Patent Publication Number: US-10309124-B2

Title: Method and apparatus for sanitizing door knobs or door handles

Description:
CROSS REFERENCE TO RELATED APPLICATION(S) 
     The present application is a divisional of and claims the priority of U.S. patent application Ser. No. 15/341,400, titled “METHOD AND APPARATUS FOR SANITIZING DOOR KNOBS OR DOOR HANDLES”, filed on Nov. 2, 2016. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to improved methods and apparatus for sanitizing door knobs or door handles. 
     BACKGROUND OF THE INVENTION 
     While there are existing patents that try to solve the spreading of germs on a door knob/handle, none are practical or commercially viable. Many known previous devices are stand-alone units that replace an existing door knob/handle. This presents at least two problems: first, it is not a quick and easy install, eliminating a portion of the population that is willing to install the device themselves; secondly, it limits the market considerably, as individuals are forced to accept the aesthetics of a device that contain the packaged door knob/handle instead of using their existing door knob/handle in a retrofit application. For instance, some previous patents are stand-alone devices only in the shape of a doorknob. This limits the market as those who have door handles will likely not use that product. 
     Previous patents only addressed one side of the door knob/handle. While an additional device can be placed on the opposite side of the door, there is no direct communication or sequencing that allows this device to effectively eliminate microorganisms on both sides of the door, given the possibility that only one side of the door is sanitized defeating the purpose of the product; stopping the spreading of germs through contact with door knobs/handles. To provide a pragmatic and effective solution, both sides of the door would need to be sanitized. 
     Many previous patents disclose devices which are mechanical in nature which presents maintenance issues, increases the weight, and adds to bulkiness of the device while consuming significantly more energy. 
     Using an infrared sensing device as indicated in a previous patent is an imperfect solution, as the dominant hand of the person opening the door could be on the opposite side of the sensing device and hence not sensed. Infrared sensing devices have other issues that can lead to devices disclosed in previous patents not functioning as intended all the time. 
     SUMMARY OF THE INVENTION 
     In at least one embodiment, an electronic doorknob/handle sanitizer apparatus is provided designed and engineered to combat the spreading of germs using UVC (ultraviolet C) light to destroy microorganisms on a door handle or door knob surfaces. UVC light has a wavelength typically between one hundred and two hundred and eighty nanometers, inclusive, and a photon energy between 4.43 and 12.4 eV (electronvolts), or between 0.710 and 17.987 aJ (attojoules), and is short-wave germicidal, and typically fully absorbed by the atmosphere and the ozone layer. 
     The apparatus may include two sequenced communicating sanitizers that operate on the inside and outside of any given door. The apparatus may be used on existing doorknobs/handles in a retrofit application. The apparatus may include an accelerometer that detects movement on a door; when open or closed, and communicates that signal to the controller located on an electronic circuit board of one of the sanitizers. That sanitizer in turn may communicate via Bluetooth to the sanitizer located on the opposite side of the door enabling the built in LED (light emitting diode) UV-C lights of both sanitizers on a five-second delay. A Lithium Ion battery may be used to power the LED UV-C lights for about twenty seconds sanitizing the surface of the doorknob/handle. In at least one embodiment, the apparatus has been found to be 99% effective at destroying microbes at a distance of three inches. The UV-C light is projected in a conical shape towards the doorknob or handle and the apparatus may have an under mounted mirror to reflect UV light towards the underside of the doorknob/handle. The apparatus may be affixed to a door surface using two-sided removable tape identified in drawings, sitting approximately one and a half inches above a doorknob surface. Using two-sided tape allows the device to be removable and easily reapplied if necessary. The apparatus may operate using a rechargeable lithium-ion battery. The LED UV-C bulb used may have a estimated life of 10,000 hours. 
     One or more embodiments provide a true retrofit application, where there is no need to change or modify the existing door; no need to sacrifice function above form. In addition, one or more embodiments allow both sides of the door knob/handle to be sanitized in a sequenced fashion while eliminating redundant controllers and motion sensing devices. 
     One or more embodiments of the present invention eliminate redundancy, miniaturizes the application, and creates a layer of safety (to not expose people&#39;s hands to UV light) not previously addressed. By sequencing the sanitizing of the door knob/handle by a programmed controller communicating via Bluetooth or equivalent communication standard, and activated by a built-in accelerometer, the devices on either side of the door synchronize the dispersion of UV-C light on the door knobs/handles. One or more embodiments create a more practical, efficient, safe, and effective deliverance of a sanitized door knob/handle. 
