Machine for forming cardboard boxes

Abstract

The present invention relates to a machine comprising a system for transferring die-cut sheets that carries the sheets (3) from at least one loader (6) to a forming station (2) of the machine (1), so that each sheet (3) is collected from the loader (6) to be transferred to horizontal longitudinal bars (12), and then each sheet (3) is pulled to the forming station (2) of the machine (1) by means of a conveyor device (5) that is capable of maintaining the sheet (3) in the same horizontal plane during the travel thereof. The machine (1) further comprises one or more loaders (6) and one or more forming stations (2); wherein each loader (6) incorporates retention devices that complement one another to constantly keep the loader (6) with stacked sheets in order to avoid machine stops (1).

Description

Object of the invention

[0001] The present invention relates to a machine for forming cardboard boxes comprising a system for transferring die-cut sheets to transfer the sheets from at least one loader to a forming station of the machine. In this situation, each sheet is collected from the loader by means of a suction cup device that is responsible for depositing the sheet on longitudinal bars and then the sheet is pulled to the forming station of the machine by means of a conveyor device, keeping the sheet in the same horizontal plane during the travel thereof. It is also an object of the invention the machine itself comprising the transfer system, one or more loaders and one or more forming stations.Technical problem to be solved and background of the invention

[0002] Currently, machines for forming cardboard boxes are known which generally comprise a forming station that integrates a mould and a core, as well as a system for transferring the die-cut sheets, from which the boxes are assembled, such that said transfer system is responsible for handling the sheets until they are taken to the forming station.

[0003] The die-cut sheets are initially stacked in a loader, so that by means of a suction cup device the sheets are moved individually to be placed on horizontal guides to be later transferred by means of a pulling device to the forming station where each box is assembled.

[0004] Among others, machines for forming cardboard boxes as described in documents ES2644329, ES2081235, ES1280854 are known.

[0005] All these cited documents disclose good solutions but complex and ineffective when achieving very high forming speeds is required.

[0006] The last two documents cited, from the applicant itself, are clear examples of machines of the type in question, with their respective conveyor systems for die-cut sheets.Description of the invention

[0007] In order to achieve the objectives and avoid the drawbacks mentioned in the previous sections, the invention proposes a system for transferring die-cut sheets in a machine for forming cardboard boxes; the invention also relating to the machine itself.

[0008] The transfer of the sheets is carried out along at least one conveyor line from at least one loader in which the sheets are stacked to a forming station of the machine comprising at least one core and at least one mould; and wherein the transfer system unitarily collects the sheets from the loader to arrange same on longitudinal bars, and a conveyor device that unitarily pulls the sheets to the forming station.

[0009] The conveyor device comprises a frame in which there are coupled a first pair of driving pinions solidly attached to a transversal actuation shaft and a second pair of driven pinions that receive the transmission from the first pair of pinions through two parallel longitudinal chains; wherein the longitudinal bars are located above the conveyor device. Said transversal actuation shaft receives the rotary movement from a single gear motor.

[0010] In another embodiment of the transfer system, the first pair of pinions are solidly attached to respective independent actuation shafts connected separately to respective gear reduction motors; wherein the transmission to the first pair of pinions is carried out separately and independently through the two gear reduction motors.

[0011] The conveyor device further comprises at least one pulling mechanism that is attached to one of the two chains by means of a connector body; wherein the pulling mechanism comprises a vertical guide in which the connector body is coupled and guided.

[0012] The vertical guide is joined to a slider coupled to a lower guide that runs parallel along the chain below the same; wherein said lower guide is a fixed element solidly attached to the frame of the conveyor device.

[0013] An adjustable support is joined on top of the vertical guide of the conveyor device, onto which support in turn a pusher part is coupled by means of which each sheet moves when it is supported on the longitudinal bars, to the forming station.

[0014] During the mobility of the chains, the connector body is moved guided along the vertical guide carried in the lower guide, as the same time as the entire assembly of the pulling mechanism is configured to be moved pulled by the chain, the height of the adjustable support and its pusher part remaining constant.

[0015] The adjustable support of the drive mechanism has a horizontal bar configuration that can be attached in different positions on the vertical guide, while the pusher part is attached at one end of the adjustable support.

[0016] The machine for forming cardboard boxes comprises at least the system for transferring die-cut sheets, the loader and also the forming station.

[0017] The loader of the machine comprises a first retention device to hold the stack of stacked sheets on its rear face, corresponding to the last sheet, opposite to a front face of the stack that corresponds to a first sheet prepared to be collected by the suction cup device; wherein the stack of sheets is supported on a first centred longitudinal guide on which it is coupled the first retention device comprising a first linear actuator to which it is connected a first stop that is configured to retain the stack of sheets on its rear face.

[0018] The loader further comprises two second retention devices to hold the stack of stacked sheets on two opposite sides of its rear face by means of second retractable stops that are part of the second retention devices.

[0019] These second retention devices are configured to be activated during the feeding of sheets from the loader, at which time the first device is deactivated; wherein when the first retention device is activated, the second retention devices are deactivated and retracted.

[0020] Each of the second retention devices comprises a second linear actuator coupled to a support solidly attached to a side plate solidly attached to a frame of the loader; wherein a rod of the linear actuator is joined to a first end of an elongated profile guided in a gap of a body that is attached to a fixed guide solidly attached to the side plate.

