Technical Field

The present invention relates to a manipulation gripper.

Background Art

The use of manipulation grippers for the transfer of products between various machining stations is well known in most industries.

Manipulation grippers are generally mounted on robotic apparatuses, such as articulated arms, anthropomorphic robots or the like, which are responsible for the movement of the grippers themselves.

Manipulation grippers include vacuum grippers provided with soft jaws, made of elastically deformable material such as e.g. rubber or silicone, intended for manipulating fragile and/or delicate products.

Such grippers find special application in the food industry where it is necessary to work on soft and/or delicate products, such as fruits, vegetables, baked products, etc., and where the use of rigid jaws could cause the products themselves to be damaged or deformed.

Vacuum grippers of known type comprise a gripping unit made at least partly of an elastically deformable material and provided with a base portion defining an inner chamber and at least two jaws associated with the base portion.

Vacuum grippers of known type also comprise a suction unit which is connected to the gripping unit in a fluid-operated maimer and operable to draw air from the inner chamber and to determine a deformation of the base portion. Deformation of the base portion induces a mutual movement of the jaws relative to a central axis, between a position of maximum opening, wherein they are arranged away from each other at a maximum mutual distance, and a position of maximum closing, wherein they are arranged closer to each other at a minimum mutual distance.

In detail, the operation of the suction unit causes a vacuum within the inner chamber that induces the deformation of the base portion and the movement of the jaws from the position of maximum opening to the position of maximum closing. The deactivation of the suction unit, on the other hand, results in the restoration of the atmospheric pressure in the inner chamber and of the original conformation of the base portion, causing the jaws to move from the position of maximum closing to the position of maximum opening.

The suction unit substantially determines the movement of the jaws exclusively between the two aforementioned positions.

Vacuum grippers of known type have some drawbacks related to the fact that the position of maximum opening of the jaws does not allow easy gripping of products to be manipulated which are significantly smaller than the maximum mutual distance between the jaws, especially in the presence of additional products and/or components of equipment adjacent to them.

In the latter case, in fact, the jaws may collide such products and/or adjacent components and fail to effectively intercept the product to be manipulated when closed.

To overcome this drawback, it is necessary to have a plurality of different grippers wherein, in the position of maximum opening, the jaws are arranged with each other at different mutual distances, so as not to be excessively cumbersome with respect to the product to be manipulated.

It is clear how this leads to increased production costs that are reflected in the retail price of the finished product.

In addition to this, the need to frequently replace the grippers depending on the type of product to be handled inevitably results in longer production time frames.

Description of the Invention

The main aim of the present invention is to devise a manipulation gripper which allows effective grasping of the products to be manipulated of small size even in the presence of additional products and/or adjacent components.

Another object of the present invention is to devise a manipulation gripper which allows reducing production costs and related time frames.

Another object of the present invention is to devise a manipulation gripper which allows the aforementioned drawbacks of the prior art to be overcome within the framework of a simple, rational, easy and effective to use as well as affordable solution.

The aforementioned objects are achieved by this manipulation gripper having the characteristics of claim 1.

Other characteristics and advantages of the present invention will become more apparent from the description of a preferred, but not exclusive, embodiment of a manipulation gripper, illustrated by way of an indicative yet non-limiting example, in the attached tables of drawings in which:

Figure 1 is an axonometric view of an appliance for the production of stuffed cheese mounting the manipulation gripper according to the invention;

Figure 2 is an axonometric view of the manipulation gripper according to the invention, with the adjustment means in the home position;

Figure 3 is an axonometric view of the manipulation gripper according to the invention, with the adjustment means in the working position;

Figure 4 is a sectional view of the manipulation gripper according to the invention;

Figure 5 is a front view of the manipulation gripper according to the invention, with the holding means in the holding position;

Figure 6 is an axonometric view of the manipulation gripper according to the invention, with the holding means in the release position;

Figures 7 and 8 are axonometric views of the manipulation gripper according to the invention from different angles.

Embodiments of the Invention

With particular reference to these figures, reference numeral 1 globally denotes a manipulation gripper.

The manipulation gripper is intended for the manipulation of soft and/or delicate products in order to reduce the risk of damage and/or deformation of the products themselves.

