Background art A straight chamber capping machine is described in US Patent 4,279,115, in which the containers move forward, as shown in detail in figure 10 thereof, carried by an endless conveyor, laterally restrained by a pair of restraint chains, provided with pads or shoes made from rubber or plastic, which press the containers sideways while they move beneath the closure means, that apply the caps. In such a manner, the swinging of the containers with respect of the conveyor belt is avoided and the operating speed of the machine can be increased.

However, the capping machines of the kind described in US Patent 4,279,115, although they have become rather common, suffer from the drawback that, when the plastic or rubber pads must be replaced because they are worn or damaged, generally speaking, the whole chain must be removed in order to proceed, at the repair shop instead of on the field, with the detachment of the worn pads and the vulcanisation of the new pads on the supporting links.

Disclosure of the invention Accordingly, the main object of the present invention is to provide means that make the maintenance of the restraint chains simpler and easier, and consequently cheaper, in particular as far as the straight chamber capping

machines are concerned.

Another object of the present invention is to provide a restraint chain comprising improved pad supporting links, having a simple and cheap structure, useful for a mass production.

According to the present invention, a pad supporting link for restraint chains is characterised in that it comprises in combination a pad contacting wall and two flanges, extending from the wall, the arrangement being such that the pad, intended for pressing the item to be restrained, is received and fastened by disengageable mechanical fit into the recess delimited by said wall and said flanges.

The main advantage obtained with the chain link according to the present invention consists in that the sworn pad can be removed from its housing without any particular tool and can be easily replaced with a new spare pad, on the machine workplace without the need of removing the whole restraint chain.

Brief description of drawings The present invention will be further clarified herein below and other advantages will be highlighted by the description of two practical embodiments of the pad supporting link for restraint chains according to the present invention, this description being given by way of example on a purely illustrative and non-limiting basis, with reference to accompanying drawings, in which: Figure 1 is a top plan view and shows a section of a restraint chain provided with pad supporting links according to a first embodiment of the present invention; Figure 2 is cross sectional view taken along line II- II of figure 1; Figure 3a is a top plan view and shows a pad supporting link for restraint chains according to the present invention; Figure 3b is a cross sectional view taken along line IIIb-IIIb of figure 3a;

Figure 3c is a plan sectional view taken along line IIIc-IIIc of figure 3b; Figure 3d is a side elevation view of the pad supporting link of the figure 3a; Figure 4a is a top plan view and shows a pad to be inserted into the pad supporting link of figure 3a; Figure 4b is a cross sectional view taken along line IVb-IVb of figure 4a; Figure 4c is a side elevation view of the pad of the figure 4a; Figure 5 is a top plan view similar to figure 1 and shows a second embodiment of a pad supporting link according to the present invention; and Figure 6 is a cross sectional view taken along line VI - VI of figure 5.

Best mode for carrying out the invention With reference to the enclosed drawings, first of all let us say that here the cross and longitudinal directions always refer to the container motion path on the capping machine, whereas the horizontal and vertical planes refer to the horizontal plane defined by the conveyor belt on which the containers are supported.

With reference now in particular to figure 1 of the accompanying drawings, it is seen that, according to the present invention, a restraint chain comprises a number of outer chain links 10, having pad supporting means, which alternate with a same number of inner chain links 12, the latter links being of a usual construction.

As it is better shown in figure 2, and besides, as it is usual in the field of the gearing chains, each outer link 10 is connected to the adjacent inner link 12 by a pin 14.

According to the present invention, as already stated, the outer link 10 is shaped to have pad supporting means and has two flanges 16, located at a wall 26 and cooperating with the same wall 26 to accommodate therein a pad 18 made from a yielding material, such as rubber or plastic material,

possibly covered by a covering 20 made from cloth or similar, on the side designed to contact the containers, that move on the conveyor belt.

Opposed to the vulcanisation, that was usual till now in this art, according to the present invention, as better shown in figures 3a, 3b, 3c, 3d and 4a, 4b, 4c, a disengageable lock-joint is here used to carry out the connection between the pad support link 10 and pad 18 to prevent the slipping of the pad 18 relative to the pad supporting link 10, both in the longitudinal and cross directions.

Furthermore, it is to be clarified that, in the capping machines of the cited type, the restraint chains slide by resting the lower side of their outer links 10, at a frame rest surface 22, on the main frame of the machine (figure 2).

Slacking of the restraint chain in the cross direction is prevented by a longitudinal slideway 24, integral with the main frame, on which the inner links 12 rest during their motion in the longitudinal direction.

In such a way, the main component of the force needed to grip the container is discharged on the longitudinal slideway 24 and then on the frame of the machine, through the coupling of the inner surface of the wall 26 of the pad supporting link 10 (figure 3b) with the outer surface 28 of pad 18 (figure 4b).

Therefore, the disengageable joint, that couples the pad supporting link 10 and pad 18, only operates so as to avoid the longitudinal slipping that could happen owing to the motion of the container and due to cap closure operations that are carried out on the container itself inside the capping machine.

Furthermore, a joint cross component force must be present to prevent the pad 18 from fortuitously coming out of the pad supporting link 10, e. g. in the moment in which the pad 18 leaves the container after the end of closure operations.

With reference now to figures 3a, 3b, 3c, 3d and 4a,

4b, 4c, it is seen that the cross joint component, that opposes the longitudinal slipping between the pad 18 and the pad supporting link 10, consists of a pair of projections 30 on the flanges 16 of the link 10 and a corresponding pair of notches 32 on the pad 18. The longitudinal joint component, that opposes the cross slipping between the pad 18 and the pad supporting link 10, consists of a pair of projections 34 on the flanges 16 of the pad supporting link 10 and a corresponding pair of notches 36 on the pad 18.

Obviously, there is no need that two separate mechanical members respectively correspond to the longitudinal and cross components of the joint: on the contrary, it suffices that the joint is of a shape such that it provides for a lock in both directions, such as a dovetail lock.

Furthermore, the longitudinal joint component could be carried out by shaping the pad supporting link like a parallelepiped, i. e. with flanges on all four sides rather than on two sides only.

With reference to figures 5 and 6, in which parts similar to those described with reference to the previous figures are indicated with similar reference number provided with an apex, a second embodiment of a pad supporting link is now described, in which the pad 18'is locked by a pin 40. In order to avoid that pin 40 goes out, it is shaped so as to have a swell 42, which is inserted by interference fit into a hole performed into the pad 18', bringing the pad 18'into interference contact with the wall 26'. Obviously, it is also possible to use a cylindrical pin, in which case however a retainer must be applied in order to avoid any unexpected withdrawal.

Likewise, other locking means are useful for fastening the pad to the pad supporting link: it is only needed that the pad is locked in a mechanically disengageable way, instead of being fastened to the link by vulcanisation or gluing, as it'was the case before, according the known art.

However, the first embodiment, shown in figures 1 to 4,

is at present the preferred one, because of the realization simplicity of the mechanical members that comprise it.

Although reference has been made throughout the entire description to straight line capping machines, however it will be evident to the skilled in the art that a pad supporting link according to the present invention can be used in many other technical fields.

Obviously, other numerous and different variations and modifications may be made by the skilled in the art to the practical embodiments of the present invention herein described, without departing from the spirit and the scope of the invention as defined by the appended claims.