Patent ID: 7540260

Claim:
A spring operated squirrel proof bird feeder comprising: an inner housing telescopically and slidably surrounded by an outer housing; said inner housing in communication with a source of birdseed and having an opening in an inner housing side wall; said outer housing having an opening in an outer housing side wall, said outer housing being capable of substantially vertical movement between a first position at which said outer housing opening is in substantial alignment and communication with said inner housing opening so as to provide a through opening to provide access to the birdseed, and a second position at which said outer housing opening is in substantial misalignment and noncommunication with said inner housing opening so as to restrict access to the birdseed; and a compression spring operatively interconnecting said inner and outer housings such that transmission to said outer housing of a load heavier than a predetermined weight compresses said spring and moves said outer housing from said first position to said second position, and such that removal from said second housing of the load heavier than the predetermined weight uncompresses said spring and moves said outer housing from said second position to said first position; said inner and outer housings each configured to have complementary shaped opposed surfaces that mate with one another so as to resist twisting movement of the outer housing relative to said inner housing as said outer housing moves between said first and second positions so as to guide movement of the housings away from and toward each other in a substantially vertical direction, one of said inner and outer housings including an exterior surface having a plurality of tapered recesses therein, and the other of said inner and outer housings including a plurality of tapered projections forming an upper surface of said outer housing and complementary in shape to said tapered recesses, said tapered recesses and said tapered projections forming said opposed mating surfaces and being engaged with one another when said outer housing moves from said second position to said first position.