WO2008043489A1

WO2008043489A1 - Cap gripper in capping head of a capping machine

Info

Publication number: WO2008043489A1
Application number: PCT/EP2007/008670
Authority: WO
Inventors: Carlo Corniani
Original assignee: WEIGHTPACK SpA; Weightpack Srl
Current assignee: WEIGHTPACK SpA; Weightpack Srl
Priority date: 2006-10-13
Filing date: 2007-10-05
Publication date: 2008-04-17
Anticipated expiration: 2009-04-13
Also published as: ITMN20060062A1; EP2079657A1

Abstract

A cap gripper in a capping head of a capping machine, comprising a plurality of claws (13-20) which are adapted to come into contact with a cap and are provided with a pivot for articulation on first means, each claw being provided, on the outer surface, with at least one first rolling body (28), which is inserted in a seat which is elongated in the longitudinal direction of the claw and is rigidly coupled to second means, a second rolling body (29) being further provided which is interposed between each claw and the second means and is rigidly coupled to one of the elements and contained within an inclined guide provided in the other element.

Description

CAP GRIPPER IN CAPPING HEAD OF A CAPPING MACHINE Technical Field

The present invention relates to a cap gripper in a capping head of a capping machine. Background Art

It is known that there are capping machines which are adapted to pick up caps from feeder means in order to place each cap at the inlet of an appropriately conveyed container and provide its removable locking by screwing. A very common structure of capping machines provides for the presence of a plurality of capping heads which are associated with a rotating carousel and are provided with means, commonly comprising cams provided on the carousel supporting structure, which are adapted to provide the necessary vertical translational motions to the capping heads, which are also turned by suitable means.

The gripper, particularly for ordinary caps made of plastics, which is provided in known capping heads comprises a centering device which associates snugly with a cap, so that it can convey it; however, since the caps that are progressively manufactured change dimensions due to the wear of the production molds, grip problems arise and are solved by continuous mold maintenance interventions, and therefore with a practice which entails high costs. Disclosure of the Invention

The aim of the present invention is to provide a cap gripper which is capable of working in any case on the caps that are progressively provided, and in particular on short caps made of plastics.

This aim is achieved by a cap gripper in a capping head of a capping machine, according to the invention, characterized in that it comprises a plurality of claws which are adapted to come into contact with the cap and are provided with a pivot for articulation on first means which are actuated so as to provide suitable translational motions in a vertical direction, each claw being provided, at the outer surface, with at least one first rolling body, which is inserted in a seat which is elongated in the longitudinal direction of said claw and is rigidly coupled to second means which are actuated so as to provide appropriate translational motions in a vertical direction and are adapted to be turned, a second rolling body being further provided which is interposed between each claw and said second means and is rigidly coupled to one of said elements and contained within an inclined guide provided in the other of said elements. Brief description of the drawings

Further characteristics and advantages will become better apparent from the description of a preferred but not exclusive embodiment of the invention, illustrated by way of non-limiting example in the accompanying drawings, wherein: Figure 1 is a perspective view of a capping machine;

Figure 2 is a view of a detail of a capping head provided on the machine of Figure 1;

Figure 3 is an enlarged-scale bottom view of the capping head of Figure 2; Figure 4 is a sectional view of the capping head, taken along the line

IV-IV of Figure 3, in the situation in which the claws are open;

Figure 5 is the sectional view of Figure 4, but in the situation in which the claws are closed on a cap;

Figures 6 and 7 are views of two claws; Figure 8 is a view of a detail of another embodiment.

Ways of carrying out the Invention

With reference to the Figures 1 to 7, the reference numeral 1 designates a capping machine comprising a carousel which rotates about a supporting structure 2 and is provided with a plurality of capping heads 3 which are adapted to pick up a cap from feeder means, not shown in the figure, to apply it to the mouth of a container 4.

The capping head 3 comprises first means, which in turn comprise a pusher 5, which is actuated so as to perform suitable translational motions in a vertical direction by a cam 6 provided in the structure 2 and is associated at the lower end with the upper end of a shaft 7; the contact between such ends is ensured, at least in the step for picking up a cap to which the figures relate, by the action of a spring 8 on a hub 9, which is adjustable by actuating a threaded ring 10.

