Patent Description:
A packer machine generally folds blanks around products to be packed or folds blanks in order to obtain empty packs designed to subsequently house, on the inside, products to be packed. As a consequence, a packer machine generally comprises a blank feeding unit, which houses a stack of blanks in a hopper and allows single blanks to be retrieved, one after the other, from a bottom of the stack (arranged in the area of a pick-up opening of the hopper) in order to direct the single blanks towards the folding line.

In the area of the pick-up opening, the hopper has holding elements, which fulfil the function of providing support for the blanks arranged inside the hopper, so as to prevent the blanks from getting out in an uncontrolled manner. In order to extract a blank from the pick-up opening of the hopper, (at least) a sucking holding head engages the blank and pulls the blank with a movement that allows the edges of the blank to slip out of the holding elements; during the retrieving operations, the blank generally slightly deforms so as to facilitate the extraction of the edges thereof from the holding elements.

Modern packer machines are more and more often subjected to a format change, namely to a series of technical interventions aimed at adjusting the production of the packs to a different format (size); in other words, in order to shift from the production of packs with a given size (format) to the production of packs with a different size (format), operators have to act upon different parts of the packer machine in order to adapt them to the new size (format). In order to change the size (format) of the packs, it obviously is necessary to use blanks with a different size (format) and, hence, the hopper of the feeding unit needs to be adjusted so as to contain and dispense blanks having a different size (format). The format change operations undergone by a blank hopper are particularly timeconsuming and complicated, as the precise adjustment of the position of the holding elements arranged in the area of the pick-up opening requires numerous attempts; indeed, the position of the holding elements must be the result of a complicated compromise between the need to properly hold the stack of blanks inside the hopper (hence, avoiding that, while removing a blank, one or more adjacent blanks are accidentally removed as well) and the need not to damage (dent or scratch) the edges of the blank while retrieving it. Namely, the holding elements must sufficiently project into the pick-up opening in order to properly hold the stack of banks inside the hopper, but they cannot project too much into the pick-up opening so as not to damage the edges of the blank during the retrieving operations.

Patent <CIT> discloses the preamble of claim <NUM> and describes an infeed station for conveying and positioning a stack of carton blanks for sequential removal by a carton feeder; the infeed station includes a hopper and a magazine that receives carton blanks from the hopper. The magazine comprises a sensing mechanism including a control sensor and a warning sensor mounted in proximity to the carton blanks in the infeed station, and a processor that, according to a condition signalled by the sensing mechanism, controls the rate at which advancing belts advance a queue of carton blanks toward the magazine.

The object of the invention is to provide a blank feeding unit for a packer machine, said feeding unit allowing a format change to be carried out in a very quick manner, ensuring at the same time an ideal holding of the blanks (namely, ensuring that the edges of the blanks are not damaged in any way during the retrieving operations).

According to the invention, there is provided a blank feeding unit for a packer machine according to the appended claims.

The appended claims describe embodiments of the invention and form an integral part of the description.

The invention will now be described with reference to the accompanying drawings, showing a non-limiting embodiment thereof, wherein:.

In <FIG>, number <NUM> indicates, as a whole, a blank used to manufacture a pack designed to contain a group of coffee capsules.

The blank <NUM> comprises two (pre-weakened) longitudinal folding lines <NUM> and a plurality of (pre-weakened) transverse folding lines <NUM>, which define, between the two longitudinal folding lines <NUM>, a panel <NUM> making up an upper wall of the pack, a panel <NUM> making up a rear wall of the pack, a panel <NUM> making up a lower wall of the pack and a panel <NUM> making up a front wall of the pack. On the opposite sides of the panel <NUM> there are two panels <NUM>, which make up side walls of the pack and are connected to the panel <NUM> by the two longitudinal folding lines <NUM>. The panels <NUM> and <NUM> have a coffee capsule extraction opening, which is normally closed by a hinged lid <NUM>.