     One or more embodiments of the present invention are electronic with virtually no moving parts. Energy consumption is reduced, improving battery life along with the application of LED UVC light instead of implied low-pressure sodium lights. LED UV-C lights also eliminate a need for a ballast which would have had to be included in previous designs. 
     One or more embodiments of the present invention are more energy efficient, require no maintenance, and are considerably lighter allowing the device to be affixed using double sided tape. One or more embodiments of the present invention can be easily removed and relocated without any damage to the door. 
     One or more embodiments of the present invention provide an accelerometer, which, in some embodiments, is a perfect solution to accurately sense when the door needs to be sanitized, as a force is applied whenever a door moves open or closed. The accelerometer responds to this force (movement) and is a preferred way that an apparatus can accurately detect when sanitizing needs to be applied. 
     The underside reflector is incorporated to reflect the sterilizing UV light from the device onto the underside of the door knob/handle. The reflector is conforms to the circular shape of the mounting plate/bracket of the door knob or handle. With the reflector, the device properly addresses sterilizing the entire door knob/handle and not just the top surface. 
     In at least one embodiment of the present application an apparatus is provided comprising a first apparatus for producing light, wherein the first apparatus for producing light includes a first device for detecting movement of a door; wherein the first apparatus for producing light includes a first set of one or more light sources; wherein the first set of one or more light sources are configured to turn on when the first device for detecting movement of the door detects movement of the door; and wherein the first set of one or more light sources are configured to produce short wavelength ultraviolet light. 
     The first device for detecting movement of the door may include an accelerometer. The apparatus may include the door itself; and the first device for detecting movement of the door may be fixed to the door. 
     The apparatus may include a computer processor; and a computer memory; wherein the computer memory has stored therein a threshold value; and wherein the computer processor is programmed to compare a value of a detected signal produced by the first device for detecting movement of the door in response to movement of the door, with the first threshold value and to cause the first set of one or more light sources to be turned on if the value of the detected signal exceeds the threshold value. 
     The first apparatus for producing light may have housing, and the first set of one or more light sources may be fixed to and inside of the housing and configured so that light from the first set of one or more light sources is directed at a first doorknob of the door, when the first set of one or more light sources is turned on, and the housing is fixed to the door. 
     The overall apparatus may include a second apparatus for producing light; wherein the second apparatus for producing light includes a second set of one or more light sources; wherein the second set of one or more light sources are configured to turn on when the first device for detecting movement of the door detects movement of the door; and wherein the first apparatus for producing light and the second apparatus for producing light are separate and are configured to be fixed to opposite sides of the door; and wherein the first and second set of one or more light sources are configured to produce short wavelength ultraviolet light. 
     In at least one embodiment, the overall apparatus may include a first apparatus for reflecting light; wherein the first apparatus for producing light and the first apparatus for reflecting light can be fixed to the door and configured so that light emanates from the first apparatus for producing light towards the first apparatus for reflecting light, and is at least partially reflected by the first apparatus for reflecting light back towards the first apparatus for producing light. 
     In at least one embodiment, the first apparatus for producing light has a housing having a width; the first apparatus for reflecting light has a housing having a width; and the width of the first apparatus for producing light is substantially the same as the width of the first apparatus for reflecting light. 
     In at least one embodiment the housing of the first apparatus for producing light is fixed to the door, at about one and half inches from the first door knob of the door. The first apparatus for producing light and the first apparatus for reflecting light may be fixed to the door, so that the first door knob is between the first apparatus for producing light and the first apparatus for reflecting light. 
     In at least one embodiment a method is provided including projecting first light towards a first doorknob of a door in response to movement of the door; and wherein the first light is short wavelength ultraviolet light. The method may include projecting second light towards a second doorknob of the door in response to movement of the door; wherein the first doorknob and the second doorknob are located on opposite sides of the door; and wherein the second light is short wavelength ultraviolet light. 
     In at least one embodiment, the steps of projecting first light towards the first doorknob of the door and second light towards a second doorknob of the door are performed only if the movement of the door is sufficient to cause a threshold to be exceeded. 
