US3321591A - Punched card reader - Google Patents

Description

May 23, 1967 Filed April 5, 1965 N. R. TIMARES PUNCHED CARD READER 2 Sheets-Sheet 1 oo o 000 0000 INVENTOR NORMA/V R. 7'/MA/?5 BY QM? m A Tron/v5) y 23, 1967 I N. R. TIMARES 3,321,591

PUNCHED CARD READER Filed April 5, 1965 2 Sheets-Sheet 2 i 5- //vl /vr0/e NORMAN R, 77MAREI A FOE/V5) United States Patent 3,3215% PUNCHED CARD READER Norman R. Timares, lLos Aug-tales, Calif, assignor to FMA, Inc., Los Angeles, Calif. Filed Apr. 5, 1965, Ser. No. 445,385 4 Claims. (Cl. 200-46) The present invention relates to improved punched card reader apparatus. In particular, the present invention is an improvement of the apparatus disclosed in Patent No. 3,144,525, issued to George S. Penn and Robert F. Kiddle on Aug. 11, 1964 and entitled Punched Card Reader.

With respect to said patent, when a card through which a predetermined pattern of holes has been punched is inserted in the apparatus described therein, connector pins pass through the card whereat the holes are located and, on the other side of the card, make electrical contact in such a manner as to produce an output pattern of voltages that corresponds to the pattern of punched holes on the card. The essence of that invention lies in the fact that on one end of the connector pins means are used that insure a uniform pressure on the pins, and on their other end means are employed that insure a uniform electrical contact for them. In particular, in an embodiment of the invention, a rubber-type pad is used to provide the spring action for the pins, and a single metal plate is employed for making the necessary electrical contact with them. Thus, by means of this earlier invention, the individual spring and metal sleeve elements so common in the prior art were eliminated and so were the attendant limitations.

However, although the punched card reader apparatus disclosed in Patent 3,144,525 was a marked improvement over other such devices found in the prior art, the user of this apparatus nevertheless encountered a rather troublesome problem in that, with continued use, lint, dust, and other foreign elements and impurities would become lodged between the plate and the connector pins so that poor electrical contact would be made between them, with the resultant etfect that the output voltages, if obtained at all, would be of relatively poor quality. This, obviously,

could only produce poor or erroneous results in whatever system such apparatus was being used.

The present invention improves over this earlier punched card reader apparatus by insuring good electrical contact between the plate and the pins at all times, irrespective of the length of the period of use. More specifically, in accordance with the concept of the present invention, this is done or achieved by insuring that each connector pin contacts the metal plate at least at two points and, furthermore, that a certain wiper action will take place between these two parts before relative motion between them terminates. Although the subject invention may be constructed in any one of several ways, in a preferred embodiment of it a series of grooves are incorporated in the plate structure, the grooves preferably extending across the full length of the plate and being shaped in such a manner that as the connector pins move through the holes of a punched card, they respectively come into contact with and wipe against one wall of the grooves, and then the other groove wall, and finally come to rest in firm mechanical and electrical contact with both walls. It is thus seen that by means of this technique, the aforementioned problems are eliminated.

The .novel features which are believed to be characteristic of the invention, both as to its organization and mode of operation, together with further advantages thereof, will be better understood from the following description considered in connection with the accompanying drawings in which an embodiment of the invention is illustrated by way of example. It is to be expressly understood, however, that the drawing is for the purpose of illustration and description only, and is not intended as a definition of the limits of the invention.

FIGURE 1 shows a card through which a pattern of holes has been punched;

FIGURE 2 presents a crosssectional view of a punched card reader apparatus according to the present invention;

FIGURE 3 is a top view of the contact plate for the purpose of illustrating the several grooves therein;

FIGURE 4 is an enlarged view of the tip of connector pin and its associated grooves in the contact plate, and illustrates the relationship therebetween as the former moves into the latter; and

FIGURE 5 is an enlarged view of the tip of a connector pin after it has come to rest in its associated groove in the contact plate.

Reference is made first to the punched card shown in FIG. 1, the card itself being designated 10, and the holes thercthrough being designated 11. The pattern in which holes 11 are arranged is in accordance with a predetermined code, while the size of and the spacing between adjacent holes respectively correspond to the thickness or diameter of the connector pins and the spacings between them. In the particular card being shown, the holes are arranged in columns and rows, and the discussion of the punched card reader apparatus that follows will be with this arrangement in mind.

