US Patent 7174859 Adjustable pet collar

An adjustable pet collar comprises a long chain and an adjuster. The adjuster is constructed by a upper cover and seat body, in which a slit is opened on the upper cover and a slanting channel is disposed on the seat body. The chain is placed in the channel, and a sliding groove in which one end thereof is closed perpendicular to the channel is disposed at one side of the channel, and a recess groove is disposed at another end thereof. An inserting pin seat is installed in the sliding groove, and an elastic element is installed between the inserting pin seat and the closed end of the sliding groove. Whereby, the size of the collar formed by the chain is adjusted by the inserting pin seat.