In particular, Figure 1 shows a possible application of the manipulation gripper wherein the latter is mounted on an appliance A for the production of stuffed cheese, of the burrata type. In detail, in this specific case, the manipulation gripper is intended for the manipulation of fresh cheese of the stretched type.

In more detail, the manipulation gripper 1 is intended for the transfer of cheese from a forming machine F to respective container elements B of a filling machine M.

In this regard, it is worth specifying that, as is well known, the production processes of stuffed cheese generally involve hot treatment of cheese in order to preserve the elasticity and deformability of the paste and to allow the filling to take place while avoiding tearing and/or breakage. Specifically, the cheese is treated at a temperature of between 50°C and 70°C.

It is easy to appreciate how, at such temperatures, the manipulation of cheese by an operator is rather unpleasant and detrimental to the operator’s health, and can cause the operator to grasp the cheese improperly, thus risking compromising its elastic properties and/or appearance.

The use of a manipulation gripper is therefore extremely advantageous for this application.

In addition, the manipulation gripper makes it possible to speed up cheese transfer operations and prevents excessive cooling of the same.

Again, the use of a manipulation gripper helps to increase the hygienic conditions of the finished product.

The manipulation gripper 1, shown in greater detail in Figures 2 through 8, comprises: at least one base support 2 associable with an automated positioning system P; and retaining means 3 associated with the base support 2 and adapted to grasp a product to be manipulated.

In more detail, in accordance with the embodiment shown in Figure 1, the automated positioning system P comprises a delta robot. It cannot, however, be ruled out that the automated positioning system P may comprise a different type of device, e.g., of the type of an anthropomorphic robotic arm or a collaborative robot. The retaining means 3 are provided with at least one gripping unit 4 made at least partly of an elastically deformable material.

Preferably, the elastically deformable material is silicone. It cannot, however, be ruled out that the elastically deformable material is of a different type, e.g., rubber.

Specifically, the gripping unit 4 is of the type of a vacuum gripper.

In detail, the gripping unit 4 comprises at least one base portion 5 defining an inner chamber 6 and at least two jaws 7 associated with the base portion 5.

Each of the jaws 7 comprises a main portion 8 associated with the base portion 5, of elongated conformation, and a gripping portion 9 associated with the main portion 8 and opposite the base portion 5.

The gripping portions 9 are intended to contact the product to be manipulated and may have a knurled inner surface adapted to reduce the risk of the product slipping out of the gripping unit 4.

As a result of a deformation of the base portion 5, the jaws 7 are mutually movable with respect to a central axis C, between a position of maximum opening, wherein they are arranged away from each other at a maximum mutual distance, and a position of maximum closing, wherein they are arranged close to each other at a minimum mutual distance.

In accordance with the embodiment shown in the figures, the gripping unit 4 comprises three jaws 7 arranged around the central axis C in a radial pattern.

The deformation of the base portion 5 results in contextual movement of the jaws 7 towards the central axis C.

The retaining means 3 also comprise at least one suction unit 10 connected to the gripping unit 4 in a fluid-operated maimer and operable to draw air from the inner chamber 6 and to determine the movement of the jaws 7 from the position of maximum opening to the position of maximum closing.

In detail, the activation of the suction unit 10 causes a vacuum inside the inner chamber 6 which induces the deformation of the base portion 5.

The deactivation of the suction unit 10, on the other hand, causes the restoration of the atmospheric pressure within the inner chamber 6 and of the original conformation of the base portion 5, causing the jaws 7 to move from the position of maximum closure to the position of maximum opening.

The suction unit 10 substantially causes the movement of the jaws 7 exclusively between the two aforementioned positions.

In accordance with a preferred embodiment, the suction unit 10 comprises a decentralized ejecting device.

According to the invention, the manipulation gripper 1 comprises adjustment means 11 associated with the retaining means 3 and adapted to vary the mutual distance of the jaws 7 in the position of maximum opening.

More specifically, the adjustment means 11 are configured to reduce the mutual distance between the jaws 7.

In this way, the manipulation gripper 1 allows even small products to be grasped easily, thus avoiding the need for a plurality of different grippers and the need for constant replacement jobs.

