US3698707A

US3698707A - Sheet stacker and control stack removing means

Info

Publication number: US3698707A
Application number: US93747A
Authority: US
Inventors: Raymond L R Lucas
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-12-22
Filing date: 1970-11-30
Publication date: 1972-10-17
Anticipated expiration: 1989-10-17
Also published as: FR2071242A6; DE2062781A1

Abstract

A sheet conveyor is provided for depositing sheets onto a stack with the conveyor discharging end being moved progressively upward as the stack height increases with a stop plate being positioned forward of the discharge end of the conveyor and mounted on adjustable horizontally movable arms for adjustment to the size of the sheet being stacked with the sheets being deposited on a reversible power driven conveyor and safety contact switch means being provided on the sheet conveyor and with control switch means on the discharge side of the stop plate for enabling a close spacing of successively formed sheet stacks.

Description

United States Patent Lucas 154] SHEET STACKER AND CONTROL STACK REMOVING MEANS [72] inventor: Raymond L. R. Lucas, Avenue de la Republique, Prechac, France [22] Filed: Nov. 30, 1970 [21] App1.No.: 93,747

[30] Foreign Application Priority Data Dec. 22, 1969 France ..6944504 [52 us. Cl. ..27l/68, 2 14/6 0 [51] Int. Cl. ..B65h 29/50 [58] Field of Search ..27l/68, 86; 214/6 G [56] References Cited UNITED STATES PATENTS 3,321,202 5/1967 Martin ..27l/68 1,389,244 8/1921 Free ..27l/68 [451 Oct. 17,1972

3,549,144 12/1970 Lucas ..271/68 Primary Examiner-Evon C. Blunk Assistant Examiner-Bruce H. Stoner, Jr.

Attorney-Mason, Fenwick & Lawrence [5 7] ABSTRACT A sheet conveyor is provided for depositing sheets onto a stack with the conveyor discharging end being moved progressively upward as the stack height increases with a stop plate being positioned forward of the discharge end of the conveyor and mounted on adjustable horizontally movable arms for adjustment to the size of the sheet being stacked with the sheets being deposited on a reversible power driven conveyor and safety contact switch means being provided on the sheet conveyor and with control switch means on the discharge side of the stop plate for enabling a close spacing of successively formed sheet stacks.

6 Claims, 8 Drawing Figures PATENTED 17W? 3,698,707

sum 1 BF 3 INVENTOR QAYMQND L-E. Lucas ATTORNEYS PATENTEUBN 1 1 3.698.707

SHEU 2 BF 3 ilg-a- RAYMOND R. Lucas Mus im f ATTORNEYS SHEET STACKER AND CONTROL STACK REMOVING MEANS The subject invention is in the field of stacking machines and is specifically directed to improvements in stop or gauge plates employed for forming vertical stacks of planar members such as sheets formed of corrugated cardboard, fiberboard or the like. Specifically, the invention is directed to a new and improved adjustable guide and support means for a stop plate situated in front of the discharge end of a sheet feeding conveyor belt head. The stop or abutment plate is held in a vertical position by two horizontal arms which are horizontally adjustable in accordance with the size of the sheets to be stacked. These horizontal arms slide in supports pivotable about the axis of the stacker head of the conveyor and are held in parallel horizontal arrangement by a parallelogram linkage of which one side of which is the frame of the machine.

Prior experience has shown that previously known stop devices of the type rigidly attached to horizontal arms sliding in and extending from the conveyor frame element which supports the sheet conveyor belt are difficult to operate and frequently provide a source of danger to the operator who must, during the formation of a stack, occasionally reach to the center of the stack in order to straighten out the pile or to remove small particles of trash, clippings, chips or the like.

Additionally, the prior known rigid systems employ horizontal arms and a vertical abutment or stop plate fixed at the end of the arms is frequently subject to malfunction or damage since a descending movement of the stop plate from an upper position to a lower position can cause the plate to engage misplaced stacks or other items and consequently inflict damage upon the engaged items or to the stacker assembly itself. This fact has resulted in inconvenience and inefficiency of operation due to a variety of other factors such as the desirability of providing completed piles travelling in fixed relationship on an outfeed conveyor rather than in irregular relationship. Consequently, efficiency frequently suffers due to the substantial time required for removing successive stacks from the stacker.

