This invention relates to a machine for the automatic application and tightening of lever-operated bands designed to close the lids of tins or containers such as pails.

It relates in particular to a machine which can use commercial bands, and which is installed on a line along which containers arrive already full and fitted with lids. The machine automatically picks up the bands from a magazine, widens them and fits them onto the edge of the lid, and then tightens them so as to lock the lid closed.

The machine comprises a magazine constituted by one or more substantially horizontal rods from which the bands are hung, and an operating head which moves between a band pick-up position and an insertion position in which it presses the lid onto the container, places the band around the edge and then locks the closing lever, all in accordance with a fully automated cycle.

Many products are sold ready packaged in containers or cans, generally made of metal, which are closed by a removable lid held in position by a metal band which is placed round the edge of the container and the lid and secured by a locking lever.

Machines able to close the band are known according to the state of the art, and one such machine is described, for example, in European patent application number 0618135 in the name of F.A.I.M. Italia.

Said machine comprises means for moving drums along an advancement direction, means for supporting a band to be fitted round the edge of the lid and means for closing the band, consisting of a pin that engages the band closing lever so that said lever rotates and tightens the band.

However, this machine has not proved entirely satisfactory, as it merely tightens the bands, which must have been previously fitted to the edge of the container.

Basically, this machine saves the operator from having to make the effort necessary to close the bands, but requires at least one person to pick up the bands and fit them round the edge of the container, positioning them correctly.

The need is felt in the industry for equipment able to perform all the operations involving picking up, fitting and closing the bands with a fully automated cycle, so that the operator no longer needs to perform these tasks but merely supervises the operation of the machine and fills the magazine with bands when it is empty.

These and other characteristics are achieved with a machine for the automatic application and tightening of pail lid closing bands, which comprises a magazine constituted by one or more substantially horizontal arms from which the bands are hung, an apparatus which feeds the containers to be closed, moving them one at a time to a closing station, and a pick-up and put-down head mounted on a support able to rotate from a position in which the head is aligned on a vertical plane to pick up the bands one at a time to a position in which the head, rotating through 90 degrees, moves to a horizontal plane above the lid, to fit and close the band.

The band closing lever is then engaged by a locking pin which, following a route determined by a cam or the like, engages the lever and causes it to rotate until it is brought to a closing and locking position.

This invention will now be described in detail, by way of example but not of limitation, by reference to the annexed figures wherein:

• figure 1 is a front view of the machine according to the invention;
• figure 2 is a plan view;
• figure 4 is a side view;
• figures 4 and 5 are perspective views of the machine, during the band pick-up stage and the positioning stage on the container respectively;
• figures 6 and 7 are perspective views, from the top and bottom respectively, of the operating head of a machine according to the invention;
• figure 8 is a perspective view of the lever operating devices for closing the band.

With reference to figure 5, the machine according to the invention comprises a base 1, along which containers 2 to be closed are caused to advance by devices of known type, and a structure 3, to which a band supply magazine 4 and a band pick-up and fitting assembly 5 are fitted.

The machine is completed by a band closing system 6.

The containers arrive, already complete with lids, along base 1, which is integral with guides 7 that keep the containers perfectly aligned and move, one at a time, to systems designed for application and clamping of the bands. The bands are picked up from magazine 4, which is substantially constituted by a support 8, rotating around a substantially vertical axis. A pair of orthogonal horizontal rods 9 and 9', from which bands 10 are hung, are connected to said support.

A cylinder 11 (fig. 2) controls the rotation of support 8 through 90 degrees, thus moving one or other of rods 9 carrying the bands alternately to a pick-up area, where the bands are picked up one at a time by a head 12 which is part of assembly 5.

Said assembly comprises a support 13 of a roller guide 14, which slides in relation to support 13 activated by a pneumatic cylinder 15 shown in figure 4.

Head 12 is fitted at the bottom end of roller guide 14.

A pneumatic cylinder 16, hinged on one side to the structure of the machine and on the other to support 13, controls a 90 degree rotation to move roller guide 14, and therefore head 12, from a position in which head 12 is situated on a vertical plane to pick up the bands to a position rotated through 90 degrees in which head 12 is situated on a substantially horizontal plane, parallel to the lids of containers 2, to fit and tighten the band.