The adjustment means 11 comprise at least one adjustment body 12 arranged to wrap at least partly around the gripping unit 4 and movable between a home position, wherein it is moved away from the jaws 7 (Figures 2 and 4), and at least one working position, wherein it is in contact with the jaws 7 and exerts a pressing force thereon towards the central axis C (Figure 3).

In the working position, the adjustment body 12 is configured to contact the main portions 8 of the jaws 7.

In more detail, in the working position the adjustment body 12 is arranged to wrap at least partly around the main portions 8.

Again, conveniently, in the working position, the adjustment body 12 is configured to vary the inclination of the main portions 8 with respect to the central axis C.

Specifically, in accordance with the embodiment shown in the figures, in the position of maximum opening, the main portions 8 are inclined with respect to the central axis C and converging towards the base portion 5.

In the home position, on the other hand, the adjustment body 12 is arranged where the base portion 5 is located. Advantageously, the adjustment body 12 is of substantially cylindrical conformation and is movable by sliding along the central axis C between the home position and the working position.

For this purpose, the adjustment means 11 comprise a movement assembly 13 adapted to move the adjustment body 12.

In accordance with the preferred embodiment shown in the figures, the movement assembly 13 comprises: at least one supporting body 14 attached to the retaining means 3 and supporting the adjustment body 12 by screwing; and at least one crown gear 15 associated rotatable with the supporting body 14 and coupled to the adjustment body 12.

The rotation of the crown gear 15 causes the adjustment body 12 to slide with respect to the supporting body 14 between the home position and the working position.

The supporting body 14 and the adjustment body 12 are substantially screwed onto each other and the mutual rotation between the two causes the adjustment body 12 to slide.

Conveniently, the supporting body 14 comprises a screw portion 16 and the adjustment body 12 comprises a nut-screw portion 17. In other words, the adjustment body 12 is arranged externally to the supporting body 14.

The screw portion 16 and the nut-screw portion 17 have relevant threads with a very small pitch so as to allow the fine adjustment of the sliding of the adjustment body 12.

The supporting body 14 is of tubular conformation and is arranged where the base portion 5 is located.

In addition, the supporting body 14 comprises a housing portion 18 adapted to receive the crown gear 15, which is arranged to surround the supporting body 14.

Conveniently, the crown gear 15 comprises at least one protruding portion 19 and the adjustment body 12 comprises a relevant recess 20 adapted to accommodate the protruding portion 19. The rotation of the crown gear 15 causes the rotation of the protruding portion 19 which drags the adjustment body 12 by interaction with the recess 20.

As can be easily appreciated, the rotation of the crown gear 15 in one way of rotation causes the sliding of the adjustment body 12 in one direction, while the rotation of the crown gear 15 in the opposite way of rotation causes the sliding of the adjustment body 12 in the opposite direction.

The movement assembly 13 also comprises at least one actuator system 21 comprising at least one pinion body 22 meshing on the crown gear 15 and at least one motorized device 23 connected to the pinion body 22 and adapted to set the pinion body itself in rotation.

Specifically, in the embodiment shown in the figures, the movement assembly 13 comprises a connecting crown wheel 24, positioned between the pinion body 22 and the crown gear 15.

Advantageously, the manipulation gripper 1 also comprises holding means 25 associated with the base support 2 and adapted to hold in support the product to be manipulated which is retained by the retaining means 3.

Specifically, the holding means 25 are adapted to hold the product during the transfer operations and prevent the product from any possible accidental falling. In addition to this, with special reference to the intended use shown in Figure 1, as shown above, stretched cheese is generally worked by heat in order to take advantage of the elasticity and deformability of the paste.

It is, therefore, possible that, as a result of the movement of the manipulation gripper 1 by the automated positioning system, the cheese may become deformed due to the force of gravity and the additional forces involved. Excessive deformation, moreover, could induce the cheese to slip off the retaining means 3.

The holding means 25 provide support for the cheese and prevent the cheese from becoming excessively deformed, thus avoiding the aforementioned problems.

