Abstract:
Healthcare industry pillow speaker cables and interfaces are disclosed. Pillow speaker cables communicatively couple a pillow speaker to another device. Pillow speaker cables comprise four wires. The first wire and the second wire comprise a data bus for communicating data to and from the pillow speaker. The third wire and the fourth wire comprise an audio line and an audio return line for transmitting audio information to and from a speaker in the pillow speaker.

Description:
REFERENCE TO RELATED CASE 
       [0001]    The present application is based on and claims priority of U.S. provisional patent application Ser. No. 61/086,297, filed Aug. 5, 2008, the content of which is hereby incorporated by reference in its entirety. 
     
    
     BACKGROUND 
       [0002]    Audio signal are commonly transmitted across a distance. For instance, in a short-term or long-term care facility, a patient or resident may be in a room with a television. In such a case, it may be desirable to transmit the television&#39;s audio output to a location closer to the patient or resident where it can be converted to sound. Generating the sound closer to the resident or patient may make listening to the sound more convenient and may also reduce overall noise levels that could disturb others (e.g. a patient or resident in a neighboring room). 
       SUMMARY 
       [0003]    An aspect of the disclosure relates to pillow speaker cables and interfaces for the healthcare industry. In one embodiment, a pillow speaker cable for communicatively coupling a pillow speaker to another device comprises four wires. The first wire and the second wire comprise a data bus for communicating data to and from the pillow speaker. The third wire and the fourth wire comprise an audio line and an audio return line for transmitting audio information to and from a speaker in the pillow speaker. 
         [0004]    These and various other features and advantages that characterize the claimed embodiments will become apparent upon reading the following detailed description and upon reviewing the associated drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]      FIG. 1  is a schematic diagram of a wireless audio system. 
           [0006]      FIG. 2-1  is a perspective view of wireless audio system transmitter arrays. 
           [0007]      FIG. 2-2  is a top down view of wireless audio system transmitter arrays. 
           [0008]      FIG. 3  is a block diagram of a wireless audio system transmitter. 
           [0009]      FIG. 4  is a block diagram of a wireless audio system receiver. 
       
    
    
     DETAILED DESCRIPTION 
       [0010]    Certain embodiments of the present disclosure include systems and methods of wirelessly transmitting and receiving an audio signal. In one embodiment, a wireless signal is transmitted across an indirect path. For example, a wireless signal is generated and transmitted by a transmitter and is then reflected off from one or more surfaces or objects before reaching a receiver. This indirect transmission may be advantageous over other systems such as systems that require a direct line-of-sight between a transmitter and a receiver. For instance, in a line-of-sight system, a signal may be blocked from reaching a receiver if an object passes between the transmitter and the receiver. Also, in a line-of-sight system, the physical positioning or placement of the receiver and transmitter are commonly limited. For example, the receiver may need to be positioned at a certain angle or height relative to the transmitter to receive a signal. In at least some embodiments of the present disclosure, the indirect transmission of signals allows for a signal to travel around an object that passes between the transmitter and receiver, and allows for the signal to successfully reach the receiver. Similarly, the indirect transmission of signals illustratively allows for greater flexibility in the positioning of the receiver relative to the transmitter. For instance, a receiver could be positioned such that its sensor faces away from the transmitter. The receiver illustratively receives a signal by receiving a signal that has been reflected from its original direction to the direction of the receiver&#39;s sensor. 
         [0011]    Certain embodiments of the present disclosure illustratively provide additional benefits such as, but not limited to, reduced power consumption, improved system troubleshooting and set-up capabilities, improved signal transmission interfaces, and enhanced operational capabilities (e.g. the ability to operate multiple wireless systems in one room). These and other advantages and benefits will become apparent in the following more detailed description of embodiments. 
         [0012]      FIG. 1  is a block diagram of an illustrative wireless audio system. The audio system includes a transmitter  300  that receives an audio signal from an audio content source  10 . Audio source  10  includes any type of device that produces an audio signal. Illustrative audio sources include, but are not limited to, televisions, computers, media players (e.g. an optical media player), and video game systems. As will be described in greater detail later, transmitter  300  converts an audio signal received from source  10  into a wireless signal  12  that is transmitted to receiver  400 . Receiver  400  converts the wireless signal back into an audio signal and illustratively relays the audio signal to pillow speaker  20 . Pillow speaker  20  has a speaker  22  that utilizes the audio signal to generate sound that can be listened to by a user. 
