Description

Conveyor and control unit for box containers

Technical Field

This invention relates to a conveyor and control unit for products, in particular for box containers.

In particular, the invention can be advantageously applied to the packaging machinery industry to provide means of conveying box-shaped containers such as, preferably, paperboard cartons and the like containing one or more packs (blister packs or other types of pack) for pharmaceuticals (e.g. tablets, capsules, pills, vials, etc.), which this description expressly refers to without thereby limiting the scope of the inventive concept, along a feed line extending through at least one control station.

Background Art

At present, in prior art packaging lines, cartons of the above mentioned type are handled and conveyed by one or more endless conveyors trained around power-driven pulleys and usually installed one after the other Ln order to feed the cartons in succession along a flat (substantially horizontal) path through different operating stations.

One or more of these stations is used to check and control certain qualitative and physical properties of the cartons in transit such as, for example: quality, correct closure of side flaps, etc.

One important physical property to be checked at one of these stations is the weight of each carton: this property must be measured very accurately because it indicates whether the carton has been correctly filled with the predetermined number of products. The weight must therefore be checked individually on each single carton.

In some packaging lines, this type of check is performed by physically moving each carton from the feed line onto the weighing device (checkweigher) and then back onto the feed line.

This is, however, a considerably complex solution incompatible with the high production speeds and continuous feed motion of state-of-the-art packaging

TRANSLATION (RULE 12.3) 17 APRIL 2009

machines.

In an attempt to overcome this problem, efforts have been made to place the weighing station directly on the continuous feed line: unfortunately, the accuracy of weight measurements is frequently altered by the conveying means in that the conveyor belts and the accessories connected with them and used to feed the cartons through the weighing station constitute an obstacle and hence a limit to the operating efficiency of the weighing means (checkweigher) of the weighing station itself.

In another alternative solution, described in United States patent document 7,408,124, use is made of two conveyors with vertical axes, that is to say, having vertical surfaces facing each other for bilaterally holding each box-shaped object, and a weighing device mounted inside the channel formed by the two conveyor belts.

This weighing device has a horizontal surface formed by several power- driven belts, the middle one of which is the one that actually weighs the box- shaped object.

In brief, the box-shaped object is moved by the conveyor belts towards a horizontal, power-driven infeed belt where the conveyor belts are diverted and move clear of the box-shaped object. The box-shaped object is then transferred to the power-driven weighing belt which checks its weight and transfers it to a power-driven outfeed belt where the box-shaped object is once again gripped by the conveyor belts. The power-driven infeed, weighing and outfeed belts advance the box-shaped objects at the same speed.

This weighing unit, which is undoubtedly an improvement on the solutions that preceded it, is not, however, free of disadvantages due to:

- limited conveying stability since the objects are suspended, without flat horizontal support, which means that this solution is limited to relatively light products;

- limited guarantees of the box-shaped object remaining correctly spaced before and after being weighed;

- constructional and positioning complexity of the weighing means, which must always be adjusted in height according to both the size of the box-shaped objects and their position, which is not always centred on the conveyor belts themselves. As a result, this solution is still not entirely satisfactory for the high speeds

of current packaging machines.

Aim of the Invention

This invention has for an aim to overcome the above mentioned problems. It is in particular an aim of this invention to provide a conveyor and control unit for box containers capable of advancing the containers through a weighing station while effectively and accurately facilitating the step of dynamically weighing them, and at the same time optimizing container feed flow control and maintaining the position and, hence, the spacing of the containers along the conveyor line.

Brief Description of the Drawings

The technical characteristics and advantages of the invention, with reference to the above aims, may be clearly inferred from the description which follows, with reference to the accompanying drawings which illustrate a preferred non- limiting embodiment of the conveyor and control unit and in which:

- Figure 1 is a schematic side view, with some parts cut away in order to better illustrate others, of a conveying and control unit according to the invention;

- Figure 2 is a top plan view, with some parts cut away in order to better illustrate others, of the conveying and control unit of Figure 1.

