Gripping device, in particular robot hand, for a robot arm having at least two movable fingers and at least one drive unit for providing a drive force for moving the fingers, and method

Abstract

The invention relates to a gripping device (1), in particular a robot hand, for a robot arm, having at least two movable fingers (5a, 5b), at least one drive unit (10) for providing a drive force for moving the fingers (5a, 5b), and at least one switchable transmission unit (20) for selectively transmitting the drive force from the drive unit (10) to one or more fingers (5a, 5b).

Description

[0001] Gripping device, in particular robot hand, for a robot arm with at least two movable fingers and at least one drive unit for providing a drive force for moving the fingers and a method

[0002] The invention relates to a gripping device, in particular a robot hand, for a robot arm with at least two movable fingers and at least one drive unit for providing a driving force for moving the fingers. The invention further relates to a method for operating a gripping device, in particular a robot hand, for a robot arm with at least two movable fingers and at least one drive unit for providing a driving force for moving the fingers.

[0003] Background of the invention

[0004] Gripping devices are used particularly in conjunction with robot arms and offer significant benefits, for example, in industrial production lines. For instance, robot arms can be used to precisely position and subsequently assemble heavy components. To grip a component, especially a smaller one, such a robot arm requires a gripping device, which is typically designed as a hand or hand-like structure with multiple fingers or thumbs. A dedicated motor is typically used to actuate each finger, allowing each finger to move independently. This negatively impacts the complexity of the control system, the compactness of the gripping device, and, most importantly, its cost. Generally, a larger number of motors leads to increased costs.

[0005] The prior art describes a robotic hand in which several fingers are moved by means of a common motor, see “Toward Dexterous Manipulation With Augmented Adaptive Synergies: The Pisa / IT SoftHand 2”, Della Santina et al., IEEE Transactions on Robotics, Vol. 34, No. 5, October 2018. In this robotic hand, the fingers are connected by a force-transmitting cable. This cable is guided over several pulleys, so that actuation of the motor results in the movement of the multiple fingers. The disadvantage here is that the multiple fingers cannot be controlled completely independently of one another. The robotic hand requires complex control because the force transmission to the fingers essentially follows nonlinear relationships. Such nonlinear dynamic systems require a complex control algorithm. Disclosure of the invention

[0006] Against this background, the task arises to provide a cost-efficient gripping device with separately controllable fingers.

[0007] The problem is solved by a gripping device, in particular a robot hand, for a robot arm with at least two movable fingers and at least one drive unit for providing a drive force to move the fingers, wherein at least one switchable transmission unit for selectively transmitting the drive force from the drive unit to one or more fingers.

[0008] The gripping device according to the invention for a robot arm has at least two movable fingers. These movable fingers can be moved by means of at least one drive unit, wherein the drive unit can provide a driving force for moving the fingers. Furthermore, the gripping device according to the invention has at least one switchable transmission unit, wherein the switchable transmission unit enables the selective transmission of the driving force from the drive unit to one or more fingers. The advantage of the invention lies essentially in the fact that a smaller number of drive units can control one or more fingers and that these fingers can be selectively chosen by means of the switchable transmission unit. This represents a particularly cost-effective solution for a gripping device with separately controllable fingers.

[0009] The gripping device can be designed as an underactuated gripping device, in which the number of drive units is less than the number of movable fingers, or the number of degrees of freedom of all movable fingers. For example, exactly one drive unit can be provided and at least two, for example five, fingers. Alternatively, two drive units can be provided and at least three, for example five, fingers. The principles explained above and below are particularly applicable to any underactuated devices, which especially preferably perform a gripping function or similar.

[0010] The fingers of the gripping device can be single-segmented or multi-segmented. For example, a finger can comprise two or three finger segments or digits that are movable relative to one another, in particular pivotable. The finger segments can be connected to one another via joints. According to an advantageous embodiment of the invention, the switchable transmission unit has a coupling mechanism assigned to each finger, wherein the coupling mechanism can be switched such that a drive force can be transmitted from the drive unit to one or more fingers. Preferably, the coupling mechanism is arranged between the respective finger and the drive unit and can establish a connection, in particular a mechanical one, between the drive unit and the respective finger.The multiple coupling mechanisms can be selectively controlled such that one or more fingers can be moved by the drive force from the drive unit. Advantageously, the coupling mechanism can be switched in such a way that a clearly defined either a transmitting state or a non-transmitting state exists. Thus, the drive force can be selectively transmitted from the drive unit to one or more fingers, and the respective fingers can be moved separately via the drive unit.

