Patent Description:
Additionally, the invention relates to a sheet material processing machine comprising at least two such sheet material processing units.

Known are transport systems that use dedicated grasping or clamping mechanisms, and are used to carry material to be processed according to different processing paths, where some of the sample follow one path, and some other samples follow a different path (<CIT>, <CIT>, <CIT>). Different paths are followed, by grabbing the sheets only once. In particular for avoiding damages or for avoiding losing the register (<CIT>) or having a handover mechanism from one station of the next that is independent from the sample shape (<CIT>).

Sheet material processing units and corresponding sheet material processing machines are known in the art.

In this context, the sheet material processing machine is for example a hot-foil-stamping machine. Such a machine comprises sheet material processing units related to hot-foil application by a platen and sheet delivery. Alternatively, the sheet material processing machine is a die-cutting machine comprising sheet material processing units related to cutting, waste ejection and blank separation. The invention however is not limited to these types of machines.

In order to make a sheet material travel through the different units of the machine, a transport system is provided. Often this transport system comprises a chain drive or belt drive substantially extending over all units of the machine. Consequently, a sheet material to be processed is connected to the transport system at an input end of the sheet material processing machine and at least a part of the sheet material released from the transport system at an output end of the sheet material processing machine after having been processed.

Such sheet material processing machines are efficient in performing a certain number of predefined process steps. Modifying the number or the nature of these steps implies profound modifications of the machine.

The problem to be solved by the present invention therefore is to make sheet material processing machines more flexible. Of course, the high level of efficiency and productivity of such machines shall be maintained.

The problem is solved by a sheet material processing unit, comprising an input end where sheets to be processed enter the sheet material processing unit, and an output end where at least parts of the sheets leave the sheet material processing unit, a transport system for transporting the sheets or parts thereof from the input end to the output end, and a gripper unit being releasably coupled to the transport system and being configured for holding at least a part of one of the sheets. Additionally, the input end and/or the output end are/is equipped with a handover mechanism being configured for decoupling the gripper unit from the transport system and providing the gripper unit to a neighboring sheet material processing unit and/or receiving a gripper unit from a neighboring sheet material processing unit and coupling the received gripper unit to the corresponding transport system. In contrast to known sheet material processing machines, each sheet material processing unit comprises a proprietary transport system. These transport systems may be selectively interconnected by handover mechanisms. Consequently, such sheet material processing units are self-contained modules which may be freely combined to form a sheet material processing machine. Thus, the number of modules and the corresponding process steps performed by the modules can be easily adapted. Compared to a known transport system of a known sheet material processing machine, the transport system of the sheet material processing unit is smaller and less complex. Additionally, its weight and inertia are reduced. A further advantage lies in the fact that several sheet material processing units may be produced and tested in parallel or separately before being assembled to form a sheet material processing machine.

The basic idea of the invention is to replace known transport systems spanning over all processing units of known sheet material processing machines by smaller transport systems being proprietary to each sheet material processing unit. These transport systems are interconnectable. To this end the corresponding gripper units are releasably connected thereto. Consequently, the gripper units can be handed over from one sheet material processing unit to a neighboring sheet material processing unit.

The fact that the transport system is adapted for transporting sheets or parts thereof and that the gripper unit is configured for holding at least a part of the sheet is due to the situation that a sheet entering the sheet material processing unit may be separated into several parts during its processing. In principle, three alternatives may be imagined. In a first alternative the sheet enters and leaves the sheet material processing unit without being separated into parts. Alternatively, the sheet entering the sheet material processing machine is separated into a first part and a second part during its processing. The first part may correspond to a desired result of the process, e.g. a product or intermediate product, and the second part may be waste. Thus, in a second alternative, the gripper unit may be configured for holding the first part, i.e. the product or intermediate product, wherein in a third alternative the gripper unit may be configured for holding the second part, i.e. the waste. In summary, the sheet material processing unit according to the invention is configured for all mentioned alternatives.

The sheet material processing unit may be adapted for processing sheet material in the form of cardboard, paper, plastic or wood.

The gripper unit may be coupled to the transport system via a clip-on mechanism, especially wherein the transport system comprises one or more male clip elements and the gripper unit comprises one or more corresponding female clip elements. Such a gripper unit may be easily and quickly disconnected from one transport system and connected to another transport system, e. the transport system of a neighboring sheet material processing unit. This process may be automated. Furthermore, the clip-on mechanism allows for positioning the gripper on the transport system in a precise and stable manner.