[0021] The fixed guide comprises a longitudinal channel to which a slider structure is coupled to which a second end of the elongated profile is joined; wherein this second end is opposite to the first end of the elongated profile.

[0022] The second retractable stop is coupled to the slider structure by means of an articulated connection linked to a spring element, such as an elastic plate or a spring that is configured to achieve the retractable effect of said second retractable stop when it rotates in a direction to allow new sheets to enter the loader.

[0023] In one embodiment of the invention, the box forming machine comprises at least two loaders, at least two transport lines for die-cut sheets and at least two forming stations with two cores and two moulds; wherein the conveyor device includes two pulling mechanisms that are coupled, respectively, to the two chains of the conveyor device; and wherein said pulling mechanisms are located in positions offset with respect to each other, which implies that the different operations in the transfer of the sheets and the formation of the two boxes are also offset.

[0024] Due to the novel system for transferring the sheets, it is possible to substantially increase the manufacturing of the boxes, so that with the transfer system, as a first improvement of the invention, it acts, through its suction cup device, by extracting sheets from the stack of the loader or several loaders, and then the sheets are carried horizontally to the forming station or forming stations.

[0025] A second improvement is related to the first improvement and to the forming speed of the machine, which requires having effective sheet loaders in order to ensure that the sheets stacked on same are always perfectly available for the suction cup devices, and this requires that said loaders be continually fed with new stacks of sheets; wherein said second improvement relates to the assembly of the loader or the various loaders described.

[0026] It should be noted that when the suction cups access the stack of sheets to suck the first of them, said suction cups exert a certain thrust on this stack, such that it is required that somehow on the opposite side to the first sheet, where the last one is located, a force is applied that counteracts that thrust and ensures good stability of said stack of sheets during the reloading of sheets. This stated problem is solved with the retention device described.

[0027] To help better understand this specification, and as an integral part thereof, a series of figures is attached, in which the object of the invention is depicted in an illustrative and non-limiting manner.Brief description of the figures

[0028] Figure 1 shows a perspective view of a machine for forming cardboard boxes, object of the invention. The machine includes at least one loader and a system for transferring die-cut sheets. Figure 2 shows a perspective view of a conveyor device that forms part of the system for transferring die-cut sheets. Figure 2a shows an elevated view of that which is represented in figure 2. Figure 3 shows a perspective view of a loader that forms part of the machine of the invention. Figure 4 represents a perspective view of two parallel loaders, which are configured to support two groups or stacks of sheets. Figure 4a shows a perspective view of a portion of the loader with a stack of die-cut sheets. Figure 5 shows a plan view of the loader supporting a stack of stacked sheets arranged in vertical planes. Figure 6 represents a perspective view of a second retention device for provisionally holding the sheets stacked in the loader during the feeding of new sheets into said loader. Figure 6a represents an exploded perspective view of that which is represented in figure 6. Figure 7 represents a schematic view showing the different phases and devices during the transfer of each die-cut sheet until it reaches the box forming station. Description of an exemplary embodiment of the invention

[0029] Considering the numbering adopted in the figures, the machine for forming cardboard boxes 1 shown in Figure 1 comprises at least one box forming station 2 including at least one mould 41 and a core 40 located above the mould 41; wherein to form each box, the core 40 descends downward pulling a die-cut sheet 3 until it is introduced into the mould 41 in which the box is finally formed.

[0030] The machine 1 further includes the system for transferring die-cut sheets 3, from which the cardboard boxes are formed, as referred to in the preceding paragraph.

[0031] The transfer system comprises at least one suction cup device 4 and at least one conveyor device 5 arranged after the suction cup device 4.

[0032] Moreover, the machine 1 includes at least one loader 6 that is configured to support the sheets 3 that are stacked in substantially vertical planes; wherein said loader 6 integrates a first centred retention device 7 and two second lateral retention devices 8 in parallel; wherein the three devices 7, 8 are configured to hold and push the sheets 3 stacked in the loader 6 in different phases, such that when the first retention device 7 acts, the two second devices 8 are deactivated and vice versa.

[0033] The stack P of sheets 3 supported by the loader 6 includes a first sheet and a last sheet that is in contact with the first retention device 7 or with the two second retention devices 8, as will be described in detail later; wherein the first and last sheets 3 are arranged in opposite vertical planes of the stack P of sheets 3.

[0034] The first retention device 7 is conventional and is coupled to a first centred longitudinal guide 9, on which the stack P of sheets 3 rests. Said first retention device 7 comprises a first stop 10 linked to a first linear actuator 11, such as a magnetic cylinder, such that said first stop 10 is configured so that the stack P of sheets 3 rests therein by its last sheet.

[0035] The two second retention devices 8 only act during the unitary loading of new sheets 3 in the loader 6, so that when this does not occur, the first conventional retention device 7 acts, holding the stack P by its last sheet 3.

[0036] During the activation of the system for transferring sheets 3, the suction cup device 4 collects and transfers each first sheet of the stack P of sheets 7 to longitudinal bars 12, such that said suction cup device 4 is configured to unitarily transfer the sheets 3 from the loader 6 until same are resting on the longitudinal bars 12 that are located above the conveyor device 5 in a horizontal plane.

