Abstract:
A hearing protection unit is preferably coupled with a conventional hat, such as a baseball cap, and preferred routing channels extend proximal to an ear of a wearer of the hat. The hearing protection unit amplifies all sounds and delivers a signal to a speaker, which generates sound to be aurally communicated to a wearer&#39;s ears. Upon sensing a predetermined threshold input signal, the speaker signal is modified, thereby allowing controlled suppression of damaging noises.

Description:
RELATED APPLICATION  
       [0001]     This application is a continuation-in-part of U.S. application Ser. No. 10/816,458, filed Apr. 1, 2004. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     This invention relates generally to hearing protection and more particularly to hearing protection suited for loud peak noise environments such as firearms ranges and construction sites.  
         [0003]     To safeguard against permanent hearing loss, hearing protection is essential while firing a firearm or experiencing any loud sound such as from a firing range or operating equipment. Hearing experts normally recommend that hearing protection be worn whenever sound levels regularly exceed 85 decibels (dB) for extended periods. Noise levels from discharging a firearm can range from 120-170 dB. The noise emission from just one gun blast can cause permanent hearing damage. Hunters and shooters generally know they should wear hearing protection but sometimes don&#39;t because of the desire to hear conversation, sounds of the woods and birds flushing. Many shooters do not wear hearing protection because they just don&#39;t find it comfortable.  
         [0004]     Hearing protectors fall generally into two categories: active and passive. Passive devices simply block noise from entering the ear canal. Common foam ear plugs and most over-the-ear muffs are passive. In addition to blocking noise from reaching the ear, some active hearing protection uses external microphones to sample sound, amplifies the signal, and sends it to speakers where the user can hear the external sounds at a safe level. Noise canceling devices also fall into the active category. These devices use microphones to actively monitor what noise is getting past the protector. An electronic processor creates a correction signal that is amplified and emitted into the device. The correction signal then acts to negate the unwanted noise. Noise canceling protectors are effective when used in constant noise environments but do not adequately handle sudden loud sounds, such as a gun shot.  
         [0005]     Electronic hearing protection exists for the shooting industry in three basic types: muffs, behind-the-ear (BTE), and in-the-ear (ITE). Ear muff styles are worn over the ears during shooting. Some active type muffs incorporate eternal microphones that sample sound and send the signals to circuitry that amplifies the signal and sends it to speakers. Separate volume controls are typically on each earpiece. Muffs are very effective and generally inexpensive, but muffs are large in size. Size is the biggest problem for a person discharging a firearm as many times the stock of the firearm contacts the muffs upon mounting the shotgun to the shoulder. Muffs can also be quite hot to wear. Proper fit is a big factor in the effectiveness of any type of hearing protection. This proper fit is often interfered by shooting or safety glasses.  
         [0006]     Separate electronic ITE plugs are also available. They too have volume controls on each plug, which requires a user to manually balance the sound levels. While satisfying desirable size characteristics, the cost of this type ear protection is often considerable. The small controls on these devices make adjusting and balancing the volume difficult.  
         [0007]     Behind-the-ear active hearing protectors are also available. Usually, a small module connects to an ear plug via a nylon tube. The tube routes from the ear plug, over the ear, to a module nested behind the ear. Housing the electronics behind the ear provides more room for circuitry, which generally lowers cost below the cost of comparable ITE units. Although effective, BTE devices, like muffs, interfere with eyeglass use and require separate controls to operate left and right channel volume.  
         [0008]     Therefore, the firearms field could benefit from a device that provides the following: proper hearing protection from loud gun discharges, the amplification of desired sounds and suppression of others, and a comfortable fit for extended use while avoiding interfering contact with a firearm. Additionally, attaching such a device to a carrier such as a hat further provides for larger and additional battery storage capability.  
       SUMMARY OF THE INVENTION  
       [0009]     A hearing protector is disclosed that amplifies desirable sounds, such as voices, but suppresses loud sounds such as shotgun discharges. Furthermore, the hearing protector does not interfere with the positioning of a shouldered firearm.  
         [0010]     The present invention is a design where a microphone, at least one speaker, and other circuitry is packaged in a housing that could be affixed to, for instance, the underside of a cap brim, thereby providing a method of a greatly reduced cost as compared to the prior art. Alternatively, rather than having the speaker or speakers mounted in the housing, the speaker or speakers are selectively mountable close to the ears of the wearer.  
