Abstract:
The invention provides a method of replacing, exchanging or repositioning pickups and other accessories used by stringed instruments from the back of the musical instrument.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to provisional patent application Ser. No. 61/400,515 filed Jul. 28, 2010 by Jim Severson for METHODS OF PLAYING A STRINGED INSTRUMENT AND THE STRINGED INSTRUMENT. 
    
    
     BACKGROUND OF THE INVENTION 
     The invention relates to the use of pickups and other accessories for a stringed instrument, such as electric hollow or solid body guitars, acoustic-electric guitars, electric bass guitars, electric violins, mandolins, ukuleles, and the like. 
     BRIEF SUMMARY OF THE INVENTION 
     The invention provides a method of replacing, exchanging or repositioning pickups and other accessories used by stringed instruments, such as electric solid body and hollow body (acoustic-electric) guitars, electric bass guitars, electric violins, mandolins, ukuleles, and the like. 
     A pickup is used to convert the oscillations of the strings into electrical impulses for subsequent conversion into sound. 
     It is often desirable to change the location or type of pickup in a guitar or other stringed instrument. The invention provides a method of quickly and easily installing or changing one or more pickups in a guitar. 
     The pickup or pickups are installed from the back of the guitar through an opening with a closure, cover or door. Various pickups and other accessories can easily be installed and removed in this method. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         FIG. 1  is a top view of the invention. 
         FIG. 1A  is a top view of the invention. 
         FIG. 2  is a cross-sectional view of the invention taken along doted line  2  in the direction of the arrows. 
         FIG. 3  is a perspective view of the back of the invention. 
         FIG. 4  is a top view of the invention. 
         FIG. 5  is a top view of the invention. 
         FIG. 6  is a bottom view of the invention. 
         FIG. 7  is a top view of another embodiment of the invention. 
         FIG. 8  is a bottom view of a further embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows a portion of a stringed instrument  100 , such as a guitar. The guitar  100  has a front body portion  110 , strings  200  and a pickup  10  positioned beneath the strings. The guitar  100  is not fully shown. The bridge portion is to the left of the front body portion at  112 , and the neck portion is to the right of the front body portion at  111 . Pickup  10  has a mounting plate  11  and is mounted in the pickup cavity  120 . Spacer plates  12  are provided to fill the opening in the pickup cavity  120  in the front body portion  110 . Spacer plates  12  and mounting plates  11  are held in place by screws  40 B or other type of fasteners passing through mating holes  32  in retainer plate  30  and secured in the guitar body. The fasteners can be plastic push-in friction fasteners, knurled or wing headed screws, etc. 
     Only one pair of screws or fasteners  40 B need to be used to hold the spacer plates, accessory plates and mounting plates in position since the plates abut and are held in place by the guitar body at either the front right body portion  111  or the front left body portion  112 . 
     The screws/fasteners  40 B are shown holding each space plate  12  and mounting plate  11  in place; however only one set of screws/fasteners are needed if they are used to hold the spacer plate to the left in position. The other spacer plate and pickup plate are held in place by the left or neck portion of the guitar body. Alternatively, two plates could be held in place with the fasteners. 
       FIG. 1A  shows a guitar  100  with a front body portion  110 , bridge portion  112  and a neck portion  111 . The pickup cavity  120  has one pickup  10  and two spacer plates  12  in the shown variation of the invention. 
       FIG. 2  shows the pickup cavity  120  formed in the guitar. Pickup cavity  120  provides an access for installing pickup  10  from the back body portion  130  of the guitar. Cavity  120  is provided in the guitar body to provide access to install and replace the pickups from the rear of the guitar. Cavity  120  is shown as having an inner guitar surface  121 - 126  which is shown as having a metal liner to provide an electromagnetic shield. The inner guitar surface has an outer wall  121 , a ledge  122  upon which pickup mounting plate  11  slides and seats, an intermediate wall  123 , a bottom wall  124 , an inner wall  125  and a higher bottom wall  126 . 
     A metal spacer of aluminum  20  is provided on the ledge  122  between the ledge and the metal of the pickup mounting plate  11  to provide a wear surface if the liner is a coating, thin foil or other material that may be worn away during the insertion and removal of the pickups, etc. The spacer  20  can be held in place on the ledge  122  by countersunk screws or other fastening means. 