[0037] The conveyor device 5 is responsible for unitarily pulling each sheet 3 from the longitudinal bars 12 to the forming station 2 above the mould 41 and below the core 40.

[0038] The conveyor device 5 comprises a frame 13 in which a first pair of driving pinions 14 solidly attached to a transversal actuation shaft 15 and a second pair of driven pinions 16 that receive the transmission from the first pair of pinions 14 through two parallel longitudinal chains 17 are coupled; wherein the rotation of the transversal shaft 15 is carried out by means of a gear reduction motor 18.

[0039] In another embodiment of the invention, it can comprise two independent transversal actuation shafts that separately transmit their rotations to the respective first pinions 14, so that in this case two gear reduction motors 18 are included to transmit their rotary movements to the respective transverse actuation shafts.

[0040] The conveyor device 5 further comprises at least one pulling mechanism 19 which is fixed to one of the two chains 17 by means of a connector body 20.

[0041] The pulling mechanism 19 comprises a vertical guide 21 in which a runner portion 22 is coupled solidly attached to the connector body 20, so that during the mobility of the chains 17, the runner portion 22 together with the connector body 20 are moved guided along the vertical guide 21, while the entire pulling mechanism assembly 19 is moved pulled by the chain 17.

[0042] The vertical guide 21 is joined to a slider 23 coupled to a lower guide 24 that runs parallel along the chain 17 below the same; wherein said lower guide 24 is a fixed element solidly attached to the frame 13 of the conveyor device 5.

[0043] An adjustable support 25 is joined on top of the vertical guide 21, onto which support it is coupled in turn a pusher part 26 by means of which each sheet 3 moves when it is supported on the longitudinal bars 12, to the forming station 2. Said pusher part 26 is attached at one end of the adjustable support 25, and can have different shapes and widths.

[0044] The adjustable support 25 has a horizontal bar configuration that can be attached in different positions with respect to the vertical guide 21 and parallel to the chain 17.

[0045] The adjustable support 25 of the conveyor device 5 is attached to the vertical guide 21 by means of a plate 37 and screws 38 that thread into the vertical guide 21, while the adjustable support 25 has an end slot 39 through which said screws 38 pass to allow the mobility of the adjustable support 25.

[0046] Thus, the mobility of the respective chain 17 moves the pulling mechanism 19 assembly in the lower guide 24, so that said pulling mechanism 19 alternately runs along the upper and lower branch of the chain 17, keeping the movement of the pusher part 26 and of its adjustable support 25 in the same longitudinal and horizontal alignment without variation of the height thereof.

[0047] When the pulling mechanism 19 is associated with the lower branch of the chain 17, the connector body 20 is located in a lower location, while when the pulling mechanism 19 is associated with the upper branch of the chain 17, then the connector body 20 is located in a higher location along said vertical guide 21, always maintaining the adjustable support 25 and the pusher part 26 at the same height without variation.

[0048] The movement of the pusher part 26 (forward and backward) always occurs in the same line or plane but actuated by a chain 17, as in traditional systems, but with the big difference that in the latter the pusher part 26 follows the ascending and descending trajectory of the upper branch and the lower branch of the chain 17 itself as it is usually linked to one of its links, which does not occur in the present invention at hand, as described above.

[0049] As also previously mentioned, the pusher part 26 is mounted on the adjustable support 25 (to be able to position same wherever it is required depending on the format of the box). The adjustable support 25 in turn is linked to the vertical guide 21 that is movable by the pulling of the chain 17; wherein the connector body 20 is moved along the vertical guide 21.

[0050] The vertical guide 21 moves the entire pulling mechanism 19, but it is said vertical guide 21 that allows compensation for changes in height of the connector body 20 while the chain 17 produces the movement of the entire pulling mechanism 19.

[0051] Figures 2 and 2a show the entire assembly of the conveyor device 5, which can feed two forming stations 2 of the machine 1. Specifically, a first pulling mechanism 19 that is located in the rear part hooked to one of the two chains 17 in parallel, and a second pulling mechanism 19 that is located in the front part hooked to the other paired chain 17.This allows achieving alternate operation to avoid operating problems in the sense that the same operations do not coincide at the same time throughout the entire process of transferring the sheets 10 and forming the two boxes.

[0052] The operation of the machine 1 is substantially optimised by being able to effectively feed the respective stack P of sheets 3 that is located in the loader 6, so that, as previously mentioned, during said feeding, the first retention device 7 is deactivated, its first stop 10 moving backwards and stopping pushing the stack P of sheets 3, and the two second retention devices 8 are activated, which include second retractable stops 27 that push said stack 3 until the loading of new sheets 3 is completed, at which time the first retention device 7 is activated again and the two second retention devices 8 are deactivated.

[0053] As shown more clearly in Figure 6, each second retention device 8 comprises a second linear actuator 28 coupled to a support 29 solidly attached to a side plate 30 solidly attached to a frame 31 of the loader 6.

