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(11) | EP 0 670 266 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Apparatus for packaging compressed products |
| (57) Apparatus for packaging compressed products having two walls (31,32) between which
the products (4) are placed and in which holes connected to a source of compressed
air are formed. During the compression of the products (4), the compressed air forms,
between the products located at the ends and the walls (31,32), air cushions which
are adapted to reduce friction during the advancement of the products produced by
a pusher (66). |
[0001] The present invention relates to an apparatus for packaging compressed products such as diapers, sanitary napkins, rolls of absorbent paper for various uses, cellulose derivatives, and products having a soft compressible consistency.
[0002] The current method of packaging products of the above-mentioned type entails the formation of stacks whose volume is reduced to facilitate their insertion in a containment package. The stacks are accordingly compressed between two jaws and are pushed, in this condition, inside the package by a pusher. The high compression, however, produces high friction forces between the faces of the jaws that are in contact with the laterally located products, causing said products to deform and be damaged during the motion for transferring them into the package.
[0003] In order to obviate this drawback, it has already been proposed to place on the jaws belts that are capable of moving together with the products during their advancement.
[0004] However, the belt supporting structures are constructively complicated, as they have to withstand the considerable forces that occur during compression.
[0005] A principal aim of the present invention is to provide an apparatus which assuredly presses and transfers the products without damaging them in any way and at the same time entails structural solutions which are constructively simple and as such are economically advantageous.
[0006] This aim is achieved by an apparatus for packaging compressed products such as diapers, sanitary napkins, rolls of absorbent paper for various uses, cellulose derivatives, and products having a compressible soft consistency, characterized in that it comprises: a supporting surface for a plurality of products arranged so as to form a pack that can be compressed along an axis; a pair of opposite walls that rise at right angles from said supporting surface and lie at right angles to said compression axis; means for actuating said pair of walls between a spaced position, in which the pack of products is arranged between said walls in uncompressed condition, and a closer position, in which the pack of products is compressed and said walls form a channel for conveying the pack of compressed products; pusher means for making said pack of compressed products advance along said conveyance channel and for inserting it in a package located at the end of said conveyance channel; a plurality of holes being formed in said walls and being connected to a source of compressed air, said holes having openings which lead onto the opposite faces of said walls and are distributed so as to form, between said walls and the products located at the ends of the pack, an air cushion that runs from the region in which the pack of products is placed between the walls in uncompressed condition up to the region in which the pack of products lies inside the package at the end of the advancement stroke.
[0007] Further features and advantages of the invention will become apparent from the following detailed description of a preferred embodiment thereof, illustrated only by way of non-limitative example in the accompanying drawings, wherein:
figure 1 is a plan view of an apparatus for packaging flat products;
figure 2 is an elevation view taken along the transverse plane II-II of figure 1;
figure 3 is a lateral elevation view taken along the longitudinal plane III-III of figure 2;
figure 4 is an elevation view taken along the transverse plane IV-IV of figure 1.
[0008] With reference to the above figures, the apparatus comprises a footing 1 which supports, by means of shoulders 2a, 2b, 2c, and 2d, a horizontal surface 3 for supporting the products 4 to be packaged.
[0009] In the illustrated case, the products 4 to be packaged (diapers, sanitary napkins, and the like) are arranged edgeways and are aligned so as to form a pack or stack 5 whose axis is designated by the letter A.
[0010] Two threaded rods 6 and 7 are rotatably supported in the shoulders 2a, 2c and 2b, 2d and are mutually aligned along the direction B.
[0011] The rods 6 and 7 have opposite threads and respective end portions that are arranged in the space between the shoulders 2a and 2b. Toothed pulleys 8 and 9 are keyed on said end portions, and toothed belts 10 and 11 surround said pulleys and are closed in a loop around sprockets 12 and 13 which are in turn keyed on the opposite ends of an output shaft of a drive unit 14. The drive 14, which is provided with a flange below the footing 1, can be of any kind.
[0012] Two bushes 15 and 16 are engaged on the threaded rods 6 and 7 along the portions that lie between the shoulders 2a, 2c and 2b, 2d by means of a female thread or a similar ball-bearing system; a bracket 17 and 18 is rigidly coupled to each one of said bushes in an upward region. The bracket 17 is provided, in a downward region, with two sliding blocks 19 and 20 that slide in respective guides 21 and 22 which are fixed to the footing 1 and are parallel to the rods 6 and 7.
[0013] The bracket 18 also has identical guiding means which are not shown in the drawings but are fully evident.
