[0001] The present invention relates to a high-precision strip feeding device, in particular
for packaging-box assembling machines.
[0002] Automatic devices for sequentially feeding stacked strips to a conveyor element which
enters a machine for assembling packaging boxes, such as for example boxes for fruit
or other products, are known.
[0003] Said devices generally comprise a loading element which contains the stacked strips
and is arranged above the conveyor element to be fed. The stacked strips are arranged
transversely to the direction of advancement of the conveyor element, and proximate
to the lower end of the loading element there is an extraction element which acts
in a cyclic manner on the strip which is arranged below all the others, so as to disengage
it from the loading element and pass it onto the conveyor element.
[0004] The strip is usually extracted from the loading element by moving said strip transversely
with respect to the direction of advancement of the conveyor element, so as to make
it engage, with one of its ends, traction means which are appropriately provided on
the conveyor element. The other end of the strip is thus disengaged from a support
of the loading element, which keeps the strips in a raised position with respect to
the traction means, and falls onto the conveyor element so that it, too, is correctly
engaged by the traction means.
[0005] European Patent Application N. 90119016.5, filed October 4, 1990 by the same Applicant
discloses a feeding device with an extraction element which, besides disengaging the
lower strip from the overlying stack of strips, places it on the conveyor element,
eliminating the unpredictability of the fall which is present in conventional devices
and thus allowing to significantly increase the strip feeding rate and therefore to
increase the productivity of the entire box assembly line.
[0006] Since the passage of the strip from the loader to the conveyor element occurs with
a transverse motion of the strip with respect to the conveyor element and with the
sequential deposition of one end and then of the opposite end of the strip on said
conveyor element, the distance between two successive traction means arranged on the
conveyor element must be greater, by a certain extent, than the dimensions of the
strip in the direction which is parallel to the direction of advancement of the conveyor
element. Otherwise, the strip could not be correctly engaged by the traction elements.
[0007] Although the device described in the above mentioned patent, by virtue of the elimination
of the gravity descent of the strips onto the feeding element, allows to significantly
contain the difference between the distance between two successive traction means
and the dimensions of the related strip, in many cases the strips must be fed closely
spaced from one another to the assembly machine, i.e., the traction means must be
arranged on the conveyor element at length intervals which are substantially equal
to the dimensions of a strip parallel to the advancement direction. Said length intervals
are so small that they do not allow the correct feeding of the strips from the loading
element at the feed rates required by modern assembly lines.
[0008] The aim of the present invention is to solve the above described problems by providing
a device which allows the correct feeding of strips with a conveyor element provided
with traction means arranged at length intervals which are mutually substantially
equal to the dimensions of the strip parallel to the direction of advancement of the
conveyor element.
[0009] Within the scope of this aim, an object of the invention is to provide a feeding
device which can adequately serve a packaging-box assembly line with high productivity.
[0010] Another object of the invention is to provide a device which can be fed with devices
provided with a known loading element and extraction element.
[0011] Another object of the invention is to provide a feeding device which is highly reliable
in operation even at high speeds.
[0012] This aim, these objects and others which will become apparent hereinafter are achieved
by a high-precision strip feeding device, in particular for packaging-box assembling
machines, characterized in that it comprises a first conveyor element which is provided
with strip traction means and which extends from a station for loading said strips
onto said first conveyor element to a station for unloading said strips from said
first conveyor element to a second conveyor element provided with strip traction means,
said first conveyor element extending, at least at said unloading station, so as to
overlap said second conveyor element and having a direction of advancement which is
opposite to the direction of advancement of said second conveyor element.
[0013] Further characteristics and advantages of the invention will become apparent from
the description of a preferred but not exclusive embodiment of the feeding device
according to the invention, illustrated only by way of non-limitative example in the
accompanying drawings, wherein:
figure 1 is a schematic side elevation view of the device according to the invention;
figure 2 is a schematic top plan view of the device;
figure 3 is a front view of the station for loading the strips onto the first conveyor
element;
figures 4 to 6 are schematic side elevation views of the operation of the device according
to the invention; and
figure 7 is an enlarged view of a detail of figure 4.
[0014] With reference to the above figures, the device according to the invention, generally
indicated by the reference numeral 1, comprises a first conveyor element 2 which has
traction means for the strips 3 and extends from a strip loading station 4 to a strip
unloading station 5.