The instant invention constitutes a modification of the prior known systems and enables the obtainment of considerable advantage thereover both in technical ease of operation and economy of operation, not to mention the provision of greater safety for the operator of the machine.

Specifically, the subject invention employs a pair of horizontal laterally spaced cantilever arms for supporting the vertical stop plate with the horizontal arms being positioned very near the longitudinal axis of the stacking conveyor in a slide bearing type support provided with means for guiding the arms and for adjustably positioning the arms in relation to the sheets being stacked.

It should be noted that the previously known arrangement of support arms and stopplates have been in the form of an integral construction with the plate extending integrally or in a fixed manner from the end of the arms. The present invention, on the other hand, provides support for the stop plate in a slide bearing system arranged at the end of the arms with the plate being normally held at the lower end of the slide by virtue of the force of gravity but being movable upward if an upward force should be applied to it. During the return movement of the stacker head from its upper position to its lower position following the completion of a stack, any obstacle which is engaged by the lower edge of the stop plate is not damaged since the stop plate merely moves upwardly within the slide in which it is retained. Such upward movement of the plate with respect to its supporting slide bearing serves to actuate an electric switch connected to the control for the motor employed in lowering the discharge end of the conveyor for deactivating the motor. The operator can then remove the object with which the stop plate is engaged in order to reactivate the motor and continue downward movement of the discharge end of the conveyor. Consequently, the instant invention provides a safety feature which avoids damage to articles positioned beneath the descending stop plate and also serves to avoid unfortunate injuries to the operator of the device.

Additionally, the subject invention provides means whereby the adjacent stacks deposited on a stack receiving and removing belt are automatically removed in response to the sheet conveyors reaching its upper limit of travel upon completion of each stack. This discharge movement of the completed stack is calculated to produce a suitable arrangement and spacing of the successive stacks on the belt and also permits a free descent of the stacker head following the completion of the stack in order to initiate the formation of the next stack. Arrival of the discharge end of the stacker conveyor at its lowermost position serves to activate an electrical switch which initiates operation of the stack receiving and removing belt in a reverse direction to return the just completed stack against the outer face of the stop plate. The stop plate is, in turn, equipped with an electric switch on its outer face which stops the return movement of the stack receiving and removing belt. Consequently, the next stack to be formed will be separated from the last formed stack solely by the thickness of the stop plate.

Another feature of the present invention is that the horizontal stop plate support arms form a unique undeformable mechanical unit independent of the stop plate. The unit consists of the horizontal arms which are positioned closely together and which are joined at one end by a slide which provides support for the stop plate and at its other end by a cross piece. The axis of this mechanical system is situated in the longitudinal plane of the stacker conveyor. Consequently, lateral twisting forces from the arms to the sheet conveyor will be minimized.

Another significant feature of the present invention is the employment of a casing type support at the center of a crosspiece that links the two horizontal supports for the stop plate. A number of rollers some of which are mounted for rotation about a vertical axis and the other of which are mounted for rotation about a horizontal axis provide support for the horizontal arms. The mechanical system for supporting the horizontal arms supporting the stop plate enables reciprocal adjustment in a horizontal plane of the arms by virtue of the arms being supported by the rollers. Consequently, the support system provides an easily adjustable positioning of the stop plate a given distance away from the discharge end of the sheet conveyor for enabling the stacking of various size sheets.

A better understanding of the subject invention will be enabled by the following description with reference to the drawings in which:

FIG. 1 is a side elevational view of the preferred embodiment of the invention;

FIG. 2 is a plan view of the preferred embodiment with some parts not illustrated for the sake of clarity;

FIG. 3-A is a side elevational view illustrating a stack being formed on the receiving and removing conveyor;

FIG. 3B is a side elevational view similar to FIG. 3-A illustrating a completed stack prior to removal of the stack from the stacking station;

FIG. 3-C is a side elevational view illustrating the position of the completed stack following initial removal of the stack from the stacking position;

FIG. 3-D is a side elevational view illustrating return movement of the completed stack to a position adjacent the outside of the stop plate;

FIG. 3-E is a side elevational view illustrating the formation of a second stack which is being formed adjacent the first stack; and

FIG. 4 is a schematic diagram of electrical circuitry usable for controlling the stacking components.

