DEVICE FOR STORING A SHEET PILE IN A CONVERTING MACHINE AND CONVERTING MACHINE

A device for storing a sheet pile in a converting machine (10) comprises a transfer mechanism (28) for delivering sheets (22) into a piling area (26) of the device (22), and a sampling plate (44) which is adjustable between a sampling position and an access position, wherein the top of the piling area (26) is covered by the sampling plate (44) when the sampling plate (44) is in the sampling position and the top of the piling area (26) is free when the sampling plate (44) is in the access position.

The invention relates to a device for storing a sheet pile in a converting machine and a converting machine.

Converting machines are used in the packaging industry for processing raw materials, e.g. cardboard, paper or foils, into intermediate or finished products, typically in the form of sheets. Converting operations can be printing, cutting, creasing, stamping and/or folding-gluing. Accordingly, the term converting machine here also generally means sheet processing machine. The sheets can be collected in vertical stacks after converting in a designated piling area of the converting machine.

In order to control the quality of the produced sheets, it is necessary to regularly collect sample sheets during operation of the converting machine. For this purpose, converting machines can have mechanisms for temporarily creating an access to the piling area such that an operator can manually pick sample sheets from the pile of produced sheets. However, to ensure a controlled and safe access for the operator, known mechanisms need redundant security systems which restrict the available space for the operator and/or necessitate the converting machine to stop the sheet production for extended periods of time.

The object of the invention is to provide a device which allows for an easier collection of sample sheets in a converting machine. Preferably, the device allows reducing the downtime of a converting machine.

The object of the invention is solved by a device for storing a sheet pile in a converting machine wherein the device comprises a transfer mechanism for delivering sheets into a piling area of the device, and a sampling plate which is adjustable between a sampling position and an access position, wherein the top of the piling area is covered by the sampling plate when the sampling plate is in the sampling position and the top of the piling area is free when the sampling plate is in the access position.

The expression “the piling area is covered” here has the meaning of the sampling plate being arranged above the piling area so that sheets delivered by the transfer mechanism cannot reach the piling area anymore but are rather collected by the sampling plate.

The sampling plate especially completely covers the top of the piling area.

The sheets are subjected to one or more converting operations by the converting machine, e.g. printing, cutting, creasing, stamping and/or folding-gluing and are fed by the converting machine by means of the transfer mechanism to the piling area.

The transfer mechanism can be the same transfer mechanism used in the overall converting machine or be connected to an additional converting machine transfer mechanism.

During operation of the converting machine, the sheets are stacked in a vertical pile in the piling area of the device as long as the sampling plate is in the access position. If the sampling plate is in the sampling position, the sheets produced by the converting machine are collected on the sampling plate instead.

Preferably, in the sampling position, the sampling plate is parallel to the sheets in the sheet pile so that further sheets produced by the converting machine can be placed on the sampling plate in the same manner as they would be stacked on the sheet pile.

The sheets can be made out of cardboard, paper, foil or a composite material.

The device according to the invention allows for collecting sample sheets in an easy manner by adjusting the position of the sampling plate. The at least one sample sheet on the sampling plate can afterwards be collected and checked for its quality.

Preferably, an operator can reach the sampling plate for collecting the sheets when the sampling plate is in the access position while the converting machine is in operating mode, i.e. processes sheets. In this way, the downtime of the converting machine is reduced.

The sampling plate can be adjusted from the access position into the sampling position manually and/or by a drive.

In one variant, the sampling plate at least partially extends outside of a housing of the device when being in the access position.

The housing of the device can be the housing of the converting machine, too.

With other words, the sampling plate preferably at least partially extends out of the converting machine to allow the operator to easily pick up the sheets collected by the sampling plate without the need for an access to inner parts of the converting machine.

In another variant, the sampling plate is removably engagable with an opening of the housing. In this way, it is possible to insert the sampling plate into the device only when needed, i.e. when sheets need to be collected.

The sampling plate can have a folding edge to flip over the part of the sampling plate which extends from the housing. This allows for a more compact storage of the sampling plate when it is not needed to collect sheets.

In another variant, the sampling plate comprises several segments which can be at least partially folded against each other. This allows for non-linear movements of the sampling plate when being adjusted between the sampling position and the access position.

The device preferably comprises a guide rail extending at least partially along a side boundary of the piling area and along which the sampling plate moves when being adjusted between the access position and the sampling position.

At least the part of the guide rail which extends along the side boundary of the piling area can be parallel to the sheets of the sheet pile.

The guide rail ensures a controlled movement of the sampling plate when the sampling plate is adjusted to the sampling position.

Preferably, the device comprises two guide rails at opposite side boundaries of the piling area. In this way, the movement of the sampling plate is further secured and shifting and tilting of the sampling plate is prevented.

The one or more guide rails especially extend from the housing of the device over the full length of the respective side boundary of the piling area.

Preferably, the device comprises a jogger which is arranged between the sampling plate and a front boundary of the piling area when the sampling plate is in the access position.

