US3527458A - Document feeding apparatus - Google Patents

Description

Sept. 8, 1970 w. P. BOND 3,527,453

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ATTORNEYS United States Patent 3,527,458 DOCUMENT FEEDING APPARATUS William Percy Bond, Langford, England, assignor to International Computers and Tabulators Limited, London, England, a British company Filed May 9, 1968, Ser. No. 727,886 Claims priority, application Great Britain, May 16, 1967, 22,614/67 Int. Cl. B6511 3/08 U.S. Cl. 271-30 7 Claims ABSTRACT OF THE DISCLOSURE A stack of documents is supported, with the documents on edge, on a sloping support member having a slightly upturned lower end. A weighted carriage, moveable down the slope under gravity, supports the upper end of the stack and the weight of the carriage is such that it cooperates with the upturned end of the support member to maintain the lower end of the document stack in a substantially constant position relative to the lower end as documents are fed in succession off the lower face of the stack. An air-jet feeding arrangement is used to select and feed these documents. Where the documents have more resistance to movement down the slope, the slope and/or the carriage Weight may be increased, and in this case a spring-biassed electromagnetically-released brake may be controlled by a switch at the upturned end to alternately operate and release the carriage in dependence upon the presence or absence of documents at the up turned end.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to document feeding apparatus, and in particular to apparatus for feeding documents from one face of a stack.

Description of the prior art A number of examples of apparatus for maintaining a stack of documents with the feeding face of the stack at a predetermined pick-off point are known. Usually, however, particularly in the case of so-called constant height pile-tables, where the document at the feeding face of the stack is required to be completely free to be fed away from the stack, it has previously been proposed to support the stack more or less vertically, with the individual documents horizontally in the stack, and to employ a positive mechanical drive to bodily raise the stack as documents are removed from its top face. Thus, this kind of stack supporting arrangement is relatively complex and costly.

Where apparatus has required documents to be stacked vertically, or nearly so, so that the document stack approaches the horizontal, or where the stack is inverted so that documents are fed from the lower end of the stack, it has previously been proposed to provide means for positively retaining the documents in the stack. In these cases the document feeding means has used devices, such as picker knives or suction caps which are required to be mechanically controlled to engage a document to be fed in order to withdraw the document from the retaining means. Thus, this kind of document feeder also requires a fairly complex feeding mechanism.

SUMMARY OF THE INVENTION According to the present invention, document feeding apparatus includes means for supporting a stack of documents each on one edge, the document support means being inclined generally at an angle from horizontal,

the lower end of said document support means being formed into a shallow upward bend; a weighted carriage supported on said document support means for movement down the incline under the influence of gravity to urge the stack of documents towards the lower end, the weight of the carriage being so adjusted that the carriage coacts with said upward bend to maintain the document stack with one face at a substantially constant position relative to the lower end of the support means; and means for selecting and feeding documents in succession from said one face of the stack.

Thus, in this apparatus, the documents at that face of the stack from which documents are fed are not positively retained but are completely freely supported. This allows the use of a very simple air jet for the purposes of separation and feeding of each document in turn.

Where the documents are large or thick, for example, it may be desirable that the force exerted on the stack to move it towards the feeding end of the support means be increased, as by increasing the weight of the carriage or by increasing the slope of the incline, and in this case it may be desirable to reduce the application of this force while the stack is correctly positioned on the support means. For this purpose the carriage may be fitted with a brake normally biassed to arrest movement of the carriage and means is then provided for releasing the brake when documents are absent from the upward bend of the support means. Such brake releasing means may include means (such as mechanically-operated switch) for detecting the presence or absence of documents at the upward bend, the detecting means being inserted in the energizing circuit for an electromagnetically-operated brake release arrangement. It has also been found advantageous under some conditions to energize such an electromagnet by a succession of electrical impulses.

BRIEF DESCRIPTION OF THE DRAWING In the drawing:

FIG. 1 shows, diagrammatically, a document feeding arrangement,

FIG. 2 shows a modification of part of the arrangement of FIG. 1, and

FIG. 3 is a schematic circuit diagram.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the FIG. 1 of the drawing, a support member 1 is arranged at a small angle from horizontal, and the lower end of the member 1 is smoothly curved into a shallow upward bend. In use documents 9 are stacked on edge along the support member 1. A carriage 2, consisting of a base block 3 and a stack support plate 4 is mounted on rollers 5 so that it is free to move along the support member 1. The rollers 5 run in guide grooves 6 in the member 1.

A feed bed 7 is provided having one end adjacent the curved end of the support member 1 extending above the member 1 and lying substantially parallel to the stack support plate 4. The bed 7 carries an aligning stop 8 positioned above the maximum height of the documents 9 of the stack on the support member 1.

The feed bed 7 also carries a number of apertures 10 arranged along its length. One side of the bed 7 forms a feeding face 11 and sheets are fed in succession along a feed path lying close to the face 11 of the bed 7. Only one aperture 10 is shown in the drawing. The apertures 10 are connected on the side of the bed 7 remote from the face 11, by means of branch tubes 12 to a manifold 13, and the manifold 13 is coupled to an inlet pipe 14 from a source of air under pressure (not shown). All the apertures 10 are arranged at an angle with respect to the 3 feeding face 11 of the feed bed 7, the angle being chosen so that'air issuing from the apertures emerges through the feeding face 11 as an air jet with a component of motion in the direction in which sheets are required to move along the bed 7.

