Patent Application
20130333338
The present disclosure is related to packaging folded products within film. More particularly, the present disclosure relates to packaging folded tissue products within a film overwrap. Even more particularly, the present disclosure relates to an improved apparatus for the packaging of compressible articles, especially stacks of facial tissues and paper handkerchiefs into a blank formed from a plastic film or the like.
In the packaging of pulp products, especially stacks of facial tissues and paper handkerchiefs, a considerable problem arises because the articles to be packaged are compressed to a considerable extent. It is therefore difficult to produce an exact cuboid pack.
To this end the drum machines for wrapping packs of facial tissues and paper napkins generally use an apparatus called a “revolver.” The revolver is essentially a drum that rotates about a horizontal axis. The revolver is typically provided with a plurality of radially disposed chambers, often called “revolver pockets.” These revolver pockets generally provide the forming geometry for the articles to be packaged. Within the revolver pockets, the packs of facial tissues and paper handkerchiefs to be wrapped are individually inserted in rapid succession. Each pack to be wrapped is fed by a driving chain and compressed prior to the introduction into a corresponding revolver pocket.
The insertion takes place with the simultaneous interposition of a film of suitable plastic material provided for wrapping the facial tissues and/or paper handkerchiefs (i.e., to make up the envelope) after having been properly folded around the sides of the pack and closed by welding and/or gluing. Owing to the high rotary speed of the revolver, it is usually necessary to feed and compress the facial tissues and/or paper handkerchiefs at a rate sufficiently high to allow for successively engaging all the revolver pockets to ensure a convenient productive capacity of the plant. This implies a synchronization with minimum tolerance margins of the steps for feeding, squeezing and, then, inserting the facial tissues and/or paper handkerchiefs into the revolver pockets, mainly as a function of the revolver peripheral speed and of the variation of the momentum to be imparted to each pack prior to the insertion thereof into the revolver pockets.
Thus, the adoption of suitable criteria in the management of the plant, in relation to both the choice of the most suitable operating speeds and the maintenance and adjustment of the individual devices, is required to allow provide complete operative integration and maximum reliability. It is well known, the level and rate of activities for the maintenance and adjustment of the components weigh heavily on the economic efficiency of the plant and, accordingly, on the cost of fabrication of the finished packaged product. Thus, there is a strong demand to use simpler and more robust equipment and processes to improve the reliability of the production systems and reduce the relevant costs related to the manufacture of the packaged product.
Some prior art equipment requires a stoppage for each group of napkins before operating the squeezing and the subsequent insertion thereof into the revolver pockets, and for bringing the compressive means back to the respective initial operating condition before starting the wrapping of a new group of napkins. That is, bringing the compressive means back behind the next group of napkins to be wrapped, so that the feeding thereof to the revolver results discontinuous. Moreover, the functional construction of known apparatus does not allow an increase in the output of the plant, that is, in the napkins-feeding rate, beyond a given value corresponding to the operating speed of the compressive means. In addition to this, there is the fact that the constructional complexity of this known apparatus brings about an intense servicing activity which weighs on the production cost of the packaged product. Such equipment is described in U.S. Pat. No. 4,845,924.
Another packaging machine can utilize a pair of belt conveyers converging towards an articles-compressing device which is made up of a pair of parallel horizontal superimposed belts for moving the napkins delivered from the feeding belts, and also made of a vertical operating cylinder, in a fixed position, provided with a flat head and a corresponding stationary abutment surface, to compress the thus fed napkins. However, this known apparatus also provides for a discontinuous feeding of napkins, owing to the stoppage of the belts of the compressive device, which is necessary to allow for the intervention of the compressive cylinder. Accordingly, the output capacity of the plant cannot be raised beyond a value corresponding to the operating speed of the cylinder. Such equipment is described in German Patent DE 2322878.
Other machines or processes related to high speed packaging can use a drum provided with radial pockets with dimensions that are suitable for the product to be packaged, inside which the stacks of product to be packaged are inserted in rapid succession, with the simultaneous interposition of one blank plastic film, so as to obtain the complete wrapping of each stack, completed by welding applied on the film to obtain a closed packaging. This arrangement of equipment of this type is described in U.S. Pat. Nos. 4,845,924 and 5,459,979.
In machines of this kind, due to the high operation speed that is required to ensure suitable productivity, it is very complex to compress the stack, keep its correct geometry and carry out the insertion inside the pockets of the drum without causing deformations or faults in the wrapping by the film. In particular, but not exclusively, it is difficult, if not impossible, to keep control of the position of the film and of the compression in the radial direction of insertion during the wrapping step when the speed increases beyond a certain limit, causing defects in the package which, in any case, can occur also when the speed is kept below said limit. Thus, it would be beneficial to provide an apparatus for packaging stacks of facial tissues and/or paper handkerchiefs that provides better throughput, increased reliability, and a packaged product with a better finished appearance to increase consumer appeal.
