Panel Counting, Collecting And Gating Apparatus

Abstract

A continuously conveyed series of uniformly dimensioned panels of thin sheet material are counted and stacked from the bottom against an abutment edge of a stationary but rotatable cam plate. When a predetermined number of panels is collected in the stack, the cam plate is rotated to lift the stack into a rotating roll nip for conveyance to a second roll nip. Removal of the stack from the proximity of the collecting cam plate is completed by the second roll nip after the collecting cam has resumed a stationary, collecting position.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the art of thin sheet material handling and more particularly to the paper converting industry wherein a paper web of indefinite length is drawn from a large roll and cut into small panels of more convenient size, a discrete number of the small panels being counted and collected in a face-to-face stack for protective packaging and distribution.

2. Description of the Prior Art

In the process of converting paper from large roll stock, as received from the finish end of a papermaking machine, to individual packages containing a select number of uniformly sized panels, it is customary to cut one rectangular panel dimension by slitting as the web is reeled from the roll. The other panel dimension is cut by rotary knives disposed transversely of the web length as the web is fed continuously thereto. If it is desired to collect these dimensional panels into face-to-face stacks containing some particular number of panels, it is desirable to count, collect and deliver the stacks as rapidly as received from the transverse cutter. In the past, it has been necessary to run the rotary knife and therefore the slit web supply at a speed below capacity due to the greater time required of the counting, collecting and delivery operations by prior art methods.

One such prior art method is that disclosed by U. S. Pat. No. 2,708,760 to Lewis C. Pearce. The significant shortcoming of such prior art is the necessity to clear a completed stack of panels from the collecting station before the arrival of the first panel of the next stack.

It will be appreciated that the lateral structural integrity of an aligned stack of paper panels to resist shear separation is sustained only by the surface friction between individual sheets. When the stack is accelerated from the static collecting position by a dynamic force frictionally applied to the bottom panel, inertia of the stack resists such acceleration. Any given stack of panels, therefore, has a maximum lateral acceleration value whereat the opposite acting inertia force exceeds the frictional force holding the stack together.

Although, the frictional restraining forces may be augmented by accelerating the stack between a roll nip, even this expedient has a relatively low limit when compared to the velocity capacity of current panel supply systems. Long panels, rapidly supplied with short separation distances, quickly press the capacity of prior art systems due to the fact that the first panel of a new stack will close the separation gap between it and the last panel of a completed stack and become entangled therein before the completed stack may be removed from the collecting station. Accordingly the supply velocity must be reduced to a magnitude commensurate with that of the stack discharge period.

It is, therefore, an object of the present invention to provide a rapid response, counting, collecting and stack transfer method and mechanism wherein a succeeding stack may be started before the preceding completed stack is completely removed from the collecting station proximity.

Another object of the present invention is to provide a collecting and transfer method and mechanism wherein a completed stack discharge time period may overlap into the time period required to collect a predetermined number of panels.

A further object of the present invention is to provide a simplified collecting and discharge method and mechanism wherein the stack aligning fence is integral with the discharge propulsion roll.

SUMMARY

The foregoing objects of the present invention are served by a rotary gate at the panel collecting station in the form of a notched cam wheel. Only the ends of the panel stack need be vertically supported by the notched cam.

Panel stacking at the collecting station is preferably from the bottom up from an endless belt conveyor having a break in the support plane at such a distance ahead of the notched cam as will allow the panel trailing ends to spring up and above the leading edge of oncoming panels.

Counting may be performed by any suitable means such as a photoelectric sensor which will emit a trigger signal to an electrically actuated single revolution clutch in the notched cam power train.

As the collecting notch in the cam rotates, the gate abutment is revolved away from the stack leading edge and simultaneously, the supported end portion of the stack is lifted into a roll nip between a constantly rotating overhead wheel and the back periphery of the cam wheel. This action is necessary only to transfer the stack end into a second, constantly turning, roll nip which completes the stack removal.

