Buckle for restraint belts, particularly for car safety seats for children

A buckle for a fastening device for three-branch restraint belts for car safety seats for children, comprising an inner body adapted to receive stem portions, provided with coupling teeth, of a pair of tongues to be attached to two of the three belt branches, and a snap coupling mechanism adapted to releasably connect the tongues to the inner body;

• wherein
• the inner body having a through opening through which the stem portions of the tongues are insertable along a direction of insertion;
• the snap coupling mechanism comprises:
• a locking element supported by the inner body to be pivotable about a first pivot axis perpendicular to the direction of insertion between a locked position, in which the locking element engages the tongues to keep the tongues restrained in the inner body, and an unlock position, in which the locking element disengages the tongues to make the tongues free to be ejected from or pulled out of the inner body;
• a release button movable by a user along a direction perpendicular to the direction of insertion and to the first pivot axis between a raised position and a lowered position corresponding to the locked position and to the unlocked position of the locking element, respectively;
• a first resilient member operatively associated with the release button to apply the release button a resilient force tending to keep the release button in the raised position;
• at least one slider mounted in the inner body to be slidable parallel to the direction of insertion to oppose the insertion of the tongues into the inner body;
• and
• a second resilient member operatively associated to said at least one slider to apply on said at least one slider a resilient force directed in the opposite direction with respect to the direction of insertion of the tongues into the inner body and in the direction of ejection of the tongues from the inner body;
• wherein at least one slider is configured to come, under the action of said second resilient member, between the inner body and the locking element, when the locking element is moved into the unledock position to prevent the locking element from moving from the unlocked position to the lock position, and
• wherein the release button and the locking element are connected to each other in such a manner that when the release button is pressed and then moved into the lowered position, the locking element moves into the unlocked position, and wherein when the release button is released, and gets back into the raised position as a result of the resilient action applied on the release button by said first resilient member, the locking element is pulled by the release button to the locked position.