and ambulance type vehicles, initially incorporated the use of a siren. The siren was generally activated by a switch and effectively created a sound which warned surrounding vehicles that an emergency vehicle was moving rapidly nearby.
As emergency vehicles were later developed, certain apparatus was incorporated in emergency vehicles such as radios, floodlights, and many other devices such as public address systems. As a consequence, various switching functions had to be developed to provide for the various accessories that were included with emergency vehicles. The state of the art was such that many of the devices had to be turned on and off in a separate manner until the patent to E. D. Nunn, Jr., U.S. Pat. No. 3,262,096, the applicant herein. In that patent a control system for emergency vehicles was disclosed which provided for the proper switching of the horn, siren, radio circuit and numerous other optional features in a single control unit. This effectively enabled the operator of an emergency vehicle to operate all the accessory equipment of an emergency vehicle through a single control source.
In the development of the single control unit, a switch was utilized for certain audible warning tones. One of the warning tones was a wail. The wail is effectuated by a slow rise and fall between the high and low tone ranges. The wail tone is substantially effective in certain areas. However, a yelp tone which provides a substantially distinguishable high to low tone with a much faster rise and fall of the tone is considered to be more effective in certain instances. The yelp tone has provided emergency vehicles with a superior capability of warning approaching automobiles in many cases that an emergency vehicle is about to pass. The wail tone often does not evoke as much human audible response at intersections and as a consequence is not as effective as the yelp.
In order to effectively provide the yelp tone it has been necessary to activate the yelp tone by means of manually turning a switch, such as that on the control unit. This switch is usually placed at a distal and impractical location from a driver. This effectively takes an emergency vehicle driver's hand off the wheel of the vehicle creating a dangerous situation. As a consequence, emergency vehicles until this invention have not had an effective audible warning system incorporating a yelp as opposed to a wail upon ready demand.
This invention enables one to incorporate a yelp tone over or between wail tones upon demand. The demand function is effectuated by use of the horn ring or any other accessible switch means which can be actively and easily switched on by the operator. For example, a foot switch can be utilized to generate the yelp tone over the wail tone. In operation the system functions to create a yelp tone without deactivating the entire circuit by a unique switch function in the controlling unit and tone generating circuits.
SUMMARY OF THE INVENTION
In summation, this invention incorporates the new and novel combination of a horn ring, footswitch or other suitable accessible switch means within the control and audible tone generating circuits of an emergency vehicle to provide a yelp tone over a wail tone upon demand.
Specifically, the invention utilizes a yelp and wail tone generator in combination with a switching relay such as a reed switch to introduce or eliminate a capacitor so that generation of a wail or yelp tone is provided. The switching relay is controlled by means of the horn ring or foot switch activating the switching relay so that the respective wail or yelp tone generators in combination with the amplifier and siren speaker will create the yelp tone over the wail tone upon demand.
In other words, the wail and the yelp tones are respectively created by increased or decreased capacitance in the tone generator oscillator circuits. The tone switching relay takes the capacitance out of the circuit so that the wail which relies upon the increased capacitance cannot be generated by the tone generator, and in lieu thereof a yelp is created. The yelp tone created on demand over a wail tone is extremely valuable for warning oncoming vehicles at intersections and in other dangerous areas.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be more clearly understood by reference to the description, taken in conjunction with the accompanying drawing wherein:
FIG. 1 shows a fragmented perspective view of the interior of an emergency vehicle utilizing the system of this invention;
FIG. 2 is a perspective view of the control system shown in FIG. 1 in greater detail taken from the left side thereof; and,
FIG. 3 is a block and line diagram showing the functioning elements of the system in cooperative relationship.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Apparatus for Practicing the Invention
FIGS. 1 and 2 show a control console 10. The control console 10 is mounted on the dashboard 12 of an emergency vehicle having a steering wheel 14 and a horn ring 16. The vehicle can also be equipped with a foot switch 18 for purposes of operating different components of the invention. The emergency vehicle interior shown in FIG. 1 is otherwise of a standard type similar to that of any emergency vehicle such as an ambulance, fire engine, or police car.