The blank <NUM> comprises two wings <NUM>, which are connected to a longitudinal folding line <NUM>, and two wings <NUM>, which are connected to the other longitudinal folding line <NUM> on the opposite side relative the wings <NUM>; in particular, two wings <NUM> and <NUM> are arranged at opposite ends of the panel <NUM> and are connected to the panel <NUM> by the two longitudinal folding lines <NUM>, whereas the other two wings <NUM> and <NUM> are arranged at opposite ends of the panel <NUM> and are connected to the panel <NUM> by the two longitudinal folding lines <NUM>. The wings <NUM> delimit, between one another, an empty space with a triangular shape, which has a vertex <NUM> in the area of a longitudinal folding line <NUM>.

According to <FIG>, there are blanks <NUM> (all having the same conformation, namely the same arrangement of panels and wings) with different formats (namely, different sizes), so as to manufacture corresponding packs having smaller or larger dimensions (namely, aimed at containing a different number of capsules and/or capsules with a different size). All blanks <NUM> with a different format (different size) can overlap one another using the corresponding vertexes <NUM> as position reference, namely always keeping the corresponding vertexes <NUM> in the same position (as shown in <FIG>). In other words, all blanks <NUM> with a different format (different size) can overlap one another aligning the corresponding vertexes <NUM> with one another, so that the vertexes <NUM> are in the same position (as shown in <FIG>).

In <FIG>, number <NUM> indicates, as a whole, a blank feeding unit <NUM> to feed blanks <NUM> in a packer machine designed to pack coffee capsules. In particular, the packer machine comprises the feeding unit <NUM>, which retrieves single blanks <NUM> from a stack of blanks <NUM>, a packing unit, which receives the single blanks <NUM> from the feeding unit <NUM> and folds the blanks <NUM> so as to form empty and open packs (namely, having the upper wall lifted relative to the rest of the pack), a filling unit, where robotic arms insert single coffee capsules into the open packs, and a closing unit, where the filled packs are closed (namely, the upper wall is caused to rest against and be glued to the rest of the pack).

According to <FIG>, the feeding unit <NUM> comprises a frame <NUM>, which rests on the ground by means of feet, and a hopper <NUM>, which is carried by the frame <NUM>, is designed to contain a stack of blanks <NUM> and has a pick-up opening <NUM> (visible for example in <FIG>), through which one blank <NUM> at a time can be retrieved from the stack of blanks <NUM>. Furthermore, the feeding unit <NUM> comprises a conveyor <NUM>, which is supported by the frame <NUM> and moves the blanks <NUM> along a straight and horizontal moving path P, which ends in the hopper <NUM>; the moving path P could also be inclined relative to the horizontal so as to have a (small or great) inclination oriented towards the hopper <NUM> so that gravity tends to move the blanks <NUM> towards the hopper <NUM>. Finally, the feeding unit <NUM> comprises a pick-up device (not shown), which is arranged in the area of the pick-up opening <NUM> of the hopper <NUM> so as to engage, in use, the pick-up opening <NUM> in order to retrieve single blanks <NUM> from the stack one after the other and feed the blanks <NUM> towards the packing unit.

The pick-up device (not shown) comprises a rotary drum rotating around a central axis of its and at least one sucking holding head, which is supported by the drum so as to cyclically move along a closed path and through a holding station, where the holding head engages the pick-up opening <NUM> of the hopper <NUM> in order to retrieve a blank <NUM>, and through a following release station, where the holding head feeds the blank <NUM> to the packing unit. Since (as better described below) the dimensions of the pick-up opening <NUM> are smaller than the dimensions of a blank <NUM> (so as to hold, in the absence of the pick-up device, the blanks <NUM> inside the hopper <NUM>), a blank <NUM> needs to elastically deform in order to be extracted from the pick-up opening <NUM> of the hopper <NUM>.

