Gripping device for vacuum chamber

Abstract

Gripping member (20) for vacuum chamber, comprising a tubular body (21) which has a section (21.1) delimiting a cavity in which is mounted sliding a hollow piston (24) defining with the walls of the first cavity a first chamber (C1) of variable volume into which opens a compressed air conduit (S), the piston being provided, opposite the first chamber, with a tubular extension (25) having a free end section projecting from the first cavity and provided with a suction cup, the piston and the tubular extension defining a suction channel (25.1) having an end which opens into the suction cup (26) and an opposite end which receives by sliding sealing a rod (29), the tubular extension having at least one suction orifice (25.2) to connect the suction channel to a second chamber (C2) under vacuum, and the piston being mounted to move in translation relative to the rod between a rest position in which the rod obstructs the suction orifice and a gripping position in which the rod is withdrawn from the suction orifice. FIGURE IN ABRIDGED DIAGRAM: Fig.1.

Description

Title of the invention: Gripping device for vacuum chamber

[0001] The present invention relates to the field of vacuum handling.

[0002] The invention relates more particularly to a gripping device for a container vacuum, and a vacuum gripping device comprising such a box.

[0003] BACKGROUND OF THE INVENTION

[0004] Vacuum gripping devices are used in many industrial sectors (automotive, pharmaceutical, etc.), for example, to move or manipulate parts in a production line. They generally comprise a vacuum chamber with a bottom panel (commonly called a base) equipped with suction cups. Each suction cup includes a metal body having a first end section fixed in a perforation in the plate and a second end section extending outside the plate and carrying a deformable rubber skirt. The suction cups are designed to simultaneously grip a part when the air inside the chamber is drawn out by means of a vacuum generator.

[0005] Each specific gripping application has its own constraints. Indeed, the parts that such containers are likely to handle vary in shape, weight, and size. The containers must therefore be manufactured in such a way as to meet the specific constraints under which they are used.

[0006] For obvious performance reasons, it is undesirable for one of the suction cups not to participate in gripping the part and continue to draw in air while the other suction cups hold the part. Therefore, a container may not be suitable for moving an object smaller than the one for which it was designed.

[0007] Moreover, it may not be necessary to use all the suction cups of the box to move an object lighter than the one for which it was designed.

[0008] SUBJECT OF THE INVENTION

[0009] The invention therefore aims to provide a gripping device for a vacuum chamber that at least partially overcomes the aforementioned drawbacks. Summary of the invention

[0010] For this purpose, according to the invention, a gripping device for a vacuum chamber is proposed, comprising a tubular body which has a first section delimiting a first cavity in which a first hollow piston is mounted to slide, defining with the walls of the first cavity a first chamber of variable volume into which a compressed air conduit opens.

[0011] The first piston is provided, opposite the first chamber, with an extension A tubular extension with a free end section projecting from the first cavity and equipped with a suction cup. The first piston and the tubular extension define a suction channel with one end opening into the suction cup and an opposite end receiving a rod for a sealed sliding connection. The tubular extension includes at least one first suction port to connect the suction channel to a second chamber under negative pressure.

[0012] The first piston is mounted to move in translation relative to the rod between a rest position in which the rod obstructs the first suction orifice and a gripping position in which the rod is withdrawn from the first suction orifice.

[0013] It is thus possible to control each of the gripping organs of a vacuum chamber independently of each other and therefore to adapt the number of gripping organs used for the movement of an object in question.

[0014] In particular, the first piston, the tubular extension and the rod are coaxial.

[0015] In particular, the first piston is returned to its rest position by a first spring.

[0016] In particular, the tubular body includes a compressed air supply channel having one end opening into the first chamber and an opposite end opening outside the tubular body.

[0017] In particular, the tubular body includes at least one second suction port having one end opening into the second chamber and an opposite end opening outside the tubular body.

