Capping head for the application of caps on containers or bottles

Abstract

A capping head for the application of caps on containers or bottles, as well as a capping assembly, are provided. The capping head comprises a hollow housing internally defining at least a first chamber in which a shaft rotating about a longitudinal axis is housed, the rotating shaft being coupled with the hollow housing through the interposition of a magnetic or electromagnetic decoupling assembly comprising at least a rotor and a stator. The decoupling assembly being suitable to allow a relative rotation between the hollow housing and the rotating shaft when the rotating shaft is subjected to a braking torque exceeding a threshold torque. Means for enhancing the thermal dissipation power generated by the decoupling assembly is located inside the hollow housing.

Claims

1. A capping head (10) for the application of caps on containers or bottles, comprising a hollow housing (11) internally defining at least a first chamber (19) in which a shaft (13) rotating about a longitudinal axis (A) is housed, the rotating shaft (13) being coupled with the hollow housing (11) through the interposition of a magnetic or electromagnetic decoupling assembly (20) configured to generate thermal dissipation power and comprising at least a rotor (21) and a stator (22), the magnetic or electromagnetic decoupling assembly (20) being suitable to allow a relative rotation between the hollow housing (11) and the rotating shaft (13) when the rotating shaft (13) is subjected to a braking torque exceeding a threshold torque, wherein inside the hollow housing (11) there are means for enhancing the thermal dissipation power, said means comprising elements (28a, 29a, 26, 17a, 17b) which are different from the rotor (21) and the stator (22) and on which eddy currents flow, wherein said elements (28a, 29a, 26, 17a, 17b) which are different from the rotor (21) and the stator (22) and on which eddy currents flow comprise at least one out of: at least one coating layer (29a) of an outer surface portion (29) of the stator (22) radially facing the rotor (21); and/or at least one coating layer (28a) of an outer surface portion (28) of the rotor (21) radially facing the stator (22); and/or at least one axial extension element (26) of the stator (22) of the magnetic or electromagnetic decoupling assembly (20); and/or at least one annular element (17a, 17b) placed at the rotor (21) of the magnetic or electromagnetic decoupling assembly (20) in such a way as to define an axial extension of the same rotor (21) and located around the rotating shaft (13), said at least one annular element (17a, 17b) having such radial size that it does not prevent stator (22) from sliding between a position of maximum overlap and a position of minimum overlap with rotor (21).

2. The capping head (10) according to claim 1, wherein: said at least one coating layer (29a) of the outer surface portion (29) of the stator (22) radially facing the rotor (21) is made of a material having a resistivity lower than or equal to 0.5 Ω*mm.sup.2/m; and/or said at least one coating layer (28a) of the outer surface portion (28) of the rotor (21) radially facing the stator (22) is made of a material having a resistivity lower than or equal to 0.5 Ω*mm.sup.2/m; and/or said at least one axial extension element (26) of the stator (22) of the magnetic or electromagnetic decoupling assembly (20) is at least partially made of a material having a resistivity lower than or equal to 0.5 Ω*mm.sup.2/m; and/or said at least one annular element (17a, 17b) is at least partially made of a material having a resistivity lower than or equal to 0.5 Ω*mm.sup.2/m.

3. The capping head (10) according to claim 2, wherein the material of which are made the at least one coating layer (29a) of the outer surface portion (29) of the stator (22) and/or the at least one coating layer (28a) of the outer surface portion (28) of the rotor (21), and/or at least part of the at least one axial extension element (26) of the stator (22) and/or at least part of the at least one axial extension annular element (17a, 17b) of the rotor (21) is any one or more of the materials belonging to the group consisting of: aluminum; silver; copper; gold; ferrites; metal alloys; metal alloys with rare earth elements.

4. The capping head (10) according to claim 3, wherein the at least one coating layer (29a) of the outer surface portion (29) of the stator (22) and/or the at least one coating layer (28a) of the outer surface portion (28) of the rotor (21), and/or at least an outer surface portion of the at least one axial extension element (26) of the stator (22) and/or at least an outer surface portion of the at least one axial extension annular element (17a, 17b) of the rotor (21) comprise at least one sectioning notch.

