Patent ID: 8813322

Claim:
A restraint system for car safety seats, comprising: a pair of upper belts; a lower belt having an end; a pair of tongue-like coupling elements, each of the tongue-like coupling elements being connected to a respective one of the upper belts; a buckle comprising: a case adapted to be connected to a lower belt of the restraint system; a coupling mechanism arranged to releasably engage the tongue-like coupling elements; and an indicator device to indicate to a user a correct tensioning of the belt; the indicator device comprising: at least one indicator element having a visual symbol adapted to be seen by the user through at least one opening provided in the case of the buckle, said indicator element being received in the case of the buckle to be movable between a first end-of-travel position, corresponding to a condition of loose belts, in which said visual symbol is not visible by the user, and a second end-of-travel position, corresponding to a condition of correctly tensioned belts, in which said visual symbol is visible by the user through said at least one opening, said indicator element being resiliently urged towards either of said first and second end-of-travel positions, at least one locking element received in the case of the buckle to be movable relative to the case of the buckle, said at least one locking element being connected either directly or indirectly to an end of the lower belt of the restraint system to move with said end of the lower belt relative to the case of the buckle when the lower belt is tensioned; and at least one spring interposed between the case of the buckle and said at least one locking element to be resiliently deformed as a result of application of a tension force on the lower belt of the restraint system, to bring about a corresponding movement of said at least one locking element; wherein said at least one locking element is configured to cooperate with said at least one indicator element in such a manner that when said at least one indicator element is in said second end-of-travel position once the correct tension in the lower belt is reached, the at least one indicator element is locked in the second end-of-travel position by said at least one locking element.