Detailed Description of the Preferred Embodiments of the Invention

With reference to Figures 1 and 2, the conveyor and control unit for products, in particular for box containers, is used preferably, but without limiting the scope of the invention, for paperboard cartons 1 and the like containing one or more blister packs for pharmaceuticals (e.g. tablets, capsules, pills, vials, etc.).

The unit, labelled 100 as a whole, may form part of a prior art packaging line (not illustrated) and, as will become clearer as this description continues, is designed to feed the cartons 1 in a substantially horizontal feed direction A and to check the weight of each carton 1 using a weighing unit 3.

The conveyor and control unit 100 essentially comprises: first belt means comprising a first belt 2 for feeding the cartons 1 and the above mentioned weighing unit 3 comprising means 5 for weighing the cartons 1.

More specifically, on the first belt 2 the cartons 1 rest at least partly on an active section 2a of the first belt 2 itself in such a way as to advance in the feed

direction indicated by the arrow A and at a first speed V 1.

As shown in Figure 2, each carton 1 rests substantially with a central part of its underside Ib on the active section 2a of the first belt 2.

The first belt 2 moves continuously and is trained in a closed loop around a pair of horizontal pulleys 8 (of which only one is visible in Figure 1) and at least one of which is power driven by a motor M8 illustrated as a block in Figure 1.

In addition to the above, the first belt 2 is equipped with a plurality of pushing elements 9 protruding from the first belt 2 itself, equispaced along the first belt 2 and designed to abut a vertical wall Ia of a respective carton 1, in such a way that the cartons 1 advance at a predetermined distance or spacing P from each other.

The conveyor and control unit 100 also comprises:

- a first conveying member 30 positioned on both sides of the first belt 2 comprising second supporting and transporting belt means 4a positioned on opposite sides of the first belt 2; and

- a second conveying member 31 positioned on both sides of the first belt 2 comprising third supporting and transporting belt means 4b positioned on opposite sides of the first belt 2.

The means 5 for weighing the cartons 1 in transit on the conveying members 30, 31 are advantageously connected to the second conveying member 31.

The conveying members 30, 31 are designed to intercept the cartons 1 at least for a predetermined stretch parallel to the active section 2a of the first belt 2 and at a second speed V2 different from the first speed Vl of the first belt 2.

Further, the numerals 6 and 7 denote means positioned and operative between the first belt 2 and the conveying members 30, 31 and designed to move the cartons away from/towards the first belt.

Looking more closely at the technical details, the conveying members 30, 31 are mounted one after the other and the second belt means 4a and third belt means 4b forming part of them are trained in a closed loop around respective sets 10 and 1 1 of three horizontal pulleys, one of which 10m, 11m in each set is power-driven: the second and third belt means 4a and 4b move preferably continuously at the same second speed V2.

In practice, the second belt means 4a and the third belt means 4b each comprise a pair of second belts 32 and third belts 33, respectively, parallel to and positioned on opposite sides of the first belt 2.

In particular, for both the second belt means 4a and the third belt means 4b, the second speed V2 is higher than the first speed Vl of the first belt 2.

The power-driven pulleys 10m and 1 Im are connected to a single motor M4 illustrated as a block in Figure 1. Operating stretches Tl and T2 of the second and third belt means 4a and 4b, respectively, are designed to laterally support the underside 1 b of each carton 1 and are parallel to the active section 2a of the first belt 2.

The stretches Tl and T2 extend at a height H4 greater than the height H2 of the active section 2a of the first belt 2, these heights being referenced to an axis of rotation X8 of the power-driven pulley 8 of the first belt 2: thus, in this embodiment, the stretches Tl and T2 move along the same path as the belt section

2a for a certain length but at a greater height.

Further, the difference between the heights H4 and H2 is in any case less than the height H9 of the pushing element 9 so that, after being weighed, the carton 1 can be re-taken by the relative pushing element (9) along the feed path.

To enable the conveying members 30, 31 to intercept the cartons 1 and temporarily carry them so that each carton 1 can be weighed, there is an element 6 acting on the belt means 4a in such a way as to move the cartons away from the first belt and forming part of the above mentioned means for moving the cartons away from and towards the first belt.