5. The capping head (10) according to claim 4, wherein the axial extension element (26) of the stator (22) comprises a finning (27) radially projecting from at least an outer surface portion opposed to an outer surface radially facing the rotor (21).

6. The capping head (10) according to claim 5, wherein the means for enhancing the thermal dissipation power generated by the magnetic or electromagnetic decoupling assembly (20) comprises at least one screen made of a thermally insulating material (46) at least partially coating at least a portion of an inner wall of the hollow housing (11).

7. The capping head (10) according to claim 3, wherein the axial extension element (26) of the stator (22) comprises a finning (27) radially projecting from at least an outer surface portion opposed to an outer surface radially facing the rotor (21).

8. The capping head (10) according to claim 3, wherein the hollow housing (11) internally defines a second chamber (40) arranged adjacent to the first inner chamber (19) in axial direction (A), at least one spring (41) for compensating an axial force being housed in the second inner chamber (40), wherein a plate (42) movable in axial direction in order to perform an adjustment of the preloading tension of the at least one compensation spring (41) is arranged between the first (19) and the second (40) inner chamber, the rotating shaft (13) being hollow to allow the access to the adjustment plate (42).

9. The capping head (10) according to claim 2, wherein the at least one coating layer (29a) of the outer surface portion (29) of the stator (22) and/or the at least one coating layer (28a) of the outer surface portion (28) of the rotor (21), and/or at least an outer surface portion of the at least one axial extension element (26) of the stator (22) and/or at least an outer surface portion of the at least one axial extension annular element (17a, 17b) of the rotor (21) comprise at least one sectioning notch.

10. The capping head (10) according to claim 9, wherein the axial extension element (26) of the stator (22) comprises a finning (27) radially projecting from at least an outer surface portion opposed to an outer surface radially facing the rotor (21).

11. The capping head (10) according to claim 9, wherein the hollow housing (11) internally defines a second chamber (40) arranged adjacent to the first inner chamber (19) in axial direction (A), at least one spring (41) for compensating an axial force being housed in the second inner chamber (40), wherein a plate (42) movable in axial direction in order to perform an adjustment of the preloading tension of the at least one compensation spring (41) is arranged between the first (19) and the second (40) inner chamber, the rotating shaft (13) being hollow to allow the access to the adjustment plate (42).

12. The capping head (10) according to claim 2, wherein the axial extension element (26) of the stator (22) comprises a finning (27) radially projecting from at least an outer surface portion opposed to an outer surface radially facing the rotor (21).

13. The capping head (10) according to claim 12, wherein the hollow housing (11) internally defines a second chamber (40) arranged adjacent to the first inner chamber (19) in axial direction (A), at least one spring (41) for compensating an axial force being housed in the second inner chamber (40), wherein a plate (42) movable in axial direction in order to perform an adjustment of the preloading tension of the at least one compensation spring (41) is arranged between the first (19) and the second (40) inner chamber, the rotating shaft (13) being hollow to allow the access to the adjustment plate (42).

14. The capping head (10) according to claim 2, wherein the hollow housing (11) internally defines a second chamber (40) arranged adjacent to the first inner chamber (19) in axial direction (A), at least one spring (41) for compensating an axial force being housed in the second inner chamber (40), wherein a plate (42) movable in axial direction in order to perform an adjustment of the preloading tension of the at least one compensation spring (41) is arranged between the first (19) and the second (40) inner chamber, the rotating shaft (13) being hollow to allow the access to the adjustment plate (42).

15. The capping head (10) according to claim 1, wherein the hollow housing (11) internally defines a second chamber (40) arranged adjacent to the first inner chamber (19) in axial direction (A), at least one spring (41) for compensating an axial force being housed in the second inner chamber (40), wherein a plate (42) movable in axial direction in order to perform an adjustment of the preloading tension of the at least one compensation spring (41) is arranged between the first (19) and the second (40) inner chamber, the rotating shaft (13) being hollow to allow the access to the adjustment plate (42).

16. The capping head (10) according to claim 15, wherein the adjustment plate (42) comprises a threaded peripheral surface (42a) coupled with a threaded circular opening (44) interposed between the first (19) and the second (40) inner chamber, the threaded peripheral surface (42a) of the adjustment plate (42) comprising a plurality of axial longitudinal slots (43), preferably arranged at regular angular intervals.