[0015] The first conveyor element 2 is arranged, at least at the unloading station 5, above
a second conveyor element 6 which also has traction means for the strips 3.
[0016] According to the invention, the first conveyor element has, at least at the unloading
station 5, a direction of advancement 7 which is opposite to the advancement direction
8 of the second conveyor element.
[0017] More particularly, the feeding device according to the invention comprises a supporting
framework 9 supporting the first conveyor element, which is constituted by a pair
of chains 10a and 10b extending mutually side by side along a closed path and winding
around a first pair of pinions 11a and 11b, which are both keyed on a shaft 12 arranged
horizontally and rotatably supported by the framework 9 about its own axis, and around
a second pair of pinions 13a and 13b, which have a larger diameter than the pinions
11a and 11b. The pinions 13a and 13b are keyed on coaxial shafts 14a and 14b which
are arranged horizontally and parallel to the shaft 12 and which are rotatably supported
by the framework 9 about their own axes.
[0018] The traction means of the first conveyor element 2 are constituted by raised portions
15 which are applied to links of the pair of chains 10a and 10b and protrude from
the surface defined by the extension of said chains.
[0019] The second conveyor element 6 is substantially constituted by another pair of chains
16a and 16b which are arranged mutually parallel and side by side and wind around
a first pair of pinions 17a and 17b, which are keyed on a same horizontal shaft 18,
and around a second pair of pinions 19a and 19b, which are keyed on another shaft
20 which is horizontal and parallel to the shaft 18. The shafts 18 and 20 are rotatably
supported by the framework 9 about their respective axes.
[0020] The traction means of the second conveyor element 6 are also constituted by raised
portions 21 which are applied to links of the pair of chains 16a and 16b and protrude
from the surface defined by the extension of the chains 16a and 16b.
[0021] The extension of the first conveyor element 2, i.e. of the chains 10a and 10b, is
arranged above the second conveyor element, and guiding means 22 for the strips during
their passage from the first conveyor element to the second conveyor element are provided
proximate to the unloading station 5.
[0022] More particularly, along the direction of advancement of the first conveyor element,
the loading station 4 is arranged on the planar portion of the chains 10a and 10b
upstream of the pinions 13a and 13b, along which the chains follow, for meshing reasons,
a portion of a curved path at the end of which there is the unloading station 5.
[0023] The strip guiding means are arranged along said curved portion of the path followed
by the first conveyor element, and comprise, for each pinion 13a and 13b, two curved
profiled elements 23 and 24 which face one another and follow the curved portion of
the chains 10a and 10b in their meshing with the pinions 13a and 13b, defining a passage
25 for each of the longitudinal ends of the strips 3, which are deposited on the conveyor
element 2 transversely to its direction of advancement and are pushed by the traction
means.
[0024] Each passage 25 is delimited, in the direction of the shaft 14a, 14b, by the substantially
rigid internal profiled element 23, which is fixed to the supporting framework 9 and
has a first portion 23a, the center of curvature whereof substantially coincides with
the axis of the shaft 14a, 14b, and a second portion 23b, at the unloading station
5, which is shaped so as to follow the tangent relative to the end point of the first
portion 23a and subsequently has an opposite concavity with respect to said first
portion 23a, so that an ideal extension thereof is incident with an acute angle with
respect to the plane defined by the underlying second conveyor element 6.
[0025] Externally, i.e. on the side opposite to the shaft 14a, 14b, each passage 25 is delimited
by the external profiled element 24, which has a first portion 24a, which is parallel
to the first portion 23a of the profiled element 23 and is fixed to the framework
9, and a second portion 24b, which faces the second portion 23b of the profiled element
23 and is pivoted about an axis 26 which is parallel to the shaft 14a, 14b so that
it can oscillate toward or away from the second portion 23b. The oscillation of the
second portion 24b of the profiled element 24 away from the profiled element 23 is
biased by a spring 27 which pushes the second portion 24b against the second portion
23b, closing the passage 25.
[0026] The second portion 24b of the profiled element 24 is furthermore shorter than the
second portion 23b of the profiled element 23.
[0027] Advantageously, friction means 28 are arranged along the passage 25 to prevent movements
of the strips due to the force of gravity during advancement along the passage 25.
