WRAPPING DEVICE FOR PRODUCT WRAPPING
Patent Information
- Authority / Receiving Office
- MX · MX
- Patent Type
- Patents
- Current Assignee / Owner
- AZIONARIA COSTRUZIONI MACCHINE AUTOMATICHE A C M A SPA
- Filing Date
- 2023-01-26
- Publication Date
- 2026-05-19
AI Technical Summary
Existing wrapping devices are limited in their ability to adapt to different wrapping materials and configurations, often applying inadequate closing forces or failing to synchronize the gripping and rotating moments of the gripping elements, leading to damage or inefficiencies in wrapping operations.
A wrapping device with independent electric motors for the drive bar and tubular shaft, controlled by a unit that can interpolate individual laws of motion, allowing for infinite configurations and adaptive pressure adjustment, ensuring proper closure of various wrapping materials and configurations without downtime.
Enables flexible operation with any type of wrapping material and configuration, preventing damage and waste by dynamically adjusting the gripping force and synchronization of movements, ensuring high production efficiency and quality.
Smart Images
Figure MX434537B0
Abstract
Description
WRAPPING DEVICE FOR PRODUCT WRAPPING K c N a FIELD OF INVENTION The present invention relates to a wrapping device for product wrappers, wherein such wrapping includes a fold closure or preferably a double fold closure of the wrapper. BACKGROUND OF THE INVENTION The present invention is used in the manufacturing sector, for example, in the food industry, for wrapping products, preferably confectionery products such as chocolates, sweets, sugared almonds and the like. BRIEF DESCRIPTION OF THE INVENTION Fold-over or double-fold closures are generally made from rectangular sheets of wrapping material, in the center of which a product to be wrapped is placed. The wrapping material is then folded over the product to create a tubular shape. Next, one or both ends of the wrapping material are folded over to form one or two end folds. In order to ensure repeatable wrapping and high production rates, automated devices have been developed that are capable of folding one or both ends of the wrapper to achieve the fold or double fold closure mentioned above. US patent 4539790A describes a device for double-fold wrapping sheets or the like, comprising a wheel with a continuously moving horizontal rotating axis on whose circumferential surface handling equipment is mounted, configured to hold the wrapped products in a tubular wrapper. Two folding devices act on opposite sides of the handling equipment to fold the ends of the tubular wrapper. Each folding device comprises a gripping element that can be driven to open and close in order to grasp and release one end of the tubular wrapper. The gripping element is mounted on the end of the sleeve within which a zipper bar slides. The sliding of the zipper bar in the sleeve determines the opening and closing of the gripping element.The sleeve slides along a sliding axis that approaches and retracts from the handling equipment and can be rotated around this axis. The sliding of the rack bar within the sleeve and the sliding of the sleeve along the sliding axis are achieved by means of a connection with followers inserted in cam rails within a single, rotating control body. Consequently, the sleeve can slide from inside to outside the handling equipment along with the rack bar to allow the gripping element to reach and retract from the end of the tubular wrap, and the rack bar can slide within the sleeve to open and close the gripping element. The applicant has noted that there is a growing need in the product wrapping sector to be > S κ c N able to use different wrapping materials and be able to make different folding configurations and double folds. — The applicant has verified that different wrapping materials may require different degrees of closure of the gripping element (i.e., mutual approximation between the parts of the gripping element) in order not to damage the wrapping and to ensure that it can be folded closed. The applicant has also verified that different double-fold configurations, even with the same wrapping material, may require different initial gripping and rotation moments for the two gripping elements. For example, it may be necessary to initiate the fold of one tubular end of the wrapping at a different time relative to the other tubular end. The applicant has noted that a double-fold wrapping device such as described in US4539790A is capable of making folds or double folds that are always identical to each other and of only one type of wrapping material or very similar types of wrapping materials. In fact, the applicant has verified that, following a change in the type of wrapping material, a double-fold wrapping device such as that described in US4539790A could apply an inadequate closing force on the gripping elements, i.e., insufficient to hold the tubular ends during the fold wrapping or such as to ruin the wrapping during the fold wrapping. The applicant also verified that, following a change in the double-fold configuration type, a double-fold wrapping device such as that described in US4539790A would not be able to handle many initial gripping and rotational moments of the two gripping elements. The applicant has conceived that it would be possible to design and produce control bodies with pairs of cam rails adapted to cause the gripping elements to follow a motion law suitable for a specific fold or double fold configuration, or suitable for operating on a specific type of wrapping material. By replacing the control bodies, it would be possible to reconfigure the operation of the device to work on a specific wrapping material and to produce a specific single-fold or double-fold wrap. However, the applicant has noted that, although in theory it would be possible to have any number of control bodies with respective pairs of cam rails, it would be practically impossible to have predetermined pairs of cam rails, so for any wrapping material or any fold or double fold configuration, a respective pair of cam rails is included. The applicant has also noted that, even if a control body with the appropriate cam rail pair were available to make the gripping element follow the correct motion law, replacing the control body would require significant downtime to perform the replacement, which would increase the production costs of the final product. Again, the applicant has verified that it is not always possible to predetermine with adequate precision the law of motion of the gripping element to obtain a particular double-fold configuration (and thus the exact shape of the cam paths that must cooperate, in the same control body, to reproduce such a law of motion) because > S 3k c It is often necessary to proceed with successive approximations to achieve the exact law of motion. Therefore, the present invention relates to a wrapping device for product wrappers. Preferably, a winder is provided. Preferably, the winder comprises a gripper mechanically connected to one end of a tubular shaft. Preferably, said tubular axis is rotatable around and translatable along said approach axis. Preferably, said grip is rotatable and fully transposable with said tubular shaft. Preferably, the winder comprises a drive bar, active