In FIG. 2, the card reader is shown to include a metal contact plate 12 mounted on an insulative board 13, the plate and board combination, in turn, being fixedly mounted on a base 14 which may or may not be metal and which constitutes a part of the housing structure for the card reader. As is shown in the figure, contact plate 12 includes a plurality of grooves 12a with convexly curved side walls formed in its top surface, there being as many of these grooves as rows of connector pins, as will be more fully explained later.

Also mounted on base 14 and of the same thickness as the plate 12 and board 13 combination is a plate or board 15, board 15 being mounted on base 14 in such a manner that it overhangs the base in a cantilevered fashion. Fixedly mounted above contact plate 12 and board 15 and in face-to-face relationship with them is still another plate or board member 16 made of an insulative material. The spacing between plate 12 and board 15 on theone hand and member 16 on the other hand is only enough to permit a punched or perforated card 10 to be inserted in the space therebetween, and it is for this reason that element 15 is cantilevered, namely, to facilitate the insertion of a card. A punched card 10 already inserted in the space provided for it is shown in the figure. Finally, member 16 has as many holes or channels through it as there are connector pins, the purpose of these channels, which are designated 17, being to protect and properly direct the movement of the pins into contact with the grooves in plate 12, as will be seen later. Accordingly, upon insertion of a card 10, holes or channels 17 come into registration with or, stated differently, respectively become positioned over all the points on the card whereat perforation-s or holes may possibly be located. Thus, a channel 17 is positioned over each spot on card 10 whereat a hole may be punched or is punched through it.

Also included in the card reader is a housing block 18 whose walls may or may not be of metal and which is movably positioned above board member 16. Inside housing block 18 and held by the walls thereof is a pinhousing block 26 that faces board member 16. Pinhousing block 20 is made of an insulative material and has a plurality of holes or channels 21 through it which respectively are in registration with holes or channels 17 therebeneath. As may be expected, the connector pins, generally designated 22, are mounted in the extend through hole-s 21, with the result that there are as many of these holes 21 as there are connector pins 22 and holes 17 through board 16. Finally, inside housing block 18 and cemented or otherwise mounted to the surface of the top wall thereof is a rubber-type pad 23 whose function it is to apply a spring-type force to the connector pins with a minimum of cross-talk between them, specifically, a minimum between those pins that pass through punched card it and those that do not. In turn, this is done by minimizing the differential travel of the pins between their two possible positions.

With respect to pins 22, they respectively include a thin metal rod 22a. and a shoulder or flange element 221') that abuts against the top of pin-housing block 20 when the bottom portion of .rod 22a has passed through a hole in card and come into contact with plate 12. Thus, ele- 'ments 22b respectively help to limit the downward movement of the connector pins, and they are so fabricated and positioned or located on rods 22a as to control this downward travel within very fine tolerances. Rods 22a are necessarily made of metal, whereas elements 221) may or may not 'be made of metal. As previously indicated, rods 22:: are slidably mounted in holes 21, the extremities of the pins on one side extending through channels 17 until the tips thereof are contiguous to contact plate 12. The extremities of the pins on the other sides extend upwards until they come into pressure contact with pad 23. Pins 22 are rounded at their upper tips so as to reduce the possibility of damage to the pad as much as possible, and they are tapered at their bottom tips so that they can make good electrical contact with plate 12 when they are allowed to do so, as will be explained below.

Housing block 18 may be moved slightly up or down, that is, away from or toward board member 16, the distance through which it can be moved being only enough to raise pins 22 so that a punched card 1t may easily be inserted in the space between contact plate 12 and member 16. Housing block 18 may be raised and lowered in any one of a number of ways, all of them being well known in the mechanical arts. Thus, merely by way of example, a simple lever apparatus may be coupled to the housing block 18 to manually raise or lower very much in the same mannerias a drill bit is raised or lowered in a drill press. Since the manner in which the housing block is raised and lowered involves a state-ofthe-art mechanical arrangement, it is not shown in the figure for the sake of expediency. Also not shown in the figure is a source of either positive or negative potential connected to contact plate 12. Finally, in order to detect or determine whether or not potentials exist in any one or more of pins 22, leads or wires 24 are respectively electrically connected to the pins, the leads or wires being coupled to external circuitry which does not form a part of this invention.