[0054] A rod of the linear actuator 28 is joined to a first end of an elongated profile 32 guided in a gap of a body 33 that is attached to a fixed guide 34 solidly attached to the side plate 30; wherein said fixed guide 34 includes a longitudinal channel 34a to which a slider structure 35 is coupled to which a second end of the elongated profile 32 is joined; wherein this second end is opposite to the first end of the elongated profile 32.

[0055] The second retractable stop 27 is coupled to the slider structure 35 by means of an articulated connection linked to a spring element, such as a helical spring 36 or an elastic plate 36'; all this to achieve the retractable effect of said second retractable stop 27 when it rotates in one direction to allow the entry of the new stack of sheets introduced into the loader 6.

[0056] When the two second retention devices 8 of each loader 6 are activated, the second retractable stops 27 are moved by means of the second linear actuators 28.

[0057] The function of the second retention devices 8 is to retain the stacked sheets 3, and more specifically, that the second retractable stops 27 allow the stacking of the sheets 3 to be kept stable with a certain tightness while new die-cut sheets 3 are being loaded in correspondence with a rear face corresponding to the last sheet of the stack P of sheets 3 that rests on the second retractable stops 27; wherein a front face corresponding to the first sheet of said stack P of sheets 3 corresponds to an area where the suction cup device 4 collects the sheets 3 to transfer them to the longitudinal bars 12 arranged above the conveyor device 5.

[0058] Therefore, each second retractable stop 27 functions as a ratchet allowing the introduction or entry of sheets 3 according to a direction C perpendicular to the stacked sheets 3 as shown in Figure 5. Said second retractable stop 27 tilts in one direction when the sheets are introduced by turning, then recovering its position by rotating in the opposite direction when the sheets 3 have been introduced in the last position in the stack P of sheets 3 by the action of the spring element 36, 36'.

[0059] The spring element 36, 36' tends to maintain said second retractable stop 27 in a stable position, so that each time the sheets 3 are introduced into the stack P of sheets 3 of the loader 6, said spring element 36, 36' is tensioned.

[0060] The clamping of the sheets 3 in the loader 6 remains stable perpendicular thereto during the loading of new sheets 3. Obviously, when the first retention device 7 acts, the tightening of the stack P of sheets 3 also remains stable.

Examples

Embodiment Construction

[0029]Considering the numbering adopted in the figures, the machine for forming cardboard boxes 1 shown in Figure 1 comprises at least one box forming station 2 including at least one mould 41 and a core 40 located above the mould 41; wherein to form each box, the core 40 descends downward pulling a die-cut sheet 3 until it is introduced into the mould 41 in which the box is finally formed.

[0030]The machine 1 further includes the system for transferring die-cut sheets 3, from which the cardboard boxes are formed, as referred to in the preceding paragraph.

[0031]The transfer system comprises at least one suction cup device 4 and at least one conveyor device 5 arranged after the suction cup device 4.

[0032]Moreover, the machine 1 includes at least one loader 6 that is configured to support the sheets 3 that are stacked in substantially vertical planes; wherein said loader 6 integrates a first centred retention device 7 and two second lateral retention devices 8 in parallel; wherein the ...

Object of the invention

[0001] The present invention relates to a machine for forming cardboard boxes comprising a system for transferring die-cut sheets to transfer the sheets from at least one loader to a forming station of the machine. In this situation, each sheet is collected from the loader by means of a suction cup device that is responsible for depositing the sheet on longitudinal bars and then the sheet is pulled to the forming station of the machine by means of a conveyor device, keeping the sheet in the same horizontal plane during the travel thereof. It is also an object of the invention the machine itself comprising the transfer system, one or more loaders and one or more forming stations.Technical problem to be solved and background of the invention

[0002] Currently, machines for forming cardboard boxes are known which generally comprise a forming station that integrates a mould and a core, as well as a system for transferring the die-cut sheets, from which the boxes are assembled, such that said transfer system is responsible for handling the sheets until they are taken to the forming station.

[0003] The die-cut sheets are initially stacked in a loader, so that by means of a suction cup device the sheets are moved individually to be placed on horizontal guides to be later transferred by means of a pulling device to the forming station where each box is assembled.

[0004] Among others, machines for forming cardboard boxes as described in documents ES2644329, ES2081235, ES1280854 are known.

[0005] All these cited documents disclose good solutions but complex and ineffective when achieving very high forming speeds is required.

[0006] The last two documents cited, from the applicant itself, are clear examples of machines of the type in question, with their respective conveyor systems for die-cut sheets.Description of the invention

[0007] In order to achieve the objectives and avoid the drawbacks mentioned in the previous sections, the invention proposes a system for transferring die-cut sheets in a machine for forming cardboard boxes; the invention also relating to the machine itself.

[0008] The transfer of the sheets is carried out along at least one conveyor line from at least one loader in which the sheets are stacked to a forming station of the machine comprising at least one core and at least one mould; and wherein the transfer system unitarily collects the sheets from the loader to arrange same on longitudinal bars, and a conveyor device that unitarily pulls the sheets to the forming station.

[0009] The conveyor device comprises a frame in which there are coupled a first pair of driving pinions solidly attached to a transversal actuation shaft and a second pair of driven pinions that receive the transmission from the first pair of pinions through two parallel longitudinal chains; wherein the longitudinal bars are located above the conveyor device. Said transversal actuation shaft receives the rotary movement from a single gear motor.