in said grip. Preferably, the drive bar slides along a drive axis parallel to, or coinciding with, said approach axis. Preferably, said drive bar slides along said drive shaft relative to said tubular shaft and is rotatably clamped to said tubular shaft. Preferably, this grip can be opened and closed by moving the drive bar along the drive axis. Preferably, the winder comprises a first electric motor active in said drive bar to move said drive bar along the drive shaft. Preferably, the winder comprises a second active electric motor on said tubular shaft to move said tubular shaft along the approach axis. Preferably, a control unit is included that is configured to drive the first electric motor and the second electric motor. The applicant has noted that it is possible, from predetermined parameters, to reconstruct or interpolate the entire law of motion that the grip must perform in order to operate on a given type of wrapping material or a predetermined folding configuration. The applicant has also noted that the entire motion law to be performed with the grip can be broken down into the individual motion laws of the drive bar and the tubular shaft. The applicant has realized that by decoupling the actuator that drives the drive bar from the actuator that drives the tubular shaft, it is possible to give each actuator its own individual motion law. The applicant has also noticed that it is possible to use two independent electric motors to drive the drive bar and the tubular shaft, respectively, and that each of the two electric motors can receive its own individual motion law by means of commands from the control unit. The applicant has discovered that this allows individual motion laws to be implemented with each electric motor without the need for downtime, simply by giving each electric motor a specific motion law. The applicant has also discovered that the individual laws of motion that can be imparted to each electric motor are essentially infinite, thus making it possible to create an essentially infinite number of laws of > S 4r\ c N total movements for the gripper. This makes it possible to create essentially any fold configuration with essentially any type of wrapping material, clearly within the limits of the physically permissible configurations and materials. The applicant has also discovered that, by varying the torque of the electric motor associated with the drive bar, it is possible to vary the pressure exerted by the gripper on the wrapping during a wrapping operation, allowing the closing of particular wrapping materials or the creation of particular closing folds. The applicant has further discovered that during the momentary on / off oscillations of the device, it is possible to vary the movement laws of the drive bar and the tubular shaft to adapt them to the increasing (or decreasing) winding speed of the wrap, thus preventing production waste during the momentary on / off oscillations. In this description and subsequent claims, the term 'law of motion' refers to one or more relationships that describe the motion of a physical system. The physical system referred to in this description and subsequent claims is the grip (when referring to a law of motion of the grip), the tubular shaft (when referring to a law of motion of the tubular shaft), or the drive rod (when referring to a law of motion of the drive rod).For example, the law of motion can be represented by a mathematical function or diagram that describes the position of an object (i.e., the grip or its components, the drive rod or the tubular shaft) as a function of time, alternatively or in combination it can be represented by a mathematical function or diagram that describes the velocity of an object (i.e., of the grip or its components, the drive rod or the tubular shaft) as a function of time, alternatively or in combination it can be represented by a mathematical function or diagram that describes the acceleration of an object (i.e., the grip or its components, the drive rod or the tubular shaft) as a function of time. The present invention may have at least one of the preferred features described below. Such features may be present individually or in combination, unless expressly stated otherwise, in the enclosing device of the present invention. Preferably, a third active electric motor is provided on said tubular shaft to rotate said tubular shaft around the approach axis. Preferably, this control unit is configured to drive the third electric motor. Preferably, a driveshaft is provided that is connected to said third electric motor. Preferably, the impulse of the third electric motor causes the drive shaft to rotate around a drive shaft. Preferably, the drive shaft is parallel to the approach shaft. Preferably, a pinion is fitted to said transmission shaft to rotate with said transmission shaft. Preferably, a spur gear is fitted to said tubular shaft and is meshed directly or indirectly with said pinion. > S κ c N Preferably, the grip comprises a first jaw and a second jaw provided with a first toothed wheel and a second toothed wheel, respectively. Preferably, the first gear and the second gear are rotatable, together with the corresponding first and second jaws, around a fixing axis perpendicular to the drive axis. Preferably, the drive bar comprises a rack meshed with the first gear and the second gear. Preferably, a translation in a first direction of the drive bar along the drive axis results in a rotation of the first gear in a first angular direction and a rotation of the second gear in a second angular direction. Preferably, a rotation of the first gear in a first angular direction and a rotation of the second gear in a second angular direction causes the first jaw and the second jaw of the gripper to close. Preferably, a translation in a second direction, opposite to the first direction, of the drive bar along the drive axis results in a rotation of the first gear in a second angular direction and a rotation of the second gear in a first angular direction. Preferably, a rotation of the first gear in a second angular direction and a rotation of the second gear in a first angular direction result in the opening of the first jaw and the second jaw of the gripper. Preferably, said winder comprises a first fork. Preferably, this first fork is connected to a drive shaft of the first electric motor. Preferably, said first fork is clamped to said drive bar for translation along the drive axis. Preferably, said first fork is driven directly or indirectly by the first electric motor to move said drive bar along the drive shaft. Preferably, said drive bar is rotatable about said drive axis with respect to said first fork. Preferably, in a first modality, the drive shaft of the first electric motor is a rotary drive shaft. Preferably, in this case the first electric motor produces a mechanical movement in said drive shaft selectively directed in a first angular direction and a second angular direction. Preferably, in the first embodiment, said winder comprises a first control bar having a first end articulated with the first fork and a second end connected to the drive shaft of the first electric motor. Preferably, a main extension shaft of the first control rod and the drive shaft of the first electric motor are arranged perpendicular to each