A sheet feeding stacking conveyor supported by two (only one of which is shown in FIG. 1) conveyor supporting side frame members I is provided with a head roller 2 which supports an endless sheet feed discharge belt 3, the upper flight of which is moving to the left in FIG. 1 and which feeds sheets to be stacked to a stacking or depositing station generally designated D. A guide support frame 4 is positioned on each side of the conveyor frame elements 1 (only one of the guide support frame elements 4 is illustrated in FIG. 1). Each of the guide support frame members 4 is pivotally connected for pivotal movement about the axis of roller 2 and is maintained in a vertical orientation by virtue of a rocking lever 5 connected to the frame 4 on one end and connected on its other end to the main machine frame F of the stacker (FIG. 3-A). There is parallelogram relationship between the

elements

5, 4, 1 and the main frame F to which elements 1 and 5 are pivotally connected so that the guide support frames 4 are maintained in vertical orientation at all times.

A tubular crosspiece 6 is fixedly attached to the upper ends of the support frames 4 and extends laterally in relation to the conveyor belt 3 as is clearly shown in FIG. 2 of the drawings. First and second vertical side plates 7 and 7-A are welded to the transversely extending support member 6. A pair of horizontal plates 8 and 9 (FIGS. 1 and 2) are connected to the side plates 7 and 7-A and horizontal arms 10 and 10-A (FIG. 2) are mounted for axial horizontal movement between the plates 8 and 9 by means of horizontal axis rollers 18 and vertical axis rollers 19 respectively supported on plates 7, 7-A and 9.

Additionally, the horizontal arms 10 and l0-A are connected to each other by means of a crosspiece 11 adjacent their rearmost ends (the right as viewed in the drawings) and are connected on their other ends to a vertically oriented slide bar 12. Slide bar 12 is supported by side plates 13 and 13-A which are attached to the side of the horizontal arms 10 and 10-A as best shown in FIG. 2. Each of the side plates 13 and 13-A carries a set of four rollers 14 which are mounted for rotation on horizontal arms perpendicular to the axes ofarms l0 and 10-A.

A stop or gauge plate 15 is mounted for vertical movement by virtue of a pair of U-shaped channel members 17 and 17-A which are attached to extend from the deposit station facing side of plate 15 toward the right as viewed in FIG. 2 and have a rearmost flange receivable within the respective rollers 14 on each side of the horizontal arms 10 and 10-A. Consequently, the U-shaped channel members 17 and 17-A are capable of controlled vertical movement along with their attached gauge or stop plate 15. Additionally, the stop plate 15 is provided with a horizontally extending rigid base member 16 extending across its entire width which provides reinforcement for the plate.

A horizontal guide and locking rod 20 extends parallel to the horizontal arms 10 and 10-A between the crosspiece 11 and the vertical slide bar 12 and supports a split ring type clamp member 21 which can be adjustably positioned at any point along the length of the rod 20 and which can be clamped thereto in an obvious manner. The adjustment of the rod 20 with respect to the horizontal plate 8, etc., serves to position the stop plate 15 at a desired horizontal distance in front of the discharge end of conveyor 3 in accordance with the size of sheets to be discharged from the conveyor 3. It should be noted that the rod 20 is fixedly attached to both the crosspiece 11 and the vertical slide bar 12. A lever 21' is operably mounted on split ring clamp 21 for enabling loosening of the clamping action of the clamp to rod 20 to permit adjustment of the position of clamp 20 on the rod and subsequent tightening of the clamping member to retain same in a desired adjusted position on the rod 20.