     A value concerning the threshold may be stored in computer memory, and a computer processor may compare a value of a signal generated by the movement of the door with the value of the threshold stored in computer memory to determine if the threshold has been exceeded. The signal generated by the movement of the door may be generated by an accelerometer. The method may include reflecting at least part of the first light back towards the first doorknob. 
     The first light may emanate from a first housing wherein the first housing has a width; wherein the at least part of the first light is reflected back from a second housing separate from the first housing; and the method may further include fixing the first housing and the second housing on the door, so that the first doorknob is between the first housing and the second housing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows front view of an overall apparatus including a door, a first door handle, a first apparatus produces light, and a first apparatus which reflects light, in accordance with an embodiment of the present invention; 
         FIG. 2  shows a side view of part of the door in  FIG. 1 , the first apparatus which produces light, the first apparatus which reflects light of  FIG. 1 , the first door handle of  FIG. 1 , a second apparatus which produces light, and a second apparatus which reflects light, and a second door handle in accordance with an embodiment of the present invention; 
         FIG. 3  shows a closeup front view of the first apparatus which produces light of  FIG. 1 , the first apparatus which reflects light of  FIG. 1 , and the first door handle of  FIG. 1 ; 
         FIG. 4  shows a rear, left, and bottom perspective view of a cover of the first apparatus which produces light of  FIG. 1 ; 
         FIG. 5  shows a front, right, and bottom perspective view of a housing of the first apparatus which produces light, wherein the housing is shown without various internal components; 
         FIG. 6  shows a front, right, and bottom perspective view of the housing of  FIG. 5 , with various internal components shown in simplified form; 
         FIG. 7  shows a front, top, and right perspective view of the first apparatus which reflects light; 
         FIG. 8  shows a block diagram of components for the first apparatus which produces light; and 
         FIG. 9  shows a block diagram of components for the second apparatus which produces light. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows front view of an overall apparatus  1  including a door  2 , a first door handle or door knob  20 , a first apparatus  10  which produces light, and a first apparatus which reflects light  40 , in accordance with an embodiment of the present invention. The door  2  has a front surface  2   a , and a left edge  2   b . The door may be a solid rectangular door, and may have a width, W 1 , which may be about one and one half inches and a length L 1 , which may be about eighty three inches. The first apparatus which produces light  10  may be temporarily fixed to the door surface  2   a  by an adhesive or by Velcro (trademarked), or by a double sided tape. In at least one embodiment using a double sided tape to fix the first apparatus which produces light  10  to the door is preferred. In at least one embodiment, each of the first apparatus which produces light  10  and the first apparatus which reflects light  40  is configured to have a width, W 2  which is about the same as a diameter D 2  of the door knob or handle  20 . This allows light, such as ultraviolet light in at least one embodiment, such as preferably UVC light (short wavelength ultraviolet light) emanating out of the first apparatus which produces light  10  in the direction D 1 , from a bottom opening or region  11   e , to substantially encompass the entire diameter D 2  of the door knob  20 , to be reflected back by reflecting surface  42  of the first apparatus which reflects light  40 , and to further encompass the door knob  20  so that the entire or substantially the entire door knob  20  has light directed it on it from the combination of the apparatus  10  and the apparatus  40 . 
     In at least one embodiment, the light emanating from end or side  11   e  from the apparatus  10  and reflected back the apparatus  40 , is typically UVC light, and typically kills all or substantially all germs on all surfaces of the door knob  20 , except possibly the face of the door knob  20 , wherein the face of the door knob  20  typically does not come in contact with an individual&#39;s hand. Having the width W 2  of the apparatus  10  and the apparatus  40  be the same as the door knob  20  diameter D 2  also creates an aesthetically pleasing look. 
     The door  2  may be a standard size door, such as having a width W 1  of about three feet, and a length L 1  of about six and one half feet. The overall apparatus  1  may have a length L 2  which may be larger than the width W 2 . In at least one embodiment, it is critical that the first apparatus for producing light  10  be a distance D 4 , an inch and a half or less away from the first door knob  20  to provide optimum killing of germs on door knob  20 , and also to provide clearance for an individual&#39;s hand to turn the door knob  20 . In at least one embodiment, a ½ inch is necessary to provide adequate clearance for an individual&#39;s hand. 
