A device for holding an object

Abstract

The object of the present invention is to further improve the devices belonging to this field so that they have even lower energy consumption. [Solution] The present invention relates to a device for holding an object, the device having an annular molded cushion (2), and this annular molded cushion is Contains granular material (4), Surrounding the suction chamber (6) which is open to at least one side, The molded cushion (2) and the suction chamber (6) have connection parts (12, 26) for a negative pressure source. This device is characterized in that at least one annular seal lip (32) is arranged on the molded cushion (2), preferably at least two annular seal lips (32).

Description

Technical Field

[0001] The present invention relates to a device for holding an object, the device having an annular shaped cushion, the annular shaped cushion containing particulate matter and enclosing a suction chamber that opens towards at least one side, wherein the shaped cushion and the suction chamber have a connection part for a negative pressure source.

Background Art

[0002] Devices of this type are known from the prior art and are used for holding, handling and / or transporting objects. When an object is to be held by this device, the shaped cushion is brought into contact with the object. The shaped cushion is made of a flexible and / or elastic material and thus deforms under the pressure exerted on the shaped cushion by the object. Thereby, the particulate matter inside the shaped cushion moves. Subsequently, a negative pressure is applied to the shaped cushion. At this time, the negative pressure originates from a negative pressure source such as a pump, which may for example be part of the device but does not have to be part of the device. Devices of this type are often used in manufacturing plants as end effectors for robots, which may be connected to a central negative pressure supply or have a pump on their own. By applying negative pressure to the shaped cushion, air is sucked out of the shaped cushion, and the shaped cushion hardens at the position created by contact with the workpiece to be gripped. In this way, the device adapts well to the outer shape, geometry and / or configuration of the object.

[0003] These types of devices initially had molded cushions with large-area end faces, which preferably made full contact with the object to be held in order to deform the molded cushion. One development of this type of device has an annular molded cushion. The annular molded cushion may be configured in an annular shape, but this is not an essential embodiment. Annular means that the cross-section of the molded cushion has a closed outer contour and a closed inner contour. The outer contour is formed, for example, by an outer wall, and the inner contour is formed by an inner wall. Between the inner and outer walls is a volume containing granular material. On one side, the molded cushion is attached to a retainer that serves to assemble the device to other components, such as a robotic arm. On the opposite side, the molded cushion is separated by an end face. Typically, the end face is provided to make contact with the object to be held.

[0004] Inside the inner wall is a suction chamber surrounded by a molded cushion, which is then separated by the inner wall of the cushion. The suction chamber has a connection for a negative pressure source. This connection is located on the side of the suction chamber facing the device's holding section. On the opposite side, facing the object to be held, the suction chamber is open.

[0005] When an object is held, the negative pressure applied to the molded cushion acts to harden it, thereby maintaining its conformed shape to the object. The negative pressure applied to the suction chamber exerts an attractive force on the object to be held. This force holds the object in place within the device.

[0006] The characteristics and constituent requirements described above are not only preferable to those present in devices based on the prior art, but are also preferable to those based on embodiments of the present invention.

[0007] A drawback is that this type of device must exert a strong suction force to securely hold the object to be held. This can be achieved, for example, by a pump, but such a pump must operate continuously to maintain the required suction force for the duration of the holding period. This results in high energy consumption and consequently, relatively high costs. [Overview of the Initiative]

[0008] Therefore, the object of the present invention is to further improve the devices belonging to this field so that even lower energy consumption is required.

[0009] The present invention solves the problem by having an apparatus having the constituent elements of the premise of claim 1, characterized in that at least one annular seal lip is arranged on the molded cushion, preferably at least two annular seal lips.

[0010] The fundamental finding of this invention is that the high energy consumption of prior art devices is at least partly due to the fact that, when negative pressure is applied to the molded cushion, the contact between the molded cushion and the object to be held is not adequately sealed, even though the molded cushion is almost perfectly conformed to the contour, shape, and form. This insufficient sealing allows air to flow into the suction chamber where negative pressure is applied, resulting in a pressure drop. Such a pressure drop means that the pressure difference between the negative pressure provided by the negative pressure source and the ambient pressure decreases. In other words, the strength of the negative pressure inside the suction chamber decreases, and the pressure inside the suction chamber increases. Such leakage is reduced or even completely avoided by the seal lip according to the present invention, thereby making it easier and, consequently, easier to maintain the pressure difference between the pressure inside the suction chamber and the ambient pressure necessary to hold the object, and at a lower energy cost.