At the lower end, the shaft 7 has an end portion 12 associated therewith, with the interposition of a spring 11, which acts as a shock absorber; such end portion 12 supports, by way of articulation pivots, claws 13, 14, 15, 16, 17, 18, 19, 20, which are designed to come into contact with a cap.

Such claws are absolutely identical, and thus for example the articulation pivot of the claw 15 is constituted by at least one rolling body such as a ball 21, which is snugly inserted in a receptacle provided in the end portion 12 and in receptacle 15a provided in such claw.

Such claw is further provided with a tab 15b, which is designed for contact with a cap. It should be noted that the cam 6 has such a shape as to keep the pusher

5, and accordingly the shaft 7 and the end portion 12, at a constant height during the final steps of the cap gripping operation; this ensures the condition in which the articulation pivots of the claws, constituted by the balls 21 associated with the end portion 12, are likewise at a constant height in the final steps of the pick-up of the cap, and so the closing motion of the claws, which occurs in these steps, is provided in optimum conditions, in any case such as to allow assured grip even when working on short caps.

The capping head 3 also comprises second means, which in turn comprise a perforated rod 22, which is actuated by a cam 23 so as to perform suitable translational motions in a vertical direction and is turned by a controlled electric motor 24; a sleeve 27 is associated with the rod 22, with the interposition of a spring 25 which acts as a shock absorber and acts on a tab 26 connected to the rod 22 by means of a thread 26a, and the sleeve 27 thus follows the rod in its vertical translational motions and is also turned by the rod by way of the traction applied by balls 28a.

For assembly reasons, the sleeve 27 comprises a cylindrical body 27a with which a ring 27c with a closure ring 27d, located at the peripheral region of the set of cap grip claws, is associated stably by way of a connecting ring 27b. Each claw is provided with at least one and preferably two seats which are elongated in the longitudinal direction of the claw and are arranged symmetrically with respect to the central longitudinal plane of the claw, such as 19a, 19b for the claw 19, and the seats accommodate at least two first rolling bodies or balls 28 for the seat 19b which are rigidly coupled to the sleeve 27 by being inserted snugly in seats which are provided partly at the lower end of the cylindrical body 27a and partly within the ring 27c.

Each claw is further provided with a second ball 29 for the claw 15, which is inserted snugly in a seat 19c for the claw 19 and is therefore rigidly coupled to the claw below the articulation pivot 21 for the claw 15; the second ball is contained within a guide 30 for the ball 29 which is provided on the internal surface of the ring 27c and is inclined so as to move away from the axis of the device, passing from the upper end to the lower end.

Finally, the reference numeral 31 designates a circumferential spring which is inserted with continuity in grooves which are provided at the upper end of the claws, such as 15c for the claw 15 and 19d for the claw 19.

Operation of the invention is now described starting from the situation of Figure 4, in which the capping head 3 has moved to the height for picking up a cap and the claws are open around such cap, which is not shown in the figure; the balls 28 are at the upper end of the respective seats and the balls 29 are at the base of the respective guides 30. Upon closing the claws to pick up the cap 32 as shown in Figure 5, and as mentioned earlier, during the closing motion of the claws the articulation pivots 21 of such claws are kept at a constant height.

The sleeve 27 then descends and while the balls 28 merely descend within their respective seats, the guides 30 push the corresponding balls 29 inwardly, thus producing the closure of the claws on the cap, reaching the position of Figure 5; in this situation, the spring 31 is tensioned and, as mentioned, the balls 28 are in an intermediate position of the respective seats. After picking up the cap, the capping head 3, arranges itself, by way of the motion of the carousel, on a container to which such cap will be screwed, and the claws, once capping has ended, are reopened.

The sleeve 27 thus rises, and the contact of the balls 28 with the upper end of the respective elongated seats is capable of producing the reopening of the claws, which is already facilitated in itself by the action of the spring 31.