[0018] According to a particular feature of the invention, the tubular body comprises a second section defining a second cavity in which a second piston is mounted. This second piston, together with the walls of the second cavity, defines a third chamber and a fourth chamber arranged to be connected, respectively, to the compressed air source and to ambient air. The rod is integral with the second piston and, together with said second piston, defines a delivery channel having one end opening into the suction channel and an opposite end opening into the third chamber. The second piston is mounted to move in translation between a rest position in which the rod is recessed from the suction port of the first piston in its rest position, and a disengagement position in which the rod obstructs the suction port.

[0019] In particular, the first piston and the second piston are coaxial.

[0020] In particular, the second piston is returned to its rest position by a second spring.

[0021] The invention also relates to a vacuum chamber equipped with at least one such gripping device.

[0022] The invention further relates to a vacuum gripping device comprising such a box. Brief description of the drawings

[0023] The invention will be better understood in the light of the following description, which is purely illustrative and not limiting, and should be read in conjunction with the accompanying drawings, among which:

[0024] [Fig-1] [Fig.1] is an axial cross-sectional view of a gripping device according to a a particular embodiment of the invention;

[0025] [Fig.2A] [Fig.2A] is an axial cross-sectional view of the device illustrated in [Fig.1], before the object was taken;

[0026] [Fig.2B] [Fig.2B] is a view identical to [Fig.2A], during the capture of the object;

[0027] [Fig.2C] [Fig.2C] is a cross-sectional view identical to [Fig.2A], during removal of the object;

[0028] [Fig.2D] [Fig.2D] is a cross-sectional view identical to [Fig.2A], after the object has been placed. DETAILED DESCRIPTION OF THE INVENTION

[0029] With reference to [Fig.1], a vacuum gripping device, generally designated as 1, comprises a vacuum chamber 10 in which a plurality of vacuum gripping members 20 are mounted (only one of the gripping members 20 is shown).

[0030] The enclosure 10 comprises a lower panel 11, an upper panel 12, and side panels 13 connecting the lower panel 11 to the upper panel 12 to form a sealed enclosure 14. The enclosure 14 is rectangular in shape and is intended to be connected to a vacuum generation source (not shown).

[0031] The lower panel 11 and the upper panel 12 respectively include first orifices 11.1 and second orifices 12.1 for receiving the gripping members 20. The first orifices 11.1 and the second orifices 12.1 are circular in shape, each of the second orifices 12.1 extending here coaxially opposite one of the first orifices 11.1. The first orifices 11.1 have a diameter greater than that of the second orifices 12.1.

[0032] Each of the gripping members 20 comprises a tubular body 21 having a central axis X substantially perpendicular to the lower panel 11 and the upper panel 12. The tubular body 21 is generally cylindrical in shape and externally comprises a shoulder 21.3 delimiting a first section 21.1 and a second section 21.2 of said tubular body 21. The first section 21.1 and the second section 21.2 are received by fit respectively in one of the first ports 11.1 and in the corresponding second orifice 12.1. The shoulder 21.3 is in watertight contact with an inner face of the upper panel 12.

[0033] The first section 21.1 extends inside the box 10 and includes a first bore 22.1 opening onto a free end of the first section 21.1. The second section 21.2 extends outside the box 10, projecting from an external face of the upper panel 12, and includes a second bore 22.2 opening onto a free end of the second section 21.2. The first bore 22.1 and the second bore 22.2 extend along the X axis and are coaxial.

[0034] The tubular body 21 also includes a third bore 22.3, coaxial with the first bore 22.1 and the second bore 22.2, connecting a bottom of said first bore 22.1 to a bottom of the second bore 22.2.

[0035] The free end of the first section 21.1 receives a retaining plate 23 in position of said first section 21.1 in the housing 10. The retaining plate 23 and the first bore 22.1 together define a first cavity inside which a first piston 24 is mounted to slide along the axis X. The first piston 24 defines, with the walls of the first cavity, a first chamber Ci and a fourth chamber C2, both of variable volume.