Two further apertures and 16 are provided in the feed bed 7 opposite the position occupied by sheets 9. The aperture 15 is angled in the same way as are the apertures 10 and is connected'through a valve 17 to the air inlet pipe 14. The aperture 16 is also arranged at an angle to the face 11 of the feed bed, but in this case the angle is chosen so that an air jet issuing from the aperture 16 has a component of motion in the opposite direction from the normal sheet feeding direction. The aperture 16 is connected to the air inlet pipe 14 through a second valve 18.

The valves 17 and 18 are interconnected by an operating linkage 19 so arranged that it has two effective positions. In one position valve 17 is open and valve 18 is closed while in the second position, valve 17 is closed and valve 18 is open.

A pipe is provided and is connected at one end to the manifold 13. The free end of the pipe 20 is curved to a position in which a stream of air issuing from it impinges on the edges of those documents 9 of the stack which are supported on the bend of the support member 1, nearest to the feed bed 7.

The curvature of the bend of the support member 1 is so chosen in conjunction with the weight of the carriage 2 and the angle of the support member 1, that, with the stack of documents 9 upon the support member 1, the carriage 2 acts on the stack to maintain the free end of the stack in a substantially constant position relative to the end of the support member 1 and hence to the feed bed 7.

In operation, air is supplied under pressure to the inlet 14, the valve operating linkage 19 is adjusted to an initial position in which the valve 18 is open while the valve 17 is closed, and a stack of documents 9 is placed in position on the support member 1, the stack being arranged, as shown, so that all the documents 9 are supported on end. The carriage 2 is then allowed to move under the influence of gravity, along the member 1 to support one end of the stack. The carrier 2 then moves the stack along the member 1 so that the end of the stack nearest to the feed bed 7 occupies its correct position near the bed 7. At this point an air stream issuing from the pipe 20 acts on the documents 9 at the feeding end of the stack, and assists in separating these documents 9 from each other and from the stack.

An air jet issuing from the aperture 16 then, by providing a pressure differential across the gap between the bed 7 and the end of the stack of documents 9 causes the nearest document 9 to be attracted towards the bed 7. At the same time the component of motion of the air jet acting in this opposite direction to the normal document feeding direction causes the attracted document 9 to be moved to the position indicated at 9a by a broken line, with its upper edge abutting the alignment sto 8. Thus, the end document 9 of the stack is extracted from the stack and is aligned with the stop 8.

The operating linkage 19 is now moved to its second position, so that valve 17 is opened and valve 18 is closed. The extracted and aligned document 9 is now moved under the influence first of an air jet from aperture 15 and subsequently of jets from the apertures 10 along the feed bed 7 to follow the required feed path.

It will be realised that the feeding of an aligned document is initiated by the actuation of the linkage 19, and that the normal practice will be for the linkage 19 to be actuated as required by the apparatus to which the sheets are to be fed. Thus, the linkage 19 is normally to be controlled by whatever document utilization apparatus is to be supplied by the present feeding device, such as a document reading or sorting apparatus, for example.

It will be appreciated that since the purpose of the linkage 19 is to control the application and direction of air jets issuing from the bed 7, this purpose may alternatively be achieved by varying the direction of a single applied air jet instead of by the switching of the air supply.

Moreover one or more air jets may be controlled for this purpose by other means than a purely mechanical linkage. For example, valves may be controlled electromagnetically. Alternatively, the application or diversion of air jets or streams may he controlled by a fluid amplifier or by other fluid logic devices. I

It will be appreciated from the foregoing description that the combined action of the inclined stack support member 1 with its upward bend and the carriage 2 is to support the stack so that the next document 9 to be fed from the lower end is maintained in position to be selected and fed by an air jet, such as the jet from the aperture 16. The next document 9 is free from any restraint in order to enable its selection without the need for any mechanical operation to be performed. The aid stream from the pipe 20 assists in the separation of documents 9 at the upward bend of the support member 1, but it is to be understood that this auxiliary separation is not necessary in all cases.

The maintenance of the position of the document stack is dependent, as noted above, upon the relationship of the weight of the carriage 2, which tends to move the stack down the incline of the member 1, to the resistance to the movement of the stack offered by the upward bend of the member 1. However, particularly where the documents in the stack are large or relatively individually heavy, it may happen that the force required to be exerted upon the stack by the carriage 2 to initiate movement of the stack is so great that, once moving, the end downwards of the stack will tend to overspill off the end of the support member 1. Under these circumstances the apparatus may be modified as indicated in FIGS. 2 and 3 to relieve the down ward pressure on the stack exerted by the carriage 2 while the stack of documents 9 is correctly positioned on the support member 1.

In this case, as indicated in FIG 2, the support member 1 is mounted on a pivoted block 21, and is adjustable by a worm gear 22 meshing with teeth 23 formed on the block 21 to vary its angle of inclination. The worm gear 22 is mounted on a shaft 24 supported in bearings 25, the shaft 24 being rotatable under control of a hand wheel 26.