[0028] In the illustrated embodiment, said friction means are constituted by brushes which
are fixed to the framework 9 and make contact with the longitudinal ends of the strips
3 along the passage 25.
[0029] At the loading station 4 there is a known loading device, for example of the type
disclosed in the above mentioned European Patent Application N. 90119016.5, or a device
provided with a loader 30 in which a plurality of strips 3, stacked above the first
conveyor element 2 and orientated transversely to the advancement direction thereof,
is arranged.
[0030] As is more clearly described in the aforesaid patent application, to which reference
is made for the sake of completeness, said device has an extraction element 31 which
has a tooth 31a which acts in a cyclic manner on the lower strip of the stack to move
it from a first position, in which one of its longitudinal ends 3a rests on a support
32 arranged between the two chains 10a and 10b and the other end 3b is on the extraction
element 31 above the traction means of the chain 10b so that the traction means cannot
engage the strip, to a second position, in which the strip 3 is moved so that its
end 3a is beyond the chain 10a and its end 3b rests on the chain 10b to undergo the
action of the traction means.
[0031] Conveniently, the traction means of the first conveyor element 2 are arranged in
sequence along the extension of the chains 10a and 10b, and the traction means of
the second conveyor element 6 are equally arranged in sequence. The distance between
two successive raised portions 15 of the first conveyor element 2 is greater than
that between two successive raised portions 21 of the second conveyor element 6, and
the advancement speed of the first conveyor element 2 is greater than, and correlated
to, the advancement speed of the second conveyor element 6.
[0032] In order to synchronize the advancement of the first conveyor element 2 with the
advancement of the second conveyor element 6 and with the extraction element 31 it
is possible to provide actuation by means of a single motor, for example a known electric
motor, the output shaft whereof is connected by means of a chain and/or gears to a
gear 33 which is keyed on the shaft 12; said shaft 12 is connected to the extraction
element 31 by means of a bevel gear pair 34-35.
[0033] Said motor actuates the shaft 18 or the shaft 20 of the second conveyor element 6
by virtue of known transmission means which are not illustrated for the sake of simplicity.
[0034] The operation of the feeding device according to the invention is as follows.
[0035] The actuation of the device causes the sequential deposition of strips 3 on the first
conveyor element 2. As mentioned, the distance between two successive raised portions
15 of the first conveyor element is greater than that of said second conveyor element,
so as to allow the correct operation of the device, which loads the strips 3 onto
the first conveyor element 2, arranging each strip between two successive raised portions
15.
[0036] The advancement of the first conveyor element 2 moves the longitudinal ends of the
strips into the passages 25. During transit in the passages 25, the brushes 28 prevent
the partial falling of the strips, keeping each strip against the related raised portion
15 which pushes it.
[0037] Proximate to the unloading station 5, in each instance a strip 3, pushed by the first
conveyor element 2, causes the separation of the second portion 24b from the second
portion 23b to allow the passage of the strip 3, which is guided by the second portion
23b toward the second conveyor element 6.
[0038] By virtue of the fact that the direction of advancement of the first conveyor element
2 in the unloading station 5 is opposite to the direction of advancement of the second
conveyor element 6, the strip 3, in the presence of high advancement speeds, strikes
the first incoming raised portion 21 and falls between said raised portion and the
preceding one, resting on the second conveyor element 6. Any rebounds of the strip
in this step do not interfere with the successive strip which arrives along the passage
25, since each passage 25 has been closed by the return oscillation of the second
portion 24b by virtue of the action of the spring 27.
[0039] The following strip which arrives along the passages 25 is deposited on the second
conveyor element 6 after the raised portion 21 which pushes the preceding strip, and
so forth. In this manner, the strips 3 deposited on the second conveyor element 6
can be fed to an assembling machine with an extremely small distance between the strips.
[0040] In practice it has been observed that the feeding device according to the invention
fully achieves the intended aim since, by virtue of the fact that the directions of
advancement of the two conveyor elements are mutually opposite in the station for
unloading the strips from the first conveyor element to the second conveyor element,
it is possible to place, in each instance, a strip on the second conveyor element
between two traction means which are spaced from one another by a length which is
only slightly greater than the dimensions of the strip along the advancement direction.
In this manner it is possible to feed, by means of the second conveyor element, an
assembling machine with very closely spaced strips and with very high feed rates,
capable of fully exploiting the productivity of the latest assembling machines.