Head 12 (figures 6 and 7) comprises a structure integral with roller guide 14, constituted by an upper plate 17 fixed to the slide, and a lower plate 18 rigidly connected to the upper plate; a series of interchangeable shaped segments 19, designed to engage the edge of the lid so as to press it against the container when the closing band is fitted, are mounted on said lower plate. Plate 18 contains a series of slots in which the same number of expander rollers 21, driven by cylinders 22 fitted to plate 18, slide radially.

A second mobile structure consisting of a support ring 23 is fitted to the structure formed by plates 17 and 18; a set of magnets 24 that pick up the bands to be applied to the containers are fitted round the perimeter of said support ring.

A pair of arms 25 or the like, which support a pair of shaped ratchets 26, are also hinged to plate 17; said ratchets help magnets 24 retain the band, and also lock it in place mechanically.

A pair of cylinders 27 control the rotation of arms 25 to move ratchets 26 so that they engage the band.

Ring 23 with magnets 24 and shaped ratchets 26 can traverse axially for a short distance in relation to support plates 17 and 18.

A device constituted by a pair of locking pins 28 is also fitted to said plates; said pins, driven by a cylinder 29, engage the band from the outside to lock it in place while the closing lever is activated to clamp it to the lid.

The clamping is performed by assembly 6, illustrated in detail in figure 8.

Said assembly is constituted by a framework 30 integral with the structure of the machine, on which a support 31 slides; the height of said support can be regulated by adjusting a threaded shaft 32.

A plate 33, containing a shaped slot 34 or a cam or the like, is integral with support 31.

A slide 35 can glide in relation to plate 33 in a first direction, along a guide 36, and a second slide 37 can glide along a guide 38 at right angles to the first slide.

Slide 37 is integral with a post 39, and the movements of the two slides 35 and 37 are controlled by a pneumatic cylinder 40.

The device operates as follows.

At the start of the cycle the head is in the horizontal position, with a band already inserted.

The operator places a set of bands on rods 9 and 9', preferably inserting the rods between the closing lever and the band, so that all the bands align due to the effect of gravity.

When cylinder 11 is activated, the first rod carrying the bands moves to the pick-up zone, while containers already fitted with lids arrive simultaneously, from a filling apparatus, for example.

When the first container reaches the band fitting area, the machine control unit stops its advance in a known way and enables the band fitting cycle, as described below.

The cylinder then causes roller guide 14 to slide downwards until shaped segments 19 engage the edge of the lid.

This operation enables the lid and the container to be perfectly centred on the head, and locks the container by pressing it against the plate and compressing its gasket.

Expulsion cylinders 41, which control the slide of annular support 23 in relation to plates 17 and 18, are then activated.

Annular support 23 with magnets 24 and shaped ratchets 26 then slides downwards until the band is aligned with the edge of the lid, and releases it from expander rollers 21.

The band then closes elastically around the edge of the lid, still held in position by magnets 24 and shaped ratchets 26.

At this point the control unit activates cylinder 29, which closes clamping rollers 28 against the band to hold it in position during closing of the lever. Cylinder 40, which controls the advance of slide 35 along guide 36, is activated at this point. Slide 35 pulls with it slide 37 which, via a pin not illustrated in the figure or other known system, engages shaped slot 34 which guides its movement.

During the first, straight part of its travel, pin 39 engages the band closing lever. In the second part of its travel, the combined movement of the two slides 35 and 37 causes the pin to move along an arc, following the shape of slot 34, and causing the band closing lever to rotate until it goes past the dead centre and perfectly clamps the band to the edge of lid.

The control unit now controls lifting of the head, and cylinder 16 rotates support 13, moving roller guide 14 to a horizontal position and positioning head 12 in a substantially vertical position, in front of the first band to be picked up.

Cylinder 25 is activated to advance the head until the first band is attracted and retained by magnets 24.

Cylinders 27 are now activated to move shaped ratchets 26 so that they engage the band and retain it mechanically; the head is then retracted by cylinder 15, and cylinder 16 is activated to return support 13 to a vertical position, with the head and the corresponding band positioned horizontally, above the next container to be closed.

Simultaneously, cylinders 22 push expander rollers 21 radially outwards; said rollers engage the band from the inside, and open it.

The various devices are now in the starting position, ready to begin a new closing cycle on the next container.

When the set of bands in the magazine has been used up, support 8 of rods 9 is rotated through 90°, moving the second rod, with the bands, to the pick-up area; the operator can then load new bands onto the empty rod.

A machine which automatically fits and tightens the fixing bands of pail lids is therefore provided.

An expert in the field could devise various modifications and variations, all of which should be deemed to fall within the ambit of this invention as defined in the appended claims.