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The present invention relates to the large number
production of metallic cans by means of pressing.
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Particularly the present invention concerns to a stock
feeding device of a press for producing covers for such
cans from substantially flat disks, this last processing
also known as "conversion" of said covers.
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It is known that, for carrying out steel or aluminium
cans, used mainly for containing preserved foods or drinks,
presses opportunely arranged for making the can components,
and eventually for assembling more components, are used.
Particularly, for producing opening tab covers, presses are
normally used, fit to form the cover progressively from a
circular shell, in correspondence of consecutive moulding
dies, while the shell is carried step by step on a
continuous conveyor belt. Such belts carry the shells on
one or more parallel lines, consecutively in correspondence
of related die lines where the shells are progressively
converted. During the conversion process the press also
applies a tab to the cover, fit to facilitate the can
opening, in correspondence of a suitable die. Tabs are
provided by a feeding device, arranged transversally to the
shell conveyor belt and to the dies, disposing each tab at
the exact position in correspondence of the related forming
cover, with phase relationship with the operation of the
other press components. Tabs are generally made by a known
device, near the press, on a continuous belt of metallic
sheet, and are carried immediately toward the feeding
device. Alternatively the continuous belts with already
preformed tabs are made elsewhere and supplied subsequently
to feeding device. Tabs are arranged consecutively in the
belt, and are eventually placed side by side on more lines,
according to the press configuration. Once the tabs are
applied, their working scraps, namely the belt residues,
are triturated and carried elsewhere.
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The US-A-4.723.882 describes a tab feeder device
comprising a plate, which is bolted to the press frame. The
crankshaft of the tab feeder is coupled to a gearing, which
is connected to a driveshaft and a gear box providing a
change of the motion direction. Such gear box is connected
to a second crankshaft by a belt, which is driven by the
main crankshaft of the press.
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Also the US-A-4.568.230 describes a tab feeder in a
press for converting covers of cans and the like. The
feeder is mounted on the press bed and slide, so as the
forces are distributed in substantially symmetrical manner
over the opposed working areas of the bed and slide. It
receives the intermittent rotary motion from the press
power shaft, by means of a gear box and belts.
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A rather common drawback of the known tab feeding
devices consists in that, for own nature, tab belts have
the tendency to get jammed in the transport and application
mechanisms. In that case the presses must be stopped, the
jammed tabs must be eliminated and the belt correctly
replaced. For doing these operations the feeding device,
which is arranged transversally to the cover feed axle,
must be removed from the own working position, and
therefore replaced at the end of the maintenance. This is a
rather long and complex operation, since the belts, leading
the motion to the feeder device members, must be detached,
so losing their phase relationship, that must be restored
and verified before restarting the press. This fact causes
obviously serious decreases of press productivity, which is
a particularly expensive apparatus, and therefore
remarkable economic damages.
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The EP-0.397.750 discloses a tab feeding device whose
carrier is pivoted at a suitable hinge axle. The whole
device, comprehensive of driving and tab feeding means, may
be therefore pivoted to allow the access to press by an
operator, without losing the phases.
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The above described device shows however a fair
realization complexity and is rather critical in setting.
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The object of the present invention is to propose a tab
feeding device of a press for producing can covers fit to
be easily removed, allowing the access to the press, and
therefore immediately replaced without losing working
phases.
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Further object of the present invention is to propose a
motion of said feeding device having simple realization,
low cost and high reliability.
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The above mentioned objects are reached according to
the claims.
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The characteristics of the invention are underlined in
the follow with particular reference to attached drawing
tables, where:
- figure 1 shows schematically a side view of the
device of the invention, joined to a relative press, at its
working position;
- figure 2 shows a plan view of the same device, still
at working position;
- figure 3 shows a view according to figure 1, with the
feeding device in opening position;
- figure 4 shows the view of figure 2, with the feeding
device still in opening position;
- figure 5 shows schematically a front view of the
device.
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Referring to figures 1 and 2, with 1 is indicated a
press fit to working pieces 3, particularly circular
shells, for getting correspondent converted covers,
according to known manner, not described in detail.
