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METHOD AND APPARATUS FOR FEEDING SHEET MATERIAL INTO A HOPPER
BACKGROUND OF THE INVENTION
The invention relates to a method and apparatus for delivering sheet material into a hopper and for positioning the sheets material into an even stack within the hopper. More in particular, the invention includes a method and apparatus for maintaining a stack of substantially predetermined size in the hopper of a machine for advancing the sheet material, one unit at a time, to another machine operation. By way of example, the sheet material to be positioned within the hopper can comprise groups of signatures of the type which make up a magazine or sections of a newspaper such as the main section. The invention can be used in conjunction with a hopper for feeding sheets of material to a book trimmer, a cover feeder of a binder, a newspaper stuffing machine, a mailing machine or a labeling machine.
In the gathering of the signatures which make up a book such as a magazine or in the assembly of a newspaper by a stuffing machine, it is necessary to maintain a supply of the sheet material in each hopper. Experience has shown that the loading of bundles or stacks of signatures into a hopper, all at once, in order to maintain some reference level of supply therein usually interferes with the proper operation of the gatherer removing the signatures from the bottom portion of the hopper. The reason why the delivery of a large number of signatures into the hopper at one time becomes a problem is that the mass of added signatures prevents the signatures from assuming the correct positions within the hopper. Furthermore, the delivery of a mass of signatures at one time means an instantaneous increase of force applied to the signatures already in the hopper. The increase in force can interfere with the removal of the bottommost signature in the hopper.
Experience has further shown that even if signatures are delivered to a hopper on an individual basis such as by hand or by a flow issuing from a conveyor, unsatisfactory operation can result if the signatures are not correctly oriented within the hopper. With a lack of proper orientation it becomes inevitable that the gatherer mechanism for sequentially removing the bottommost signature will periodically operate in an incorrect manner with the result that a "miss" occurs or a "double" is delivered.
Thus it can be seen that heretofore there has been a problem resulting from both the manner by which signatures have been delivered to a hopper and in the manner by which attempts have been made to position the signatures correctly within the hopper.
SUMMARY OF THE INVENTION
The invention provides a method and apparatus for feeding signatures in bursts to a hopper from a supply of signatures in order to prevent the sudden placing of a mass of signatures in order to prevent the sudden placing of a mass of signatures upon those already in the hopper and to enable the hopper to position the signatures in the burst correctly within the hopper. An apparatus constructed in accordance with one embodiment of the invention senses the lowering of the stack of signatures within the hopper beneath a predetermined size of stack. The output signal from the sensing
of the presence of a low level within the hopper activates a conveyor to deliver a stream of signatures in shingled form to the hopper. In accordance with the invention the operation of the conveyor is interrupted to
5 form bursts of operation having a predetermined duration and a predetermined period between successive bursts. A level switch within the hopper is actuated whenever the stack of signatures within the hopper falls below a minimum level. The signal from the level
10 switch controls a timer which has a predetermined duty cycle of "on" and "off periods. In turn, the timer during its "on" period of operation activates the conveyor to deliver signatures to the hopper in a burst having a
j 5 time duration which is a function of the "on" period of operation of the timer. The delivery of one or more bursts of signatures into the hopper actuates the level switch and terminates the operation of the timer and also the infeed conveyor. The cycle is repeated when
20 ever the level of signatures within the hopper falls below the predetermined level at which the sensing switch is actuated.
The invention further provides a method and apparatus for positioning the signatures of the bursts of
25 signatures within the hopper. One or more joggers each forming a wall portion of the hopper strike an edge portion of the signatures within the burst of signatures and cause rapid movement of each signature within the hopper as each signature descends upon the supply of
30 signatures already in the hopper. In an embodiment of the jogger construction, blasts of gas such as compressed air are used to enable the signatures to move relative to the ones adjacent thereto by minimizing the contact and friction between adjacent signatures. Thus
35 the blasts of compressed air enable the joggers to force the signatures into their proper position within the hopper.
