Patent Application
20210139304
This application claims the priority benefit of Italian Pat. App. No. 102019000020730, filed on Nov. 11, 2019, which is fully incorporated by reference herein in its entirety.
The present invention relates to a capping machine equipped with a plurality of capping heads with roto-translation movement.
Capping machines comprise a plurality of capping heads which, in the case of screw caps or in certain capping modes, not only require a translation movement from the top downwards—so as to couple the cap with the neck of the container to be capped—but also a rotation movement.
Conventional capping machines may use, for this purpose, a motor connected to a nut screw on which a nut slides. The nut is then anchored to the capping element which is thus subjected to a roto-translation movement adapted to operate the desired capping. This system may be used if the rotation movements are controlled individually.
Another implementation may involve the use of a single motor for the rotation which, by means of the use of a belt, imparts the rotation to all the heads of the carousel. In this case, the torque control, to determine if the capping has been reached, is carried out by means of a preloaded clutch mounted on each individual head, which releases the rotation at the set tightening torque.
Such machines, however, although easily configured, have the disadvantage that, in the event of downtime of the machine and/or of the motor being uncoupled, and if the need arises to lift the capping head to allow the area below to be inspected, such lifting must overcome a very high torque, therefore it may be impossible to proceed with the simple movement of the hand or in some cases also due to the interference of a cam.
Roto-translating motors exist which are provided with high compactness and precision; although, such motors have the defect of including the rotor magnets inside the roto-translating shaft, which severely limits the space available for the various utilities, such as air, vacuum or even an ejector.
An object of the invention is a capping head comprising the technical features set out in one or more of the appended claims, the definitions of which form an integral part of the present description.
It is a further object of the invention a capping machine comprising a plurality of the capping heads in accordance with the invention.
Further features and advantages of the present invention will become more apparent from the following indicative and thus non-limiting description of a preferred, but not exclusive, embodiment of the invention.
The capping device 4 is partially shown in
The supporting structure 2 comprises an upper plate 2a, a lower plate 2b and one or more uprights 2c which connect said upper 2a and lower plates 2b. The supporting structure 2 will further comprise means for the fastening to a carousel 101 (shown in
The roto-translation system 3 is placed between the two plates 2a, 2b and comprises a linear motor 3a and a rotary motor 3b operatively coupled so as to impart a roto-translation motion to the capping device 4.
The rotary motor 3b is preferably a brushless electric motor, more preferably a torque motor, of the conventional type and comprises a casing 7 which contains a rotor 6a, externally coupled to the capping device 4, and a stator 6b.
In certain embodiments, the casing 7 of the rotary motor 3b is connected to a pipeline 8 which provides the desired utility, such as air or vacuum, to the hollow rod 4a of the capping device 4 by means of a suitable junction 8′. The pipeline 8 is fastened to the casing 7 and slides upwards or downwards together with the rotary motor 3b. The sliding of the pipeline 8 occurs by means of a hole 9 arranged on the upper plate 2a of the supporting structure 2, which acts as a guide.
The rotary motor 3b further comprises a sliding portion 5 which is slidable on a guide vertically arranged on the uprights 2c, so as to allow the vertical sliding of the rotary motor 3b. The sliding portion 5 is coupled for a movement integral to a loop member 10, such as a belt, a toothed belt or a chain. The loop member 10 is in turn coupled with an upper pulley 11a and a lower pulley 11b, idly hinged on the uprights 2c of the supporting structure 2, and has a front side 10b, on which the sliding portion 5 of the rotary motor 3b is coupled, and a rear side 10a.
The linear motor 3a comprises a stator 12a and a movable member 12b. The stator 12a is fastened to the uprights 2c and longitudinally extends between the upper plate 2a and the lower plate 2b. The movable member 12b is instead fastened on the rear side 10a of the loop member 10, so that, when the rotary motor 3b is in a raised position, in which the capping device is disengaged from the neck of a container to be capped, the capping device 12b is in a lowered position, and vice versa.
This configuration allows to obtain a counterweight for the rotary motor 3b, so as to keep it in a raised position even when the linear motor 3a is in an error condition, whereby it is unable to control the movement of the rotary motor 3b.
A further advantage of this solution, in addition to the fact that the movable member of the linear motor is a counterweight for the torque motor, is that, by virtue thereof, the linear motor is balanced (as if it worked horizontally) and it is therefore possible to perform a torque sizing (therefore sizing dimensions and weight) much lower with respect to the case with the torque motor directly mounted on the movable member of the linear motor with the additional counterweight.
