EP3694691A1

EP3694691A1 - Protective device for an industrial robot, and protective element for such a protective device

Info

Publication number: EP3694691A1
Application number: EP18785920.2A
Authority: EP
Inventors: Theo Doll
Original assignee: Dr Doll Engineering GmbH
Current assignee: Dr Doll Engineering GmbH
Priority date: 2017-10-12
Filing date: 2018-10-09
Publication date: 2020-08-19
Also published as: WO2019072854A1; DE102017218229A1

Abstract

The invention relates to a protective device (1) for an industrial robot (R) comprising at least one protective element, which is provided as a sleeve for an outer wall section (8) of the industrial robot (R), and a sensor system (9), which is paired with the protective element and which is designed such that a collision between the protective element and an obstacle (H) can be detected. The protective element is a molded part (7a-c, 7i, 7j) which is made of plastic and which has a first electrically conductive layer (13a-f) on at least one functional surface, and the sensor system (9) is designed such that a collision-induced change in the electric resistance (Rl) of the conductive layer (13a-f) can be detected.

Description

Protection device for an industrial robot and protective element for such

guard

The invention relates to a protective device for an industrial robot with at least one protective element, which is provided as a shell for an outer wall portion of the industrial robot, and a sensor associated with the protection sensor, which is designed such that a collision between the protective element and an obstacle can be detected.

Such a protective device is known from AT 561 097 B1 and provided as safety equipment for a collaborative industrial robot. As collaborative industrial robots are used in the industrial sector used robots that work with a person in a common workspace, the person is not shielded by physical protection devices such as fences, barriers or the like of the robot. In the absence of such a shield, there is fundamentally a risk of collision between the working person and the robot, for example in the case of an uncoordinated engagement of the person in the pivoting region of the robot. Nevertheless, in order to be able to ensure sufficient working safety, protective devices are required which detect such a collision in order to enable an emergency shutdown of the robot. The known protective device has at least one protective element with a protective cover and a base plate and a sensor element associated with the sensor. The protective cover spans the base plate like a pillow and is essentially gas-tight and elastic. The base plate is intended for attachment to a potentially collision-prone outer wall section of the industrial robot, for example on an articulated arm. Inside the protective element, a pump is provided which is intended to generate a gas overpressure in the protective element. In a collision, the protective cover is elastically deformed. As a result, the gas pressure in the interior of the protective element increases. The sensor technology of the known protective device has a pressure sensor, by means of which such a pressure rise can be detected and converted into a corresponding signal. The signal can be forwarded to a control unit of the robot so that it can be switched off as a function of the signal and serious injuries to the person can be avoided.

The object of the invention is to provide a protective device and a protective element of the type mentioned, which have a simplified structure and at the same time ensure high reliability. This object is achieved for the protective device in that the protective element is a molded part made of plastic, which has a first electrically conductive conductive layer on at least one active surface, and the sensor is designed such that a collision-induced change in the electrical resistance of the first conductive layer can be detected , The inventive solution, a simple and reliable construction of the protective device can be achieved, since it can be dispensed with a complex design of the protective element and a to be arranged in the interior of the protective element and potentially failure-prone pump. Instead, the protective element is designed as a simple and inexpensive to produce plastic molding and has a feasible with simple means electrically conductive conductive layer. In the case of potential-compensating contacting of this conductive layer as a result of a collision with the obstacle, the electrical resistance of the conductive layer naturally changes. The sensor is according to the invention designed such that such a change in the electrical resistance of the first conductive layer can be detected. By way of example, the sensor system may have a measuring circuit electrically connected to the first conductive layer and known as such, which detects an electrical voltage applied to the first conductive layer and / or an electrical current flowing through the first conductive layer. Such a sensor is space-saving and inexpensive to implement and also fail-safe. The molded part can be produced in particular by means of prototyping a plastic granulate or by means of reshaping a plastic semifinished product. The active surface of the molded part on which the conductive layer is formed may be an outer or an inner surface of the molded part, which in a collision with the obstacle at least indirectly, that is, either directly by the obstacle or for example by an opposite wall portion of the molded part contacting. and / or deformable. The first conductive layer may in particular be formed in sections, preferably substantially completely, on the effective surface. Of course, a plurality of electrically conductive conductive layers, preferably on different active surfaces, may be provided on the mold element. In such an embodiment, the sensor system is advantageously designed such that a change in resistance of several, preferably all, of the conductive layers can be detected.

The solution according to the invention is particularly suitable for an industrial robot in the form of an articulated arm robot. However, the solution according to the invention can also be used for other stationary or autonomously moving handling devices, such as for example self-propelled industrial trucks, including manipulators, superstructures or the like connected to such a handling device.

In an embodiment of the invention, the first conductive layer is formed by means of a coating of the molded part with an electrically conductive material, in particular with graphite. At this Embodiment of the invention, the molded part can be made of a low cost, electrically non-conductive plastic. In particular metal, graphite or an electrically conductive plastic can be used as electrically conductive material. The coating of the molded part can be formed by a basically known method, for example by spraying or vapor deposition of the conductive material onto the molded part or by means of coextrusion.

In a further embodiment of the invention, the molding has a material composition which includes an electrically conductive filler, and the first conductive layer is thus formed by the material surface of the molding. Accordingly, in this embodiment of the invention can be dispensed with a separate manufacturing step for the formation of the conductive layer. In particular metal particles and / or shavings, preferably aluminum flakes, can be used as the filler. Alternatively or additionally, the material composition of the molded part may include soot particles.

