Patent Application
20240342926
The invention relates to tool coupling devices for coupling tools to the robot arm of a robot, and to tool coupling device sets comprising such tool coupling devices. Furthermore, the invention also relates to a robot having such a tool coupling device and to a manufacturing or handling system having a plurality of robots with tool coupling devices.
Known tool coupling devices are used in order to be able to change tools quickly and with little effort, i.e. to be able to separate them from a robot arm of an industrial robot in order to be able to subsequently couple and lock another tool to the robot arm or to attach the separated tool to a robot arm of another robot.
Both pneumatic and manually operated tool coupling devices are known from the prior art. However, fundamentally different tool coupling devices are usually used for this purpose. Changing a tool intended for a pneumatically controlled tool coupling device to a robot intended for manual tool changing therefore usually causes great effort.
A tool coupling device is provided which can be operated more economically than known systems, in particular by increasing the flexibility of use and thus reducing the number of tools to be kept in stock.
A tool coupling device with two coupling subdevices is proposed. One of the coupling subdevices is intended to be located at the distal end of a robot arm of a robot, i.e. fastened there, in particular by means of a screw connection. The other coupling subdevice is intended to be provided on a tool that can be coupled to the robot arm. This can be a gripper, a cutting tool or a discharge head for liquids, for example. Here, too, the coupling part device is usually attached to the mold by means of a screw connection.
Generally, it is not important which of the coupling subdevices is provided on the tool side and which on the robot arm side. Insofar as specifications are made in this respect in the following, these are to be understood as exemplary.
The two coupling subdevices of a tool coupling device can be decoupled from each other and coupled to each other for the purpose of tool changing. Changing a tool is required when the robot is to be equipped with another tool or when the tool shall be used on another robot. Maintenance or cleaning of the tool can also be a reason for an intermediate decoupling.
For the purpose of easy coupling and decoupling, the coupling subdevices have cooperating coupling means. A first of the coupling subdevices, which may be the robot-side coupling subdevice or the tool-side subdevice, has a coupling socket extending in a coupling direction for the purpose of insertion into a corresponding coupling recess of the other and second coupling subdevice.
In order to lock the two coupling subdevices together and then to be able to guide the tool by means of the robot arm, the first coupling subdevice has a plurality of ball channels on the coupling socket, in each of which a ball body being arranged as a locking body.
Preferably, at least four ball channels are provided, each of which is provided with a ball body. Preferably, the ball channels are designed with different orientations. In particular preferably, the ball channels are distributed over the rotationally symmetrical coupling socket and extend radially outwardly, the ball channels in particular preferably being distributed uniformly over the circumference.
The ball bodies are displaceable in the ball channels between an extended coupling position and a retracted release position. For displacement of the ball bodies, the first coupling subdevice has an internal actuating body. This actuating body is movable relative to the coupling socket and the ball channels and acts directly or indirectly on the ball bodies. When the actuating body is displaced into a coupling end position, it presses and holds the ball bodies outwardly into their extended coupling position in each case and prevents the ball bodies from retracting. This creates a locked state.
The actuating body preferably has a widening shape and, in particular, is rotationally symmetrical on its outer side. In particular, the actuating body can have the shape of at least one cone section in the region of an actuating surface that acts on the ball bodies.
For interaction with the ball bodies, the second coupling subdevice has at least one retaining edge on the inner side of the coupling recess. When the coupling subdevice is inserted into the coupling recess and if the ball bodies are radially extended and are secured by the actuating body, the radially extended ball bodies together with the retaining edge secure the coupled state of the coupling subdevices and prevent separation of the coupling subdevices.
To separate the coupling subdevices from each other again, the actuating body is moved out of the coupling end position so that the ball bodies can move inwards in the ball channels again thus terminating the locked state. The coupling subdevices can now be separated from each other again.
According to a first aspect, the displacement of the actuating body is performed by an electric motor. This electric motor is part of the first coupling subdevice and is mechanically connected to the actuating body in order to be able to move the actuating body into the lo coupling end position and out of this coupling end position.
The electric motor can be designed as a linear actuator. However, an electric motor with a rotatable output shaft coupled to the actuating body via a gear unit is preferred. Preferably, this gear unit can be designed to convert the rotational movement of the output shaft into a translational movement in order to directly displace the actuating body or to move a translationally displaceable control element, the movement of which is directly or indirectly converted into the movement of the actuating body.
