JP7477240B2 - Planar suction gripper - Google Patents

Description

The present invention relates to a surface suction gripper for suctioning and fixing an article according to the preamble of claim 1.

Such areal suction grippers are used in particular for handling large-area objects or for receiving and fixing several objects arranged side by side. They have a planar suction surface with a number of suction points and extend in the shape of a surface. To compensate for unevenness of the object to be acted upon and to ensure a secure fixation, the suction surface can be covered with an elastic covering, in particular a foam covering. To improve the suction properties, the foam covering can be provided with a cover sheet layer made of a different material on the side facing the object to be gripped. Patent document 1 describes, for example, a areal suction gripper in which the cover sheet layer is made of a material with a lower air permeability than the foam covering, whereby a better suction effect can be obtained in the area of the suction points.

Handling electrostatically sensitive items (ESD-sensitive items) poses special demands. Problems can arise, for example, because the base member of the planar suction gripper is electrically insulated from the item by a sealing foam, and potential differences can arise, for example due to electrostatic charging, which can lead to spark discharges. Further challenges arise when handling items with touch-sensitive surfaces and/or handling processes with high cleanliness requirements. Such problems arise, for example, when handling thin glass sheets or circuit boards, which have electronic functional elements, such as circuit boards or displays.

EP1916206B1

The objective of the present invention is to improve the usability of surface suction grippers for sensitive objects such as those described above.

The above problem is solved by a planar suction gripper according to claim 1. The planar suction gripper has a base member with a particularly flat handling side facing the object for suctioning the object. The handling side has a number of suction sections through which ambient air is sucked in for suctioning the object. The handling side is covered with an elastically deformable covering material, in particular a foam covering material. The side of the elastically deformable covering material facing the object has a cover sheet layer, which comes into contact with the object when suctioning the object.

In this case, the cover sheet layer is formed in multiple layers, in particular in two layers, and comprises a conductive contact layer and an adhesive layer, which is used to attach the conductive contact layer to the elastically deformable covering material (in particular a foam covering material). In this case, the cover sheet layer is attached to the elastically deformable covering material so that the conductive contact layer faces the article, i.e., when the article is attracted, the contact layer touches the article, in particular abuts against the article. In this sense, the conductive contact layer forms the actual handling surface of the planar suction gripper.

The elastically deformable covering is in particular attached to the housing bottom of the base member. The housing bottom itself may be hard, and the elastically deformable covering can compensate for possible unevenness on the surface of the article when pressed against the article, for example the elastically deformable covering is locally compressed by the pressing force. The cover sheet layer is in particular also formed elastically deformable, so that the composite of the covering and the cover sheet layer can also compensate for unevenness on the surface of the adsorbed article.

The cover sheet layer prevents the accumulation of contaminating substances in the material of the elastically deformable covering (especially foam-like coverings) that could cause undesirable impressions during the gripping process. Meanwhile, the conductive form of the contact layer allows for a controlled release of charge, thereby avoiding damage due to electrostatic discharge events.

Furthermore, as will be explained in more detail below, the multi-layer structure of the cover sheet layers allows them to be replaced if necessary. This makes it possible, in particular, to replace the cover sheet layers for maintenance purposes and/or for equipment modifications to suit different applications. Replacement of the cover sheet layers can also be advantageous in order to meet particularly high cleaning requirements. Overall, constructional waste is reduced in the assembly and operation of the surface suction gripper.

In particular, the elastically deformable covering has a number of passage holes and the cover sheet layer has a number of, in particular, regularly arranged, perforations. In this case, in particular the surface density of the perforations in the cover sheet layer is higher than the surface density of the passage holes in the elastically deformable covering. In other words, in particular the average number of perforations per unit area in the cover sheet layer is higher than the average number of passage holes per unit area in the covering, so that the perforations in the cover sheet layer are on average closer to one another than the passage holes in the covering. In this sense, the perforations in the cover sheet layer are arranged more densely, so that the cover sheet layer does not have to be positioned exactly relative to the passage holes in the covering. As will be explained in more detail below, this facilitates the assembly of the surface suction gripper, in particular when the cover sheet layer is designed to be replaceable.

In particular, it is provided that the passage holes in the covering are assigned to each suction part or at least to each group of suction parts. In particular, the base part comprises a housing having a housing bottom and a number of suction openings, each passage hole being aligned with one suction opening or one group of suction openings.

In particular, the cover sheet layer is formed in the form of a perforated film, in particular with a regular, matrix-like arrangement of perforations. For example, the cover sheet layer may be formed in the form of a mesh or in the form of a hole lattice.