The hopper <NUM> comprises a flat containing wall <NUM> with a rectangular shape (arranged approximately perpendicularly to the moving path P), which has, at the centre, a through hole <NUM> (better visible in <FIG>, <FIG> and <FIG>) having dimensions that are larger than the dimensions of the blanks <NUM>, so that the blanks <NUM> can go through the hole <NUM> with a given (relatively large) clearance. According to <FIG>, the hopper <NUM> comprises a plurality of support brackets <NUM>, which are designed to support (on all sides) the stack of blanks <NUM>, are arranged around the hole <NUM> and are mounted on the containing wall <NUM>; in other words, the support brackets <NUM> define a channel that goes through the hole <NUM> and houses the stack of blanks <NUM> with a minimum clearance. Furthermore, the hopper <NUM> comprises a plurality of holding teeth <NUM> and <NUM>, which project into the pick-up opening <NUM> so as to prevent the blanks <NUM> from getting out and are mounted on the containing wall <NUM>; in other words, the holding teeth <NUM> and <NUM> extend into the pick-up opening <NUM> so as to reduce the passage section of the pick-up opening <NUM> and hold the blanks <NUM> of the stack inside the hopper <NUM>. Hence, the holding teeth <NUM> and <NUM> allow the pick-up opening <NUM> to gain dimensions that are smaller than the dimensions of a blank <NUM> so as to hold, in the absence of the action of the pick-up device, the blanks <NUM> inside the hopper <NUM>. According to a preferred embodiment, the holding teeth <NUM> and <NUM> are mounted on the support brackets <NUM>, which, in turn, are mounted on the containing wall <NUM>; namely, each support bracket <NUM> directly fixed to the containing wall <NUM> supports, in turn, corresponding holding teeth <NUM> and <NUM>.

The hopper <NUM> comprises a reference element <NUM>, which, in use is arranged in contact with the stack of blanks <NUM> and establishes a position reference for the blanks <NUM> of the stack of blanks <NUM>; in particular, the reference element <NUM> establishes the position of the vertex <NUM> of each blank <NUM>. Namely, the position reference established by the reference element <NUM> is configured to be in contact with the same point of each blank <NUM> regardless of the format of the blank <NUM>. In particular, the reference element <NUM> has, in cross section, a triangular shape and has an upper vertex, which establishes the position reference and is indirect contact with the stack of blanks <NUM>; namely, the vertex of the triangular shape of the cross section of the reference element <NUM> is in direct contact with the vertex <NUM> of each blank <NUM> so as to establish the position of the vertex <NUM> of each blank <NUM>. According to a preferred embodiment, the reference element <NUM> is mounted on the containing wall <NUM> and, hence, is integral to the hopper <NUM>.

As mentioned above, there are blanks <NUM> (all having the same conformation, namely the same arrangement of panels and wings) with different formats (namely, different sizes), so as to manufacture corresponding packs having smaller or larger dimensions; as a consequence, the feeding unit <NUM> needs to be adjusted so as to be able to contain blanks <NUM> with a different format by means of a format change operation (which obviously involves the entire packer machine). In other words, when the packer machine has to produce packs with a different format (difference size), it is necessary to stop the packer machine, empty the packer machine from the blanks <NUM> of the old format, adjust the entire packer machine (hence, also the feeding unit <NUM> of the packer machine) to the new format and, finally, insert the blanks <NUM> of the new format. As a consequence, in order to contain blanks <NUM> with different formats, the feeding unit <NUM> can be adjusted by means of a format change operation, which entails changing the feeding unit <NUM> from a first (old) configuration, which is suited to contain a first (old) format of the blanks <NUM>, to a second (new) configuration, which is suited to contain a second (new) format of the blanks <NUM>, which is different from the first (old) format.

The reference element <NUM> of the hopper <NUM> is arranged, in use, in contact with the stack of blanks <NUM>, establishes a position reference for the blanks <NUM> of the stack of blanks <NUM> (establishing the position of the vertex <NUM> of each blank <NUM>), is - relative to the frame <NUM> - in the same position regardless of the format of the blanks <NUM> and, hence, is not moved - relative to the frame <NUM> - due to a format change operation. In other words, at the end of all format change operations, the reference element <NUM> of the hopper <NUM> always is in the same position relative to the frame <NUM>, so that, regardless of the format (size) of the blanks <NUM>, the vertex <NUM> of each blank <NUM> always is in the same position relative to the frame <NUM>.