In a further embodiment of the invention, the molding has a material composition comprising a thermoplastic elastomer, in particular PE-EPDM (polyethylene ethylene-propylene-diene rubber), preferably PP-EPDM (polypropylene ethylene-propylene-diene rubber), more preferably PE -LD (Polyethylene Low Density), includes. By using PE-EPDM or PP-EPDM, the molded part can be made soft-elastic and / or with a closed-cell structure.

In a further embodiment of the invention, the molding is designed at least two shells and has an upper and a lower shell. The lower shell is preferably provided for abutment with the outer wall portion. The upper and lower shell can each be manufactured separately and subsequently assembled components. Alternatively, the upper and the lower shell can be manufactured in a common manufacturing step and in this respect be integrally connected to each other. The upper and lower shell can be spaced apart in the thickness direction or arranged directly one above the other. Advantageously, the upper and lower shell are designed such that opposite wall portions of the upper and lower shell come into contact with each other in a collision of the molding with the obstacle or an existing contact between these two wall sections is reinforced. The first conductive layer may in particular be provided on an outer wall of the outer shell facing away from the outer wall section or on an inner wall of the outer shell facing the outer wall section. Alternatively, the first conductive layer may be provided on an upper side of the lower shell facing away from the outer wall section or on the underside of the lower shell. It is Of course, it is also possible that a plurality of conductive layers are provided and, for example, a conductive layer is formed on the underside of the upper shell and a further conductive layer on the upper side of the lower shell.

In a further embodiment of the invention, the upper shell and the lower shell are arranged in the thickness direction to form a cavity, wherein an elastically resilient in the thickness direction spring means is arranged in the cavity and designed such that a collision-induced deformation of the upper shell is cushioned by the spring means. Accordingly, the spring device is arranged such that in a collision of the molding with the obstacle initially the upper shell due to deformation cooperates with the spring means and is thereby sprung. In this case, the spring device in the thickness direction to form a gap from the upper shell spaced or be arranged without a gap to the upper shell in the cavity. Thus, a contact between the upper and the lower shell takes place only when the collision is sufficiently strong and the spring means in the thickness direction correspondingly strong spring. In this case, the first conductive layer is preferably provided on an inner wall of the outer shell facing the outer wall section of the industrial robot. Another conductive layer may be formed at the top of the lower shell. The spring device is electrically non-conductive. This embodiment of the invention avoids that even minor collision-induced deformations of the molded part lead to a contact between upper and lower shell and thus to a collision-induced change in the electrical resistance of the first conductive layer. This is counteracted by means of the spring device.

In a further embodiment of the invention, the lower shell is designed in the form of an electrically conductive foam core and the spring device has an arranged on an upper side of the foam core, electrically non-conductive and lattice-shaped foam structure. The foam core is formed from a plastic and has an electrically conductive material composition. For this purpose, the material composition may include an electrically conductive filler, for example metal particles, carbon black or the like. The latticed foam structure is preferably made of a plastic. The foam structure may be sprayed onto the top of the foam core or molded onto it. Alternatively, the foam structure may be welded or glued to the top of the foam core. If the molded part is a thermoforming component, in particular a twin-sheet component, the foam structure can be joined to the top side of the foam core before, after or during a corresponding shaping process. A lattice-shaped design of the foam structure has proven to be proved particularly advantageous. This is because a collision-induced triggering behavior of the sensor system can be influenced by simple means via a corresponding geometric design of the foam structure. For this purpose, for example, a thickness of the foam structure or a Shore hardness of the foam structure can be structurally dimensioned accordingly.

In a further embodiment of the invention, the molded part is designed with three shells, wherein an intermediate shell arranged in the thickness direction between the upper shell and the lower shell is provided which is conductive on both sides in relation to the thickness direction, and wherein the spring device is arranged on both sides of the intermediate shell. In this embodiment of the invention, the spring device preferably has two electrically non-conductive and latticed foam structures, wherein a first foam structure in the thickness direction between the upper shell and the intermediate shell and a second foam structure in the thickness direction between the intermediate shell and the lower shell is arranged. This embodiment of the invention allows a further improved reliability, since now a collision is also recognizable starting from a deformation of the lower shell. The intermediate shell is as it were enclosed between the upper shell and the lower shell. By means of the two foam structures of the spring device, on the one hand, the upper shell is cushioned relative to the intermediate shell and, on the other hand, the lower shell is cushioned relative to the intermediate shell in the thickness direction.

In a further embodiment of the invention, the upper and the lower shell differ from each other in material compositions. For example, the upper shell may be made of a comparatively more resilient material than the lower shell or vice versa. Preferably, the upper shell may be made of a plastic foam and the lower shell of a relatively dimensionally stable plastic sheet material or vice versa.

In a further embodiment of the invention, the upper and / or the lower shell is designed soft elastic. This soft elastic design can be material and / or structural. For example, the upper and / or the lower shell may be made of a flexible plastic material, preferably a plastic foam, and / or have an inherently flexible, for example, thin-walled, shape. By means of this embodiment of the invention, it is possible in particular to achieve a reduction in the forces acting between the molded part and the obstacle in the event of a collision. As a result, a risk of injury to the person working together with the industrial robot can be further reduced. In a further embodiment of the invention, a second electrically conductive conductive layer is provided, wherein the first conductive layer and the second conductive layer are arranged opposite each other between the lower and the upper shell such that the first and the second conductive layer in a collision of the molded part with the obstacle at least sections against each other are electrically contacted. The conductive layers may be spaced from each other in the thickness direction of the protective element or arranged directly one above the other. The conductive layers have mutually different electrical potentials. This refinement of the invention is particularly advantageous since, in the event of a collision, a change in resistance of the first conductive layer and / or the second conductive layer occurs even if the obstacle as such is insulated from the electrical potential of the first conductive layer and / or second conductive layer. In addition, the conductive layers are arranged in the interior of the molded part and thus protected from contamination and / or further undesirable environmental influences. With regard to the formation of the second conductive layer, that disclosed for the first conductive layer applies correspondingly, so that the second conductive layer can be formed either by means of a coating of the molded part with an electrically conductive material. Alternatively, the second conductive layer can be formed by a material surface of the molded part, provided that the molded part has an electrically conductive material composition.