The control console unit 10 has a mounting bracket 20 upon which the device can be mounted with an overbracket 22 for purposes of holding the control console more securely in place. A microphone 24 is shown having a lead 26 into the control console for purposes of providing a public address capability for the emergency vehicle. The microphone 24 has the normal state of the art push button 28 and microphone grid 30.
The console 10 has a case 32 in which the components are mounted and a face place 34 for purposes of identifying the different functions which the console controls. As can be seen, the console 10 is mounted to the bracket 20 by means of a U bracket 36, with rivets 38. However, any other suitable attachment means can be utilized. The face place 34 is secured to the console unit 32 by means of Phillips head screws 40 or any other suitable means 40.
The control console has a master switch 42 which in part serves the function of an audible warning control switch. The switch makes contact by swinging across a wiper plate 82 interiorly of the console. The master switch 42 serves to control a series of functions for the emergency vehicle as indicated by the scribe lines positioned at points 45, 47, 49 and 51. The switch indicates and operates the respective functions of an emergency vehicle such as its flood lights, siren, warning light or any other particular operative features peculiar to an emergency vehicle. The console 10, but not necessarily through the master switch 42 can coordinate the lights, flashing brake lights, locks, headlights, or can be utilized with the vehicle's horn ring to make audible sounds as will be described.
Alongside the edge regions of the console 10 and face plate 34 are a series of indicator lights 54, 56 and 58. The indicator lights indicate at a glance what equipment is operating and what is being controlled by the master switch 42 and the other switches of the console. The indicator lights can be color coded so that the entire device effectively can be monitored by a visual glance to show which respective accessories of an emergency vehicle are operating.
A selector switch 60 is provided to serve in part the function of a tone control switch. The switch 60 can effectively select the audible warning accessories of an emergency vehicle to determine which particular sounds will be made. For instance, the selector switch 60 has different positions generally shown by the dots 62 to turn on the siren for a respective wail tone, yelp tone, high-low tone or manual operation of the siren. The switch 60 can also turn on the radio as well as provide other functions. Thus, the switch 60 controls the operation of the emergency vehicle equipment in a more discrete manner than the master switch 42 which broadly selects the accessories to be operated.
A second rotary switch 66 is provided having a series of dots or selection points 68 which provide positions for operating a radio, the microphone 24, or other similar accessories.
A number of rocker switches 70 can be provided on the face plate 34 to cause the different accessories of an emrgency vehicle to function. For instance, the switches 70 can be utilized to operate an electric trunk lid, floodlights, or interior lights. The rocker switches 70 can also be utilized to provide a shotgun rack release or brake light cutoffs as well as many other options which are useful for an emergency vehicle.
Looking more specifically at FIG. 3 which shows the line and block diagram of this invention, the two previously discussed switches are shown. Specifically, the selector switch 60 and master switch 42 are shown. For purposes of identification means, the master switch 42 and selector switch 60 have been reduced to a limited function of an audible warning control switch and a tone control switch.
When the audible warning control switch 42 is turned to position 3 thereof, it serves to connect the audible tone generator which will be described. Position 2 of the audible warning control switch leads to the emergency vehicle's horn 80. Position 1 connects the lighting system of the vehicle or for that matter could be used to connect any other suitable accessory of the emergency vehicle.
The audible warning control switch 42 has a wiper plate 82 with a junction contact point 84. The contact point 84 leads to a junction 86 by means of connection 88. Junction point 86 is connected to the horn ring 16 and the foot switch 18 through the power supply or battery 94 of the emergency vehicle. The horn ring 16 is effectively a contact switch 96 which is operated by the horn ring when it is depressed. The foot switch 18 is also a contact switch 92. Both switches place the operative features of this invention in an on or off condition depending upon whether they have been respectively actuated.