According to <FIG>, <FIG> and <FIG>, the feeding unit <NUM> comprises a reference element <NUM>, which has, in cross section, the same shape as the reference element <NUM>, is aligned with the reference element <NUM> so as to build an extension of the reference element <NUM>, is separate from and independent of the hopper <NUM> and the reference element <NUM>, is arranged along the moving path P in the area of the conveyor <NUM> and is mounted on the frame <NUM> in the same position regardless of the format of the blanks <NUM> (exactly like the reference element <NUM>) and, hence, is not moved, relative to the frame <NUM>, due to a format change operation. In other words, during a format change operation, all the other adjustable elements of the feeding unit <NUM> are moved relative to the frame <NUM>, but the two reference elements <NUM> and <NUM>, on the other hand, always remain in the same position relative to the frame <NUM> (obviously, net of unavoidable constructive tolerances). The reference element <NUM> is an extension (without gaps) of the reference element <NUM> inside the hopper <NUM>, whereas, from another point of view, the reference element <NUM> is an extension (without gaps) of the reference element <NUM> inside the conveyor <NUM>.

According to a different embodiment which is not shown herein, the reference elements <NUM> and <NUM> could coincide, if the reference element <NUM> were long enough to also incorporate the function of the reference element <NUM> or vice versa; in other words, the two reference elements <NUM> and <NUM>, instead of being separate and independent, could build one single indivisible body.

As schematically shown in <FIG>, the feeding unit <NUM> comprises a plurality of hoppers <NUM>, which are different from one another and interchangeable, each of them being associated with a corresponding format (size) of the blanks <NUM>; in other words, an equipment (a kit) for the feeding unit <NUM> is provided, which comprises a plurality of different and interchangeable hoppers <NUM>, each associated with a corresponding format of the blanks <NUM>. As a consequence, each hopper <NUM> is designed and adjusted so as to only treat one single corresponding format of the blanks <NUM>; hence, during a format change operation, the old hopper <NUM>, which is suited for the old format (size) of the blanks <NUM> has to be removed and, then, the new hopper <NUM>, which is suited for the new format (size) of the blanks <NUM>, has to be installed.

In order to allow for a quick replacement of the hopper <NUM> during a format change operation, the hopper <NUM> is fixed to the frame <NUM> in a quickly removable manner (since the format change operation entails replacing an old hopper <NUM> associated with the old format with a new hopper <NUM> associated with the new format).

According to a preferred embodiment shown in <FIG> and <FIG>, the frame <NUM> comprises a support body <NUM>, which is provided with a seat designed to house the hopper <NUM>. In particular, the seat of the support body <NUM> reproduces in negative the (rectangular) shape of the containing wall <NUM> of the hopper <NUM> so as to house, on the inside, the containing wall <NUM>; as a consequence, the support body <NUM> is shaped like a rectangular frame, within which the containing wall <NUM> of the hopper <NUM> is placed.

The support body <NUM> is movable on the frame <NUM> so as to move, during a format change operation, between a work position (shown in <FIG> and <FIG>), in which the hopper <NUM> housed in the support body <NUM> is coupled to and aligned with the conveyor <NUM>, and a replacement position (shown in <FIG>), in which the hopper <NUM> housed in the support body <NUM> is uncoupled from and not aligned with the conveyor <NUM>. In the replacement position (shown in <FIG>), the hopper <NUM> housed in the support body <NUM> is relatively far from the conveyor <NUM> and from the other components of the feeding unit <NUM> and, hence, is in an obstacle-free space, which largely facilitates both the operations to be carried out in order to remove the old hopper <NUM> from the support body <NUM> and the operations to be carried out in order to install the new hopper <NUM> in the support body <NUM>. In particular, the frame <NUM> comprises two carriages <NUM> carrying the support body <NUM> and two corresponding sliding guides <NUM> (oriented horizontally and perpendicularly to the moving path P), a corresponding carriage <NUM> sliding along each one of them so as to move the support body <NUM> between the work position (shown in <FIG> and <FIG>) and the replacement position (shown in <FIG>).

According to a preferred embodiment, the feeding unit <NUM> comprises a locking device <NUM>, which can be electrically operated in a remote manner and can be activated in order to constrain the support body <NUM> (carrying the hopper <NUM>) to the frame <NUM> when the support body <NUM> is in the work position (shown in <FIG> and <FIG>); namely, the locking device <NUM> can be activated so as to prevent the support body <NUM> (carrying the hopper <NUM>) from moving when the feeding unit <NUM> is operating. By way of example, the locking device <NUM> could have a pneumatic actuation and could comprise a mushroom-shaped pin, which is fixed to an edge of the support body <NUM>, and a servo-assisted clamp mechanism, which is designed to clamp the pin so as to constrain the pin and, hence, the support body <NUM> to the frame <NUM>.