         [0013]    In an embodiment, wireless signal  12  comprises infrared (IR) light produced by one or more transmitter light emitting diodes (LEDs)  302 . In single LED embodiments, the single LED is illustratively a relatively powerful LED in that it is capable of generating enough light to essentially fill or flood a room. In embodiments having multiple LEDs, the LEDs are optionally grouped into one or more arrays.  FIG. 2-1  is a perspective view of an illustrative transmitter LED array system  200 . System  200  includes a first LED array  210  and a second LED array  220 . Array  210  illustratively has a base plane  212  that positions LEDs  302 , and array  220  has a base plane  222  that positions LEDs  302 . Each array illustratively has a height  250  and a length  260 . In the embodiment shown in  FIG. 2-1 , each array has two rows along height  250  and four columns along length  260 . Or, in other words, each array is a 2 by 4 array. Embodiments of the present disclosure include any number of LEDs per a row and any number of LEDs per a column. Embodiments also include any number of arrays and any number of LEDs per an array. 
         [0014]      FIG. 2-2  is a top down view of system  200 .  FIG. 2-2  shows that arrays  210  and  220  are illustratively angled away from each other (i.e. their LEDs point in different directions). Array  210  is rotated clockwise by an angle  280  and array  220  is illustratively rotated counterclockwise by an angle  290 . Angles  280  and  290  may either be the same or different. In an embodiment, angles  280  and  290  are both between twenty to forty degrees. Embodiments are not however limited to any particular angles and embodiments include all angles. For instance, in another embodiment, LED arrays are angled toward each other as opposed to being angled away from each other as is shown in  FIGS. 2-1  and  2 - 2 . 
         [0015]    It should be noted however that in multiple LED embodiments, that the placement or positioning of LEDs is not limited to arrays. Embodiments of the present disclosure include any arrangement of multiple LEDs. For example, LEDs are illustratively not placed in rows and columns, and are instead illustratively placed in other types of patterns (e.g. a starburst pattern). LEDs may also be placed in more or less randomly scattered positions. 
         [0016]    LEDs  302  illustratively generate IR light along a path that is perpendicular or normal to their base planes (e.g. normal to base planes  212  and  222  in  FIG. 2-1 ). LEDs  302  may also generate additional light. For example, in an embodiment for illustration purposes only and not by limitation, LEDs  302  generate light normal to their base plane and also generate a cone of light from plus thirty-five degrees from normal to minus thirty-five degrees from normal. 
         [0017]    Returning to  FIG. 1 , transmitter  300  and receiver  400  are illustratively operated in spaces having a ceiling, a floor, and/or one or more walls. Transmitter  300  and receiver  400  are also illustratively operated in spaces having one or more objects between a transmitter  300  and a receiver  400 . In such a case, at least some of the signals  12  generated by LEDs  302  are reflected off from surfaces of the ceiling, floor, walls, and/or objects. In such an embodiment, signals  12  take a variety of different paths in going from transmitter  300  to receiver  400 . This may be advantageous over other systems such as those that require a direct line-of-sight. For instance, in a line-of-sight system, there may be only one signal path between a transmitter and a receiver. If the one path is obstructed, for example by a person walking between the transmitter and the receiver, the receiver will not receive the signal. However, in systems such as that shown in  FIG. 1 , signals  12  take multiple different paths in traveling from transmitter  300  to receiver  400 . As long as all of the paths are not obstructed, the receiver will still receive a signal. 
         [0018]    Embodiments of the present disclosure may also provide advantages over other systems such as those that use other types of transmission techniques. For instance, radio frequency (RF) waves could perhaps be used. Other transmission techniques such as RF waves may however travel through walls, ceilings, floors, etc. In environments having multiple wireless audio systems, such as in long or short term residential care facilities, this could lead to signal interference between systems in multiple rooms. This issue however is not present in systems utilizing LEDs. The light produced by LEDs is illustratively contained within the room where the light is generated. Thus, there is either no interference or reduced interference as compared to other potential systems such as those that use RF waves. 