other. > S N c Preferably, a speed reducer is interposed between the drive shaft of the first electric motor and the first control rod, configured to transmit a lower rotational speed to the first rod relative to the rotational speed of the drive shaft of the first electric motor. Preferably, this first control rod moves the drive rod along the drive shaft. Preferably, in the first mode, the drive shaft of the first electric motor is driven to rotate in a first angular direction and to move the drive bar in a first direction along the drive shaft. Preferably, in the first mode, the drive shaft of the first electric motor is driven to rotate in a second angular direction opposite to the first and to move the drive bar in a second direction along the drive shaft. Preferably, in a second embodiment, the first electric motor is a linear electric motor and comprises a movable drive shaft. Preferably, the linear electric motor produces a force on said movable drive shaft directed selectively in a first direction and in a second direction. Preferably, said movable drive axis is parallel to the drive axis of the drive bar. Preferably, in the second mode, said drive shaft of the first electric motor is driven to move the drive bar in a first direction along the drive shaft. Preferably, in the second mode, said drive shaft of the first electric motor is driven to move the drive bar in a second direction along the drive shaft. Preferably, said winder comprises a second fork. Preferably, this second fork is connected to a drive shaft of the second electric motor. Preferably, said second fork is clamped to said tubular shaft for translation along the approach axis. Preferably, said second fork is driven directly or indirectly by the second electric motor to move said tubular shaft along the approach axis. Preferably, said tubular shaft is rotatable around said approach axis with respect to said second fork. Preferably, in a first modality the drive shaft of the second electric motor is a rotary drive shaft. Preferably, in this case the second electric motor produces a mechanical moment in said transmission shaft directed selectively in a first angular direction and in a second angular direction. Preferably, in the first embodiment, said winder comprises a second control bar with a first end articulated with the second fork and a second end connected to the drive shaft of the second > S κ c An electric motor. Is it Preferably, a main extension shaft of the second control rod and the drive shaft of the second electric motor are arranged perpendicular to each other. Preferably, a speed reducer is interposed between the drive shaft of the second electric motor and the second control rod, configured to transmit a lower rotational speed to the second rod relative to the rotational speed of the drive shaft of the second electric motor. Preferably, this second control bar moves the tubular shaft along the approach axis. Preferably, in the first mode, said drive shaft of the second motor is driven to rotate in a first angular direction and translate the tubular shaft in a first direction along the approach axis. Preferably, in the first mode, the drive shaft of the second electric motor is driven to rotate in a second angular direction opposite to the first and to move the tubular shaft in a second direction along the approach axis. Preferably, in a second embodiment, the second electric motor is a linear electric motor and comprises a movable drive shaft. Preferably, the linear electric motor produces a force on said movable drive shaft selectively directed in a first direction and in a second direction. Preferably, said transferable drive axis is parallel to the approach axis of the tubular shaft. Preferably, in the second mode, the drive shaft of the second electric motor is driven to move the tubular shaft in a first direction along the approach axis. Preferably, in the second mode, the drive shaft of the second electric motor is driven to move the tubular shaft in a second direction along the approach axis. Preferably, this control unit is configured to generate a first control signal and send it to a driver of the first electric motor. Preferably, this control unit is configured to generate a second control signal and send it to a driver of the second electric motor. Preferably, this control unit is configured to generate a third control signal and send it to a driver of the third electric motor. Preferably, the first control signal and the second control signal are generated so that the translation of the drive bar and the translation of the tubular shaft are coordinated to achieve a predetermined grip movement. Preferably, the third control signal is generated to coordinate the translation of the drive bar and the translation of the tubular shaft with the rotation of the tubular shaft to achieve a predetermined movement and rotation of the gripper. Preferably, a user data entry interface is included that is configured to receive at least one data input representative of a desired grip operating parameter. > S 8 κ c N Preferably, the desired operating parameter of the gripper is chosen from at least one of the following: translation of the tubular axis along the approach axis in a first direction; translation of the tubular axis along the approach axis in a second direction; point, along the approach axis, at which a closing movement of the first and second jaws of the gripper begins; point, along the approach axis, at which a closing movement of the first and second jaws of the gripper ends; point, along the approach axis, at which an opening movement of the first and second jaws of the gripper begins; point, along the approach axis, at which an opening movement of the first and second jaws of the gripper ends;Advancement of the tubular shaft along the approach axis during which complete closure of the first and second jaws of the gripper occurs; advance of the tubular shaft along the approach axis during which complete opening of the first and second jaws of the gripper occurs; maximum opening rotation of the first and second jaws of the gripper; maximum closing rotation of the first and second jaws of the gripper; clamping torque of the first and second jaws of the gripper. Preferably, said control unit is configured to determine a grip motion law from said at least one desired operating parameter. Preferably, the law of motion of the grip is a mathematical function that describes the position of at least one representative point of the grip as a function of time. Alternatively or in combination, the grip motion law is preferably a mathematical function that describes the position of one or more representative points of the first and second jaws of the grip as a function of time. Preferably, said control unit is configured to interpolate at least one desired operating parameter with preset operating parameters to determine said grip motion law from the result of said interpolation. Preferably, these preset operating parameters are predetermined and set in the control unit by the manufacturer, e.g., stored in a memory of the control unit as system parameters. Preferably, these preset operating parameters are representative of positions that the gripper must necessarily reach over time in order to achieve the desired behavior. Preferably, at least one