In an alternative the gripper unit is coupled to the transport system via a clamping mechanism, wherein the gripper unit comprises at least one switchable clamp being configured for selectively engaging the transport system of the sheet material processing unit and/or the transport system of a neighboring sheet material processing unit. The switching of the clamp may be performed automatically in that an actuating cam operates the clamping mechanism. This may be performed quickly. Consequently, the clamping mechanism allows for an easy and reliable handover of the gripper units between two neighboring sheet material processing units. In this context, the gripper unit and the transport systems may be configured such that clamping is only possible at designated locations of the transport systems. Alternatively, the gripper unit and the transport systems may be configured such that the gripper unit may be coupled to the transport systems at any suitable location thereof.

According to an embodiment the transport system comprises a processing section configured for transporting gripper units holding sheets or parts thereof for being processed in a direction from the input end to the output end. Thereby the processing section is associated with a handover mechanism arranged on the input end and being configured for receiving a gripper unit from a neighboring sheet material processing unit and coupling the received gripper unit to the corresponding transport system. Additionally or alternatively the processing section is associated with a handover mechanism arranged on the output end and being configured for decoupling the gripper unit from the transport system and providing the gripper unit to a neighboring sheet material processing unit. Consequently, gripper units carrying sheet material or parts thereof to be processed may arrive at the input end of the sheet material processing unit. The gripper units are then connected to the corresponding transport system via the handover mechanism. Subsequently, the sheet material or parts thereof may undergo one or more process steps performed by the sheet material processing unit. Then the gripper unit and the sheet material or parts thereof will arrive at the output end and will be transferred to a neighboring sheet material processing unit performing subsequent processing steps in that the gripper unit is released from the transport system and connected to the transport system of the neighboring sheet material processing unit. Thus, the sheet material processing unit is a flexible module which can easily be connected with other modules in order to process sheet material.

The sheet material processing unit can be a feeder unit, preferably including a registration module, a platen press unit, especially a hot foil stamping unit or a die-cutting unit, a stripping unit a waste ejection unit, a blank separation unit, a quality control unit, a digital printing unit, a digital embellishment unit, a digital cutting unit, a creasing unit or a delivery unit. Thus the sheet material processing unit can be adapted for performing any kind of processing steps related to sheet material processing.

In a variant the sheet material processing unit is a transition unit being configured for connecting two sheet material processing units being used for processing sheet material. The transport system of the transition unit comprises a transition section configured for transporting gripper units holding sheets or parts thereof in a direction from the input end to the output end. Additionally, the transition section is associated with a handover mechanism arranged on the input end and being configured for receiving a gripper unit from a neighboring sheet material processing unit and coupling the received gripper unit to the corresponding transport system. Moreover, the transition section is associated with a handover mechanism arranged on the output end and being configured for decoupling the gripper unit from the transport system and providing the gripper unit to a neighboring sheet material processing unit. In other words the sheet material processing unit being configured as a transition unit may be used for connecting two sheet material processing units which are used for treating sheet material. The transition unit as such is not configured for performing process steps other than transporting sheets or parts thereof. The purpose of a transition unit is rather to make sheet material processing units compatible, i.e. connect sheet material processing units wherein a handover mechanism at an output end of one of the sheet material processing units may not be directly connectable to a handover mechanism at an input end of another one of the sheet material processing units. If the transition unit is used, a gripper unit may be transferred from one sheet material processing unit to the transition unit and from there to another sheet material processing unit. In this context the handover mechanisms at the input end and the output end of the transition unit may be of different design. Consequently, the transition unit can be used as an adapter unit. Alternatively or additionally, the transition unit may be simply used for bridging a certain distance between two sheet material processing units.

According to the invention, the transport system comprises a recirculation section configured for transporting gripper units without sheets in a direction from the output end to the input end. Thereby preferably, the recirculation section is associated with a handover mechanism arranged on the output end and being configured for receiving a gripper unit from a neighboring sheet material processing unit and coupling the received gripper unit to the corresponding transport system. According to the invention, the recirculation section is associated with a handover mechanism arranged on the input end and being configured for decoupling the gripper unit from the transport system and providing the gripper unit to a neighboring sheet material processing unit. In other words, the sheet material processing unit is able to recirculate empty gripper units from an output end to an input end thereof. These gripper units may then be used for processing additional sheet material. In doing so, the gripper units circulate in a closed loop. This is efficient in that only a predefined number of gripper units is needed and in that the recirculation is done in a fully automatic manner.

Preferably, the transport system comprises a belt drive or a chain drive, wherein the gripper unit is releasably coupled to a corresponding belt or chain. Belt drives and chain drives have proven to be suitable for sheet material processing units. They are reliable and precise in operation.