Specifically, the holding means 25 are provided with at least one plate 26 movable with respect to the retaining means 3 between a holding position, wherein it is arranged inferiorly to the gripping unit 4 (Figure 5), and a release position, wherein it is moved away from the gripping unit 4 (Figure 6).

In order to release the product, in fact, the plate 26 should be displaced with respect to the holding position so as to allow the product to fall.

Conveniently, the plate 26 is of curved conformation and has a concavity facing the gripping unit 4, so as to effectively hold the product to be manipulated.

Advantageously, the holding means 25 comprise: at least one supporting structure 27 supporting the plate 26 and associated rotatable with the base support 2; and at least one rotation assembly 28 associated with the base support 2 and adapted to set the supporting structure 27 in rotation around an axis of rotation R between the holding position and the release position.

The plate 26 is rotationally locked together with the supporting structure 27 Conveniently, the axis of rotation R is substantially perpendicular to the central axis C and incident thereto.

The central axis C and the axis of rotation R substantially lie on the same plane. This arrangement gives the holding means 25 the minimum rotational encumbrance volume.

In fact, if the axis of rotation R were not incident the central axis C, i.e., if it were spaced with respect thereto, the volume occupied by the holding means 25 during rotation would be greater with the risk of colliding with additional objects in the proximity thereof.

For example, with reference to the application shown in Figure 1, when placing a wheel of cheese in a respective container element B, the rotation of the holding means 25 could cause the plate 26 and/or the supporting structure 27 to collide with adjacent container elements B.

In addition to this, the plate 26 is advantageously shaped as a cylinder portion having an axis substantially parallel to the axis of rotation R.

In this way, the overall dimensions of the holding means 25 during rotation are further reduced.

The rotation assembly 28 comprises at least one actuator 29 housed within the base support 2 and provided with a drive shaft 30 extending along the axis of rotation R.

The rotation assembly 28 also comprises a guidance unit 31 comprising a pin 32 associated with the supporting structure 27 and a seat 33 defined on the base support 2 and accommodating the pin 32 by sliding.

The conformations of the seat 33 and of the pin 32 define the end-of-stroke positions of the supporting structure 27 which correspond to the holding position and to the release position of the plate 26.

The rotation assembly 28 also comprises a shock absorber system provided with at least one pair of hydraulic decelerators 34.

In addition, the rotation assembly 28 also comprises a pair of sensors 35 adapted to detect the position of the supporting structure 27 with respect to the base support 2 and, consequently, of the plate 26 in the holding position and in the release position.

Advantageously, the holding means 25 also comprise at least one shifting assembly 36 associated with the supporting structure 27 and adapted to move the plate 26 with respect to the supporting structure 27 along a direction of shift T close to/away from the gripping unit 4.

Specifically, with the supporting structure 27 in the holding position, the direction of shift T is substantially parallel to the central axis C.

The shifting assembly 36 allows the volume defined between the gripping unit 4 and the plate 26 to be adjusted depending on the size of the product to be manipulated. In the case of small products, the plate 26 is placed in the proximity of the gripping unit 4, while in the case of large products, the plate 26 is placed at a greater distance from the gripping unit 4.

In addition, the shifting assembly 36 allows the plate 26 to be moved away from the product prior to the rotation of the supporting structure 27 towards the release position.

By doing so, it is possible to prevent the plate 26 from dragging the product with it during rotation. This peculiar feature is particularly advantageous in the case of products to be manipulated which are deformable, such as precisely fresh stretched cheese.

Conveniently, as shown in Figure 7, the shifting assembly 36 comprises: at least one electric motor 37 attached to the supporting structure 27 and provided with an evolving screw shaft 38 extending along the direction of shift T; and at least one pinion 39 associated with the plate 26 and meshing on the shaft 38.

The rotation of the shaft 38 causes the plate 26 to shift along the direction of shift T. It has in practice been ascertained that the described invention achieves the intended objects and, in particular, the fact is emphasized that the manipulation gripper according to the invention allows effective grasping of the products to be manipulated of different sizes.

In addition, this manipulation gripper allows effective grasping of the products to be manipulated even in the presence of additional products and/or adjacent components.

Finally, the present gripper makes it possible to reduce production costs and the related time frames.