Preferably, the support body <NUM> has two upper seats <NUM> and two lower seats <NUM> (partially visible in <FIG>); furthermore, each hopper <NUM> comprises two pins <NUM> (better shown in <FIG>), which project from opposite ends of the containing wall <NUM> and are configured to be inserted into the corresponding lower seats <NUM>, and comprises two hooking mechanisms <NUM> (better shown in <FIG> and manually operated by means of respective levers), which project from opposite ends of the containing wall <NUM>, are configured to be inserted into the corresponding upper seats <NUM> and can be operated (in a manual manner, by rotating the respective levers) so as to constrain the containing wall <NUM> to the support body <NUM>. A hopper <NUM> is coupled to the support body <NUM> by inserting, at first, only the two pins <NUM> into the corresponding lower seats <NUM> of the support body <NUM>, then by causing the hopper <NUM> to rotate around the pins <NUM> until the hooking mechanisms <NUM> are inserted into the corresponding upper seats <NUM> and, finally, by (manually) operating the hooking mechanisms <NUM> so as to constrain the hopper to the support body <NUM>.

Preferably, the support body <NUM> has a handle <NUM>, which can be grabbed by a user in order to push or pull the support body <NUM> when the support body <NUM> needs to be (manually) moved between the work position (shown in <FIG> and <FIG>) and the replacement position (shown in <FIG>). Similarly, each hopper <NUM> has a series of handles <NUM>, which are fixed to the containing wall <NUM> of the hopper <NUM> and can be grabbed by a user in order to manually handle the hopper <NUM>. In order to make the hopper <NUM> lighter and, hence, make the manual handling of the hopper <NUM> easier, the containing wall <NUM> has a series of lightening through holes; furthermore, the containing wall <NUM> is generally made of a light and resistant material, such as for example an aluminium alloy or a composite material (for example a carbon fibre-based material).

According to <FIG>, the conveyor <NUM> comprises three motor-driven conveyor belts <NUM>, which are parallel and next to one another along the moving path P, are mounted on the frame <NUM> and are arranged under the blanks <NUM> so as to support the blanks <NUM>. Each conveyor belt <NUM> comprises a belt closed in a ring shape around two end pulleys; an end pulley is an idle pulley, whereas the other end pulley is motor-driven and receives the motion from a corresponding electric motor. Preferably, the conveyor belts <NUM> have independent electric motors, namely each conveyor belt <NUM> is moved by an independent electric motor of its own; in this way, the moving speed of the three conveyor belts <NUM> can be adjusted in a differentiated manner.

According to a preferred embodiment, each conveyor belt <NUM> is mounted on the frame <NUM> in a movable manner so as to move, during a format change operation, along at least two adjustment directions D1 and D2, which are perpendicular to one another and perpendicular to the moving path P; in particular, the adjustment direction D1 is horizontal, whereas the other adjustment direction D2 is vertical.

According to a preferred embodiment, for each conveyor belt <NUM>, the conveyor <NUM> comprises (at least) a carriage, which (indirectly) supports the conveyor belt <NUM>, and a sliding guide (typically consisting of two rods parallel to one another), which is oriented parallel to the adjustment direction D1 and along which the carriage slides in order to move the conveyor belt <NUM> along the adjustment direction D1; in particular, there is an electric motor (namely, an electrically controlled actuator), which controls the movement of the carriage along the sliding guide and, for example, is mechanically coupled to the carriage by means of a screw-nut screw coupling (the screw is caused to rotate by the electric motor, thus determining the axial translation of the nut screw, which engages the screw and is integral to the carriage). A further screw-nut screw coupling is mounted on the carriage: the screw oriented along the vertical adjustment direction D2 is caused to rotate by a further electric motor, thus determining the axial translation of the nut screw, which engages the screw and supports the conveyor belt <NUM>.

