US3037768A - Apparatus for guiding and stacking continuous forms - Google Patents

Description

June 1952 T. H. ANDERSON ETAL 3,037,763

APPARATUS FOR GUIDING AND smcxmc CONTINUOUS FORMS 3 SheetsSheet 1.

Filed Sept. 26, 1960 INVENTOR THEODORE H. ANDERSON THEODORE F HAROLD P. BY .24

FIG.

3 Sheets-Sheet 2 T. H. ANDERSON ETAL June 5, 1962 Filed Sept. 26, 1960 FIG.

FIG.

June 1962: T. H. ANDERSON ETAL 3,037,768

APPARATUS FOR GUIDING AND STACKING CONTINUOUS FORMS Filed Sept. 26, 1960 3 Sheets-Sheet 3 United States Patent APPARATUS FOR GUEING AND STACKING CONTINUOUS FORMS Theodore H. Anderson and Theodore F. Flavin, Vestal, and Harold P. Wicklund, Endwell, N.Y., assignors to International Business Machines Corporation, New York, N.Y., a corporation of New York Filed Sept. 26, 1960, Ser. No. 58,386 7 Claims. (Cl. 270-73) This invention relates to apparatus for guiding and stacking continuous prefolded paper forms, and more particularly relates to such apparatus especially suitable for high speed printing machines and embodying means for automatically adjusting the height of a guide through which continuous prefolded and/ or transversely perforated paper forms are fed serially so that the exit end of the guide will be maintained at a substantially constant predetermined distance from the top of a stack of continuous forms as they are deposited in zig-zag fashion on a substantially stationary bed.

In order to assure reliable guiding and stacking of continuous prefolded forms, the distance between the exit end of the guide and the top of the stack must be maintained at a substantially optimum value, and in any event between maximum and minimum limits. As hereinafter more fully explained, the maximum distance corresponds to that at which two folds are in line and uncontrolled collapse or back folding will occur if such distance is increased even slightly. The minimum distance corresponds to that at which, if the guide were any closer to the top of the stack, the form following the one being folded would have to bend or deform in order to be driven through the guide. The optimum distance varies according to the distance between folds of the continuous forms, the speed at which such forms are being fed, and the inherent stiffness or rigidity of the forms.

It is known to provide means manually adjustable by an operator to move a guide, such as a throat means, upward from time to time as the height of the stack increases; but such arrangements are obviously impractical for high speed printers because they require constant attention of the operator and considerable skill to raise the throat means at the right times and to the proper degrees.

It is also known to control the level of the top of a stack of forms by providing automatic means for lowering a stack-supporting platform as necessary to keep the top of the stack at a substantially constant height. However, this type of automatic control is not suitable for high speed printing machines, especially those of the skipline type and/ or those capable of stacking relatively large forms into relatively heavy stacks. In skip-line printing machines, the forms are fed to the printing mechanism and therefrom to the stack in intermittent random fashion, with varying degrees of displacement and hence acceleration between successive irregularly spaced lines of printing. It means are provided to move the platform to maintain the top of the stack at a constant height below a fixed throat means, it is apparent that movement of the platform will become more sluggish as the stack builds up and increases the load thereon. Sluggish re sponse cannot be tolerated in the high speed stacking required in high speed printers. Moreover, a movable platform must be of suificient strength and hence weight to support a stack of forms of maximum permissible height and weight, resulting in a relatively high tare weight for the platform and hence greater inertia. Also, the distance of the movable support platform from the floor will vary according to the height of the stack, making it difficult to remove stacked forms from the platform.

The principal object of this invention is therefore to grills 11, 12, respectively,

3,937,768 Patented June 5, 1962 provide an improved guiding and stacking apparatus especially suitable for stacking continuous 'prefolded forms at high speed, such as in high speed printing machines.

Another object is to provide an improved apparatus of the above type which is less expensive to manfacture, is more rapid in its response to changing height of the stack, and is unaffected by the weight of the forms on the stack.

According to the invention, the improved guiding and stacking apparatus comprises means automatically operable to adjust the height of a relatively lightweight throatproviding guide means as necessary to maintain the exit end of the guide means at a substantially constant height (or within predetermined limits) above the top form of a stack of continuous perforated and/0r prefolded forms as they are deposited on a fixed bed or platform, which may be the floor or a stationary member at a fixed distance from the floor.

The apparatus also preferably embodies means permitting adjustment of the optimum distance between the exit end of the guide means and top of the stack to suit the particular characteristics of the forms being stacked. The apparatus also preferably embodies means for permitting the guide means to be raised whenever desired to facilitate removal of the forms from the fixed bed.