         [0019]      FIG. 3  is an illustrative block diagram of transmitter  300 . Transmitter  300  includes an audio input connector  304  that receives an audio signal from audio source  10  in  FIG. 1 . Input connector  304  is illustratively configured to accommodate any type of audio input. In one embodiment, input connector  304  is illustratively a ⅛″ headphone jack and various types of audio sources  10  are connected to transmitter  300  utilizing an appropriate adapter. Transmitter  300  also includes an audio type selector  306 . Selector  306  is illustratively adjusted by a user to correspond to the type of audio input being used by the transmitter. For example, if transmitter  300  is receiving an audio signal from a headphone line, selector  306  is adjusted to correspond to receiving input from a headphone line. Selector  306  is illustratively either manually controlled by a user or is self-sensing in that it automatically determines the type of audio source that is connected. Similar to connector  304 , selector  306  is illustratively able to accommodate for any type of audio input. 
         [0020]    The audio signal from input  304  is then passed to a load or impedance matching module  308 . Module  308  receives the indication of the audio input type from selector  306 . Module  308  illustratively converts various types of audio input signals such that it provides an equivalent signal to signal conditioner  310  regardless of the audio source. For instance, an audio signal from left and right RCA lines may have a different peak-to-peak voltage than an audio signal from a headphone line. Module  308  illustrative converts the signals such that they have the same peak-to-peak voltages. Or, in other words, module  308  normalizes different voltage amplitudes of incoming signals to maximize bandwidth. Signal conditioner  310  then filters the audio signal. Conditioner  310  illustratively has a high pass filter and a low pass filter. The high pass filter removes any high frequency noise from the signal, and the low pass filter removes low frequency signals such as direct current noise. 
         [0021]    The audio signal is then passed to signal detector  312 . Detector  312  determines if there is an audio signal being received from an audio source  10 . For example, transmitter  300  may not be receiving a signal if audio source  10  is turned off. In one embodiment, detector  312  compares a voltage of the audio signal from conditioner  310  to a reference voltage. If detector  312  determines that an audio signal is not being received, transmitter  300  illustratively does not generate and transmit a wireless signal. This feature may be advantageous in that components of transmitter  300 , such as but not limited to LEDs  302 , may have a limited life time (i.e. they stop producing light after a certain amount of usage). By not generating a wireless signal when there is no audio signal, the lifetime and/or reliability of transmitter  300  may be improved. Additionally, not generating a wireless signal may also reduce power consumption. 
         [0022]    Signal detector  312  is optionally connected to an indicator light  314  (also shown in  FIG. 1 ). Indicator light  314  illustratively indicates the status of transmitter  300 . For example, in an embodiment, light  314  is off (i.e. no light is produced) when transmitter  300  is turned off or is not receiving power. Light  314  flashes (i.e. intermittently produces light) when transmitter  300  is turned on but is not generating and transmitting a signal, and light  314  is continuously on when transmitter  300  is generating and transmitting a wireless signal. Receiver  400  optionally has a corresponding indicator light  414  (shown in  FIGS. 1 and 4 ). As will be discussed later in greater detail, lights  314  and  414  are illustratively useful in troubleshooting, setting-up, or operating wireless audio systems. 
         [0023]    Following detector  312 , the audio signal is passed to signal modulator  316 . Modulator  316  converts the incoming audio signal into a signal that is used to produce the wireless signal. In an embodiment, the incoming audio signal is in the form of a varying voltage, and modulator  316  converts the varying voltage signal into a frequency based signal (i.e. a frequency modulated or FM signal). Modulator  316  illustratively includes a voltage-controlled oscillator that is utilized to produce the FM signal. In another embodiment, the incoming audio signal is converted into an amplitude modulated or AM signal. Embodiments of modulator  316  are not however limited to any specific methods or devices for modulating the incoming signal, and illustratively include any methods and/or devices. 
         [0024]    Transmitter  300  optionally includes a channel or frequency center selector  318 . Selector  318  is illustratively toggled or otherwise manipulated by a user to change the center frequency of the wireless signal produced by transmitter  300 . For example, transmitter  300  may have two channels, a channel one and a channel two. Channel one may correspond to frequencies of 110 to 90 kHz with a center frequency of 100 kHz. Channel two may correspond to frequencies of 60 to 40 kHz with a center frequency of 50 kHz. As will be discussed later, receiver  400  optionally includes a corresponding channel or frequency selector  418  (shown in  FIGS. 1 and 4 ). Selectors  318  and  418  allow for multiple wireless audio systems to be operated in one room. For instance, a first user in a room could use channel one, and a second user in the room could use channel two. This allows for the users to control and to listen to their own audio sources  10 . If there were not multiple channels (e.g. multiple center frequencies), operating more than one audio system in a room may be difficult or impossible due to the wireless signals from the multiple audio systems interfering with each other. Although the previous example discussed an embodiment having two channels, embodiments are not limited to any particular number of channels and illustratively include any number of channels (e.g. 1, 2, 3, 4, 5, 6, etc.). 