In a further embodiment of the invention, the first conductive layer is formed on an inner wall of the upper shell and the second conductive layer is formed on one of the upper shell facing inner wall of the lower shell. The first conductive layer and / or the second conductive layer can in turn be formed by means of a coating or, if the material composition of the upper or lower shell should be electrically conductive, directly by a material surface, more precisely the corresponding inner wall, the lower or upper shell.

In a further embodiment of the invention, the first conductive layer in the form of a, in particular meandering, first conductor track is formed. Consequently, the active surface on which the first conductive layer is formed, not the entire surface but only on the first conductor electrically conductive. Preferably, the first conductor extends over the entire active surface. The conductor track can be formed, for example, in the form of conductor track sections which extend in parallel and are interconnected in an electrically conductive manner. Preferably, the first conductor track is designed as a meander conductor track. Alternatively, for example, a spiral-shaped configuration or an irregularly shaped, contiguous extension of the first interconnect is possible. If the first conductive layer is formed on the inner wall of the upper shell, it may damage the upper shell, for example in Form of a crack or a hole, come to an interruption of the first trace. As a result of such interruption, the electrical resistance of the first conductor increases. Such a change in resistance can be detected by means of the sensor system. This refinement of the invention achieves improved functional reliability, since damage to the molded part can be detected.

In a further embodiment of the invention, the first conductive layer in the form of a plurality at least partially formed in parallel extending, in particular strip-shaped, electrically separated from each other first conductor tracks. Consequently, the active surface on which the first conductive layer is formed, not the entire surface but only on the first conductor electrically conductive. Preferably, the first conductor tracks extend substantially over the entire width and / or length of the effective surface. The first interconnects may, for example, each have a width of 10 mm, preferably 3 mm. In this case, the first conductor tracks may be uniform or different from each other. The sensor can be designed in this embodiment of advantage such that a collision-induced change in the electrical resistance of each of the first interconnects can be detected. This embodiment of the invention makes it possible to narrow down a position of the contact of the obstacle on the molded part in the event of a collision. If the first conductor tracks extend in the width direction of the molded part, then a length position of the contact can be determined. If the first traces are instead extended in the length direction of the molding, a width position of the touch can be determined.

In a further embodiment of the invention, the second conductive layer in the form of a, in particular meandering, second conductor track is formed and extends transversely to the first conductor track or the first conductor tracks. Alternatively, for example, a spiral-shaped configuration or an irregularly shaped, contiguous extension of the second interconnect is possible. The second trace is transverse, i. rotated by about 90 °, arranged to the first trace or the first traces. If the second conductive layer is formed by means of a coating, in particular conductive material can be saved in this way.

In a further embodiment of the invention, the second conductive layer in the form of a plurality at least partially parallel extending, in particular strip-shaped, electrically separated from each other second conductor tracks, which are transverse to the first conductor or the first conductor tracks, formed. Preferably, in this case, the first conductive layer in the form of a plurality of parallel extending, in particular strip-shaped, electrically separated from each other first conductor tracks formed. Here are the second Conductor tracks are uniform or shaped differently. In this way, the first and the second tracks form a kind of grid. For example, the first interconnects are in the longitudinal direction and the second interconnects in the width direction of the molded part extends or vice versa. The sensor can be designed in this embodiment of advantage such that a collision-induced change in the electrical resistance of each of the first interconnects and each of the second interconnects can be detected. This embodiment of the invention makes it possible to determine a position of the contact of the obstacle on the molded part in the event of a collision. Depending on which of the first and on which of the second interconnects a collision-related resistance change is detected, a position in the grid formed by the interconnects can be determined. In addition, it can be advantageously determined whether there is a punctual or a flat collision, depending on whether only one or more adjacent interconnects experience a change in the electrical resistance.

In a further embodiment of the invention, the molded part is a thermoforming component, in particular a twin-sheet component. The thermoforming component can be produced by means of a basically known thermoforming process. As far as the molded part has a single-shell construction, it can be advantageously manufactured as a single-sheet component. Single-sheet forming is basically known in the field of plastics processing. As far as the molded part has a multi-shell structure and / or a cavity, it is particularly advantageous if it is used as a twin-sheet component, i. is produced by means of a basically known twin-sheet process. In the latter method, which is a special form of thermoforming, two plate-shaped semi-finished plastic products are heated in a single operation, vacuum deep drawn and welded together. Alternatively, in the case of a multi-shell construction, the molded part can be assembled from a plurality of single-sheet components produced separately by single-sheet molding. The single-sheet components can be glued, welded or sewn together, for example, to produce the multi-shell molded part. This embodiment of the invention, a particularly cost-effective and material-saving manufacturable molded part can be achieved.

In a further embodiment of the invention, the molded part has a hermetically sealed cavity and the sensor is designed such that a collision-induced change in the air pressure in the cavity can be detected. To detect the collision-induced change in air pressure, the sensor system can have a pressure sensor, which can be arranged in the interior of the molded part. By means of this embodiment of the invention, a redundant collision detection can be achieved, namely on the one hand based on detection of the collision-related change in the electrical resistance of the conductive layer and on the other hand based on a collision-induced change in the air pressure in the cavity, and thus a particularly high reliability of the protective device can be achieved.