An electric switch 22 is connected to the upper portion of the vertical slide bar 12 (FIG. 1) for permitting operation of the stacking mechanism. A horizontally extending switch actuating flange 17-B extends over switch member 22 and normally rests on a switch actuating plunger or arm of the switch for closing the contacts of the switch. However, since flange 17-8 is connected to the channel members 17 and 17-A, along with the stop plate 15, vertical upward movement of the stop plate 15 with respect to switch 22 serves to permit the contacts of switch 22 to open. A second electric switch 23 is mounted with its actuator arm 23' on the outer or downstream face of the stop plate 15 for controlling the movement of a completed pile of sheets in a manner to be discussed in' detail hereinafter. Switch 23 is for interrupting electric current to a drive motor 60 of a stack receiving and removing conveyor 30 which conveys the completed stacks away from the stacking station. The drive motor 60 of conveyor 30 is reversible for a purpose stated hereinafter and during a reverse operation the engagement of a completed stack with the switch arm 23 serves to open switch 23 to deactivate the motor to discontinue reverse movement of the stack to the right.

Additionally, an electric switch 24 attached to plate 8 is provided for initiating the operation of the stacker for the formation of a new stack. Switch 24 is controlled by a switch actuator plate 25 extending from the adjustable stop clamp member 21 mounted on rod 20. An adjustable spring bias stop member 26 carried by plate 8 is positioned on the side of plate 25 opposite switch 24 as shown in FIG. 2 to limit movement of plate 8 with respect to actuator plate 25.

Additionally, pressure responsive switch

actuator elements

27, 28 and 29 are provided for deactivating the motor (not shown) for driving the conveyor frames 1 downwardly during descent of the conveyor frame in the event that any of these switch actuator elements engages in immovable object such as the operators hand, a misplaced stack or other improperly positioned member.

It should be understood that

actuator elements

27, 28 and 29 can be conventional pressure responsive planar pad type switch members or can be switch actuator lever arms if such should be desired. Planar type switch actuators of the type contemplated are frequently employed for automatically opening doors or the like in response to the pressure of a person approaching such electrically controlled doors.

It can be seen that the adjustment of the stop member 21 and its associated finger lug 25 on bar 20 is determined in accordance with the size of the sheets to be stacked and the closing of the switch 24 serves to actuate the motor for providing pivotal movement of .frame 1 to initiate a slow upward movement of the discharge end of the conveyor (the end with roller 2, etc.) The conveyor is operated until the stack has reached a predetermined height. Following completion of a stack, lifting movement of the discharge head of the conveyor continues although no additional sheets are being fed by the conveyor 3 until the abutment or stop plate completely clears the completed stack so that the stack can be removed to the left by conveyor Electrical voltage is supplied by

main conductors

38, 40 and the parts are in the position shown in FIG. 3-A as a stack S1 is being formed as sheets are fed inwardly by the conveyor 3 against the stop plate 15 and deposited on the stack S1 supported on a pallet 69 on conveyor 30. The control and drive means for moving the discharge end of conveyor 3 gradually upward is preferably of the type shown in my copending application Ser. No. 743,419 U.S. Pat. No. 3,549,144, and continues to be operated following completion of the stack and is lifted above the top of stack S1 as illustrated in FIG. 3-B.

Following termination of the upward movement of plate 15, switch means CB2 of relay CB is closed by operation of timer T or manually for a predetermined period of time to operate the drive motor 60 for driving the stack receiving and removing conveyor to the left in the direction of the arrow shown in FIG. 3-C. Following termination of movement of the completed stack S1 to the left to the approximate position illustrated in FIG 3-C, a down relay R2 is actuated either manually or by timing control circuit T for initiating lowering movement of the discharge end of the conveyor 3 to lower the conveyor and the stop plate 15 to the position shown in FIG. 3-C.

Since stack S! has been moved to the left from the vicinity of the stop plate 15, there is no impediment to the lowering of stop plate 15. However, if the

switches

28, 29, etc., should engage an obstacle during the descent of the conveyor 3, the down relay R2 controlling the conveyor tilt motor (not shown) for effecting downward movement of the discharge end of conveyor 3 will be immediately deactivated to terminate such movement. Similarly, upon arrival of the discharge end of conveyor 3 at its lowermost position, the plate 15 engages the conveyor 30 and is moved upwardly to open switch 22 to terminate actuation of the down relay R2.