         [0025]    Following modulator  316 , the signal, which is illustratively a frequency modulated signal, is passed to LED driver  320 . Driver  320  powers and operates LEDs  302 . LEDs  302  are illustratively powered on and off (i.e. alternated between producing light and not producing light) such that the modulated audio signal is reproduced or converted into a light based signal. 
         [0026]    In an embodiment, LEDs  302  are infrared LEDs (i.e. they produce electromagnetic radiation having wavelengths from 750 nanometers to 100 micrometers). In one specific embodiment, LEDs  302  produce light having wavelengths of approximately 870 and/or 940 nanometers. Embodiments of LEDs are not however limited to those producing any particular wavelengths of light. 
         [0027]      FIG. 4  is a block diagram of receiver  400 . Receiver  400  includes a sensor  402 . Sensor  402  illustratively converts the light based signal from transmitter  300  into an electrical signal. In one embodiment, for illustration purposes only and not by limitation, sensor  402  is a semiconductor based photodiode that converts light into electrical current. In  FIG. 1 , sensor  402  is shown as facing away from LEDs  302 . This represents that sensor  402  illustratively indirectly receives a signal from transmitter  300  (i.e. it receives a signal that has been reflected off from one or more surfaces before reaching sensor  402 ). 
         [0028]    The electrical signal produced by sensor  402  is then transmitted to preamplifier  404 . Preamp  404  illustratively increases a voltage and/or current of the signal and passes it to signal demodulator  406 . Demodulator  406  converts or transforms the incoming signal. The signal is illustratively converted such that it is the same or similar to the signal that enters signal modulator  316  in  FIG. 3 . For example, in an embodiment, modulator  316  converts a voltage based signal (i.e. a signal that communicates data based on voltage manipulation) to a frequency based signal. Demodulator  406  illustratively receives the frequency based signal from preamp  404  and converts it back into a voltage based signal. 
         [0029]    As was previously mentioned, in an embodiment, receiver  400  includes a frequency center selector or channel selector  418 . Selector  418  is illustratively toggled or otherwise manipulated by a user to select the frequency center being utilized by transmitter  300 . In another embodiment, selector  418  is automated in that it self-senses an available transmission signal and selects the appropriate channel or frequency center. Selector  418  then sends an indication of the selected channel or center frequency to demodulator  406 . In an embodiment, demodulator  406  includes a phase lock loop. The indication of the selected channel or center frequency is illustratively utilized in setting the frequency of the phase lock loop reference signal. Consequently, if the setting of selectors  318  and  418  are the same, demodulator  406  is able to convert the incoming signal. However, if the settings of selectors  318  and  418  are different, the incoming signal is outside of the phase lock loop&#39;s “capture range” and demodulator  406  is not able to convert the incoming signal. In rooms in which multiple audio systems are in use, this feature may be advantageous in that it allows an audio system user to selectively listen to one of possibly several wireless signals being transmitted in the room. 
         [0030]    After the signal is demodulated, it is optionally passed to a signal conditioner  408 . Conditioner  408  illustratively includes a high pass filter and a low pass filter to remove high frequency noise and direct current noise. The signal is then passed to a transmitter processor or controller  410 . 
         [0031]    As was previously mentioned, receiver  400  illustratively has an indicator light  414  that corresponds to transmitter indicator light  314 . In an embodiment, indicator light  414  is communicatively coupled to and controlled by controller  410 . For instance, when controller  410  detects an incoming audio signal, indicator light  414  is powered such that it is continually on. When controller  410  is powered on and it does not detect an incoming audio signal, light  414  is powered intermittently (i.e. light  414  is a blinking or flashing light). When controller  410  is turned off or is not receiving power, light  414  is turned off. 