In yet another embodiment, the cover sheet layer is formed as a replacement film. This can be achieved, for example, by the adhesive layer being a reappliable adhesive film that is applied and peelable (particularly reappliable). In particular, the adhesive properties are such that the cover sheet layer can be peeled off from the elastically deformable covering material without destruction. In this sense, the cover sheet layer can be replaced without destroying the covering material located underneath the cover sheet layer, which simplifies the adaptation of the surface suction gripper to various applications and the cleaning and maintenance of the surface suction gripper.

The adhesive layer is in particular formed as a double-sided adhesive film, the adhesive coatings on both sides of the adhesive film being selected such that in the laminated state it adheres weaker to the foam than to the contact layer. This makes it possible to peel the entire composite consisting of the contact layer and the adhesive layer from the foam.

In yet another embodiment, the electrically conductive contact layer is formed in the form of a fiber-containing material. In order to generate electrical conductivity, the fibers and/or the interfiber spaces can be provided with corresponding additives. Suitable additives are, for example, ionic compounds or conductive particles. For example, the fibers of the material can be correspondingly coated or impregnated. Furthermore, the fibrous structure of the contact layer can reduce indentations, which are a hindrance when handling smooth surfaces.

The fiber-containing material may be in the form of a structure, for example in the form of a knitted or woven fabric. As a material, for example, polyethylene, especially in woven form, comes into consideration.

The electrically deformable coating material and/or adhesive layer is preferably designed to be electrically insulating. The discharge of the charge is preferably controlled through the contact layer.

As mentioned above, the contact layer allows the discharge of the electric charge. Due to constructional constraints, the discharge resistance is set high, in particular so that only a small discharge current flows. In particular, the conductive contact layer and/or the electrical connection between the contact layer and the assigned discharge contact is formed so that the discharge resistance is 10 ⁶ to 10 ⁹ Ohm. This high discharge resistance is measured in particular from the contact point with the contact layer, which is accessible on the handling side, towards the discharge contact. In particular, the form of the electrical conductivity of the contact layer influences the discharge resistance.

However, it is also conceivable that the discharge resistance is determined by the manner of contact. Such a discharge contact can be a connection contact in the sense of a contact point with the base member. However, the discharge contact can also be formed by the base member itself or by a part of the base member.

During operation of the surface suction gripper, the discharge contact is in particular electrically grounded.

The discharge contacts can be provided in various ways. For example, the base element itself can be made conductive or the contact layer can be electrically connected to the base element, in particular through a (particularly insulating) coating. However, it is also conceivable that the base element consists at least partially, in particular entirely, of an electrically non-conductive insulating material and has a connection contact which is electrically connected to the contact layer. In particular, the connection contact in the base element is surrounded by an electrically insulating material. For example, the connection contact can be provided by a screw which passes through the base element and contacts the contact layer.

An electrical contact connection can also be obtained by the contact layer, or in particular the entire cover sheet layer, having at least one protrusion that extends beyond the handling side and is folded around the electrically deformable covering material or around a part of the base material. In that case, the protrusion can be electrically connected to a discharge contact on the side of the base material. In particular, the protrusion is formed in the form of a tongue that is folded back around the covering material and/or around a part of the base material.

The base member comprises, in particular, a housing having a housing bottom, on which an elastically deformable covering material is arranged, and on which, in particular, a suction portion is also provided.

Such a protrusion is guided around the elastically deformable covering material, for example, so that it rests directly against the housing bottom. In particular, in that case, the connection contact on the base member side is formed so that it comes into contact with a protrusion of the contact layer that is bent along the housing bottom.

The housing bottom may itself be made conductive or may provide the above-mentioned discharge contact by contacting the protruding portion of the contact layer.

However, it is also conceivable that the protruding portion of the conductive contact layer (or cover sheet layer) may be guided to the upper side of the housing and electrically connected there to the discharge contacts.

In one simple embodiment, the cover sheet layer extends over the entire handling side (i.e. covers everything except for possible penetrations). This embodiment allows for easy application to the elastically deformable covering material, since only a precisely cut cover sheet layer needs to be applied to the surface of the elastically deformable covering material.

However, it may also be advantageous to provide a cover sheet layer only in those areas of the handling side which are important for electrostatic discharge, so that the cover sheet layer only covers a partial area of the handling side.

The present invention will be explained in detail below with reference to the drawings.

FIG. 2 is an exploded view for explaining the structure of the planar suction gripper according to the present invention. FIG. 2 is a perspective view showing the handling side of the planar suction gripper shown in FIG. 1; FIG. 2 is a schematic diagram for explaining the structure of a cover sheet layer. FIG. 2 is an exploded view illustrating a possible realization of the discharge contacts of the conductive contact layer. FIG. 5 is a perspective view showing the planar suction gripper according to FIG. 4 . FIG. 11 is a perspective view illustrating another embodiment of the discharge contact of the cover sheet layer.