desired operating parameter can be represented by a plurality of points representing the desired grip position over time. Preferably, these pre-established operating parameters can be represented by a plurality of points representing the required grip position over time. Preferably, said law of motion is obtained by interpolating said plurality of points representing the required grip position in time and said plurality of points representing the desired grip position in time. Preferably, this control unit is also configured to determine, based on this law of > S 9 κ c N movement of the grip, a first law of movement of the drive bar and a second law of movement of the tubular shaft. Preferably, the first law of motion of the drive bar is a mathematical function that describes the position of at least one representative point on the drive bar as a function of time. More preferably, the first law of motion of the drive bar is a mathematical function that describes the position of at least one representative point of the drive bar along the drive axis as a function of time. Preferably, the second law of motion of the tubular shaft is a mathematical function that describes the position of at least one representative point on the tubular shaft as a function of time. More preferably, the second law of motion of the tubular shaft is a mathematical function that describes the position of at least one representative point of the tubular shaft along the approach axis as a function of time. Preferably, this first control signal is representative of the first law of motion of the tubular shaft. Preferably, said control unit is configured to generate said first control signal representative of the first law of motion and send it to said driver of the first electric motor. Preferably, this second control signal is representative of the second law of motion of the tubular shaft. Preferably, said control unit is configured to generate said second control signal representative of the second law of motion and send it to said drive of the second electric motor. Preferably, this third control signal is representative of the rotational speed of the tubular shaft. Preferably, this user data input interface is also configured to receive at least one more data input element representing the grip rotation speed. Preferably, the rotation speed of the grip matches the rotation speed of the tubular shaft. Preferably, an additional winder is provided. Preferably, the additional winder is used in combination with said winder to make a double-fold wrap, wherein a fold wrap is made at each of the opposite ends of the wrap. Preferably, the additional winder is identical in structure and operation to said winder. Preferably, the additional winder comprises an additional grip mechanically connected to one end of an additional tubular shaft. Preferably, said additional tubular shaft is rotatable about an additional approach axis and movable along said additional approach axis. Preferably, said additional grip is rotatable and fully movable with said additional tubular shaft. Preferably, said additional winder comprises an additional drive bar, active in said > S 10κ c N additional grip.É Preferably, the additional drive bar slides along an additional drive shaft parallel to, or coinciding with, said additional approach shaft. Preferably, said additional drive bar slides along said additional drive shaft with respect to said additional tubular shaft and is rotatably clamped to said additional tubular shaft. Preferably, this additional grip can be opened and closed after the additional drive bar is moved along the additional drive shaft. Preferably, the additional winder comprises a first additional electric motor active on said additional drive bar to move said additional drive bar along the additional drive shaft. Preferably, the additional winder comprises a second additional electric motor active on said additional tubular shaft to move said additional tubular shaft along the additional approach shaft. Preferably, this control unit is configured to drive the first additional electric motor and the second additional electric motor. Preferably, the additional approach axis is parallel to said approach axis. Preferably, the additional approach axis is also coaxial with said approach axis. Preferably, the additional drive shaft is parallel to said drive shaft. Preferably, the additional drive shaft is also coaxial with said drive shaft. BRIEF DESCRIPTION OF THE DRAWINGS Additional features and advantages of the present invention will be clarified from the following detailed description of a preferred embodiment thereof, with reference to the accompanying drawings provided by way of indicative and non-limiting example, in which: Figure 1 is a schematic perspective view of a wrapping device for product wrappers according to the present invention in an open condition. Figure 2 is a schematic perspective view of a detail of the wrapping device in Figure 1. Figure 3 is a schematic perspective view of some parts of the wrapping device detail from Figure 2. Figure 4 is a schematic perspective view of additional parts of the wrapping device detail from Figure 2. Figure 5 represents a schematic sectional view in the VV plane of a portion of the wrapping device of Figure 1. Figure 6 is a representative block diagram of some components of the wrapping device for product wrappers according to the present invention. > S κ c N DETAILED DESCRIPTION OF THE INVENTION In the accompanying figures, a wrapping device for product wrappers according to the present invention is generically referred to by numerical reference 1. Device 1 comprises a winder 10 shown on the left in Figure 1 and an additional winder 10a shown on the right in Figure 1. Located between the unwinder 10 and the additional unwinder 10a is a feeder for products to be wrapped 12 (represented schematically only) that rotates about a rotation axis X. The feeder for products to be wrapped comprises a plurality of bases (not illustrated), each of which accommodates a corresponding product to be wrapped, partially wrapped with a wrapping material. This wrapping material needs to be wound at one or both ends to form a fold or a pair of folds. The rotation of the feeder for products to be wrapped sequentially places the partially wrapped products between the unwinder 10 and the additional unwinder 10a. The unwinder 10 and the additional unwinder 10a are configured to make a corresponding fold in the product wrapper. The reel 10 and the additional reel 10a are arranged facing each other, with the product feeder 12 accommodated between them. The winder 10 and the additional winder 10a are structurally identical to each other, except as will be explicitly described later, and are arranged symmetrically with respect to an ideal plane perpendicular to the rotation axis X of the product feeder 12. Therefore, what is described in relation to winder 10 is identically valid for the additional winder 10a. The components of winder 10 are also present in the additional winder 10a and are represented in Figure 1, where necessary, with the corresponding reference numbers followed by the letter 'a'. The winder 10 comprises a grip 20 mounted on one end 21 of a tubular shaft 22. The tubular shaft 22 is mounted inside a containment body 23 from which