[0036] The first section 21.1 includes suction ports 21.4 having one end opening into the second chamber C2 and an opposite end opening into the box 10. The suction ports 21.4 are here symmetrically and equitably distributed around the X axis, in the same plane perpendicular to the X axis.

[0037] The tubular body 20 also includes a supply channel 21.5 for the first chamber Ci with compressed air. The supply channel 21.5 extends along an axis substantially parallel to the X axis, and includes one end opening into the first chamber Ci and an opposite end opening into a first compressed air supply port 27.1 provided in the plate 27. The first supply port 27.1 has one end opening into the supply channel 21.5 and an opposite end intended to be selectively connected to the compressed air source S via a first solenoid valve Vi controlled, for example, by a PLC or an electronic board (not shown).

[0038] The first piston 24 is hollow and is provided with a tubular extension 25 extending along the X-axis from a lower face of the first piston 24 and passing through a circular opening 23.1 in the retaining plate 23, such that a free end section of the tubular extension 25 extends outside the housing 10, projecting from an external face of the lower panel 11. The first piston 24 and the tubular extension 25 define a suction channel 25.1 extending along the X-axis. The suction channel 25.1 has one end connected to a suction cup 26 which is fixed to the free end section of the extension. tubular 25 via an insert 26.1.

[0039] The tubular extension 25 includes suction ports 25.2 having one end opening into the suction channel 25.1 and an opposite end opening into the second chamber C2. The suction ports 25.2 are here symmetrically and equally distributed around the X axis, in a plane perpendicular to the X axis.

[0040] The free end of the second section 21.2 receives a connection plate 27 for a blowing device. The plate 27 and the second bore 22.2 together define a second cavity inside which a second piston 28 is mounted to slide along the X-axis. The second piston 28, together with the walls of the second cavity, defines a third chamber C3 and a fourth chamber C4, both of variable volume.

[0041] The plate 27 includes a second compressed air supply port 27.2 having one end opening into the third chamber C3 and an opposite end intended to be selectively connected to a compressed air source S via a second solenoid valve V2 controlled by the PLC or the electronic board (not shown). The second section 21.2 includes a vent port 21.6 having one end opening into the fourth chamber C4 and an opposite end opening to the outside of the housing 10.

[0042] The second piston 28 is provided with a rod 29 which extends along the axis X, from a lower face of the second piston 28, and which passes through the third bore 22.3 in a sealed manner so that a free end section of the rod 29 extends into the first bore 22.1. The free end section of the rod 29 is received by sliding sealed movement in the suction channel 25.1 delimited by the first piston 24 and the tubular extension 25.

[0043] The rod 29 is hollow and, together with the second piston 28, defines a compressed air channel 29.1 having one end opening into the suction channel 25.1 and an opposite end opening into the third chamber C3 via a compressed air inlet 28.1 provided on an upper face of the second piston 28. It should be noted that the inlet 28.1 has a diameter smaller than that of the second feed 27.2 of the plate 27, which is itself smaller than that of the rod 29.1 inlet channel. In fact, as long as one of the inlet 28.1 and the inlet channel 29.1 has a diameter smaller than that of the second feed 27.2, the diameter of the other of the inlet 28.1 and of the routing channel 29.1 is of little importance (the diameter of the routing orifice 28.1 can be equal to that of the routing channel 29.1).

[0044] The first piston 24 is mounted to slide between a high position, referred to as the rest position, in which an upper face of the first piston 24 is close to the bottom of the first bore 22.1 (Figures 1, 2A, and 2D), and a lower, so-called gripping position in which the upper face of the first piston 24 is away from the bottom of the first bore 22.1 (Figures 2B and 2C). The first piston 24 is returned to the upper position by a first helical spring Ri surrounding the tubular extension 25. The first spring Ri has one end bearing against an inner face of the retaining plate 23 and the lower face of the first spring Rb

[0045] The second piston 28 is mounted to slide between a raised, or rest, position in which the upper face of the second piston 28 is in contact with a lower face of the plate 27 (Figures 1, 2A, 2B and 2D), and a lower, or retraction, position in which the upper face of the second piston 28 is away from the plate 27 ([Fig. 2C]). The second piston 28 is returned to the raised position by a second helical spring R2 surrounding the rod 29. The second spring R2 has one end bearing against the bottom of the second bore 22.2 and the opposite end bearing against the lower face of the second piston 28.