The jogger is used to align the sheets in the sheet pile when and/or after they are and/or have been delivered by the transfer mechanism. For this purpose, the jogger can be tilted back and forth towards and away from the front boundary of the piling area so that the sheets in the piling area are aligned to each other.

The front boundary of the piling area especially is perpendicular to the side boundary of the piling area.

The jogger especially extends over the full length of the front boundary of the piling area.

Further, the device can comprise at least one lateral jogger arranged at the side boundary of the piling area.

The lateral jogger is also used to align the sheets in the sheet pile when and/or after they are and/or have been delivered by the transfer mechanism. For this purpose, the lateral jogger can be tilted back and forth towards and away from the side boundary of the piling area.

The device can comprise several lateral joggers, especially at least one lateral jogger at both side boundaries of the piling area.

The lateral jogger can extends over the full length of the side boundary of the piling area.

In one embodiment, the jogger and/or the at least one lateral jogger can be adjusted between a working position and a clearing position by a drive element, wherein the sampling plate can be adjusted into the sampling position only when the jogger and/or the at least one lateral jogger is/are in the clearing position.

In this embodiment, the jogger and/or the lateral jogger do not need to be mounted such that they are at all times below or above the level on which the sampling plate is moved over the piling area. This allows for reducing the necessary size of the device.

At the same time, the jogger and/or the lateral jogger prevents the sampling plate from accidentally blocking the piling area.

The drive element can comprise a piston which can be driven electrically, pneumatically and/or hydraulically.

The device can comprise a sensor adapted for monitoring the position of the sampling plate.

The sensor is especially located between the housing of the device and the piling area, preferably between the housing of the device and the jogger.

The sensor allows to determine if the sampling plate is moved out of the access position. In this case, the jogger and/or the one or more lateral joggers can be automatically adjusted into the clearing position.

The sensor can be a light barrier.

The object of the invention is further solved by a converting machine comprising a device as described before.

FIG.1shows a converting machine10according to the invention. The converting machine10is composed of several modules which are arranged one after another. In the shown embodiment, the converting machine10comprises a loading station12, a feeder14, a converting station16, a discharge station18, and a device20according to the invention.

The converting machine10has a running direction R which is defined by the direction in which sheets are being processed.

The loading station12is used for supplying the converting machine10with raw sheets to be processed. The raw sheets can be made out of cardbox, paper or plastic.

The individual raw sheets are taken out of the loading station12by the feeder14and fed into the converting station16.

The converting station16can be a cutting station, an embossing station or a stamping station. In the shown embodiment, the converting machine comprises a platen press24. In the converting station16, the raw sheets are converted to sheets22.

The discharge station18is used to transfer the sheets22from the converting station16to a piling area26of the device20. The discharge station18can also be used to ensure correct alignment of the sheets22.

The sheets22are moved along the running direction R by a transfer mechanism28. The transfer mechanism28is adapted to individually transfer each single sheet22from the feeder14to the device20.

The transfer mechanism28comprises several gripper bars30which take turns to grip a sheet22at its front edge and to pull the sheet22through the stations of the converting machine10.

The gripper bars30are connected to a chain32which is moving in a closed circle. The chain32moves in a step-wise manner, whereby with each step the sheet22is moved to the next station of the converting machine10.

In the device20, the sheets22are released from the transfer mechanism28to form a pile of sheets in the piling area26, e.g. on a pallet34.

Accordingly, in the shown embodiment, only a single transfer mechanism28is used for all modules of the converting machine10, including the device20. Generally, the device20could comprise its own transfer mechanism28which is connected to a further converting machine transfer mechanism.

At a front boundary36of the piling area26, a jogger38is arranged. The jogger38is used to align the processed sheets22along the running direction R in the piling area26. This is done by providing a flat surface by the jogger38against which the sheets22can be pushed when delivered into the piling area26by the transfer mechanism28.

Further, the device20comprises a back jogger39which is arranged at a back side of the piling area26opposite to the front side of the piling area26. Accordingly, the back jogger39is arranged opposite to the jogger38.

Further, the jogger38can tilt back and forth to align the sheets22in the piling area26.

The device20comprises a housing40which in the shown embodiment is also part of the housing of the converting machine10.

The housing40comprises a window42so that an operator of the converting machine10can look into the converting machine10, especially on the sheets22in the piling area26.

The housing40further has an opening43through which a sampling plate44partially extends outwards from the housing40. The sampling plate44further comprises handles45which can be used by the operator to adjust the position of the sampling plate44.

Additionally, the device20has a display unit46with a display48and control elements50. The display48can also be a touch-sensitive display. In this case, the control elements50can be incorporated into the display48. The display unit46can be used by an operator to control the device20, preferably to control all modules of the converting machine10.

FIG.2shows a perspective view of parts of the device20.

The jogger38and the back jogger39extend essentially over the full length of the front and back surface of the piling area26, respectively.

