US2806695A - Card feed station - Google Patents

Description

Sept; 17, 1957 K. R. CARLISLE CARD FEED STATION Filed Mrcn 1, 1955` EZ@- 3. l

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CARD FEED STATGN Kenneth Robert Cariisle, rfoi-rance, Calif., assigner to Hnghes Aircraft Company, Culver City, Saixf., a corporation of Delaware Application March 1, 1955, Serial No. 491,372

1 Claim. (Cl. 271-11) This invention relates to devices for feeding cards to a conveyor, and more particularly to a device for feeding punched cards or the like at a rapid rate to a fast-moving conveyor.

It is well known in the prior art to employ conveyors for processing documents, photographs, or cards in a continuous process. Such conveyors may utilize gravity, friction, or vacuum either for picking up a stationary card; or for retaining a moving card upon the conveyor.

The present invention relates specifically to a feed station for feeding cards to a high-speed conveyor of the type which employs a friction pickup. It is necessary in utilizing the present invention, in order to pick up and move one cardat a time from a stack of cards, that the coeicient of kinetic friction between a card to be moved and the surface or" the conveyor shall be greater than the coefficient of static friction between two of such cards.

In 'the prior art it is well known to employ a card feed station which utilizes moving mechanical parts for releasing each card individually, one at a time. Such devices provide very satisfactory operation, but their maximum operating rate is limited to a few hundred cards per minute. v

The invention is illustrated in conjunction with a system wherein a number of punched cards of the type used with business data processing equipment are to be transported from one location to another in a continuousprocess. A stack of cards to be processed is arranged horizontally in an input magazine from whence they are picked up by a first rotating drum, passed on to a second rotating drum, and then received in a horizontally arranged output magazine. The rst or pickup drum rotates at a high rate of speed about a vertical axis, and picks up the cards from the input magazine primarily through friction, but with partial assistance from a vacuum maintained within the drum. T he surface of the drum is perforated with holes or slots in order that the vacuum may produce a lower air pressure on the side of the card which is adjacent to the surface of the drum.

It is, therefore, an object of the invention to provide a device for feeding cards at a rapid rate to a rapidly moving conveyor.

Another object of the invention is to provide a device, having no moving parts, for feeding cards to a conveyor of the friction type which may be a rotating vacuum drum for retaining a card that has been picked up.

A further object of the invention is to provide a device for feeding at a rapid rate, a stack of cards which is arranged horizontally in an input magazine to the surface of a drum which is rotating rapidly about a vertical axis and which accomplishes the pickup of the cards primarily by friction and secondarily by means of a partial vacuum within the drum.

ri'he novel features which are believed to be characteristic of the invention, both as to its organization and vmethod of operation, together with further objects and advantages thereof, will be better understood from the 2,806,695 ?atented Sept. 17, 1957 following description considered in connection with the accompanying drawing 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.

Fig. 1 illustrates in schematic form a card transfer system wherein the card feed station of the present invention may be utilized;

Fig. 2 is an enlarged plan view of a card feed station in accordance with the present invention; and A Fig. 3 is a vertical cross section view of the card feed station taken on line 3 3 of Fig. 2.

Reference is now made to Fig. l wherein a card transfer system is illustrated in schematic form. An input magazine lil contains a stack of cards 11 which are kept in place by means of a pressure device indicated schematically by an arrow 12. A vacuum pickup drum 13 rotating in the direction indicated by the arrow is arranged to pick up the cards from the input magazine and to send them through a chute 14 to a reversing drum 15 which rotates in an opposite direction shown by the arrow. A vacuum pump 16 is utilized for maintaining a partial vacuum in each of the drums, and each drum surface has perforations or slots for holding the cards on the drum surface. An output magazine 17 is shown containing a stack of cards i3 which has already been transferred, the stack being maintained in position by another pressure device indicated by an arrow 19.

in the system of Fig. l the card feed station is indicated generally by means of an arrow 20, and a card stacking station adjacent to the output magazine is indicated generally by an arrow 21. For the purpose of the present invention, it is necessary to describe only the card feed station in greater detail, hence reference is made to Fig. 2 for that purpose.

In Fig. 2 there is shown an enlarged and plan view of the card feed station of the system of Fig. l. The pickup drum is again designated by the numeral i3 and the input magazine by the numeral iti. The stack of cards is designated generaly by the numeral 11, and the cards of the stack adjacent the drum are specifically identified by reference characters lia, 11b, 11e, and lid. The input magazine i@ is shown as including a lower retaining wall 30, a stationary end piece 3l, and an upper retaining wall 32. Between the end piece 3i and the upper retaining wall 32 there is provided an aperture through which the first card of the stack may be picked up by the revolving drum i3.