According to a preferred embodiment, the entire conveyor <NUM> (namely, the three conveyor belts <NUM> with all corresponding mechanisms for the translation along the two adjustment directions D1 and D2) is mounted on the frame <NUM> in a movable manner so as to move, during a format change operation, between a work position (shown in <FIG>), in which the conveyor <NUM> is coupled to the hopper <NUM>, and a replacement position (shown in <FIG>), in which the conveyor <NUM> is uncoupled and at a given distance from the hopper <NUM>; in particular, the movement of the conveyor <NUM> between the work position (shown in <FIG>) and the replacement position (shown in <FIG>) takes place through a horizontal translation parallel to the moving path P (hence, perpendicular to the adjustment directions D1 and D2). The main purpose of the movement of the conveyor <NUM>, which only takes place during a format change, is that of moving the conveyor <NUM> away from the hopper <NUM> so as to remove all possible couplings between the conveyor <NUM> and the hopper <NUM> and, hence, subsequently allow the support body <NUM> (carrying the hopper <NUM>) to slide. A further purpose of the movement of the conveyor <NUM>, which only takes place during a format change, is that of moving the conveyor <NUM> away from the hopper <NUM> so as to create a larger free space around the hopper <NUM> and, hence, facilitate the replacement of the hopper <NUM>.

According to a preferred embodiment shown in <FIG>, the feeding unit <NUM> comprises two carriages <NUM>, which support the entire conveyor <NUM> (namely, the three conveyor belts <NUM> with all corresponding mechanisms for the translation along the two adjustment directions D1 and D2), and two sliding guides <NUM>, which are oriented parallel to the moving path P and along which the carriages <NUM> slide in order to move the entire conveyor <NUM> between the work position (shown in <FIG>) and the replacement position (shown in <FIG>); in particular, there is an electric motor (namely, an electrically controlled actuator), which controls the movement of the carriages <NUM> along the sliding guide <NUM> and, for example, is mechanically coupled to the carriages <NUM> through a screw-nut screw coupling (the screw is caused to rotate by the electric motor, thus determining the axial translation of the nut screw, which engages the screw and is integral to one of the carriages <NUM>).

According to <FIG>, the hopper <NUM> comprises (at least) a support bracket <NUM>, which projects towards a corresponding conveyor belt <NUM> of the conveyor <NUM>, provides support for the stack of blanks <NUM> along an end segment of the moving path P and has a "U"-shape, which defines, at the centre, a seat <NUM>, into which an end part of the conveyor belt <NUM> is inserted. The movement of the conveyor <NUM>, which only takes place during a format change, allows the corresponding conveyor belt <NUM> to be moved away from the seat <NUM> so as to subsequently allow the support body <NUM> (carrying the hopper <NUM>) to slide.

According to <FIG> and <FIG>, the hopper <NUM> supports a plurality of fixed holding teeth <NUM>, which project into the pick-up opening <NUM> in order to prevent the blanks <NUM> from getting out; the fixed holding teeth <NUM> are mounted in a fixed position, namely are mounted so as not to make any type of movement.

Furthermore, according to <FIG> and <FIG>, the hopper <NUM> also supports three movable holding teeth <NUM>, which project into the pick-up opening <NUM> in order to prevent the blanks <NUM> from getting out through the pick-up opening <NUM>; unlike the fixed holding teeth <NUM> (which do not make any type of movement and always remain in the same position), each movable holding tooth <NUM> is mounted so as to move between an extracted position (shown in the accompanying figures), in which it projects into the pick-up opening <NUM> to a greater extent, and a retracted position (not shown), in which it projects into the pick-up opening <NUM> to a smaller extent.

In particular, for each movable holding tooth <NUM> there is an elastic element <NUM>, which pushes the holding tooth towards the extracted position (shown in the accompanying figures), and each movable holding tooth <NUM> is associated with a position sensor <NUM>, which is configured to detect the position of the movable holding tooth <NUM>. The feeding unit <NUM> comprises a control unit <NUM> (schematically shown in <FIG>), which is configured to adjust the moving speed of the conveyor <NUM> (namely, of the conveyor belts <NUM> of the conveyor <NUM>) depending on the reading received from the position sensor <NUM>. In particular, the control unit <NUM> is configured to adjust the moving speed of the conveyor belts <NUM> so that the movable holding teeth <NUM> move with a synchronized motion (namely, move with a predetermined and desired time sequence) during the pick-up of a blank <NUM>. For example, if, during the pick-up of a blank <NUM>, a movable holding tooth <NUM> on the right moves with too much advance/delay relative to the other holding teeth <NUM>, then the right conveyor belt <NUM> is slowed down/accelerated.

