FR3135911A1 - Suction cup for vacuum handling device - Google Patents

Abstract

Suction cup comprising a bellows (1) having a first end (1.1) and a second end (1.2) along a longitudinal axis (2.1), a bottom wall (5) provided at the first end, a first plate (6 ) equipping the first end, a sealing skirt (7) provided on the second end, characterized in that the suction cup comprises a second plate (8) which is fixed on the second end of the bellows, set back from a free edge of the sealing skirt, and a rigid support (9), fixed to the second plate and in contact with the sealing skirt, carrying a sealing flange (10) which delimits a closed contour and which is arranged to be applied by the support against a surface of an object to be grasped while deforming elastically. ABSTRACT FIGURE: Fig. 2

Description

Suction cup for vacuum handling device

The present invention relates to a suction cup for vacuum handling equipment such as for example a bottle handler.

BACKGROUND OF THE INVENTION

The handling of certain objects is carried out by automated arms, or manipulators, at the end of which the gripping member is a vacuum suction cup.

The classic structure of such a suction cup comprises a flexible and elastic bellows, of generally circular or oval shape having a free edge provided with an annular skirt which, when applied to the object to be grasped, isolates the internal volume of the bellows from the external atmosphere so that this volume can be connected to a vacuum source. The vacuum thus established in the chamber of the suction cup is never absolute and the force with which the suction cup adheres to the object is therefore less than the surface of the object circumscribed by the edge of the bellows, multiplied by the atmospheric pressure. This force therefore determines the maximum weight of the object that the suction cup can support.

The suction cup chamber is connected to the atmosphere by means of a controlled valve.

It is usual, in this type of suction cups, that the bellows comprises on the one hand an upper insert which forms a plate for fixing the suction cup to the manipulator and a support plate for the aforementioned valve and the pneumatic conduit, and, on the other hand , ring-shaped peripheral stiffeners housed in the outer folds of the bellows. The controlled valve is normally closed when the suction cup is out of service, that is to say when the suction cup is not facing any part to be gripped, which is the case when a machine has a plurality of suction cups for gripping fewer parts than the suction cups. When the suction cup comes into contact with the part to be treated, the bellows crushes and a pusher, carried by the bellows which rests on the part, lifts the valve from its seat. Depression can then be established in the suction cup chamber. When it comes to releasing the part, the suction is interrupted and atmospheric air (or a blowing gas) passes through the still open valve and fills the chamber of the suction cup. The manipulator can then move the suction cup away from the object, the pusher leaves the surface of the object and the suction circuit is closed by the valve under the effect of a return spring provided for this purpose, which avoids a loss of energy.

These suction cups work generally well but it has however appeared that certain objects to be grasped have shapes, and in particular cylindrical shapes, which do not allow the establishment of a sufficient vacuum to allow the grip of these objects.

OBJECT OF THE INVENTION

The object of the invention is to provide a suction cup which at least partly remedies the aforementioned drawbacks.

This is how the subject of the invention is a bellows suction cup comprising a bellows having a first end and a second end along a longitudinal axis, a bottom wall provided at the first end, a first plate equipping the first end, a sealing skirt provided on the second end, characterized in that the suction cup comprises a second plate which is fixed on the second end of the bellows, set back from a free edge of the sealing skirt, and a support rigid, fixed to the second plate and in contact with the sealing skirt, carrying a sealing bead which delimits a closed contour and which is arranged to be applied by the support against a surface of an object to be gripped by deforming elastically.

We noticed that the combination of a bellows with a support of a sealing ring ensures a grip more suited to certain shapes of objects to be gripped.

Other characteristics and advantages of the invention will emerge from the non-limiting description of the invention, given below of an example of embodiment of the invention.

Reference will be made to the attached drawings, including:

there is a perspective view of a suction cup according to the invention, engaged with a bottle;

there is an exploded view of this suction cup, with stiffeners positioned in the same direction;

there is an axial sectional view of this suction cup according to a plane III of the , but with stiffeners positioned head to tail;

there is an axial sectional view of this suction cup according to a plane IV of the , the stiffeners being positioned in the same direction;

there is a perspective view, from below, of this suction cup.