That portion of retaining wall 32 which is in nearest proximity to the revolving drum 13 will be referred to as the feed throat. Significant features of the feed throat include a curved guiding surface 33, a lirst vertex 34, and a second vertex 35. Vertex 34 is spaced from the surface of the drum by a distance which is equal to the thickness of from 2 to 5 cards. Vertex 35 is spaced from the surface of the drum by a distance which is more than the thickness of one card, but less than the thickness of two cards.

In operation, the revolving drum picks up the rst card such as lla by means of friction, and carries it around during the rotation of the drum, a clamping or holding action being obtained because of the partial vacuum the drum. The vacuum conveyor principle is well known and needs no further explanation here; for example, U. S. Patent No. 1,968,941, issued on August 7, 1934, to B. I. Hall et al., shows a series of evacuated drums used for transporting a set of papers from one position to another while various operations are performed thereon. In order for the card ila to be picked up by the surface of the drum, however, it is necessary that the coefficient of kinetic friction between the card and the drum should be greater than the coecient of static friction between the card 11a and the adjacent card 11b. It has been found that aluminum or steel provides a satisfactory surface for the drum. AIt is o f course necessary to keep the cards clean and `dry ill. order toprevent them `from sticking to each other.

The function of curved surface 33 is to permit the cards to start separating fromreach other before they reach the surface of the d mm.Y Thus as card 11a is pulled out of the input magazine by the rotating action of the drum, it in turn slides card 11b toward the top of Fig. 2, card 11b in turn'slides card 11C, and so forth. Curved surface 33 therefore permits the cards to be gradually channeled toward their destination, and at the same time permits any static friction bond which may exist between two adjacent cards to be broken before the actual feed point` ist. reached. c

'The function of -vertex 34 is to limit the number of cards which may be pulled from the magazine atl one time. Thus, depending upon the particular dimension which is chosen, between two and five cards at one time may be permitted to slide past vertex 34. The function of vertex 35 is to permit only one card at a time to pass between itself and the drum.

From actual operating experience, it has been found that even though the distance between the vertex 34 and thel drum may be adjusted to permit as many as live cards to pass through, lin most cases only a single card will actually pass. The phenomenon appears to be somewhat statistical in nature, with two cards at a time being passed beyond the vertex 34 about one time in 50. Vertex 35, on the other hand, whether it is presented with one or more cards, will permit only a single card to pass through at one time. Thus a very smooth, even feeding action is achieved,

Although the input magazine has been illustrated in Fig. 2 as including a lower retaining wall 30 and an end piece 31, actual operating experience has shown that these parts of the structure are unnecessary. In lieu, thereof, it is deemed preferable to employ a drum shield covering the surface of the drum for protecting the Vacuum therein, the drum shield being arranged so that it effectively replaces the end piece 31, a substantial aperture being provided between the drum shield and the vertex 35 so as to expose the cards to the pick-up drum.

The placement of the parts with respect to each other needs also to Ibe described. The inner surface of end piece 31 is aligned in a straight line with vertex 35. Vertex 35 is placed a small distance off center with respect to the drum. Thus a dotted line 37 represents the drum radius drawn in a direction which is parallel to the direction of card feed. It will be noted from Fig. 2 that vertex 35 is located somewhat above radius 37. In a specific embodiment of the invention, where very satisfactory results were obtained, a drum diameter of l Vinches were used, and vertex 34 was situated a half inch above line 37. Other specific information may conveniently be given in tabular form as follows:

Drum diameter, l0 inches Card size (IBM cards), 7% inches long, 3% inches wide, 7 mils thick Length of aperture between wall 31 and vertex 35,` 21/1 inches Radius of curved surface 33, 1.83 inches Distance of vertex 35 from drum surface, 8 mils Distance of vertex 34 from drum surface, 20 milsV Olfset-of vertex 34 from lower surface of Wall 32, 380

mils

Vertical offset of vertex 35 from vertex 34, 244 mils Distance of vertex 34 above drum radius 37, 1/2 inch 'Y Additional descriptionv of operation will now be given Withreferenceto Fig. 2. The stack of cards is pushed forward by' means of the pressure device 12. The cards whchare nearest to the surface of theV drum become separated from each other by means of the curved surface 33, as previously indicated. The sidewise movement of one or more cards past the vertex 34, in response to frictional thrust from the drum, provides additional separation. It is therefore evident that card 11a, which is ready to be picked up by the drum, is separated from the next card 11b by a denite amount of space. This pery mits the vacuum within the drum to become an aiding factor in picking up the card, since normal atmospheric pressure i5 applied to the back side of the card, whereas the front side faces against the vacuum at the surface of the drum.