Returning briefly to contact plate 12 and to grooves 12a formed therein, these groove extend for the full length of the plate, as is clearly shown in the view of FIG. 3, and they are tapered and rounded convexly along their sides in the manner shown in FIG. 4 so as to provide the desired wiping action and to form dual points of contact with the pins. More specifically, the shape of the grooves is detenrnined by tolerance allowances, and must meet at least three conditions, namely:

(1) Contact between a pin and groove must be dual, that is to say, must occur at least at two points, as previously mentioned;

(2) The shape of the grooves must allow a proper pressure angle for extreme pin positions within the allowed tolerances so that the pins will be directed toward the center of the grooves or slots; and

(3) With respect to a feature that was previously explained, namely, that of cross-talk, the groove shape must be such as to allow a minimum of cross-talk between those pins that have passed through the holes in the punched card and entered grooves 12a and those that have been prevented from doing so. As was previously mentioned, this is achieved by minimizing the differential travel of the pins in these two positions, and a proper shaping of the grooves will contribute toward a minimization of this differential travel.

in operation, prior to the time a card 10 is placed in the card reader, housing block 18 is in its raised posi; tion so that the space into which the car-d is inserted is free of pins 22 which might otherwise interfere with the proper insertion of the card. However, once a punched card is inserted in the space provided between elements 12 and 16, the housing block is then lowered, and when this is done, the tips of pins 22 are brought into contact with the card which, in consequence thereof, exerts an upward or backward push on the pins. More specifically, those pins that are in registration with the holes punched through the card will be urged by rubber pads 23 to pass through the holes and make contact with plate 12, it being those pins that do not pass through the card that are pushed back by it.

It will be noticed from FIG. 2 that the pins that do not encounter holes in the card are actually moved upwards slightly as indicated by the slight spacings between tlanges 22b on these pins and the top surface of pin-housing block 2%. This slight upward displacement of the pins is taken up by the elastic pad which indents or becomes deformed slightly at the points whereat these pins press against the pad. As for the pins in contact with plate 12, these pins now have the same potential on them as is found on plate 12, the signals thereby produced being fed elsewhere by means of leads 24. To remove the card, housing is raised, thereby also raising the pins and allowing room for the card to be withdrawn. It will be recognized that upon raising the housing block, those of pins 22 that were previously moved upward by card It) will now be moved downward the same amount by rubber pad 24-. As a result, the bottom tips of the pins are once again in the same plane and ready for the next punched card to be inserted. It is thus seen that by using a rubber-type pad 23, the desired forces can be maintained on the pins and with a minimum of cross-talk between them.

Considering the manner in which contact is made between plate 12 and pins 22 in greater detail, reference is once again made to PEG. 4 wherein, according to the allowed tolerances of the apparatus, rod 22a of the pin illustrated therein is shown in an extreme unaligned position with respect to its associated groove 12a. As a resuit, as pin rod 22a moves toward groove 12a, it first strikes one side or wall of the groove, and because of the walls curvature and taper, the pin rod is deflected toward the grooves opposite side or wall. However, most importantly, before it is deflected, the rod, because of its downward motion, wipes or scrapes the side or wall of the groove to thereby make possible the desired goodquality electrical contact between them. Following the above-said deflection of the pin rod, it comes into contact with the opposite side or wall of the groove where the same wiping or scraping action takes place as the pin continues to move into the groove, so that good-quality electrical contact is thereby also obtained on this side. When rod 22a has completed its travel into groove 12a, it will be lodged in the groove as shown in FIG. 5, wherein is also shown the dual points of contact, designated 25a and 25b, between the rod and the walls of the groove. It can thus be seen that by using a metal plate 12 with grooves 12a therein of the kind described, the same potential within very accurate limits is applied to the pins, thereby reducing the possibility of errors in the output signals fed over lines 24-.

Although a particular arrangement of the invention has been illustrated and described above, it is not intended that the invention be limited thereto. Accordingly, the invention should be considered to include any and all modifications, alterations or equivalent arrangements falling within the scope of the annexed claims.

Having thus described the invention, what is claimed is:

1. A punched card reader comprising: a flat, rigid electrically conductive plate having long, straight grooves therein with convexly curved side walls; a plurality of electrically conductive pins perpendicularly positioned over said plate in approximate registration with the grooves thereof, said pins each being tapered at the tip adjacent said plate so as to become aligned with and make contact with both walls of said grooves when the tips thereof are moved therein; means for supporting said pins so they are axially movable and have a small lateral play suflicient to permit contact with both walls of said grooves; and means for selectively applying a pressure to said pins to move them axially into said grooves, said means including a resilient pad mounted over said pins and in contact therewith for directly applying said pressure.

