Patent Description:
For ease and clearness of description, in the following reference will mainly be made to such ring pull caps, but this should not be understood as a limitation of the scope of protection of the invention.

Ring pull caps are caps having a ring associated with the cap body, said ring allowing easy removal of the cap from the container, typically a bottle, by simply pulling said ring, without having to use appropriate devices. In plants for capping containers by means of such caps, the caps are taken and pulled away by the bottles, the top of each of said bottles engaging with a cap upon passage of said bottle under a dispenser in which the caps are arranged. As a result of the advancement of the bottle, the cap taken from the dispenser is placed onto the mouth of the bottle and the bottle with the cap then advances towards a capping head which clamps the cap onto the neck of the bottle. The same procedure is also applied to other types of caps without ring.

An example of a plant for applying ring pull caps that can be picked from a dispenser is described in Italian Patent <CIT>. Examples of such capping heads for plants of this type are described in patent documents <CIT>, <CIT>, <CIT>, <CIT>, <CIT>.

<CIT> discloses a system for capping containers according to the preamble of claim <NUM> and a method for capping containers according to the preamble of claim <NUM>.

Capping systems with pressing members are known from <CIT> and <CIT>.

In these plants there is the problem that, during travel of the bottle between the dispenser and the capping head, the cap can move away from the mouth of the bottle due to vibrations of the plants or due to gases or foam, in the case of carbonated drinks or foamed drinks, such as beer, thus preventing proper capping. It is thus necessary to adopt measures for holding the cap in the correct position on the bottle until the end of the capping operation. In several known plants, this is achieved by means of a guide plate, which prevents the caps from moving during traveling of the bottle towards the capping head. It is clear that the guide plate must end at the capping zone in order to allow the capping head to perform axial movements necessary for clamping the cap, and therefore there is still some time left during which the cap can experience a movement relative to the bottle.

The object of the invention is to provide a system and a method that guarantee that the caps are held in the correction position until clamping is completed.

According to a first aspect of the invention, there is provided a system for capping containers according to claim <NUM>, by means of ring pull caps that are taken from a dispenser by the containers themselves, wherein a guide plate is provided along the path of the containers between the cap-taking zone and the capping zone, which guide plate is arranged above the containers at a height such that the caps are held on the containers and ends at the capping zone. The guide plate has a longitudinal slot in an end part thereof adjacent to the capping zone, and the capping heads of the system are provided each with a pressing member shaped so as to be able to pass through the slot and associated with elastic control means that push said pressing member towards the cap on a container and keep the cap in contact with the container even beyond the end of the guide plate, until capping is completed.

The pressing member can be mounted inside a hollow guide rod integral for the axial movement with a pushing member intended to cooperate with the pressing member for keeping a cap pressed against the mouth of the container when the capping head has come into contact with the container.

Alternatively, the pressing member can be mounted directly inside the pushing member and be integral thereto for the axial movement.

Advantageously, the longitudinal slot begins slightly before a point in which the axis of a container becomes aligned with the axis of the corresponding capping head and ends at the end of the guide plate, where said longitudinal slot is open.

According to another aspect of the invention, there is provided a method for capping containers according to claim <NUM>, by means of caps that can be taken and pulled away from a dispenser by the containers themselves, in which there is provided a step of guiding the containers, along their traveling between the cap-taking zone and the capping zone, by means of guide plate that is arranged above the containers at a height such that the caps are held on the containers and ends at the capping zone. In the method, the step of guiding the containers is performed by means of guide plate having a longitudinal slot in an end portion thereof adjacent to the capping zone, and there are further provided the following steps:.

These and other features and advantages of the present invention will become apparent from the following description of a preferred embodiment given by way of non-liming example with reference of the annexed Figures, in which:.

Referring to <FIG>, a capping plant has been indicated as a whole with reference numeral <NUM>, said capping plant being intended for applying caps <NUM>, which in the described embodiment as illustrated in the figures are caps with ring 3A to be pulled for opening, to containers <NUM>, especially bottles. As mentioned, the invention, however, is not limited to caps of this type, but it applies also to other types of caps that do not have such ring.

The plant <NUM> comprises, in a conventional manner:.

The capper <NUM> and the inlet and outlet star wheels <NUM>, <NUM> rotate in a mutually synchronous manner, for example in the directions shown by arrows A, B, C in <FIG>.

During rotation of the inlet star wheel <NUM> carrying the bottles <NUM> towards the capper <NUM>, the bottles <NUM> pass by a dispenser or dispensing channel <NUM> containing the caps <NUM> coming from a feeder (not shown) provided on the turret <NUM>, and take and pull away the caps <NUM> by engaging with the inner rim thereof, so that each cap becomes arranged onto the mouth of a respective bottle, onto which it will then by clamped by the corresponding head <NUM>.