Meanwhile, the notched cam completes the one revolution transfer starting function and returns to the stationary collecting position where a new stack is begun even before the completed stack is completely removed from the collecting station proximity.

BRIEF DESCRIPTION OF THE DRAWINGS

Relative to the drawing wherein like reference characters designate like or corresponding parts throughout the several views:

FIG. 1 is an elevational schematic of the invention in collecting position;

FIG. 2 is an elevational schematic of the invention in the initial stack transfer position;

FIG. 3 is an elevational schematic of the invention in the final stack transfer position;

FIG. 4 is a dimensional comparison chart relative to the panel length and cam wheel periphery;

FIG. 5 is an event sequence time comparison chart for the invention;

FIG. 6 is an isometric view of the notched cam showing the one revolution clutch in partial section.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring initially to FIG. 1, there is shown an endless belt conveyor 10 carrying a continuous series of thin sheet material panels P. The source of panels P is irrelevant as to this invention but in the normal use environment the panels are delivered with uniform longitudinal dimension L (FIG. 4) and serially separated by a gap G as the product of a continuous sheet web passing under a rotary shear.

Since the stated functional objective is to assemble the series continuum of single panels into face-to-face stacks, each containing a predetermined equal number of panels, it is necessary to first count the panels carried by the belt 10 past a fixed point for the subsequent purpose of delineating a stack group for segregation. This counting function may be performed by many known devices which emit an electrical impulse when the set number of panels P pass the reference point and automatically reset to start the count over with the next successive panel. Selected for the purpose of this disclosure is a photoelectric relay device having a light emitter 15 for directing a collimated beam 16 across the panel P conveyance path. A photon sensitive receiver 17 responds to each interruption of the beam 16 when a panel P passes thereacross by emitting a counting pulse. The series of counting pulses are received by a digital counting relay (not shown) which conducts a power signal when the predetermined number of count pulses have been accumulated. Upon conduction of the power signal, the digital counting relay circuit resets to start the count over again with the next successive count pulse.

A slight break is provided in the conveyance plane of belt 10 between sections 10a and 10b as the belt 10 is drawn over turning roll 12 by the belt pulling roll 11 at the terminal end of the material transfer course. The length of belt section 10b and the obtuse angular divergence thereof from section 10a is selected to give an overhanging projection 14 to the trailing ends of panels P above the belt section 10a approach to the plane angle break point around turning roll 12. An air jet from conduit 13 supplements the material rigidity of panels P to hold the ends 14 above the approach plane 10a and further to gently urge the leading ends of panels P to a flat entrance position into the wedge thereby accumulating a stack of panels S from the bottom.

It is important to specify a belt 10 providing a static frictional force between the surface thereof and a contiguous panel P face that is greater than the maximum dynamic frictional force between panels so that belt section 10a will deliver the final panel of a stack S to its properly aligned position against the leading edge abutment fence 22 in the notch 25 of gating wheel 20.

When the desired number of panels P have been accumulated, the counting system emits a power pulse to a single revolution clutch (FIG. 6) in the power train to cam wheel 20. As cam wheel 20 revolves (FIG. 2), point A at the circular periphery thereof lifts the leading edge portion of the stack off the notch 25 support surface 23, away from the fence portion 22, and into nip contact with the constantly rotating transfer nip roll 21. Due to the rapid response time of single revolution clutches of Type 6 as specified by Bulletin No. 239, Jan., 1959, Hilliard Corporation, Elmira, N.Y., and the fact that not all of the stack S mass is subjected to acceleration parallel with the panel face shear planes, the surface velocity of cam wheel 20 has matched the surface velocity of transfer roll 21 by the time point A on cam wheel 20 reaches the nip position of FIG. 2. Thereafter, removal of the entire stack S from the holding position above belt section 10b is started.

As the circular periphery of cam wheel 20 between points A and B opposite from the notch 25 continues rotational nip cooperation with the transfer roll 21, the stack S leading edge is delivered into the nip between constantly rotating removal rolls 30 and 31. Transfer table 26 between wheel 20 and roll 30 may be useful to prevent spreading of the individual panel ends during transfer from one nip to the other.