[0041] The feeding device thus conceived is susceptible to numerous modifications and variations,
all of which are within the scope of the inventive concept; all the details may furthermore
be replaced with technically equivalent elements.
[0042] In practice, the materials employed, as well as the dimensions, may be any according
to the requirements and the state of the art.
[0043] 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 scope of each element identified by way of example by such reference signs.
1. High-precision strip feeding device, in particular for packaging-box assembling machines,
characterized in that it comprises a first conveyor element (2) which is provided
with strip traction means (15) and which extends from a station (4) for loading said
strips (3) onto said first conveyor element (2) to a station (5) for unloading said
strips from said first conveyor element (2) to a second conveyor element (6) provided
with strip traction means (21), said first conveyor element (2) extending, at least
at said unloading station (5), so as to overlap said second conveyor element (6) and
having a direction of advancement (7) which is opposite to the direction of advancement
(8) of said second conveyor element (6).
2. Feeding device according to claim 1, characterized in that said traction means comprise
raised portions (15;21) which are applied in sequence along the extension of said
first (2) and second (6) conveyor elements to engage a strip (3) in each instance,
the distance between two successive raised portions (15) on said first conveyor element
(2) being greater than the distance between two successive raised portions (21) of
said second conveyor element (6), the advancement speed of said first conveyor element
(2) being greater than, and correlated to, the advancement speed of said second conveyor
element (6), for the passage of a strip (3), loaded between two successive raised
portions (15) of said first conveyor element (2), onto said second conveyor element
(6) between two successive raised portions (21) thereof.
3. Feeding device, according to claims 1 and 2, characterized in that means (22) for
guiding the strips in their passage from said first conveyor element (2) to said second
conveyor element (6) are provided between said first conveyor element (2) and said
second conveyor element (6) proximate to said unloading station (5).
4. Feeding device, according to one or more of the preceding claims, characterized in
that said first conveyor element (2) and said second conveyor element (6) are constituted
by chains (10a,10b; 16a,16b) wound along closed paths and with said raised portions
(15;21) applied to their links.
5. Feeding device, according to one or more of the preceding claims, characterized in
that said first conveyor element (2), upstream of said unloading station (5), extends
along a portion of a curved path which is arranged above said second conveyor element
(6), said guiding means (22) comprising two curved profiled elements (23,24) which
face one another and define a curved passage (25) followed by the strips (3) pushed
by the traction means (15) of said first conveyor element (2), said passage (25) leading
onto said second conveyor element (6) along a direction which is incident, at an acute
angle, to the plane of arrangement of said second conveyor element (6).
6. Feeding device, according to one or more of the preceding claims, characterized in
that said passage (25) is internally delimited by a substantially rigid internal profiled
element (23) which has a first portion (23a), the center of curvature whereof substantially
coincides with the center of curvature of said curved path of said first conveyor
element (2), and a second portion (23b), at said unloading station (5), which is shaped
substantially so as to follow the tangent relative to the end point of said first
portion (23a) to guide the strips (3) onto said second conveyor element (6).
7. Feeding device, according to one or more of the preceding claims, characterized in
that said passage (25) is externally delimited by an external profiled element (24)
which has a first portion (24a), which is substantially parallel to the first portion
(23a) of the internal profiled element (23), and a second portion (24b), which faces
the second portion (23b) of the internal profiled element (23), said second portion
(24b) of the external profiled element (24) being movable toward or away from said
internal profiled element (23) by virtue of the action of, or in contrast with, elastic
return means (22) for the cyclic closure of said passage (25) after the delivery of
a strip (3) from said first conveyor element (2) to said second conveyor element (6).
8. Feeding device, according to one or more of the preceding claims, characterized in
that the terminal part of the second portion (23b) of said internal profiled element
(23) has a concavity which is opposite with respect to the remaining part of said
internal profiled element (23).
9. Feeding device, according to one or more of the preceding claims, characterized in
that friction means (28) for said strips (3) are arranged along said passage (25)
to retain each strip (3) against the related raised portion (15) of the first conveyor
element (2).
10. Feeding device, according to one or more of the preceding claims, characterized in
that said friction means are constituted by brushes (28) which make contact with the
transverse ends of the strips (3) during their transit in said passage (25).