GB2048831A

GB2048831A - Drop sheet stacker

Info

Publication number: GB2048831A
Application number: GB8013631A
Authority: GB
Original assignee: SITMA Societa Italiana Macchine Automatiche SpA
Current assignee: SITMA Societa Italiana Macchine Automatiche SpA
Priority date: 1979-04-24
Filing date: 1980-04-24
Publication date: 1980-12-17
Also published as: DE3015841A1; DE3015841C2; IT1112722B; IT7922143A0; SE8003021L; SE450375B; NL189082B; FR2454990B1; NL8002338A; FR2454990A1; GB2048831B

Abstract

A stacking unit comprises a conveyor 2 for feeding one article 3 at a time, a swingable pair of upper trays 7 for dropping one article 3 at a time into a collecting and stacking site 58 until a preselected number of items is reached, and a pair of lower trays 33 for temporarily supporting the articles being dropped and counted when an ejector 45 finally ejects to a delivery conveyor 47 a completed package containing the required number of articles. <IMAGE>

Description

SPECIFICATION Stacker for articles of flattened outline such as newspapers and magazines This invention relates to a stacker for articles of flattened outline, such as newspapers and magazines.

In many cases, the necessity arises of combining articles of flattened outline into units of stacked articles in a preselected number, the latter being either constant or variable from a package to another. This is true, more particularly, for the delivery of newspapers and magazines to beshifted in packages of any desired number towards the several piaces of delivery.

Stackers adapted to such use are already known, but they are generally impaired by the defect of being both constructionally and functionally intricate, bulky and expensive. What is desired is a stacker for articles of flattened outline, such as newspapers and magazines more particularly, which is simple, not too bulky, and comparatively economical.

The present invention provides a stacker which comprises an input feeder adapted to feed one article at a time, an end-of-stroke stopping abutment for said article, a couple of upper trays which are displaced for each fed-in article from a position wherein said article is supported to a position of clearance adapted to permit the free fall of such article into an underlying collection site for stacking them and form a package of stacked articles, ejectors means controllable to effect the ejection of said package of articles from said collection and stacking site when the number of stacked articles attains a preselected value, and a couple of lower trays located between said upper trays and said collecting and stacking site and controllable to be momentarily shifted from an at rest position to a position of collection and momentary support of the next article allowed to fall by the upper trays concurrently with each active stroke of said ejector means.

It is apparent that the stacker, which is entirely based on the retaining and subsequent free fall of the articles into a collection site whence they are subsequently ejected in packages containing a desired number of articles, is both structurally and functionally very simple, so that, generally speaking, it is comparatively cheap. Also, the bulk can appropriately be confined within reduced limits, inasmuch as the articles do not receive any motions other than the free fall, so that the bulk can be made only just greater than the bulk of the articles.

The invention will be described further, by way of example, with reference to the accompanying drawings, wherein: Fig. 1 shows a stacker in top plan view; Fig. 2 shows a cross-sectional view of the stacker taken along the direction of feeding of the article, i.e. along the line Il-Il of Fig. 1; Fig. 3 shows the stacker in cross-sectional view taken along the line Ill-Ill of Figures 1 and 2; Figures 4, 5 and 6 are cross-sectional views akin to that of Fig. 3, but referred to different stages of operation of the stacker; Figures 7 and 8 are plan views of the collecting and stacking site of the articles, and of the relevant ejector means, shown in two different stages of the operation; Fig. 9 shows the stacker in cross-sectional view, taken along the line IX-IX of Fig. 1 ; and Fig. 10 shows a block diagram of a possible control unit for a stack of the kind referred to above.

The stacker shown in the drawings comprises a base framing 1, in the top section of which (Fig. 1) there are fed by a conveyor belt 2, one at a time, the articles 3 to be stacked. A photoelectric cell 4, or any other kind of a sensor element (Fig. 1) is inserted in the route of the articles on the conveyor belt so as to detect the arrival of the articles in registry with the stacking unit.

Shortly past the outlet of the conveyor belt 2, a tray 5 is arranged, which is adjustably fastened at 6 to the base framing 1 and acts as an end-ofstroke stopping abutment for the articles which are sequentially fed in (Figs. 1 and 2).

