Actuation unit for a capping head and capping head using it

Abstract

An actuation unit for a capping head for the application of caps on containers or bottles, as well as to a capping head using such a unit, are provided. The actuation unit for a capping head for the application of caps on containers or bottles comprises at least two actuators, of which a first actuator is adapted to impart a translational displacement along a closing axis and a second actuator is adapted to impart a rotational movement about the closing axis, each actuator of the at least two actuators causing the rotation of a first shaft and a second shaft, respectively, both arranged coaxial to the closing axis, and is characterized in that the shafts of the at least two actuators are placed side by side along the axis and are mutually connected by means of at least one rotation decoupling joint.

Claims

1. An actuation unit (10) for a capping head for the application of caps on containers or bottles, comprising: at least two actuators (11, 12) of which a first actuator (11) is adapted to impart a translational displacement of a first shaft (13) along a closing axis (A) and a second actuator (12) is adapted to impart a rotational movement about the closing axis (A), each actuator (11, 12) of the at least two actuators (11, 12) causing the rotation of the first shaft (13) and a second shaft (14), respectively, both arranged coaxially to the closing axis (A), wherein the shafts (13, 14) of the at least two actuators (11, 12) are placed side by side along the axis and are mutually connected by at least one rotation decoupling joint (20) and wherein the rotation decoupling joint (20) is fixedly constrained between the two shafts (13, 14) in respect of axial translation of both shafts (13, 14), whereby the translational displacement imparted to the first shaft (13) by the first actuator (11) is transferred to the second shaft (14), wherein the first shaft (13) of the first actuator (11) is placed above the rotation decoupling joint (20) and the second shaft (14) of the second actuator (12) is placed below the rotation decoupling joint (20), the second shaft (14) having a top end with a box-shaped portion (30) in which the rotation decoupling joint (20) is retained; and wherein the second shaft (14) of the second actuator (12) comprises a first part (23) of which an upper end is connected to the rotation decoupling joint (20) and a lower end is provided with a grooved portion (23a) with radial grooves that run parallel to the closing axis (A), and a second part (24) fixed with respect to axial translation and shaped in complementary manner to the grooved portion (23a) of the first part (23), the first part (23) being movable and constrained to slide inside the second part (24) of the second shaft (14) of the second actuator (12) under the action of the first actuator (11), the second part (24) being hollow and integrally carrying a rotor (18) of the second actuator (12) and causing rotation of the first part (23).

2. The actuation unit (10) according to claim 1, wherein the rotation decoupling joint (20) comprises an orientable bearing (28) in order to allow a relative orientation between the two shafts (13, 14).

3. The actuation unit (10) according to claim 1, wherein the first shaft (13) comprises: a hollow tubular body (22) having an axis parallel to the closing axis (A) and comprising at least one portion (19) having an inner thread, the hollow tubular body (22) integrally carrying a rotor (17) of the first actuator (11); and a rolling screw (21) accommodated inside the hollow tubular body (22) and coupled to the at least one portion (19) having an inner thread thereby providing a screw-nut coupling.

4. The actuation unit (10) according to claim 3, wherein the rolling screw (21) is connected to anti-rotation means (27, 31, 32), adapted to prevent the rolling screw (21) from rotating about its axis, but adapted to allow an axial translation of the rolling screw (21).

5. The actuation unit (10) according to claim 4, wherein, when a torque exceeding a threshold torque is applied to the rolling screw (21), the anti-rotation means (27, 31, 32) is deactivated.

6. The actuation unit (10) according to claim 5, wherein the anti-rotation means (27, 31, 32) comprise at least one magnetic or ferromagnetic element (31) fixedly connected to the rolling screw (21) and magnetically coupled to a respective magnetic or electromagnetic track (32) fixedly constrained along a direction parallel to the closing axis (A).

7. The actuation unit (10) according to claim 4, wherein the anti-rotation means (27, 31, 32) comprise at least one magnetic or ferromagnetic element (31) fixedly connected to the rolling screw (21) and magnetically coupled to a respective magnetic or electromagnetic track (32) fixedly constrained along a direction parallel to the closing axis (A).

Description

(1) In the drawings:

(2) FIG. 1 is an axonometric view of a first preferred embodiment of an actuation unit for a capping head for the application of caps on containers or bottles according to the present invention;

(3) FIG. 2 is a partially open axonometric view of the actuation unit shown in FIG. 1;

(4) FIG. 3 is a sectional axonometric view of the actuation unit shown in FIG. 1;

(5) FIGS. 4 and 4a are a plan sectional view of the actuation unit shown in FIG. 1 and an enlarged detail thereof, respectively;

(6) FIGS. 5 and 6 are a plan sectional view and an axonometric sectional view, respectively, of a detail of a second embodiment of the actuation unit for a capping head according to the present invention;

(7) FIGS. 7 and 8 are an axonometric sectional view and a plan sectional view, respectively, of a third preferred embodiment of an actuation unit for a capping head according to the present invention.