The format change operations to be carried out to change the feeding unit <NUM> from an old configuration suited to contain an old format (size) of the blanks <NUM> to a new configuration suited to contain a new format (size) of the blanks <NUM> are described below.

At first, the packer machine is stopped and then the feeding unit <NUM> is stopped as well; when the feeding unit <NUM> has stopped, the old blanks <NUM> are removed from the feeding unit <NUM> and, when the feeding unit <NUM> is empty (namely, without blanks <NUM>), the conveyor <NUM> is moved (through the action of a corresponding electric motor) from the work position (shown in <FIG>) to the replacement position (shown in <FIG>).

Only when the conveyor <NUM> is in the replacement position (shown in <FIG>), the locking device <NUM> can be operated so as to release (free) the support body <NUM> (carrying the old hopper <NUM>) from the frame <NUM>. At this point, an operator manually causes the support body <NUM> to slide from the work position (shown in <FIG> and <FIG>) to the replacement position (shown in <FIG>); when the support body <NUM> is in the replacement position (shown in <FIG>), an operator can remove the old hopper <NUM> associated with the old format (size) of the blanks <NUM> from the support body <NUM> and, then, can install the new hopper <NUM> associated with the new format (size) of the blanks <NUM> on the support body <NUM>.

Usually at this point (but this could also take place before or after), the control unit <NUM> changes the position of the conveyor belts <NUM> of the conveyor <NUM> along the adjustment directions D1 and D2 (using the corresponding electric motors) so as to adjust the position of the conveyor belts <NUM> to the new format (size) of the blanks <NUM>.

At the end of the replacement of the hopper <NUM> and of the adjustment of the conveyor belts <NUM> of the conveyor <NUM>, an operator can manually cause the support body <NUM> to slide form the replacement position (shown in <FIG>) to the work position (shown in <FIG> and <FIG>); when the support body <NUM> is in the work position (shown in <FIG> and <FIG>), the locking device <NUM> is operated so as to constrain (lock) the support body <NUM> (carrying the new hopper <NUM>) to the frame <NUM>. Only when the support body <NUM> is constrained to the frame <NUM> in the work position (shown in <FIG> and <FIG>), the conveyor <NUM> can be moved (through the action of a corresponding electric motor) from the replacement position (shown in <FIG>) to the work position (shown in <FIG>).

Finally, the blanks <NUM> of the new format are loaded into the feeding unit <NUM>, thus completing the format change operations.

As mentioned above, during all format change operations, both reference elements <NUM> and <NUM> remain in the same position relative to the frame <NUM>, namely they do not change the position of the position reference established by them relative to the frame <NUM> (obviously, net of inevitable constructive tolerances). In particular, the reference element <NUM> is replaced (as it is mounted on the hopper <NUM>), but, switching from the old hopper <NUM> to the new hopper <NUM>, the position of the reference element <NUM> relative to the frame <NUM> does not change (i.e. the reference element <NUM> of the new hopper <NUM> is exactly in the same position as the reference element <NUM> of the old hopper <NUM>). The reference element <NUM> could be replaced or not be replaced (in order to adjust its shape to the different conformation of the blanks <NUM>), but, even in case of replacement of the reference element <NUM>, the position of the reference element <NUM> does not change during the replacement (i.e. the new reference element <NUM> is exactly in the same position as the old reference element <NUM>).

In the preferred embodiment shown in the accompanying figures, the conveyor <NUM> is active, namely it has motor-driven elements (the conveyor belts <NUM>) that push the blanks <NUM> along the moving path P; according to a different embodiment, the conveyor <NUM> is passive, namely it has no motor-driven elements, and exclusively uses gravity to push the blanks <NUM> along the moving path P (which must obviously be inclined relative to the horizontal).

In the preferred embodiment shown in the accompanying figures, the packer machine manufactures packs for coffee capsules. According to other embodiments which are not shown herein, the packer machine manufactures packs for food products, for smoking products, for personal hygiene articles or other products.

The embodiments described herein can be combined with one another.