The foregoing and other objects, features, and advantages of the invention will be apparent from the following more particular description of a preferred embodiment of the invention, as illustrated in the accompanying drawings.

In the drawings:

FIG. 1 is a rear elevation view of a guiding and stacking apparatus embodying the invention;

FIG. 2 is a fragmentary side elevation view, to enlarged scale, of the left side of FIG. 1, with a counterbalancing mechanism removed for clarity;

FIG. 3 is a section view, to enlarged scale, along the line 3-3 of FIG. 1;

FIG. 4 is a section view, to enlarged scale, along line 4-4 ofFIG. 1 showing a detent mechanism;

FIGS. 5A, 5B, 5C are schematic side views respectively showing the maximum, minimum, and optimum distances of the throat from the top of the stack; and

FIG. 6 is a diagrammatic view of an electrical circuit for the apparatus.

Description As shown in FIGS. 1 to 3, the improved guiding and stacking apparatus comprises a generally vertically movable guide means, designated generally 10. This guide means may comprise front and rear transversely spaced each comprising a plurality of vertically spaced rods or wires having hook-like upper and lower ends which crook around and are welded to horizontal .tie bars. At their ends the upper tie bars for the respective grills 11, 12 are secured in spaced relation to outturned ears 13 on respective upper brackets 14, only those for the left side of the apparatus as viewed in FIG. 1 being shown in FIG. 2. Similarly, the ends of I the lower tie bars for the grills 11, 12 are secured in spaced relation to outturned ears 15 on a lower cross plate 16. Each upper bracket 14 has an inturned portion which projects through and rides ina vertical slot 17a in the base of a suitably supported fixed U-shaped guide 17 and overlies and is screwed to the upper end of a corresponding vertical gear rack 18. Each lower plate 16 has an inturned portion disposed below the fixed guide 17 and underlying and secured to the lower ends of the racks 18. The guide means 10 and racks 18 are thus secured to move in unison.

The racks 18 are movable vertically in unison by respective pinions 19 carried by a single drive shaft 20 that is driven by a reversible-type motor M. This shaft is journaled in bearings (not shown) carried in openings in the side portions of the fixed U-shaped guide 17, and the motor M is carried on a bracket 17b suitably secured to said guide.

-A movable support means comprises a horizontal tie plate 21 which is disposed rearward of the rear grill 12 and carries two depending members 22, 23 that, in turn, respectively have'feet carrying a light source S and a photo-electric cell PC. As best shown in FIG. 3, the

member 23 (and also, though not shown, the member 22) comprises a downwardly extending arm that has a laterally extending L-shaped projection formed integrally with its upper end. The outer part of these projections on members 23', 22 are lap welded to opposite ends of the tie plate 21; and the other parts, which are joined to the arms, extend transversely and have aligned bores 24:: which encircle a shaft 24. The arm of'each member 23, 22 has lateral sliding contact within a corresponding vertical groove 25 provided in the facing sides of the corresponding racks 18. The racks 18 and arms of each member 23, 22 have slidably guided contact with the side walls of the fixed U-shaped guide 17. The side walls are well lubricated to reduce friction, or rollers (not shown) may be provided for the same purpose. Thus,

the members 23, 22 are slidably movable relative to their corresponding racks 18.

1 Shaft 24 extends horizontallyand parallel to, but just forward of, the plate 21. Shaft 24 carries two pinions 26 each engageable with a corresponding rack 18. A knob 27 secured to shaft 24 is manually rotatable for rotating the pinions 26 and thereby walking the members 22, 23, tie plate 21, shaft 24 and knob 27 upwardly or downwardly relative to the then stationary racks 18 as permitted .by the sliding fit provided. by grooves 25 and the guiding action of guides117. Thus, the position of the members 22, 23 and hence of the light source S and photo cell PC can be preadjusted relative to the racks 18 and thereby relative to the guide meanssecured to the racks. The purpose of this preadjustment is to preselect a desired nominal distance between a throat 28 and the light source S and cell PC, for reasons hereinafter explained. This throat is defined between'the lower or exit ends of the grills 11, 12 of the guide means.

- 'To maintain this preadjustment and normally prevent relative movement of the members 22, 23 and hence of light source S and cell PC relative to the racks 18, arsuitable holding or latching mechanism is provided. This mechanism may comprise a detent 29 rockably mounted on a pin 30 carried by an outturned ear 31 on the depending arm of member 22. This detent has a finger which normally engages aselectable one of the'teeth .of rack 18, and is manually rockable out of such engagement when the position of the members 22, 23 is to be pread justed from time to time relative to the racks by rotation of knob 27 in the manner above explained.