Preferably, the gear unit represents a self-locking safety device with respect to an effect direction from the actuating body to the electric motor. This means that the gear unit is designed in such a way that a force acting on the actuating body results in self-locking in the gear unit and the force is thus not passed on to the electric motor. If the electric motor fails, this does not result in the secured state of the coupling subdevices being lost.
It is particularly advantageous if the gear unit comprises a worm gear. This can be in direct engagement with an internal thread on the actuating body or with the said linearly movable intermediate element. The gear worm is an advantageous way of providing the above-mentioned self-locking effect in the direction of action from the actuating body to the electric motor.
In a preferred variant, a spring device is provided on the first coupling subdevice, by means of which the actuating body is permanently pressed in the direction of its coupling end position. Since the electric motor preferably acts centrally on the actuating body on a side of the actuating body opposite the actuating surface, the spring device preferably comprises a plurality of spring elements acting on the actuating body said plurality of spring elements being distributed over the circumference thereof.
The spring device can serve in particular the purpose of maintaining the locked state in the event of a failure of the electric motor. In this way, safety is ensured even in case of the gear unit and/or the electric motor not providing a self-locking effect.
According to a second aspect, the tool coupling device is not or not exclusively operable by means of said electric motor, but comprises an external manual control lever for manual operation.
Thus, it is provided here that the establishment of the secured state and the released state is performed by a manual actuation of said manual control lever directly at the tool coupling device. This represents a simple and cost-effective way of implementing a tool coupling device.
The manual control lever is preferably designed as a pivotable manual control lever. The manual control lever is preferably pivotably mounted on the first coupling subdevice, preferably in the region of an outer contour. In particular preferably, a pivot axis about which the manual control lever is pivotable extends parallel to the coupling direction. Preferably, the manual control lever has a curved or angled shape so that it fits against the outside of a housing of the first coupling subdevice in a space-saving manner when the actuating body is in its coupling end position. By swinging the manual control lever outwardly from this position, the actuating body can be moved out of the coupling end position.
In this variant with a manual control lever, a preferred design can also provide that a spring device is provided on the first coupling subdevice, by means of which the actuating body is permanently force-loaded in the direction of its coupling end position. Such a spring device reduces the risk of dangerous incorrect operation. Even if, during a tool change, the manual control lever is not pressed into its position assigned to the coupling end position of the actuating body, the spring acts in this direction and ensures a safe coupling between the coupling subdevices. If decoupling of the coupling subdevices is intended, the manual control lever is displaced out of its end position against the force of the spring device. The force required to release the coupling is therefore greater than the force required to couple the coupling component devices.
A holding device can be provided to ensure that the manual control lever remains in the position it has reached after it has been pivoted, despite the spring force.
For both the design of the first coupling subdevice with electric motor and for the design with manual control lever it is preferred, that the electric motor or the manual control lever act first on a linearly movable control element and that the movement of this control element acts indirectly via a direction changing gear unit on the actuating body, preferably on a region of the actuating body opposite the actuating surface of the actuating body. The linearly movable control element is preferably movable in a guided manner, its direction of movement relative to the direction of movement of the actuating body preferably enclosing an angle greater than 0°, in particular greater than 10°, and preferably an angle of 90°.
In particular, two designs for such a direction changing gear unit are preferred, with both designs being usable for a design with a manual control lever as well as for a design with an electric motor: In a first design, the direction changing gear unit is designed as a link gear unit. In this case, a rigid link is provided as an intermediate element, which is pivotably attached to both the control element and pivotably attached to the actuating body. The displacement of the control element thus leads to a displacement of the swivel axis and thus to a tilting of the link, which thereby displaces the actuating body and finally secures the ball bodies.
When the actuating body reaches its coupling end position, the link is preferably in a position that is not angled or only slightly angled relative to the direction of movement of the actuating body. This means that an imaginary connecting line between the two pivot axes of the link with the said direction of movement encloses an angle of less than 30°, preferably less than 10°. This is very suitable for achieving the self-locking effect described above.
In a second design using a direction changing gear unit, it is provided that the direction changing gear unit has a guide surface on the actuating body which is inclined with respect to the direction of movement of the control element, in particular enclosing an angle of between 5° and 40° with the direction of movement of the control element, in particular preferably between 5° and 30°. Alternatively or additionally, a guide surface can also be provided on the control element, which has such an angle with respect to the direction of movement of the control element.
