Patent ID: 6677543
Filing Date: 2004-01-13
Classification: B60Q

Abstract:
A turn signal switch device comprising:a housing equipped with a cancel protrusion outward which rotates in accordance with a steering wheel operation; a cam surface formed within the housing; first biasing unit for applying a biasing force toward the cam surface; a holder rotatably mounted to the housing; an operating lever integrally provided in the holder, and provided extending outwardly of the housing; a first cam integrally provided in the holder; a second cam which abuts the first cam in a direction toward a rotation path of the cancel protrusion; a first cancel lever integrally formed in the second cam, which is engaged with and mounted to the housing so as to be displaceable and rotatable until the rotation path of the cancel protrusion is reached; a second biasing unit which applies a biasing force so as to displace the first cancel lever in accordance with a displacement in an abutted position between the first cam and the second cam toward the rotation path of the cancel protrusion; and a second cancel lever which is rotatably engaged with each of the first cancel lever and the housing so as to rotate in the same direction as a direction of rotation of the first cancel lever in interlock with the rotation of the first cancel lever, wherein the second cancel lever is engaged with and mounted to the holder such that a direction of rotation of the second cancel lever is opposite to that of the holder, and wherein a center of rotation of the second cancel lever with respect to the housing is made displaceable within a predetermined range from a neutral position and the center of rotation displaced is made automatically restorable to the neutral position, wherein the center of rotation of the second cancel lever is one of a protrusion shaft and an elongated hole; the one of the protrusion shaft and the elongated hole is inserted into the other of an elongated hole and a protrusion shaft provided in a bottom plate of the housing, and is caught between both ends of a spring mounted to one of the bottom plate and the second cancel lever such that the both ends are exposed in the elongated hole to hold the protrusion shaft at a central position of the elongated hole, wherein the operating lever is caused to be automatically restored from an operating position to the neutral position in interlock with rotating operation of the first and second cancel levers in such a state, and wherein when an excess load for preventing automatic restoration from the operating position to the neutral position is applied to the operating lever, the protrusion shaft is moved from the central position of the elongated hole to the end position against a resilient force of the spring, whereby the first and second cancel levers are allowed to rotate.