[0011] The seal lip is configured in an annular shape. This can mean an annular shape, but is not mandatory. Any closed contour or path on which the seal lip extends is considered an annular shape in the sense of this invention.

[0012] The molded cushion preferably has an inner wall facing the suction chamber, an outer wall facing away from the suction chamber, and an end face connecting the inner wall to the outer wall, with the seal lip positioned on the end face. The end face usually faces the object to be held. The annular seal lip preferably extends to surround the opening leading to the suction chamber.

[0013] In a preferred embodiment, the seal lip is integrally formed with the molded cushion. The molded cushion having the seal lip can be, for example, cast, in which case the form of the molded cushion and the form of the seal lip are present in the mold and cast.

[0014] Alternatively, the seal lip may be attached to the molded cushion, for example, by bonding, welding, or other means. In this case, to avoid the leaks described above, it is preferable that the bond between the seal lip and the molded cushion is as airtight as possible along the entire extension of the seal lip.

[0015] The end face of the molded cushion has a ring shape. This may be an annular shape; however, this is not mandatory. What is important is that the end face forms an opening that forms an inlet to the suction chamber. The ring formed by the end face has a width corresponding to the distance between the inner wall and the outer wall. This width is preferably constant along the circumference. The end face has a radially inner portion and a radially outer portion. The radially inner portion is preferably half, one-third, or one-quarter of the radially inner portion of the end face. The radially inner portion of the end face is the portion of the end face that is in contact with the edge leading to the inner wall. The radially outer portion is preferably half, one-third, or one-quarter of the radially outer portion of the end face. The radially outer portion of the end face is the portion of the end face that is in contact with the edge leading to the outer wall.

[0016] The seal lip is preferably positioned on the radially inward portion of the end face. This has the advantage of positioning the seal lip near a suction chamber to which negative pressure is applied, which needs to be sealed to the surroundings. Furthermore, this arrangement allows the use of a relatively long seal lip without it protruding radially outward from the molded cushion.

[0017] In a preferred embodiment, the seal lip does not protrude radially outward from the molded cushion.

[0018] The seal lip preferably has a first section that curves away from the molded cushion. The seal lip further has a second section that curves towards the molded cushion. In this way, the seal lip can act as a spacer between the end face of the molded cushion and the object to be held, thereby applying the negative pressure applied to the suction chamber to the seal lip as well.

[0019] It has been found to be preferable that negative pressure can be applied to the molded cushion and the suction chamber independently of each other.

[0020] The molded cushion and the suction chamber preferably have a common connection for a negative pressure source, and the device preferably has a valve that can distribute negative pressure to the molded cushion and / or the suction chamber. In this case, the device has only one connection to which a negative pressure source can be placed, and when the negative pressure source is connected to the connection, negative pressure can be applied to either the molded cushion or the suction chamber through it. From the connection, a partial pipe leading to the molded cushion and another partial pipe leading to the suction chamber extend. Both of these partial pipes are portions of a common pipe that begins at the connection. A valve is preferably located at the branching point. This valve is preferably set up to supply negative pressure to either the molded cushion or the suction chamber only. In addition, the valve is preferably set up to supply negative pressure to both the molded cushion and the suction chamber, and it is particularly preferable that the valve can supply negative pressure to the molded cushion and the suction chamber with different strengths. This can be achieved, for example, by the valve varying the flow resistance in the partial pipe leading to the molded cushion and the flow resistance in the partial pipe leading to the suction chamber. This can be achieved, for example, by one or more throttle valves.

[0021] A method for holding an object, utilizing an apparatus based on an embodiment of the present invention, is also an independent invention. In this case, first, a molded cushion is adapted to the geometry, external shape, and / or form of the object to be held. This is preferably done by the molded cushion coming into contact with the object. At this point, no negative pressure is yet applied to the molded cushion. The molded cushion is flexible and deformable, and therefore adapts to the object.

[0022] Under these conditions, negative pressure is applied to the suction chamber. This means that a holding force is exerted on the object even at this early stage, and this holding force can further lead to the molded cushion being adapted to the shape, geometry, and / or form of the object.