In the following description and figures, the same or corresponding features are respectively designated by the same reference numerals.

As shown in Figures 1 and 2, the planar suction gripper 10 has a base member 12 and a handling side 14 that is formed particularly flat and is brought into contact with the surface of an object (not shown) to attract the object.

In a typical embodiment of the present invention, the base member 12 has, inter alia, a housing 16 that encloses an inner vacuum chamber and has a housing bottom 18 facing the handling side 14.

The base element may be formed, for example, as a hollow profile, for example an extruded profile, made of a suitable extruded material, for example aluminum, which is closed, in particular at the end, by a terminal cap 20 in order to form an inner suction chamber.

An elastically deformable covering material 22 is arranged on the housing bottom 18. The elastically deformable covering material 22 is particularly determined so as to cover the entire housing bottom 18. The elastically deformable covering material is, for example, a foam covering material.

The handling side 14 has a number of suction areas 24. In the illustrated example (see Figs. 1 and 2), these are defined by the elastically deformable covering 22 having a number of passage holes 26 which correspond to suction openings, not shown in detail, in the housing bottom 18. For reasons of clarity, only a few suction areas 24 are shown on the handling side 14 in Fig. 2. The suction areas are arranged as a whole over the entire housing bottom 18, in particular in a matrix-like distribution.

The surface of the elastically deformable covering material 22 facing away from the base member 12 is provided with a cover sheet layer 28. The cover sheet layer 28 may, for example, completely cover the side of the elastically deformable covering material 22 facing away from the base member 12 (see Figures 1 and 2).

The cover sheet layer 28 is particularly formed in multiple layers. Figure 3 shows a schematic diagram for explaining the structure of the cover sheet layer 28 and its attachment to the elastically deformable covering material 22.

In particular, the cover sheet layer 28 is a two-layer structure having a conductive contact layer 30 and an adhesive layer 32 used to attach the conductive contact layer 30 to the elastically deformable covering material 22. The cover sheet layer 28 is attached to the elastically deformable covering material 22 so that the conductive contact layer 30 contacts the adsorbed article and thus forms the actual handling surface 34 of the planar suction gripper 10.

The adhesive layer 32 is formed in particular as a two-sided adhesive film with a substrate film 36 that is provided with an adhesive coating on both sides. In particular, the adhesive coating in the direction of the conductive contact layer 30 is formed in such a way that it has a higher adhesion than the adhesive layer on the opposite side.

Before the two cover sheet layers 28 are applied to the elastically deformable covering material 22, the cover sheet layers may be provided as a three-layer starting material (see FIG. 3). This facilitates storage and transport. For this purpose, in particular the side of the substrate film 36 facing away from the conductive contact layer is provided with a protective film 38. The protective film 38 is in particular formed so that it can be easily peeled off from the substrate film 36 and leaves the adhesive coating of the substrate film 36 exposed. In particular the side of the protective film 38 facing the substrate film 36 may be provided with a silicone coating to facilitate peeling. After peeling off the protective film 38, the composite of the conductive contact layer 30 and the adhesive layer 32 can be applied to the surface of the elastically deformable covering material 22 facing away from the base member 12.

3, the conductive contact layer 30, and in particular the adhesive layer 32, also have a number of through-holes 40 (see the enlarged view in FIG. 3). The through-holes 40 are arranged regularly, in particular in a matrix, with a density per unit area that is much greater than the surface density of the passage holes 26 in the elastically deformable covering material 22. This provides, among other things, the advantage that precise positioning of the cover sheet layer 28 on the elastically deformable covering material 22 is not necessary.

Several possibilities for electrical contact of the conductive contact layer 30 are described with reference to Figures 4 to 6.

The cover sheet layer 28, and in particular the conductive contact layer 30, has a protrusion 42 extending beyond the handling surface 34. In that case, the protrusion 42 may be folded around the elastically deformable covering material 22 so as to be located between the elastically deformable covering material 22 and the housing bottom 18, in particular so that the conductive contact layer 30 touches the housing bottom 18.

To provide a discharge contact 44 (FIG. 5) on the base member side, for example, a contact pin 46 (e.g., a screw) may be inserted from the upper side of the housing 16 through the base member 12 to the protrusion 42.

If the housing 16 itself consists of a non-conductive material, the contact pin 46 forms a connection contact 48 that is intended to discharge the charge taken up by the conductive contact layer 30. However, it is also conceivable that the contact pin 46 creates a connection to a part of the housing 16 that is itself made conductive, for example to a groove 50 on the front side of the housing, in which case a corresponding ground contact can be attached.

Figure 6 shows the possibility of a corresponding protrusion 42 of the cover sheet layer 28 or the conductive contact layer 30 being folded around the elastically deformable covering material 22 and around the side surface 52 of the housing 16 and connected to a discharge contact 44 on the upper side 54 of the housing 16. For this purpose, for example, a contact pin 46 may pass through the protrusion 42 and engage in a corresponding groove 50 on the upper side 54.