DETAILED DESCRIPTION OF THE INVENTION

With reference to the figures, the suction cup of the invention is here more particularly described in application to the gripping of a bottle B whose external surface, of cylindrical shape with circular section centered on a longitudinal axis A of the bottle B, is provided of helical reliefs winding around the longitudinal axis A of the bottle B. Nevertheless, the invention can be used or can be adapted for gripping other types of objects, having different shapes, revolution or not , regular or irregular…

The suction cup of the invention, generally designated V, comprises a bellows 1 which forms a deformable side wall along a longitudinal axis 2.1 of the suction cup V and the bellows 1. The cross section of the bellows 1 of the suction cup V can be circular or oblong. The cross section of the bellows 1 of the suction cup V here has a substantially rectangular cross section with a major axis 2.2 and a minor axis 2.3, with two long straight sides and two small rounded sides. Note that the bellows 1 is capable of accepting a rotational force around the axis A of the bottle.

The bellows 1 has a first end 1.1, or upper end, and a second end 1.2, or lower end, successively along the longitudinal axis 2.1. Between these two ends, the bellows 1 comprises four “v”-shaped folds connected in pairs by a connecting portion, each fold having a maximum cross section greater than the cross section of the connecting portion. In each of the folds of the bellows 1, the suction cup V comprises a stiffener 3 which extends, in the fold, transversely to the longitudinal axis 2.1 so as to prevent collapse towards the center of the side wall of the bellows 1 when the interior chamber 4 delimited by bellows 1 is subjected to a depression. Each stiffener 3 is here formed by a metal wire which has been plastically deformed to form an open and elastically deformable rectangle fitting into the maximum cross section of the fold of the bellows 1. The ends of the metal wire are shaped into a loop allowing them to be brought together using pliers and putting each stiffener 3 in place in one of the folds of the bellows 1 (like putting an elastic “circlip” ring in a groove of a bore).

The first end 1.1 is provided with a bottom wall 5 which covers a first plate 6 by means of which the suction cup V can be fixed to the mobile end of a handling gripper P like the wrist of a robot arm or on a lower surface of a box having an upper surface attached to the lower end of a lifting tube. The first plate 6 is embedded in an internal groove of the first end 1.1 of the bellows 1. The first plate 6 is also the support of a seat for a valve not shown, surrounding a pneumatic conduit provided in the plate 6 and the wall of bottom 5 of the suction cup V. This conduit is connected to a vacuum source not shown. In a manner known in itself, the valve is integral with a pusher which passes through the conduit to extend to a second plate 8 consisting of a lower insert in the form of a perforated plate whose periphery is embedded in the second end 1.2 of the bellows 1. The pusher is for example an inextensible and incompressible deformable wire whose end secured to the valve is fixed to the latter also by means of a radial screw. A spring surrounds the pusher and tends to move the lower insert away from the valve seat.

The second end 1.2 of the bellows 1 is provided with a sealing skirt (or lip) 7 which is in one piece with the bellows 1 and which extends axially from the second end 1.2 of the bellows 1 in s escaping from it. The second plate 8 is embedded in an internal groove of the second end 1.2 set back from the sealing skirt 7 and a support plate 9 extending outside the bellows 1 is fixed to the second plate 8 by screws such that the sealing skirt 7 is pressed against an upper surface 9.1 of the support plate 9. Conversely, the support plate 9 comprises a lower surface 9.2 carrying a sealing flange 10 delimiting a closed contour.

The lower surface 9.2 of the support plate 9 has a shape at least partly complementary to an external shape of the object to be grasped. More precisely here, the lower surface 9.2 of the support plate 9 comprises a concave arc portion of a generator cylinder parallel to the major axis 2.2. When the suction cup V is positioned relative to the bottle B in such a way that the major axis 2.2 and the longitudinal axis 2.1 of the suction cup V are in the same plane with the longitudinal axis A and the latter is perpendicular to the longitudinal axis 2.1, the lower surface 9.2 of the support plate 9 is complementary to the external shape of the bottle B.