[0023] After the molded cushion has deformed in this way, negative pressure is applied to it. As a result, the molded cushion loses its flexibility and hardens in the shape it has formed, as explained above. Furthermore, the negative pressure already applied to the suction chamber prevents the molded cushion from moving relative to the object as it hardens.

[0024] The release of an object from this device is preferably carried out in the reverse order of the above. After the object has been held for a sufficiently long time, first, the negative pressure applied to the suction chamber is removed. To achieve this, it may be sufficient to simply close the valve on the piping that guides the externally applied negative pressure to the suction chamber. Alternatively, the suction chamber can be ventilated, for example, by opening the connection between the suction chamber and the surroundings. This causes pressure equilibrium, and the holding force on the object generated in the suction chamber by the negative pressure can no longer be maintained. Only then, but with a time offset, is it preferable that the negative pressure applied to the molded cushion be removed or that it be further ventilated.

[0025] The suction chamber is preferably covered by an air-permeable cover on the open side. Such a cover allows the suction force and resulting holding force exerted on the object by the negative pressure inside the suction chamber to continue to be applied to the object. In such cases, the expression "suction chamber open to one side" is used here. The air-permeable cover ensures that even very flexible objects are not sucked into the suction chamber, or at least not sucked in as strongly as in the prior art, thereby preventing deformation or damage. The air-permeable cover is preferably made from a flexible but inelastic material. Accordingly, the cover can follow the shape of the molded cushion, which changes during adaptation.

[0026] The air-permeable cover is preferably made from a cloth, and especially preferably from a woven fabric.

[0027] The air-permeable cover is placed on the molded cushion and is preferably bonded and / or welded.

[0028] In a preferred embodiment, the molded cushion preferably has an inner wall facing the suction chamber, an outer wall facing away from the suction chamber, and an end face connecting the inner wall to the outer wall, and the air-permeable cover is arranged at the edge between the inner wall and the end face.

[0029] The air-permeable cover preferably comprises at least one stabilizing strip having a higher rigidity, particularly bending rigidity, than other parts of the air-permeable cover. It is particularly preferred that the at least one stabilizing strip extends from the inner wall of the molded cushion to the inner wall thereof.

[0030] Next, several embodiments of the apparatus for holding an object will be described in detail with reference to the accompanying drawings. The drawings show the following: BRIEF DESCRIPTION OF THE DRAWINGS

[0031] [Figure 1] 1 is a schematic cross-sectional view showing such an apparatus according to a first embodiment. [Figure 2] 2 is a schematic cross-sectional view showing the apparatus of FIG. 1 in contact with an object. [Figure 3] 3 is a schematic cross-sectional view showing such an apparatus according to a second embodiment. [Figure 4] 4 is a schematic cross-sectional view showing such an apparatus according to a third embodiment. [Figure 5] 5 is a schematic cross-sectional view showing the apparatus of FIG. 4 in contact with an object. [Figure 6] 6 is a schematic cross-sectional view showing such an apparatus according to a fourth embodiment. DETAILED DESCRIPTION OF EMBODIMENTS FOR CARRYING OUT THE INVENTION

[0032] Figure 1 shows a schematic cross-sectional view of an object-holding device. The device has an annular molded cushion 2 containing granular material 4. The molded cushion 2 surrounds an annular suction chamber 6 that opens downward in Figure 1. The molded cushion 2 is attached to a connecting component 10 by a coupling member 8. The connecting component 10 is located, for example, on an arm of a robot (not shown). The device has a connection 12 for a negative pressure source on the connecting component 10, through which air can be drawn in from an intermediate space 14 between the connecting component 10 and the coupling member 8 when the connection 12 is connected to a negative pressure source. The coupling member 8 has a passage 16 that connects the intermediate space 14 to the suction chamber 6. Thus, when a negative pressure source connected to the connection 12, such as a pump, applies negative pressure to the connection 12, air is drawn out from the intermediate space 14 and also from the suction chamber 6 through the passage 16.

[0033] In the illustrated embodiment, the connecting component 10 includes two valves 18, which, when opened, connect the intermediate space 14 to the annular sub-chamber 20. The coupling member 8 includes two other through-holes 22, through which the sub-chamber 20 connects to the molded cushion 2. Thus, when the valves 18 are open, air is drawn out of the molded cushion 2 by a negative pressure source located in the connecting component 12, and the granular material 4 is tightly enclosed by the outer covering 24 of the molded cushion 2. The connecting component further includes a second connecting component 26 that can be connected to a negative pressure source. In this way, when the valves 18 are closed, it is possible to apply different negative pressures to the molded cushion 2 and the suction chamber 6, respectively.