In addition, the invention provides a method and ap
40 paratus for placing bundles or stacks of signatures onto the conveyor which delivers the signatures to the hopper in accordance with the invention. A supporting surface is pivotally mounted adjacent to the end portion of the conveyor opposite the end portion thereof
45 which delivers the signatures to the hopper. The supporting surface has an operable position in which the plane of the supporting surface is in alignment with and substantially coplanar with the surface of the conveyor. In the retracted position of the supporting member it
50 extends downwardly from the end portion of the end feed conveyor. With this construction the individual operating the machine can conveniently place a bundle or stack of signatures upon the supporting surface in its retracted position adjacent to the flow of the plant in
55 which the machine is installed. Subsequently the individual can elevate the pivotally mounted supporting surface in order to position the bundle or stack of material for transfer directly onto the infeed conveyor.
60 BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the apparatus of the invention which operate in accordance with the method of the invention are shown in the accompanying drawings in 65 which:
FIG. 1 is a side elevational view of an embodiment of the invention showing the device for delivering signatures to a conveyor system, the conveyor system and its
drives, and the hopper to which the signatures are to be delivered;
FIG. 2 is a plan view of the embodiment of FIG. 1;
FIG. 3 is a fragmentary vertical section view of a hopper having a jogger in accordance with the invention;
FIG. 4 is a fragmentary vertical section view of a drive for moving the jogger shown in FIG. 3 with a swinging motion;
FIG. 5 is a fragmentary plan view of the hopper including the jogger as shown in FIG. 3;
FIG. 6 is a fragmentary side elevational view of another embodiment of the hopper of the invention showing both the side jogger and the end jogger;
FIG. 7 is a fragmentary vertical section view taken along the line 7—7 in FIG. 6 and showing the drive to the side jogger and end jogger of the hopper; and
FIG. 8 is a schematic representation of the control circuit for producing the delivery of bursts of signatures by the conveyor.
DESCRIPTION OF THE PREFERRED
The machine of the invention as shown in FIGS. 1 and 2 comprises hopper feeder 10 which is adapted to deliver sheet material such as signatures or sections of newspapers 11 to hopper 12 from which the signatures or newspapers are delivered to another machine. In the embodiment of FIG. 1 hopper 12 delivers newspapers to the pockets 13 of a newspaper stuffing machine 14. Thus for example, after delivery of newspapers 11 into pocket 13, the newspapers are disposed with the fold of the newspaper adjacent to the bottom portion of a pocket with the result that the newspaper section assumes a V-shaped form into which inserts may be placed by the stuffing machine.
The hopper feeder is mounted upon frame 15 which is supported by rollers 16 which enable the hopper feeder to be moved with respect to the hopper whenever access must be had to the hopper for service or the like. The frame of the machine supports table 17 across which extends a first conveyor 18 which can be an endless belt conveyor having one or a plurality of conveyor belts. Table 17 provides a surface upon which bundles or stacks of newspapers can be placed for subsequent advancement by the hopper feeder toward hopper 12.
To facilitate the placement of stacks 19 of newspapers upon table 17, the hopper feeder can be provided with carrier 20 which is pivotally and slidably mounted with respect to table 17. In order to load stack 19 of newspapers onto table 17, the machine operator places the stack upon bracket 20a of carrier 20. By way of example, newspapers 11 can be placed upon bracket 20a with the folded portion extending from right-to-left across each page of the section in a vertical position and extending into the drawing as viewed in FIG. 1. The operator would then swing carrier 20 upwardly about its pivot 206 until the carrier is in a substantially horizontal position in which the upper surface of the carrier would be coplanar with the upper surface of table 17 and the upper reaches of the first conveyor. At this point the operator can slide the pivot 20b along tracks 21 within table 17 until stack 19 of the newspaper sections is transferred onto the first con
veyor. Thus it can be seen that carrier 20 eliminates the need for the operator to lift the stacks to the height of table 17 since the carrier supports a good portion of the weight of the stack as it is elevated into its operative
5 position shown by dash lines in FIG. 1. In addition, the pivotal mounting of the carrier reduces the overall length of the machine as compared to the same machine having a fixed infeed table in advance of conveyor 18. Stack 19 on table 17 can have the folded por
10 tion of each of the sections of the newspaper contiguous with plate or back wall 22 extending vertically along the length of the machine. Downstream of first conveyor 18 there is disposed
(5 second conveyor 23, the upper reach of which is substantially coplanar with that of conveyor 18. The downstream end portion of the second conveyor is adjacent to the entrance portion of third conveyor 24 which is inclined upwardly in the direction of hopper
20 12. The final or fourth conveyor 25 of the hopper feeder extends in a substantially horizontal direction adjacent to the entrance portion of the hopper. As in the case of the first conveyor, the remaining conveyors can be of the endless belt type.