Following the arrival of the discharge end of the conveyor 3 in its lowermost stack initiating position shown in FIG. 3-C, a switch 61 is closed by timer T or manually for actuating a reverse drive conveyor relay CC to close contacts CC2 for an adequate period of time to operate motor in a reverse direction to cause the conveyor 30 to move to the right as shown in FIG. 3-D so that the completed stack S1 is moved rightwardly until it abuts against the left side of the stop plate 15. Engagement of stack S1 with the stop plate 15 immediately opens switch 23 to deactivate the reverse drive relay CC and consequently terminates reverse drive of conveyor 30 by motor 60. Moreover, engagement of the stack 51 with the plate 15 also serves to shift the plate 15 to the right sufficiently to close contacts 24 which consequently initiates another cycle of operation of the timer control circuit T. It should be understood that the

various switches

52, 54, 50, 61, etc., can be manually operated or automatically operated by controlled timer switch units in the schematically illustrated timer circuit T. Moreover, both manual and automatic operation can be provided in a manner obvious to those skilled in the art.

Following closure of switch 24, the feeding of sheets onto conveyor 3 is initiated by timer T along with the required closure of contacts 52 to start the upward movement of the discharge end of conveyor 3 by activation of an up relay R1 which makes the motor controlling the discharge head of the conveyor move the head upwardly as a second stack is being built. Consequently, a new stack S2 is begun as shown in FIG. 3-15 and the sheets continue to be fed until the stack S2 is completed. Following completion of stack S2, the discharge end of conveyor 3 continues to move upwardly in a previously discussed manner so that the lower edge of the plate 15 will be above the top of stack S2 at which time relay R1 is deactivated to stop upward movement of the conveyor 3. The stack receiving conveyor 30 is then activated to remove the stack to the left in the same manner as stack 81 was moved. The discharge end of the conveyor is again lowered following actuation of relay R2 and stack S2 is moved to the right to open switch contact 23 and close contacts 24 to initiate another cycle of operation.

Consequently, it will be seen that the subject inventive arrangement enables an optimum close spacing of the successively completed stacks on conveyor 30.

If, during the descent of the stacker head, an obstacle should engage the lower edge of the abutment or stop plate 15, the plate is pushed upwardly by virtue of its sliding movement enabled between the rollers 14 and electrical switch 22 is opened to deactivate relay R2 to consequently automatically break the power circuit to the motor for lifting and lowering the discharge head of conveyor 3 to consequently stop the descending movement of the discharge head.

I claim:

1. In a sheet stacker of the type having a pivotally mounted sheet conveyor belt with a discharge head for discharging sheets onto a stack receiving and removing conveyor and means for moving the conveyor discharge head in an arcuate path from a lowermost position to an uppermost position as the height of the stack being formed increases, the improvement comprising a vertical stop plate, two horizontal parallel arm members joined on each end to form a unitary construction mounted for axial movement in slide means attached to the discharge head, adjustable means for axially adjusting the position of said horizontal arms with respect to said discharge head for supporting said stop plate in adjustable positions in spaced horizontal relationship to the discharge head, said arm means extending adjacent the vertical longitudinal plane of the sheet conveyor in a horizontal plane and guide means comprising a series of rollers mounted adjacent the ends of said arms opposite said discharge conveyor supporting said stop plate by means of a U-shaped channel member connected to the stop plate and extending between the series of rollers for permitting limited movement of said stop plate relative to said horizontal arm means perpendicular to said horizontal arm means.

2. The invention of claim 1 additionally including safety switch means upon which means supporting said stop plate rests when said stop plate is in its lowermost position whereby vertical movement of said stop plate with respect to said switch means as would occur upon the engagement of the lower edge of said stop plate with an obstacle during lowering movement of the discharge head of said conveyor serves to deactivate saidsafety switch to stop the lowering movement of said discharge head.

3. The invention of claim 2 additionally including a stack side detecting switch means mounted on said stop plate for detecting a stack moved against the side of said abutment plate opposite said discharge head and a second switch mounted on means fixed to said horizontal arms for actuation upon bodily movement of said stop plate towards said discharge head for activating said conveyor pivoting motor to initiate a subsequent stacking cycle.

