Apparatus for handling and accumulating articles in a buffer area

Apparatus (1) for handling articles (2), including an endless infeed drive member (3) moving in an infeed direction (ID); an endless outfeed drive member (4) moving in a second, outfeed direction (OD); and an endless carrier conveyor (33) having. The carrier conveyor includes an infeed section (34) overlying the infeed drive member (3), whereby the infeed drive member (3) drives the infeed section (34) in the infeed direction (ID); an outfeed section (35) overlying the outfeed drive member (4), whereby the outfeed drive member (4) drives the outfeed section (35) in the outfeed direction (OD); and an arcuate intermediate section (36) bridging the infeed section (34) and the outfeed section (35) along a transfer path (37) between a diverting point (DIV) where the carrier conveyor (33) disconnects from the infeed drive member (3), and an inverting point (INV) where the carrier conveyor (33) connects the outfeed drive member (4).

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a National Stage of International Application No. PCT/JP2009/006836 filed Jul. 6, 2009, the contents of all of which are incorporated herein by reference in their entirety.

FIELD OF THE INVENTION

The invention relates to the field of article handling. More precisely, it relates to an apparatus for conveying and transferring articles from an infeed section to an outfeed section in a first in first out (FIFO) sequence.

BACKGROUND OF THE INVENTION

Apparatuses which permit the control of a flow of articles are useful wherever there is a need for accumulating articles in a buffer area between an upstream delivery station (e.g. a container filling and capping unit) and a downstream receiving station (e.g. a container labeling and/or wrap around station) in the event of a speed rate differential between the stations, e.g. when the downstream station is either shut down or running at an insufficient speed, whereby the articles fed from the upstream delivery station can not be properly handled.

Such apparatuses, which provide the ability to set the amount of articles temporarily stored in the buffer area, are commonly referred to as “accumulators”. Depending upon the room available and the configuration of the manufacturing plant, the accumulator may be of planar/straight or spiral/helical form.

U.S. Pat. No. 6,591,963 to Wipf discloses a straight storage apparatus comprising a carriage which can be displaced along a conveying plane. A pair of deflecting rollers is arranged on the carriage to guide an endless conveying means. One of the deflecting rollers subdivides a storage strand of the apparatus in an entry-side storage strand and an exit-side storage strand. The length of the storage strand can be changed, as does the capacity of the storage apparatus.

In theory, such a solution seems satisfactory because its construction appears quite simple. In practise however, drawbacks come to light when the setting of the apparatus must be achieved and in particular when the conveyor has to be tensioned. As disclosed in U.S. Pat. No. 6,591,963, tensioning means are provided on the carriage, the deflecting rollers being mounted in a mutually resilient manner. Although the tensioning process is not specifically disclosed in the Wipf patent, the skilled person can understand that the tensioning is achieved by moving the rollers towards each other, thereby exerting a traction effort on the circular portions of the conveying means wrapped around the deflecting rollers. The reaction effort exerted on the deflecting rollers by the conveying means generate undesired though inevitable bending and shear stresses on the axis of rotation of the rollers, thereby increasing the risk of axis wear, fatigue and, possibly, rupture.

U.S. Pat. No. 6,152,291 to Steeber et al, assigned to Hartness, discloses a spiral accumulator having an infeed conveyor driven in a first direction, and an outfeed conveyor spaced apart from the infeed conveyor and driven in an opposite direction. A transport member carrying a rotatable wheel is provided between the infeed and outfeed conveyors. The rotatable wheel is engaged on both sides by the infeed and outfeed conveyors so that the wheel is caused to rotate and the transport member may be caused to move along a path parallel to the infeed and outfeed conveyors depending upon the relative speed thereof. An article transfer member is also carried by the transport member for deflecting articles from the infeed conveyor to the outfeed conveyor. Articles deflected from the infeed conveyor temporarily run on a dead plate provided around the wheel over the space between the conveyors.

The Hartness accumulator does not have the hereabove mentioned drawback of Wifp's apparatus, since the stresses resulting from the tensioning of the infeed and outfeed conveyors are not transmitted to the rotatable wheel.

However, operating the Hartness accumulator has revealed uncontrolled movements of the articles in the turnaround area above the wheel, and more specifically at the junction of the (moving) infeed conveyor and the (still) dead plate, where the conveyor tends to move the articles ahead, whereas the dead plate is forcing them to loose headway. In addition, tacky articles may stick to the (still) surface of the transfer member. Subsequent uncontrolled movements of the articles may result in article jam and failure of the whole accumulating process, thereby causing the accumulator to be stopped, along with the entire upstream part of the manufacturing plant.