[0014] Two respective angular sliders, generally designated by the reference numerals 25 and 26, are fixed to the brackets 17 and 18 by means of spacer strips 23 and 24. The strips 23 and 24 cross the surface 3 at slots 27 and 28 that run in the direction B, that is to say, parallel to the guides 19 and 20, to allow the brackets 17 and 18 to slide, as will become apparent hereinafter.
[0015] Each angular element 25 and 26 comprises a base 29 and 30 which is fixed to the strips 23 and 24 and a vertical wall 31 and 32 which is fixed at right angles to the front edge of the base 29 and 30 and is reinforced at the rear by lateral ribs 33 and 34. The walls 31 and 32 form a channel 35 for conveying the stack 5 in the direction C, at right angles to direction B, and have a plurality of holes 36 which are distributed along a plurality of horizontal rows (two in the illustrated example) and lead into the channel 35 with their openings.
[0016] Bars 37 (see the enlarged-scale detail of figure 2) are applied to the rear of the walls 31 and 32 at the holes of each row; channels 38 are formed in said bars and are adapted to connect the holes of each row. The channels 38 are in turn connected to a source of compressed air by means of flexible ducts which are connected to the bars 37.
[0017] Downstream of the angular sliders 25 and 26, a device, generally designated by the reference numeral 39, is provided which is meant to open the mouth of the packages that must receive the stacks 5 of products.
[0018] Said device comprises a shaft which is rotatably supported in the shoulders 2a-2d and has two threaded portions 41 and 42 with opposite threads that run between the shoulders 2a, 2c and 2b, 2d respectively.
[0019] Female-thread bushes 43 and 44 are coupled to the portions 41 and 42, and respective platforms 45 and 46 are fixed above said bushes. Each platform rigidly supports a vertical plate 47 and 48 which is surmounted by an arm 49 and 50 which runs towards the centerline plane D of the apparatus.
[0020] In practice, the platforms 45 and 46, the vertical plates 47 and 48, and the arms 49 and 50 form two sliders 51 and 52 which can be moved mutually closer or further apart by screwing in one direction or the other the shaft 40 with opposite threads by means of the handwheel 53.
[0021] In order to prevent the sliders from rotating about the shaft 40, there is a rod (not shown in the drawing) which is parallel to the shaft 40, is fixed to the shoulders 2a-2d, and is slidingly guided in seats of the female threads 43, 44 which are parallel to the seats for the portions 41 and 42.
[0022] Respective vertical pivots 54 and 55 are fixed between the inner ends of the platforms 45 and 46 and of the arms 49 and 50; two bodies 58 and 59 for the coupling of a pair of vertical plates 60 and 61 are rotatably mounted on said pivots by means of bearings 56 and 57.
[0023] The bodies 58 and 59 have wings 62 and 63 to which the stems of hydraulic jacks 64 and 65 are articulated; the cylinders of said jacks are pivoted to the plates 47 and 48.
[0024] The jacks 64 and 65 are actuated between a position in which the plates 60 and 61 are arranged substantially transversely to the channel 35 and a parallel position in which the plates 60 and 61 are co-planar with respect to the walls 31 and 32. The co-planar condition is referred to the position of the walls 31 and 32 at the end of their mutual approach stroke.
[0025] The described apparatus is completed by a pusher 66 which is adapted to push the stack 5 in the direction C.
[0027] In an initial condition the sliders 25 and 26 are spaced, as shown in figure 1 by the dashed lines.
[0028] Likewise, the sliders 51 and 52 are also spaced by such an extent that when the plates 60 and 61 are moved into the parallel position they are co-planar with respect to the walls 31 and 32.
[0029] A stack of uncompressed products, aligned along the axis A, is then placed between the walls 31 and 32.
[0030] At this point the motor 14 is activated so as to cause the mutual approach of the sliders 25 and 26 and accordingly compress the products 4 of the stack. Simultaneously, compressed air starts to be supplied to the holes 36, so that air cushions form between the walls 31 and 32 and the products 4 that are adjacent to them, keeping the products substantially spaced from said walls.
[0031] By actuating the pusher 66, the stack 5 of compressed products is made to advance along the channel 35 with no appreciable friction between the products and the walls.
[0032] While the products advance in the direction C along the surface 3, the plates 60 and 61 are rotated, by means of the actuation of the jacks 64 and 65, from their transverse position into the position in which they are parallel to the walls 31 and 32, at which they are inserted in the mouth of a package 67 which is meant to receive the products, so as to facilitate the insertion of the products in the package.
[0033] Once this step has ended, the pusher 66 is returned to the initial position, the walls 31 and 32 are spaced again, and the cycle can resume in the above described manner in order to insert a new stack of products.