         [0011]     If speakers are mounted remote from the ears, tubing from the module may be routed through the hat, exiting the sides, where it is connected to earphones, much like a stethoscope. Mono or stereo models can be provided. Alternatively, if speakers are selectively mountable close to the ears of the wearer, electrical wiring is used to transmit representative electrical signals from the module to the speakers, which can be selectively engaged with a wearer&#39;s ear.  
         [0012]     The hearing protection unit may be coupled with a conventional hat, such as a baseball cap. Additionally, the hearing protection unit can be coupled with hard hats such as those used in industrial applications. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]      FIG. 1  is a block diagram of a first preferred electrical circuit according the present invention.  
         [0014]      FIG. 1   a  is an electrical schematic of a preferred audio pick-up incorporated into the first preferred electrical circuit of the present invention.  
         [0015]      FIG. 1   b  is an electrical schematic of a preferred volume controller incorporated into the first preferred electrical circuit of the present invention.  
         [0016]      FIG. 1   c  is an electrical schematic of a preferred amplifier incorporated into the first preferred electrical circuit of the present invention.  
         [0017]      FIG. 1   d  is an electrical schematic of a preferred monitor incorporated into the first preferred electrical circuit of the present invention.  
         [0018]      FIG. 1   e  is an electrical schematic of a preferred power supply incorporated into the first preferred electrical circuit of the present invention.  
         [0019]      FIG. 1   f  is an electrical schematic of a preferred audio compression circuit incorporated into the first preferred electrical circuit of the present invention.  
         [0020]      FIG. 2  is a top perspective view of a preferred embodiment of a hearing protection device of the present invention.  
         [0021]      FIG. 3  is a bottom perspective view of a preferred embodiment of a hearing protection device of the present invention.  
         [0022]      FIG. 4  is a top perspective view of a second preferred embodiment of a hearing protection device of the present invention.  
         [0023]      FIG. 5  is a bottom perspective view of a third preferred embodiment of a hearing protection device of the present invention.  
         [0024]      FIG. 6  is a top perspective view of the third preferred embodiment in use while disposed on a user&#39;s head. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0025]     Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structures. While the preferred embodiment is hereinafter described, the details may be changed without departing from the invention, which is defined by the claims.  
         [0026]      FIG. 1  depicts a block diagram of an electronic circuit  10  embodiment to be used with the hearing protection device of the present invention. Generally, the circuit  10  has an audio pick-up  11  electrically coupled to at least one speaker  12 . Optionally, a second speaker  12 ′ may be added to the circuit  10 . More specifically, the circuit  10  comprises a volume controller  13 , an amplifier  14 , a power supply  15 , the audio pick-up  11 , an audio compressor  17 , a monitor  16 , and the speaker  12 . The power supply  15  provides the system operating voltage  22  and a constant battery voltage  23  to the volume controller  13 . The volume controller  13  provides a power-on signal  17  to the power supply  15  and also provides volume control  18  to the amplifier  14  to increase or decrease the level of the signals  21  provided to the speaker  12 . The audio pick-up  11  provides electrical signals  20 , which are representative of audio signals received by the pick-up  11 , to the compressor  17 . The compressor  17  provides compressed audio signals  24  to the amplifier  14 . The amplifier  14  provides controlled electrical outputs  21  to the speakers  12 ,  12 ′ which are representative of the signals  24  received from the compressor  17  based on the configuration of the amplifier  14  as manipulated by the volume controller  13 .  
         [0027]     During times when ambient sound is at desired levels, the amplifier  14  outputs signals  21  at a selected volume to the speaker  12 . However, it is desirable to suppress loud noises that may otherwise harm the wearer&#39;s ear. To prevent harm, the circuit  10  is provided with a means for modifying the signals  21  provided to the speaker  12 . The circuit  10  is also provided with a monitor  16 , which preferably controls the means for modifying the signals  21 . The means for modifying, as depicted, is preferably an amplifier shut down control input  143 . The monitor  16  samples the signals  24  presented to the amplifier  14  signal inputs  141 , 142 . Upon detecting undesirable signal levels, the monitor  16  communicates a signal  19  to the means for modifying  143  to deactivate the outputs  146 , 147  of the amplifier  14 . Upon return of acceptable ambient noise levels, or after a predetermined period of time, or both, the signal  19  is deactivated and the amplifier  14  is allowed to once again provide volume-controlled electrical outputs  21  to the speakers  12 , 12 ′. While the compressor  17  is not needed to achieve amplification deactivation, the compressor  17  is desirable to provide the relatively constant signal level to the amplifier  14 . Without the compressor  17 , the outputs  113 , 114  of the audio pick-up  11  may be directly coupled to the signal inputs  141 , 142  of the amplifier  14 , to which the monitor inputs  161 , 162  would remain coupled.  
