PNEUMATIC READING SYSTEM FOR DOCUMENT CARDS

• Main Authors: LAGERGREN R,US, LENTZ R,US, SCHAFFER R,US, REIDENBACH J,US, JENSEN D,US
• Format: Patent
• Language: English
• Published: 01.01.1974
• Subjects: BASIC ELECTRIC ELEMENTS; CALCULATING; COMPUTING; COUNTING; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; HANDLING RECORD CARRIERS; PHYSICS; PRESENTATION OF DATA; RECOGNITION OF DATA; RECORD CARRIERS; SEMICONDUCTOR DEVICES

A document card reading system comprising a pneumatic switch assembly located opposite an air plenum and between which perforated document cards are passed. The plenum and switch assembly have aligned air discharge and reception ports between which jetted air flows when not blocked by a document card, and each of the reception ports is connected with a circular portion of a flexible film carrying a helical copper cladding contact portion. A contact board is disposed above the helical contact portions, and the board has cooperating contact portions of copper cladding each of which is provided with a series of slots so that the helical contact portions may in effect make edge to edge contact with the contact portions on the contact board. The helical contact portions and the contact portions on the board are sealed with respect to atmosphere by means of diaphragms of flexible film carried by a back plate located above the contact board, with small openings being provided through the contact board to provide communication between the flexible film carrying the helical contact portions and the diaphragms. A pump, such as a positive displacement pump, provides air under pressure to the plenum. Longitudinal grooves are provided in the facing surfaces of the switch assembly and plenum in communication respectively with the ports therein to prevent crosstalk or unwarranted application of pressure to any of the ports in the switch assembly not in alignment with an aperture in the document card.