The problem is also solved by a sheet material processing machine as mentioned above which comprises at least two neighboring sheet material processing units according to the invention. The sheet material processing units are coupled by a first handover mechanism being provided at an output end of a first sheet material processing unit and being configured for decoupling the gripper unit from the corresponding transport system and providing the gripper unit to a second sheet material processing unit and a second handover mechanism being provided at an input end of the second sheet material processing unit and being configured for receiving the gripper unit from the first sheet material processing unit and coupling the received gripper unit to a corresponding transport system. In this context both of the at least two sheet material processing units may actually perform a process step on the sheet material to be processed. Alternatively, one of the at least two sheet material processing units is a transition unit and only the other one of the at least two sheet material processing units performs a process step. Thus, such a sheet material processing machine is highly flexible in that depending on the process to be performed, sheet material processing units may be easily combined and connected by the corresponding handover mechanisms. It is also possible to eliminate process steps by eliminating the corresponding sheet material processing unit and reconnecting the remaining sheet material processing units by their handover mechanisms.

In a configuration in which one of the at least two sheet material processing units of the sheet material processing machine is a transition unit, preferably a third sheet material processing unit is provided which is configured for performing a process step on the sheet material. The transition unit is advantageously located in between the sheet material processing units performing process steps on the sheet material. In doing so the transition unit may operate as an adapter unit as has already been described before. Consequently, sheet material processing units may be freely and flexibly combined.

The two neighboring sheet material processing units may be coupled by a third handover mechanism being provided at an input end of the second sheet material processing unit and being configured for decoupling the gripper unit from the corresponding transport system and providing the gripper unit to the first sheet material processing unit and by a fourth handover mechanism being provided at an output end of the first sheet material processing unit and being configured for receiving the gripper unit from the second sheet material processing unit and coupling the received gripper unit to a corresponding transport system. This applies to sheet material processing units actually performing process steps and also to sheet material processing units being transition units. Thus, gripper units may be recirculated to an input end of the sheet material processing machine after they have been served for holding sheet material. The gripper units may thus be operated in a closed loop.

Alternatively, a recirculation module may be provided comprising a transport system for transferring gripper units from an output end of the second sheet material processing unit to an input end of the first sheet material processing unit. In this alternative the gripper units are not recirculated via the sheet material processing units but via a separate recirculation module spanning from an output end of the sheet material processing machine to an input end thereof. Thus, the sheet material processing units may be operated as if they were used in an open-loop configuration. Due to the recirculation module, the sheet material processing machine as such may be operated in a closed loop.

Recirculation modules are especially advantageous for sheet material processing units transporting the gripper units with the sheets or parts thereof at a speed variable over time. In this context, the gripper units and corresponding sheets or parts thereof may be regularly accelerated or decelerated. The movement of the gripper units and the corresponding sheets or parts thereof may also be regularly stopped. Such a mode of operation may be called a stop-and-go mode. However, the recirculation modules may operate continuously, i.e. transporting the gripper units and corresponding sheets or parts thereof at substantially constant speed. In this configuration the sheet material processing units experience reduced inertia when accelerating or decelerating gripper units and corresponding sheets or parts thereof since the gripper units being in the course of recirculation are decoupled therefrom. This allows for operating the sheet material processing units at high speed and/or high accelerations. Additionally, high quality process results are assured.

The sheet material processing machine may also comprise a gripper exchange module which may be coupled to a recirculation section of at least one of the sheet material processing units or the recirculation module. The gripper exchange module is configured for withdrawing gripper units from the recirculation section or the recirculation module and/or for feeding gripper units into the recirculation section or the recirculation module. Thus, the gripper exchange module may be used for exchanging gripper units needing to undergo maintenance or needing replacement. Moreover, the gripper exchange module may be used for increasing or decreasing the number of gripper units being used in the sheet material processing machine. Consequently, the gripper exchange module facilitates adaptation of the sheet material processing machine to different jobs needing different numbers of gripper units. The gripper exchange module may operate while sheet material is processed by the sheet material processing machine and especially by the sheet material processing units. Consequently, the gripper exchange module may perform its functions without the need for stopping the process in the sheet material processing machine.

The gripper exchange module may be equipped with an input buffer in which a number of gripper units may be stored. Consequently, gripper units are held available for replacing or complementing the gripper units in the sheet material processing machine. Thus, the replacing or complementing may be performed within a very restricted time frame.

Advantageously, the transport system of the first sheet material processing unit comprises a first transport wheel being arranged at the output end thereof and the transport system of the second sheet material processing unit comprises a second transport wheel being arranged at the input end thereof, wherein the first transport wheel and the second transport wheel are substantially arranged coaxially. In this configuration the handover of the gripper units may be performed quickly in that the first transport wheel actuates a release mechanism disconnecting the gripper unit from the transport system of the first sheet material processing unit and the second transport wheel actuates a locking mechanism connecting the gripper unit to the transport system of the second sheet material processing unit. This solution is also space-saving.

In another embodiment the transport system of the first sheet material processing unit overlaps the transport system of the second sheet material processing unit in a processing direction. The area where the transport system overlap may be called a transition zone. In this area the griper unit will be coupled with the transport system of the second sheet material processing unit and decoupled from the transport system of the first sheet material processing unit. Preferably, the gripper unit will be connected to the transport system of the second sheet material processing unit before it is released from the transport system of the first sheet material processing unit. In doing so, the gripper unit is always in a well defined position.