In a further embodiment of the invention, the cavity between the lower and the upper shell is formed, wherein these are connected to each other airtight.

The object underlying the invention is achieved for a protective element of the type mentioned above in that it is designed in the form of a molded part made of a plastic according to one of the preceding claims.

Further advantages and features of the invention will become apparent from the claims and from the following description of preferred embodiments of the invention, which are illustrated by the drawings.

Fig. 1 shows a schematic perspective view of an industrial robot with a

Embodiment of a protective device according to the invention, comprising two protective elements according to the invention of a first embodiment and a sensor associated with the sensors,

Fig. 2, the two protective elements according to Fig. 1 in a schematic

Perspective view

Fig. 3a, 3b of the protective elements according to FIGS. 1 and 2 in a schematic

Bottom view (Figure 3a) and a schematic side view (Figure 3b),

Fig. 4a, 4b, the protective element according to FIGS. 3a, 3b in schematic

FIG. 4 a) and a schematic cross-sectional view along a section line B-B according to FIG. 3 b (FIG. 4 b), FIG.

Fig. 4c, 4d in an enlarged view of a region I of Fig. 4b for a first

4c) and a second embodiment variant (FIG. 4d) of the protective element according to FIGS. 3a to 4b, FIG.

5a, 5b, a second embodiment of a protective element according to the invention in one

Longitudinal and a cross-sectional view corresponding to FIGS. 4a and 4b, in an enlarged view, a portion II of Fig. 5b for a first embodiment (Fig. 5c) and a second embodiment (Fig. 5d) of the protective element according to Figs. 5a and 5b, a third embodiment of a protective element according to the invention in a longitudinal and a cross-sectional view corresponding to the Fig. 4a and 4b, in an enlarged view, a region III of Fig. 6b for a first embodiment according to the invention (Fig. 6c) and a second embodiment according to the invention (Fig. 6d) of the protective element according to Fig. 6a, 6b, a schematic perspective view of another embodiment of a protective element according to the invention, in a schematic perspective view of another embodiment of a protective element according to the invention, in a schematic perspective view of an upper shell of another embodiment of a protective element according to the invention with a in the form of a first conductor a 7 is a schematic, simplified schematic representation of the first conductive layer according to FIGS. 7 and 8 together with a full-surface-area second conductive layer, FIG.

10a, 10b respectively show a schematic, simplified schematic diagram of a second (FIG. 10a) and a third embodiment according to the invention (FIG. 10b) of a first conductive layer and a second conductive layer, FIG.

Fig. 1 1, in a schematic, simplified schematic diagram of a fourth invention

Embodiment of a first and a second conductive layer and

12a, 12b respectively show a schematic, simplified schematic representation of a fifth (FIG. 12a) and a sixth embodiment according to the invention (FIG. 12b) of a first conductive layer and a second conductive layer. According to FIG. 1, an industrial robot R in the form of an articulated arm robot is provided with a protective device 1. The articulated arm robot R has a first articulated arm 2, which is articulated pivotably about a substantially horizontally oriented axis of rotation on a base portion 3. The base portion 3 is rotatably mounted about a substantially vertically oriented axis of rotation on a foot section 4, which is screwed to a foundation F ground-tight. Furthermore, the articulated arm robot R has a second articulated arm 5, which at one end has an unspecified tool holder 6 and at the other end is pivotably connected to the first articulated arm 2 about a substantially horizontally oriented axis of rotation. The tool holder 6 can pivot about a substantially horizontally oriented axis of rotation relative to the second articulated arm 5 and also be rotatable about the longitudinal axis of the second articulated arm 5 with respect to this. The articulated arms 2, 5 and the base portion 3 and the tool holder 6 are in a generally known manner by means of drive motors not shown closer to the respective axes of rotation displaced, so that the articulated robot R can perform work within a work area A. In the present case, an obstacle H is arranged within the working area A of the articulated arm robot R, which may be stationary or movable. The obstacle H is shown in FIG. 1 only schematically and greatly simplified-in the sense of a generic placeholder-and, in particular, can be a person working in the working area A. Alternatively, it is also possible that the obstacle H by a portion, for example, the base portion 3 or the foot portion 4, the Gelenkarmroboters R is formed. The protective device 1 is used to ensure adequate safety and is designed in a manner to be explained in more detail such that a collision between the industrial robot R and the obstacle H can be detected in order to enable an emergency shutdown of the industrial robot R in the event of a collision.

For this purpose, the protective device 1 protective elements 7a, which are provided as a shell for an outer wall portion 8 of the industrial robot R. In the exemplary embodiment according to FIG. 1, two protective elements 7a are provided, which encase the second articulated arm 5 substantially completely. Of course, it is also possible that fewer or more than two protective elements 7a are provided and that these are alternatively or additionally provided, for example, on the first articulated arm 2 and / or the base section 3. Furthermore, the protective device 1 has a protective element 7a, 7a associated with the sensor 9, which is designed such that a collision between the obstacle H and at least one of the protective elements 7a can be detected. The sensor system 9 is merely simplified and shown schematically with reference to FIG. 1 and may, for example, comprise electrical and / or electronic components which may be arranged inside and / or outside the respective protective element 7a, 7a. The sensor system 9 is designed such that at least one physical quantity, which is not described in further detail, can be detected on the respective protective element 7a, which is to be clarified with reference to FIG. 1 by means of the connections between the sensor system 9 and the respective protective element 7a shown by dashed lines. Furthermore, the sensor system 9 can be prepared to transmit an output signal M to a control unit of the articulated-arm robot R that is not shown in greater detail as a function of the physical quantities detected on the protective elements 7a, 7a. By means of the signal M, an emergency shutdown of the industrial robot R can be effected in the event of a collision.