         [0032]    Transmitter indicator light  314  and receiver indicator light  414  may help in the operation, set-up, or troubleshooting of a wireless audio system. For instance, if a user is not hearing any sound from the audio system, the user can look at lights  314  and  414 . If light  314  is off or blinking, no wireless signal is being transmitted so any troubleshooting efforts should be first spent on obtaining a solid, continuous light from light  314 . However, if light  314  is continuously on and light  414  is off or blinking, this is an indication that a signal is being transmitted, but it is not being received by receiver  400 . Accordingly, troubleshooting efforts should begin with examining possible issues with receiver  400 . 
         [0033]    Controller  410  is illustratively communicatively coupled to a nurse call station  50  (shown in  FIG. 1 ) through a nurse call input connection point  412  and a nurse call interface  414 . In a long-term or short-term care facility, a nurse call station  50  may be placed near a patient or resident bed or other location. Station  50  allows for a user to speak and listen to a remotely located person through speaker  52 . A privacy light  58  is illustratively a red light that is turned on to indicate to a user that his or her speech may be heard by others. 
         [0034]    Nurse call station  50  also illustratively includes a user input pad or buttons  56 . User input  56  illustratively includes a button or other user input device that allows for a user to indicate that a nurse&#39;s attention is requested. User input  56  may also include other buttons or input devices. For example, user input  56  illustratively includes buttons to request for the attention of other persons or to request for specific services, such as but not limited to, requesting for pain medication or requesting for a nurse&#39;s assistant. After a user input  56  is selected, an acknowledgment light  60  is illustratively turned on by a remote user to acknowledge that they have received the request. User input  56  may also include environmental controls such as, but not limited to, controls for room lighting, heating, air conditioning, and raising or lowering a thermostat. Communications between station  50  and remote persons are illustratively facilitated through a communications connection  62 . In an embodiment, connection  62  is a serial data bus that illustratively connects multiple nurse call stations to one or more centralized remote locations (e.g. a nurse&#39;s office). 
         [0035]    Receiver  400  is also illustratively communicatively coupled to a pillow speaker  20  (shown in  FIG. 1 ) through a pillow speaker connection point  416 . Similar to nurse call station  50 , pillow speaker  20  is commonly positioned near a resident or patient. In at least certain embodiments, pillow speaker  20  differs from nurse call station  50  in that nurse call station  50  is mounted such that it has a fixed position and pillow speaker  20  is moveable. Also, as will become clear shortly, pillow speaker  20  may also include additional features not included in nurse call station  50 . 
         [0036]    In an embodiment, pillow speaker  20  has a user input pad or buttons  26 , a privacy light  28 , and an acknowledgement light  30 . These are illustratively the same or similar as nurse call station  50 &#39;s user input pad  56 , privacy light  58 , and acknowledgement light  60 , respectively. It should be noted however that pillow speaker  20  is not directly connected to a remote communications connection such as connection  62 . Instead, remote communications through pillow speaker  20  are illustratively first passed through receiver  400  and then relayed through nurse call station  50  to remote communications connection  62 . 
         [0037]    As was previously mentioned, pillow speaker  20  also includes a speaker  22 . Like nurse call station speaker  52 , speaker  22  is also able to generate and transmit sounds such that a user can communicate with a remote speaker such as, but not limited to, a nurse. Speaker  52  also generates sound from the wireless signal received and demodulated by receiver  400 . In an embodiment, if receiver  400  is receiving a signal from both the nurse call station and from a wireless signal, the signal from the nurse call station overrides the wireless signal such that the nurse call audio is produced by speaker  22 . This illustratively allows for a person to listen to an audio source  10  such as a television while still being able to receive important information such as medical information from a nurse or other care provider. Additionally, pillow speaker  20  optionally includes a headphone jack  34 . In an embodiment, a user may plug a headphone set into jack  34  and listen to the pillow speaker audio output through the headphone set instead of through speaker  22 . 
         [0038]    Pillow speaker  20  further includes an auxiliary user input pad or buttons  36 . Pad  36  illustratively includes controls for operation of audio source  10 . For instance, if audio source  10  is a television, pad  36  may include buttons for controlling the television channel and buttons for controlling the television volume (i.e. the volume of the sound coming from speaker  22  or through headphones connected to jack  34 ). Pad  36  may include additional buttons for operating other devices, such as but not limited to, lighting, heating and cooling, window blinds, and a radio. 