More specifically, in this particular case, the element 6 is embodied by two idler pulleys 6 (only one of which is shown in Figure 1) that turns about a horizontal axis and is positioned along the operating stretch Tl of the second belt means 4a in such a way as to incline an initial part TIa of the operating stretch Tl upwardly relative to the first belt 2: thus, the carton 1 is directed upwards as it moves from the first belt 2 onto the second belt means 4a.

The rest of the stretch Tl of the second belt means 4a and the stretch T2 of the third belt means 4b extend in the same plane and the third belt means 4b, downstream of the second belt means 4a, are connected directly to the weighing means 5.

The means for moving the cartons away from/towards the first belt also comprise an element or block 7, located downstream of the third belt means 4b relative to the feed direction A, and having a downwardly inclined fixed surface designed to enable the belt 2 to intercept the carton 1, in step, after it has been weighed and is positioned statically on the block 7 itself: interception is effected

by one of the pushing elements 9 and, more specifically, by the same pushing element 9 which had previously caused the carton 1 to advance towards the first conveying member 30.

The block 7 is comprised of two half-parts located on each side of the first belt 2.

As may be inferred from Figure 1 , the cartons 1 are stabilized at the top by a fixed contact surface 20 at least in the region where they are engaged by the first belt 2, while in the region where they advance on the second and third belt means 4a and 4b there is a recessed zone 21 designed to allow the carton 1 to be raised and to travel at a higher level while it is weighed without interference from external structures.

Although the embodiment described up to now substantially involves raising and lowering the cartons 1 to move them momentarily away from the first belt 2 by means of the inclined stretch TIa and the block 7, in an alternative embodiment, it is the first belt 2 that might be moved away, for example downwardly, by means of suitable idler pulleys, in such a way as to release the cartons 1 on the conveying members 30, 31 which, in this case, would have completely horizontal operating stretches for advancing the cartons 1 : this alternative embodiment thus remains within the scope of protection of this invention.

During the normal operation of the unit 100 described with reference to Figures 1 and 2, the carton 1 is delivered to the first belt 2 by customary conveyors and handling units, not illustrated, located upstream of the first belt 2.

A respective pushing element 9 advances the carton 1 in the feed direction A until the carton 1 comes into contact with the stretch TIa of the second belt means 4a.

At this point, the carton 1 is picked up by the second belts 4a. Thanks to the upwardly inclined path of the stretch TIa, the carton 1 moves away from the first belt 2 and, thanks to the speed V2 of the second belt means 4a, faster than the speed Vl of the first belt 2, the carton 1 is accelerated and moves away from the respective pushing element 9.

Next, on the rest of the stretch Tl of the second belt means 4a, the carton 1 travels horizontally at a higher level than the first belt 2 and still at the speed V2 so that it moves still further away from the pushing element 9 to reach the stretch T2 of the third belt means 4b on which it is weighed as it moves on the third belt

means 4b themselves. It should be noticed that while the carton 1 is being weighed, the carton 1 is in contact only with the third belt means 4b and, more specifically, with the third belts 33.

After being weighed, the carton 1 , which has in the meantime continued to travel at a faster speed V2 than the speed V 1 of the first belt 2, is released onto the block 7 and stops in a stand-by position.

The pushing element 9 related to the carton 1 just weighed and standing by on the block 7, now catches up with the carton 1 , which has in the meantime been handled by the conveying members 30, 31, and strikes the back Ia of the carton 1, causing the latter to start moving again at the first speed Vl and in such a way that the carton 1 moves onto the first belt 2 again, with the required spacing P between it and the cartons 1 before and after it.

A unit structured in this way offers the following advantages:

- optimum and effective container feed along a packaging line even at high production speeds;

- container feed is such that each container is weighed precisely and dynamically as it crosses the weighing station, without upsetting feed flow, which remains under optimum control at all times;

- container spacing after weighing is precisely maintained so that subsequent packaging operations that require the containers to be spaced exactly on the conveyor belt can be performed in optimum manner;

- the containers are picked up and released with a quick and sure movement thanks to parallel belts on opposite sides of the first feed belt and to the downwardly inclined block.