With such a design, it is accordingly provided that the continued movement of the control element presses the actuating body in the direction of the coupling end position and finally into the coupling end position. If the control element is displaced in the opposite direction, this restores the freedom of movement of the actuating body and the actuating body can be pushed out of the coupling end position under the application of force by the ball bodies.
The two variants of the first coupling subdevice described here, i.e. the variant with a preferably pivotable manual control lever and the variant with an electric motor, can be designed with an identically dimensioned coupling socket. This makes it possible to couple the second coupling subdevice, which is preferably provided on the side of the tool, with both possible first coupling subdevices as desired.
In addition, a pneumatic variant of the first coupling subdevice is also conceivable, which also has the described coupling extension and the ball bodies and which permits displacement of the actuating body to the coupling end position by means of air pressure. A uniform second coupling subdevice could be coupled with all three variants of the first coupling subdevice.
This offers a high degree of flexibility in operation. For example, a robot where frequent tool changes are planned may use the electric or pneumatic variant, while on a robot that uses the same tool for a longer period of time, the manual variant with a manual control lever is appropriate. The tools, including the second subdevices attached to each of them, can be freely interchanged between the different robots. This reduces the overall requirement for tools to be kept available on the shop floor.
One further aspect therefore also relates to a system for manufacturing or handling workpieces using the described principle.
The system comprises at least two robots, each having at least one robot arm. Typically, the number of robots is greater than two. Ideally, all robots of the system, which are occasionally equipped with the same tools, are designed in the following manner.
The at least two robot arms of the at least two robots are each provided with a coupling subdevice which is designed for coupling at least one tool with a third coupling subdevice, so that the at least one tool can be coupled to each of the coupling subdevices of the at least two robot arms.
In the manner already described above, the coupling subdevices on the robot arms each have a coupling socket with a plurality of ball channels, within each of which a ball body being arranged, the ball bodies being movable between a radially extended coupling position and a radially retracted release position.
The coupling subdevices on the robot arms each have an internal actuating body which is displaceable relative to the coupling socket and which, in a coupling end position, presses the plurality of ball bodies into the radially extended coupling position, so that, interacting with a retaining edge on the inner side of the coupling recess of the coupling subdevice on the tool, the coupling subdevices on the robot arms can be coupled alternately to the at least one tool and the latter can be locked via the ball bodies.
The coupling subdevices on the robot arms represent at least two variants of the total of three variants of coupling subdevices, i.e. the variant with electric motor for displacement of the actuating body, the variant with manual control lever for displacement of the actuating body and the variant with pneumatic displacement of the actuating body.
In addition to the system in which at least two coupling subdevices with different types of actuation are used, a tool coupling device set is proposed which comprises the necessary coupling subdevices for such a system.
Such a tool coupling device set has at least three coupling subdevices, of which at least two coupling subdevices are intended for attachment to the distal end of a robot arm and of which a further coupling subdevice is intendedly attached to a tool which can be coupled to the robot arm.
The coupling subdevices for intended use at the end of the robot arm each have a coupling socket of the type already described for insertion into a coupling recess of the further coupling subdevice, ball channels provided there in which a ball body is provided, and an internal actuating body which can be displaced with respect to the coupling socket and which, in a coupling end position, presses the plurality of ball bodies into the radially extended coupling position.
The third coupling subdevice of the tool coupling device set represents the counterpart to the two coupling subdevices mentioned above. This third coupling subdevice has a coupling recess as well as at least one retaining edge for cooperating with the ball bodies, the ball bodies of the at least two previously mentioned coupling subdevices cooperating with this retaining edge to establish the coupled and locked state.
As already explained in the context of the
manufacturing or handling system, the at least two coupling subdevices are designed for intended use at the end of the robot arm for different types of actuation, wherein one of these coupling subdevices is designed for actuation by means of an electric motor and one of the coupling subdevices is designed for manual actuation, or wherein one of the coupling subdevices is designed for actuation by means of an electric motor and one of the coupling subdevices is designed for pneumatic actuation, or wherein one of the coupling subdevices is designed for manual actuation and one of the coupling subdevices is designed for pneumatic actuation.
Further advantages and aspects of the invention result from the claims and from the following description of preferred embodiments, which are explained below with reference to the figures.
