Note: Descriptions are shown in the official language in which they were submitted.
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SCREWING ASSEMBLY FOR SCREWING CLOSING PLUGS ONTO
SYRINGES
The present invention relates to a screwing
assembly for screwing closing plugs onto syringes.
In the injectable pharmaceutical product
preparation, it is known to make a machine comprising at
least one store for a plurality of containers (bags,
syringes and bottles, in the case in point); at least
one dosing station for the preparation of pharmaceutical
product obtained by feeding into a syringe a
pharmaceutical taken from a bottle and diluent taken
from a bag; and a gripping and conveying device for
transferring the containers between the store and the
dosing station.
The syringe comprises a containment cylinder, a
plunger engaged in sliding manner in the containment
cylinder and a needle snap-locked onto an open end of
the containment cylinder itself.
After having prepared the pharmaceutical product in
the syringe, the needle is removed from the syringe and
the open end is sealed by means of the closing plug in
order to allow medical personnel to safely handle the
syringe itself.
Because the closing plug is normally snap-locked on
the open end of the syringe, the known machines for the
preparation of pharmaceutical products of the type
described above have some drawbacks mainly deriving from
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the fact that the closing plug and the syringe are moved
against each other with a relatively high coupling
force, which may damage both the closing plug and the
open end of the containment cylinder, thus preventing
the subsequent assembly of a new needle.
Furthermore, the known machines for the preparation
of pharmaceutical products of the type described above
do not allow the use of threaded closing plugs and thus
have a relatively low flexibility of use.
It is the object of the present invention to
provide a screwing assembly for screwing closing plugs
on syringes which is free from the above-described
drawbacks and which is simple and cost-effective to
implement.
According to the present invention, a screwing
assembly for screwing closing plugs onto syringes is
provided as disclosed in the appended claims.
The present invention will now be described with
reference to the accompanying drawings, which illustrate
a non-limitative embodiment thereof, in which:
figure 1 is a perspective diagrammatic view, with
parts removed for clarity, of a preferred embodiment of
the screwing assembly of the present invention;
figure 2 is a diagrammatic plan view of a detail in
figure 1; and
figure 3 is an exploded perspective view of the
detail in figure 2.
With reference to figures 1, 2, and 3, numeral 1
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indicates as a whole a screwing assembly for screwing
closing plugs 2 of substantially quadrilateral shape
onto syringes 3 of known type, each of which has a given
longitudinal axis 4 and comprises a containment cylinder
5, which is provided with a externally threaded open end
6, and is slidingly engaged by a plunger 7.
In the case in point, the plugs 2 are designed so
as to be absolutely tamperproof during handling of the
syringes 3 containing the pharmaceutical product to be
administered to patients.
The screwing assembly 1 comprises a boxed frame 8
closed on the top by a containment hopper 9 for a
plurality of plugs 2 arranged within the hopper 9 with
their concavities facing upwards.
The hopper 9 comprises a vibrating plate 10, which
has a substantially rectangular shape, defines a support
plane P for the plugs 2 inclined according to a given
angle with respect to a substantially horizontal
reference plane, and has an outlet hole 11, which is
obtained through a lower end of the plate 10, and has a
longitudinal axis 12 substantially perpendicular to the
plane P itself.
The plate 10 is slidingly coupled to the frame 8
with the interposition of a shock absorber device 13 to
perform rectilinear movements in a direction 14
substantially parallel to axis 12 with respect to the
frame 8, and is additionally coupled in sliding manner
to the frame 8 to move with respect to the frame 8 and
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under the bias of an actuating device 15, with a
reciprocating rectilinear motion in a substantially
horizontal direction 16 transversal to direction 14.
Device 13 comprises, in the case in point, four
elastic elements 17 mounted between frame 8 and plate 10
at the vertexes of the plate 10 itself; and the device
comprises an electromagnetic actuator 18, which is
fixed within the frame 8 parallel to direction 16, and
has an outlet rod 19 connected to a coupling bracket 20
10 protruding downwards from the plate 10.