[0046] The free end section of the rod 29 is arranged such that: - when the first piston 24 and the second piston 28 are both in the raised position (Figures 1, 2A and 2D) or in the lowered position ([Fig. 2C]), the end section of the rod 29 completely obstructs the suction ports 25.2 of the tubular extension 25 so that the suction cup 26 is not in fluidic communication with the housing 10; and - when the first piston 24 is in the lower position and the second piston 28 is in the upper position ([Fig.2B]), the end section of the rod 29 is recessed from the suction ports 25.2 so that the suction cup 26 is in fluidic communication with the box 10.

[0047] The operation of the grasping organ 20 will now be detailed with regard to figures 2A to 2D.

[0048] While the first solenoid valve Vi and the second solenoid valve V2 are in the closed state, the housing 10 carrying the gripping member 20 is brought above an object P to be moved, for example via a robotic handling arm (not shown), so that the suction cup 26 of the gripping member 20 is spaced from the object P by a distance slightly less than the stroke of the first piston 24 ([Fig.2A]).

[0049] The first solenoid valve Vj is then moved from the closed state to the open state so that compressed air is blown into the first chamber Ch, which has the effect of moving the first piston 24 from the upper position to the lower position ([Fig. 2B]). The suction cup 26 is then supported against an upper surface of the object P and is now in fluidic communication with the vacuum chamber 10, the end section of the rod 29 no longer obstructing the suction ports 25.2 of the tubular extension 25. It is understood that the suction cup 26 exerts a suction force on the upper surface of object P, which generates a vacuum grip on object P via said suction cup 26.

[0050] It should also be noted that it is possible to measure the vacuum at the level of the second orifice 27.2 supplying the plate 27, this measurement being representative of the suction force exerted by the suction cup 26.

[0051] While the first solenoid valve Vj is held in the open position, the chamber 10 is brought via the robotic arm above the support on which the object P is to be placed, so that the object P is separated from the support by a distance less than a predetermined distance. The second solenoid valve V2 is then brought from the closed position to the open position so that compressed air is blown into the third chamber C3, which has the effect of moving the second piston 28 from the upper position to the lower position ([Fig. 2C]). The end section of the rod 29 then completely obstructs the suction ports 25.2 of the tubular extension 25, and the compressed air blown into the third chamber C3 via the second supply port 27.2 passes through the delivery channel 29.1 and enters the suction cup 26.It is then understood that the object P is blown away and will thus fall by gravity onto the support, the suction cup 26 no longer exerting any suction force on the object P.

[0052] Once the object P is placed on the support, the robotic arm performs a retraction movement, moving the suction cup 26 away from the object P. While the second solenoid valve V2 is held in the open position, the first solenoid valve Vj is brought from the open to the closed position so that, under the action of the first spring Ri and the second spring R2, the first piston 24 and the second piston 28 move substantially simultaneously from the lower to the upper position. The second solenoid valve V2 is then brought from the open to the closed position, the gripping member 20 being ready again for a new vacuum gripping operation.

[0053] It should be noted that: - the different gripping devices 20 carried by the casing 10 can be controlled independently of each other, which makes it possible to use only part of the gripping devices 20 to move an object (in particular depending on the dimensions of the object P, its size, its weight...); - the passage of the first piston 24 from the high position to the low position prevents the suction cups 26 of the unused gripping devices 20 from coming into contact with the object P to be manipulated; - the movement of the second piston 28 from the upper position to the lower position allows for the selective and asynchronous deposit of objects P; and - The first spring Ri and the second spring R2 respectively ensure the upward movement of the first piston 24 and the second piston 28 while maintaining the supply of compressed air in the suction cup 26 in order to limit the risk of self-aspiration by the suction cup 26 when the robotic arm cannot ensure a withdrawal movement after the placement of the object P.