         [0028]     As seen in  FIG. 1   a,  and also with reference to  FIG. 1 , the audio pick-up  11  preferably comprises a microphone  111  and appropriate bias circuitry including a low noise, high gain transistor amplifier  112 . In this embodiment, the audio pick-up  11  output is replicated  113  to interface to both inputs  173 , 174  of the compressor  17 . In this manner, a mono audio signal is eventually supplied to a single speaker  12 , or both speakers  12 ,  12 ′. Optionally, a second microphone could be included in the audio pick-up  11 . Inclusion of a second microphone enables two-channel stereo sound. If a second microphone is included, a similar bias circuit to that of the first microphone  111  is preferably used. Further, in an embodiment using two microphones, instead of capacitively coupling both outputs  113 , 114  together, one output  114  is capacitively coupled to the second microphone bias circuit in a manner similar to the coupling of the other output  113  to the first microphone  111  bias circuit.  
         [0029]     Referring now to  FIG. 1   b,  and also with reference to  FIG. 1 , an electrical schematic of an embodiment of the volume controller  13  is shown. Generally, the volume controller  13  preferably controls activation of the circuit  10  and volume control of the amplifier  14  outputs. The preferred volume controller  13  comprises a volume increase switch  131 , a volume decrease switch  132 , a power-on signal output  133 , a clock signal output  134 , a volume increase/decrease signal output  15 , a pair of oscillators  136 , and a battery power input  137 . Although various interfaces could be used, the volume switches  131 , 132  are preferably push-button, normally open switches, each having one pole connected to the battery power input  137  and the other pole connected to one of the provided oscillators  136 . Depression of either the volume increase switch  131  or the volume decrease switch  132  activates the power-on output  133  to indicate to the power supply  15  that the circuit  10  requires system power  22 . In addition to sending the power-on signal  133 , the depression of the volume increase switch  131  activates one of the oscillators  136 , which sets the volume increase/decrease signal  135  to an appropriate volume increase logic level and causes an oscillating signal on the clock output  134 . Similarly, depression of the volume decrease switch  132  activates the other of the oscillators  136 , which sets the volume increase/decrease signal  135  to the appropriate volume decrease logic level and causes an oscillating signal on the clock output  134 . Release of either depressed switch  131  or  132  causes the clock output  134  to cease oscillation, thereby preventing further volume change. Furthermore, continued depression of either switch  131  or  132  causes an increase or decrease in volume, respectively, with each oscillation, or predetermined number of oscillations, of the active oscillator  136 . The volume controller  13  described to this point would be most applicable in a circuit  10  that incorporates a digital volume control for the amplifier  15 . Alternatively, the volume controller  13  could consist of a simple potentiometer that may include an OFF position. In This instance, the volume controller would still control power supply to the circuit  10 , but the variable resistance of the potentiometer would vary the biased gain of preferably an analog volume controlled amplifier  14 .  
         [0030]     Turning to  FIG. 1   c,  and also with reference to  FIG. 1 , a preferred amplifier  14  is shown. One embodiment of the invention utilizes a standard headphone amplifier  14 , which basically comprises two op-amps  140 , wherein the two inputs  141 , 142  of the amplifier  14  are tied to op-amp  140  inverting inputs through appropriate bias circuitry. The amplifier  14  may be an integrated circuit, such as an LM4811 available from National Semiconductor Corporation of Santa Clara, Calif., or constructed of discrete electronic components. The outputs  146 , 147  of the amplifier  14  are electrically coupled to the speakers  12 , 12 ′. If only one speaker  12  is used, only one output  146  or  147  may be desired. Furthermore, the amplifier  14  preferably includes a digital volume controller  149 , which includes as inputs a clock  144  and a signal  145  representative of volume increase or decrease. Preferably, the digital volume controller  149  provides a plurality of digital steps of amplification. While any number of combinations could be employed, it is preferable to have sixteen digital steps, wherein each step causes a 3 dB change in the volume. Generally, the digital volume controller  149  controls the gain of the op-amps  140 . The amplifier  14  further includes shutdown circuitry  148 , which is tied to a shutdown input  143 . When the shutdown input  143  is activated, the shutdown circuitry  148  biases the op-amps amps  140  such that the amplifier outputs  146 , 147  are deactivated. Alternatively, if an analog amplifier  14  is used and the amplifier  14  is not provided with shutdown circuitry  148 , the monitor  16 , as described below, could effectively prevent amplification in a number of ways.  