Still in a conventional manner, the plant <NUM> further comprises a guide plate <NUM> extending over the bottles <NUM> and being substantially parallel to a platform 11A that carries the bottles <NUM> into the inlet star wheel <NUM>. The vertical position of the guide plate <NUM> must be such as not to hinder advancement of the bottles <NUM>, taking into account that a certain height tolerance is provided for them, while at the same time preventing the caps <NUM> from slipping off the bottles as a result of vibrations of the plant and/or as a result of gases or foam, in the case of carbonated drinks or foamed drinks such as beer and the like. For example, if the height tolerance is in the order of ± <NUM>,<NUM>, the guide plate <NUM> will be arranged about <NUM> above the nominal height of the bottles. The guide plate <NUM> essentially begins at the dispenser <NUM> and ends in the capping zone, in a point such as to allow the capping heads <NUM> to complete their downward axial movement necessary for capping.

Referring also to <FIG>, according to the invention, in order to guarantee that the caps <NUM> are held in position also after the bottles have moved beyond the end of the guide plate <NUM>, said guide plate has, in its end portion adjacent to the capper <NUM>, a longitudinal slot <NUM> open at the end of the guide plate, and the capping heads <NUM> have each a pressing member <NUM> formed so as to be able to pass through the slot <NUM>. The slot <NUM> begins in a region of the guide plate where a capping head <NUM>, during the capping operation, has moved downward essentially to the height of the guide plate (see <FIG>): more particularly, the initial point of the slot <NUM> is preferably located slightly before the point of tangency between the inlet star wheel <NUM> and the turret <NUM>, i.e. the point in which the axis of a bottle <NUM> becomes aligned with the axis of the capping head <NUM> and said head starts moving axially downwards in order to perform capping. The pressing member <NUM> is associated with elastic control means, described below, which hold it in a position of downward thrust, in which its lower portion protrudes from the capping head <NUM>, so that, when the rotation of the turret <NUM> brings the capping head <NUM> to the slot <NUM>, said pressing member passes through said slot and comes into contact with the cap <NUM>, as can be seen in <FIG>. Subsequently, when the capping head <NUM> goes beyond the end of the guide plate <NUM> (see <FIG>), a further downward movement of the capping head <NUM> causes lifting of the pressing member <NUM> upwards, as will be better described in connection with the operation of the system.

Referring to <FIG>, there is shown the structure of the capping head <NUM> in several steps of a capping operation. In particular, the position shown in <FIG> corresponds to the one shown in <FIG>, with the pressing member <NUM> in contact with the cap <NUM> but not biased upwards, and <FIG> shows the capping head <NUM> essentially at the end of its axial travel, in its position where it starts clamping the cap <NUM> onto the bottle <NUM>. <FIG> is an intermediate position between the positions of <FIG> and <FIG>. For the sake of simplicity, the guide plate <NUM> is not shown in said figures.

The capping head <NUM> comprises a substantially cylindrical hollow body <NUM> housing a clamping bell <NUM> mounted in a guide sleeve <NUM>. The assembly bell <NUM> - sleeve <NUM> is kept pressed downwards by a spring <NUM> arranged between the upper face of the sleeve <NUM> and the ceiling of the body <NUM>, and can be moved axially upwards within the body <NUM> against the action of the spring <NUM> during the downward movement of the capping head <NUM>, after the pressing member <NUM> has reached the cap <NUM>. The clamping bell <NUM> advantageously comprises a plurality of arms arranged circumferentially, as described, for example, in document <CIT>, said arms having a lower end portion <NUM> which is flared outwards and intended to cooperate with a cam <NUM> having a complementary shape. In the lower end portion of each arm there is further provided a tooth <NUM> which radially projects inwards and is intended to engage the outer lateral surface of the cap <NUM> in order to deform it and clamp the cap against the bottle <NUM> when the flared portion <NUM> of the clamping bell <NUM>, as a result of the upward movement thereof, engages the cam <NUM>.

Inside the clamping bell <NUM> there is provided an ejector or pushing member <NUM> mounted in a guide sleeve <NUM> and intended to cooperate with the pressing member <NUM> in order to keep the cap <NUM> pressed against the mouth of the bottle <NUM> when the capping head <NUM> has come into contact therewith (<FIG>). To this aim, the ejector <NUM> is axially biased by a spring <NUM> arranged between the inner face of a shoulder <NUM> of the sleeve <NUM> and an annular flange 110A of the outer surface of a hollow rod <NUM>, described below. The ejector <NUM>, too, is kept pressed downwards by the spring <NUM> until the pressing member <NUM> comes into contact with the cap <NUM>, and it can move axially upwards against the action of the spring <NUM> during further downward movement of the capping head <NUM>. The sleeve <NUM> in turn is kept pushed downwards by Belleville spring washers <NUM> arranged between an upper portion, substantially bent inwards at a right angle, of the arms of the clamping bell <NUM> and the upper face of the shoulder <NUM>. As with known capping heads, the Belleville spring washers <NUM>, which have a load higher than that of the spring <NUM>, intervene only in case of irregularities in the shape of the bottle.