In order to improve article transfer, it was later on proposed to equip the article transfer member with an endless drive belt that is disposed along the transfer path so as to contact and move articles therealong, see U.S. Pat. No. 6,698,581 to Steeber et al, assigned to Hartness.

This solution seems satisfactory prima facie, but movement of the endless drive belt has to be synchronized with the infeed and outfeed conveyors. In order to achieve such synchronization, there is provided a complex and heavy transmission mechanism including a toothed wheel engaging the infeed and outfeed conveyors.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a solution to the hereabove mentioned drawbacks.

More specifically, it is an object of the invention to improve reliability of article transfer between an upstream delivery station and a downstream receiving station, e.g. in an article accumulator located in a buffer area.

Yet it is another object of the invention to facilitate movement of articles in a turnaround area between an infeed section and an outfeed section moving in opposite directions, in order to reduce the risks of article jam and increase machine speed rate and overall performance.

In accordance with the objects and purposes of the invention, there is provided an apparatus for handling articles, including:An endless infeed drive member moving in an infeed direction;An endless outfeed drive member spaced apart from the infeed drive member and moving in a second, outfeed direction opposite to the infeed direction;An endless carrier conveyor having:An infeed section overlying the infeed drive member and removably attached thereto, whereby said infeed drive member drives said infeed section in the infeed direction;An outfeed section overlying the outfeed drive member and removably attached thereto, whereby said outfeed drive member drives said outfeed section in the outfeed direction;An arcuate intermediate section bridging the infeed section and the outfeed section along a transfer path between a diverting point where the carrier conveyor disconnects from the infeed drive member, and an inverting point where the carrier conveyor connects the outfeed drive member.

In such an apparatus, the drive function and the support and conveying function are separated. The drive function is achieved through the underlying drive members, whereas the article support and conveying function is achieved through the carrier conveyor. Accordingly, there is no need for applying a great tension on the carrier conveyor, which remains passive. As a result, in normal operation no damaging stress is exerted by the carrier conveyor on the parts of the apparatus with which it is in contact.

The endless infeed drive member, the endless outfeed drive member and the endless carrier conveyor are e.g. endless chain belts, each including a plurality of connecting links.

In a preferred embodiment, the endless carrier conveyor is magnetically attached to the infeed drive member and to the outfeed drive member.

For example, each connecting link of the infeed and outfeed drive members comprises a supporting plate made of a ferromagnetic metal, whereas each connecting link of the endless carrier conveyor comprises a permanent magnet which, in the infeed section, is magnetically attached to the supporting plate of a connecting link of the infeed drive member and which, in the outfeed section, is magnetically attached to the supporting plate of a connecting link of the outfeed drive member.

In a preferred embodiment, the apparatus further comprises a carriage comprising a transfer wheel pivotally mounted between the infeed and outfeed drive members and drivingly engaged on its circumference by the endless carrier conveyor which causes the transfer wheel to rotate around a central axis, whereby said carriage remains still as long as there is no speed difference between the drive members moving in opposite directions, whereas as soon as there exists a speed difference the carriage travels in the direction of the faster drive member. The arcuate intermediate section of the endless carrier conveyor is tangent to and frictionally engages the transfer wheel.

The carriage may further comprise a dead plate mounted adjacent to the transfer wheel and extending between the infeed and outfeed drive members, whereby the endless carrier conveyor rides on the dead plate in the intermediate section.

In a preferred embodiment, the carriage further includes an arcuate guide member extending outwardly along and adjacent the intermediate section of the endless carrier conveyor.

In addition, the apparatus may also comprise:an infeed drive mechanism for displacing each drive member, said infeed drive mechanism comprising a drive sprocket engaging the drive member and a variable speed drive motor pivotally coupled to the drive sprocket, anda driven pulley engaged by the endless carrier conveyor, mounted parallel and adjacent to the drive sprocket.

The above and other objects and advantages of the invention will become apparent from the detailed description of preferred embodiments, considered in conjunction with the accompanying drawings.

DESCRIPTION OF PREFERRED EMBODIMENTS

Turning now to the drawings, and more specifically toFIG. 1, there is shown an embodiment of an apparatus1for handling and accumulating articles2(e.g. containers) in a buffer area between an upstream delivery station and a downstream receiving station.

