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US 4,393,302 AGranted
Apparatus and method for reading punched cards
AssigneeAdvanced Card Systems, Ltd.
InventorRolf L. Hofmann
Life of this patent
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Abstract
The present invention relates to an apparatus and a method for reading punched cards and, more particularly, to such apparatus, and method for reading gravity-fed punched cards. This apparatus comprises a reference perforation sensor located upstream of the hole sensors so as to sense the duration of the passage of a reference perofaration cut out in a card, before any hole position faces the set of hole sensors.
Claims13
A method for reading punched cards having holes arranged in rows and columns, comprising the steps of:
- (a) gravity feeding a card to a reading station, along a path parallel to the rows of perforations of the card,
- (b) measuring the period of time .DELTA.t.sub.o between the passage of the leading edge of the card and the passage of a particular hole, at a sensing position in the reading station,
- (c) measuring the period of time .DELTA.t.sub.n between the passages of the leading and trailing edges, respectively, of said hole and,
- (d) computing ratio .DELTA.t.sub.o /.DELTA.t.sub.n for determining the position of the column comprising said hole.
1 more element
Apparatus for reading cards having holes arranged in r rows and c columns, comprising:
- (a) means for gravity feeding a card along a path parallel to the rows of hole positions,
- (b) a reading station having a set of r hole sensors aligned transversely to the feed path so that each sensor is associated with one of the r rows.
- (c) a card presence sensor adapted to sense the presence of a card in the reading station,
- (d) first means for measuring the period of time .DELTA.t.sub.o elapsed from the passage of the leading edge of a card in front of the card sensor to the passage of a particular hole of the card,
- (e) second means for measuring the duration .DELTA.t.sub.n of the passage of that hole in front of the associated hole sensor, and
- (f) means for computing ratio .DELTA.t.sub.o /.DELTA.t.sub.n so as to derive from that ratio the column position of the sensed hole.
3 more elements
Dependencies are inferred from the claim text.