In the operation of the card feed station of Fig. 2, an important point is the matter as to when each card is picked up. It is not permissible to have two cards picked up at once as this would result in the loss of the second card by falling from the drum during the revolution of the drum. As previously pointed out, the vertex permits only a single card to pass thereunder at any given time. Thus, when one card has passed under the vertex 35, it becomes possible for the next succeeding card to make contact with the drum.

It will'be noted that in the particolar example shown in Fig. 2 there is a substantial aperture between end piece 3l and vertex 35 (orl between a drum shield and vertex 35) and the length of the aperture may be 21/2 inches. It is therefore possible for the second card 11b to make contact with the drum surface before the first card 11a has passed entirely through the feed throat; for example, the second card may come in contact with the drum surface when ahalf inch of the'rst card yet remains to pass through vertex 35. The ultimate spacing between the first and second cards, however, is determined not by the time when the second card 11b first contacts the drum surface, but rather by the amount of time required to accelerate the second card up to theY drum speed. In actual practice it has been found that the time delay, or slippage, which occurs while the second card is being accelerated to drum speed is adequate to reliably provide a space -between successive moving cards. It has been found that the space between cards is random and varies from 1A in 2 inches. From the foregoing discussion, it is evident that the card feed rate may be conveniently adjusted by a suitable adjustment of the rotational velocity of the pick up drum,

Reference is now made to Fig. 3 wherein the card feed station of Fig. 2V is shown in vertical cross section, with like parts being identified by like numeralsf A suitable horizontal supporting mechanism for the input magazine is designated by numeral 38. It will be noted that the height of the input magazine as shown byV side walls 30 and 32 and the end piece 31 is somewhat less than the width of the cards. This relationship is not critical, and satisfactory operation has been obtained with a feed throat having vertexes 34 and 35, each of which extended less than half the width of the cards. On the other hand, equally satisfactory operation may be obtained where the vertexes 34 and 35 Vare ahnost equal to the card width, as shown. With speciiic values as shown above, satisfactory operation of the card feed station has beenrobtained at card rates as high as 4,000 per minute, The system requires no moving parts other than the drum, and it is relatively easy to adjust the drum for theone critical dimension, namely, Vthe spacing of vertex 35 must be sufficient to permit one card to pass, but not suicient to permit two cards to pass. n

It is therefore apparent that the present invention providesa novel card feed station which, without the use of any moving parts, provides a smooth, even card feed at a rapid rate to a conveyor which employs friction pickup. Operating rates with IBM punched cards may be obtained from two to four thousand cards per minute. Y

What is claimed as new is: Y

An automatic system forV continuously movingiflexible punched cards from a card stackk at a rate in excess of one thousand cards per minute and transporting them in a spaced sequential relation, said systetm comprising: a cylindrical drum rotatable abcut a vertical aXis, said drum including a peripheral surface formed of material providing a coecient of kinetic friction between a card and said surface which is greater than the coecient of static friction between two cards; means for supplying a partial vacuum to said peripheral surface during rotation of said drum; an input magazine xedly positioned with respect to said drum for supporting the card stack and tangentially presenting one card at a time to said peripheral surface; means associated with said input magazine for urging the stack against said peripheral surface; and a feed throat mounted on said input magazine and including a rst vertex spaced with respect to said peripheral surface so as to permit at least two cards to be simultaneously transported therebetween, a second vertex laterally displaced 'om said rst Vertex in the direction of motion of said peripheral surface and spaced therefrom so as to permit only one card :at a time to be transported therebetween, and a smoothly curved convex surface contiguous to said rst verter; for producing continuing lateral displacement of each card with respect to the preceding and succeeding cards of the stack when the stack is moving towards said peripheral surface, whereby when said drum is rotating each successive card of the stack is drawn out of said input magazine by means of kinetic frictional thrust from said peripheral surface aided by said partial vacuum and is thereafter retained on said peripheral surface solely by virtue of said partial vacuum.

References Cited in the le of this patent UNITED STATES PATENTS 1,515,986 `Wright Nov. 18, 1924 1,596,056 Mader Aug. 17, 1926 2,057,279 Shomaker Oct. 13, 1936 2,220,073 Belcher Nov. 5, 1940

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