4. In a sheet stacker of the type having a pivotally mounted sheet conveyor belt with a discharge head for discharging sheets onto a stack receiving and removing conveyor driven by selectively operable reversible drive means, and means for moving the conveyor discharge head in an arcuate path from a lowermost position to an uppermost position as the height of the stack being formed increases, the improvement comprising two horizontal, parallel arm members connected to the discharge head of the conveyor, extending outwardly over said stack receiving and removing conveyor, guide means mounted on the outer ends of said arm members, said guide means supporting a stop plate normally maintained in a lower position on said guide means by gravity, but movable to an upper position with respect to said guide means and arm members, switch means positioned adjacent said stop plate actuated by movement of said stop plate to said upper position for terminating downward movement of said discharge head upon engagement of said stop means with any fixed object or with said stack receiving and removing conveyor means.

5. The invention of claim 4 wherein said arm means is supported on said discharge head for limited axial movement between a forward extended position and a retracted osition in which said stop plate is positioned closely a acent said discharge hea biassmg means for urging said stop plate and said arm means toward said extended position and switch means engageable with means connected to said arm means for actuation upon movement of said arm means and stop plate to said retracted position caused by engagement of a completed stack with the outer surface of said stop plate when said stack receiving and removing conveyor moves a stack against said outer surface of said stop plate for initiating a new stacking cycle in which a second stack will be provided adjacent said first stack but spaced therefrom by the width of said stop plate.

6. A method of stacking sheets with a stacker of the type having a pivotally mounted sheet conveyor belt with a discharge head for discharging sheets at a stacking station against a stop plate mounted on the discharge head onto a stack receiving and removing conveyor driven by reversible drive means, said method comprising the steps of:

forming a first stack as said discharge head moves upwardly while continuously feeding sheets forming said stack;

discontinuing the feed of sheets from said discharge head when said first stack reaches a desired height while said discharge head continues to move upwardly;

discontinuing upward movement of the discharge head when the lowermost portion of the stop plate rises above the top of the first stack;

actuating said stack receiving conveyor in a forward direction to remove the first stack from the

Claims

2. The invention of claim 1 additionally including safety switch means upon which means supporting said stop plate rests when said stop plate is in its lowermost position whereby vertical movement of said stop plate with respect to said switch means as would occur upon the engagement of the lower edge of said stop plate with an obstacle during lowering movement of the discharge head of said conveyor serves to deactivate said safety switch to stop the lowering movement of said discharge head.

5. The invention of claim 4 wherein said arm means is supported on said discharge head for limited axial movement between a forward extended position and a retracted position in which said stop plate is positioned closely adjacent said discharge head, biassing means for urging said stop plate and said arm means toward said extended position and switch means engageable with means connected to said arm means for actuation upon movement of said arm means and stop plate to said retracted position caused by engagement of a completed stack with the outer surface of said stop plate when said stack receiving and removing conveyor moves a stack against said outer surface of said stop plate for initiating a new stacking cycle in which a second stack will be provided adjacent said first stack but spaced therefrom by the width of said stop plate.

6. A method of stacking sheets with a stacker of the type having a pivotally mounted sheet conveyor belt with a discharge head for discharging sheets at a stacking station against a stop plate mounted on the discharge head onto a stack receiving and removing conveyor driven by reversible drive means, said method comprising the steps of: forming a first stack as said discharge head moves upwardly while continuously feeding sheets forming said stack; discontinuing the feed of sheets from said discharge head when said first stack reaches a desired height while said discharge head continues to move upwardly; discontinuing upward movement of the discharge head when the lowermost portion of the stop plate rises above the top of the first stack; actuating said stack receiving conveyor in a forward direction to remove the first stack from the stacking station; lowering the discharge head to position the stop plate adjacent the stack receiving conveyor; operating said stack receiving conveyor in a reverse direction to return the first stack to a position adjacent the stacking station engaging the downstream side of the stop plate and initiating the formation of a second stack in the same manner as the first stack whereby the first and second stacks will be closely spaced a distance only slightly greater than the thickness of the stop plate.