For example, it is conceivable that the cover sheet layer 28 does not cover the entire handling surface 34, but only a portion of it, such as the area of the protrusion 42. However, it may also be advantageous if the entire handling side 14 is covered with the cover sheet layer 28.

10 Planar suction gripper 12 Base member 14 Handling side 16 Housing 18 Housing bottom 20 End cap 22 Covering material 24 Suction portion 26 Passage hole 28 Cover sheet layer 30 Conductive contact layer 32 Adhesive layer 34 Handling surface 36 Substrate film 38 Protective film 40 Through portion 42 Protruding portion 44 Discharge contact 46 Contact pin 48 Connection contact 50 Groove 52 Side surface 54 Upper side

Claims (14)

A planar suction gripper (10) for suctioning and fixing an article by negative pressure, comprising a base member (12) having a handling side (14) for the article, the handling side (14) having a plurality of suction sections (24) to which negative pressure can be applied in order to suction the article, the handling side (14) having an elastically deformable covering material (22) and a cover sheet layer (28) arranged on a side of the elastically deformable covering material (22) facing away from the base member (12),
the cover sheet layer (28) is multi-layered and has a conductive contact layer (30) and an adhesive layer (32) for attaching the contact layer (30) to the elastically deformable covering material (22), the conductive contact layer (30) being arranged to abut against the article when the article is fixed, the conductive contact layer (30) having at least one protrusion (42) that extends beyond the handling side (14), the protrusion being guided around the elastically deformable covering material (22) and/or around a portion (52) of the base member (12) and electrically connected to a discharge contact (44) on the base member side. The planar suction gripper (10) according to claim 1, characterized in that the elastically deformable covering material (22) has a plurality of passage holes (26), the cover sheet layer (28) has a plurality of regularly arranged penetrations (40), and the number of the penetrations (40) provided in the cover sheet layer (28) per unit area is greater than the number of passage holes (26) in the elastically deformable covering material (22). The planar suction gripper according to claim 1, wherein the cover sheet layer (28) is formed in a mesh shape with a plurality of regularly arranged through-holes (40). The surface suction gripper (10) according to any one of claims 1 to 3, wherein the adhesive layer (32) is formed to be adhesive and removable again, so that the cover sheet layer (28) can be peeled off from the elastically deformable covering material (22) in a non-destructive manner. The surface suction gripper (10) according to any one of claims 1 to 4, wherein the adhesive layer (32) is formed as a double-sided adhesive film and comprises a substrate film (36) having an adhesive coating on both sides, the adhesive coating facing the elastically deformable covering material (22) having a smaller adhesion force when in an adhesive state than the adhesive coating facing the contact layer (30). The planar suction gripper (10) according to any one of claims 1 to 5, wherein the conductive contact layer (30) comprises a fiber-containing material having an additive for achieving electrical conductivity. The planar suction gripper (10) according to any one of claims 1 to 6, wherein the elastically deformable covering material (22) and/or the adhesive layer (32) are formed to be electrically insulating. The surface suction gripper (10) according to any one of claims 1 to 7, wherein the conductive contact layer (30) and/or the electrical connection between the contact layer (30) and the discharge contact (44) are formed so as to have a discharge resistance of 10 ⁶ to 10 ⁹ Ohm. The surface suction gripper (10) according to any one of claims 1 to 8, wherein the base member (12) is formed to be conductive, and the contact layer (30) is electrically connected to the base member (12). The surface suction gripper (10) according to any one of claims 1 to 8, wherein the base member (12) is at least partially made of a non-conductive material and has a connection contact (48) electrically connected to the contact layer (30). The surface suction gripper (10) according to any one of claims 1 to 10, wherein the base member (12) comprises a housing (16) having a housing bottom (18), the elastically deformable covering material (22) is disposed on the housing bottom, and the protrusion (42) of the conductive contact layer (30) abuts against the housing bottom (18). The surface suction gripper (10) according to any one of claims 1 to 10, wherein the base member (12) comprises a housing (16) having a housing bottom (18) on which the elastically deformable covering material (22) is arranged, and the protrusion (42) of the conductive contact layer (30) is led to an upper side (54) of the housing (16) away from the covering material (22) and connected there to the discharge contact (44). A surface-shaped suction gripper (10) according to any one of claims 1 to 12, wherein the cover sheet layer (28) covers the entire surface of the elastically deformable covering material (22) facing the handling side (14). The surface-shaped suction gripper (10) according to any one of claims 1 to 12, wherein the cover sheet layer (28) covers only a portion of the surface of the elastically deformable covering material (22) facing the handling side (14).