the end 21 of the tubular shaft 22 emerges. The additional grip 20a, the additional tubular shaft 22a, and the end 21a of the additional tubular shaft 22a and the additional containment body 23a of the additional winder 10a are shown in Figure 1. As best shown in Figure 3, the tubular shaft 22 is rotatably mounted inside the containment body 23 (not shown in Figure 3) to rotate about an approach axis A. A drive rod 24 is inserted into the tubular shaft 22, which is rotatably integrated with the tubular shaft 22 via, for example, a bolt or form coupling. The drive bar 24 also rotates around the approach axis A. The tubular shaft 22 also slides along the approach axis between a rearward and a forward position. In the rearward position, the end 21 of the tubular shaft 22 is distanced from the feeder 11 of products to be wrapped, and in the forward position, the end 21 of the tubular shaft 22 approaches the feeder 11. S κ c N feeder 11 of products to be wrapped. AND The drive bar 24 slides along a drive axis B coincident with the approach axis A. The drive bar 24 slides into and with respect to the tubular axis 22. The drive bar 24 slides along the drive axis B between a rearward and forward position. When the drive bar 24 is in the forward position, one end 25 of the drive bar 24 protrudes further from the end 21 of the tubular axis 22 than when the drive bar 24 is in the rearward position. A first electric motor 30 is provided to drive the translation of the drive bar 24 along the drive axis B with respect to the tubular axis 22. A second electric motor 31 is provided to drive the translation of the tubular shaft 22 along the approach axis A. A third electric motor 32 is provided to drive the rotation of the tubular shaft 22 and the drive bar 24 with it. As shown in Figure 2, the third electric motor is connected to a drive shaft 40 that has a rotation axis C parallel and spaced from the approach axis A. In the preferred embodiment of the invention, a drive shaft of the third electric motor 32 is connected to a speed reducer 33. The speed reducer 33 is connected by an input shaft to the drive shaft of the third electric motor 32 and by an output shaft to the drive shaft 40. The function of the speed reducer 40 is to rotate the motor shaft 40 at a different (preferably lower) speed than the rotational speed of the motor shaft of the third electric motor 32. A pinion 41 is fitted to the motor shaft 40, which rotates integrally with the motor shaft 40. The pinion 41 is meshed with a toothed roller 42 having a rotation axis D parallel to the rotation axis of the drive shaft 40. The toothed roller 42 is also meshed with a gear 43 fitted to the tubular shaft 22. The rotation of the drive shaft 40 results in a rotation of the tubular shaft 22. Pinion 41, toothed roller 42, and gear 43 are all straight, so gear 43 can be translated along the approach axis A (together with the tubular shaft 22) without losing engagement with toothed roller 42. The dimension along the rotation axis D of toothed roller 42 is greater than the maximum translation length of the tubular shaft 22 along the approach axis A. The third electric motor 32 also drives the rotation of the additional tubular shaft 22a and the additional drive bar of the additional winder 10a. With regard to this, as shown in Figure 1, the drive shaft 40 extends between the winder 10 and the additional winder 10a until it reaches the additional winder 10a. In the additional winder 10a, the drive shaft comprises an additional pinion meshed with an additional toothed roller which is meshed with an additional pinion fitted to the additional tubular shaft 22a. > S κ c N As described above, a first electric motor 30 is provided to drive the drive bar 24 along the drive shaft B. With regard to this, the first electric motor 30 is active in a first fork 50 that is integrated next to the drive shaft to the drive bar 24. The drive bar 24 rotates about the drive shaft B with respect to the first fork 50. The first fork 50 comprises a passage opening through which the drive bar 24 slides. The first fork comprises a projection in sliding contact against two joints 61 integrated with the drive bar 24 and positioned on the opposite side with respect to the passage opening. When the first fork 50 is moved by the first electric motor 30 along the drive shaft B, the fork projection exerts a force against one of the two joints 61 integrated with the drive rod 24, causing the drive rod to move along the drive shaft B. Similarly, the second electric motor 31 is active in a second fork 51 that is integrated next to the approach shaft A to the tubular shaft 22. The tubular shaft 22 rotates about the approach shaft A with respect to the second fork 51. The second fork 51 comprises a passage opening through which the tubular shaft 22 slides. The second fork 51 comprises a projection in sliding contact against two joints 62 integrated with the drive shaft 22 and positioned on the opposite side with respect to the passage opening. When the second fork 51 is moved by the second electric motor 31 along the approach axis A, the projection of the second fork exerts a force against one of the two joints 62 integrated with the tubular shaft 22, causing the translation of the tubular shaft 22 along the approach axis A. During this translation, the pinion 43 moves relative to the toothed roller 42 without losing its engagement with it. In a first embodiment shown in the accompanying figures, the first electric motor 30 drives the first fork 50 by means of a first control rod 53. In this embodiment, the first electric motor 30 comprises a rotating drive shaft. The first electric motor 30 generates a mechanical torque on the rotating drive shaft, causing the latter to rotate. The first control bar 53 comprises a first end 54 articulated with the first fork 50 around a hinge axis perpendicular to the drive axis B. The first control bar 53 comprises a second end 55 opposite the first end 55, stably connected to the output shaft of a speed reducer 56. The speed reducer 56 comprises an input shaft connected to the drive shaft of the first electric motor 30. The function of the speed reducer 56 is to rotate the first control bar 53 at a different (preferably lower) speed to the rotational speed of the drive shaft of the first electric motor 30. When the first electric motor 30 is driven to rotate in a first angular direction, the first control rod 53 rotates accordingly in the same angular direction. The first control rod 53 initiates the movement of the first fork 50 in a first direction along the drive axis B. This first direction is directed towards the forward position of the drive rod 24. The first fork 50 pulls the rod of > S κ c N drive 24 to the forward position in translation. ? When the first electric motor 30 is driven to rotate in a second angular direction, the first control rod 53 rotates accordingly in the same angular direction. The first drive rod 53 initiates the movement of the first fork 50 in a second direction along the drive axis B. This second direction is directed towards the rearward position of the drive rod 24. The first fork 50 pulls the drive rod 24 to the rearward position in translation. In the first mode, the second electric motor 31 drives the second fork 51 by means of a second control rod 57. The