The feeding unit <NUM> described above has numerous advantages.

First of all, the feeding unit <NUM> described above significantly reduces the reconfiguration times needed to adjust to a new format (size) of the blanks <NUM>; namely, the feeding unit <NUM> described above minimizes the time needed to carry out a format change, which entails changing the feeding unit <NUM> from an old configuration suited to contain an old format (size) of the blanks <NUM> to a new configuration suited to contain a new format (size) of the blanks <NUM>.

This result is obtained thanks to the fact that there are a plurality of different and interchangeable hoppers <NUM>, each associated with a corresponding format (size) of the blanks <NUM>; therefore, during format change operations, the whole hopper <NUM> is entirely replaced and the new hopper <NUM> installed already is perfectly set and adjusted for the corresponding format (size) of the blanks <NUM>, with no need for any additional adjustment. Furthermore, this result is also obtained thanks to the fact that the hopper <NUM> has a reference element <NUM>, which, in use, is placed in contact with the stack of blanks <NUM>, establishes a position reference for the blanks <NUM>, is, relative to the frame <NUM>, in the same position regardless of the format (size) of the blanks <NUM> and, hence, is not moved, relative to the frame <NUM>, due to a format change operation. The presence of the reference element <NUM> ensures that, each time the hopper <NUM> is replaced, the new hopper <NUM> finds the blanks <NUM> in a position known beforehand and, therefore, all the adjustment previously made to the hopper <NUM> still are completely valid and do not need to be changed (updated).

As a consequence, format change operation only require the replacement of the hopper <NUM> (which can be carried out in a few minutes thanks to the particular conformation of the hopper <NUM>), but not other adjustment has to be made to the holding teeth <NUM> and <NUM> (which are the holding elements arranged in the area of the pick-up opening <NUM>), as each hopper <NUM> (and, hence, the holding teeth <NUM> and <NUM> thereof) is associated with (and, hence, already adjusted to) one single corresponding format (size) of the blanks <NUM>.

Furthermore, the feeding unit <NUM> described above is simple and economic to be manufactured, since it does not require complicated mechanical pieces.

Claim 1:
A unit (<NUM>) to feed blanks (<NUM>) in a packer machine and comprising:
a frame (<NUM>);
a hopper (<NUM>), which is supported by the frame (<NUM>), is designed to hold a stack of blanks (<NUM>) and has a pick-up opening (<NUM>), through which one blank (<NUM>) at a time can be picked up from the stack of blanks (<NUM>); and
a conveyor (<NUM>), which is supported by the frame (<NUM>) and moves the blanks (<NUM>) along a moving path (P), which ends in the hopper (<NUM>);
wherein, in order to contain blanks (<NUM>) with different formats, the feeding unit (<NUM>) can be adjusted by means of a format change operation, which entails changing the feeding unit (<NUM>) from a first configuration, which is suited to contain a first format of the blanks (<NUM>), to a second configuration, which is suited to contain a second format of the blanks (<NUM>), which is different from the first format;
wherein the hopper (<NUM>) comprises a first reference element (<NUM>), which, in use, is placed in contact with the stack of blanks (<NUM>), establishes a position reference for the blanks (<NUM>) of the stack of blanks (<NUM>), is, relative to the frame (<NUM>), in the same position regardless of the format of the blanks (<NUM>) and, hence, is not moved, relative to the frame (<NUM>), due to a format change operation,
the feeding unit (<NUM>) is characterized in that:
the hopper (<NUM>) is configured to contain blanks (<NUM>) each comprising: two longitudinal folding lines (<NUM>), a plurality of transverse folding lines (<NUM>) defining, between the two longitudinal folding lines (<NUM>), a plurality of panels (<NUM>-<NUM>), two first wings (<NUM>), which are connected to a first longitudinal folding line (<NUM>) and delimit, between one another, an empty space with a triangular shape and having a vertex (<NUM>) in the area of the first longitudinal folding line (<NUM>), and two second wings (<NUM>), which are connected to a second longitudinal folding line (<NUM>); and
the first reference element (<NUM>) is placed and shaped in such a way that the position reference is located in the area of the vertex of the empty space (<NUM>) defined between the two first wings (<NUM>) of each blank (<NUM>).