In the case where the weight of the movable member 12b is substantially different from that of the rotary motor 3b, it will be possible to provide a load on the movable member 12b or on the rotary motor, as appropriate.
Thereby, a suspension system is obtained which is adapted to keep the rotary motor 3b in a raised position even when the linear motor 3a is malfunctioning, for example, if the electromagnetic field fails or if an electromagnetic decoupling occurs between the stator and the movable member.
In a different embodiment, not shown in the Figures, the movable member 12b is fastened to the front side 10b of the loop member 10 and to the sliding portion 5 of the rotary motor 3b, while, on the rear side 10a of the loop member 10, the movable member 12b is replaced by a ballast of suitable weight so as to obtain said rotary motor suspension system 3b. Thereby, the movable member 12b of the linear motor 3a rises and lowers together with the rotary motor 3b, while the ballast provides the counterweight necessary to keep the rotary motor 3b together with the movable member 12b in a raised position even in the event of disengagement of the linear motor.
The capping head 201 comprises, similarly to the embodiments described above, a supporting structure 2 on which a roto-translation system 3 for a capping device 4 is mounted.
The supporting structure 2 and the capping device 4 are entirely similar to those described above. The roto-translation system 3 in turn comprises a linear motor 3a and a rotary motor 3b, in which the rotary motor 3b and the movable member of the linear motor 3a are enclosed in the same casing 7, while the stator 12a of the linear motor 3a is fastened on one or more uprights 2c of the supporting structure 2. The casing 7 comprises a sliding portion 7′ adapted to slide on a profile 212 of the stator 12a.
On the upper surface 7a of the casing 7 there is a rod 13 which passes through the upper plate 2a of the supporting structure 2 and ends with a wheel 14 adapted to slide on a cam (not shown), which acts as an emergency lifting means of the capping device 4, in the event that an inconvenience or malfunction occurs.
The embodiment of
Therefore, when, during the operating step of the capping head 201, it is necessary to bring the capping device 4 downwards, the linear motor 3a will act against the resistance operated by the springs 16. In case of error or disconnection of the linear motor 3a, the springs 16 will automatically return the rotary motor 3b—and therefore also the capping device 4—to a raised position.
In case of unbalance (movable member of the linear motor lighter than the torque motor), the balancing solution in case of intervention of the safety cam may be reached without ballasting the system (as described above), but simply by ensuring that the safety cam raises the torque motor to a level higher with respect to the normal working one, and by arranging a magnet above the motor so as to keep the motor in a raised position until the working conditions are restored. Upon restarting, the motor itself will disconnect the system from the safety magnet.
In such embodiment, therefore, the rotary motor 3b comprises, on the upper surface 7a of the casing 7, a safety magnet to keep the rotary motor 3b, following said emergency lifting, in a raised position.
The capping machine 101 is, per se, of the conventional type and comprises a carousel 120. The carousel 120 comprises a central axis 121, on which a discoidal plate 122 is integrally supported, on the edge of which the capping heads 1, 201 of the invention are installed. The capping devices 4 cross the discoidal plate 122 and are arranged on a support (not shown) which is coaxial with respect to the discoidal plate 122, on which the containers to be capped are held in rotation.
The central axis 121 of the carousel 120 is set in rotation by a motor drive (not shown).
The invention achieves the intended objects, as it allows to impart a roto-translation motion to the capping device 4, without the aid of worm screws, but by virtue of the coupling of a rotary motor with a linear motor.
At the same time, the technical solution adopted in the present invention allows to provide a suspension system for the motor drive unit, in particular for the rotary motor to which the capping device is associated, which allows the automatic or manual lifting of the capping device and the maintenance thereof in a raised position even in case of disconnection of the linear motor in charge of the vertical movement of the capping device itself.
An additional advantage is torque control. In a conventional roto-translating solution, the rotating member incorporates components which are used not only for the rotation, but also for the translation; thereby, the inertia of the rotor will be greater, and therefore it will be more difficult to achieve a control which accurately determines the tightening torque of the screw caps. In the invention, in which the translation has been decoupled from the rotation, the shaft of the rotary motor only comprises elements which are functional for the rotation, thereby it will have a lower inertia with respect to the conventional solution and therefore the tightening torque control will be easier to achieve, more precise and more effective.
Clearly, only a few particular embodiments of the present invention have been described, so a person skilled in the art will be able to make all of the necessary changes for the adaptation thereof to particular applications, without thereby departing from the scope of protection of the present invention. For instance, and by way of example only, it is understood that the appended claim 14 could recite a capping machine comprising a carousel on which a plurality of capping heads according to any one of claims 1-13 is mounted.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102019000020730 | Nov 2019 | IT | national |