         [0039]    Returning again to  FIG. 4 , receiver  400  further includes a volume control selector  420 . A user illustratively utilizes selector  420  to select whether pillow speaker volume is to be controlled locally through receiver  400  or remotely through audio source  10 . When selector  420  is positioned or otherwise manipulated to indicate that volume is to be controlled remotely, pillow speaker  20  transmits a signal to audio source  10  through pillow speaker transmitter  38  (shown in  FIG. 1 ). When selector  420  indicates that volume is to be controlled locally, pillow speaker  20  does not transmit any signal to audio source  10 . Instead, controller  410  or another component of receiver  400  (e.g. an amplifying component) increases or decreases the volume of the sound produced by pillow speaker  20 . 
         [0040]    It should be noted that the volume control system described in the previous paragraph is advantageous in that it allows for a wireless audio system to accommodate a number of different audio sources  10 . For instance, some audio sources  10  may only provide an audio signal output that has a fixed volume. Other audio sources  10  may only provide an audio signal output having a variable volume. Audio systems having volume control selectors  420  are able to accommodate audio sources  10  having either type of output signal. 
         [0041]      FIG. 1  shows that pillow speaker  20  is communicatively coupled to receiver  400  through a cable  40 . In one embodiment, for illustration purposes only and not by limitation, cable  40  consists solely of six wires. Two of the six wires are an audio line and an audio return line that transfer audio information between pillow speaker  20  and receiver  400 . The next two wires are a power line and a ground line that facilitate an electric current to flow through and power components of pillow speaker  20 . The final two wires are for digital communications. In one embodiment, the final two wires are a two-wire serial data bus. The final two wires illustratively transfer all of the other information between pillow speaker  22  and receiver  400 . For instance, they transfer information from receiver  400  to pillow speaker  20  to actuate lights  28  and  30 , and they transfer information from pads  26  and  36  from pillow speaker  20  to receiver  400 . In an embodiment that utilizes a six wire cable  40 , receiver pillow speaker input connection point  416  illustratively has corresponding connection points that receive the six wire cable. 
         [0042]    In another embodiment of cable  40 , the audio return line and the power ground line are combined into one line, a power/audio common ground line. In this embodiment, cable  40  consists solely of five wires which further reduces the number of wires needed. 
         [0043]    It should be noted that the five and six wire/line embodiments of cable  40  described above and the corresponding simplified pillow speaker interfaces  416  illustratively reduce costs and increase reliability over other systems that may use more wires. Traditional pillow speaker connection cables typically included many more wires. For example, conventional pillow speaker wires may have three wires for television controls, two wires for each indicator light (e.g. lights  28  and  30  in  FIG. 1 ), and two wires for each switch (e.g. two wires for each of the several possible inputs for buttons  26  and  36  described above). This would often lead to cables such as cable  40  and interfaces such as interface  416  having sixteen to eighteen wires and connections points as opposed to the five or six described above. 
         [0044]    To this point, embodiments of receivers  400  and nurse call stations  50  such as those shown in  FIG. 1  have been described in the context of being two separate units. In another embodiment, receivers and nurse call stations are integrated together and built as one physical unit such that the one physical unit has the functionality of both receiver  400  and nurse call station  50 . In such an embodiment, the five or six wire cable  40  from pillow speaker  20  illustratively connects to a five or six wire interface in the combined receiver and nurse call station. This combination of receiver and nurse call station may reduce costs over separate systems and may also have other benefits such as reduced floor space requirements. 
         [0045]    As has been described above, certain embodiments of the present disclosure provide wireless audio systems that do not require a line-of-sight between a transmitter and a receiver. This is illustratively accomplished by reflecting one or more wireless signals such that they take an indirect path to reach the receiver. Additionally, some embodiments have arrays that create multiple wireless signals with multiple paths. If a path is obstructed, for example by a passing person or object, the receiver is still able to receive a signal so long as at least one of the paths is not obstructed. Furthermore, certain embodiments of the present disclosure illustratively provide additional beneficial features such as, but not limited to, indicator lights, signal detectors, channel selectors, and improved cable connections. 
         [0046]    Finally, it is to be understood that even though numerous characteristics and advantages of various embodiments have been set forth in the foregoing description, together with details of the structure and function of various embodiments, this detailed description is illustrative only. Those skilled in the art will recognize that changes may be made in detail, especially in matters of structure and arrangements of parts within the principles of the present disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.