second electric motor 31, similar to the first electric motor 30, comprises a rotary drive shaft. The second electric motor 31 generates a mechanical torque on the rotary drive shaft, causing the latter to rotate. The second control bar 57 comprises a first end 58 articulated with the second fork 51 around a hinge axis perpendicular to the approach axis A. The second control bar 57 comprises a second end 59 opposite the first end 58 permanently connected to the output shaft of a speed reducer 60. The speed reducer 60 comprises an input shaft connected to the drive shaft of the second electric motor 31. The function of the speed reducer 60 is to start the rotation of the second control bar 57 at a different (preferably lower) speed than the rotational speed of the drive shaft of the second electric motor 31. When the second electric motor 31 is driven to rotate in a first angular direction, the second control rod 57 rotates accordingly in the same angular direction. The second control rod 57 initiates the movement of the second fork 51 in a first direction along the approach axis A. This first direction is directed towards the forward position of the tubular shaft 22. The second fork 51 pulls the tubular shaft 22 to the forward translational position. When the second electric motor 31 is driven to rotate in a second angular direction, the second control rod 57 rotates accordingly in the same angular direction. The second control rod 57 initiates the movement of the second fork 51 in a second direction along the approach axis A. This second direction is directed towards the rearward position of the tubular shaft 22. The second fork 51 pulls the tubular shaft 22 to the rearward translational position. In a second, unillustrated embodiment, the first electric motor is a linear electric motor and comprises a movable drive shaft. The linear electric motor produces a force on the motor shaft that initiates the movement of the motor shaft along a straight path, either in a first direction or in a second direction opposite to the first. The translation direction of the drive axis is parallel and preferably coincident with the drive axis B. The drive shaft is connected to the first 50 fork, either directly or via a return. When the first electric motor 30 is driven to move the drive shaft in a first direction, the > S κ c The drive shaft initiates the movement of the first fork 50 in a first direction along the drive shaft B. This first direction is directed towards the forward position of the drive bar 24. The first fork 50 pulls the drive bar 24 to the forward position in translation. When the first electric motor 30 reaches the point where the drive shaft moves in a second direction, the drive shaft initiates the movement of the first fork 50 in a second direction along the drive shaft B. This second direction is directed towards the rearward position of the drive bar 24. The first fork 50 pulls the drive bar 24 to the rearward position in translation. In the second configuration, the second electric motor is a linear electric motor and comprises a movable drive shaft. The linear electric motor produces a force on the motor shaft that initiates the movement of the motor shaft along a straight path, either in a first direction or in a second direction opposite to the first. The translation direction of the impulse axis is parallel and preferably coincident with the approach axis A. The drive shaft is connected to the second fork 51, either directly or via a return. When the second electric motor 31 is driven to translate the drive shaft in a first direction, the drive shaft initiates the movement of the second fork 51 in a first direction along the approach axis A. This first direction is directed to the forward position of the tubular shaft 22. The second fork 51 drags the tubular shaft 22 to the forward translational position. When the second electric motor 31 moves the drive shaft in a second direction, the drive shaft initiates the movement of the second fork 51 in a second direction along the approach axis A. This second direction is directed towards the rearward position of the tubular shaft 22. The second fork 51 pulls the tubular shaft 22 to the rearward translational position. Grip 20 is integrated for translations along the approach axis A to the tubular axis 22 while the drive bar 24 is sliding along the drive axis B with respect to grip 20. The function of the tubular shaft 22 is to rotate and move the gripper 20 towards and away from the product to be wrapped. The purpose of the drive bar 34 is to open and close the gripper 20. The gripper 20 comprises (see Figure 5) a first jaw 70 and a second jaw 71. The first jaw 70 and the second jaw 71 are rotatably mounted about a respective fixing axis G in a gripper body 72. The gripper body 72 is clamped to the end 21 of the tubular shaft 22 and comprises a passage opening through which the drive rod 24 is slidably inserted. The first jaw 70 comprises a first toothed wheel 73 articulated on the respective fixing shaft G of the first jaw. The second jaw 71 comprises a second toothed wheel 74 articulated on the respective fixing axis G of the second jaw. The first gear 73 and the second gear 74 are permanently coupled in a > S κ c N rack 75 placed at one end of the drive bar 24. ? The translation of the drive bar 24 along the drive axis B causes a translation of the rack 75 and a consequent rotation of the first gear 73 and the second gear 74 in opposite angular directions. Rotation in opposite angular directions of the first gear 73 and the second gear 74 results in respective rotations of the first jaw 70 and the second jaw 71 of the gripper 20. A translation of the drive bar 24 to the forward position corresponds to rotations of the first jaw 70 and the second jaw 71 that close or tend to close the grip 20. A translation of the drive bar 24 to the rearward position corresponds to rotations of the first jaw 70 and the second jaw 71 that open or tend to open the grip 20. In order to coordinate the movements of the first electric motor 30 and the second electric motor 31, device 1 comprises a control unit 80 (with diagram in Figure 6). Control unit 80 is associated with user interface 81 (also diagrammed in Figure 6). User interface 81 is configured to receive at least one input data (ID, Input Datum) that represents a desired operating parameter (DOP, Desired Operating Parameter) from grip 20. The desired operating parameter (DOP) is a parameter that identifies the user's intended behavior of gripper 20 during its operation in a wrapper end-fold closing process. This desired behavior can be changed by the user by modifying the input data (ID) according to specific usage requirements. As an example, such a desired behavior parameter (DOP) could be the translation distance that the tubular shaft 20 must travel during a translation along the approach axis A to the forward position. In this case, the desired operating parameter (DOP) is related to the distance to which the gripper 20 is to be moved at the start of the operation to create the bend closure. An additional example of such a desired operating parameter (DOP) is the translation distance that the tubular shaft 20 must travel during a translation along the approach axis A to the rearward position. In this case, the desired operating