[0011] According to an advantageous embodiment of the invention, the coupling mechanism comprises a clutch. Preferably, the clutch enables a releasable power transmission between the drive unit and the respective finger. The clutch can be designed as a mechanical clutch or as a releasable clamping device. The releasable clamping device can be switched such that the drive force can be transmitted.

[0012] According to an advantageous embodiment of the invention, a force transmission means is arranged between the coupling mechanism and the respective finger associated with it. The force transmission means is configured such that the drive force from the drive unit can be transmitted to the respective finger via the force transmission means. The force transmission means can preferably be designed as a belt, rope, or cable, and advantageously, the force transmission means enables the most linear force transmission possible. This allows for a less complex control of the gripping device. The key advantage of this embodiment of the invention is that the arrangement of the force transmission means can remain unchanged, and the force transmission is controlled solely via the coupling mechanism.The respective selected finger(s) to be moved can be controlled by means of the switchable transmission unit without changing the arrangement of the traction transmission means.

[0013] According to an advantageous embodiment of the invention, the traction force transmission means is arranged between an input-side deflection roller and an output-side deflection roller or an attachment point on the respective finger, wherein the input-side deflection roller is preferably mechanically connected to the coupling mechanism. The traction force transmission means can be tensioned between the output-side and input-side deflection rollers, preferably being a closed or endless traction force transmission means. Alternatively, the traction force transmission means can be connected via an input-side deflection roller to an attachment point on the respective finger, preferably being designed as an open element.

[0014] According to an advantageous embodiment, a clamping device is connected to the traction force transmission means. This advantageously makes it possible to increase the driving force that can be transmitted via the traction force transmission means and to avoid a reduced delay in the movement of the finger. The clamping device is preferably arranged such that the clamping force within the traction force transmission means is increased.

[0015] According to an advantageous embodiment of the invention, a locking mechanism is arranged between the input-side deflection roller and the coupling mechanism. The locking mechanism is configured such that a return movement of the respective finger can be blocked. A return movement can be described as a movement that opposes the movement introduced by the drive force when the drive force is no longer applied to the respective finger. The locking mechanism can advantageously prevent this by, for example, maintaining tension in the traction force transmission element after the coupling mechanism has been opened or the force transmission through the coupling mechanism has been interrupted. This enables the gripping device to grasp and hold objects. The locking mechanism can be controlled via the transmission unit and is, in particular, releasable.

[0016] Preferably, the locking mechanism is arranged between the coupling mechanism and the traction force transmission means. This configuration allows the coupling mechanism to interrupt the power transmission from the drive unit to the finger via the traction force transmission means, while simultaneously maintaining a traction force acting on the finger via the traction force transmission means.

[0017] According to an advantageous embodiment of the invention, the locking mechanism comprises a worm gear, a one-sided coupling, an auxiliary coupling, or a clamping device, wherein the locking mechanism is actuated, in particular, via the transmission unit. The one-sided coupling can transmit the drive force in only one direction, preferably transmitting the drive force from the drive unit to the traction force transmission element. In the other direction, the one-sided coupling can lock the power transmission, thus blocking a return movement. The worm gear, in particular the worm wheel, is preferably mechanically connected to the input-side deflection pulley. The worm gear can, in particular, be self-locking. The clamping device can comprise an electromagnet, wherein the clamping device can fix the traction force transmission element in such a way that a return movement is no longer possible.The auxiliary clutch can be connected to a stationary and rotationally fixed housing in such a way that the return movement of the respective finger can be locked. For this purpose, the auxiliary clutch can be mechanically connected to the input-side deflection roller and the stationary and rotationally fixed housing. In the open state of the auxiliary clutch, the input-side deflection roller is preferably rotatable. In the closed state of the auxiliary clutch, the rotation of the output-side deflection roller is preferably locked. The auxiliary clutch can be controlled by means of the switchable transmission unit.

