Buckle of vehicle safety belts, particularly vehicle safety belts for children

A seat belt buckle comprising a frame;

• a latch member pivotally mounted to the frame;
• a casing enclosing a substantial part of the frame and forming an insert opening;
• a tongue member insertable through said opening;
• a first pressure spring biasing the latch member to a position of engagement with said tongue member when inserted through said opening;
• a finger-access opening formed by said casing;
• and a second elongated resilient spring member separate and detached from the latch member and disposed in the casing and clamped between the frame and the casing in a manner to be bendable towards the latch member but to resiliently resist such bending, and accessible for finger pressure through said opening to be resiliently bent against its spring force transversely towards the latch member, the latch member being interposed between the first pressure spring member and the second elongated resilient spring;
• the second elongated resilient spring member operating the latch member to a disengaged position only against the combined spring force provided by said pressure spring and said elongated resilient spring member, for releasing the tongue member.