The sealing ring 10 here has a small rectangular cross section with a major axis parallel to the longitudinal axis 2.1 and is made of elastically deformable foam, for example elastomer, or silicone. The sealing ring 10 is glued over its entire length to the lower surface 9.2 so as to ensure tight contact between the support plate 9 and the object to be gripped, namely the bottle B. The support plate 9 is said to be rigid in that meaning that it is more rigid than the sealing ring 10 which will deform elastically on contact with the object to be gripped while the support plate 9 will retain its shape.

In service, the vacuum conduit not shown is connected to the suction source of the gripping machine P.

The suction cup V is brought close to the bottle B in such a way that the major axis 2.2 and the longitudinal axis 2.1 of the suction cup V are in the same plane with the longitudinal axis A and that the latter is perpendicular to the longitudinal axis 2.1 .

When the flange 10 of the suction cup V comes into contact with the bottle B and the bringing together movement continues, the second plate 8 is moved towards the plate 6 and the valve is lifted from its seat. The vacuum is established in the chamber 4 of the suction cup V which generates the gripping force at the same time as an axial contraction of the bellows 1. Due to the elastic deformability of the tube and here the shape of the lower surface 9.2 of the support plate 9, a tight contact is established between the flange 10 and the exterior surface of the bottle B ensuring effective gripping.

Note that the pusher, due to its wired nature, can deform (undulate) to absorb the contraction and deformation of the bellows while the valve remains raised.

When bottle B is removed, the vacuum ceases in the conduit upstream of the valve, by appropriate control of the gripper, and chamber 4 is placed in communication with the atmosphere or with a source of compressed air intended to quickly fill bellows 1. Bellows 1 extends and the valve returns to its seat while the gripping force is canceled. The object is then released, chamber 4 is again isolated from the vacuum conduit located beyond the valve in relation to the first plate 6. A new gripping cycle can then begin again. Closing of the valve must therefore coincide with a pressure in chamber 4 at least equal to atmospheric pressure. We understand that if the behavior of bellows 1 has varied over time, this adjusted coincidence may not be preserved during the initial adjustment of the machine.

Of course, the invention is not limited to the embodiment described but encompasses any variant falling within the scope of the invention as defined in the preceding summary.

In particular, the structure of the suction cup and its connection to the gripper may be different.

The sealing ring can be fixed by means other than gluing, and for example by fitting into a groove.

The sealing ring can be fixed to a side surface of the support plate or to a rigid element attached to the support plate.

The sealing ring may have a section different from that indicated, that is to say other than rectangular and for example circular or trapezoidal.

The sealing ring can be made of a porous, semi-porous, or non-porous material, be in the form of a gel, etc.

The suction cup bellows may have more or less creases.

The suction cup may have a different flap arrangement.

The invention relates to a gripper comprising a box provided with means for connecting it to a pneumatic circuit and at least one suction cup. The gripper can be equipped with one or more suction cups according to the invention.

In use, axis 2.1 of bellows 1 is not necessarily vertical as on the .

Claims (7)

Suction cup comprising a bellows (1) having a first end (1.1) and a second end (1.2) along a longitudinal axis (2.1), a bottom wall (5) provided at the first end, a first plate (6 ) equipping the first end, a sealing skirt (7) provided on the second end, characterized in that the suction cup comprises a second plate (8) which is fixed on the second end of the bellows, set back from a free edge of the sealing skirt, and a rigid support (9), fixed to the second plate and in contact with the sealing skirt, carrying a sealing flange (10) which delimits a closed contour and which is arranged to be applied by the support against a surface of an object to be grasped while deforming elastically. Suction cup according to claim 1, in which the sealing ring (10) is integral with a lower surface (9.2) of the support (9). Suction cup according to claim 2, in which the lower surface (9.2) of the support (9) has a shape at least partly complementary to an external shape of the object to be grasped. Suction cup according to one of the preceding claims, in which the sealing ring (10) is made of elastically deformable foam. Suction cup according to one of claims 1 to 3, in which the sealing ring (10) is made of silicone. Suction cup according to one of the preceding claims, in which the sealing ring (10) has a small rectangular cross section. Gripper (P) comprising a box provided with means for connecting it to a pneumatic circuit and at least one suction cup (V) according to any one of the preceding claims.