As can be seen fromFIG.2, additionally to the jogger38and the back jogger39, the device20further comprises two lateral joggers52. The lateral joggers52are arranged at side surfaces of the piling area26, wherein each of the two lateral joggers52are arranged opposing each other at opposite side surfaces of the piling area26.

The device20further comprises two guide rails54, each one extending along one of the side boundaries of the piling area26. The guide rails54further partially extend outwards of the housing40.

The sampling plate44is arranged on the guide rails54.

InFIGS.1and2, the sampling plate44is in an access position. In the access position, the top of the piling area26is free so that sheets22can be transferred by the transfer mechanism28to the piling area26to form a sheet pile.

Additionally, the jogger38is arranged at a height such that the sampling plate44cannot slide along the guide rails54over the piling area26, i.e. the jogger38blocks the movement of the sampling plate44. This position of the jogger38is termed working position.

The device20further comprises a sensor55which can detect the position of the sampling plate44. The sensor55can be a light barrier.

FIG.3shows a perspective view of the jogger38in more detail. As illustrated inFIG.3by double-arrow J, the jogger38can be moved back and forth towards and from the piling area26.

Additionally, the jogger38can be moved up and down as illustrated by double-arrow K inFIG.3to switch from the working position into a sampling position in which the jogger38no longer blocks the movement of the sampling plate44along the guide rails54.

The jogger38can be moved along directions J and K by drive elements56which are cylinders with electrically driven pistons. The jogger38can also have separate drive elements56for the respective motions along directions J and K.

FIG.4shows one of the lateral joggers52in more detail. The lateral jogger52can be moved sideways along the directions illustrated by double-arrow L and up and down along the directions illustrated by double-arrow M.

FIG.5shows a cross-section along the center of the extension direction of the lateral jogger52ofFIG.4.

The drive element56of the lateral jogger52comprises two cylinders58and60, one with a piston62moving along the direction L and a second one with a piston64moving along the direction M. The pistons62,64can both be driven electrically, pneumatically or hydraulically. The pistons62,64can also use different drive mechanisms.

The lateral joggers52also can be adjusted into a working position in which the movement of the sampling plate44along the guide rails54is blocked by the lateral joggers52and into a sampling position in which the lateral jogger52no longer blocks the movement of the sampling plate38along the guide rails54.

In the following, the mode of operation of the device20will be described with reference toFIGS.6and7which show perspective views of a cross-section along plane A-A shown inFIG.2.

During default operation of the converting machine10, sheets22will be processed and delivered by the transfer mechanism28to the piling area26.

The jogger38, the back jogger39and the lateral joggers52are used to align the sheets22delivered to the piling area26.

The sampling plate44is in the access position in which it partially extends from the housing40outwards. Accordingly, the sampling plate44is outside of the path of the sheets22towards the piling area26.

The operator of the converting machine10can observe the sheets22arriving at the piling area26through the window42. If the operator decides to take sample sheets, e.g. for checking the quality of the processed sheets22, he can start a sampling procedure by pressing a sampling button which is one of the control elements50of the display unit46.

This stops the transfer mechanism28from delivering new sheets22to the piling area26for a pre-selected time period t1, e.g. for 1 to 3 seconds.

Further, the jogger38and the lateral joggers52are moved downwards into their sampling positions by their respective drive elements56so that the guide rails54are no longer blocked.

Then, the display unit46gives the operator a signal that the sampling plate44can be moved into the sampling position. The signal can be given visually on the display48or acoustically by means of a (not shown) loudspeaker.

The sampling plate44can then be pushed through the opening43by the operator by means of handles45until the sampling plate44covers the piling area26(shown inFIG.7). The sampling plate44could also be moved by a (not shown) drive.

Alternatively, the jogger38and the lateral joggers52could also automatically change to their respective sampling positions as soon as the sensor55detects that the sampling plate44is moved out of its access position.

After the time period t1, the transfer mechanism28delivers a pre-defined number of sheets22into the device20. As the piling area26is now covered by the sampling plate44, these sheets22are collected on the sampling plate44.

The number of sheets22can be a set number based on the desired amount of sample sheets and/or the total height of the collected sample sheets on the sampling plate. The pre-defined number of sheets22can also be manually entered or adjusted by the operator with the display unit46.

The number of sheets22must be small enough to allow movement of the sampling plate44and the collected sample sheets through the opening43.

After the pre-defined number of sample sheets have been collected, the transfer mechanism28again stops delivering sheets22for a pre-determined time period t2.

The time periods t1and t2can have the same length or different lengths and can be adjusted and/or chosen by the operator independently of each other.

During the time period t2, the operator can move the sampling plate44back to the access position, thereby removing the collected sample sheets from the housing40.

After the time period t2, the jogger38and the lateral joggers52are moved back to their working positions and the transfer mechanism28again starts to deliver processed sheets22to the piling area26.

The operator can easily pick up the sample sheets from the sampling plate44outside of the housing40while the converting machine again starts to run.

Accordingly, the device20allows reducing downtime of the converting machine10and provides an easier way for collecting sample sheets.