       FIG. 2  shows a side view of part of the door  2  in  FIG. 1 , the first apparatus  10  which produces ultraviolet light of  FIG. 1 , the first apparatus which reflects light  40 , the first door handle  20  of  FIG. 1 , a second apparatus  14  which produces light, a second apparatus which reflects light  50 , and a second door handle  30  in accordance with an embodiment of the present invention. The edge  2   b  of the door  2  is visible in  FIG. 2 . The first apparatus  10  includes a cover  11 , and a housing  12 , in which various components are located. The second apparatus  14  includes a cover  16  and a housing  15  in which various components are located. The first apparatus  10  and the second apparatus  14  may be identical. The first door handle  20  may be connected by axles  22  and  32  to the second door handle  30 . The first door handle  20  and/or the second door handle  30  may turn the locking or latching door mechanism  24  in a known manner. The first and second door handles  20  and  30  may be any known door handles or door knobs, and the locking or latching mechanism may be any known locking or latching mechanism. The first apparatus for reflecting light  40  and the second apparatus for reflecting light  50  may be identical, which each having a reflecting surface or device, such as reflecting surface or device  42  for apparatus  40 , and a similar or identical reflecting surface or device  52  for apparatus  50 . 
     The first apparatus  10  may emit UV light in the direction D 1 , and this light may disinfect the door knob  20  or at least part of the door knob  20 , such as a top edge portion. At least part of the light from the first apparatus  10 , is directed on the reflecting surface or device  42  and reflected back towards the door knob  20  to disinfect at least part of the door knob  20 , such as a bottom edge portion. 
     The second apparatus  14  may emit UV light in the direction D 3 , and this light may disinfect the door knob  30  or at least the part of the door knob  30 , such as a top edge portion. At least part of the light from the second apparatus for producing light  14 , is directed onto the reflecting surface or device  52  and reflected back towards the door knob  30  to disinfect at least part of the door knob  30 , such as a bottom edge portion. 
       FIG. 3  shows a closeup front view of the first apparatus which produces light  10 , the first apparatus which reflects light  40  and the first door handle  20 . The cover  11  of the first apparatus  10  may have a top edge  11   b , a front surface  11   g , a left side or wall  11   c , a right side or wall  11   a , and a bottom region or opening  11   e . There are two flat surfaces which has a width W 3 . The curved top edge  11   b , may have a radius of curvature of R 1 , which may be about ⅝ inches. The distance from the top of top edge  11   b , and the start of flat sides or walls  11   c  and  11   a  may be L 3 , which may be about ¼ of an inches. The sides or walls  11   c  and  11   a  may have a length L 4  of about four inches. The width W 2  of the cover  11  may be about two and one half inches, which may be about the same as the diameter D 2  of the door knob  20 , to provide coverage of the door knob  20  with emitted ultraviolet light from the bottom region or opening  11   e.    
     The distance between the top of bottom region or opening  11   e  and the bottom end of sides or walls  11   c  and  11   a  may be about L 5 , which may be about one half of an inch. The apparatus for reflecting light  40  may have a width W 2  which is equal to the width of the apparatus for producing light  10  to allow light emanating from opening  11   e  to be receiving sufficiently at reflecting surface  42 , and to allow for an aesthetically pleasing appearance with respect to door knob  20 . 
       FIG. 4  shows a rear, left, and bottom perspective view of a cover  11  of the first apparatus which produces light  10  of  FIG. 1 .  FIG. 4  shows the flat sides or walls  11   a  and  11   c , and top edge or wall  11   b .  FIG. 4  shows inner surface  11   d , and chamber  11   f  surrounded by walls  11   a ,  11   b ,  11   c , and opening, entrance or end  11   e.    
       FIG. 5  shows a front, right, and bottom perspective view of a housing  12  of the first apparatus which produces light  10 , wherein the housing  12  is shown without various internal components. The housing  12  includes walls or sides  12   a ,  12   b ,  12   c ,  12   d ,  12   e , and  12   f . There is an opening  12   g , between walls  12   e  and  12   f . There is a chamber or region  12   h  surrounded by walls  12   a ,  12   b ,  12   c , and  12   d . There is a surface  12   i.    