17. The capping head (10) according to claim 15, wherein a plurality of pressing members (45) radially project from the periphery of the circular opening (44), which members (45) are suitable to engage with the longitudinal slots (43) of the adjustment plate (42) when the longitudinal slots (43) are at angular positions corresponding to the angular positions of the pressing members (45).

18. The capping head (10) according to claim 1, wherein the rotor (21) and the stator (22) of the magnetic decoupling assembly (20) comprise a magnetic rotor (21) shaped as a first hollow cylindrical element and a magnetic stator (22) shaped as a second hollow cylindrical element placed radially more outwards with respect to the first hollow cylindrical element (21), the stator (22) being connected to the hollow housing (11) in a rotationally fixed manner, but so as to be axially translatable between the maximum overlap position and the minimum overlap position with the rotor (21), the rotor (21) being connected to the rotating shaft in a rotationally fixed manner.

19. A capping assembly comprising a movable support structure for moving at least one capping head (10) for the application of caps on containers or bottles according to claim 1 along a conveying path of containers to be capped.

20. The capping head (10) according to claim 1, wherein the means for enhancing the thermal dissipation power generated by the magnetic or electromagnetic decoupling assembly (20) comprises at least one screen made of a thermally insulating material (46) at least partially coating at least a portion of an inner wall of the hollow housing (11).

21. The capping head (10) according to claim 1, wherein: said at least one coating layer (29a) of the outer surface portion (29) of the stator (22) radially facing the rotor (21) is made of a material having a resistivity lower than or equal to 0.1 Ω*mm.sup.2/m; and/or said at least one coating layer (28a) of the outer surface portion (28) of the rotor (21) radially facing the stator (22) is made of a material having a resistivity lower than or equal to 0.1 Ω*mm.sup.2/m; and/or said at least one axial extension element (26) of the stator (22) of the magnetic or electromagnetic decoupling assembly (20) is at least partially made of a material having a resistivity lower than or equal to 0.1 Ω*mm.sup.2/m; and/or said at least one annular element (17a, 17b) is at least partially made of a material having a resistivity lower than or equal to 0.1 Ω*mm.sup.2/m.

22. The capping head (10) according to claim 1, wherein: said at least one coating layer (29a) of the outer surface portion (29) of the stator (22) radially facing the rotor (21) is made of a material having a resistivity lower than or equal to 0.05 Ω*mm.sup.2/m; and/or said at least one coating layer (28a) of the outer surface portion (28) of the rotor (21) radially facing the stator (22) is made of a material having a resistivity lower than or equal to 0.05 Ω*mm.sup.2/m; and/or said at least one axial extension element (26) of the stator (22) of the magnetic or electromagnetic decoupling assembly (20) is at least partially made of a material having a resistivity lower than or equal to 0.05 Ω*mm.sup.2/m; and/or said at least one annular element (17a, 17b) is at least partially made of a material having a resistivity lower than or equal to 0.05 Ω*mm.sup.2/m.

Description

(1) In the drawings:

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

(3) FIG. 2 is a sectional view of the capping head shown in FIG. 1;

(4) FIG. 3a is a sectional view of the rotor—stator assembly of the capping head shown in FIG. 1 with a single annular magnetic element placed above the rotor:

(5) FIGS. 3b and 3c are axonometric views of the rotor—stator assembly shown in FIG. 3a;

(6) FIGS. 4a to 4c are partial axonometric views of the rotor—stator assembly of the capping head shown in FIG. 1 in three different axial overlap configurations;

(7) FIG. 5 is a part sectional view of the capping head shown in FIG. 1 with a tool for adjusting the axial load spring inserted therein;

(8) FIG. 6 is an axonometric view of the disc for adjusting the axial load spring of the capping head shown in FIG. 1.

(9) 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.

(10) Referring to FIG. 1, there is shown a preferred embodiment of 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.

(11) Capping head 10 includes a hollow housing 11, provided at its upper side with an interface 12 for coupling with a spindle (not shown) suitable to impart a rotary movement about a longitudinal axis A and/or a translatory movement along that axis.