[0010] In another embodiment of the transfer system, the first pair of pinions are solidly attached to respective independent actuation shafts connected separately to respective gear reduction motors; wherein the transmission to the first pair of pinions is carried out separately and independently through the two gear reduction motors.

[0011] The conveyor device further comprises at least one pulling mechanism that is attached to one of the two chains by means of a connector body; wherein the pulling mechanism comprises a vertical guide in which the connector body is coupled and guided.

[0012] The vertical guide is joined to a slider coupled to a lower guide that runs parallel along the chain below the same; wherein said lower guide is a fixed element solidly attached to the frame of the conveyor device.

[0013] An adjustable support is joined on top of the vertical guide of the conveyor device, onto which support in turn a pusher part is coupled by means of which each sheet moves when it is supported on the longitudinal bars, to the forming station.

[0014] During the mobility of the chains, the connector body is moved guided along the vertical guide carried in the lower guide, as the same time as the entire assembly of the pulling mechanism is configured to be moved pulled by the chain, the height of the adjustable support and its pusher part remaining constant.

[0015] The adjustable support of the drive mechanism has a horizontal bar configuration that can be attached in different positions on the vertical guide, while the pusher part is attached at one end of the adjustable support.

[0016] The machine for forming cardboard boxes comprises at least the system for transferring die-cut sheets, the loader and also the forming station.

[0017] The loader of the machine comprises a first retention device to hold the stack of stacked sheets on its rear face, corresponding to the last sheet, opposite to a front face of the stack that corresponds to a first sheet prepared to be collected by the suction cup device; wherein the stack of sheets is supported on a first centred longitudinal guide on which it is coupled the first retention device comprising a first linear actuator to which it is connected a first stop that is configured to retain the stack of sheets on its rear face.

[0018] The loader further comprises two second retention devices to hold the stack of stacked sheets on two opposite sides of its rear face by means of second retractable stops that are part of the second retention devices.

[0019] These second retention devices are configured to be activated during the feeding of sheets from the loader, at which time the first device is deactivated; wherein when the first retention device is activated, the second retention devices are deactivated and retracted.

[0020] Each of the second retention devices comprises a second linear actuator coupled to a support solidly attached to a side plate solidly attached to a frame of the loader; wherein a rod of the linear actuator is joined to a first end of an elongated profile guided in a gap of a body that is attached to a fixed guide solidly attached to the side plate.

[0021] The fixed guide comprises a longitudinal channel to which a slider structure is coupled to which a second end of the elongated profile is joined; wherein this second end is opposite to the first end of the elongated profile.

[0022] The second retractable stop is coupled to the slider structure by means of an articulated connection linked to a spring element, such as an elastic plate or a spring that is configured to achieve the retractable effect of said second retractable stop when it rotates in a direction to allow new sheets to enter the loader.

[0023] In one embodiment of the invention, the box forming machine comprises at least two loaders, at least two transport lines for die-cut sheets and at least two forming stations with two cores and two moulds; wherein the conveyor device includes two pulling mechanisms that are coupled, respectively, to the two chains of the conveyor device; and wherein said pulling mechanisms are located in positions offset with respect to each other, which implies that the different operations in the transfer of the sheets and the formation of the two boxes are also offset.

[0024] Due to the novel system for transferring the sheets, it is possible to substantially increase the manufacturing of the boxes, so that with the transfer system, as a first improvement of the invention, it acts, through its suction cup device, by extracting sheets from the stack of the loader or several loaders, and then the sheets are carried horizontally to the forming station or forming stations.

[0025] A second improvement is related to the first improvement and to the forming speed of the machine, which requires having effective sheet loaders in order to ensure that the sheets stacked on same are always perfectly available for the suction cup devices, and this requires that said loaders be continually fed with new stacks of sheets; wherein said second improvement relates to the assembly of the loader or the various loaders described.

[0026] It should be noted that when the suction cups access the stack of sheets to suck the first of them, said suction cups exert a certain thrust on this stack, such that it is required that somehow on the opposite side to the first sheet, where the last one is located, a force is applied that counteracts that thrust and ensures good stability of said stack of sheets during the reloading of sheets. This stated problem is solved with the retention device described.

[0027] To help better understand this specification, and as an integral part thereof, a series of figures is attached, in which the object of the invention is depicted in an illustrative and non-limiting manner.Brief description of the figures

[0028] Figure 1 shows a perspective view of a machine for forming cardboard boxes, object of the invention. The machine includes at least one loader and a system for transferring die-cut sheets. Figure 2 shows a perspective view of a conveyor device that forms part of the system for transferring die-cut sheets. Figure 2a shows an elevated view of that which is represented in figure 2. Figure 3 shows a perspective view of a loader that forms part of the machine of the invention. Figure 4 represents a perspective view of two parallel loaders, which are configured to support two groups or stacks of sheets. Figure 4a shows a perspective view of a portion of the loader with a stack of die-cut sheets. Figure 5 shows a plan view of the loader supporting a stack of stacked sheets arranged in vertical planes. Figure 6 represents a perspective view of a second retention device for provisionally holding the sheets stacked in the loader during the feeding of new sheets into said loader. Figure 6a represents an exploded perspective view of that which is represented in figure 6. Figure 7 represents a schematic view showing the different phases and devices during the transfer of each die-cut sheet until it reaches the box forming station. Description of an exemplary embodiment of the invention

[0029] Considering the numbering adopted in the figures, the machine for forming cardboard boxes 1 shown in Figure 1 comprises at least one box forming station 2 including at least one mould 41 and a core 40 located above the mould 41; wherein to form each box, the core 40 descends downward pulling a die-cut sheet 3 until it is introduced into the mould 41 in which the box is finally formed.