The present disclosure provides for an apparatus for packaging stacks of folded tissue products or the like with blanks of plastic film. The apparatus comprises at least one pocket comprising a plurality of side walls disposed within a drum having a longitudinal axis, a plurality of adjacent grooves disposed upon the side walls within the pocket, insertion means for inserting a single stack in the pocket, along an insertion direction, with the interposition and consequent folding of a corresponding blank, and control means adapted to drive the stop means along the insertion direction in a coordinated manner with respect to the operation of the insertion means. The pocket has a leading edge coexistant with the surface of the drum. Each of the grooves has a longitudinal axis generally parallel to the longitudinal axis of the drum. The plurality of grooves extends from the leading edge to a position internal to the pocket. The pocket is operatively associated with stop means of the stack completely inserted within the pocket. The stop means comprise suction means adapted to keep hold of the film, and to hold off the same film at least in an extraction step wherein the stack is extracted from the pocket.
The present disclosure also provides a pocket for a drum suitable for use in packaging stacks of folded tissue products or the like with blanks of plastic film. The pocket comprises a plurality of side walls disposable within the drum having and a plurality of adjacent grooves disposed upon the side walls within the pocket. The pocket has a leading edge coexistant with the surface of the drum. Each of the grooves has a longitudinal axis generally parallel to a longitudinal axis of the drum. The plurality of grooves extends from the leading edge to a position internal to the pocket.
The present disclosure also provides a leading edge for a pocket for a drum suitable for use in packaging stacks of folded tissue products or the like with blanks of plastic film. The leading edge comprises a plurality of adjacent grooves disposed upon the side walls within the pocket. Each of the grooves has a longitudinal axis generally parallel to a longitudinal axis of the drum. The plurality of grooves extends from the leading edge to a position internal to the pocket.
A device 4 feeds the stacks 3 into a compression device or system 8. This typically occurs along a plane 35 that is generally inclined with respect to the horizon by about 10°. As shown with particularity in
A multiple cam upper actuation device 12 drives a first crank and rod upper device 13 for controlling the insertion device 5 of the stacks 3. In other words the device 12 displaces the device 5 along the arm 6. The upper actuation device 12 also has a second crank and rod upper device 14 for radially controlling a mobile cam portion 22 for inserting the plastic packaging film. The actuation device 12 also provides for a third crank and rod upper device 15 for controlling the radial displacement of the device 8 for compressing the stacks 3.
A multiple cam lower actuation device 16 drives a first crank and rod lower device 17 for controlling the lower compression plate 9 of the stacks 3. The lower actuation device 16 also provides a second crank and rod lower device 18 for controlling the front stop plate 10 of the stacks 3. The lower actuation device 16 also has a third crank and rod lower device 19 for controlling the rotation of the lower oscillating arm 7. Further the lower actuation device 16 provides a fourth crank and rod lower device 20 for controlling the rotation of the upper oscillating arm 6.
Both cam actuation devices provide a mechanism that provides an eccentrically rotating disc that peripherally defines a cam surface with where a crank comes into tangential contact. The crank is hinged at one end and contacts the cam surface at a crank intermediate point so that the same crank is driven in oscillation around a hinge point in response to the rotation of the disc. The rods linking the cranks to the various controlled devices are in turn pivotably connected to the same devices and to the cranks in predetermined points between the crank intermediate point of contact with the disc and a free end of the crank. The geometric characteristics are suitably set as a function of the mutually coordinated displacements.
Cam portion 22 drives extractors 24 that are preferably designed to assist in the insertion of the packaging film with in the individual pockets 58. Cam portion 22 provides a radially displaceable end portion (as seen driven by the second upper device 14) of a fixed cam 23 that revolves according to a curl around the axis of the drum on a side thereof. In practice, the fixed cam 23 does not traverse about a closed ring, but rather an open loop. The opening of the loop is defined by a circumferential and radial discontinuity (e.g., “step-like” discontinuity) in the film insertion area. Cam portion 22 is preferably provided in cooperative engagement with the discontinuity and is displaceable radially between a radially external position (i.e., the guide cam larger diameter) and a radially internal position (i.e., guide cam smaller diameter). The displacement accordingly drives the movement of the extractors.