(12) A rotating shaft 13 carried by hollow housing 11 by means of a pair of rolling bearings 14 is housed within a first chamber 19 defined inside hollow housing 11.

(13) Rotating shaft 13 includes at its lower side an interface 15 for connection to a member (not shown) for gripping a cap.

(14) A magnetic rotor 21, shaped as a first hollow cylindrical element, is mounted on rotating shaft 13 and forms, together with a stator 22 shaped as a second hollow cylindrical element placed radially more outwards with respect to the first element 21, a magnetic decoupling assembly or a magnetic clutch 20.

(15) Magnetic rotor 21 consists of a plurality of permanent magnets 21a arranged along its annular extension with alternating polarities.

(16) In the embodiment illustrated, stator 22 is made of a ferromagnetic material subjected to hysteresis. In the alternative, stator 22 may comprise a plurality of permanent magnets 22a arranged with alternating polarities along its annular extension.

(17) Stator 22 is connected to hollow housing 11 in a rotationally fixed manner, whereas the axial position of stator 22 inside hollow housing 11 is adjustable in order to set the surface portion over which rotor 21 and stator 22 overlap.

(18) To this end, in the embodiment illustrated, stator 22 is connected to an external covering 23 including a plurality of rolling seats 24 formed on the outer skirt of covering 23. A ball 25 engages in a freely rotatable manner with each of two diametrically opposite seats 24. Moreover, hollow housing 11 is externally coated by an annular ferrule 20 having a helical track 31 on its inner wall. Balls 25 pass through longitudinal slots 16 extending parallel to axis A and formed in the wall of hollow housing 11, and engage also with helical track 31. Slots 16 act as longitudinal guides for balls 25.

(19) Therefore, a rotation of annular ferrule 30 makes balls 25 slide along helical rack 31 and inside slots 16. Consequently, a translatory movement of stator 22 relative to hollow housing 11 occurs, parallel to longitudinal axis A. It is therefore possible to set the surface portion over which rotor 21 and stator 22 overlap. More specifically, stator 22 is movable between a position of maximum overlap with rotor 21, shown in FIG. 4a, and a minimum overlap position, shown in FIG. 4b, since it is slidable along a direction parallel to axis A.

(20) According to the present invention, external covering 23 of stator 22 includes an axial extension portion 26, made as a skirt, axially extending with respect to covering 23 of stator 22. More particularly, skirt-shaped extension 26 extends in opposite direction with respect to the sliding direction allowed to stator 22 when it moves from the position of maximum overlap with rotor 21 to the minimum overlap position. In this way, when the stator is in the minimum overlap position, skirt-shaped extension 26 faces rotor 21, as shown in FIG. 4c.

(21) Skirt-shaped extension 26 has, on its radially external surface, a finning 27 that, by generating turbulence, increases the convection effect, thereby obtaining a quicker dissipation and distribution of the heat generated in skirt-shaped extension 26 because of the rotation of the magnetic field generated by rotor 22, when said extension faces the same rotor 22.

(22) Above rotor 21 two annular elements 17a, 17b are housed, which are coated with a material having a resistivity lower than 0.5 Ω*mm.sup.2/m, are located around rotating shaft 13 and have such radial sizes that they do not prevent stator 22 from sliding between the position of maximum overlap and the position of minimum overlap with rotor 21.

(23) Surface 28 of rotor 21 radially facing stator 22 and surface 29 of stator 22 radially facing rotor 21 are each coated with a layer 28a, 29a of a low resistivity material in order to make generation of eddy currents easier. More specifically, in the embodiment illustrated, coating layers 28a, 29a are made of silver that, besides having a resistivity of 0.016 Ω*mm.sup.2/m, additionally offers antibacterial properties.

(24) Moreover, mutually facing surfaces 28, 29 of rotor 21 and stator 22 have notches (not shown), obtained by trimming, determining a lengthening of the electrical paths, thereby further increasing the eddy currents.

(25) Hollow housing 11 internally defines a second chamber 40 arranged axially adjacent to the first inner chamber 19, at the end of rotating shaft 13 opposed to connection interface 15.

(26) A compensation spring 41 for a controlled transmission of the longitudinal force imparted by the spindle is housed in the second chamber 40.