         [0031]     An electrical schematic of an embodiment of the monitor  16  is shown in  FIG. 1   d.  The monitor  16  comprises preferably the same number of inputs  161 , 162  as the number of amplifier  14  inputs employed, a shutdown signal output  163 , and a switch  164 . If any input  161  or  162  exceeds a predetermined level, the switch  164 , which is normally turned on, will turn off, thereby causing the shutdown signal output  163  to activate. The shutdown signal output  163  is preferably connected to the means for modifying the signals  21  presented to the speakers  12 , 12 ′, in this case a shutdown signal input  143  of the amplifier  14 . Activation of the shutdown control input  143  of the amplifier  14  prevents amplification and passage of an amplified signal to the speakers  12 , 12 ′.  
         [0032]     As described above, the means for modifying the signals  21  presented to the speakers  12 , 12 ′ is the shutdown input  143  of the amplifier  14 , which ceases amplification by deactivating the amplifier  14 . However, the signals  21  could be modified in other ways. For instance, the monitor  16  could prevent amplification by interrupting the inputs to the amplifier  14  after sensing a predetermined signal  24  level, in which case the means for modifying may be a simple transistor switching circuit. Additionally, rather than ceasing amplification completely, the means for modifying the signals  21  could reduce the gain of the amplifier  14 . To employ this functionality, a volume override circuit may be controlled by the monitor  16 . Finally, the monitor  16  may simply disconnect or interrupt the signals  21  presented to the speaker  12 . This arrangement may be accomplished by methods well known in the art for switching signals.  
         [0033]      FIG. 1   e  provides an electrical schematic of an embodiment of the power supply  15 . The power supply includes a battery  154 , a power-off switch  155 , a power-on latch  157 , a power switch  156 , a power-on signal input  151 , a battery power output  152 , and a system voltage output  153 . The battery  154  is provided to power the circuit  10 . Generally, prior to circuit activation by the volume controller  13 , the battery  154  is disconnected from the circuit  10 , except the volume controller  13 , because the power-on latch  157  is deactivated and the power switch  156  is turned off. The battery power output  152 , however, is active and is connected to the volume controller  13 . When the volume controller  13  activates the power-on signal input  151 , which is preferably done by the user depressing either volume switch, the power-on latch  157  is turned on. In turn, the power switch  156  turns on, thereby providing the battery  154  voltage to the rest of the circuit  10  via the system voltage output  153 . To conserve battery  154  power, the circuit  10  may be deactivated. While this may be accomplished in a variety of ways, preferably a power-off switch  155  is used. The power-off switch  155  is a push-button, normally open switch. Depression of the switch  155  causes the power-on latch  157  to deactivate, thereby turning off the power switch  156 . Thus, battery  154  power is removed, once again, from the entire circuit  10 , except the volume controller  13 .  
         [0034]      FIG. 1   f  provides an electrical schematic of an embodiment of the compressor  17 . The compressor  17  comprises outputs  171 , 172 , inputs  173 , 174 , signal amplifiers  175 , and a gain controller  176 . Generally, as is understood in the art, the compressor  17  provides relatively constant outputs  171 , 172 , within a predetermined range. These outputs  171 , 172  are fed to the amplifier  14  and are sampled by the monitor  16 . The compressor inputs  173 , 174  are coupled to the outputs  113 , 114  of the audio pick-up  11 . To accomplish the relatively constant output over a predetermined range, the compressor  17  gain controller  176  modifies the gain of the amplifiers  175  in a relationship that is inversely proportional to the signal level provided at the inputs  173 , 174 . That is, for weaker input levels, the gain controller  176  will increase the gain of the amplifiers  175 . Conversely, the gain controller  176  will decrease the gain of the amplifiers  175  when the levels of the inputs  173 , 174  increase. If the outputs  171 , 172  increase beyond a threshold level, the signals  21  provided to the speaker  12  will be modified, as described above.  
