Encoder for a teaching machine

Claim 1

An encoding device for a teaching machine having a graphic answer input, said device being of the type wherein electrical interconnection between a plurality of leads is selected under the control of a punched card, said device comprising: a contact bearing board of insulation material having a first plurality of electrical contacts disposed thereon in a predetermined pattern with each contact having a different lead of a first set of leads connected thereto; an encoder-board of insulation material disposed therebelow and in substantial registry with said contact-bearing board and having a plurality of sockets therein arranged in said predetermined pattern, a second plurality of electrical contacts each of which is respectively disposed in one of said sockets and in coaxial relationship with a respective one of said first plurality of contacts, each said second plurality of contacts having a different lead of a second set of leads connected thereto; spring means disposed in said sockets for urging said second plurality of contacts toward said first plurality of contacts; and a replaceable card disposed between and in registry with said contact-bearing board and said encoderboard respectively, to insulate each of said contacts of said first plurality of contacts from each of said contacts of said second plurality of contacts, said card having predetermined holes disposed therethrough, whereby selective contacts of said second plurality of contacts are urged through said holes by said spring means to electrically engage with respective contacts of said first plurality of contacts so as to effect selective electrical interconnection between respective ones of said first and second sets of leads.