The audible warning control switch 42 is connected through wiper plate 82 to a lead 100 which in turn is connected to the tone control switch 60. The tone control switch 60 is provided with a wiper plate 102 and has the respectively designated contacts, namely,man (manual), auto (automatic), yelp and hi-lo (high-low). A contact 110 on the wiper plate 102 connects it to lead 100. As can be seen, the tone control switch 60 has been positioned at contact 106 which is the position for operating the auto (automatic) portion of the siren and leads to line 108. Thus, the tone control switch 60 is connected respectively to the horn ring 16 and foot switch 18.
Line 108 is connected to a tone switching relay 114 which can be in the form of a reed switch or any other suitable relay. In the instant embodiment it is preferred to utilize a reed switch because of the size and configuration of the circuit board within the control console 32. The relay can comprise a coil 116 having a core 118. The coil 116 is connected through to ground with respect to the appropriate polarity of the circuit by a circuit matching switch 120 having respective positive or negative connection points 122 and 124. The switch 120 serves to match the horn ring or the foot switch to the automobile circuit, and other portions of the console 10.
The tone switching relay 114 creates a circuit through its junction point 150 by means of connecting the remainder of the circuit to either connection points 126 or 128.
Within the console 10 and mounted on a circuit panel or board 200 is a tone generator preamplifier to provide a wail tone 130. A second tone generator preamplifier provides a yelp tone 132. The wail and yelp tone generators respectively 130 and 132 are incorporated with other circuitry which has been disclosed in such publications as the Unitrol Catalogs of Dunbar Nunn Corporation of 1108 Raymond Way, Anaheim, Calif. as well as the previously cited patent to Ewing D. Nunn, Jr.
The wail tone generator and the yelp tone generator preamplifiers 130 and 132 respectively provide signals to create either a rise or fall in tone at a moderate frequency or a rise from low tones to high tones at a substantially greater frequency.
The tone switching relay 114 is connected at the relay junction point 150 to line 152 which leads to a siren power amplifier 154. The siren power amplifier 154 is powered through connection points 156 and 158. The siren power amplifier increases the overall power of the signal to allow a siren speaker 160 to send forth either the wail or the yelp tone in accordance with the position of the tone switching relay 114 as dictated by the horn ring 16 or foot switch 18.
Operation of the System
As the operator of an emergency vehicle drives, it is common to turn on the siren on an automatic basis to warn oncoming vehicles of the possibility of colliding with the fast moving emergency vehicle. This is accomplished by placing the audible warning control switch 42 into position 3. The operator also places the tone control switch 60 in a position whereby it is in the auto position. The audible warning control switch 42 or master switch can now activate the entire system of this invention.
In this particular mode, the wail tone generator preamplifier 130 is connected through the tone switching relay 114 by means of contact 128. The tone which is generated through the siren speaker 160 in this mode is that of a wail. As previously discussed, moderate frequency from low tone to a high tone in an oscillatory manner characterizes the wail.
Assuming that the operator of the emergency vehicle is approaching an intersection or other particularly dangerous location, the operator will want to attract attention by providing a yelp tone which is a rapidly pulsating low to high tone. In order to effectuate the yelp tone, the operator presses either the horn ring 16 or the foot switch 18 thereby closing contacts 96 and 92 respectively. At this moment in time current passes for purposes of activating the tone switching relay 114.
When the tone switching relay 114 is activated the core 118 pulls the arm 134 to contact 126 to create a yelp tone. In the preferred embodiment, the tone switching relay 114 eliminates a capacitor which is the circuit enclosed within dotted lines or mounted on the circuit board 200 of the console 10. Thus, the yelp tone generator preamplifier 132 can be created by displacement of a capacitor within the entire siren tone circuit. This effectively causes a rapid rise and fall or yelp because the oscillator of the tone generator circuit cannot create the required duration of energy storage through its capacitance as required for a wail tone.
It should be understood that other configurations and modes embodied in the teaching of this invention can be utilized. For instance, other means of placing the capacitor of the wail tone generator in an on-line or off-line position for the effective yelp tone can be utilized. Furthermore, completely separate circuits can be utilized to create the tones with respect to each other. Also, different switching functions can replace the audible warning control switch 42, tone control switch, horn ring, and the foot switch. Thus, the foregoing described invention is only to be read and construed in light of the following claims.