Patent ID: 6018114
Filing Date: 2000-01-25
Classification: G10D

Abstract:
A rotary valve of a brass instrument comprising:a rotor, wherein a plurality of change-over paths are formed on an outer peripheral surface of the rotor to change over a tube length of a resonance tube while shaft portions are formed to respectively project from both of end faces of the rotor as its integral parts;a valve casing having a cylinder-like shape in which the rotor is inserted, wherein openings are formed at both ends of the valve casing and wherein a same bore diameter of the rotor is set to inner diameters of the valve casing along its longitudinal direction while an outer diameter of the rotor is set to be slightly smaller than an outer diameter of an outer race of the radial ball bearing;an implantation bottom which covers an opening of one end of the valve casing;an implantation upper cover which covers an opening of another end of the valve casing;a rotation base which is fixed to the rotor;a lever which rotatably moves the rotation base;radial ball bearings which are provided inside of the valve casing to rotatably support the shaft portions of the rotor respectively; anda depression member for depressing the rotor in its axial direction via the radial ball bearing, wherein the depression member is located with respect to either the implantation bottom or the implantation upper cover.