The hopper 9 is limited on the side by a hollow
plate 21, which is fork-shaped, is fixed onto the plate
10 to define an advancement channel 22 of the plugs 2
along the plane P and towards the hole 11, and is shaped
15 so as to divide the channel 22 into a lower
substantially rectilinear outlet section 22a connected
to the hole 11 and an upper inlet section 22b converging
towards section 22a.
Channel 22 cooperates with a first stop device 23
comprising an actuating cylinder 24, which is mounted
inside the plate 21 parallel to direction 16, and has an
output rod 25 mobile between a rest position, in which
the rod 25 is substantially contained in the plate 21,
and an operating position, in which the rod 25 protrudes
into the section 22a to prevent the plugs 2 from
reaching the inside of the section 22a itself.
The channel 22 further cooperates with a second
stop device 26, comprising an actuating cylinder 27,
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which is mounted inside the plate 21 parallel to
direction 16, and has an output rod 28 mobile between a
rest position, in which the rod 28 is substantially
contained in the plate 21, and an operating position, in
5 which the rod 28 protrudes into the section 22a
downstream of the rod 25 to prevent the plugs 2 from
reaching the hole 11.
With regards to this, it is worth specifying that
the movement of the rods 25 and 28 in their operating
positions defines a compartment adapted to accommodate a
single plug 2 therein.
The screwing assembly 1 further comprises a support
device 29 of a syringe 3, e.g. a robotized arm, adapted
to keep the syringe 3 in position coaxial to the axis
12, and a support device 30 adapted to receive the plug
2 fed each time through the hole 11.
The device 30 comprises a pocket 31, which is
mounted inside the frame 8, under the plate 10, and in
position facing the hole 11, is limited by a bottom wall
32, which has a quadrilateral shape substantially
corresponding to the shape of the plugs 2, and which
extends perpendicular to direction 14, and is further
limited by a quadrilateral side wall 33, which extends
about axis 12, and is inclined according to an angle
other than 90 with respect to the wall 32 itself.
The pocket 31 is mounted on the free end of the
outlet shaft 34 of an electric motor 35, which is
mounted within the frame 8 parallel to direction 14, is
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fixed to the hopper 9 under the plate 10, is adapted to
move the pocket 31, with respect to the plate 10 itself,
about axis 12, and is torque-controlled so as to allow
the correct screwing of the plugs 2 onto the respective
syringes 3.
The shape of the pocket 31 and of the lower outlet
section 22a of the channel 22 allows the plugs 2 to drop
through the hole 11 so as to be aligned with, and
correctly inserted in the pocket 31 itself during the
rotation about the axis 12.
The operation of screwing assembly I will now be
described with reference to figures 1, 2 and 3 starting
from an instant in which:
the syringe 3 is moved by the device 29 to a
position coaxial to axis 12;
the stop devices 23, 26 are arranged in their
operating positions; and
the outlet section 22a of the channel 22 is empty.
Device 23 is firstly moved to its rest position to
allow a plug 2 to drop into the section 22a and is then
moved again to its operating position to prevent other
plugs 2 from dropping into the section 22a itself.
The device 26 is thus moved to the rest position
thereof to allow the considered plug 2 to reach the hole
11 and fall into the pocket 31.
At this point, the syringe 3 is lowered by the
device 29 so as to allow the open end 6 of the syringe 3
to engage the plug 2 and to move the assembly defined by
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the hopper 9 and by the pocket 31 against the bias of
the elastic elements 17 of the shock absorbers device
13.
Finally, the pocket 31 and thus the plug 2 are
moved about the axis 12 by the actuation of the electric
motor 35 and along the axis 12 by the bias of the
elastic element 17 of the shock absorber device 13. In
other words, the pocket 31 and the plug 2 are moved with
roto-translating movement about and along the mentioned
axis 12 in order to screw the plug 2 onto the open end 6
of the syringe 3.
With regards to the above, it is worth noting that
the pharmaceutical product contained in the syringe 3
does not exit from the end 6 due to the surface tension
and the capillarity of the cylinder 5 at the open end 6
itself.