The hollow rod <NUM> is attached, for example screwed, inside the ejector <NUM> and in arranged to act as a guide for the pressing member <NUM> housed within its cavity. A longitudinal slot <NUM> formed in the lateral surface of the rod <NUM> acts as a guide for a peg <NUM> of the ejector <NUM>, which peg can be selectively inserted into one of a plurality of holes <NUM> vertically aligned on the lateral surface of the guide sleeve <NUM>. The peg <NUM> has the purpose of preventing the assembly rod <NUM> - ejector <NUM> - pressing member <NUM> to slip off the capping head <NUM> and, by cooperating with the slot <NUM>, limits the travel of the ejector <NUM>. The selection of the hole <NUM> determines the extent by which the ejector <NUM> can protrude downwards from the capping head <NUM>, and thus allows adapting the capping head <NUM> to various heights of the bottles <NUM> to be capped. A helical spring <NUM> arranged inside the cavity of the rod <NUM>, between the ceiling thereof and a shoulder of the outer surface of the pressing member <NUM>, is adapted to keep the pressing member pushed downwards until it comes into contact with the cap <NUM>.

Finally, inside the body <NUM> and around the guide sleeve <NUM> for guiding the clamping bell <NUM>, there is provided a further spring <NUM> intended to remove the load from the clamping bell <NUM> in order to prevent breakage of the bottle <NUM> in the event that the capping head moves downward beyond the nominal height of the mouth of the bottle.

The operation of the system is as follows.

When the coordinated rotational movement of the inlet star wheel <NUM> and the capper <NUM> brings a bottle <NUM> and the capping head <NUM> intended for capping thereof to the slot <NUM> of the guide plate <NUM>, the capping head <NUM> starts moving downwards so that the pressing member <NUM> penetrates through the slot <NUM> and comes into contact with the cap <NUM> (<FIG>, <FIG>). The capping head <NUM>, once it has gone beyond the end of the guide plate <NUM>, can go on moving downwards until it is arranged around the mouth of the bottle <NUM>, and by doing so it causes compression of the spring <NUM> of the pressing member <NUM> until said pressing member by moving upwards becomes flush with the ejector <NUM>. A further downward movement of the capping head <NUM> now causes compression of the spring <NUM> of the ejector until the ejector comes into contact with the guiding surface provided at the mouth of its guide sleeve <NUM>. In this condition, the ejector <NUM> and the guide sleeve <NUM>, too, are essentially in contact with the bottle (<FIG>), and the lower flared portion <NUM> of the clamping bell <NUM> interferes with the cam <NUM> which pushes inwards the arms of the clamping bell, thereby making the teeth <NUM> push laterally against the cap, thus causing deformation thereof and effecting closure (<FIG>). It should be noted that, in the condition of <FIG>, the teeth <NUM> do not push against the cap <NUM> yet, although this cannot be appreciated from the drawing.

It should be noted that, because of the height tolerance for the bottles, the travel of the capping head <NUM> is usually adjusted so as to allow capping also of bottles having a height lower than the nominal height, and it is therefore possible that the head moves further downwards beyond the level required for capping a specific bottle. It is then necessary to prevent the capping head <NUM> from causing the bottles <NUM> to explode or break during such further downward movement: this is achieved by the spring <NUM>, which pushes downwards the assembly clamping bell <NUM> - ejector <NUM> - pressing member <NUM>, thus relieving the load applied by the springs <NUM> - <NUM> - <NUM> - <NUM> and consequently reducing the effort exerted by the head <NUM> on the bottle <NUM>.

It is apparent that the above description has been provided solely by way of nonlimiting example and that variations and modifications are possible without departing from the scope of protection of the invention as defined in the appended claims.

Claim 1:
A system for capping containers (<NUM>) by means of caps (<NUM>) that can be taken and pulled away from a dispenser (<NUM>) by the containers themselves, wherein the containers (<NUM>) with the caps (<NUM>) applied thereon are conveyed from a cap-taking zone to a capping zone where the caps are clamped onto the containers by corresponding capping heads (<NUM>), and wherein, along the path of the containers (<NUM>) between the cap-taking zone and the capping zone, a guide plate (<NUM>) is provided that is located above the containers (<NUM>) at such a height that the caps (<NUM>) are kept on the containers (<NUM>), said guide plate ending at the capping zone in order to allow the capping heads (<NUM>) to perform downward axial movements necessary for capping, wherein said guide plate (<NUM>) has a longitudinal slot (<NUM>) in an end portion thereof adjacent to the capping zone, characterized in that each capping head (<NUM>) is equipped with a pressing member (<NUM>) shaped so as to be able to pass through the slot (<NUM>) and associated with elastic control means (<NUM>) that push said pressing member towards the cap (<NUM>) on a container (<NUM>) through the slot (<NUM>) and keep the pressing member in contact with the cap even beyond the end of the guide plate (<NUM>), until capping is completed.