New England woman who invented the snap button which you can find anywhere now. It was first a collar-button with a spring cap attached to the outer side. Any of you who wear modern waterproofs know the button that simply pushes together, and when you unbutton it you simply pull it apart. That is the button to which I refer, and which she invented

found your text, and from the continuing sentences, I think you can simply describe it as "Druckknopf"

ich stimme zu, dass es um Druckknöpfe geht (also snap button); aber da du nach dem spring cap fragtest: das wäre dann die Kappe und da gibt es eine spezielle Form, die das Öffnen erleichtert durch leichten Widerstand ("Feder")

siehe Quelle