Lock mechanism of electric connection box

摘要

A lock mechanism includes: a lock arm provided in a cantilever manner on an inner wall of a part compartment of a box body of an electric connection box; and a lock projection provided to the lock arm on its surface facing a part housed in the part compartment. The lock arm can be divided in a longitudinal direction into: a base end region fixed to the inner wall; upper end region located in the free end which interferes with the part and receives a pressing force for unlocking operation; and a middle region located within a predetermined distance range between the base and upper end region. The flexural rigidity of the base and upper end region is set larger than that of the middle region by providing ribs on the base and upper end region and providing no ribs on the middle region.

主权项

1. A lock mechanism, comprising:
a box body including a part compartment for housing a part; a lock arm provided on an inner wall of the part compartment in a cantilever manner so as to protrude from the inner wall, the lock arm being bent due to an interference between the lock arm and the part when the part is put into the part compartment; and a lock projection provided to a surface of the lock arm facing the part housed in the part compartment, the lock projection being engaged with the part due to a returning action of the lock arm to an original state after the part has passed through the lock projection interfering with the lock projection, wherein the lock arm comprises, in a longitudinal direction of the lock arm:
a base end region located in a base end of the lock arm fixed to the inner wall of the part compartment;an upper end region located in a free end which interferes with the part and receives a pressing force applied for unlocking operation; anda middle region located within a predetermined distance range between the base end region and the upper end region, wherein the base end region and the upper end region each includes at least one rib that provides the base end region and the upper end region a flexural rigidity larger than a flexural rigidity of the middle region, wherein each of the at least one rib included in the base end region and the at least one rib included in the upper end region extends in a longitudinal direction of the lock arm and has a projection height decreasing as each of the ribs approaches the middle region, and wherein the thickness of the cross-section of the middle region of the lock arm is substantially narrower than the thickness of the cross-section of the base end region and the upper end region, wherein the locking arm projects from a perimeter of the box body, and wherein the projection height of the at least one rib included in the base end region decreases as the at least one rib included in the base end region projects from the perimeter of the box body towards the middle region.