As can be seen in particular with reference to FIGS. 2 and 3a and 3b, the protective elements 7a, 7a are each in the form of a molded part. The molded parts 7a, 7a are each made of plastic and have a substantially identical structure, so that below to avoid repetition only one of the two mold parts 7a, 7a is discussed in more detail.

The molded part 7a has a half-shell-like shape whose inner contour 10a can be substantially modeled on a contour of the outer wall section 8 of the industrial robot R. Further, the molded part 7a has a recess 1 1 a, which releases the tool holder 6 of the industrial robot R ready assembled state. Furthermore, the molded part 7a has a first electrically conductive conductive layer 13a on an active surface facing away from the outer wall section 8 in the ready-to-use state. The first electrically conductive conductive layer 13a is formed substantially over the entire surface of the active surface. Of course, it is also possible for the first conductive layer 13a to be formed only in sections, for example in strips, lattices or meanders. In a first embodiment according to FIG. 4 c, the conductive layer 13 a is formed by means of a coating of the molded part 7 a with an electrically conductive material 14. In the present case, graphite is provided as the conductive material 14a. As an alternative to the variant according to FIG. 4c, according to FIG. 4d, the conductive layer 13a may be formed by a material surface surface of the molded part 7a. For this purpose, the molding 7a has a material composition W including an electrically conductive filler 15a. As filler 15a aluminum particles are provided. Furthermore, the material composition W has a thermoplastic elastomer. As the thermoplastic elastomer PP-EPDM (polypropylene ethylene-propylene-diene rubber) is selected in the embodiment according to FIGS. 4a to 4d.

The sensor 9 is designed such that a collision-induced change in the electrical resistance R1 of the conductive layer 13a can be detected. With reference to FIG. 1, this is schematically with the indicated there dashed line connection between the sensor 9 and the mold element 7a. The electrical resistance R1 changes due to an equipotential bonding between the obstacle H and the conductive layer 13a. This presupposes that the obstacle H is not electrically insulated from the electrical potential of the conductive layer 13a.

The embodiments of protective elements 7b, 7c and 7i and 7j according to FIGS. 5a to 6f according to the invention have, in terms of their structural and functional design, similarities with the embodiment previously described with reference to FIGS. 1 to 4c. To avoid repetition, reference is therefore made to the disclosure of the embodiment according to FIGS. 1 to 4c. In the following, only the essential differences of the embodiments according to FIGS. 5a to 6f will be discussed. Functional and / or identical sections and parts of these embodiments are provided with the same reference numerals with the addition of changed lowercase letters.

The embodiment according to FIGS. 5a to 5d provides a clamshell shaped part 7b. The molded part 7b has in this respect an upper shell 16b and a lower shell 17b. The lower shell 17b is presently provided for abutment against the outer wall portion 8 of the industrial robot R. Alternatively, the lower shell 17b may be spaced apart from the outer wall section 8 in the assembled state. As a result, an additional buffer path can be achieved in the event of a collision. In addition, it is possible for this purpose, to arrange a soft elastic material between the lower shell 17 b and the outer wall portion 8. As can be seen from the enlarged illustrations of FIGS. 5c and 5d, the molded part 7b has a first electrically conductive conductive layer 13b and a second electrical conductive layer 18b. The conductive layers 13b, 18b are disposed opposite to each other between the upper shell 16b and the lower shell 17b. In this case, the conductive layers 13b, 18b contact already directly in a collision-uninfluenced state of the molded part 7b. In the variant according to FIG. 5c, the conductive layers 13b and 18b are each formed by means of a coating of the upper shell 16b or of the lower shell 17b with an electrically conductive material 14b, namely graphite. In the variant according to FIG. 5d, the conductive layers 13b, 18b are each formed by the respective material surface of the upper shell 16b or the lower shell 17b. For this purpose, the lower shell has the material composition Wb with an electrically conductive filler 15b. In contrast, the upper shell 16a has a deviating material composition Vb, which contains an electrically conductive filler 15b, namely graphite. The upper shell 16b is made soft elastic. Alternatively or additionally, the lower shell 17b may be made soft elastic. In the event of a collision with the obstacle H, a local deformation of the upper and lower shells 16b, 17b occurs in any case, with the electrically conductive conductive layers 13b, 18b being pressed against one another more intensively. As a result of this increased pressure, a change in the electrical resistance of the first conductive layer 13b and / or the second conductive layer 18b can be detected by means of the sensor system 9.

In accordance with the embodiment according to FIGS. 5a to 5d, the embodiment according to FIGS. 6a to 6d provides a two-shell embodiment of the molding 7c there. Like the molded part 7b, the molded part 7c has an upper shell 16c and a lower shell 17c, wherein the lower shell 17c is in turn provided for bearing against the outer wall section 8. In contrast to the molded part 7b, the molded part 7c provides a cavity 19, which is arranged in the thickness direction of the molded part 7c between the lower shell 17c and the upper shell 16c. The cavity 19 is sealed airtight to the outside. The molded part 7c in turn has a first and a second electrically conductive conductive layer 13c and 18c, respectively. The first conductive layer 13c is formed on an inner surface of the upper shell 16c. The second conductive layer 18c is formed on an inner surface of the lower shell 17c. In that regard, the conductive layers 13c and 18c are arranged opposite to each other in accordance with the embodiment of FIGS. 5a to 5d between the lower shell 17c and the upper shell 16c. In contrast to this, however, the conductive layers 13c, 18c are spaced apart in the thickness direction by the cavity 19 formed between the upper and lower shell 16c, 17c. In the present case, the distance is about 5 mm, but this does not necessarily have to be the case. Depending on the application and in particular dimension of the articulated arm robot R, the distance may be greater or less than 5 mm.