     A retainer plate  30  holds the pickup  10  in place on the spacer  20  and ledge  122 . The retainer plate  30  has holes  31  with screws  40 A holding the plate to the guitar body. Retainer plate  30  also has holes  32  with screws  40 B that hold the pickup mounting plate  11  to the retainer plate, the spacer  20  and the ledge  122 . Spacer  20  has holes matching holes  32  in retainer plate  30 . Screws  40 B used in the holes  32  can be replaced by other types of fasteners, such as plastic Pine Tree® fasteners. The screws  40 B are shown as going through the spacer  20  and into holes drilled into the guitar  100 . Where the fasteners go into the guitar body, it is preferred to use a threaded insert attached to the guitar body to receive the screw. 
     The electromagnetic shield/liner on walls  121 - 126  of pickup cavity  120  and under the retainer plate  30  can be an electrically conductive paint, such as Stewart-Mac Donald Conductive Shielding Paint, sold by the Stewart-Mac Donald Company, Athens, Ohio. Other ways of lining the cavity are to provide copper or aluminum tape, a metal foil with glue, etc. The spacer  20  can be aluminum. The electrically conductive paint on the cavity  121 - 126 , the metal spacer  20 , the metal mounting plates  11  and/or spacer plates  12  provide an electrically conductive/shielded volume to suppress electromagnetic interference. 
       FIG. 3  shows the back body portion  130  of the guitar  100 . The back body portion  130  has a cover plate  131  which provides access to the pickup cavity  120  through an opening  132  in the back portion of the guitar. The cover plate  131  is opened in the direction of the arrow. The cover plate  131  can be magnetically mounted to the back portion of the guitar. The cavity  120  has end wall  129 . 
     To remove the pickup  10 , the cover plate  131  is removed. The screws  40 B or other fasteners, such as Pine Tree® or Christmas Tree® fasteners are removed from the retainer plate  30 . The electrical connectors are unplugged from the pickup. Then, each spacer plate  12  is removed through the opening  132  by sliding it along the spacer  20  on ledge  122  until it reaches the opening  132  and is then removed through the opening  132 . Then, the pickup mounting plate  11  is slid along the spacer  20  on ledge  122  until it reaches the opening  132  in the back portion of the guitar and then is removed through the opening  132 . 
     To install the pickup, the pickup mounting plate  11  is introduced through the opening  132  and slid along the spacer  20  on ledge  122  until it reaches the front body portion  111  at one end of the ledge  122 . The spacer plates  12  are then added to close the open space to the left of the pickup and secured with fasteners  40 B. Cables are connected to the pickup before introducing the pickup  10  into cavity  120 . The cable connections are covered in  FIG. 6 . 
     Opening  132  extends across the cavity  120  from the outer wall  121  to the opposing outer wall  121 . The spacer  20  is also missing at the opening  132 . Therefore, the pickup mounting plate  11  can be removed from the guitar through the opening  132 . The dimensions of the opening  132  will be larger than the length of the mounting plate  11 . The opening  132  can be larger than the width of the spacer plate  12  or the pickup mounting plate  11  so that different size plates can be introduced therethrough. The opening  132  can have various positions, such as right, left or center of the cavity  120  (normal bridge, middle and neck pickup positions). 
       FIG. 4  shows a pickup  10  mounted in a different position by removing screws  40 B, removing the spacer plates  12  if present, sliding the pickup mounting plate  11  to the new position and then repositioning one set of screws or other type of fastener  40 B in the retainer plate  30  and mounting plate  11 . In this embodiment, the electromagnetic shielding can be provided by using shielded pickups. 
       FIG. 5  shows two pickups  10  mounted on either side of a spacer plate  12  on the guitar by screws or fasteners  40 B. Only one set of fasteners  40 B need be used. The fasteners  40 B would be used in the pickup plate or spacer plate at the end of the guitar having the opening  132 . 
       FIG. 6  shows multiple, different pickups can be used at the same time on the guitar, such as three or more pickups. For example, the pickups could be a Humbucker™ neck (rhythm) pickup, a single coil middle pickup and an angled “stacked” Humbucker™ bridge (lead) pickup of single coil width. 