The apparatus1comprises an endless infeed drive member3and an endless outfeed drive member4parallel to and spaced apart from the infeed drive member3. The endless infeed drive member3moves in an infeed direction ID, whereas the endless outfeed drive member4moves in an outfeed direction OD opposite to the infeed direction ID.

InFIG. 1only part of the apparatus1is represented. It can be seen on the right of the drawing that the drive members3,4are cut, but the skilled person may easily imagine that in practise they may run much longer, depending upon the size of the buffer area needed. In addition, although the section of the apparatus1illustrated inFIG. 1is straight, it shall be understood that any shape (arcuate, looped, helical, etc.) may be suitable as well, depending upon the configuration of the available space surrounding the apparatus1.

Each drive member3,4rests on and runs along a respective support frame5comprising a pair of spaced apart and parallel walls6each including a vertical section7and a horizontal support section8. The support sections8are spaced apart and together define a longitudinal groove9forming a guiding track for the respective drive member3,4. In a preferred embodiment illustrated onFIG. 4, a pair of guiding pads10is mounted on the support sections8. Each guiding pad10is made of a low-friction material, such as nylon or PTFE.

In the illustrated preferred embodiment, each drive member3,4is an endless chain belt including a plurality of connecting links11. Each connecting link11is made of a ferromagnetic metal such as a ferritic stainless steel and comprises a planar supporting plate12and, integrally formed therewith, a male connecting part13and an opposite female connecting part14receiving a male connecting part13of an adjacent link11. Attachment of two links11is achieved by means of a connecting pin15inserted both in the male and female connecting parts13,14, whereby the links11are hingedly attached to one another around the connecting pin15.

Each link11also comprises a pair of guiding tabs16integrally formed with the supporting plate12and downwardly protruding therefrom. As depicted onFIG. 4, each link11rests on the horizontal support section8, whereby the supporting plate12lays on the guiding pads10with the guiding tabs16received therebetween. At a lower end, each tab16is hooked and comprises a lateral protrusion17to prevent vertical tear-out of the link11from the guiding track9.

Arranged between the support frames5is a movable carriage18including a pair of spaced apart wheels19,20each pivotally mounted between the infeed and outfeed drive members3,4around a central axis21. The wheels19,20rest on a pair of rails22longitudinally fixed to inner walls6of the support frames5.

The wheels19,20are connected to each other by means of a connecting rod23hingedly mounted between both axis21, so that the movable carriage18is able to follow the shape of the support frames5, as will be disclosed in further details hereinafter.

The carriage18subdivides the apparatus1into a storage part24and an idle part25.

The storage part24of the apparatus1extends between a fixed proximal end26, located on the side of the delivery and receiving stations, and a movable end formed by a first wheel19of the carriage18, hereinafter referred to as a transfer wheel.

The idle part25of the apparatus1symmetrically extends between a fixed distal end27, opposite to the proximal end26, and a movable end formed by the other wheel20of the carriage18, hereinafter referred to as an idle wheel.

The drive members3,4are motor-driven separately, so that the infeed drive member3is driven independently from the outfeed drive member4. In the depicted embodiment, the apparatus1is substantially symmetrical with respect of a vertical axis located in the center of the carriage18between the wheels19,20.

The infeed drive member3is displaced in the infeed direction ID by an infeed drive mechanism28located in the storage part24, at the proximal end26. The infeed drive mechanism28comprises a drive sprocket29pivotally mounted on the support frame5and engaging the infeed drive member3, and a variable speed drive motor (not shown) pivotally coupled to the drive sprocket29through a drive shaft30. At the distal end27, the infeed drive member3runs in loop on a driven reversing pulley pivotally mounted on the support frame5. The infeed drive member3may be tensioned by adjusting the position of this driven pulley.

As depicted onFIG. 2, the drive sprocket29comprises a peripheral series of teeth31which mesh with the connecting parts13,14of the links11, whereas the links11simply frictionally engage the driven reversing pulley.

Symmetrically, the outfeed drive member4is displaced in the outfeed direction OD by an outfeed drive mechanism similar to the infeed drive mechanism28but located in the idle part25of the apparatus1at the distal end27, whereas, at the proximal end26, the outfeed drive member4runs in loop on a driven reversing pulley32.

Rotational speed of the motors is controlled e.g. by a computer control unit which allows adjustment of the linear speed of the infeed and outfeed drive members3,4. In normal operation the drive members3,4move at the same speed in opposite directions, so that there is no speed differential therebetween.