According to a preferred variant the transport system of the first sheet material processing unit and the transport system of the second sheet material processing unit comprise a control unit respectively such that the transport systems are controllable independently from one another. This allows for example for independent error handling in the respective sheet material processing units. Especially positioning errors of the sheet material to be processed may be easily corrected. Additionally, the independent control units make it possible to combine sheet material processing units relying on different operational speeds. It is also possible to connect sheet material processing unit which operate at constant speed, e.g. feeding or discharging units, with sheet material processing units operating in a stop-and-go-mode, e.g. platen or stripping units. It is noted that for ensuring a smooth transition between two independently controllable sheet material processing units, the sheet material processing units need to be synchronized only during the transition of the gripper unit from one transport system to the neighboring one. For example, if the first unit is operating in a stop-and-go-mode, and the second operates at constant speed, only during the relatively short period of time during which the gripper handed over from one transport system to the neighboring transport system, both transport system need to run at the same speed.

The sheet material processing machine may be a platen press, especially a hot-foil stamping machine, or a die-cutting machine.

The invention will now be described with reference to the enclosed drawings. In the drawings,.

<FIG> shows a sheet material processing machine <NUM> according to a first embodiment not according to the invention, which is a die-cutting machine.

It is adapted for processing sheets <NUM> being provided on an entering pile <NUM> and being placed on an exiting pile <NUM> after having been processed.

Following a processing direction <NUM> of the sheets <NUM> through the sheet material processing machine <NUM> it comprises a total of five sheet material processing units <NUM> to <NUM>.

In the present example, sheet material processing unit <NUM> is a feeder unit, sheet material processing unit <NUM> is a platen press unit, sheet material processing unit <NUM> is a stripping unit, sheet material processing unit <NUM> is a quality control unit and sheet material processing unit <NUM> is a delivery unit.

In the following, the feeder unit will be designated with reference sign <NUM>, the platen press unit will be designated with reference sign <NUM>, the stripping unit will be designated with reference sign <NUM>, the quality control unit will be designated with reference sign <NUM> and the delivery unit will be designated with reference sign <NUM> for the ease of explanation.

Furthermore, a recirculation module <NUM> is provided.

Each of the sheet material processing units <NUM> to <NUM> comprises an input end, respectively designated 20i, 22i, 24i, 26i, 28i, where sheets <NUM> to be processed enter the respective sheet material processing unit <NUM> to <NUM> and an output end, respectively designated 20o, 22o, 24o, 26o, 28o, where the sheets <NUM> leave the respective sheet material processing unit <NUM> to <NUM>.

The feeder unit <NUM>, the platen press unit <NUM>, and the stripping unit <NUM> are equipped with a respective transport system <NUM> for transporting the sheets <NUM> from the respective input end 20i, 22i, 24i to the respective output end 20o, 22o, 24o.

Each transport system <NUM> comprises a first transport wheel <NUM> being arranged at the output end 20o, 22o, 24o of the corresponding sheet material processing unit <NUM>, <NUM>, <NUM> and a second transport wheel <NUM> being arranged at the input end 20i, 22i, 24i of the corresponding sheet material processing unit <NUM>, <NUM>, <NUM>.

The transport wheels <NUM>, <NUM> interact with a belt <NUM> being driven and/or guided by the respective transport wheels <NUM>, <NUM>.

The recirculation module <NUM> also comprises a transport system <NUM> which is equipped with a belt <NUM> that is driven and/or guided by a plurality of associated transport wheels <NUM>.

In the example shown in <FIG> the transport system <NUM> is a shared transport system in the sense that it is also used for the quality control unit <NUM> and the delivery unit <NUM>. In other words, the quality control unit <NUM> and the delivery unit <NUM> do not have a separate transport system such as the feeder unit <NUM>, the platen press unit <NUM> and the stripping unit <NUM>.

All transport systems <NUM> are adapted for transporting sheets <NUM> from the respective input end 20i, 22i, 24i to the respective output end 20o, 22o, 24o.

Since the sheets <NUM> do not directly interact with the transport systems <NUM>, <NUM>, gripper units <NUM> are provided which are adapted for holding the sheet <NUM>.

The gripper units <NUM> may be coupled to the transport systems <NUM>, <NUM>.

It is to be understood that the number of gripper units <NUM> used in a specific sheet material processing machine <NUM> may vary depending on the job to be performed.

In <FIG> only two gripper units <NUM> are shown, which is rather due to the ease of representation than to technical requirements.

The sheets <NUM> to be processed are gripped by the gripper unit <NUM> in the feeder unit <NUM> and released in the delivery unit <NUM>.