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The press 1 is provided with mean feeding members 2 of
the pieces 3, constituted by an endless conveyor belt
having consecutively housing lines, designed to housing
said pieces 3 and transporting them progressively toward
following known working stations. The main feeding members
2 are moved step by step by main motion means 4,
constituted by a reduction unit connected to the press
power members through a belt 4a.
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Said work stations are supported by the base 7 of the
press 1, substantially constituted by a bed 7a and by a
bolster 7b, overhanging the bed 7a. Work stations include a
die series forming the converted cover progressively from
the circular shell. In correspondence of an intermediate
work station, a stock constituted by a tab is applied to
the cover 3. This tab is fed step by step by the feeding
device 10 object of the invention, with a phase
relationship with the driving of the main feeding members
2.
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Such device is placed laterally to the press 1. It
comprises substantially an input tab group 11, fixed on the
horizontal plate 15a of an L-shaped frame 15 (see also
figure 5) and designed to feed transversally the press 1
with a belt containing the preformed tabs; an output group
12, fixed to the same horizontal plate 15a; a plurality of
drive belts 17, engaged with said input 11 and output 12
groups, and with first motion drive members 13, joined to
the vertical plate 15b of said frame 15.
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These latter are constituted by a motion return group
of gear-wheel type, engaging slidingly and sideways driving
engaged members 30. These are constituted by a spline shaft
31, horizontally placed in a position substantially
parallel to said main feeding members 2 and supported by a
couple of sphere bearings 32a,32b, fixed to the base 7 of
the press 1.
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The spline shaft is connected, at an end with the main
motion means 4 previously mentioned.
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The feeding device 10 has also drive means 20,
slidingly supporting the feeding device, at a direction
parallel to the mean feeding members 2, between an
operative extreme position A (see figures 1 and 2) and an
inoperative extreme position B (figures 3 and 4), at which
said device is carried for allowing inside access to the
press 1.
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The drive means 20 are constituted by a couple of
parallel slides, respectively upper 21 and lower 22, fixed
longitudinally and laterally to the base 7 of the press 1.
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The slides 21,22 slidingly engage correspondent splined
sliders 16a,16b,16c, opportunely fixed to the vertical
plate 15b of the frame 15.
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The operation of feeding device 10, particularly
concerning its motion for allowing inside access to the
press 1, is quite intuitive.
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With reference to figures 1 and 2, the frame 15 is in
the operative extreme position A, that is the normal
operation of the device 10. In such position the spline
slider 16b is next to the end of upper slide 21, while the
spline slider 16c is next to the end of the lower slide 22.
The gear-wheel of the return group 14 engages the spline
shaft 31 next to the end of this latter that is more
distant from the main motion means 4.
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As figures 3 and 4 show, the device 10, after having
been carried in its inoperative extreme position B, has the
gear-wheel of the return group 14 engaging the spline shaft
31 near to the end of this latter connected to the main
motion means 4. It is evident that, with the device 10 in
this latter position, the access to the inside parts of the
press 1 is entirely free.
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The above said description show that this particular
coupling between the spline shaft 31 and the motion return
group 14, in association with the coupling among the slides
21,22 and the corresponding spline sliders 16a,16b,16c,
ensure the connection of the feeding device 10 to the main
motion means 4 for the whole run of the device between the
extreme operative position A and inoperative B.
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An advantage of the invention consists firstly in
having got an extremely simple motion of the feeding device
10, and therefore reliable and with lower production costs.
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Besides, such a type of motion allows to free the press
access independently by the dimensions of the device 10,
since the excursion of this last depends exclusively on the
dimensions of the slides 21,22 and of the spline shaft 31.
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Finally, it is also evident that with the proposed type
of motion there is not in every case any stress on the
different motion transmission belts of the feeding device
10.
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It is understood that all above described is by way of
example not restrictive, therefore possible constructive
alterations are included within the present technical
solution, as above described and in the follow claimed.