     Control cavity electrical cables  300  which are fed through a hole into the control cavity (not shown) connect to intermediate cables  301  with female and male ends which connect to the pickup cables  302  on the pickups. Intermediate cables  301  extend pickup cables  302  and are easily connected to cables  300  and  302 . The control cavity cables  300  connect to controls in the control cavity. 
     Optionally, hook and loop fasteners  400 A,B can be added to the cables  301  and/or  302  and to the mounting plates  11  to hold the cables in place. Alternatively, only a single hook and loop fastener can be used at the opening  132  to secure all of the cables. The cables can be color or otherwise coded to provide easy matching of the corresponding/correct cables. The cables can have multi-pin, USB or other suitable connectors. 
     Connections between the pickup cables  302 ,  301  and the corresponding control cavity cables  300  are made in the opening  132  before the pickups are removed or after the pickups have been installed. The intermediate cables  301  are plugged into the pickup cables  302  before introducing the pickup  10  into the cavity  120 . 
       FIG. 7  shows an accessory plate  13  with accessories  500 , such as two rows of electrical slide switches, provided on the plate which is positioned between two pickup mounting plates  11 . The plates  11 , 13  are all held in place by Pine Tree® fasteners  40 B in the pickup plate on the left and the guitar body on the right. 
     The accessories/switches  500  which can alter the wiring configuration of dual coil pickups are mounted on a circuit board attached to the accessory plate  13  which may be electrically connected to the pickups by jacks on the circuit board. 
     Preferably, the switches can be connected to the pickups by using patch or connecting cables which would extend to the opening  132  for ease of connection at the point. The cables can be color or otherwise coded to help making the proper connections. 
     The accessory plate  13  can be provided in any unused position. The preferred position of the pickup switching accessory plate  13  is in the middle pickup position. 
     The accessory  500  on the accessory plate  13  may be an electronic processor with a touch or pressure sensitive display that may be patched through in a similar manner to switching plate. 
     The processor on the accessory plate can have reference software applications, such as a guitar tuner, a chord library, a scale library, etc. 
     Further, various software applications similar to those currently available for the iPhone® or iPod®, such as the Amplitube® 2,3 applications from ikmultmedia.com and the Guitar Toolkit® and other applications from agilepartners.com, may be incorporated through the use of the appropriately sized and modified processor with a display. The processor may be provided with cables to provide an output or be a wireless processor. 
     Wireless pickups incorporating radio transceivers may be mounted with pickup mounting plates thereby requiring no connecting cables and processed with a wireless processor mounted on an accessory plate or a wireless processor mounted in the control cavity. 
       FIG. 8  shows an alternate embodiment of the invention in which the openings  132  A, B to the back of the guitar are divided into three compartments  132 A for three pickups which are the pickup cavities in this embodiment and a compartment  132 B for the wires or cables. Openings  132 A extend through to the front of the guitar. The outlines of the opening  132 A,B are shown in dotted lines since they are behind cover plate  131 . The openings  132 A,B are spaced from the cover plate  131  by enough distance to provide space for the wires or cables and the pickup mount fasteners. 
     Cover plate  131  has a coin slot  131 A to help in removing the cover plate. Magnets  131 B are mounted on the two walls separating the three compartments  132 A for holding the cover plate  131  in place. 
     The control cavity  133  (shown in dotted lines) communicates with the compartments  132 A,B to feeds the wires/cables to the pickups. The control cavity  133  can have any shape and has a cover plate  131  which can be held in place with magnets or other holding means. The control cavity  133  can contain a pickup selector, a volume control for each pickup, a tone control for each pickup, etc. Cables/cords will exit the guitar from the control cavity through a hole in the control cavity (not shown). 
     While the disclosure has been described with reference to several embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the disclosure without departing from the essential scope thereof. Therefore, it is intended that the disclosure not be limited to the particular embodiments disclosed as the best mode contemplated for carrying out this disclosure, but that the disclosure will include all embodiments falling within the scope of the appended claims. 
     Various changes and modifications to the embodiments herein chosen for purposes of illustration will readily occur to those skilled in the art. For example, the pickups can be of various types and can be in any combination. The pickups can be electromagnetic, optical, active, passive, etc. The pickup cavity  120  may not need to be shielded if the pickups are shielded. A cosmetic plate can be attached to the retainer plate  30 .