25 Each of the conveyors is provided with its own drive extending from a clutch which connects the drive to a source of power such as an electric motor. Thus, first conveyor 18 includes drive chain 18a coupling the conveyor to clutch 18b which in turn is connected to motor
30 18c. Second conveyor 23 is provided with chain 23a, clutch 23b and motor 23c. Chain 24a, clutch 24b and motor 24c provide power for conveyor 24. In a similar manner, chain 25a, clutch 25b and motor 25c drive the fourth conveyor 25.
35 In order to control the hopper feeder to provide bursts of signatures or newspaper sections to hopper 12, it is necessary to maintain a supply of newspapers moving from the first conveyor to the second conveyor
4Q and extending along the third conveyor. On the third conveyor the stacks of newspapers can topple to the right as viewed in FIG. 1 as the bottommost newspaper section begins to travel upwardly along conveyor 24. In order to sense the presence or absence of the
45 newspapers along the first three conveyors, sensing devices 26, 27 and 28 such as sensitive electrical switches are disposed adjacent to the first, second and third conveyors, respectively. Thus, as is shown in FIGS. 1 and 2, switch 26 is disposed adjacent to the
50 downstream end portion of the first conveyor, switch 27 is disposed adjacent to the elevated downstream portion of the second conveyor, and switch 28 is disposed adjacent to the downstream portion of the third conveyor. In this way, switches 26 and 27 can
55 sense the passage of the last newspaper of a stack with respect to the conveyors adjacent thereto.
As shown in FIGS. 1 and 2, hopper 12 includes bottom plate 12a, side plates 12b and end plates 12c and 12d which form an enclosure into which the newspaper
60 sections are to be delivered. Hopper 12 is supported by frame members 12e with respect to stuffing machine 14. A gatherer mechanism (not shown) removes the lowermost signature disposed upon plate 12a through a
65 slot between the edge portion of plate 12a and the lower edge portion adjacent thereto of plate 12b and advances the lowermost newspaper section along guides 29 into pocket 13 of the stuffing machine. In
operation it is necessary to maintain a predetermined size of stack of newspaper sections with the hopper as shown in FIG. 1 and, consequently, it is necessary to sense the presence of the predetermined size of stack of newspaper sections. Therefore, within the hopper there is provided sensing switch 30 which has arm 31 extending through one of the side or end plates of the hopper at the position of the top of the desired predetermined size of stack of newspaper sections within the hopper.
When the level of newspapers within hopper 12 is below the low limit, the contacts of normally closed switch 30 are in the closed position (FIG. 8). In the normally closed position of switch 30, relay 32 is energized. Switch 28 which is mounted adjacent to the elevated downstream position of third conveyor 24 is a normally closed switch and therefore when no newspapers are positioned upon switch 28, its contacts are closed. Switch 28 is connected to the winding of relay 33. As a result, the relay is only deenergized when the normally closed contacts of switch 28 are caused to be opened by the presence of newspapers along third conveyor 24 and overlying switch 28. Contacts 33a of relay 33 are normally closed and therefore these contacts are closed whenever newspaper sections are present along the third conveyor. Contacts 34 are part of a relay (not shown) for selectively energizing the entire machine and are closed whenever the system of the invention is to be operated.
Timer 35 which is connected in series with contacts 33a and 34, is adapted to produce predetermined periods of the opening and closing of timer contacts 35a. When the timer is deenergized by the opening of contacts 33a, contacts 35a of the timer rest in the opened condition. Timer 35 is adjustable for obtaining predetermined periods of the "on time" of contacts 35a and the "off time" of contacts 35a. By way of example, both the "off time" and the "on time" can be adjusted over a range extending from approximately 0.2 to 10 seconds. Further, by way of example, a device which can be used as timer 35 is manufactured by Eagle Signal, a division of Gulf and Western Industries, Inc. of Davenport, Iowa and is described as "Transistorized Timers, CG 100 Series."