In the embodiment according to FIG. 6c, the conductive layers 13c, 18c are each formed by means of a coating of the upper shell 16c or the lower shell 17c with an electrically conductive material 14c. The variant according to FIG. 7d provides a configuration of the upper shell 16c and the conductive layer 13c formed thereon. In contrast, the conductive layer 18c is formed by the inner material surface of the lower shell 17c, which for this purpose has an electrically conductive material composition Wc with an electrically conductive filler 15c.

The upper shell 16c approaches in a collision of the molding 7c with the obstacle H due to a soft elastic design of the molding 7c of the lower shell 17c. For this purpose, for example, the upper shell 16c made of a plastic foam and / or be thin-walled and thus compliant. This results in an electrical contact between the first conductive layer 13c and the second conductive layer 18c. This causes a change in the electrical resistance of the first conductive layer 13c and / or the second conductive layer 18c, which can be detected by means of the sensor system 9. In addition, due to the airtight completion of the cavity 19, there is a collision-related change in a pressure P in the cavity 19. The sensor system 9 is designed such that such a collision-induced change in the pressure P in the cavity 19 can be detected. For this purpose, the sensor 9 may have a pressure sensor which may be arranged in the cavity 19.

With reference to FIG. 6e, a molded part 7i can be seen, which is essentially identical in terms of its structural and functional design to the molded part according to FIGS. 6a to 6d. To avoid repetition, reference is made in this respect to the disclosure in connection with the molded part 7c, which applies analogously to the molded part 7i. In contrast to the molded part 7c, the molded part 7i provides a spring device FE. The spring device FE is arranged in the thickness direction between the upper shell 16i and the lower shell 17i. The spring device FE is arranged in a cavity 19i formed in the thickness direction between the upper shell 16i and the lower shell 17i and designed such that a collision-induced deformation of the upper shell 16i is cushioned by means of the spring device FE. This configuration avoids that even comparatively slight collision-induced deformations of the molded part 7i lead to a contacting of the upper shell 16i to the lower shell 17i and thus to a collision-induced change in resistance of the first conductive layer 16 - which is provided on one of the lower shell 17i facing inner side of the upper shell 16i. to lead. In that regard, the spring device FE acts as a kind of flexible spacer. Here, the lower shell is presently designed in the form of a foam core 17i. The foam core 17i is made of plastic, wherein the plastic has an electrically conductive material composition. For this purpose, the plastic material may be provided with a suitable filling material, for example metal particles, carbon black or the like. The material surface of the foam core 17i thus forms a second electrical conductive layer. In one embodiment, not shown, the foam core may have a plurality of layers, wherein at least one upper - provided for contacting with the upper shell - layer is conductive. The spring device FE is arranged on an upper side O of the foam core 17i. The upper side O of the foam core 17i faces the unspecified inner side of the upper shell 16i. In this case, the spring device on an electrically non-conductive and lattice-shaped foam structure SR. The foam structure SR is made of plastic. The foam structure SR may be loosely inserted into the cavity 19i between the upper shell 16i and the foam core 17i. Alternatively, the foam structure SR may be firmly connected to the top O. For example, the foam structure SR on the top O or sprayed onto this, glued or welded.

With reference to FIG. 6f, a molded part 7j can be seen which, in terms of its structural and functional design, has correspondences with the molded part 7i according to FIG. 6e. To avoid repetition, reference is made in this respect to the disclosure in connection with the molded part 7i, which applies analogously to the molded part 7j. In contrast to the molded part 7i, the molded part 7j is designed with three shells. In this case, an intermediate shell ZS is provided in the thickness direction between the upper shell 16j and the lower shell 17j. In the present case, the lower shell is again designed in the form of an electrically conductive foam core 17j. The intermediate shell ZS is elastic and has on both sides - i. both on its upper side facing the upper shell 16j, and on its lower side facing the lower shell 17j - in each case an electrically conductive conductive layer. In the present case, the spring device FE is arranged on both sides of the intermediate shell ZS and has a first foam structure SR, which is arranged in the thickness direction between the lower shell 17j and the intermediate shells ZS, and a second foam structure SR ', which in the thickness direction between the intermediate shell ZS and the upper shell 16j is arranged. The two foam structures SR, SR 'are in turn electrically non-conductive. The molded part 7j thus permits collision detection based on a deformation of the upper shell 16j on the one hand and on the other on the basis of a deformation of the lower shell 17j. The molded parts 7a, 7b and 7c and 7i and 7j have in common that they are each manufactured as a thermoforming component , That is, the mold parts 7a to 7c and 7i and 7j are each manufactured by means of a thermoforming process basically known in the field of plastics technology. This thermoforming method provides for heating a thermoplastic semifinished product, for example a plastic plate goods or a plate-shaped plastic foam before. The heated plastic semi-finished product is vacuum-drawn in a thermoforming mold, cooled and demoulded.

Here, the mold parts 7b and 7c are made in particular as twin-sheet components. That is, for their preparation, a known as such twin-sheet thermoforming method is provided. In this special known in the field of plastics technology special form of thermoforming two plate-shaped plastic semi-finished, placed between each other opposing thermoforming molds and deep-drawn vacuum-deepened in the thermoforming dies, the thermoforming molds brought against each other for conditioning and the thermoformed plastic sheets are welded together. The conductive layers 13a-c and 18b and 18c may each be configured differently, for example over the entire surface, meander-shaped, strip-shaped or the like. Particularly in the case of an at least bivalve embodiment of the molded part according to the embodiment according to FIGS. 6a to 6d and according to the embodiments according to FIGS. 6e and 6f, different advantages and functionalities can be achieved by means of differently configured conductive layers. Hereinafter, specific embodiments of the first conductive layer and the second conductive layer will be described in greater detail with reference to FIGS. 7 to 12b.