[0018] According to an advantageous embodiment of the invention, the drive unit comprises a motor and at least one transmission. A first transmission of the drive unit, also called a primary transmission, can be directly connected to the motor, for example, directly to a drive shaft of the motor. A second transmission of the drive unit, also called a secondary transmission, can be provided alternatively or additionally to the primary transmission. The second transmission is preferably configured such that a torque or a drive force provided by the motor can be coupled into the transmission unit.

[0019] The motor is preferably an electric motor. The first transmission is preferably designed as a gear transmission, for example as a planetary gear transmission.

[0020] The second transmission can be designed as a gear transmission. For example, a first gear of the gear transmission can mesh with a second gear of the gear transmission, wherein the second gear is rotationally fixed to an element of the switchable transmission unit, for example, a coupling mechanism, in particular a clutch, of the transmission unit.

[0021] The second transmission can alternatively be designed as a screw drive. The screw drive can have a rotatable but axially fixed threaded spindle and a slide movable axially along the threaded spindle. The slide can be configured to interact with the coupling mechanism of the switchable transmission unit, for example, to couple the movement of the slide with the traction force transmission element. The coupling mechanism can be designed as a clamping device by which the traction force transmission element can be clamped to the movable slide. The clamping device can include an electromagnet. Additionally, the switchable transmission unit can have an auxiliary clutch and / or a clamping device.

[0022] According to an advantageous embodiment of the invention, the gripping device comprises a further drive unit and a further switchable transmission unit for selectively transmitting an additional drive force from the further drive unit to one or more fingers. The further drive unit can have the same advantageous configurations and technical functions as the drive unit. The further drive unit is preferably connected to the traction force transmission means in such a way that it increases the clamping force in the traction force transmission means or enables a return movement of one or more fingers. For this purpose, the further drive unit can provide an additional drive force, which can selectively be transmitted from the further drive unit to one or more fingers via a further switchable transmission unit.The additional switchable transmission unit can comprise a switchable clutch and, in particular, a gear stage. The additional switchable transmission unit can have the same advantageous configurations and technical effects as the switchable transmission unit.

[0023] According to an advantageous embodiment of the invention, a finger comprises several finger segments, at least one joint arranged between two of the multiple finger segments, and, in particular, at least one return mechanism. A finger can consist of several finger segments and joints. The finger segments are preferably movable relative to one another via the joints. A return mechanism is particularly preferably arranged between the finger segments, especially at the joint, wherein the return mechanism can force a return movement of the finger and / or the finger segments.

[0024] According to an advantageous embodiment of the invention, the return mechanism comprises a spring, the spring being arranged between two finger segments in such a way that the spring provides a return force that opposes the driving force of the drive unit. The spring(s) can be tensioned by the movement of the finger, and the tension can induce a spring force in the respective spring, which generates a return force. Advantageously, the return force can enable a return movement without, for example, having to reverse the direction at the drive unit.

[0025] In an alternative embodiment of the invention, the additional drive unit can generate the restoring force and the restoring movement. For this purpose, the additional drive unit can, for example, pull the traction force transmission means in the opposite direction.

[0026] In a further embodiment of the invention, the gripping device comprises a control unit, which controls the drive unit. The control unit can selectively control the drive unit and preferably control the drive unit, and thus also the movable fingers, using different control modes. The movement of the drive unit can be transmitted to the movable fingers. Consequently, a specifically controlled drive unit can simultaneously control specifically controlled fingers. Additionally, the control unit can control the switchable transmission unit and, through the simultaneous selective control of the drive unit, generate a controlled, specific movement of the fingers. For example, the control unit can control the drive unit in such a way that the drive unit executes a stationary sinusoidal movement, particularly at a high frequency.

[0027] A further object of the invention is a method for operating a gripping device, in particular a robot hand, for a robot arm with at least two movable fingers, at least one drive unit for providing a drive force for moving the fingers, and a switchable transmission unit for selectively transmitting the drive force from the drive unit to one or more fingers, comprising the following method steps: a. Setting a switching position of the switchable transmission unit (20) such that the drive force can be transmitted from the drive unit (10) to one or more fingers (5a, 5b); b. Moving the one or more fingers (5a, 5b).