parameter (DOP) is related to the distance that the gripper 20 will be moved at the end of the operation to create the bend closure. An additional example of such a desired operating parameter DOP may be the point, along the approach axis Ay during the translation of the tubular shaft to the forward position, at which a closing movement of the first jaw 70 and the second jaw 71 of the gripper 20 begins. Another example of such a desired operating parameter DOP may be the point, along the approach axis Ay during the movement of the tubular shaft to the rearward position, at which an opening movement of the first jaw 70 and the second jaw 71 of the gripper 20 begins. Additional examples of such a desired operating parameter DOP may be the point, along the approach axis A, at which an opening movement of the first jaw 70 and the second jaw 71 ends or at > S κ c N which completes a closing movement of the first jaw 70 and the second jaw 71. ¿É Additional examples of such a desired operating parameter DOP may be the distance traveled by the tubular shaft 22 along the approach axis A during which the complete closure of the first jaw 70 and the second jaw 71 occurs, or during which the complete opening of the first jaw 70 and the second jaw 71 of the gripper 20 occurs. Other examples of such a desired operating parameter (DOP) may be the maximum opening rotation of the first jaw 70 and the second jaw 71 or the maximum closing rotation of the first jaw 70 and the second jaw 71 of the gripper 20. Another example of such a desired operating parameter (DOP) may be the clamping torque of the first jaw 70 and the second jaw 71 of the gripper 20. In the preferred embodiment of the invention, the user interface 81 is configured to receive a plurality of representative input data IDs, each of a desired operating parameter DOP of the grip 20. The control unit 80 is configured at the hardware, software, and / or firmware level to obtain the desired operating parameters (DOP) from the input data (ID) and to determine a gripper motion law 20 from the derived desired operating parameters (DOP). The control unit comprises, for example, a processor 85 configured for this purpose. Such a law of movement of grip 20 expresses, e.g., in respective position / time diagrams and / or in respective mathematical functions, the position of grip 20 (or of a representative point of the position of grip 20) in time and the degree of opening and closing of the first jaw 70 and the second jaw 71 (or of representative points of the position of the first jaw 70 and the second jaw 71) in time. In a preferred mode, the control unit 80 is configured to determine the law of motion of gripper 20 by interpolating the desired operating parameters (DOP) with preset operating parameters (POP). These preset operating parameters (POP) are representative of the positions that grip 20 must necessarily reach over time to obtain the desired behavior. The desired operating parameters DOP can be expressed in terms of a plurality of points representing the desired position of gripper 20 in time and the desired position of the first jaw 70 and the second jaw 71 in time. In turn, the preset operating parameters POP can be expressed in terms of a plurality of points representing the required position of gripper 20 over time and the required position of the first jaw 70 and the second jaw 71 over time. By interpolating the above points (both those representing the desired position and those representing the required position), it is possible, for example, to determine the law of movement of grip 20. The control unit 80 is configured, once the gripper motion law 20 has been determined, to break down such motion law into a first drive bar motion law 24 and a second > S κ c N law of motion of the tubular shaft 22. ? The first law of motion of the drive bar 24 and the second law of motion of the tubular shaft are determined by the control unit 80 such that the simultaneous drive of the drive bar 24 according to the first law of motion and the tubular shaft 22 according to the second law of motion results in the drive of the gripper 20 according to its law of motion. The first law of motion expresses, e.g., in a position / time diagram and / or in a respective mathematical function, the position of the drive bar 24 (or of a representative point of the position of the drive bar 24) along the drive axis B in time. The second law of motion expresses, e.g., in a position / time diagram and / or in a respective mathematical function, the position of the tubular shaft 22 (or of a representative point of the position of the tubular shaft 22) along the approach axis A in time. Control unit 80 is configured to generate a first control signal CS1 that represents the first law of motion. In particular, the first control signal CS1 represents the position of drive bar 24 (or a representative point of the position of drive bar 24) along drive axis B in time. The first control signal CS1 is sent to an 82 drive of the first electric motor 30 to drive the first electric motor 30. Control unit 80 is also configured to generate a second control signal CS2 representing the second law of motion. In particular, the second control signal CS2 represents the position of the tubular shaft 22 (or a representative point of the position of the tubular shaft 22) along the approach axis A in time. The second control signal CS2 is sent to the driver 83 of the second electric motor 31 to drive the second electric motor 31. Control unit 80 is also configured to generate a third control signal CS3 and send it to a drive 84 of the third electric motor 32. The third control signal CS3 is generated to rotate the tubular shaft throughout the entire wrapping end bend winding process. The third control signal CS3 can be calculated with the control unit 80 from second input data ID2 entered into the user data entry interface 81. This second input data ID2 is representative of a desired rotation speed OP2 of gripper 20 and of the additional gripper 20a when present. The desired rotation speed DOP2 can be constant or variable over time. In the event of winding both ends of the wrapping in a fold to obtain a double fold, the control unit 80 is configured to generate a first additional control signal CS1a and a second additional control signal CS2a and send them to the respective drives 82a, 83a of the first additional electric motor 30a and the second > S κ c N additional electric motor 31 a of the additional winder 10a. AND Such first additional control signal CS1a and additional control signal CS2 are generated from at least one additional input data IDa entered into the user data input interface 81 and representative of an additional desired operating parameter DOpa of the additional grip 20a as described above. In this case, the additional desired operating parameter DOpa, in addition to the examples mentioned in connection with the desired operating parameter DOP, can also be the delay period between the start of the closing or opening of the first additional jaw and the second additional jaw with respect to the opening or closing of the first jaw and the second jaw. In some modes, the additional desired operating parameter DOpa and the desired operating parameter DOP can also be variable as a function of the desired set rotation speed DOP2.