         [0035]     It is to be appreciated that the sound generated by the speaker  12  is to be conveyed to at least one ear of the wearer of the device. Such transmission of sound can be accomplished in a variety of ways, two of which are herein described.  
         [0036]     Referring to  FIGS. 2-3 , an embodiment  100  of a hearing protection device of the present invention is shown, wherein the speaker  12  is placed distal the ear of the wearer. For example, the speaker  12  may be mounted on the same substrate as the circuit  10 . Preferably, the circuit  10  is packaged in a single housing  105  that may be affixed to an underside of a brim of a cap  101 . Where the speaker  12  is distal the ear of the wearer, it is preferable to use tubing  102  to convey the sound created by the speaker  12  to the ear of the wearer. That is, the speaker  12  is aurally coupled to the ear of the wearer via the tubing  102  and earpieces  106 . If desirable to convey sound to both ears of the wearer, multiple lengths of tubing  102  can be used.  
         [0037]     The tubing  102  extends from the housing  105  and is routed through the cap  101 , exiting the sides, where it is connected to the earpieces  106 . As described above, mono or stereo models can be provided. Preferably, the tubing  102  is coupled to a tee-fitting  104  offering a split for additional tubing  102 . An example of the tubing  102  used is 1/16″ inside diameter tubing. Proximate the ears of the wearer, the tubing  102  is either formed or pieced in a manner that guides the tubing  102  down from the cap  101  and towards the ears of the wearer and connected to earpieces  106 .  
         [0038]     Referring now to  FIG. 4 a  top perspective view of a second preferred embodiment of a hearing protection device of the present invention is shown. Like the first embodiment of  FIGS. 2 and 3 , this embodiment has a speaker placed distal the ear of a wearer. In this embodiment, rather than place a housing under the brim of a hat, a microphone/speaker assembly  205  is coupled on the outside of the cap  101 , preferably on the front of the cap  101 , where designs or slogans may be emblazoned on the assembly  205 . In this arrangement, tubing  102  can either be routed through the cap  101 , as shown, and then in the area proximal to the ear, or routed about the hat  101  and routed rearward (not shown). As will be appreciated, the microphone/speaker assembly  205  could also be coupled to different portions of the cap  101 , such as the top of the brim, or the back, in accordance with manufacturer preference.  
         [0039]     Instead of using tubes to convey sound from a distal speaker as in the previous embodiments, the speakers  12 , 12 ′ may generate the sound proximate the ears. Referring to  FIGS. 5-6 , an embodiment  300  of a hearing protection device of the present invention is shown, wherein the speakers  12 , 12 ′ are placed proximate the ears of the wearer. In this embodiment, a housing  305  contains the preferred electrical circuit  10  with the exception of the speakers  12 , 12 ′ which are mounted away from the housing  305  but in electrical communication with the rest of the circuit  10  via electrical wires  302 . The electrical wires  302  are preferably supported against the hat  101  with, for example, supporting tubular members  304 . The speakers  12 , 12 ′ are coupled also with the earpieces  306 . Retainer clips  307  are attached to the hat  101  to provide anchor points for the speakers  12 , 12 ′ and the earpieces  306 .  
         [0040]     To use the device  300 , a user places the hat  101  on his or her head, removes the speakers  12 , 12 ′ and earpieces  306  from the retainer clips  307  and places the earpieces  306  in his or her respective ears and powers the device on.  
         [0041]     One advantage of the present invention is that typical in-the-ear and behind-the-ear units that normally utilize small batteries can be employed. These are typically zinc-air batteries that start discharging as soon as they are installed. Preferably, a larger module can also be provided, using typical watch batteries (or larger) for much longer periods of intermittent use.  
         [0042]     Another advantage of the present invention is that the device may be coupled with a desirable type of hat. Therefore, for use in a warm environment, the device may be coupled with a ventilated cap; for use in a cold environment, the device may be coupled with an insulated cap. Furthermore, as employed in certain embodiments, the present invention disrupts neither the shouldering of a firearm nor the wearing of shooting or safety glasses.  
         [0043]     The foregoing is considered as illustrative only of the principles of the invention. Furthermore, 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. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims.