EP0013238B1 - Retractable gripper device for gripping hollow bodies within the mouth thereof - Google Patents

Abstract

Apparatus is described for grasping hollow bodies, such as bottles, from the inside. It is particularly useful in protecting grasping equipment used in conjunction with bottle coating equipment. On a movable rod inside a housing are mounted a structure adapted to engage the rim of the bottle and grasping arms which can be inserted into the neck of the bottle. The rod is spring-biased toward a position in which the structure and the grasping arms are retained within the housing. To grasp a bottle, a force is applied to the rod against this spring-bias so as to urge the rod, the structure and the grasping arms toward the bottle. At an intermediate point on the outward stroke, the structure is released from the rod. If the structure engages the rim of the bottle after its release and before the outward stroke ends, the structure is prevented by a slider from moving back into the housing and relative movement between the rod and the structure causes the grasping arms to engage the inside of the bottle. If, however, no bottle is present, the structure is resecured to the rod toward the end of its outward stroke and on the return stroke of the rod the structure is returned to within the housing. As a result, the grasping arms and rim engaging structure do not remain outside the housing and are not coated with the coating when a bottle is not present.

Description

The present invention relates to the gripping of hollow bodies such as bottles, flasks, jars, pots, tubes ... It relates more particularly to a new device for the gripping of such hollow bodies, in particular glass or plastic containers and their transfer to a surface treatment area at the end of manufacturing.

During the manufacture of hollow glass containers for example, different treatments can be applied to them. Thus, they can undergo a treatment which provides the glass surface with greater hardness thanks to a coating of metal oxide: this is the case of the "hot end" treatment. They can also undergo a treatment tending to improve or at least to preserve their mechanical properties thanks to a lubricating coating: this is the case of the "cold end" treatment. Finally, they can be coated with a layer of plastic material whose function is multiple, this layer plays in particular a role of protection against shocks, retention of splinters, increase in resistance to internal pressure and also possibly, it can give a better appearance to coated containers, and further reduce noise during subsequent handling.

Such treatment by coating a layer of plastic material is described for example in French patent application FR-A-2 315 323. This treatment is carried out in an area in which each of the containers, previously gripped by a gripping is conveyed by overhead conveyor.

Among these gripping devices, devices are known which are fitted with clamps which act on the outside of the neck of the container. In this case, coating of the cervix is impossible.

To overcome this drawback, gripping devices have been proposed equipped with clamps which penetrate into the opening of the container and come to be applied on the internal face of the neck. In this case the coating can be total.

However, another problem remains. In fact, at the loading station, upstream of the treatment zone, each gripping device must arrive opposite one of the regularly spaced containers arranged on a conveyor. There, the grippers of the gripper penetrate into the opening of the container to grasp it, and the assembly is then driven into the treatment area. However, it happens that a container accidentally dropped missing on the conveyor, in which case, the gripping device which was reserved for it continues its circuit without being loaded. Arrived in the treatment zone, the clamps not protected by the container are then coated with the treatment product which comes to foul them so that their functioning can be disturbed. In addition, when the gripping device concerned returns to the loading station after having followed a complete cycle, its grippers, by entering another container, deposit coating product inside. This product can then alter the taste of the future contents of the container.

The invention provides a gripping device for hollow bodies which overcomes the aforementioned drawbacks.

This gripping device has a member which penetrates into the opening of the hollow body to grasp it without coming into contact with the outside of the hollow body and which, in the rest position, that is to say unloaded, is completely eclipsed in a scabbard.

The device according to the invention comprises a sheath, a rod, a return spring for the rod in the sheath, pinching means arranged at the end of the rod (see FR-A-2 315 323), and is characterized in that it further comprises a nut surrounding the rod, the rod and the nut being able to slide inside the sheath in order to partially exit therefrom and fully return to it, the nut being intended to abut against the upper end of the hollow body, a crown which can move radially so as to make the nut alternately secured to the rod or sheath depending on the position of the nut and the rod relative to the sheath, the nut being secured to the rod at the start of its exit stroke and at the end of its return stroke, while it is secured to the sheath during the exit stroke in the intermediate position corresponding to the abutment of the nut against the end of the hollow body, which allows the actuation of the means of pinching by a mo relative uvement of return of the rod relative to the nut, and a movable ring in the sheath and which, when the rod and the nut undergo a complete stroke, keeps the nut integral with the rod during the end of its exit stroke and the start of its reentry race.

The clamping means can be a clamp comprising two branches articulated around an axis and able to be brought closer to one another by pivoting around this axis with a view to introducing it into the opening of the hollow body and then to move aside to come and press firmly against the internal walls of the opening.

In one embodiment of the device, the clamp comprises two branches articulated along parallel axes carried by the nut and between which is disposed the end of the rod comprising an appendage having flanks inclined symmetrically relative to the axis of the rod, the corresponding ends of the branches having a corresponding profile part which bears on said flanks, so that said appendage during a longitudinal movement of the rod between the branches causes said branches to spread apart inside the hollow body, by pivoting around their axis, acting on these branches like a wedge.

On the heel side of the branches, the upper can include a second appendage with inclined sides, capable of coming to bear on a part of the heel of the branches in order to cause them to close and to keep them in the closed position.

This closure means can also be replaced by an elastic return means.

The pinching means can be a sleeve formed of several sections held together by return springs, and which move apart under the action of the rod or axis provided with one or more appendages with conical sides.

The crown making the nut alternately integral with the rod or the sheath may comprise a finger which, by the action of a spring is applied alternately on the rod or on the sheath.

The pinching means can be carried by the nut. They can then include branches articulated on the nut, which move apart during the relative movement of the rod relative to the nut during the ascent. These pinching means can also be carried by a pin fixed to the lower end of the rod. They can then comprise a sleeve formed of at least two sections which are housed between two conical faces, which can be the end of the axis and a ring, the sections deviating during the relative movement of the rod relative to the nuts.

• la figure 1 représente, en élévation, le dispositif de préhension en position de repos,
• la figure 2 est une vue analogue du dispositif en présence d'un corps creux au poste de chargement,
• la figure 3 est une vue analogue du dispositif en présence d'un corps creux, à la sortie du poste de chargement,
• la figure 4 est une vue analogue du dispositif en absence de corps creux,
• la figure 5 est une vue en élévation d'une variante de dispositif en position de repos,
• la figure 6 est une vue analogue de cette variante en position de travail,
• les figures 7 et 8 représentent un détail de la deuxième variante du dispositif.

Other advantages and characteristics of the invention will appear in the following description of exemplary embodiments with reference to the figures:

• FIG. 1 shows, in elevation, the gripping device in the rest position,
• FIG. 2 is a similar view of the device in the presence of a hollow body at the loading station,
• FIG. 3 is a similar view of the device in the presence of a hollow body, at the outlet of the loading station,
• FIG. 4 is a similar view of the device in the absence of a hollow body,
• FIG. 5 is an elevation view of a variant device in the rest position,
• FIG. 6 is a similar view of this variant in the working position,
• Figures 7 and 8 show a detail of the second variant of the device.

In Figure 1, the device is shown at rest.

It comprises a sheath 1 on which a collar 3 is fixed by a pin 2, by which it bears on an element 4 of an endless chain. This sheath carries a sliding rod 5, the lower part of which has two grooves 6a and 6b terminated on either side by inclined sides 7a and 7b and 8a and 8b. Surrounding the rod, a hollow nut 9 carries, articulated on two axes 10a and 10b, two branches 11a and 11b which are housed in the grooves of the rod. A part of the profile of the branches is supported on the inclined sides 8a and 8b while a part of the profile of the heels is supported on the inclined sides 7a and 7b of the grooves.

At its upper end, the rod 5, provided with a washer 12, is recalled by a spring 13 interposed between this washer and the flange 3.

The bore of the bulging portion of the sheath has two sections bounded together by a shoulder F _I : a first section of diameter d and a second section of larger diameter D.

The middle part of the rod 5 can slide in the nut 9 which slides itself inside the bore 14 of section d of the sleeve. This nut 9 has flanks 15 of conical shape on which slides a crown 16 divided into three sectors, one of which 17 is provided in its center with a finger 18 passing through an opening 19 provided in the nut 9, to enter a groove 20 of rod 5 which it locks. Overcoming the crown 16, a ring 21 is applied against it by the action of a spring 22 fixed on the upper end of the nut 9.

The lower part of diameter D of the bore of the sleeve contains a ring 23 of internal diameter equal to d which can slide in the bore of diameter D of the sleeve, between the shoulder F ₁ and a circlip 25, and the cross section of which upper form a truncated cone.

The device also has a toothed wheel 26 rigidly mounted on the sheath and which can drive the assembly, and consequently the hollow body, in rotation about its axis in the subsequent treatment zone.

The operation of the device is now described in relation to Figures 2, 3 and 4 which at various times represent the positions of the different elements.

At the loading station, an external member, for example a stud mounted on an energetic spring on an articulated track which follows the advance movement of the gripping devices exerts a determined force P, for example greater than 15 kg on the upper end of the rod 5. This rod descends by compressing the spring 13 driving the nut 9 through the shoulder F ₂ as well as the sectors of the crown 16 whose finger 18 is engaged in the groove 20.

Arrived in the bore of diameter D, the sectors of the crown 16 pushed by the ring 21 under the action of the spring 22 slide on the inclined flanks of the nut 9, and come to be applied on the inner face of the bore D. The finger 18 releases the throat from the rod 5. The two branches penetrate the hollow body.

The descent of the rod 5 is then limited after a stroke of 85 millimeters for example by the presence of the object to be grasped which comes into contact with the underside 27 of the nut 9. At this time the crown 16 is in the bore of diameter D of the sleeve.

When we remove the action of the external pusher on the rod 5, it rises under the action of the spring 13 driving the assembly over a few millimeters. The crown 16 is then blocked by the shoulder F ₁ and it retains the nut 9 and the branches 11 a and 11 b. Going up, the rod 5 spreads, by its sides 8a and 8b the two branches 11a and 11b which pivot around the axes 10a and 10b and are applied against the interior walls of the hollow object. The hollow corsp, seized, is then entrained in the zone of subsequent treatment, the action of the branches being maintained constantly during all the treatment.

, At the unloading station, another pusher member presses on the rod 5 which performs a complete stroke, for example of 100 mm, no resistance opposing its descent, the conveyor which receives the hollow body being located at a distance from the sheath accordingly, and for example 3 cm greater than that which separated the sheath from the conveyor to the loading station. The two branches 11a and 11b meet, freeing the hollow body, the nut 9 fully engages in the bore of diameter d of the ring 23. The sectors of the crown 16 slide over the conical section of the ring 23 and engage inside while exerting against its walls a force directed towards the outside due to the action of the spring 22 and the flanks 15 of conical shape of the nut 9. At the same time, the finger 18 engages again in the groove 20 of the rod 5 and locks it again.

After suppressing the action of the pusher on the rod 5, the spring 13 rises it at the same time as the ring 23 and the elements it contains. The top of the ring 23 comes into contact with the shoulder F _{1 ′} the crown 16, the nut 9 and the ring 20 continue to rise in the bore of diameter d until they come into abutment in the upper part of this bore . The forceps have returned to their initial position, completely eclipsed in the sheath. The ring 23 released from the action of the sectors of the crown returns to its initial low position.

In the absence of objects at the loading station, the descent of the rod is no longer limited by the object to be grasped and the rod performs a full stroke. The movement begins as in the case of the presence of an object and it continues as in the case of unloading, that is to say that the sectors of the crown 16 slide on the conical section of the ring 23 and there engage while applying against its walls, that the finger 18 again engages in the groove 20 of the rod 5 and locks it and that, after suppressing the action of the pusher, the rod 5, under the action of the spring rises, causing the assembly which comes to slip away in the sheath.

Finally, at the exit of the loading station, in the absence of objects, the clamp returned to its initial position completely eclipsed in the sheath. Thus, when the device arrives in the treatment zone, the sprayed product, for example by spraying, cannot reach and contaminate the penetrating organ.

