Locking connector

A locking connector to connect ends of a pair of tubes to each other, the locking connector comprising:

• a first connector portion that is provided at an end of one of the tubes and comprises a male thread portion on an outer circumferential surface;
• a second connector portion that is provided at an end of the other tube and is connected to the first connector portion;
• a lock ring that is formed in an annular shape covering a periphery of the second connector portion, comprises, on an inner circumferential surface thereof, a female thread portion to be screwed onto the male thread portion and a movement restricting portion to restrict movement of the second connector portion toward a base end side, and by screwing the female thread portion onto the male thread portion, locks the first connector portion and the second connector portion in a connected state while pushing in the second connector portion toward the first connector portion by the movement restricting portion;
• not less than one projecting portion formed on one of an outer circumferential surface of the second connector portion or an inner circumferential surface of the lock ring;
• and
• a slope portion that is formed on the other of the outer circumferential surface of the second connector portion or the inner circumferential surface of the lock ring and comprises not less than one inclined surface formed at an angle with respect to a circumferential direction about an axis of rotation of the screwing so that a diameter gradually increases along a direction of rotation of the screwing,
• wherein as the female thread portion is screwed onto the male thread portion, the projecting portion rotates relative to the slope portion, the projecting portion interferes with the inclined surface with the rotation, and loosening of the lock ring is thereby prevented.