       FIG. 6  shows a front, right, and bottom perspective view of the housing  12  of  FIG. 5 , with various internal components.  FIG. 6  shows  10   a , which may be a rechargeable lithium ion battery or other battery or power source, a wall  10   b , a circuit board with various components  10   c  shown further in block diagram format in  FIG. 8 , LEDs  10   e ,  10   g , and  10   i , which emit light, such as UVC light in at least directions D 1   a , D 1   b , and D 1   c  through a lens  10   k . In addition, there are reflecting surfaces  10   d ,  10   f ,  10   h , and  10   j , which may serve to concentrate the light from LEDs  10   e ,  10   g , and  10   i , in the directions D 1   a , D 1   b , and D 1   c.    
       FIG. 7  shows a front, top, and right perspective view of the first apparatus which reflects light  40 , and the reflecting or mirror surface  42 . 
       FIG. 8  shows a block diagram  100  of components for the first apparatus which produces light  10 . The first apparatus which produces light  10 , may include battery  10   a , CPU, central processing unit or computer processor  102 , accelerometer  104 , transmitter/receiver  106 , relay  108 , and LEDs  10   e ,  10   g , and  10   i.    
     The battery  10   a  may be a lithium ion rechargeable battery. The transmitter/receiver  106  may be a Bluetooth device which provides wireless communications. The accelerometer  104  does upon detecting movement of the door  2  in  FIG. 1 , produces a door movement signal to the CPU  102 . In response to the door movement signal, the CPU  102  causes the LEDs  10   e ,  10   g , and  10   i  (or some other light source, typically for producing UVC light for disinfecting) to activate and to thereby produce and emanate light from opening  11   e  towards door knob  20 , then to reflecting surface  42  of apparatus  40 , which reflects light back towards the door knob  20 . The light, typically UVC light, disinfects, or substantially disinfects the door knob  20 . 
     The relay  108  is connected to the LEDs  20   e ,  20   g ,  20   i , and can be a manual switch for allowing the LEDs  20   e ,  20   g , and  20   i  to turn on when activated by the accelerometer. 
       FIG. 9  shows a block diagram  200  of components for the second apparatus which produces light  14 . The second apparatus which produces light  14 , may include battery  14   a , a block of components  10   c , which includes CPU, central processing unit or computer processor  202 , accelerometer  204 , transmitter/receiver  206 , relay  208 , and LEDs  60   e ,  60   g , and  60   i.    
     The battery  14   a  may be a lithium ion rechargeable battery. The transmitter/receiver  206  may be a Bluetooth device which provides wireless communications. The accelerometer  204  does upon detecting movement of the door  2  in  FIG. 1 , produces a door movement signal to the CPU  202 . In response to the door movement signal, the CPU  202  causes the LEDs  60   e ,  60   g , and  60   i  (or some other light source, typically for producing UVC light for disinfecting) to activate and to thereby produce and emanate light from opening, analogous to opening  11   e , for first apparatus  10 , towards door knob  30 , then to reflecting surface  52  of apparatus  50 , which reflects light back towards the door knob  30 . The light, typically UVC light, disinfects, or substantially disinfects the door knob  30 . 
     The relay  208  is connected to the LEDs  60   e ,  60   g ,  60   i , and can be a manual switch for allowing the LEDs  60   e ,  60   g , and  60   i  to turn on when activated by the accelerometer. 
     The first apparatus for producing light  10  may communicate with the second apparatus for producing light  14  via transmitter/receiver  106  in  FIG. 8  and transmitter/receiver  206  in  FIG. 9 . The first apparatus for producing light  10  may be programmed in its CPU  102 , to be a master device and the second apparatus for producing light  40 , in its CPU  202  may be programmed to be a servant device. The CPU  202  and accelerometer  204  are optional on the servant device, if desired, as a simple controller or simplified CPU  202  can replace these components to relay the signal from the Transmitter/Receiver  206  to the LEDs  60   e ,  60   g , and  60   i , to activate the LEDs  60   e ,  60   g , and  60   i  to disinfect the door knob  30  or at least a large portion of the door knob  30 . The CPU or computer processor  102  may communicate with the CPU  202  or a simplified version of the CPU  202 , via the transmitters/receivers  106  and  206 , to cause the CPU  202  to activate the LEDs  60   e ,  60   g , and  60   i.    
     A sequence of operations may be executed in accordance with one or more embodiments of the present invention. 