According to FIG. 7, a first conductive layer in the form of a meander-shaped first printed conductor 13d is formed on an inner wall 20d of an upper shell 16d of a molded part, wherein the upper shell 16d is rotated approximately 180 ° along its longitudinal axis for better recognition of the inner conductive line 13d. The first conductor track 13d extends substantially over the entire inner wall 20d. A connection section 21 d, which is provided for electrically conductive connection to the sensor system 9, is arranged in the width direction of the upper shell 16d approximately in the middle of the end face. Starting from the connection section 21 d, the first conductor track 13d extends meander-shaped. Here, adjacent conductor portions 22d extending parallel to each other and extending in the width direction of the upper shell 16d are electrically conductively connected to each other by means of a bent connection portion 23d, respectively. The inner wall 20d is only electrically conductive on the first conductor track 13d. By contrast, no electrical conductivity is present in the regions of the inner wall 20d arranged between the conductor track sections 22d. The first interconnect 13d is provided to be contacted with a second conductive layer in the event of a collision of the molded part with the obstacle H. This second conductive layer is advantageously formed on a lower shell of the molded part assigned to the upper shell 16d. Preferably, the second conductive layer is formed on an inner wall of the lower shell, which faces the inner wall 20d of the upper shell 16d. The second conductive layer can in turn be configured differently.

According to FIG. 9, as is to be clarified on the basis of the greatly simplified schematic diagram, a second conductive layer 18d is provided, which in the present case has the entire surface. The second conductive layer 18d thus forms a continuous contact surface on which the meander-shaped printed conductor track 13d can be contacted with the obstacle H in the event of a collision of the molded part. The second conductive layer 18d has a terminal portion 24d. The connection section 24d is provided for an electrically conductive connection of the second conductive layer 18d to the sensor system 9. In addition to the connection section 21 d, the first conductor track 13d may be provided with a second connection section (not shown here). The second connection section is advantageously arranged on an end of the conductor track 13d facing away from the first connection section 21d. As a result, it is advantageously possible to detect a defect-related change in the resistance of the printed conductor 13d independently of a contact with the second conductive layer 18d, for example by means of the sensor system 9, which has been suitably set up for this purpose.

In the embodiment according to FIG. 10a, instead of the meandering first conductor track 13d, a first conductive layer is provided, which is formed in the form of a plurality of parallel, strip-shaped, electrically separated first conductor tracks 13e. The first conductor tracks 13e extend parallel to one another and each have a connection section 21e which is provided with the sensor system 9 for connecting the respective first conductor track 13e. In this embodiment, the sensor 9 is advantageously designed such that a collision-induced change in the electrical resistance of each of the first interconnects 13e can be detected separately. Depending on the orientation, the first conductor tracks 13e may extend essentially over the entire width or the entire length of the inner wall of the upper shell. The first traces have a width of about 10mm with respect to the plane of the drawing of FIG. 10a. This embodiment makes it possible to narrow down a position of the contact of the obstacle H in the event of a collision, if only some of the first interconnects 13e are electrically contacted to the second conductive layer 18d. If the first conductor tracks 13e extend, for example, in the width direction of the upper shell 16d, a length position of the contact of the obstacle on the upper shell 16d can be determined. If the first conductor tracks 13e instead extend in the length direction of the upper shell 16d, a width position can be determined.

The embodiment according to FIG. 10b differs from the embodiment according to FIG. 10a only in that first printed conductors 13f are provided which have a smaller width of approximately 3 mm than the first printed conductors 13e. In this way, in particular a higher resolution of the above-described position determination can be achieved.

The embodiment according to FIG. 11 provides a second conductive layer, which is designed in the form of a meander-shaped second conductor track 18e and extends transversely to the first conductor track 13d. Instead of Fig. 1 1 apparent rotated by 90 ° from each other Arrangement of the meandering conductor tracks 13d and 18e, for example, a 45 or 135 ° twisted arrangement is conceivable.

The embodiment according to FIG. 12a differs from the embodiment according to FIG. 10a in that, instead of the completely formed second conductive layer 18d, a second conductive layer is provided in the form of a plurality of parallel, strip-shaped, electrically separated conductive tracks 18f. The second interconnects 18f are arranged transversely to the first interconnects 13e. Each of the second conductive lines 18f is provided with a terminal portion 24f. The connection sections 24f are provided for the electrical connection of the respective second conductor track 18f to the sensor system 9. In this embodiment, the sensor 9 is advantageously designed such that a collision-induced change in the electrical resistance of each of the first interconnects 13e and each of the second interconnects 18f is separately detectable. The first conductor tracks 13e and the second conductor tracks 18f form a kind of contact grid by the arrangement rotated by 90 ° relative to one another. In the event of a collision, therefore, a point of contact of the obstacle H on the upper shell 16d can be localized, depending on which of the first interconnects 13e and second interconnects 18f a change in the respective electrical resistance is detected.

The embodiment according to FIG. 12b differs from the embodiment according to FIG. 12a only in that first conductor tracks 13f and second conductor tracks 18g are provided which have a reduced strip width with respect to the first conductor tracks 13e and the second conductor tracks 18f. In this way, an improved position resolution can be achieved in the determination of a contact point of the obstacle H on the upper shell 16d. In addition, as complete a collision detection as possible can be achieved.

In the same way as the conductor track 13d according to FIG. 9, the conductor tracks according to FIGS. 10a to 12b may each be provided with an additional connection section for the purpose of detecting a defect-related resistance change.

