Patent ID: 7544873

Claim:
A stringed musical instrument comprising a head portion, a neck portion, a body portion, a plurality of generally parallel strings attached to the head portion and to the body portion, and a bridge member which engages the strings in a position adjacent to the body portion, the improvement comprising a mounting fix plate attached to the body portion; a movable plate (a) having the bridge member, (b) having a vertical portion positioned further from the head portion than the bridge member, (c) that is slideable with respect to the mounting fix plate, and (d) a first bracket extending from the vertical portion away from the bridge member and having a first hook receiving device to receive a first hook from a biasing device; a retainer (a) positioned a predetermined distance from the first bracket (b) having a U shape configuration having an exterior surface and an interior surface, and (c) the exterior surface of the U shape configured retainer has a bottom side that connects to the mounting fix plate, a riser side that faces the movable plate, a top side, a right edge and a left edge; a track adjuster (a) is positioned in the interior surface, (b) has a second hook receiving device that receives a second hook from the biasing device, (c) has at least one tension screw that contacts the interior surface of the riser side to maintain and/or adjust the distance of the track adjuster from the moving plate to adjust or maintain the desired force of the biasing device, and (d) has at least one stopper screw that contacts the first bracket to adjust or maintain the predetermined minimum distance between the first hook receiving device and the second hook receiving device; a lever interconnected to a swing link, the swing link is interconnected to the brackets and has a portion contact the mounting fix plate, so (a) when the lever is moved down toward the musical instrument, the biasing devices increase in tension and the moving plate moves away from the retainer; and (b) when the lever is in the relaxed state or moved up away from the musical instrument, the biasing device's tension is not altered but when the lever is moved up the moving plate moves toward the retainer and the track adjuster moves within the interior surface of the retainer to retain the predetermined minimum distance between the first hook receiving device and the second hook receiving device.