To prevent the racks 18. and members 22, 23'from dropping relative to the fixed guides 17 due to their weight while said racks and support means are latched together as an assemblage by detent 29, and also prevent the racks from dropping when the detent is unlatched, a counterbalancing mechanism 32 is provided. This mechanism a clock-type coil spring (not shown) connected at one end to, and wound aroundthe end of, shaft 20 remote-from motor M; or, if preferred, it may be of the typeknown in the art as a negator spring.

A pair of rear guide posts 33 (seeFIGS. 1, 5A)*and 7 front guide posts 34 are suitably adjustably secured to and project upwardly from a stationary bed 38 on which the forms are stacked between the posts. The posts of each pair arerpreferably interconnected by horizontal 4 forms F of different widths. These posts 33, 34 are arranged at right angles to the light source S and photo cell PC. As shown in FIGS. 5A, 5B, 5C these posts assure that the forms F will be constrained to pile evenly without sliding laterally off the edges of the stack.

The light source S emits a light beam B which passes across the stack of forms F in a direction parallel to the planes of the grills 1'1, 12 and between the oppositely arranged pairs of guide posts 33, 34. So long as this light beam to cell PC passes above the top form F stacked on the stack, it will be only momentarily interrupted as the forms sway back and forth toward and away from the reader as viewed in FIG. 1 (or laterally as viewed in FIGS. 5A, 5B, 5C). When the stack height increases suficiently for the top form to block the light beam oif from cell PC for more than-a predetermined slight time, the cell will initiate operation of motor M to elevate the racks 18, grills 11, 12 and throat 28, and the support means 21, 22, 23 (and thus the source S and cell PC then adjustably secured thereto) relative to the stack of forms F. The light source S and cell PC and throat 28 will be elevated until light beam B can once again continually reach cell PC except for the intermittent momentary interruptions caused by weaving of the forms across the pathof the beam B after such forms leave the throat 28 and before they are piled on the top of the stack.

Operation of the motor M is controlled by an electrical circuit shown in FIG. 6. As illustrated, this circuit comprises a shut-cit switch 39 which is interposed in a negative line N and is closed to permit operation of the motor M and opened to prevent such operation and shut off the light source S, which is interposed between branches of line N and a positive line B. A relay 40 is energized so long as the light beam B gets to cell PC and completes a circuit across the lines N and B via'cell PC and relay 40.

With relay 40 energized, the motor M can be driven one way to move the rack and support assemblage 18, 21, 22, 23 down by closing a normally open manual switch 41 and thus completing a circuit across the lines N, B via one winding of motor M, switch 41 and the front contact of relay 40. When the light beam B is cut oil from cell PC, the relay 40 will be deenergized as shown in FIG. 6. The motor M will be driven the opposite way to elevate the -assemblage 1 8, .21, 22, 23 whenever the relay 40 is deenergized and completes a circuit across the lines N, B through another winding of motor M, a normally closed upper limit switch 42 and the back contact of relay 40. Also, provided switch 42 is closed, the assemblage 18, 21, 22, 23 may be elevated independently of relay 40 by closing a normally open manual switch 43 to complete a circuit bypassing the back contact of relay 40 and connecting the lines N, B through said other winding of motor M and switches 42, 43. The normally closed switch 42 is opened toprevent operation of the motor M in an assemblage-elevating direction whenever a projecting piece 46 laterally secured to one of the racks 18 (see FIG. 1)

' strikes'and shifts an insulated plunger 47 against resistance of a bias spring 48; or if preferred, switch 42 may be of a leaf-spring like type normally closed and rocked open by the plunger 47. V V I FIGS, 5A, 5B, 5C illustrate the, maximum, minimum and optimum distances, respectively, at which throat 28 can be preadjusted above the top form of the stack (or the bed 38 if no'form s areonthe bed) and still permit the guiding and stacking apparatus, to function. If the throat-to-top of stack distance is increased above the maximum'illustrated in FIG, 5A, backfolding of the forms 'canoccur; the lower form (the one, just below perforation or fold X) can bend leftward instead of rightwardasview ed in this figure. If such distance is less thanthe illustrated in"FIG. 5B, the. form will cross bars 35 so that they may be adjusted in unison intend to deform unduly in the throat 28 and prevent smooth feeding and stacking. The optimum throat-totop-of-staek distance is between these two upper limits,

such as illustrated in FIG; 5C. This optimum distance can actually be a range of distances well within the upper and lower limits illustrated in FIGS. 5A and 5B. So as not to have the motor M operate almost continuously as forms are fed through the throat 28 at high speed, the circuitry above described is intended to maintain the nominal throat-to-top-of-stack distance within an optimum range. The width of this range is a function of the response time of the cell PC, pick up time of relay 40, and inertia of the guide means 10, racks 1%, driving pinions 19, etc. However, the nominal distance is preadjusted by rotation of the knob 27, in the manner above explained.