Claims

claims

1 . Protective device (1) for an industrial robot (R) with at least one protective element, which is provided as a shell for an outer wall section (8) of the industrial robot (R), and a sensor (9) associated with the protective element, which is designed such that a collision between the protective element and an obstacle (H) is detectable, characterized in that the protective element is a molded part made of plastic (7a-c, 7i, 7j), the at least one active surface having a first electrically conductive conductive layer (13a-f) , and the sensor (9) is designed such that a collision-induced change in the electrical resistance (R1) of the first conductive layer (13a-f) can be detected.

2. Protection device (1) according to claim 1, characterized in that the first conductive layer (13a-f) by means of a coating of the molded part (7a-c, 7i, 7j) with an electrically conductive material (14a-c), in particular with graphite , is formed.

3. protection device (1) according to claim 1, characterized in that the molded part (7a-c) has a material composition (Wa, Wb, Wc, Vb), which includes an electrically conductive filler (15a-c, 1 15b), and the first conductive layer (13a-f) is thus formed by a material surface of the molded part (7a-c, 7i, 7j).

4. Protection device (1) according to one of the preceding claims, characterized in that the molded part (7a-c, 7i, 7j) has a material composition (Wa, Wb, Wc, Vb) which comprises a thermoplastic elastomer, in particular PE-EPDM, preferably PP-EPDM, more preferably PE-LD.

5. Protection device (1) according to one of the preceding claims, characterized in that the molded part (7b, 7c, 7i, 7j) is designed at least two shells and an upper shell (16b, 16c, 16d, 16i, 16j) and a lower shell (17b , 17c, 17i, 17j).

6. Protection device (1) according to claim 5, characterized in that the upper shell (16i, 16j) and the lower shell (17i, 17j) in the thickness direction to form a cavity (19i) are arranged, wherein an elastically yielding in the thickness direction spring means (FE ) is arranged in the cavity (19i) and designed such that a collision-induced deformation of the upper shell (16i, 16j) is cushioned by means of the spring device (FE).

7. Protection device (1) according to claim 6, characterized in that the lower shell in the form of an electrically conductive foam core (17i, 17j) is formed, and that the spring means at least one on an upper side (0) of the foam core (17i, 17j) arranged , electrically non-conductive and latticed foam structure (SR).

8. Protection device (1) according to claim 6 or 7, characterized in that the molded part (7j) is designed dreischalig, wherein in the thickness direction between the upper shell (16j) and the lower shell (17j) arranged intermediate shell (ZS) is provided, which - Is formed on both sides conductive in relation to the thickness direction, and wherein the spring means (FE) on both sides of the intermediate shell (ZS) is arranged.

9. Protection device (1) according to one of claims 5 to 8, characterized in that the upper shell (16b, 16c, 16d, 16i, 16j) and the lower shell (17b, 17c, 17i, 17j) deviating material compositions (Wb, Vb , Wc).

10. Protection device (1) according to one of claims 5 to 9, characterized in that the upper shell (16b, 16c, 16d, 16i, 16j) and / or the lower shell (17b, 17c, 17i, 17j) is configured soft elastic.

1 1. Protection device (1) according to one of claims 5 to 10, characterized in that a second electrically conductive conductive layer (18b-g) is provided, wherein the first conductive layer (13b-f) and the second conductive layer (18b-g) such between the Lower shell (17b, 17c, 17i, 17j) and the upper shell (16b, 16c, 16d, 16i, 16j) are arranged opposite to each other that the first and the second conductive layer in a collision of the molding (7b, 7c, 7i, 7j) at least partially against each other are electrically contacted.

12. Protection device (1) according to claim 1 1, characterized in that the first conductive layer (13b-f) on an inner wall of the upper shell (16b-d, 16i) is formed and the second conductive layer (18b-g) on one of the upper shell (16b-d) facing the inner wall of the lower shell (17b, 17c, 17i) is formed.

13. Protection device (1) according to claim 1 1 or 12, characterized in that the first conductive layer in the form of a, in particular meandering, first conductor track (13d) is formed.

14, protection device (1) according to claim 1 1 or 12, characterized in that the first conductive layer in the form of a plurality at least partially parallel extending, in particular strip-shaped, electrically separate from each other first conductor tracks (13e, 13f) is formed.

15. Protection device (1) according to claim 13 or 14, characterized in that the second conductive layer in the form of a, in particular meandering, second conductor track (18e) and formed transversely to the first conductor track (13d, 13e) or the first conductor tracks (13f) extends.

16. Protection device (1) according to claim 13 or 14, characterized in that the second conductive layer in the form of a plurality at least partially parallel extending, in particular strip-shaped, electrically separated from each other second conductor tracks (18f, 18g) transverse to the first conductor track (13d , 13e) or the first conductor tracks (13f) are formed.

17. Protection device (1) according to the preamble of claim 1 or any one of the preceding claims, characterized in that the molded part is a thermoforming component (7a-c, 7i, 7j), in particular a twin-sheet component (7b, 7c , 7i, 7j), is.

18. Protection device (1) according to one of the preceding claims, characterized in that the molded part (7c) has a hermetically sealed cavity (19) and the sensor (9) is designed such that a collision-induced change in the air pressure (P) in the Cavity (19) can be detected.

19. Protection device (1) according to claim 18, characterized in that the cavity (19) between the lower shell (17c) and the upper shell (16c) is formed, wherein these are connected to each other airtight.

20. Protection element for a protective device (1) according to one of the preceding claims, characterized in that the protective element in the form of a molded plastic part (7a-c, 7i, 7j) is formed according to one of the preceding claims.