(8) In the following description, for explaining the Figures, the same reference numerals are used to denote constructive elements having the same functions. Moreover, for the sake of clarity of the illustration, it is possible that some reference numerals are not shown in all Figures.

(9) Referring to FIGS. 1 to 4, there is shown a first preferred embodiment of an actuation unit for a capping head for the application of caps on containers or bottles according to the present invention, denoted in the whole by reference numeral 10.

(10) Actuation unit 10 includes a housing 25 inside which two actuators 11, 12 are housed, of which a first actuator 11 is adapted to provide, at the output of actuation unit 10, a translational displacement along a main closing axis A and a second actuator 12 is adapted to provide at the output a rotational movement about closing axis A.

(11) More particularly, in the embodiment shown in FIGS. 1 to 4, housing 25 is formed of several parts, thereby allowing a modular construction of actuation unit 10.

(12) Even if this is not shown, actuation unit 10 is used in association with a capping head including in addition cap gripping means (not shown) connected below actuation unit 10 and adapted to grip and internally retain a cap (not shown) in order to bring it in correspondence of a container to be capped (not shown).

(13) Actuation unit 10 acts on the cap gripping means so as to position and tightly seal the cap on the container mouth through the movements imparted along and about closing axis A.

(14) More particularly, during an exemplary capping cycle, the cap gripping means are first translated downwards along closing axis A in order to reach the container mouth. Subsequently, a rotation of the gripping means takes place in order to tightly screw the cap on the mouth of the container, and lastly the gripping means are translated back upwards along closing axis A in order to become released from the container on which the cap is tightly sealed and to allow taking off the container.

(15) Clearly, other movement sequences combining a rotational and a translational movement are possible depending on the particular capping modality to be implemented.

(16) In addition, actuation unit 10 can act on the gripping means so as to perform also a forced ejection of a cap possibly remaining in the gripping means at the end of the capping operation, or to give a command for opening and/or closing a manipulator and/or a pincer.

(17) Each actuator 11, 12 is a rotary actuator and acts on a respective shaft 13, 14 arranged coaxially to closing axis A. To this end, each actuator 11, 12 includes a respective electromagnetic stator 15, 16, fixedly connected to housing 25 and cooperating with a respective magnetic rotor 17, 18, integrally carried by the corresponding shaft 13, 14.

(18) According to the present invention, shafts 13, 14 of both actuators are superimposed and are mutually connected by means of a rotation decoupling joint 20.

(19) More particularly, shaft 13 of the first actuator 11, or first shaft 13, includes a tubular outer body 22 with axis parallel to closing axis A, fixedly connected to a coaxial internally threaded nut member 19.

(20) The first shaft 13 further includes a recirculating ball screw 21 housed inside outer tubular body 22 and coupled with nut member 19 in such a manner that a rotation of nut member 19 causes a translation of recirculating ball screw 21.

(21) Recirculating ball screw 21 is connected at is lower end to rotation decoupling joint 20, which is to make rotation of the first shaft 13 independent of that of shaft 14 of the second actuator 12, or second shaft 14.

(22) More specifically, decoupling joint 20 is adapted to allow a relative rotation between the second shaft 14 and recirculating ball screw 21 of the first shaft 13, the rotational movement of which is prevented by anti-rotation means. An exemplary embodiment of the anti-rotation means is disclosed in connection with the embodiment shown in FIGS. 5 and 6, which will be referred to in more detail later on.

(23) Moreover, decoupling joint 20 is adapted to connect coaxial shafts 13, 14 so as to prevent a relative translation thereof. This is necessary in order to provide at the output the linear position control imparted by the first actuator 11.

(24) The second shaft 14 is made of two parts and comprises a movable first part 23, which is connected at its upper end to rotation decoupling joint 20 as disclosed above, and is equipped at its lower end with a grooved portion 23a with radial grooves extending parallel to closing axis A.

(25) The first part 23 is constrained to slide inside a second part 24 of shaft 14 of the second actuator 12, carrying magnetic rotor 18. To this end, the second part 24 of the shaft is hollow and is internally provided with grooves complementary to grooved portion 23a of the first part 23.

(26) A connecting member 33, shown in more detail in FIG. 4a, is provided at the bottom end of the second shaft 14, between the first and the second shaft portions 23, 24. That member allows a relative translation between the two portions 23, 24, while causing a mutual rotation thereof. More specifically, in the embodiment shown in FIG. 4a, connecting member 33 is a grooved bushing.

(27) Resilient members 34 adapted to ensure an upward return of shafts 13, 14 in case of deactivation of the first actuator 11 are axially interposed between the first and second actuators 11, 12.

(28) FIGS. 5 and 6 show a second embodiment including a preferred construction of decoupling joint 20, which comprises a double ball bearing 28 connected to both shafts 13, 14 through a threaded ferrule housing 29.