In an area 23a opposite the discontinuity of the fixed cam 23, the fixed cam 23 then moves in a continuous manner from the smaller to the larger diameter to drive the extractors 24 between a rearward displaced position and a radially extracted position for pushing the packaged stacks 3 out of the pockets 58. The outlet of the packages from the drum 21 is shown as reference numeral 25 in
A band of film 29 fed by a cylinder 30 in a continuous manner for packaging the product is cut in pre-defined length blanks 38 by a cutting cylinder 31 having a blade 32. A transverse welding system 39 the welds the film once it has been wrapped around the stacks 3.
As shown in
Returning to
As shown in
A second sequential valve 26 (crown valve) is fixably connected to shaft 42 integral to drum 21 and is activated at about 2/3 of the insertion step, as a result of the movement of the extractors 24. When the tail end of the extractors 24 abuts the bottom of grooves defined by the crown valve 26, the suction exerted by the extractors themselves is turned off. Before the insertion is complete, the film is disposed outwardly effectively providing adhesion of the film to the stack 3 due to the suction applied to the end flaps of the blank of film 38 by the passages 40 disposed on the surface of the drum 21.
A valve 26 disposed proximate to the bottom of the relative grooves can be provided with different diameters to control the insertion depth where one desires to turn off the applied suction. A depression chamber 28 transmits the suction to the extractors 24 and can be fed by a vacuum source with values. This was found to provide a safe positioning of the film during the insertion step.
The machine described can be arranged for vertical or horizontal feeding. It is believed that to provide best operation, the insertion plane 35 (described supra) have a certain inclination relative to the horizontal, preferably descending towards the drum 21 and preferably equal to about 10°. In such a way the stacks 3, as shall be comprised more clearly hereafter, adhere to the front stop plate in perfectly perpendicular arrangement with respect to the plane defined by the lower compression plate 9.
Referring to
When the stacks 3 are removed from the cylinder 85, the belts 50 and internal belts 86 transport the stacks to their insertion point within the compression device 8. The outlet rollers 52 of the belts 50, 86 are preferably adjusted to provide an equidistant position with respect to the middle plane 54 as a function of the height of the product to be packaged. The speed of the belts 50, 86 can vary according to the diameter of the cylinder 85 and to the number of cavities 84 present within the cylinder 85. The compressed height of the stacks 3 upon exiting the belts 50, 86 is about the same as that of the finally packaged product. The stacks 3 are then inserted into the compression device 8 in its condition of maximum opening 56 at the bottom dead centre of the arm 7. Preferably, the height 56 is normally 50% greater with respect to the height of the stacks 3 dispensed from the outlet of the belts 50, 86. When the stack 3 is inserted into the compression device the stack 3 expands and becomes adherent with the stop plate 10 which exerts a suction assisting with alignment with the stop plate 10.
It should be noted that the control of the stacks 3 within drum 21, with the film wound in the pockets, is also provided by the extractors 24 which, due to the movement of the cam portion 22 in the area of insertion of the stack 3 into the pocket, moves rearwards providing an inner side abutment accompanying the same stacks 3 in their insertion displacement.
Further, the suction exerted by the extractors 24 contributes to keep the stack and the wrapping film in an orderly fashion. When the packet passes in correspondence with the welding system, it is welded and then expelled thanks to the ejection of its extractor driven by the evolution 23a of the cam 23 in the area diametrically opposed to that of insertion. The control of the suction/depression exerted by the extractors 24 is synchronized along the appropriate rotation angle of the drum, by means of the valves 26 and 27.
The stack stop plate 10, fixedly connected to the basement, with its depression system, for providing alignment of the stack 3, is in turn capable of ensuring a significant improvement of the insertion operations, for speed, precision and constructive optimization. The extractor 24 accompanies the insertion of the stack 3 into the pocket 58 with precise control of the position of the film through fluid connection to the vacuum source.
The pocket 58 is preferably provided with leading edges 60 that provide a grooved geometry to the entry point of the pocket 58. An exemplary leading edge 60 is provided in
Independent of the geometry of the grooves 62, it is believed that the grooves 62 should be provided in order to increase the surface area of the leading edge 60. Without desiring to be bound by theory, it is believed that by increasing the surface area of leading edge 60, the corresponding frictional forces exerted upon the film being inserted (or pulled) into pocket 58 (along with the stack 3) results in a more even insertion of the film into pocket 58. A more even insertion of film into pocket 58 can result in a more repeatable and equitable distribution of film about stack 3. Clearly, one of skill in the art will recognize the clear benefit of a more robust packaging having significantly better consumer appeal.