2. A punched card reader comprising: a plurality of electrically conductive pins, the tip of each pin being tapered to form truncated conical sections; a flat, rigid electrically conductive plate having longitudinal grooves therein in approximate registration with the pins, said grooves having convexly curved walls so as to deflect the tips of said pins toward the centers of the grooves upon axial movement of the pins toward the grooves and to provide two points of electrical contact between a pin and its groove; means for holding each pin so it is axially movable and has a small lateral play sufiicient to permit contact with two points of its groove; and means for selectively moving said pins axially into said grooves.

3. A punched card reader comprising: a flat, rigid electrically conductive plate having longitudinal grooves therein with convexly curved side walls, said grooves being substantially parallel to each other and extending for the full length of said plate; a housing structure positioned over said plate and adapted to be selectively moved toward and away from said plate; a resilient pad mounted in said housing structure and parallel to said plate; and a predetermined number of electrically conductive pins slid,- ably mounted in said housing structure in a position that is perpendicular to both said pad and said plate with lateral play sufficient to cause contact with both sidewalls of the grooves upon sliding the pins toward the plate, said pins being arranged in substantially parallel rows that are in approximate registration with said grooves, said pins being in pressure contact with said pad at one end and being contiguous to said plate and tapered at the other end thereof.

4. A punched card reader comprising: a base structure that includes a flat, rigid electrically conductive plate in which longitudinal convexly curved grooves are formed, said grooves being parallel to one another and extending the length of the plate, a housing structure positioned over said plate, such structure including an electrically insulative wall facing said plate and having a plurality of connector-pin holes therethrough arranged in rows that are respectively in approximate registration with said grooves, an electrically conductive connector pin slidably positioned in and extending through each of said holes toward said metal plate, said connector pins each being tapered at the end facing toward said metal plate; and a rubber-like pad mounted over said pins and in contact therewith for applying a forward pressure thereto, said pins being held with sufficient lateral play that, in response to said pressure, they are forced through the holes in the punched card and into said grooves wherein they respectively make contact with both walls of said grooves; and means for spacing said base and housing structures to permit a punched card to be inserted therebetween and thereafter removed.

References Cited by the Examiner UNITED STATES PATENTS 233,968 11/1880 Bergman 317-112 648,432 5/1900 Prentiss 200-166 2,389,429 11/ 1945 Griffith. 2,924,685 2/1960 Burch 200-166 3,144,525 8/1964 Fenn et al 200-46 3,168,635 2/1965 Gebhart 200-166 BERNARD A. GILHEANY, Primary Examiner.

T. MACBLAIN, H. E. SPRINGBORN,

Assistant Examiners.

Claims (1)

1. A PUNCHED CARD READER COMPRISING: A FLAT, RIGID ELECTRICALLY CONDUCTIVE PLATE HAVING LONG, STRAIGHT GROOVES THEREIN WITH CONVEXLY CURVED SIDE WALLS; A PLURALITY OF ELECTRICALLY CONDUCTIVE PINS PERPENDICULARLY POSITIONED OVER SAID PLATE IN APPROXIMATE REGISTRATION WITH THE GROOVES THEREOF, SAID PINS EACH BEING TAPERED AT THE TIP ADJACENT SAID PLATE SO AS TO BECOME ALIGNED WITH AND MAKE CONTACT WITH BOTH WALLS OF SAID GROOVES WHEN THE TIPS THEREOF ARE MOVED THEREIN; MEANS FOR SUPPORTING SAID PINS SO THEY ARE AXIALLY MOVABLE AND HAVE A SMALL LATERAL PLAY SUFFICIENT TO PERMIT CONTACT WITH BOTH WALLS OF SAID GROOVES; AND MEANS FOR SELECTIVELY APPLYING A PRESSURE TO SAID PINS TO MOVE THEM AXIALLY INTO SAID GROOVES, SAID MEANS INCLUDING A RESILIENT PAD MOUNTED OVER SAID PINS AND IN CONTACT THEREWITH FOR DIRECTLY APPLYING SAID PRESSURE.

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