The apparatus1further comprises an endless carrier conveyor33on which the articles2are supported and transported from an article entry point IN, located at the proximal end26on the side of the upstream delivery station, where the articles2enter the apparatus1, and an article exit point OUT, also located at the proximal end26but on the side of the downstream delivery station, where the articles2leave the apparatus1.

The endless carrier conveyor33overlies the drive members3,4and is removably attached thereto.

More precisely, on the one hand, the endless carrier conveyor33comprises an infeed section34overlying the infeed drive member3and removably attached thereto, running from the article entry point IN to a diverting point DIV, adjacent the periphery of the transfer wheel19, where the carrier conveyor33laterally disconnects from the infeed drive member3.

On the other hand, the endless carrier conveyor33comprises an outfeed section35overlying the outfeed drive member4and removably attached thereto, running from an inverting point INV, adjacent the transfer wheel19and diametrically opposite to the diverting point DIV, where the carrier conveyor33laterally connects the outfeed drive member4, to the article exit point OUT.

The carrier conveyor33is not directly motor-driven. The infeed section34of the endless carrier conveyor33is driven in the infeed direction ID by the infeed drive member3, whereas the outfeed section35is driven in the outfeed direction OD by the outfeed drive member4.

As depicted onFIG. 1andFIG. 3, the endless carrier conveyor33comprises an arcuate intermediate section36bridging the infeed section34and the outfeed section35. The intermediate arcuate section36forms a loop along a semi-circular transfer path37around the periphery of the transfer wheel19, between the diverting point DIV and the inverting point INV.

The transfer wheel19is frictionally drivingly engaged on its circumference by the intermediate section36of the endless carrier conveyor33which is tangent to the transfer wheel19and causes the latter to rotate around its central axis21. In other words, the transfer wheel19acts as a driven reversing pulley deflecting the carrier conveyor33from the infeed drive member3to the outfeed drive member4.

Symmetrically, the idle wheel20is frictionally engaged on its circumference by an intermediate section36′ of the portion of the carrier conveyor33located in the idle part25of the apparatus1, in a direction opposite to the transfer wheel19.

The carrier conveyor33is and endless chain belt comprising a plurality of hinged connecting links38. Each link38comprises a body39and a head40pivotally mounted on the body39around a vertical axis. More specifically, the body39comprises a hollow male section41having a cylindrical bore42in which is received a cylindrical shaft43integrally formed on the head40, whereby the head40is capable of rotating around the shaft43with respect of the body39. As depicted onFIG. 7, the male section41is also provided with a pair of lateral elongated windows44.

The body39further comprises a female section45having a pair of longitudinally protruding flanges46receiving a male section41of an adjacent link38. Each flange46is provided with a through hole47. Attachment of two adjacent links38is achieved by means of a connecting pin48inserted both in the through holes47and the lateral windows44across the shaft43of the head40, whereby the links38are hingedly attached to one another around the connecting pin48, which also serves to fix the head40to the body39with angular displacement around the shaft43.

As depicted onFIG. 2, the endless carrier conveyor33runs on a plurality of driven reversing pulleys49,50. More precisely, the infeed section34frictionally engages an infeed driven reversing pulley49mounted to the support frame5at the proximal end26on the side of the upstream delivery station, parallel and adjacent to the drive sprocket29of the infeed drive mechanism28. Symmetrically, the outfeed section35frictionally engages an outfeed driven reversing pulley50mounted to the support frame5at the proximal end26on the side of the downstream receiving station, parallel and adjacent to the driven reversing pulley32of the outfeed drive member4.

InFIG. 2only some of the links11,38of the drive members3,4and carrier conveyor33are represented, in order to allow visual access to the drive sprocket29and to the reversing pulleys49,50.

In a preferred embodiment, the carrier conveyor33is magnetically attached to the infeed and outfeed drive members3,4.

More specifically, as depicted onFIG. 8, each link38of the endless carrier conveyor33comprises a cylindrical permanent magnet51mounted in a corresponding bore52formed in the shaft43of the head40, whereby a lower planar surface53of the magnet51slightly protrudes downwardly from the link38.

As a result, each link38of the infeed section34is magnetically attached to an underlying ferromagnetic supporting plate12of a link11of the infeed drive member3. Symmetrically, each link38of the outfeed section35is magnetically attached to an underlying ferromagnetic supporting plate12of a link38of the outfeed drive member4.