[0054] Of course, the invention is not limited to the embodiments described but encompasses any variant falling within the scope of the invention as defined by the claims.

[0055] The housing 10 may only carry a single gripping member 20.

[0056] The first solenoid valve Vj and the second solenoid valve V2 can be replaced by any device allowing the first supply port 27.1 and the second supply port 23.2 to be selectively connected to the compressed air source S.

[0057] The first supply port 27.1 and the second supply port 27.2 of the plate 27 can be connected to separate compressed air sources.

[0058] The second piston 28 is optional. The rod 29 is then fixed relative to the tubular body 20, and the object P is deposited solely by gravity once the suction cup 26 is no longer in fluidic communication with the vacuum chamber 10, that is, when the first solenoid valve Vj is brought from the open to the closed state. If it is necessary to inject compressed air into the suction cup 26 to deposit the object P, a reversing valve can be mounted on the vacuum generator connected to the chamber 10 to alternate between vacuum and pressure in the enclosure 14 of said chamber 10.

[0059] A check valve can be added to the second piston 28 in order to prevent compressed air from entering the enclosure 14 of the housing 10 when the second solenoid valve V2 changes from the closed state to the open state.

Claims

Claims

1. Gripping member (20) for a vacuum chamber, comprising a tubular body (21) which comprises a first section (21.1) delimiting a first cavity in which is slidably mounted a first hollow piston (24) defining with walls of the first cavity a first chamber (Ci) of variable volume into which a compressed air conduit (S) opens, the first piston being provided, opposite the first chamber, with a tubular extension (25) having a free end section projecting from the first cavity and provided with a suction cup, the first piston and the tubular extension defining a suction channel (25.1) having one end which opens into the suction cup (26) and an opposite end which receives a rod (29) in a sealed sliding manner, the tubular extension comprising at least one first suction orifice (25.2) to connect the suction channel to a second chamber (C2) under vacuum, and the first piston being mounted to move in translation relative to the rod between a rest position in which the rod obstructs the first suction orifice and a gripping position in which the rod is set back from the first suction orifice.

2. A gripping member (20) according to claim 2, wherein the first piston (24), the tubular extension (25) and the rod (29) are coaxial.

3. Gripping member (20) according to any one of the preceding claims, in which the first piston (24) is returned to its rest position by a first spring (Ri).

4. Gripping member (20) according to any one of the preceding claims, in which the tubular body (21) comprises a compressed air supply channel (21.5) having one end opening into the first chamber (Ci) and an opposite end opening outside the tubular body (21).

5. Gripping member (20) according to any one of the preceding claims, wherein the tubular body (21) comprises at least one second suction orifice (21.4) having one end opening into the second chamber (C2) and an opposite end opening outside the tubular body (21).

6. A gripping member (20) according to any one of the claims previous, in which the tubular body comprises a second section (21.2) delimiting a second cavity in which is mounted a second piston (28) defining with walls of the second cavity a third chamber (C3) and a fourth chamber (C4) arranged to be connected respectively to the compressed air source (S) and to the ambient air, the rod being integral with the second piston and defining with said second piston a conveying channel (29.1) having one end opening into the suction channel (25.1) and an opposite end opening into the third chamber (C3), and the second piston being mounted movable in translation between a rest position in which the rod is set back from the suction orifice of the first piston in the rest position, and a deposited position in which the rod obstructs the suction orifice.

7. A gripping member (20) according to claim 6, wherein the first piston (24) and the second piston (28) are coaxial.

8. Gripping member (20) according to claim 6 or 7, in which the second piston (28) is returned to its rest position by a second spring (R2).

9. Vacuum box (10) equipped with at least one gripping member (20) according to any one of the preceding claims.

10. A vacuum gripping device (1) comprising a box (10) according to claim 9.

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