The transport system <NUM> is adapted for transporting gripper units <NUM> without sheets <NUM> from the output end 24o of the stripping unit <NUM> to the input end 20i of the feeder unit <NUM>.

Consequently, the gripper units <NUM> are operated in a closed loop.

Therefore, the gripper units <NUM> need to be transferred from one transport system <NUM>, <NUM> to a respective neighboring transport system <NUM>, <NUM>.

In order to do so, the gripper units <NUM> are releasably coupled to the transport systems <NUM>, <NUM>, more precisely to the corresponding belts <NUM>, <NUM>.

Moreover, each of the input ends 20i, 22i 24i, 26i comprise a handover mechanism 47r being configured for receiving a gripper unit <NUM> from a neighboring sheet material processing unit <NUM> to <NUM> or the recirculation module <NUM> and coupling the received gripper unit <NUM> to the respective transport system <NUM>, <NUM>.

In this context, the input end 26i of the quality control unit serves as an input end 30i of the recirculation module <NUM>.

The output ends 20o, 22o, 24o, 30o are equipped with a handover mechanism 47d which is configured for decoupling the gripper unit <NUM> from the respective transport system <NUM>, <NUM> and providing the gripper unit <NUM> to a neighboring sheet material processing unit <NUM> to <NUM> or the recirculation module <NUM>.

The zones where the handing over of the gripper units <NUM> happens are called transition zones <NUM>.

In more detail, the feeder unit <NUM> comprises a handover mechanism 47d being provided in the transition zone <NUM> associated with its output end 20o and being configured for decoupling the gripper unit <NUM> from the transport system <NUM> and providing the gripper unit <NUM> to the transport system <NUM> of the platen press unit <NUM>.

Moreover, the feeder unit <NUM> comprises a handover mechanism 47r being provided in the transition zone <NUM> associated with its input end 20i and being configured for receiving the gripper unit <NUM> without carrying a sheet <NUM> from the recirculation module <NUM> and coupling the received gripper unit <NUM> to its transport system <NUM>.

Thus, the feeder unit <NUM> in total comprises two handover mechanisms 47d, 47r.

The platen press unit <NUM> comprises a handover mechanism 47r being provided in the transition zone <NUM> associated with its input end 22i and being configured for receiving the gripper unit <NUM> carrying a sheet <NUM> from the feeder unit <NUM> and coupling the received gripper unit <NUM> to its transport system <NUM>.

Additionally, the platen press unit <NUM> comprises a handover mechanism 47d being provided in the transition zone <NUM> associated with its output end 22o and being configured for decoupling the gripper unit <NUM> from the transport system <NUM> and providing the gripper unit <NUM> to the transport system <NUM> of the stripping unit <NUM>.

Thus, also the platen press unit <NUM> comprises a total of two handover mechanisms 47r, 47d.

The same applies to the stripping unit <NUM> to which the above explanations apply mutatis mutandis.

The transport system <NUM> of the recirculation module <NUM>, which is also shared by the quality control unit <NUM> and the delivery unit <NUM> comprises a handover mechanism 47r being provided in the transition zone <NUM> associated with its input end 26i, 30i and being configured for receiving the gripper unit <NUM> carrying a sheet <NUM> from the stripping unit <NUM> and coupling the received gripper unit <NUM> to its transport system <NUM>.

Furthermore, a handover mechanism 47d is provided in the transition zone <NUM> associated with its output end 30o and being configured for decoupling the gripper unit <NUM> from the transport system <NUM> and providing the gripper unit <NUM> to the transport system <NUM> of the feeder unit <NUM>.

Thus, the shared transport system <NUM> of the recirculation module <NUM> comprises two handover mechanisms 47d, 47r.

The handover mechanisms 47r, 47d and the transition zones <NUM> will be explained below in connection with <FIG>.

Each of the transport systems <NUM> of the sheet material processing units <NUM> to <NUM> and the transport system <NUM> of the recirculation module <NUM> comprises a respective control unit <NUM>.

The control units <NUM> are adapted for controlling the movement of the respective belt <NUM>, <NUM>. In doing so, a position and a movement of a gripper unit <NUM> being coupled to the respective belt <NUM>, <NUM> can be precisely controlled.

The control units <NUM> are independent from each other and thus make it possible to operate some of the transport systems <NUM>, <NUM> in a continuous manner, i.e. the corresponding belts <NUM>, <NUM> travel at a substantially constant speed.

In the example shown this is the case for the feeder unit <NUM> and the recirculation module <NUM>.

It is also possible to operate other transport systems <NUM>, <NUM> in a stop-and-go-mode, i.e. the corresponding belts <NUM>, <NUM> are intermittently accelerated to a predetermined travel speed and then stopped.

In the example of <FIG> this is the case for the platen press unit <NUM> and the stripping unit <NUM>.