Figures 5 and 6 show a variant of the gripping device in which the branches are replaced by an expandable sleeve formed of three sections.

The device has a structure similar to that of the device already described and comprises largely the same elements, namely: a sleeve 1 of bore D and d in which slide the nut 9, the crown 16 with three sectors, the ring 21 , the spring 22, the ring 23.

In this variant, the rod 5 is provided with a pin 101 screwed onto it which ends in a double cone 102. A ring 103 finished in the shape of a cone 104 slides freely on the pin 101.

Between the cone 102 and the ring 103 is housed a sleeve 105 formed of three sections 106, 107, 108 as shown in FIGS. 7 and 8.

These three sections are held together by three extension springs 109, mounted in a crown, which are housed in three grooves 110.

The material of the sleeve can be a metal or a plastic material such as polyamides. It must withstand a temperature of the order of 250 ° C. in the case of a treatment for coating the containers with a plastic material for example.

The operation of this variant of said ^p tif OSi is analogous to that already described.

Under the action of an external pusher member, the rod 5 descends, driving all of the elements inside the sheath as already described and the sleeve 105 enters the hollow body. When the underside 111 of the ring 3 comes into contact with the hollow body to be gripped, the crown 16 is located in the bore of diameter D of the sleeve.

When the action P of the pusher on the rod 5 is removed, the latter rises, driving the axis 101, the cone 102 of which spreads the three sections of the sleeve from below, separated simultaneously, at the top by the conical part 104 of the ring 103 blocked by the ring 3 itself blocked by the crown 16. By deviating, the three sections of the sleeve are applied firmly on the inner wall of the hollow body to be gripped.

Claims (6)

1. Device for gripping hollow bodies in the interior of the latter, comprising a sheath (1), a stem (5), a return spring (13) for the stem in the sheath, and clamping means (11) arranged at the end of the stem, characterised in that it further comprises a bush (9) surrounding the stem, the stem and the bush being capable of sliding inside the sheath to extend from it partially and be totally withdrawn within it, the bush being arranged to come into abutment against the upper end of the hollow body, a ring (16) which is movable radially so as to connect the bush with the stem or the sheath according to the position of the bush and the stem with respect to the sheath, the bush being connected to the stem at the start of its path of movement in extension and at the end of its path of movement to withdraw and being connected to the sheath during its movement in extension at an intermediate position corresponding to abutment of the bush against the end of the hollow body, thus allowing actuation of the clamping means by a relative return movement of the stem relative to the bush, and a sleeve (23) movable in the sheath and which, when the stem and bush move over a complete path, holds the bush connected to the stem during the end of its path of movement in extension, and the start of its path of movement to withdraw.

2. Device according to claim 1, characterised in that the end of the stem (5) controls the action of the clamping means by separating them so that they come into contact with the internal wall of the hollow body.

3. Device according to claim 2, characterised in that the clamping means are a clamp comprising two arms (11a, 11b) articulated on parallel axes carried by the bush (9) and between which is arranged the end of the stem (5) comprising an extension having sides (8a, 8b) inclined symmetrically with respect to the axis of the stem, the corresponding ends of the arms having a part of corresponding profile which comes into contact with said sides, so that said extension during longitudinal movement of the stem between the arms causes separation of said arms inside the hollow body by pivoting about their axis, acting on the arms in the manner of a wedge.

4. Device according to claim 2, characterised in that the clamping means comprises a sleeve (105) formed of at least two parts held together by at least one spring, this sleeve being positioned between a conical surface of an axis (101) fixed at the end of the stem (5) and a ring (103) having a conical surface mounted to slide about the axis (101).

5. Device according to one of claims 1 to 4, characterised in that the ring (16) connecting the bush alternatively to the stem and the sheath comprises a finger (18) which under the action of a spring is applied alternatively to the stem or the sheath.

6. Device according to one of claims 1 to 5, characterised in that the sheath (1) has an opening of diameter d in which the bush (9) slides at the start of its path of movement in extension and the end of its path of movement to withdraw, and an opening of larger diameter D arranged in its lower part, in which slides the ring (23) which itself has an internal diameter d.

Images