Since hopper level switch 30 is normally closed when there is an insufficient level of newspaper sections within the hopper, it can be seen that it enables timer contacts 35a to energize relay 32 whenever the hopper level switch is closed. In turn, relay 32 when energized closes the normally open contacts 32a-d which are connected to electric clutches 18b, 23b, 24b, and 25b, respectively. Consequently, the energizing of relay 32 enables the clutches to engage each of motors 18a, 23a, 24a, and 25a and thereby enable each of the four conveyors to be operated. As shown in FIG. 8, switches 26 and 27 control latching relays 18c which control contact 18d connected between contact 32a and clutch
If there are no newspaper sections disposed along the third conveyor 24, then the contacts of normally closed switch 28 are closed, thereby energizing relay 33. In turn the energizing of relay 33 causes its normally closed contacts 33a to open and thereby interrupt the circuit to timer 35. At the same time, the energizing of relay 33 causes the closing of normally open contacts 33b and as a result a circuit is connected to relay 32
through contacts 33b any time hopper level switch 30 is closed. In this way it can be seen that timer 35 is eliminated from the control circuit so long as newspaper sections are not available on conveyor 24. 5 In a condition where there is an insufficient level of newspaper sections in hopper 12, relay 32 is energized and in turn contacts 32a-d are energized. In this initial condition, contact 18a* is closed. With first conveyor 18 and second conveyor 23 operating, a stack 19 of 10 newspaper sections can be advanced from the first conveyor over switch 26 to the second conveyor. First conveyor 18 continues to operate after the passage of the first bundle 19 across switch 26 due to the holding ac15 tion of latching relays 18a" until the second bundle arrives at switch 26. The latching relays are then actuated by the operation of switch 26 to open switch contacts 18d and cause the disengagement of clutch 18£> to motor 18a. As a result, the first conveyor ceases to 20 operate and holds the second bundle adjacent to the entrance to the second conveyor.
With third conveyor 24 and fourth conveyor 25 operating, the first bundle of newspapers are carried away from the second conveyor. As soon as the last 25 newspaper in the first bundle has passed beyond switch 27, the operation of switch 27 actuates latching relays 18c to close switch contacts 18d and cause clutch 18f> of the first conveyor to be again engaged. As a result, motor 18a drives the conveyor and advances the 30 second bundle of newspapers. The cycle continues as the third bundle of newspapers arrives at switch 26. The operation of switch 26 actuates latching relays 18c to open contacts 18d and cause the termination of the drive of motor 18a to the first conveyor. In this way it 35 can be seen that a supply of bundles of newspapers to the third conveyor is maintained as long as the third and fourth conveyors are delivering newspapers to the hopper.
^ As long as the hopper level switch is closed due to an insufficient height of newspapers within the hopper, relay 32 is cycled on and off by timer 35. As a result, the cycling of the third and fourth conveyors causes the newspapers to be delivered in bursts of predetermined 45 duration and with predetermined time gaps therebetween. Consequently, the hopper receives the newspapers in bursts rather than in a continuous stream.
Experience has shown that many of the problems re50 lated to the handling of heavy signatures such as the sections of a newspaper in a hopper which is delivering signatures to a high speed gatherer are eliminated by the method of feeding the hopper in bursts rather than continuously. As is described hereinafter, the hopper 55 can be adapted to "work" a limited number of incoming signatures in a burst by striking an edge portion of each of the signatures because of the limited mass of signatures and the fact that the limited number do not press with excessive force upon one another and upon 60 the signatures already in the hopper. In contradistinction the delivery of a continuous flow of signatures, especially where they are of a heavy nature, presents an excessive mass for the hopper to work upon and in ad65 dition causes the signatures to bear with excessive friction and pressure upon one another. Since the timer 35 can be conveniently adjusted for the duration of the "on time" and "off time" of contacts 35a, the bursts