Figure 8 illustrates the detail of another embodiment of the invention which ensures functional conditions which are identical to those described earlier as regards the closure of the claws. According to such embodiment, each claw 33 is provided with an inclined guide 33a for containing a second ball 34, which is inserted snugly in a seat which is provided within a ring 35 which belongs to the sleeve comprised within the second means and is thus rigidly coupled to said ring.

The described invention is susceptible of numerous other modifications and variations, all of which are within the scope of the appended claims; thus, for example, the second ball of each claw can be arranged above the articulation pivot of such claw, and in this case the containment guide has an inclination which is the opposite of the one described earlier.

The rolling bodies may further be provided in any form, and this applies also to the first and second means actuated by the capping machine and to the articulation pivot of the claws on said first means.

The he disclosures in Italian Patent Application No. MN2006A000062 from which this application claims priority are incorporated herein by reference.

Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

1. A cap gripper in a capping head of a capping machine, characterized in that it comprises a plurality of claws which are adapted to come into contact with a cap and are provided with a pivot for articulation on first means which are actuated so as to provide suitable translational motions in a vertical direction, each claw being provided, at the outer surface, with at least one first rolling body, which is inserted in a seat which is elongated in the longitudinal direction of said claw and is rigidly coupled to second means which are actuated so as to provide appropriate translational motions in a vertical direction and are adapted to be turned, a second rolling body being further provided which is interposed between each claw and said second means and is rigidly coupled to one of said elements and contained within an inclined guide provided in the other of said elements.

2. The gripper according to claim 1, characterized in that said second rolling body is rigidly coupled to each claw by being inserted snugly in a seat defined in said claw, and is contained within an inclined guide which is provided within said second means.

3. The gripper according to claim 1, characterized in that said second rolling body is contained within an inclined guide which is provided within each claw, and is rigidly coupled to said second means by being inserted snugly in a seat which is defined on said second means.

4. The gripper according to claims 1 and 2, characterized in that said second rolling body is rigidly coupled to each claw by being inserted snugly in a seat which is provided on said claw below the articulation pivot on the first means, and is contained within a guide which is defined in said second means and is inclined so as to move away from the axis of the gripper, passing from the upper end to the lower end.

5. The gripper according to claims 1 and 3, characterized in that said second rolling body is contained within a guide which is defined in each claw below the articulation pivot on the first means and is inclined so as to move away from the axis of the gripper in going from the upper end to the lower end, and is rigidly coupled to said second means by being inserted snugly within a seat defined on said second means.

6. The gripper according to one or more of the preceding claims, characterized in that the articulation pivot of each claw on said first means is provided by means of a ball.

7. The gripper according to one or more of the preceding claims, characterized in that each claw is provided with two first rolling bodies, which are inserted within respective seats which are elongated in the longitudinal direction of said claw and are arranged symmetrically with respect to the central longitudinal plane of the claw.

8. The gripper according to one or more of the preceding claims, characterized in that the rolling bodies are provided by means of balls.

9. The gripper according to one or more of the preceding claims, characterized by the presence of circumferential elastic means which are inserted with continuity in grooves provided proximate to the upper end of each claw.

10. The gripper according to one or more of the preceding claims, characterized in that said first means actuated to provide appropriate translational motions in a vertical direction are adapted to remain at a constant height during the final steps of the operation for picking up the cap.

11. The gripper according to one or more of the preceding claims, characterized in that said first means comprise a pusher which is actuated by a cam provided within the structure of the capping machine and is associated with a shaft which is maintained by the action of a spring in contact at the upper end with said pusher and is provided with an end portion which supports the articulation pivots of each claw and is associated with said shaft by way of the interposition of a spring proximate to the lower end.

12. The gripper according to one or more of the preceding claims, characterized in that said second means comprise a rod which is perforated in order to allow the passage of the pusher comprised within the first means and is actuated by a cam which is provided within the structure of the capping machine, said rod being associated with the interposition of a spring with the sleeve located in its lower portion at the peripheral region of the set of claws, so as to interact by means of rolling bodies with said claws.