SUMMARY OF OPERATION Assume initially that the nominal optimum distance it is desired to maintain the throat 28 above the top of the stack has been previously preselected, taking into account the physical characteristics of the particular forms F; that detent 29 was thereafter latched to thereby space the light beam path such preselected optimum distance from the exit end of the throat 28; that switch 39 is closed; that a number of forms F have already been stacked on bed 38 between the guide posts 33, 34; and that the forms have been piled high enough so the top form of the stack has just blocked off the light beam B from photo cell PC.

As soon as relay 40 becomes deenergized due to the cut off of light to cell PC the various components will be in the respective positions shown in FIGS. 1 to 4, 5C and 6. The circuit including the other winding of motor M, switch 42 and the back contact of said relay will be completed to cause the motor M to drive the pinions 19 through shaft 20 and thereby move the assemblage 18, 28, 21, 22, 23, S, PC upward relative to the top of the stack. Shortly after the light beam B can again get to cell PC, relay 40 will be reenergized, thereby stopping the motor M and hence stopping upward movement of the throat 28, source S and cell PC at the upper part of the optimum range, which upper part is somewhat above the top form. The weaving of the forms transversely across the light beam B will not interrupt the light to the cell PC long enough to deenergize relay 40. However, each time the top form of the stack again blocks the light beam B, the relay 40 will become successively deenergized to raise the throat 28 a given increment and then reenergized.

Eventually the assemblage 1'8, 21, 22, 23, S, PC will be elevated to the point where projection 46 strikes plunger 47 and opens upper limit switch 42 thus preventing further elevation of said assemblage by the motor M even if the operator should inadvertently close switch 43.

The forms F should then be removed from the apparatus. If different sized forms F are now to be stacked, the nominal optimum distance should be readjusted accordingly by unlatching detent 29, rotating knob 27 to effectively reposition the throat 28 relative to the source S and cell PC, and then relatching detent 29. Switch 41 is then depressed to activate the motor M to lower the assemblage 18, 28, 21, 22, 23, S, PC; it being noted that since no forms interrupt the light beam B, the relay 40 will be energized via cell PC. When the assemblage is lowered to its starting position, the light beam B will be interrupted by a shield 50 projecting upwardly from the bed 38 to cut off the light to cell PC and thus deenergize relay 40 to shut off the motor M. This will positively prevent the assemblage from moving down far enough to damage the cell PC and source and thus desirably permit the operator to maintain the switch 41 depressed until the motor stops, without fear of damaging the apparatus.

Forms F are then fed down through the grills 11, 12 of the guide means 10. The apparatus will operate as above explained to intermittently elevate the assemblage 18, 28, 21, 22, 23, PC, S in increments.

In the event of a misfeed or if the operator desires to move the assemblage upwardly to facilitate removal of a stack of less than maximum height, he need merely depress switch 43 and ascent of the assemblage will terminate automatically by and upon opening of upper limit switch 42.

While the invention has been particularly shown and described with reference to a preferred embodiment thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and details may be made therein without departing from the spirit and scope of the invention.

What is claimed is:

1. In an apparatus for guiding and stacking continuous prefolded paper forms on a bed, the combination of guide means providing a throat through which such forms are fed serially for stacking in plies in zig-zag fashion on the bed, said throat being disposed above such stack and always lying in a plane substantially midway between the folded edges of the forms when stacked, means for sensing the height of such stack, and means controlled by the sensing means for automatically moving the guide means translationally upward away from the bed as necessary to maintain the exit of the throat at a substantially constant preselected distance above the uppermost form on the stack, said preselected distance being sufiicient to permit passage of the forms through the throat without undue angularity at the prefolds and small enough to prevent backfoldin-g or uncontrolled collapse of the forms.

