Buckles – buttons – clasps – etc. – Separable-fastener or required component thereof – Including member having distinct formations and mating...
Reexamination Certificate
2001-06-04
2003-07-08
Brittain, James R. (Department: 3677)
Buckles, buttons, clasps, etc.
Separable-fastener or required component thereof
Including member having distinct formations and mating...
C024S633000
Reexamination Certificate
active
06588077
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a seat belt buckle used for a safety belt of an automobile or aircraft, and particularly to seat belt buckle in which a so-called measure to counter reverse G is taken.
2. Description of the Related Art
Generally, the above-described type of seat belt buckle is disclosed in, for example, Japanese Patent Application Laid-Open (JP-A) Nos. 60-18102, 60-75004, and 60-75005. In these buckles disclosed therein, a tongue plate is latched with the buckle such that a latch member of the buckle is engaged with a latch engaging hole of the tongue plate by inserting, into a buckle main body, an end of the tongue plate through which a seat belt (webbing) is inserted to pass. Further, the latched state is locked by a locking member and coming-off (ejection) of the tongue plate from the buckle main body is prevented.
When the locking state of the latch is cancelled by a pressing operation of a release button, latch engagement is cancelled and the tongue plate is made to come off from the buckle main body.
The above-described type of seat belt buckle is structured in such a manner that after the tongue plate is once inserted into the buckle main body completely to a lock position and locked, even if an impact is applied to the buckle, the tongue plate can be reliably held in a locked state without a latched and locked state of the tongue plate being cancelled. For example, the latch is constantly spring-urged (pressed) by a spring member toward the lock position, and the release button is returned to an original position. The release button for releasing the latched and locked state is structured so as to be able to be pressed by a small force.
Recently, safety devices have been proposed, wherein at the time of accidents such as a vehicle colliding with another vehicle or an obstacle, the buckle itself by which the tongue plate is locked, is instantaneously pulled due to instantaneous force such as explosion pressure of gunpowder and looseness of the seat belt is removed into a state of strain, thereby preventing various troubles caused by looseness of the seat belt.
However, when the buckle itself by which the tongue plate is locked is thus instantaneously pulled, so-called reverse G occurs in the buckle. Therefore, in a conventional buckle, even when the release button is not pressed, there may be a risk of the tongue plate being made to come off due to the locked state by the latch being cancelled. In other words, when the buckle itself is instantaneously and strongly pulled in a direction in which the seat belt is tensed, at the time of that the seat belt is tensed to the utmost, pulling of the buckle itself, that is, a case of a buckle main body is forcedly and rapidly stopped. Therefore, an inertia force corresponding to the total mass of the release button, locking mechanism, and the like which are accommodated within the case of the buckle main body in a state of being freely pressed, acts on the release button, locking mechanism and the like in a direction in which the lock state is released. As a result, there is a problem that the lock state may be forcedly cancelled and the tongue plate may come off form the buckle main body.
Accordingly, in order to prevent the tongue plate from coming off, in the conventional seat belt buckle, a method has been provided, wherein a spring force of the spring, which constantly urges the latch to a lock position by pressing, is increased. However, in this case, the spring becomes larger in size, and pressing force, that is, release force of the release button for releasing the locking state of the latch against spring force of the spring, may be increased.
SUMMARY OF THE INVENTION
In view of the above-described circumstances, an object of the present invention is to provide a seat belt buckle which can prevent coming-off of a tongue plate caused by so-called reverse G without increasing release force for canceling a lock state.
A first aspect of the present invention is a seat belt buckle comprising: a base including an insertion path in or from which a tongue plate having an engagement hole is inserted or removed, a pair of upright side walls, each of the side walls disposed at respective sides of the insertion path, and an engagement hole; a latch including latch lug portions supported swingably by supporting portions formed in the side walls of the base, and a latch swinging end portion swinging between a latch position at which, when the tongue plate is inserted to a latch position of the insertion path, the latch swinging end portion engagingly inserted into both of the engagement hole of the tongue plate and the engagement hole of the base so as to latch the tongue plate to the base, and a latch release position at which a latched state is released; a lock member including lug portions inserted swingably into supporting holes formed in the side walls of the base, a lock swinging end portion swinging between a lock position at which, at the time of the latched state, the lock swinging end portion latches (abuts) the latch swinging end portion in a state in which the latch swinging end portion is pressed toward both of the engagement hole of the tongue plate and the engagement hole of the base while the latch swinging end portion is pressed in a direction in which the tongue plate is inserted, thereby locking the latched state, and a lock release position at which a locked state is released; a lock sliding portion swinging together with the lock swinging end, and during swinging, sliding on the latch swinging end; a lock operation end portion which is located at the side opposite to the lock swinging end portion with respect to the lug portions interposed therebetween, and by which, when the lock operation end portion is pressed in the direction in which the tongue plate is inserted at the time of locking, the lock swinging end portion is made to swing to the lock release position, thereby releasing the lock state, and a weight portion by which a center of gravity of the lock member is made more eccentric to the lock swinging end portion than the lug portions; a latch spring elastically pressing, at the time of locking, the lock swinging end portion of the lock member substantially in the direction in which the tongue plate is inserted, to maintain the locked state; a release button including sliding portions mounted in elongated holes formed in the side walls of the base in a slidable manner in directions in and from which the tongue plate is inserted and removed, and a button which, when pressed against spring force of the latch spring in the direction in which the tongue plate is inserted, presses the lock operation end portion of the lock member in the direction in which the tongue plate is inserted, and causes the lock swinging end portion to swing in the direction from which the tongue plate is removed, thereby releasing the locked state; and an ejector which, when pressed by the tongue plate to a latch position, guides to fit the latch swinging end portion into the engagement hole of the tongue plate and the engagement hole of the base to allow latching and locking, and which, when the locked state is released by pressing the release button, presses the latch swinging end portion to the latch release position to release the latched state and removes the tongue plate from the insertion path of the base.
According to the above-described aspect of the present invention, the lock swinging end of the lock member presses to lock the latch swinging end of the latch for latching the tongue plate toward the engagement hole while pressing the same (from the front side (i.e., upstream side) to the rear side (i.e., downstream side)) in the direction in which the tongue plate is inserted. Therefore, when so-called reverse G occurs, that is, when an inertia force is generated due to rapid stopping of instantaneous pulling of the base, the inertia force acts on the lock swinging end (from the front side to the rear side) in the direction in which the tongue plate is
Katsuyama Soichi
Mori Shinji
Muromachi Tetsushi
Brittain James R.
Cole Thomas W.
Kabushiki Kaisha Tokai-Rika-Denki -Seisakusho
Nixon & Peabody LLP
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