The tool 120 is attached to the robot arm 110 by means of a tool coupling device 10, wherein this tool coupling device 10 comprises a coupling subdevice 20A on the robot arm side and a coupling subdevice 90 on the tool side. During operation, the coupling subdevices 20A, 90 are coupled and locked to each other.
If a different tool is required, the tool coupling device 10 permits easy changing. By means of an unlocking process explained below, the coupling subdevices 20A, 90 get in an unlocked state in which the tool together with the coupling subdevice 90 can be released from the robot arm 110 and its coupling subdevice 20A. Removal of the tool 120 may be performed manually. Preferably, however, the robot arm 110 is moved to the area of a tool magazine not shown, the tool 120 is placed in a receptacle, and then the unlocking and separation takes place there.
The wall of the coupling socket 30 is penetrated by a total of eight ball channels 32, in each of which a ball body 34 is arranged. The ball bodies 34 are arranged movably in the ball channels 32 in the radial direction. In the illustrated extended position, the ball bodies 34 are in their outer end position and in this state project beyond the outer contour of the coupling socket 30. In their retracted position, on the other hand, the ball bodies 34 are displaced inwards so that they do not project beyond the outer contour of the coupling socket 30 or project beyond it to a reduced extent.
The ball bodies 34 serve the purpose of locking the coupling subdevice 20A to the coupling subdevice 90. If the ball bodies 34 are in the radially outer end position and are secured there, a locked state is thereby established. If, on the other hand, the ball bodies 34 can be pressed radially inwards or radially inwards, this is the unlocked state in which the coupling subdevice 20A, 90 can be separated from one another.
In order to bring the ball bodies 34 into their radially extended position for the purpose of locking and to secure them there, an actuating body 40 is provided inside the coupling socket 30, which is displaceable in a direction of movement 2 parallel to the coupling direction 2. The actuating body 40 has a rotationally symmetrical actuating surface 42 which is divided into two cone section surfaces 42A, 42B having different angles of inclination with respect to the direction of movement 2.
When the actuating body 40 is displaced upwardly with respect to the orientation of
The displacement of the actuating body 40 in the direction of displacement 2 is effected in the case of variant 20A of
The control element 54 in turn interacts with the actuating body 40. As can be seen in particular from
The guide surfaces 58 are preferably angled such that displacement of the control element 54 cannot be achieved by application of force by the actuating body 40. Even if the ball bodies 34 are pressed inward with high force and if the actuating body 40 is pressed downward in response thereto, the control element 54 is prevented from being displaced horizontally as a result thereof by means of self-locking. Thus, if the electric motor 60 fails, the tool coupling device 10 is held in the locked state.
In the design of the coupling subdevice according to
However, in the case of this design, the displacement of the actuating body 40 is performed manually. For this purpose, a manual control lever 70 is provided on the outside of the housing 22. The manual control lever 70 is hinged to the outer side of the housing 22 so as to be pivotable about a pivot axis 4. The manual control lever 70 has a curved shape so that, in the applied state of
The state of
If the manual control lever 70 is swiveled outward from its position of
In the locked state of
In this case, however, the displacement of the actuating body 40 is effected pneumatically. Two compressed air ports 80A, 80B are provided on the outside of the housing 22 and communicate with two piston chambers 82A, 82B in the housing. These two piston chambers 82A, 82B are arranged on either side of a piston section 48 which is part of the actuating body 40. Since this design does not require a mechanical connection to a control element 54, a spring device 49 in the form of a centric helical compression spring may instead be arranged on the underside of the actuating body 40. This helical compression spring permanently presses the actuating body 40 upwards into that end position in which the ball bodies 34 are pressed outwards and the locked state is accordingly established.
If the coupling subdevice 20C is to be decoupled, this is done by applying air pressure to the piston chamber 82A via the compressed air port 80A. If the pressure is sufficiently high, this is sufficient to displace the actuating body 40 downwards against the force of the spring device 49, so that the ball bodies 34 can then be moved radially inwards again and the locked state is thereby released.
In accordance with the coupling subdevices 20A, 20B, 20C the coupling subdevice 90 has a housing 92 which, with reference to the orientation of
As
The second coupling subdevice 90 can also be coupled and locked to the other first coupling subdevices 20A, 20B as shown in
On this basis, the sets 200 of
The sets of
The set of
Since the tools 120A, 120B, 120C are each provided with coupling subdevices 90 of identical design, they are in interchangeable. Thus, each of the robots of