In <FIG> a sheet material processing machine <NUM> according to a second embodiment is shown.

In the following only the differences to the sheet material processing machine <NUM> according to the first embodiment will be explained. Equal or corresponding parts will be designated with the same reference signs.

The sheet material processing machine <NUM> of <FIG> is also a die-cutting machine and comprises a feeder unit <NUM>, a platen press unit <NUM>, a stripping unit <NUM>, a quality control unit <NUM> and a delivery unit <NUM>.

Again, the sheet material processing units <NUM> to <NUM> are equipped with a transport system <NUM>.

In contrast to the first embodiment, no recirculation module is provided. Instead, the quality control unit <NUM> and the delivery unit <NUM> share a transport system <NUM>.

The sheet material processing machine <NUM> according to the second embodiment further differs from the sheet material processing machine <NUM> according to the first embodiment in that the recirculation of gripper units <NUM> without sheets <NUM> takes place via the transport systems <NUM> of the sheet material processing units <NUM> to <NUM>.

In this context, the transport systems <NUM> may be subdivided into a processing section 32p and a recirculation section 32r respectively.

The processing sections 32p are configured for transporting gripper units <NUM> holding sheets <NUM> for being processed in a processing direction <NUM>, i.e. from a respective input end 20i, 22i, 24i, 26i to a respective output end 20o, 22o, 24o.

The processing sections are associated with respective handover mechanisms 47r, 47d which are arranged in transit zones <NUM> and substantially correspond to the handover mechanisms 47r, 47d as explained with respect to the first embodiment.

The recirculation sections 32r are configured for transporting gripper units <NUM> without sheets <NUM> in a direction from a respective output end 28o, 26o, 24o, 22o, 20o to a respective input end 20i, 22i, 24i, 26i, 28i.

To this end, also the recirculation sections 32r are provided with handover mechanisms 47r, 47d which are arranged in corresponding transit zones <NUM>.

The handover mechanisms 47r, 47d of the recirculation sections 32r substantially correspond to the handover mechanisms 47r, 47d of the processing sections 32p and will be explained in detail in connection with <FIG> below.

Consequently, the feeder unit <NUM> comprises a handover mechanism 47d being provided in the transition zone <NUM> associated with its output end 20o and being configured for decoupling the gripper unit <NUM> from the transport system <NUM> and providing the gripper unit <NUM> to the transport system <NUM> of the platen press unit <NUM>.

Additionally, the feeder unit <NUM> comprises a handover mechanism 47r being provided in the transition zone <NUM> associated with its output end 20o and being configured for receiving the gripper unit <NUM> without carrying a sheet <NUM> from the platen press unit <NUM> and coupling the received gripper unit <NUM> to its transport system <NUM>.

Moreover, the platen press unit <NUM> comprises a handover mechanism 47d being provided in the transition zone <NUM> associated with its output end 22o and being configured for decoupling the gripper unit <NUM> from the transport system <NUM> and providing the gripper unit <NUM> to the transport system <NUM> of the stripping unit <NUM>.

Additionally, platen press unit <NUM> comprises a handover mechanism 47r being provided in the transition zone <NUM> associated with its output end 22o and being configured for receiving the gripper unit <NUM> not carrying a sheet <NUM> from the stripping unit <NUM> and coupling the received gripper unit <NUM> to its transport system <NUM>.

The platen press unit <NUM> comprises a further handover mechanism 47d being provided in the transition zone <NUM> associated with its input end 22i and being configured for decoupling the gripper unit <NUM> from the transport system <NUM> and providing the gripper unit <NUM> to the transport system <NUM> of the feeder unit <NUM>.

Thus, the platen press unit <NUM> in total comprises four handover mechanisms 47r, 47d.

The shared transport system <NUM> of the quality control unit <NUM> and the delivery unit <NUM> comprises a handover mechanism 47r being provided in the transition zone <NUM> associated with its input end 26i and being configured for receiving the gripper unit <NUM> carrying a sheet <NUM> from the stripping unit <NUM> and coupling the received gripper unit <NUM> to its transport system <NUM>.

Furthermore, a handover mechanism 47d is provided in the transition zone <NUM> associated with its input end 26i and being configured for decoupling the gripper unit <NUM> from the transport system <NUM> and providing the gripper unit <NUM> to the transport system <NUM> of the stripping unit <NUM>.

Thus, the combination of the quality control unit <NUM> and the delivery unit <NUM> in total comprises two handover mechanisms 47d, 47r.

A sheet material processing machine <NUM> according to a third embodiment is shown in <FIG>.

In the following, only the differences to the sheet material processing machines according to the first and second embodiments will be explained. Equal or corresponding parts will be designated with the same reference signs.

The sheet material processing machine <NUM> according to the third embodiment is a hot-foil stamping machine. The platen press unit <NUM> is adapted accordingly.