[0030] The machine 1 further includes the system for transferring die-cut sheets 3, from which the cardboard boxes are formed, as referred to in the preceding paragraph.

[0031] The transfer system comprises at least one suction cup device 4 and at least one conveyor device 5 arranged after the suction cup device 4.

[0032] Moreover, the machine 1 includes at least one loader 6 that is configured to support the sheets 3 that are stacked in substantially vertical planes; wherein said loader 6 integrates a first centred retention device 7 and two second lateral retention devices 8 in parallel; wherein the three devices 7, 8 are configured to hold and push the sheets 3 stacked in the loader 6 in different phases, such that when the first retention device 7 acts, the two second devices 8 are deactivated and vice versa.

[0033] The stack P of sheets 3 supported by the loader 6 includes a first sheet and a last sheet that is in contact with the first retention device 7 or with the two second retention devices 8, as will be described in detail later; wherein the first and last sheets 3 are arranged in opposite vertical planes of the stack P of sheets 3.

[0034] The first retention device 7 is conventional and is coupled to a first centred longitudinal guide 9, on which the stack P of sheets 3 rests. Said first retention device 7 comprises a first stop 10 linked to a first linear actuator 11, such as a magnetic cylinder, such that said first stop 10 is configured so that the stack P of sheets 3 rests therein by its last sheet.

[0035] The two second retention devices 8 only act during the unitary loading of new sheets 3 in the loader 6, so that when this does not occur, the first conventional retention device 7 acts, holding the stack P by its last sheet 3.

[0036] During the activation of the system for transferring sheets 3, the suction cup device 4 collects and transfers each first sheet of the stack P of sheets 7 to longitudinal bars 12, such that said suction cup device 4 is configured to unitarily transfer the sheets 3 from the loader 6 until same are resting on the longitudinal bars 12 that are located above the conveyor device 5 in a horizontal plane.

[0037] The conveyor device 5 is responsible for unitarily pulling each sheet 3 from the longitudinal bars 12 to the forming station 2 above the mould 41 and below the core 40.

[0038] The conveyor device 5 comprises a frame 13 in which a first pair of driving pinions 14 solidly attached to a transversal actuation shaft 15 and a second pair of driven pinions 16 that receive the transmission from the first pair of pinions 14 through two parallel longitudinal chains 17 are coupled; wherein the rotation of the transversal shaft 15 is carried out by means of a gear reduction motor 18.

[0039] In another embodiment of the invention, it can comprise two independent transversal actuation shafts that separately transmit their rotations to the respective first pinions 14, so that in this case two gear reduction motors 18 are included to transmit their rotary movements to the respective transverse actuation shafts.

[0040] The conveyor device 5 further comprises at least one pulling mechanism 19 which is fixed to one of the two chains 17 by means of a connector body 20.

[0041] The pulling mechanism 19 comprises a vertical guide 21 in which a runner portion 22 is coupled solidly attached to the connector body 20, so that during the mobility of the chains 17, the runner portion 22 together with the connector body 20 are moved guided along the vertical guide 21, while the entire pulling mechanism assembly 19 is moved pulled by the chain 17.

[0042] The vertical guide 21 is joined to a slider 23 coupled to a lower guide 24 that runs parallel along the chain 17 below the same; wherein said lower guide 24 is a fixed element solidly attached to the frame 13 of the conveyor device 5.

[0043] An adjustable support 25 is joined on top of the vertical guide 21, onto which support it is coupled in turn a pusher part 26 by means of which each sheet 3 moves when it is supported on the longitudinal bars 12, to the forming station 2. Said pusher part 26 is attached at one end of the adjustable support 25, and can have different shapes and widths.

[0044] The adjustable support 25 has a horizontal bar configuration that can be attached in different positions with respect to the vertical guide 21 and parallel to the chain 17.

[0045] The adjustable support 25 of the conveyor device 5 is attached to the vertical guide 21 by means of a plate 37 and screws 38 that thread into the vertical guide 21, while the adjustable support 25 has an end slot 39 through which said screws 38 pass to allow the mobility of the adjustable support 25.

[0046] Thus, the mobility of the respective chain 17 moves the pulling mechanism 19 assembly in the lower guide 24, so that said pulling mechanism 19 alternately runs along the upper and lower branch of the chain 17, keeping the movement of the pusher part 26 and of its adjustable support 25 in the same longitudinal and horizontal alignment without variation of the height thereof.

[0047] When the pulling mechanism 19 is associated with the lower branch of the chain 17, the connector body 20 is located in a lower location, while when the pulling mechanism 19 is associated with the upper branch of the chain 17, then the connector body 20 is located in a higher location along said vertical guide 21, always maintaining the adjustable support 25 and the pusher part 26 at the same height without variation.