[0034] It is evident that the apparatus according to the invention achieves the intended aim. Advantageously, in a first different embodiment of the invention the walls 31 and 32 are moved towards each other so that they are closer than the plates 60 and 61, so that by taking advantage of the delay with which the stack tends to expand when it passes between the plates 60 and 61 it is possible to push it into the package with minimal friction.
[0035] In another embodiment, for the same purpose of reducing the sliding friction of the products on the plates 60 and 61, said plates are provided with rows of holes 68 which lead onto the conveyance channel 35 and are connected to a source of compressed air by means of channels 69 formed in the plates (see enlarged-scale detail view of figure 4).
[0036] In a further advantageous embodiment, in order to reduce air consumption the channels 38 are divided in a linear fashion into several independent portions which are controlled sequentially to allow the supply of air only through the holes in front of which the stack is located during its advancement.
[0037] The movement of the compression walls 31 and 32 can be provided by means of hydraulic jacks that act directly or with the interposition of suitable lever systems instead of being provided by means of a screw-and-nut mechanism as shown in the figures.
[0038] Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.
1. Apparatus for packaging compressed products (4) such as diapers, sanitary napkins,
rolls of absorbent paper for various uses, cellulose derivatives, and products having
a compressible soft consistency, characterized in that it comprises: a supporting
surface (3) for a plurality of products (4) arranged so as to form a pack (5) that
can be compressed along an axis (A); a pair of opposite walls (31, 32) that rise at
right angles from said supporting surface (3) and lie at right angles to said compression
axis (A); means (6, 7) for actuating said pair of walls (31, 32) between a spaced
position, in which the pack (5) of products (4) is arranged between said walls in
uncompressed condition, and a closer position, in which the pack (5) of products (4)
is compressed and said walls (31, 32) form a channel (35) for conveying the pack (5)
of compressed products (4); pusher means (66) for making said pack (5) of compressed
products (4) advance along said conveyance channel (35) and for inserting it in a
package located at the end of said conveyance channel; a plurality of holes (36) being
formed in said walls (31, 32) and being connected to a source of compressed air, said
holes (36) having openings which lead onto the opposite faces of said walls (31, 32)
and are distributed so as to form, between said walls (31, 32) and the products (4)
located at the ends of the pack (5), an air cushion that runs from the region in which
the pack (5) of products (4) is placed between the walls (31, 32) in uncompressed
condition up to the region in which the pack (5) of products (4) lies inside the package
at the end of the advancement stroke.
2. Apparatus according to claim 1, characterized in that said opposite walls (31, 32)
are mounted on sliders (25, 26) which are slideable along guides (21, 22) and are
provided with female threads which are coupled to respective threaded rods (6, 7)
that have opposite threads, pulleys (8, 9) being keyed on said rods (6, 7) and being
connected to an actuation motor (14) by means of a transmission that uses belts (10,
11).
3. Apparatus according to claim 1 or 2, characterized in that said holes (36) branch
from channels (38) which are connected to a source of compressed air.
4. Apparatus according to claim 3, characterized in that said channels (38) are divided
in a linear fashion into multiple independent portions, each one of which is connected
to the source of compressed air, said portions being controlled sequentially so as
to allow to deliver air only through the holes (36) in front of which the pack (5)
is located during its advancement along the conveyance channel (35).
5. Apparatus according to one of claims 1 to 4, characterized in that downstream of said
compression walls (31, 32) there is a device (39) for opening the mouth of a package
meant to receive the pack (5) of products (4), said device (39) comprising: a shaft
(40) which is rotatably supported and has two portions (41, 42) which have opposite
threads; two female threads (43, 44) which are coupled to said portions (41, 42) and
to which a respective slider (51, 52) is associated; a plate (60, 61) which is articulated
to each slider (51, 52) about a vertical axis (54, 55); and means (64, 65) to actuate
said plates (60, 61) between a position in which they are arranged substantially transversely
to the conveyance channel (35) and a position in which they are co-planar with respect
to said compression walls (31, 32).
6. Apparatus according to claim 5, characterized in that said actuation means are constituted
by hydraulic jacks (64, 65) which act between said plates (60, 61) and the supporting
sliders (51, 52).
7. Apparatus according to claim 5 or 6, characterized in that said plates (60, 61) are
provided with holes (68) which are connected, through channels (69), to a source of
compressed air and lead into said conveyance channel (35).
8. Apparatus for packaging compressed products such as diapers, sanitary napkins, rolls
of absorbent paper for various uses, cellulose derivatives, and products having a
soft compressible consistency, according to what can be deduced from the description
and from the drawings.