Between the outlet of the conveyor belt 2 and the tray 5 (end of stroke) there are, laterally arranged, two upper trays 7, both in the shape of an "L", which have the task of momentarily supporting the article as it is individually fed in, such article being also laterally retained by a couple of side edges 8 (Figs. 1-3). Each of the upper trays is supported for rotation at 9 by a journal 10 which can be adjusted at 11 on the base framing 1 (Figs. 1 and 3), and can be rotated between the position of Fig. 3, adapted to support an individual article, and the clearance position shown in solid lines in Fig. 4, under the control of a connecting rod 1 2-crank 13 assembly: this assembly is connected by a telescopable bar 1 4 to a control arbor 15, either directly or via a belt drive transfer comprising two sheaves 16 and 17 and a belt 1 8 (Figs. 1 and 9). The arbor 15, in its turn, is alternately connected to and disjoined from an electric motor 19 via an electromagnetic clutch 20 and a belt drive comprising two sheaves 21 and 22 and a belt 23 (Figs. 1 and 9).

Via a similar drive-transfer unit, which comprises a sheave 24, an electromagnetic clutch 25, an arbor 26, a belt drive with two sheaves 27 and 28 and a belt 29, two telescopable bars 30 and two connecting rod 31-crank 32 assemblies (Figs. 1 to 3 and 9), the electric motor 1 9 referred to above is also capable of driving to rotation two lower trays 33, also shaped in the form of an "L", located beneath the upper trays 7 and having pivotal pins 34 borne by journals 10 along the same vertical line of the pivotal pins 9 of the trays 7 (Fig. 3). Also the lower trays 33 can be rotated between an at rest or clearance position (Fig. 3) and an active position (Figs. 5 and 6) wherein it is capable of collecting and retaining a possible article 3 allowed to fall by and from the upper trays 7.Two side edges 35 are similarly supported by the journal 10 on the same vertical line of the upper edges 8 (Fig. 7) for laterally holding the articles, whereas another fixed edge 36 is arranged paraliel of the fixed tray 5 (Fig. 2) to confine an appropriate fall hopper for the articles concerned.

Beneath the two couples of trays 7 and 33, a site 58 is provided for collecting and stacking the articles: said site comprises a conveyor belt 37 actuated by a motor 38 via a belt drive 39, four fixed bars for lateral confinement,40, and a couple of front-holding bars 41, each of which (Figs. 2, 3, 7 and 8) is borne by a lever 42 rotatable at 43 under the control of a pneumatic jack 44. The collecting and stacking site 58 is associated to an ejector plate 45, which is driven to translation from the at rest position of Fig. 7 to the ejection position of Fig. 8, by a pneumatic jack 46.

A belt conveyor 47, actuated by a motor 48 via a belt drive 49 is arranged at the outlet of the conveyor 37 to dump the articles 3 ganged in packages 50.

The stacker shown in the drawings, lastly, is completed by an electronic control unit, a possible block diagram for which is shown in Fig. 10.

Provision is made to that the input photoelectric cell 4-controls at the arrival of each article 3 on the conveyor 2, the energization of the electromagnetic clutch 20 with a delay that the delaying device 51 causes to correspond to the time which is necessary to that the article may reach the stopping tray 5, and for a time that a time 52 causes to correspond to one revolution of the mainshaft 1 5. The pulses from the photoelectric cell 4 are likewise delivered to the count-up input of a digital counter 53, which counts them and, as they attain a preselected value, initially preset and variable consistently with a predetermined programme, or variable according to information progressively fed into a generic presetting and control unit, 54, controls the actuation of the electromagnetic clutch 25 for a time that a timer 55 causes to correspond to one half revolution of the shaft 26. The counter 53, moreover, concurrently controls the timed energization of the motor 38 and the actuation of the pneumatic jacks 44 and 46 from the position of Fig. 7 to that of Fig. 8, whereas the reset of said jacks to their inoperative positions is controlled by an appropriate sensitive element 56 which is adapted to detect the end of the outward stroke of the ejector member 45. A second sensitive element 57, conversely, is capable of detecting the reset to the at rest position of the ejector member 45 and to control, then, via the timer 55, a fresh actuation of the electromagnetic clutch 35 for a time equal to half revolution of the driving shaft 26. 57 also controls the resetting of the counter 53.