As removal of a completed stack S progresses under the nip propulsion of removal rolls 30 and 31, the first panel P of the next stack continues unabated to advance along the final belt section 10b beneath the trailing end 14 of completed stack S toward the cam wheel 20 -- permissibly at a greater velocity than that of the withdrawing completed stack. Since cam wheel 20 is stopped after only one revolution, however, the fence 22 and end support surface 23 is quiescently awaiting the arrival of said next first panel. No interference is given the remaining portions of the withdrawing stack S due to the relief clearance allowed by the notch 25 in the stationary cam wheel 20 opposite from transfer roll 21. Accordingly, the completed stack is leisurely drawn from the collecting station by the removal rolls 30 and 31 even after the next stack has accumulated several panels.

Although obvious to those of ordinary skill in art from the foregoing functional description of my invention, the disclosure hereof may be better served by an expanded explanation of certain design parameters and components. The first of such elucidations is represented by the dimensions C and D of FIG. 1. Since the only advancement of a stack S given by nip cooperation between wheels 20 and 21 is to deposit the stack with the nip between rolls 30 and 31, it is necessary that arc C of cam wheel 20 between points A and B opposite from notch 25 be at least equal or slightly greater than the centerline separation distance D between rolls 21 and 31. Moreover, as illustrated by FIG. 4, distance D is less than the length L of a panel P. The basis of these dimensional relations is to assure that one revolution of the cam wheel 20 will securely deposit a stack of length L within the propulsion nip between rolls 30 and 31.

Other critical parameters of my invention are the surface velocities of the belt 10 and the rolls 20, 21 and 30, 31. These velocities are coordinated with the foregoing length parameters to yield a time-event sequence similar to that represented by FIG. 5. In that figure, dimension g represents the maximum time lapse for one revolution of the cam wheel 20. Dimension d is that time period required to discharge a completed stack from the proximity of the collecting station at notch 25. Dimension d' is the maximum period allowable for the discharge of such completed stack. Dimension l is the time lapse between the leading edge of one panel to the leading edge of the next successive panel. Dimension k is the time interim of a gap between the trailing and leading edges of two successive panels. Dimension s is the time required for the accumulation of a stack of 4 panels. Moments in the event sequence are measured from the trailing edge point of a stationary panel at the collecting station. At moment o, the trailing edge of the last panel P of a stack S arrives at the reference point as represented by the minor lineations under time intervals l.sub.1 through l.sub.4. Stacking interval s is complete and a simultaneous pulse from the counting relay engages cam wheel 20 to start the running of gating and discharge period g and d, respectively. The period g must be equal to or less than the period l so that when the trailing edge of the first panel of the next stack arrives at the reference point at moment 2, the cam wheel 20 is stationary in the collecting position. Since the invention precludes interference between the withdrawing stack and the newly accumulating stack, however, interval d may be extended beyond moment 2 to as much as moment 8 when the next succeeding stack is complete and ready for discharge.

A key element in the present invention is that of the single revolution clutch 40 shown by FIG. 6 in partial section. Power sleeve 41 is driven continuously by belt 42 running in sheave 43. Cam wheel drive shaft 44 is selectively engaged with the power sleeve 41 by a clutch mechanism 45 of the Sprag type which comprises a cage 46 for roller cams 47. The geometry of cams 47 is such that no rotational interference between race surfaces 41a and 44a is raised at one angular position of the cage 46 about the centerline thereof. When the cage is rotated to a second relative position, the cams 47 are wedged to a lock position between race surfaces 41a and 44a. The cage 46 is spring biased to the lock position. An abutment portion 48 on cage 46 is designed to cooperate with frame mounted pawl 49 when urged to the engaged position by spring 50. Disengagement of the pawl 49 from abutment 48 occurs at the instance of solenoid 51 actuated by the power pulse from the counting relay.