(29) Threaded ferrule housing 29 is screwed on recirculating ball screw 21, it too threaded, in correspondence of an abutment portion 21a of the same screw 21, located at the lower end of screw 21.

(30) Moreover, threaded ferrule housing 29 is housed within a box-shaped portion 30 of the second shaft 14, located at the upper end of the same shaft 14 and joined to the same shaft 14 through a threaded connection.

(31) Box-shaped portion 30 of the second shaft 14 is open upwards in order to allow introduction of the bottom end portion of recirculating ball screw 21 and of the threaded ferrule. Moreover, an upper cover 38 is provided, which is joined to box-shaped portion 30 through a threaded connection so as to define a sealing seat in which threaded ferrule housing 29 is retained together with the bottom end portion of recirculating ball screw 21.

(32) In this manner, decoupling joint 20 is retained between abutment portion 21a of recirculating ball screw 21 and upper cover 38 joined with box-shaped portion 30 of the second shaft 14, whereby it is capable of preventing a relative axial translation of shafts 13, 14.

(33) Double ball bearing 28 acts against the internal walls of box-shaped portion 30 of the second shaft 14, thereby allowing a relative rotation of shafts 13, 14.

(34) According to the preferred construction of decoupling joint 20 shown in FIGS. 5 and 6, the joint includes an orientable bearing 28 such as to allow a minimum relative orientation between shafts 13, 14. To this end, ball seat 28a is rounded.

(35) Referring to FIGS. 5 and 6, there are shown in detail also the anti-rotation means preventing recirculating ball screw 21 from rotating about its axis, while allowing however axial translation thereof relative to external housing 25.

(36) Such means include a plate 27 which is fixedly connected to recirculating ball screw 21 and which is acted upon by resilient means 34. Plate 27 is connected to external housing 25 so as to be axially slidable, but its rotation relative to said external housing 25 is prevented. In this manner, a rotational movement of recirculating ball screw 21 relative to external housing 25 is prevented.

(37) In the preferred embodiment shown in FIGS. 5 and 6, the connection between plate 27 and external housing 25 is obtained by means of an electromagnetic coupling. To this end, a ferromagnetic element 31 is fixedly connected to the periphery of plate 27 and an electromagnetic track 32 is fastened to the inner wall of housing 25 according to an arrangement parallel to axis A.

(38) When ferromagnetic element 31 faces electromagnetic track 32, an attraction force between elements 31, 32 is generated, such as to oppose possible tangential forces which would make screw 21 rotate.

(39) By deactivating electromagnetic track 32, the magnetic coupling between elements 31, 32 fails and screw 21 is free to be screwed in nut member 19, thereby making the axial upward return action easier.

(40) This is particularly advantageous in case of a failure of the first actuator 11, for instance because of an electromechanical failure or in the absence of power supply, thereby allowing shafts 13, 14 to resume the safety position under the action of resilient means 34.

(41) A rotation decoupling member 37, preventing resilient means 34 from being made to rotate by plate 27 when the magnetic coupling fails, is interposed between resilient means 34 and plate 27.

(42) Once power supply to electromagnetic track 32 ha been restored and the first actuator 11 ha been reactivated, the magnetic coupling between elements 31, 32 is automatically restored as soon as ferromagnetic element 31 is moved to the angular position where the corresponding electromagnetic track 32 is located.

(43) Referring to FIGS. 7 and 8, a third preferred embodiment of an actuation unit 10 is shown, which differs from the first one in that the second shaft 14′ is made of a single axially slidable piece.

(44) The second shaft 14′ is connected to rotation decoupling joint 20 at its upper end portion 30. To this end, upper end portion 30 has a box-shaped configuration which is open upwards in order to allow passage of recirculating ball screw 21, while internally retaining joint 20.

(45) The second shaft 14′ has a portion 14′a on which magnetic rotor 18′ coupled with electromagnetic stator 16 of the second actuator is integrally mounted. Magnetic rotor 18′ has an axial extension greater than the axial extension of stator 16, whereby stator 16 always faces at least partially rotor 18′ independently of the axial position of the latter.

(46) Moreover, two axial guide elements 35, 36 for the second shaft 14′ are provided, which act so that said shaft 14′ is axially guided and can rotate without frictions and losses.

(47) In all embodiments shown, both shaft 13 of the first actuator 11 and shaft 14 of the second actuator 12 are hollow and a rod 26 is slidable inside them to cause ejection of caps, if any, remaining in the gripping means at the end of the capping operation.

(48) The features of the actuation unit for a capping head for the application of caps on containers or bottles as well as of the corresponding capping head according to the present invention are clearly apparent from the above description, as are clearly apparent the relevant advantages.

(49) Further variants of the embodiments described above are possible without departing from the teaching of the invention.

(50) Lastly, it is clear that an actuation unit for a capping head as conceived can undergo several changes and modifications, all included in the invention. Moreover, all details can be replaced by technically equivalent elements. In practice, any material as well as any size can be used, depending on the technical requirements.