The result is the following operation of the stacker shown in the drawings. While the motors 19 and 48 are regularly running in a continuous manner, the electromagnetic clutches 20 and 25 are de-energized, is that the arbors 1 5 and 26 are disjoined from the motor 1 9 and consequently with the trays 7 and 33 in the respective positions of Fig. 3 and the pneumatic jacks 44 and 46 are in the inoperative position of Fig. 7, (meanwhile the fixed bars 40, the movable bars 41 and the pusher 45 make up a rectangular closed hopper 58 accessible from top only, as shown in Fig 7), the conveyor for input 2, feeds one at a time the several articles to be stacked.Every time that an article 3 runs above the photoelectric cell 4, the latter delivers an electric pulse which, in addition to being counted by the counter 53, controls with an appropriate time delay, by timed actuation of the electromagnetic clutch 20, one revolution of the arbor 1 5 and thus a momentary shift of the upper trays 7 to the clearing position of Fig. 4 with an immediate subsequent snap back to the position of Fig. 3. The article meanwhile abuts the stop tray 5 and consequently falls into the underlying collection and stacking site 58; it is retained therein, against any possible undesirable undoing of the package, by the movable bars 41 which are in their closure position.

This sequence of steps is repeated at the arrival of every individual article 3 until the figure counted by the counter 53 attains the preselected value as set by the presetting and controlling unit 54. At this stage, the counter 53 controls the actuation of the pneumatic jacks 44 and 46: these in their turn, control, respectively, the shift of the movable bars 41 to the opening position of the collecting and stacking site 58 and the forward stroke of the ejector member 45 to eject the package of articles 50 thus formed out of the site 58, in cooperation with the conveyor 37 (Fig. 8), the motor of which, 38, is energized for a preselected time.Concurrently, the counter 53 also controls, by a timed actuation of the electromagnetic clutch 25, half-revolution of the arbor 26 and thus the shift of the lower trays 33 to the position of collection as shown in solid lines in Figs. 5 and 6. By so doing, the next article fed by the conveyor 2 and dropped by and from the upper trays 7 is collected and retained provisionally by the lower trays 33 without falling into the underlying collecting site 58.

Once the as-stacked package is dumped on the conveyor 47, the collection and stacking site 58 is restored to the starting position (Fig. 7) by the back stroke of the jacks 44 and 46, and the lower trays 33 are subsequently restored to their at rest position (Fig. 3) by a fresh energization of the electromagnetic clutch 25 for an additional halfrevolution of the shaft 26. The counter 53 is meanwhile resent.

The stacker can thus restart a stacking operation anew and this will have as a result another package of articles with the same, or a different, number of articles in it.

Claims

1. A stacker for articles of flattened outline, such as newspapers and magazines, the stacker comprising an input feeder adapted to feed one article at a time, an end-of-stroke stopping abutment for the article, upper trays which are displaced for each fed-in article from a position wherein the article is supported by them to a position of clearance adapted to permit the free fall of the article into an underlying collection site for stacking the articles to form a package of stacked articles, ejector means controllable to effect the ejection of the package of articles from - the site when the number of stacked articles attains a preselected value, and lower trays located between the upper trays and -the said site and controllable to be temporarily shifted from a rest position to a position of collection and momentary support of an article allowed to fall by the upper trays concurrently with each ejection action of the ejector means.

2. A stacker as claimed in claim 1, including means sensitive to the feed of each individual article by the input feeder and electronic delay means functionally inserted between the sensitive means and means for controlling the upper trays to control the shift of the upper trays from the said position of support to the said position of clearance with preselected time delay relative to the detection of the article by the said sensitive means.

3. A stacker as claimed in claim 1 or 2, in which the collecting and stacking site is provided with a supporting conveyor and means for frontally retaining the stacked articles, the said retaining means being controllably displaceable to a clearance position as the number of articles attains the preselected value.

4. A stacker as claimed in claim 3, in which the ejector means comprises a plate which can be transferred in the direction of feed of the said supporting conveyor from the rear of the said site.

5. A stacker substantially as described with reference to, and as shown in, the accompanying drawings.