[0034] The suction chamber 6 also contains a stopper 28 and a sensor 30, which allow monitoring of the approach to the object to be held. Two sealing lips 32 are positioned on the side of the outer casing 24, shown at the bottom in Figure 1. This seals the contact area between the molded cushion outer casing 24 and the object to be held. This makes it easier to maintain the negative pressure inside the suction chamber 6 that exerts suction force on the object to be held.

[0035] Figure 2 shows the device in Figure 1 in contact with object 34. It can be seen that the seal lip 32 is in contact with object 34. The negative pressure generated inside the suction chamber 6 causes object 34 to be attracted to the molded cushion 2. The negative pressure generated inside the molded cushion causes the outer covering 24 of the molded cushion to be in close contact with the granular material 4, thereby preventing the individual elements of the granular material 4 from moving relative to each other.

[0036] Figure 3 shows a schematic cross-sectional view of the apparatus based on the second embodiment. The seal lip 32 has a thickened end, thereby improving the sealing characteristics. The seal lip 32 is part of the central seal member 36, which separates the suction chamber 6 toward the connecting part 10 instead of the central portion of the coupling member 8. The connecting part 12 is connected to the suction chamber 6 via piping 38.

[0037] A third embodiment of the object-holding device, shown in a schematic cross-sectional view in Figure 4, is substantially equivalent to the drawing in Figure 1. However, the device shown in Figure 4 does not have a seal lip 32. This device is configured to be air-permeable and includes a cover 40 that separates the suction chamber 6 downwards, i.e., toward the object to be held. Because the cover 40 is air-permeable, the negative pressure generated in the suction chamber by a negative pressure source (not shown) located at the connection 12 exerts a holding force on the object. The drawings in Figures 5 and 6 correspond to those in Figures 2 and 3. However, the embodiments of the device shown in Figures 5 and 6 do not have a seal lip 32. These embodiments each include an air-permeable cover. [Explanation of Symbols]

[0038] 2 Molded cushions 4 Particulate matter 6 Suction chamber 8 Connecting member 10 connecting parts 12 Connection part 14 Intermediate space 16 Passage section 18 valves 20 Antechamber 22 Penetration section 24 Outer cover 26 Second connection section 28 Stopper 30 sensors 32 Seal Lip 34 Object 36. Sealing member 38 Piping 40 Cover

Claims

1. A device for holding an object, the device having an annular molded cushion (2), and this annular molded cushion is It contains granular material (4), Surrounding the suction chamber (6) which is open to at least one side, In the apparatus, the molded cushion (2) and the suction chamber (6) have connection parts (12, 26) for a negative pressure source, The apparatus is characterized in that at least one annular seal lip (32) is provided on the molded cushion (2), preferably at least two annular seal lips (32).

2. The apparatus according to claim 1, characterized in that the molded cushion (2) has an inner wall facing the suction chamber (6), an outer wall facing away from the suction chamber (6), and an end face connecting the inner wall to the outer wall, and the seal lip (32) is arranged on the end face.

3. The apparatus according to claim 1 or 2, characterized in that the seal lip (32) is integrally formed with the molded cushion (2).

4. The apparatus according to claim 2 or 3, characterized in that the seal lip (32) is arranged in the radially inward portion of the end face.

5. The apparatus according to any one of claims 1 to 4, characterized in that the seal lip (32) does not protrude radially outward from the molded cushion (2).

6. The apparatus according to any one of claims 1 to 5, characterized in that the seal lip (32) has a first area that curves away from the molded cushion (2) and a second area that curves towards the molded cushion (2).

7. The apparatus according to any one of claims 1 to 6, characterized in that negative pressure can be applied separately to the molded cushion (2) and the suction chamber (6).

8. The apparatus according to any one of claims 1 to 7, characterized in that the molded cushion (2) and the suction chamber (6) have a common connection (12) for a negative pressure source, and the apparatus preferably has a valve (18) which can distribute negative pressure to the molded cushion (2) and / or the suction chamber (6).

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