(27) The first chamber 19 of the hollow housing and the second chamber 40 are separated by means of a plate 42, shown in FIG. 6, for adjusting the preloading tension of compensation spring 41. For preloading adjustment, plate 42 can be made to rotate by means of a tool 42 (shown in FIG. 5) that can be introduced through rotating shaft 13, which to this end is hollow.

(28) Peripheral surface 42a of adjustment plate 42 is threaded and has a plurality of vertical longitudinal slots 43 arranged at regular intervals.

(29) Adjustment plate 42 engages with a threaded circular opening 44 separating chambers 19, 40. A plurality of ball-shaped pressing members 45 project from circular opening 44 and engage with vertical slots 43 when the latter are in angular positions facing pressing members 45.

(30) In this manner, a stable screwing position of adjustment plate 42 is defined, thereby preventing a back movement thereof.

(31) Starting from a stable position, plate 42 can again be made to rotate by applying a torsion imparted by means of tool 100, and thus it can be brought to a different (previous or subsequent) stable position. In this manner, a gradual adjustment of the compression of spring 41 to a new level is obtained.

(32) The peripheral wall of the second inner chamber 40 of external housing 11 is coated with a screen 46 of a thermally insulating material.

(33) The operation of capping head 10 for the application of caps on containers or bottles according to the invention is as follows.

(34) When magnetic decoupling assembly 20 is in the configuration of maximum overlap between mutually facing surfaces 28, 29 of stator 22 and rotor 21 (shown in FIG. 4a), coating layers 28a, 29a of such surfaces 28, 29, having a low resistivity and provided with sectioning notches, cause generation of a high amount of surface eddy currents, which consequently give rise to the generation of a sufficient dissipation thermal power to attain pasteurisation and/or sterilisation temperatures, as the cases may be.

(35) When magnetic decoupling assembly 20 is in the configuration of intermediate overlap between mutually facing surfaces 28, 29 of rotor 21 and stator 22 (shown in FIG. 4b), a portion of surface 28 of rotor 21 overlaps axial extension portion 26 of stator 22 and a portion of surface 29 of stator 22 overlaps at least one annular element 17a placed on the upper side of rotor 21.

(36) The reduced generation of dissipation thermal power due to the only partial overlap of surfaces 28, 29 is compensated by the eddy currents generated on the surfaces of axial extension portion 26 of stator 22 and of annular element 17a placed on the upper side of rotor 21.

(37) Actually, axial extension portion 26 of stator 22 facing rotor 21 is subjected to rotating magnetic fields generated by rotor 21, which induce the generation of surface currents in the conductive material of which such extension 26 is made. Moreover, finning 27 provided on that extension portion 26 causes, during rotation, a higher heat exchange towards the inside of the head, thereby determining a quicker and more uniform distribution of the heat generated.

(38) Similarly, also stator 22 is capable of inducing the generation of eddy currents on the outer surface of annular element 17a placed above rotor 21.

(39) Thus, both elements 26, 17a contribute to enhance the dissipation thermal power generated by magnetic decoupling assembly 20.

(40) Lastly, when magnetic decoupling assembly 20 is in the configuration of minimum overlap between mutually facing surfaces 28, 29 of rotor 21 and stator 22 (shown in FIG. 4c), surface 29 of stator 22 overlaps both annular elements 17a, 17b placed on the upper side of rotor 21, whereas a portion of surface 28 of rotor 21 overlaps axial extension element 26 of stator 22.

(41) Due to the same phenomena as disclosed with reference to FIG. 4b, axial extension element 26 and annular elements 17a, 17b contribute to enhance the dissipation thermal power generated by magnetic decoupling assembly 20, thereby compensating the lower generation of dissipation thermal power due to the even smaller overlap between surfaces 28, 29 of rotor 21 and stator 22.

(42) Moreover, the thermally insulating screen ensures that the thermal power generated inside the capping head is not dissipated towards the outside, thereby allowing in this case that also the second inner chamber 40 attains the sterilisation temperatures.

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

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

(45) It is clear moreover that a capping head for the application of caps on containers or bottles as conceived is susceptible of several changes and modifications, all lying within the scope of the invention. Moreover all details can be replaced by technically equivalent elements. In the practice, any material, as well any size, can be employed depending on the technical requirements.