[0048] The movement of the pusher part 26 (forward and backward) always occurs in the same line or plane but actuated by a chain 17, as in traditional systems, but with the big difference that in the latter the pusher part 26 follows the ascending and descending trajectory of the upper branch and the lower branch of the chain 17 itself as it is usually linked to one of its links, which does not occur in the present invention at hand, as described above.

[0049] As also previously mentioned, the pusher part 26 is mounted on the adjustable support 25 (to be able to position same wherever it is required depending on the format of the box). The adjustable support 25 in turn is linked to the vertical guide 21 that is movable by the pulling of the chain 17; wherein the connector body 20 is moved along the vertical guide 21.

[0050] The vertical guide 21 moves the entire pulling mechanism 19, but it is said vertical guide 21 that allows compensation for changes in height of the connector body 20 while the chain 17 produces the movement of the entire pulling mechanism 19.

[0051] Figures 2 and 2a show the entire assembly of the conveyor device 5, which can feed two forming stations 2 of the machine 1. Specifically, a first pulling mechanism 19 that is located in the rear part hooked to one of the two chains 17 in parallel, and a second pulling mechanism 19 that is located in the front part hooked to the other paired chain 17.This allows achieving alternate operation to avoid operating problems in the sense that the same operations do not coincide at the same time throughout the entire process of transferring the sheets 10 and forming the two boxes.

[0052] The operation of the machine 1 is substantially optimised by being able to effectively feed the respective stack P of sheets 3 that is located in the loader 6, so that, as previously mentioned, during said feeding, the first retention device 7 is deactivated, its first stop 10 moving backwards and stopping pushing the stack P of sheets 3, and the two second retention devices 8 are activated, which include second retractable stops 27 that push said stack 3 until the loading of new sheets 3 is completed, at which time the first retention device 7 is activated again and the two second retention devices 8 are deactivated.

[0053] As shown more clearly in Figure 6, each second retention device 8 comprises a second linear actuator 28 coupled to a support 29 solidly attached to a side plate 30 solidly attached to a frame 31 of the loader 6.

[0054] A rod of the linear actuator 28 is joined to a first end of an elongated profile 32 guided in a gap of a body 33 that is attached to a fixed guide 34 solidly attached to the side plate 30; wherein said fixed guide 34 includes a longitudinal channel 34a to which a slider structure 35 is coupled to which a second end of the elongated profile 32 is joined; wherein this second end is opposite to the first end of the elongated profile 32.

[0055] The second retractable stop 27 is coupled to the slider structure 35 by means of an articulated connection linked to a spring element, such as a helical spring 36 or an elastic plate 36'; all this to achieve the retractable effect of said second retractable stop 27 when it rotates in one direction to allow the entry of the new stack of sheets introduced into the loader 6.

[0056] When the two second retention devices 8 of each loader 6 are activated, the second retractable stops 27 are moved by means of the second linear actuators 28.

[0057] The function of the second retention devices 8 is to retain the stacked sheets 3, and more specifically, that the second retractable stops 27 allow the stacking of the sheets 3 to be kept stable with a certain tightness while new die-cut sheets 3 are being loaded in correspondence with a rear face corresponding to the last sheet of the stack P of sheets 3 that rests on the second retractable stops 27; wherein a front face corresponding to the first sheet of said stack P of sheets 3 corresponds to an area where the suction cup device 4 collects the sheets 3 to transfer them to the longitudinal bars 12 arranged above the conveyor device 5.

[0058] Therefore, each second retractable stop 27 functions as a ratchet allowing the introduction or entry of sheets 3 according to a direction C perpendicular to the stacked sheets 3 as shown in Figure 5. Said second retractable stop 27 tilts in one direction when the sheets are introduced by turning, then recovering its position by rotating in the opposite direction when the sheets 3 have been introduced in the last position in the stack P of sheets 3 by the action of the spring element 36, 36'.

[0059] The spring element 36, 36' tends to maintain said second retractable stop 27 in a stable position, so that each time the sheets 3 are introduced into the stack P of sheets 3 of the loader 6, said spring element 36, 36' is tensioned.

[0060] The clamping of the sheets 3 in the loader 6 remains stable perpendicular thereto during the loading of new sheets 3. Obviously, when the first retention device 7 acts, the tightening of the stack P of sheets 3 also remains stable.

Examples

Embodiment Construction

[0029]Considering the numbering adopted in the figures, the machine for forming cardboard boxes 1 shown in Figure 1 comprises at least one box forming station 2 including at least one mould 41 and a core 40 located above the mould 41; wherein to form each box, the core 40 descends downward pulling a die-cut sheet 3 until it is introduced into the mould 41 in which the box is finally formed.

[0030]The machine 1 further includes the system for transferring die-cut sheets 3, from which the cardboard boxes are formed, as referred to in the preceding paragraph.

[0031]The transfer system comprises at least one suction cup device 4 and at least one conveyor device 5 arranged after the suction cup device 4.

[0032]Moreover, the machine 1 includes at least one loader 6 that is configured to support the sheets 3 that are stacked in substantially vertical planes; wherein said loader 6 integrates a first centred retention device 7 and two second lateral retention devices 8 in parallel; wherein the ...

