Buckle with noise prevention mechanism

A buckle comprising:

• a base made of metal and having a U-shaped section formed of first side walls and a bottom, said first side walls having guide portions on inner surfaces thereof for guiding a tongue when the tongue is inserted therein;
• a latch mechanism disposed on the base for latching the tongue to the buckle;
• a cover made of resin for housing the base and having a lower cover for defining a tongue-insertion opening, said lower cover having an inlet portion for defining a part of the tongue-insertion opening, said inlet portion projecting upwardly for a predetermined distance into a path for the tongue from a surface of the bottom of the base facing the path for the tongue;
• and
• an operational member made of resin for releasing an engagement of the latch member with the tongue, said operation member being disposed in the cover to define the tongue-insertion opening together with the inlet portion and having two second side walls as an opening forming portion defining a part of the tongue-insertion opening, said second side walls being located between the first side walls adjacent thereto and projecting for a predetermined distance into the path for the tongue from lower surfaces of the guide portions facing the path so that when the tongue is inserted into buckle, the tongue touches at least one of the inlet portion of the cover and the second side walls of the operational member without touching the bottom of the base and the guide portions to prevent a noise in inserting the tongue.