When the pawl 49 is in the engaged position, attempted rotation of the cage 46 thereagainst angularly displaces the cage 46 against spring bias to the first, free running, or disengaged position. Upon energization by a counting relay power pulse, the solenoid shaft 51a momentarily lifts the pawl 49 off the abutment 48. Cage spring bias angularly shifts the cage to the second, engaged position thereby transmitting rotary power to drive shaft 44. Since the counting relay pulse is only momentary, however, bias of the spring 50 immediately urges the pawl 49 back against the cage ring outer periphery 52 which slides thereon until contact with the abutment 48 is resumed after one complete revolution.

It will, of course, be understood that various changes may be made in the form, details, arrangement and proportions of the parts without departing from the scope of the invention as set forth in the appended claims.

Claims

I claim:

1. Thin sheet material panel stacking and transfer apparatus comprising:

a. panel delivery means providing a substantially continuous supply of serially aligned thin sheet material panels;

b. counting means for discerning the delivery of a discrete number of said panels and marking the event by emission of an actuation signal;

c. stacking means for accumulating a stack comprising said discrete number of panels in face-to-face and leading edge juxtaposition at a stacking station;

d. stack removal conveyance means for removing a stack of said panels from said stacking station; and,

e. stack transfer means for transferring the leading end of an accumulated stack from said stacking station to said removal conveyance means, said transfer means comprising a first roller having a substantially full circle peripherial surface and a second roller having a partial circle peripherial surface, said second roller peripherial surface also comprising a notched portion therein, said notched portion having an abutment surface for receiving and aligning leading edge portions of said panels to cumulatively form a stack leading end, said first and second rollers being relatively aligned to nip said stack leading end between said first roller peripherial surface and the circular portion of said second roller peripherial surface upon rotation of said second roller partial circle through a common radial plane between the axes of said first and second rollers.

2. Apparatus as described by claim 1 wherein said panel delivery portion comprises a first panel transfer plane and said stacking means comprises a second panel transfer plane, said first and second transfer planes intersecting at an obtuse included angle, the length of said stacking station between said transfer means abutment surface and the point of said transfer plane intersection being less than the length of said panels whereby trailing end portions of accumulated stationary panels project beyond said point of intersection and each panel added to said stack is inserted at the interface between said second transfer plane and the previously added panel face.

3. Apparatus as described by claim 1 wherein said first roller is operated in substantially continuous rotation.

4. Apparatus as described by claim 3 wherein rotational power delivered to said transfer means is intermittently transmitted by selectively engaged single revolution clutch means.

5. Apparatus as described by claim 4 wherein engagement of said single revolution clutch means is prompted by said counting means actuation signal.

6. In combination with delivery means providing a substantially continuous series supply of thin sheet material panels; counting means for discerning the delivery of a discrete number of said panels; a stacking station for accumulating a stack of said discrete number of panels in face-to-face juxtaposition; stack removal means for conveying said stack from the proximity of said stacking station; and cooperative roll nip propulsion means for depositing said stack with said stack removal means; the improvement comprising:

at least one roll of said nip cooperative provided with depressed relief to the circumferential periphery thereof whereby said stack may be drawn between said depressed relief portion and another roll of said nip cooperative, when said one roll is stationary, said depressed relief forming an abutment surface to align the leading edges of said panels during said stack accumulation.

7. The combination as described by claim 6 wherein said delivery means comprises a first panel transfer plane and said stacking station comprises a second panel transfer plane, said first and second panel transfer planes intersecting at an obtuse angle, said stacking station having a length dimension extending along said second panel plane between said one roll abutment surface to a point beyond said first and second transfer plane intersection whereby each panel added to an accumulating stack is inserted at the interface between said second transfer plane and the previously added panel face.

8. The combination as described by claim 7 wherein said other roll of said nip cooperative is continuously rotating.

9. The combination as described by claim 8 wherein rotational power delivered to said one roll of said nip cooperative is intermittently transmitted by selectively engaged single revolution clutch means.

10. The combination as described by claim 9 wherein engagement of said single revolution clutch means is prompted by a signal emitted by said counting means.