     In an activation mode, the accelerometer  104  of component  10   c  of the first apparatus for producing light  10  may detect a force of the opening or closing of the door  2 . The CPU  102  may include a computer processor and computer memory, and may have stored in the computer memory a minimum threshold value for a minimum threshold signal corresponding to a minimum threshold force to be detected by the accelerometer. The detected minimum force indicates that the door  2  has been operated. 
     A detected signal from the accelerometer, due to a force or movement of the door  2 , is sent to the CPU  102  and the computer processor of the CPU  102  compares the signal to the stored minimum threshold value in computer memory of the CPU  102 . If the value of the signal, such as the amplitude, exceeds the stored minimum value in computer memory, then the CPU  102  starts a programmed sequence, wherein instructions for the programmed sequence are stored in computer memory of the CPU  102 . 
     The CPU  102 , as programmed, initiates a delay, which may be five seconds, to allow a person for example, touch the door knob  20 , open the door  2 , touch the door knob  30 , and close the door  2 . I.e. The CPU  102  waits until a person&#39;s hand is not touching the door knob  20  or  20 , and then activates the LEDs  10   e ,  10   g , and  10   i , and the LEDs  60   e ,  60   g , and  60   i , to disinfect the door knobs  20  and  30 . 
     In at least one embodiment the LEDs  10   e ,  10   g ,  10   i ,  60   e ,  60   g , and  60   i  are activated and remain in an on state for twenty seconds to thoroughly disinfect the door knobs  20  and  30 . 
     The CPU  102  may send a signal via transmitter/receiver  106  and transmitter receiver  206  to cause the LEDs  60   e ,  60   g , and  60   i  to be activated and on at the same time as the LEDs  10   e ,  10   g , and  10   i . The transmitter/receivers  106  and  206  may be or may be replaced by Bluetooth (trademarked) or for example, some other short range wireless devices. 
     The CPU  202  may be simplified to be a relay or may be replaced by a relay which detects a control signal from the CPU  102 , such as via voltage, and activates LEDs  60   e ,  60   g , and  60   i , and causes them to remain on for twenty seconds as a result of transmission of signal from CPU  102  for twenty seconds, or as a result of the CPU  202  causing activation to continue for twenty seconds after receiving a start signal. 
     In at least one embodiment the LEDs  10   e ,  10   g ,  10   i , and  60   e ,  60   g , and  60   i  may remain on for twenty seconds and then all shut off. 
     The apparatus for producing light  10 , which may be a master unit, may then enter a secondary mode for up to thirty minutes as programmed in a computer memory of the CPU  102 . 
     In at least one embodiment, when the secondary mode, if the accelerometer  104  detects a force of the opening or closing of the door, i.e. by producing a signal having for example an amplitude greater than a minimum threshold value as programmed in computer memory of the CPU  102 , then the previous activation mode process may be repeated. I.e. five second delay (or some other appropriate delay) to allow the person to open and close the door, and then a disinfecting state for twenty seconds, or some other appropriate time period. 
     Following the secondary mode, the master unit, or the first apparatus for producing light  10  may enter a standby mode. In at least one embodiment, if the first apparatus for producing light  10  is in secondary mode for over thirty minutes, without the completion of the cycle, the master unit or the first apparatus for producing light  10  may revert back to standby mode. 
     In standby mode, the first apparatus for producing light  10  may wait for detection of any motion of opening or closing the door  2  that exceeds a minimum threshold. In addition, in at least one embodiment, a computer processor of the CPU  102  may be programmed to activate the LEDs  10   e ,  10   g ,  10   i ,  60   e ,  60   g , and  60   i  for twenty seconds, or an appropriate period of time, to substantially disinfect the door knobs  20  and  30 , if no signal exceeding the threshold has been received from the accelerometer  104  in six hours. For example, if the door  2  has not been used in six hours, or some other reasonable time period of non use, the CPU  102  may be automatically programmed to disinfect or substantially disinfect the door knobs  20  and  30 . After disinfecting, the CPU  102  may again enter into standby mode. 
     Although the invention has been described by reference to particular illustrative embodiments thereof, many changes and modifications of the invention may become apparent to those skilled in the art without departing from the spirit and scope of the invention. It is therefore intended to include within this patent all such changes and modifications as may reasonably and properly be included within the scope of the present invention&#39;s contribution to the art.