Claims

1. A system for transferring die-cut sheets in a machine for forming cardboard boxes, wherein the transfer of the sheets (3) is carried out along at least one conveyance line from at least one loader (6) in which the sheets (3) are stacked in vertical planes, to a forming station (2) of the machine (1); and wherein the transfer system unitarily collects the sheets (3) from the loader (6) to arrange same on longitudinal bars (12); the transfer system comprising a conveyor device (5) that unitarily pulls the sheets (3) to the forming station (2); characterised in that: - the conveyor device (5) comprises a frame (13) in which a first pair of driving pinions (14) solidly attached to a transversal actuation shaft (15) and a second pair of driven pinions (16) that receive the transmission from the first pair of pinions (14) through two parallel longitudinal chains (17) are coupled; wherein the longitudinal bars (12) are located above the conveyor device (5); - the conveyor device (5) further comprises at least one pulling mechanism (19) that is attached to one of the two chains (17) by means of a connector body (20); wherein the pulling mechanism (19) comprises a vertical guide (21) in which the connector body (20) is coupled and guided; - the vertical guide (21) is joined to a slider (23) coupled to a lower guide (24) that runs parallel along the chain (17) below the same; wherein said lower guide (24) is a fixed element solidly attached to the frame (13) of the conveyor device (5); - an adjustable support (25) is joined on top of the vertical guide (21) and onto said adjustable support (25) in turn it is coupled a pusher part (26) by means of which each sheet (3) is moved when it is supported on the longitudinal bars (12) to the forming station (2); wherein during the mobility of the chains (17), the connector body (20) is moved guided along the vertical guide (21) carried in the lower guide (24), at the same time as the entire assembly of the pulling mechanism (19) is configured to be moved pulled by the chain (17), the height of the adjustable support (25) and of its pusher part (26) remaining constant.

2. The system for transferring die-cut sheets in a machine for forming cardboard boxes, according to claim 1, characterised in that the adjustable support (25) of the pulling mechanism (19) has a horizontal bar configuration that can be attached in different positions on the vertical guide (21), while the pusher part (26) is attached at one end of the adjustable support (25).

3. The system for transferring die-cut sheets in a machine for forming cardboard boxes, according to any one of the preceding claims, characterised in that the first pair of driving pinions (14) are solidly attached to a single transversal actuation shaft (15) connected to a gear reduction motor (18).

4. The system for transferring die-cut sheets in a machine for forming cardboard boxes, according to any one of the preceding claims 1 or 2, characterised in that the first pair of pinions (14) are solidly attached to respective independent actuation shafts connected separately to respective gear reduction motors (18); wherein the transmission to the first pair of pinions (14) is carried out separately and independently.

5. A machine for forming cardboard boxes, which comprises the system for transferring die-cut sheets (3) described in any one of the preceding claims, and also comprises the loader (6) that includes a first retention device (7) to hold the stack (P) of sheets (3) stacked on their rear face corresponding to the last sheet, opposite to a front face of the stack (P) that corresponds to a first sheet prepared to be collected by the suction cup device (4); wherein the stack (P) of sheets is supported on a first centred longitudinal guide (9) on which the first retention device (7) is coupled, comprising a first linear actuator (11) to which a first stop (10) is connected which is configured to retain the stack (P) of sheets on its rear face; is characterised in that the loader (6) further includes two second retention devices (8) to hold the stack (P) of stacked sheets on two opposite sides of its rear face by means of second retractable stops (27) that are part of the second retention devices (8); wherein the second retention devices (8) are configured to be activated during the feeding of sheets (3) from the loader (6), at which time the first device is deactivated; and wherein when the first retention device (7) is activated, the second retention devices are deactivated.

6. The machine for forming cardboard boxes, according to claim 5, characterised in that: - each of the second retention devices (8) comprises a second linear actuator (28) coupled to a support (29) solidly attached to a side plate (30) solidly attached to a frame (31) of the loader (6); wherein a rod of the linear actuator (28) is joined to a first end of an elongated profile (32) guided in a gap of a body (33) that is attached to a fixed guide (34) solidly attached to the side plate (30); - the fixed guide (34) comprises a longitudinal channel (34a) into which a slider structure (35) is coupled, to which a second end of the elongated profile (32) is joined; wherein this second end is opposite to the first end of the elongated profile (32).

7. The machine for forming cardboard boxes, according to one of the preceding claims 5 or 6, characterised in that the second retractable stop (27) is coupled to the slider structure (35) by means of an articulated connection linked to a spring element which is configured to achieve the retractable effect of said second retractable stop (27) when same rotates in one direction to allow the entry of new sheets into the loader (6); wherein said spring element is an element selected from a helical spring (36) and an elastic plate (36').

8. The machine for forming cardboard boxes, according to any one of the preceding claims 5 to 7, characterised in that it comprises at least two loaders (6), at least two transport lines for die-cut sheets (3) and at least two forming stations (2) with two cores (40) and two moulds (41); wherein the conveyor device (5) includes two pulling mechanisms (19), which are respectively coupled to the two chains (17) of the conveyor device (5); and wherein said pulling mechanisms (19) are located in offset positions with respect to one another, which implies that the different operations in the transfer of the sheets (3) and the formation of the two boxes are offset.

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