Claims
1. A wrapping device (1) for product wrappers comprising: a winder (10) comprising: a gripper (20) mechanically connected to an end (21) of a tubular shaft (22), wherein said tubular shaft (22) is rotatable about an approach axis (A) and movable along said approach axis (A), and wherein said gripper (20) is rotatable and movable integrally with said tubular shaft (22); an actuating bar (24), active in said grip (20), which slides along a drive axis (B) parallel to, or coincident with, said approach axis (A), wherein said actuating bar (24) slides along said drive axis (B) with respect to said tubular axis (22) and is rotatably pressed to said tubular axis (22), and wherein said grip (20) can be opened and closed after a translation of said actuating bar (24) along said drive axis (B);a first electric motor (30) operating on said drive bar (24) to move said drive bar (24) along the drive axis (B); a second electric motor (31) operating on said tubular shaft (22) to move said tubular shaft (22) along the approach axis (A); said device further comprises a control unit (80) configured to drive the first electric motor (30) and the second electric motor (31).
2. The wrapping device (1) according to claim 1, comprises a third electric motor (32) active on said tubular shaft (22) to rotate said tubular shaft (22) around the approach axis (A); said control unit (80) being configured to drive the third electric motor (32).
3. The wrapping device (1) according to claim 2 comprises a drive shaft (40) connected to said third electric motor (32); a pinion (41) that is fitted to said drive shaft (40) to rotate with said drive shaft (40); a spur gear (43) that is fitted to said tubular shaft (22) and that is meshed directly or indirectly with said pinion (41).
4. The wrapping device (1) according to any of the preceding claims, wherein said winder (10) comprises a first fork (50) connected to a drive shaft of the first electric motor (30) and pressed to said drive bar (24) for translation along the drive shaft (B); said drive bar (24) being rotatable about said drive shaft (B) with respect to said fork (50).
5. The wrapping device (1) according to claim 4, wherein said winder (10) comprises a first control bar (53) having a first end (54) articulated with the first fork (50) and a second end (55) connected to a rotary drive shaft of the first electric motor (30); by moving said first control bar (53) the drive bar (24) along the drive shaft (B).
6. The wrapping device (1) according to claim 5, wherein said drive shaft > S 21k c N of the first electric motor (30) is driven to rotate in a first angular direction to translate the drive bar (24) in a first direction along the drive shaft (B), and to rotate in a second angular direction opposite to the first and translate the drive bar (24) in a second direction along the drive shaft (B).
7. The wrapping device (1) according to any of the preceding claims, wherein said winder (10) comprises a second fork (51) connected to a drive shaft of said second electric motor (32) and pressed to said tubular shaft (22) for translation along said approach axis (A); said tubular shaft (22) being rotatable about said approach axis (A) with respect to said second fork (51).
8. The wrapping device (1) according to claim 7, wherein said winder (10) comprises a second control bar (57) having a first end (58) articulated with the second fork (51) and a second end (59) connected to a rotary drive shaft of the second electric motor (31); moving said second control bar (57) the tubular shaft (22) along the approach axis (A).
9. The wrapping device (1) according to claim 8, wherein said drive shaft of the second electric motor (31) is driven to rotate in a first angular direction to translate the tubular shaft (22) in a first direction along the approach axis (A), and to rotate in a second angular direction opposite to the first and translate the tubular shaft (22) in a second direction along the approach axis (A).
10. The wrapping device (1) according to any of the preceding claims comprises a user data input interface (81) configured to receive at least one input data (ID) representative of a desired operating parameter (DOP) of the grip (20).
11. The wrapping device (1) according to claim 10, wherein said control unit (80) is configured to determine a gripper motion law (20) starting from said at least one desired operating parameter (DOP).
12. The wrapping device (1) according to claim 11, wherein said control unit (80) is configured to interpolate said at least one desired operating parameter (DOP) with preset operating parameters (POP) and determine said gripper motion law (20) from the result of said interpolation.
13. The wrapping device (1) according to claim 11 or 12, wherein said control unit (80) is further configured to determine, from said grip movement law (20), a first movement law of the drive bar (24) and a second movement law of the tubular shaft (22).
14. An enveloping device (1) according to claim 13, wherein said control unit (80) is configured to generate a first control signal (CS1) representative of the first law of motion and send it to an actuator (82) of the first electric motor (30) and generate a second control signal (CS2) representative of the second law of motion and send it to an actuator (83) of the second electric motor (31).
15. A wrapping device (1) according to any of the preceding claims, > S 22 κ c N further comprises an additional winder (1 Oa) comprising: An additional gripper (20a) mechanically connected to an end (21a) of an additional tubular shaft (22a), wherein said additional tubular shaft (22a) is rotatable about an additional approach axis and translatable along said additional approach axis and wherein said additional gripper (20a) is rotatable and translatable integrally with said additional tubular shaft (22a);an additional drive bar, active in said additional grip (20a), which slides along an additional drive axis parallel to, or coinciding with, said additional approach axis, wherein said additional drive bar is slidable along said additional drive axis with respect to said additional tubular axis (22a) and is rotatably pressed to said additional tubular axis (22a), and wherein said additional grip (20a) can be opened and closed after a translation of said additional drive bar along said additional drive axis; a first additional electric motor (30a) active in said additional drive bar for translating said additional drive bar along said additional drive axis;a second additional electric motor (31a) operating on said additional tubular shaft (22a) to move said additional tubular shaft (22a) along the additional approach shaft; said control unit (80) is configured to drive the first additional electric motor (30a) and the second additional electric motor (31a).;