Patent ID: 6255571
Filing Date: 2001-07-03
Classification: G10D

Abstract:
A trombone comprisinga mouthpiece blown by a player,a bell flared from one end thereof toward the other end,a main tube defining a column of air and having a first sub-tube connected at one end thereof to said mouthpiece and a second sub-tube connected at one end thereof to said one end of said bell,a valve unit includinga casing defined by end surfaces spaced from one another and a side surface extending between said end surfaces and having a first port formed in one of said end surfaces and connected to the other end of said first sub-tube, a second port formed in the other of said end surfaces and connected to the other end of said second sub-tube, a pair of third ports formed in a first area in said side surface and a pair of fourth ports formed in a second area in said side surface,a guide member having a first air passage connected at both ends thereof to said third ports of said pair,a rotor rotatably accommodated in said casing and having a second air passage connected between said first port and one of said third ports at a first angular position and between said first port and one of said fourth ports at a second angular position, a third air passage connected between the other of said third ports and said second port at said first angular position and between the other of said fourth ports and said second port at said second angular position and an axis of rotation, said second air passage being spaced from said third air passage in a direction of said axis of rotation,a manipulator manipulated by said player so as to drive said rotor for rotation, anda bypass tube connected at both ends thereof to said fourth ports of said pair, wherein virtual tangential lines are respectively in contact with said second air passage and said third air passage, and angles between said axis of rotation and said virtual tangential lines are less than 90 degrees at any contact points along said second air passage and said third air passage.