Grooves 62 are preferably provided upon the portion of leading edge 60 that extends within the pocket 58. Additionally, grooves 62 can be provided upon the portion of leading edge 60 that is disposed upon the surface of drum 21 disposed proximate to pocket 58.
In most current commercial embodiments, drum 21 is typically provided with a 12-pole design for the production of packages of stacks of folded tissue products. Such a 12-pole design has 12 pockets symmetrically and evenly spaced about the circumference of drum 21. A typical drum 21 diameter is 600 mm to allow the film cut-off length arranged on the surface of drum 21. Independent from the diameter of drum 21 (which could be vary as a function of cut-off length and pack size) for a specific execution of a 12-pole drum 21 having a diameter of 600 mm to produce packages of stacks of folded tissue products having dimensions of about 52 mm×23 mm×110 mm it was found that grooves 62 covered about 25% of the surface of both side walls of pocket 58. It is preferred that grooves 62 starting at the leading edge 60. Preferably, grooves 62 are provided with an overall depth of about 0.2 mm. The corresponding pitch between adjacent groves spaced radially from the longitudinal axis of drum 21 is preferably about 0.6 mm. Further, it is preferred that the top width of groove 62 be about 0.4 mm and have a groove distance at root of 0.2 mm. Additionally, it is preferred that grooves 62 be provided within pocket 58 to provide a total coverage area of from about 15% to about 30%.
It is believed that such a leading edge 60 can provide symmetrical film in-feed into the pocket 58 while under pressure (e.g., vacuum feed) and provide better registration of the stack 3 to the film to provide the finally formed product. Without desiring to be bound by theory, it is believed that providing cross-machine direction grooves 62 at the leading edge of the pocket 58 provides a source of equal friction on both sides of the pocket 58 during in-feed of the stack 3 into the pocket 58.
After arms 6 and 7 have reached a mutual alignment position that is suitable for allowing the insertion of the stack in a pocket 58 of the drum 21 , the insertion device 5, moves radially toward the drum 21 until it abuts against the stack 3 of compressed product. Once a position in which the distance from the periphery of the drum 21 corresponds to the width of the stack 3 has been reached, the mobile cam portion 22 moves radially rearward with the stack 3 of product to provide secure placement within pocket 58 of drum 21 for complete insertion.
Stack 3 and arms 6 and 7 rotate in phase with one another and with one of the pockets 58 of the drum 21. The device 5 proceeds forwards until the stack 3 is completely inserted within pocket 58. Vacuum provided by the extractor is applied to the film that has been disposed upon the surface of drum 21. The film is disposed to be positioned upon the surface of drum 21 so that equal portions of film are disposed on either machine direction side of pocket 58. Passages 40 connected to a source of negative pressure (e.g., vacuum) is applied to a blank of film that has been previously interposed for the wrapping operation. Positioning of the film can be provided upon the surface of drum with any means known to those of skill in the art.
After insertion of a stack 3, lower arm 7 and the compression plate 9 return to the starting position to receive a new stack 3 of products. The upper arm 6 arrives at the top dead centre and inverts its movement, whereas the insertion device begins its radial movement along the arm 6 so as to return to the starting position, without interfering, as already mentioned, with the upper compression plate 64 which, being part of the device 8, is already in position to receive a new stack 3. The drum 21 continues its rotation with constant speed and a new packaging pocket 58 proceeds to the point in phase with the arms 6, 7. The system is ready for a new cycle.
Returning to follow the path of the stacks inside the drum 21, it should be noted that the control of the stacks, with the film wound in the pockets, is also taken up by the extractors 24 which, due to the movement of the cam portion 22 in the area of insertion, move rearwards thus providing an inner side abutment accompanying the same stacks in their insertion displacement
The suction exerted by the extractors 24 contributes to keep the stack 3 and the wrapping film in an orderly fashion. When the packet passes in correspondence with the welding system, it is welded and then expelled thanks to the ejection of its extractor driven by the evolution 23a of the cam 23 in the area diametrically opposed to that of insertion. The control of the suction/depression exerted by the extractors 24 is synchronized along the appropriate rotation angle of the drum, by means of the valves 26 and 27.
The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Instead, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as “40 mm” is intended to mean “about 40 mm.”
Every document cited herein, including any cross referenced or related patent or application, is hereby incorporated herein by reference in its entirety unless expressly excluded or otherwise limited. The citation of any document is not an admission that it is prior art with respect to any invention disclosed or claimed herein or that it alone, or in any combination with any other reference or references, teaches, suggests or discloses any such invention. Further, to the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to that term in this document shall govern.
While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.