The carriage 2 includes a brake shoe 27 biassed by a spring 28 to act on one of the carriage rollers 5. An electromagnet 29 has an armature 30 connected to the brake shoe 27, the arrangement being such that energization of the electromagnet 29 causes the brake shoe 27 to be released from the roller 5.

A normally-closed microswitch 31 is supported on a bracket 32 beneath the support member 1 and has an operating lever 33 projecting through the support member 1 into the path of documents 9 in the stack at the upward bend.

In operation, the angle of inclination of the support member is increased, when dealing with a stack of large documents 9, and/or the weight of the carriage 2 is increased so that with the brake shoe 27 released from the roller 5, a stack of documents supported on the member 1 above the upward bend is moved from rest under the influence of the carriage 2. If the brake shoe 27 were maintained released, there would be a tendency, as the number of documents in the stack is diminished, for upward bend to fail to hold back the stack against the carriage 2. For this reason the brake shoe electromagnet 29 is connected to an energizing source 34 in series with the microswitch 31, as shown in FIG. 3. Thus, as the leading documents 9 of the stack are advanced to the upward bend in the support member 1 they actuate the switch 31 to open the energizing circuit for the electromagnet 29, allowing the brake shoe 27 to engage the carriage roller 5. The carriage is then held by the brake until the leading documents at the feeding face of the stack have been removed from the stack, when the switch 31 re-closes and the brake is again released.

It is preferred that the energizing source 34 is a pulse generator, providing electrical impulses to actuate the electromagnet 27. The frequency of generation of these impulses is far from critical, since as will be realised, a constant energizing current may alternatively be used but a frequency of a few impulses, say, four or five per second has been found to yield good results.

It will also be appreciated that the provision of means for varying the angle of inclination is not essential to the present invention. For example, if the feeding apparatus is to be used exclusively for documents of a particular kind, then the angle of the support member, and the weight applied to the carriage may be predetermined and not thenceforward varied. Similarly, it will also be appreciatetl that where the size of stack to be handled is fairly small, so that there is no great difference in force required to move the maximum or minimum lengths of stack down the incline then the balance between applied weight of the carriage 2 and resistance to stack movement offered by the upward of the support member may well be sufficient to ensure correct stack positioning without the need for the brake shoe 27 or the brake control described.

I claim:

1. Document feeding apparatus including means for supporting a stack of documents each on one edge, the document support means being inclined generally at an angle from horizontal, the lower end of said document support means being formed into a shallow upward bend; a weighted carriage supported on said document support means for movement down the incline under the influence of gravity to urge the stack of documents towards the lower end, the weight of the carriage being so adjusted that the carriage co-acts with said upward bend to maintain the document stack with one face at a substantially constant position relative to the lower end of the support means; means for feeding documents in succession from said one face of the stack; a brake on said carriage; means for normally biasing the brake to arrest movement of the carriage; and means for detecting the presence of documents at the upward bend, the detecting means being operative to release the brake in response to the absence of documents at said upward bend.

2. Apparatus as claimed in claim 1 in which said brake is spring biased to brake the carriage, includnig an electromagnet energizable to release the brake, means for energizing the electromagnet and a switch connected between the brake and the energizing means, the switch being operable by the presence of documents at said upward bend to interrupt the connection from the energizing means to the electromagnet.

3. Apparatus as claimed in claim 2, in which said energizing means includes means for generating a succession of electrical impulses at a predetermined frequency to energize said electromagnet.

4. Apparatus as claimed in claim 1 further including means for varying the inclination of said document support means.

5. Document feeding apparatus including a document support member for supporting one edge of each document of a stack of documents; a first portion of the support member inclined to the horizontal in a first sense and having a lower edge; a second portion of the support member inclined to the horizontal in a second sense opposite to said first sense and having a lower edge joined to the lower edge of the first portion; a weighted carriage supported on said first portion; means on said carriage operative to engage a rear end of the stack of documents and support the documents in planes inclined to the vertical in the second sense; the weighted carriage being effective to urge the documents to move down the inclined first portion and thence up the inclined second portion to maintain a front end of the stack at a substantially constant position on the second portion; and feed means operable to feed documents in succession from the front end of the stack.

6. Document feeding apparatus as claimed in claim 5 including a document feed bed having a feeding face substantially parallel to said planes and spaced from said substantially constant position; and first air means operable to produce a first air jet issuing from the feeding face of the feed bed having a component of motion along the feeding face and effective to feed the documents from the front of the stack in succession in a direction aligned with said component of motion.

7. Document feeding apparatus as claimed in claim 6 including second air means operable to produce a second air means operable to produce a second air jet issuing from the feeding face of the feed bed having a component of motion along the feeding face in opposition to the component of motion of the first air jet; a document stop on the feed bed; and control means selec-- tively operable to render said first air means operative to feed a document from the front of the stack into abutment with the stop and subsequently to render the second air means operative to feed the document away from the stop along the feed bed.

RICHARD E. AEGERTER, Primary Examiner

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