Tape Reader

Abstract

A tape reader is provided in which the feeding and reading pins are carried in a reciprocating frame moving substantially parallel to the tape so as to give a wiping motion to the associated electrical contacts. The pins are sawtooth-shaped and spring loaded so as to slide under the tape on a reverse stroke, the tape being retained by retaining pins.

Description

BACKGROUND OF THE INVENTION

This invention relates to devices for reading perforated tapes and the like and in particular to mechanically operated tape readers of the type wherein the punched holes motivate the sensors which in turn control electric contacts. It is a well-known fact that mechanical readers normally operate with small contact forces so as to ensure long life of the tape. Because of the small forces involved, previous designs have suffered from the accumulation of dirt on the contacts and consequent "stickiness" in operation of these contacts.

SUMMARY OF THE INVENTION

According to the present invention there is provided a reader for a perforated record medium, such as a tape or card, in which the feeding means comprises a reciprocable feed member carrying one or more permissive feed elements adapted to engage and feed the medium incrementally as the feed member moves in one direction and then to a slide relatively to the medium as the feed member moves in the opposite direction, the medium being meanwhile retained in its last fed position by one or more permissive locating elements.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the invention will now be described by way of example with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view to show one of the code-sensing elements and its associated switching mechanism,

FIG. 2 is an end view to show how the code-sensing and feed elements are mounted,

FIG. 3 is a perspective view to show the feed element, and

FIG. 4 is a perspective view of the complete reader.

DESCRIPTION OF PREFERRED EMBODIMENT

Referring to FIG. 1, each code-sensing assembly comprises two arms, a sensing arm 1 carrying a sawtooth pecker element 2, and a switching arm 3. These pivot on a common shaft 4, and are connected together by a tie rod 5. An abutment 6 on each arm just in front of the pecker 2 allows small independent motion of the arm 1 in a downward direction or of the arms 3 in an upward direction. This flexibility ensures the maintenance of even contact pressure at the contact end 7 of arm 3 but constrains them to move together when sensing. The contact end 7 moves between fixed contacts 8.

The code-sensing assembly is loaded to give the required upward pressure at the sensing pecker by means of a spring 9 acting in a downward direction via the balance beam assembly shown in more detail in FIG. 2. This balance beam assembly comprises a first set of three beams 10, 11 and 12 interconnecting the tie bars 5, and a second set of two beams 13 and 14 interconnecting the beams 10, 11 and 12. The appropriate number of code-sensing assemblies are built up on the shaft 4 as required to read the number of tape tracks. For example a five-track tape would have five assemblies.

The tape-feeding assembly is illustrated in FIG. 3 and is similar to the code-serving assembly shown in 1. The main difference is that the feeding arm 15 carries two sawtooth peckers 16, spaced one tape hole pitch apart. The peckers 16 on arm 15 engage the transport holes in the tape 17 and drive it forward. During the return stroke of the arm 15, the tape is held by an arm 18 which also carries two locating peckers 19 spaced one hole pitch apart and is loaded by a spring 20 in an upward direction for rotation on a pivot 21. The arm 15 is linked to a switching arm 22 by means of a tie bar 23 similar to tie bars 5 and similarly connected to the spring 9 by the balance beam assembly shown in FIG. 2. The contact end of arm 22 moves between fixed contacts 30 and 31. The arm 22 does not touch the upper contact 30 when there is tape in the reader. The contact 30 is provided in order to detect a "tape out" condition. The arm 22 will touch the lower contact 31 during the return stroke, provided the tape is held in position by the peckers 19 and the feed holes are not torn. In this way, an efficient check of tape feed can be achieved. They may also serve another purpose to be explained later.

Referring to FIG. 4, it will be seen that the code-sensing and tape-feeding assemblies by virtue of being pivoted on the common shaft 4 are carried in a feed member having side arms 24 attached to a magnet armature 25. The switching arms 3 and 22 pass through a guide plate 26.

When a magnet 27 is energized it draws the armature 25 towards itself, moving the sensors which have already set the switching arms to mark or space positions. These slide over their respective fixed contacts maintaining the sensed code combination.

When the armature has attained its fully energized position, the peckers 19 enter the feed holes and hold the tape. When the armature is deenergized and moves back to its stop 28 under the action of a return spring 29 the remaining peckers are cammed out of the tape by virtue of their sawtooth configuration and take up position under the next row of feed holes, thereby setting up the next code.

The contacts operated by the feeding peckers 16 may be used to inhibit reading when the armature is moving.

It is to be understood that the foregoing description of specific examples of this invention is made by way of example only and is not to be considered as a limitation on its scope.

Claims

I claim:

1. A reader for a perforated medium comprising:

a feed member reciprocating in a substantially straight line parallel to the feeding motion of the medium;

a plurality of spring loaded sensing assemblies, each assembly including a sensing arm having a sawtooth-shaped sensing element and a switching arm, said assemblies being pivotally mounted on a common shaft mounted in said feed member;

a spring loaded feed assembly including a feeding arm and an associated switching arm, said feeding arm including a sawtooth-shaped feed element, said feed arm and associated switching arm being pivotally mounted on said common shaft;

a locating element for retaining the medium in the last fed position during movement of the feed element out of engagement with holes in the medium; and

said switching arms and associated switching arm adapted to serve as moving electrical contacts making sliding contact with one or another of a respective pair of fixed contacts as the feed member reciprocates, whereby the contacts are self-cleaning.

2. A reader as claimed in claim 1 in which the feed member is attached to an armature of an electromagnet, such that it is moved against a return spring when the magnet is energized.

3. A reader as claimed in claim 2 in which the moving electric contact associated with the feed element is used to indicate a "tape out" condition and to indicate that the tape is actually moved during a feed cycle.

4. A reader as claimed in claim 2 in which the moving electric contact associated with the feed element is used to inhibit reading when the feed member is moving.

5. A reader as claimed in claim 1 in which the spring loading is in the medium-sensing direction by a single spring acting on one arm of each assembly through a balance beam arrangement.