In contrast to the embodiments explained above, it comprises a foil handling system <NUM> with a storage facility for foils to be processed by the platen press unit <NUM>.

The foil handling system <NUM> is arranged inside the shared transport system <NUM> of the quality control unit <NUM> and the delivery unit <NUM>.

Furthermore, the stripping unit <NUM> has been eliminated.

<FIG> and <FIG> show the transition zones <NUM>, <NUM> and the corresponding handover mechanisms 47r, 47d.

In this context, two belts <NUM> of a first transport system <NUM> and two belts <NUM> of a second transport system <NUM> are shown.

In order to differentiate the two transport systems <NUM>, elements of the first transport system will be designated with a suffix a and elements of the second transport system will be designated with a suffix b.

The first transport system 32a is for example associated to the feeder unit <NUM>, the platen press unit <NUM> or the stripping unit <NUM>.

The second transport system 32b is for example associated to the platen press unit <NUM> or the stripping unit <NUM>.

Along the processing direction <NUM> the second transport system 32b is arranged behind the first transport system 32a. Additionally, the first transport system 32a overlaps the second transport system 32b in the processing direction <NUM>.

In the state represented in <FIG> and <FIG> the gripper unit <NUM> is coupled to the first transport system 32a, more precisely to the corresponding belts 38a via a clamping mechanism <NUM>.

It comprises at least two clamps 56a, 56b. They engage the belts 38a in that the belts 38a are clamped between the respective clamps 56a, 56b and the gripping unit <NUM>.

In order to transfer the gripping unit <NUM> from the first transport system 32a to the second transport system 32b the clamps 56a, 56b are disengaged from the belts 38a. To this end the handover mechanism 47d is be used, which decouples the gripper unit <NUM> from the first transport system <NUM> and provides it to the second transport system 32b.

The handover mechanism 47d is associated with actor 57a, which may interact with the clamps 56a, 56b via cams or cammed wheels.

Subsequently, the handover mechanism 47r which is associated with the second transport system 32b receives the gripper unit <NUM> and couples it to the second transport system 32b in that the belts 38b are clamped between the respective clamps 56a, 56b and the gripping unit <NUM>.

Also the handover mechanism 47r is associated with an actor 57b, which may interact with the clamps 56a, 56b via cams or cammed wheels.

This handover procedure is illustrated by arrows 58a, 58b. Respective turning axes of the clamps 56a, 56b are designated by reference signs 60a, 60b.

Transition zones <NUM>, <NUM> with alternative handover mechanisms 47d, 47r are shown in <FIG>.

In this alternative the first transport wheel <NUM> and the second transport wheel <NUM> of neighboring transport systems <NUM> are substantially arranged coaxially.

Both a belt 38a of a first transport system 32a and a belt 38b of a second transport system 32b are equipped with male clip elements <NUM>. For the ease of representation only some of the male clip elements <NUM> are provided with a reference sign.

The gripper unit <NUM> to be transferred from the first transport system 32a to the second transport system 32b comprises female clip elements <NUM>.

In the state represented in <FIG> the male clip elements <NUM> of the first belt 38a are engaged with the female clip elements <NUM> of the gripper unit <NUM> thereby forming a clip-on mechanism <NUM>.

When travelling further in the processing direction <NUM> the male clip elements <NUM> of the first belt 38a will be disengaged from the gripper unit <NUM> by the handover mechanism 47d.

Subsequently, the gripper unit <NUM> will be transferred to the second transport system 32b and the gripper unit <NUM>, more precisely the female clip elements <NUM> provided thereon, will be engaged with the male clip elements <NUM> of the second belt 38b by the handover mechanism 47r.

<FIG> shows a gripper exchange module <NUM> which may be coupled to a recirculation section 32r of any one of the previously described sheet material processing units <NUM> to <NUM> or a recirculation unit <NUM>.

The gripper exchange module <NUM> comprises a gripper withdrawal section <NUM> which is configured for withdrawing gripper units <NUM> from the recirculation section 32r or the recirculation unit <NUM>.

Moreover, the gripper exchange module <NUM> has a feeder section <NUM> which is configured for feeding gripper units <NUM> to the recirculation section 32r or the recirculation unit <NUM>.

The feeder section <NUM> is equipped with an input buffer <NUM>, where for the ease of representation three gripper units <NUM> are stored.

The gripper exchange module <NUM> may be used for exchanging gripper units <NUM> needing replacement.

Moreover, the gripper exchange module <NUM> is configured for adapting a number of gripper units <NUM> being used in the sheet material processing machine <NUM> and, thus, for adapting the sheet material processing machine <NUM> to different jobs needing different numbers of gripper units <NUM>.

<FIG> show a sheet material processing machine <NUM> according to a fourth embodiment not according to the invention.