In the linear infeed and outfeed sections34,35, the overall attachment force of the carrier conveyor33to the underlying infeed and outfeed drive members3,4is equal to the sum of the individual magnetic attachment forces of each magnet51to the underlying supporting plate12. Therefore, vertical or horizontal manual tear-off of the carrier conveyor33as a whole, from the underlying drive members3,4, is quite difficult. The longer the infeed and outfeed sections34,35, the stronger the attachment of the carrier conveyor33to the drive members3,4. Dimensional and material provisions may vary according to the use of the apparatus1. Ordinary magnets51can provide an individual attachment force to a stainless ferritic surface of more than 0.3 N/cm2, so that a magnet having a diameter of 2 cm is able to provide a magnetic attachment force of about 10 N.

However, one advantage of such a magnetic attachment is that is permits an easy progressive disconnection of the carrier conveyor33from the underlying drive member3,4, either vertically or horizontally.

At the level of the infeed drive mechanism28, the drive sprocket29meshes with the links11of the infeed drive member3which is thereby forced vertically down. As the carrier conveyor33remains horizontal under the longitudinal tension exerted by the driven reversing pulley49, the infeed drive member3is disconnected link by link from the overlying infeed section34of the carrier conveyor33. Similarly, the driven reversing pulley32, around which the outfeed drive member4is winded, forces the outfeed drive member4to disconnect link by link from the underlying outfeed section34of the carrier conveyor33, which remains horizontal under the longitudinal tension exerted by its own driven reversing pulley50.

At the diverting point DIV, where the carrier conveyor33winds around the transfer wheel19, the conveyor33is laterally forced out of the underlying infeed drive member3, whereby the links38of the carrier conveyor33progressively slide out laterally from the underlying links11until they separate therefrom when the permanent magnet51leaves the supporting plate12.

As long as there is no speed difference between the drive members3,4moving in opposite directions, the carrier conveyor33only exerts a peripheral frictional effort on the transfer and idle wheels19,20, whereby the carriage18remains still with respect of the support frames5.

On the contrary, as soon as there exists a speed difference between the infeed and outfeed drive members3,4, the carriage18slidingly travels on the rails22in the direction of the faster drive member3or4.

Such a situation occurs when the buffer area capacity has to be set according to a difference of speed rate between the upstream delivery station and the downstream receiving station.

Whenever the speed rate of the upstream delivery station is greater than the speed rate of the downstream receiving station, more articles2need to be accumulated in the buffer area, which therefore has to be enlarged. In order to do so, the linear speed of the outfeed drive member4is lowered with respect of the linear speed of the infeed drive member3, whereby there appears a negative speed differential between the outfeed section35of the carrier conveyor33, which runs at the same speed as the underlying outfeed drive member4, and the infeed section34of the carrier conveyor33, which runs at the same speed as the underlying infeed drive member3. As a result, the carrier conveyor33exerts on the idle wheel20, through its corresponding intermediate section36′, a tension directed longitudinally towards the distal end27of the apparatus1, whereby the carriage18is slidingly displaced between the support frames5towards the distal end27.

On the contrary, whenever the speed rate of the upstream delivery station is lower than the speed rate of the downstream receiving station, less articles2need to be accumulated in the buffer area, which therefore has to be reduced. In order to do so, the linear speed of the infeed drive member3is increased with respect of the linear speed of the outfeed drive member4, whereby there appears a positive speed differential between the outfeed section35and the infeed section34of the carrier conveyor33. As a result, the carrier conveyor33exerts on the transfer wheel19, through its intermediate section36, a tension directed longitudinally towards the proximal end26of the apparatus1, whereby the carriage18is slidingly displaced between the support frames5towards the proximal end26.

In order to support the intermediate section36of the carrier conveyor33along the transfer path37, the carriage18is provided with a dead plate54mounted on the connecting rod23adjacent to the transfer wheel19and extending between the infeed and outfeed drive members3,4, whereby the endless carrier conveyor33rides on the dead plate54in the intermediate section36and is prevented from slipping downwards out of the periphery of the transfer wheel19under the weight of the articles2.

In addition, in order to prevent the articles2from slipping radially or even falling out of the intermediate section36under inertial forces, the carriage18comprises an arcuate guide member55extending outwardly along and adjacent the intermediate section36. In the illustrated embodiment, the guide member55is formed of a semi-circular metallic plate fixed to the dead plate54and extending above the infeed and outfeed drive members3,4up to an outer edge thereof, in order to accompany the articles all along the transfer path37.