Patent Application
20120011809
This application claims benefit of Italian patent application serial number TO2010A000606, filed Jul. 13, 2010, which is herein incorporated by reference.
1. Field of the Invention
The present invention relates to a head for applying threaded caps on containers that are to be used in automatic machines for closing containers.
More precisely, the invention regards a head comprising a tubular bushing, a shaft that extends coaxially within the tubular bushing and that carries at a bottom end thereof an attachment for a cap gripping member, and a magnetic clutch set between the tubular bushing and the shaft.
2. Description of the Related Art
Heads for applying threaded caps are known in which an adjustment ring-nut is provided set on the outside of the tubular bushing, in which the rotation of said ring-nut with respect to the tubular bushing enables variation of the distance in an axial direction between two mutually facing magnetic disks, which constitute a magnetic clutch that limits the maximum torque transmissible between the tubular bushing and the shaft carrying the cap gripping member.
In many technical fields, it is necessary to ensure that the application of caps to containers takes place in an aseptic environment. In these cases, it is necessary for the heads for application of the caps to be washable. To meet this requirement, it is necessary for the magnetic clutch to be isolated in a liquid-tight way from the external environment. It is moreover necessary to ensure that the adjustment of the torque transmissible by the magnetic clutch can be performed without exposing potentially contaminated areas.
The object of the present invention is to provide a head for applying caps that will enable the aforesaid requirements to be met.
According to the present invention, said object is achieved by a head for applying caps having the characteristics forming the subject of Claim 1.
A further object of the present invention is to provide a head for applying threaded caps that will enable replacement in a simple and fast way of the springs that press elastically in an axial direction on the supporting bushing so as to change the axial force with which the caps are pressed on the containers.
According to the present invention, said purpose is achieved by a head having the characteristics forming the subject of Claims 7 and 8.
The characteristics and advantages of the head according to the present invention will emerge clearly in the course of the ensuing detailed description, which is provided purely by way of non-limiting example, with reference to the attached drawings, in which:
With reference to
The head 10 comprises a top body 12 having a threaded hole 14, by means of which the top body 12 is directly fixed to the bottom end of a spindle 16 that is able to turn about a longitudinal axis A.
In the sequel of the description and in the claims the terms “top” and “bottom” refer to the normal position of use of the head 10, in which the longitudinal axis A is vertical.
The spindle 16 forms part of an automatic machine for applying threaded caps on containers. In operation, the spindle 16 is actuated with a movement of rotation about the longitudinal axis A and with a simultaneous movement of translation along said longitudinal axis A. The movements of rotation and translation are co-ordinated with respect to one another so as to obtain a helical movement of the spindle 16. The way in which the movement of roto-translation of the spindle 16 is generated can be considered conventional and lies outside the scope of the present invention.
The head 10 comprises an intermediate support 18, which is rotationally fixed with respect to the top body 12 and is mobile with respect to the top body 12 in the direction of the longitudinal axis A. The intermediate support 18 is connected to the top body by means of a plurality of guide columns 20 (only one of which is visible in
A plurality of helical compression springs 32 pushes elastically the intermediate support 18 downwards towards the position of maximum relative distance between the top body 12 and the intermediate support 18.
Each helical spring 32 has its opposite ends engaged on respective short pins 34, 36, aligned with respect to one another and projecting in opposite directions respectively from the top body 12 and the intermediate support 18. The helical springs 32 push the intermediate support 18 towards the position of maximum distance from the top body 12. When the supporting body 18 is subjected to a force directed upwards, the springs 32 are compressed and allow a movement of approach of the intermediate support 18 with respect to the top body 12 in the direction of the axis A.
The pins 34, 36 that engage the ends of the springs 32 have a limited extension in the axial direction. The free gap between the pins 34, 36, with the top body 12 and the intermediate support 18 at the maximum relative distance, is greater than the length of the spring 32 in the compressed position. Thanks to this, it is possible to carry out conveniently replacement of the springs 32 with springs having a different stiffness without having to dismantle the head 10. In order to replace the springs 32 a pair of pliers designated by 38 in
With reference to
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With reference to
The through openings 70 are elongated in a longitudinal direction and function as a guide for the radial projections 68. The radial projections 68 are constrained in a rotational direction with respect to the through openings 70 and are free to move in a longitudinal direction with respect to the through openings 70. Consequently, the magnet support 64 and the bottom magnet 56 fixed thereto are rotationally fixed with respect to the tubular bushing 40 and are free to perform a movement of adjustment with respect to the tubular bushing 40 in the direction of the longitudinal axis A.
The head 10 comprises an adjustment ring 72 set on the outside of the tubular bushing 40. The adjustment ring 72 is constrained axially with respect to the tubular bushing 40 and is able to turn about the longitudinal axis A. The adjustment ring 72 has an internal thread 74 that engages the external thread 69 of the radial projections 68.
A lid 76 is screwed in an internal thread 78 of the tubular bushing 40. The lid 76 constrains the adjustment ring 72 axially with respect to the tubular bushing 40. The adjustment ring 72 rests axially on the lid 76 via a spacer ring 80. The top end of the adjustment ring 72 rests against an outer edge of the tubular bushing 40. It will be understood that with this arrangement the adjustment ring 72 is free to turn about the axis A but is axially constrained with respect to the tubular bushing 40.
The rotation of the adjustment ring 72 about the axis A causes, via coupling of the threads 69, 74, a movement in an axial direction of the magnet support 64 and of the bottom magnet 56 fixed thereto. Said movement enables adjustment of the axial distance between the magnets 54, 56 and, consequently, the maximum torque transmitted by means of the magnetic clutch 52 from the tubular bushing 40 to the shaft 42.
With reference to
The top end of the adjustment ring 72 is inserted within an annular edge 82 of the intermediate support 18. A first sealing element 84 is set between the annular edge 82 and the adjustment ring-nut 72. A second sealing element 86 is set between a bottom end of the adjustment ring 72 and the lid 76. A third sealing element 88 is set between the lid 76 and the shaft 42. There may also be provided a fourth sealing element 90, set between the ring 80 and the lid 76. The first, second, and fourth sealing elements are preferably constituted by an O-ring, and the third sealing element is preferably constituted by a lip seal.
The arrangement illustrated enables isolation, in a liquid-tight way, from the external environment, of the part of the head 10 that contains the magnetic clutch 52 and the bearings 48, 50.
This characteristic of impermeability, which is improved as compared to the known solutions, is particularly appreciated in the packaging sector, especially in an aseptic environment. The clutch assembly, in addition to guaranteeing tightness in regard to jets of liquids (from outside inwards, and vice versa) is extremely compact and clean. Hygiene is guaranteed by the fact that in order to regulate the torque it is not necessary to raise or displace pieces (thus exposing potentially dirty parts) but it is sufficient to turn the ring-nut 72 manually. The O-rings 80, 86 are mounted in open seats and are hence readily washable.
The top body 12, the intermediate support 18, and the guide columns 20 are designed so as to ensure a high level of hygiene, for example by providing vertical draining grooves in the guide columns 20, inclined surfaces of the top body 12 and of the intermediate support 18 and drain channels in the pins 34 where the springs 32 are anchored. The fast replacement of the springs, a feature that is particularly appreciated by customers, does not require dismantling of any item but simple vertical compression using a special pair of pliers operated manually.
Of course, without prejudice to the principle of the invention, the details of construction and the embodiments may vary widely with respect to what has been described and illustrated herein, without thereby departing from the scope of the present invention, as defined by the ensuing claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| TO2010A000606 | Jul 2010 | IT | national |