Again, only the differences to the sheet material processing machines <NUM> according to the embodiment described above will be explained. Corresponding parts will be designated with the same reference signs.

The sheet material processing machine <NUM> of the fourth embodiment comprises three sheet material processing units <NUM>, <NUM>, <NUM>, wherein the sheet material processing units <NUM> and <NUM> are configured for performing a process step on the sheet <NUM> to be processed. They may be of any type mentioned in the previous embodiments.

Sheet material processing unit <NUM> is a transition unit <NUM> and thus is configured for connecting the sheet material processing units <NUM>, <NUM> in terms of material flow, i.e. as far as a flow of sheets <NUM> to be processed is concerned.

The transport system <NUM> of the transition unit <NUM> comprises a transition section 32t configured for transporting gripper units <NUM> holding sheets <NUM> or parts thereof in a direction from the input end 22i to the output end 22o of the transition unit <NUM>.

The transition section 32t is associated with a handover mechanism arranged on the input end 22i and being configured for receiving a gripper unit <NUM> from sheet material processing unit <NUM> and coupling the received gripper unit <NUM> to the transport system <NUM> of the transition unit <NUM>.

Furthermore, the transition section 32t is associated with a handover mechanism arranged on the output end 22o and being configured for decoupling the gripper unit <NUM> from the transport system <NUM> of the transition unit <NUM> and providing it to sheet material processing unit <NUM>.

Both handover mechanisms are configured as in the previous embodiments. For the ease of representation they are not shown in <FIG>.

The transports system <NUM> of the transition unit <NUM> comprises four belt drives 78a, 78b, 78c, 78d.

Belt drives 78a, 78b are positioned on the same side of the sheet material processing machine <NUM> and are arranged one above the other such that a gripper unit <NUM> may be received between belt drives 78a, 78b.

Similarly, belt drives 78c, 78d are positioned on a side of the sheet material processing machine <NUM> which is opposed to the side where belt drives 78a, 78b are located. Also belt drives 78c, 78d are arranged one above the other such that a gripper unit <NUM> may be received belt drives 78c, 78d.

During the operation of the sheet material processing machine <NUM> a gripper unit <NUM> being provided by the handover mechanism at the output end 20o of the sheet material processing unit <NUM> may be received by the transport system <NUM> of the transition unit <NUM>, i.e. between belt drives 78a, 78b and belt drives 78c, 78d.

Upon actuation of the belt drives 78a to 78d, the gripper unit <NUM> and a sheet <NUM> connected therewith may be transported from the input end 22i to the output end 22o of the transition unit <NUM>.

At the output end 22o the gripper unit <NUM> and the sheet <NUM> may be provided to a handover mechanism at the input end 24i of the sheet material processing unit <NUM>.

As can for example be seen when comparing the sheet material processing machine <NUM> of the fourth embodiment to the transition zone <NUM> shown in <FIG>, the transition unit <NUM> renders sheet material processing units <NUM>, <NUM> compatible which both comprise transport systems <NUM> wherein belts <NUM> are arranged with substantially equal transversal distance. In this configuration it is not possible to arrange the belts <NUM> in an overlapping manner with respect to the processing direction <NUM>.

Claim 1:
Sheet material processing unit (<NUM> to <NUM>), comprising
an input end (20i to 28i) where sheets (<NUM>) to be processed enter the sheet material processing unit (<NUM> to <NUM>), and an output end (20o to 28o) where at least parts of the sheets (<NUM>) leave the sheet material processing unit (<NUM> to <NUM>),
a transport system (<NUM>) for transporting the sheets (<NUM>) or parts thereof from the input end (20i to 28i) to the output end (20o to 28o), and
a gripper unit (<NUM>) being releasably coupled to the transport system (<NUM>) and being configured for holding at least a part of one of the sheets (<NUM>),
wherein the input end (20i to 28i) and/or the output end (20o to 28o) are/is equipped with a handover mechanism (47d, 47r) being configured for decoupling the gripper unit (<NUM>) from the transport system (<NUM>) and providing the gripper unit (<NUM>) to a neighboring sheet material processing unit (<NUM> to <NUM>) and/or receiving a gripper unit (<NUM>) from a neighboring sheet material processing unit (<NUM> to <NUM>) and coupling the received gripper unit (<NUM>) to the corresponding transport system (<NUM>) characterized in that the transport system (<NUM>) comprises a recirculation section (32r) configured for transporting gripper units (<NUM>) without sheets (<NUM>) in a direction from the output end (20o to 28o) to the input end (20i to 28i),
wherein the recirculation section (32r) is associated with a handover mechanism (47d) arranged on the input end (20i to 28i) and being configured for decoupling the gripper unit (<NUM>) from the transport system (<NUM>) and providing the gripper unit (<NUM>) to a neighboring sheet material processing unit (<NUM> to <NUM>).