2. In an apparatus for guiding and stacking continuous prefolded forms, the combination of guide means ineluding two generally parallel closely spaced grillworks of low inertia movable only translationally and providing a throat through which such forms are fed serially, means providing a bed on which such forms are stacked in plies in zig-zag fashion after leaving said throat, means for sensing the height of the stack, and means controlled by the sensing means for automatically elevating the guide means translationa'lly a predetermined amount whenever the height of the stack rises to a point where the top form on the stack is less than a certain distance from the exit end of the throat, whereby the guide means will be elevated intermittently in increments and asynchronously according to the thickness and rate of deposition of the forms as necessary to maintain the exit end of the throat within a defined height range above the top of the stack, said range corresponding to heights which are sufficient to permit passage of the forms through the throat without undue angularity at the prefolds and small enough to prevent backfolding and uncontrolled collapse of the forms.

3. In an apparatus for guiding and stacking continuous prefolded forms, the combination of guide means movable only translationally and providing a throat through which forms are fed serially, means providing a normally stationary bed on which such forms are stacked in plies in zig-zag fashion after leaving said throat, means for sensing the height of the stack, said sensing means including a photo-electric cell and light source which are disposed at opposite sides of the stack and so arranged that the light beam emitted by said source is substantially parallel to the prefolded edges of the forms, and means controlled by the sensing means for automatically translationally elevating the guide means when the light beam is interrupted by deposition of a form on the stack thereby to maintain the exit end of the throat at a substantially constant preselected distance above the uppermost form on the stack, said controlled means being insensitive to temporary interruption of the light beam resultant from the weaving of forms back and forth thereacross after they leave the throat and before they are fully deposited on the stack, said preselected distance corresponding to a desired value suflicient to permit passage of the forms through the throat without undue angularity at the prefolds and small enough to prevent backfolding or uncontrolled collapse of the forms.

4. In an apparatus for guiding and stacking continuous prefolded orms, the combination of guide means pro viding a throat through which such forms are fed serially, said throat being in the nature of elongated slots disposed above and extending in a direction transverse of the stack across substantially the full width thereof always at a point substantially midway between the prefolded edges of the forms when stacked, means providing a bed on which such forms are stacked in plies in zig-zag fashion after leaving the throat, means for sensing the height of the stack, the last-named means including a light source for directing a light beam transversely of the stack in a direction substantially parallel to said edges and slot, and a photo-electric cell responsive to said beam, and means controlled by the sensing means for automatically raising the guide means translationally a predetermined amount whenever the height of the stack rises to a point where the top form thereon is less than a certain distance from the exit end of the throat, whereby the guide means will be elevated intermittently in increments and asynchronously according to the thickness and rate of deposition of the forms as necessary to maintain the exit end of the throat within a defined height range above the top of the stack.

5. In an apparatus for guiding and stacking a continuous strip of prefolded forms being fed from a highspeed printer at a variable speed, the combination of means providing a bed on which such forms are stacked in plies in zig-zag fashion, guide means providing a throat which is always disposed generally above the center of the bed, said throat being movable solely in a substantially vertical plane and providing an orifice through which the forms are fed serially, a driven member connected to said guide means, motor means for moving the member, a photo-electric cell and a light source operably connected to said member and disposed adjacent opposite sides of the stack such that the light beam emitted by the said source is substantially parallel to the prefolded edges of the forms and is a preselected distance below the throat, said cell being insensitive to momentary interruptions of the light beam from the source during weaving of the forms back and forth across the beam after they have left the throat and before they are fully deposited on the stack, and an electrical circuit including said cell conditioned responsively to a prolonged interruption of said light beam by a form deposited on the stack to activate said motor means to move the driven member and thereby translationally move the guide means and cell and source concurrently away from the bed until the light beam is once again only temporarily interrupted, whereby said circuit ill be conditioned automatically and asynchronously according to the thickness and rate of deposition of the forms as necessary to maintain the exit end of the throat at substantially said preselected distance above the form last deposited on the stack.

6. The combination according to claim 5, including means adjustably connecting said cell and source with said driven member, thereby to permit preadjustment of said distance to a preselected value suitable for the physical characteristics of the particular forms to be stacked.

7. The combination according to claim 5, wherein said guide means comprises two generally parallel closely spaced grills of light weight and low inertia to provide a minimum of frictional contact with the forms and also be capable of rapid starting and stopping.

References Cited in the file of this patent UNITED STATES PATENTS 2,525,311 Peyrebnme Oct. 10, 1950 FOREIGN PATENTS 523,838 Italy Apr. 19, 1955 748,832 Great Britain May 9, 1956

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