[0028] The method according to the invention can achieve the same technical effects, advantages and configurations as have already been described in connection with the gripping device.

[0029] According to an advantageous embodiment of the invention, the switchable transmission unit comprises a coupling mechanism assigned to each finger, wherein the transmission unit switches the coupling mechanism so that a driving force is transmitted from the drive unit to one or more fingers.

[0030] Further details and advantages of the invention will be explained below with reference to the exemplary embodiment shown in the drawings. This shows:

[0031] Fig. 1 shows a first embodiment of a gripping device according to the invention in a schematic, perspective view;

[0032] Fig. 2 shows a second embodiment of a gripping device according to the invention in a schematic, perspective view;

[0033] Fig. 3 shows a schematic power-time diagram for controlling the gripping device according to the invention;

[0034] Fig. 4 shows a third embodiment of a gripping device according to the invention in a schematic, perspective view;

[0035] Fig. 5 shows a fourth embodiment of a gripping device according to the invention in a schematic, perspective view;

[0036] Fig. 6 shows a fifth embodiment of a gripping device according to the invention in a schematic, perspective view; and

[0037] Fig. 7 shows a sixth embodiment of a gripping device according to the invention in a schematic, perspective view.

[0038] Fig. 1 shows a first embodiment of the gripping device 1 according to the invention. Such a gripping device 1 is preferably used as a robot hand. In this first embodiment, the gripping device 1 for a robot arm has two fingers 5a, 5b. Furthermore, the gripping device 1 has a drive unit 10 and a switchable transmission unit 20. The switchable transmission unit 20 is connected to each finger 5a, 5b via a traction force transmission element 3a, 3b.

[0039] The drive unit 10 can provide a driving force to move the fingers 5a, 5b, wherein the movement is a pivoting movement, and the maximum deflection of the finger 5a, 5b with the angle 0 mThe drive unit 10 is designated ax. To generate the driving force, the drive unit 10 comprises a motor 11 and a first gearbox 12. The first gearbox 12 drives a drive shaft 13, on which a second gearbox is arranged at each finger 5a, 5b. Each second gearbox includes an input gear 14a, 14b and an output gear 21a, 21b, which meshes with the input gear 14a, 14b. The respective output gear 21a, 21b is rotationally fixed to a first output shaft 22a, 22b of the transmission unit 20 and drives it.

[0040] According to the invention, the transmission unit 20 is switchable, so that the drive force of the drive unit 10 can be selectively transmitted to the respective finger 5a, 5b or not. For this purpose, the switchable transmission unit 20 comprises a coupling mechanism assigned to each finger 5a, 5b, which is configured as a clutch 23a, 23b. The coupling mechanism is switchable such that a drive force can be transmitted from the drive unit 10 to one or more fingers 5a, 5b. The clutch 23a, 23b can establish a mechanical connection between the first output shaft 22a, 22b and a second output shaft 24a, 24b. On the second output shaft 24a, 24b an input-side deflection pulley 2a, 2b is arranged, which establishes a connection to the traction force transmission means 3a, 3b, for example a belt, rope or cable, and thus enables the power transmission to the finger 5a, 5b.The traction force transmission means 3a, 3b is arranged between the coupling mechanism, here a coupling 23a, 23b, and the respective finger 5a, 5b associated with it, wherein the traction force transmission means 3a, 3b is configured such that the drive force from the drive unit 10 can be transmitted to the respective finger 5a, 5b by means of the traction force transmission means 3a, 3b. The traction force transmission means 3a, 3b is arranged between the input-side deflection pulley 2a, 2b and an output-side deflection pulley 4a, 4b. The respective finger 5a, 5b is arranged directly on the output-side deflection pulley 4a, 4b, so that the finger 5a, 5b can be deflected by a rotation of the deflection pulley 4a, 4b. The coupling 23a, 23b enables the selective transmission of the drive force from the drive unit 10 to the finger 5a, 5b and the interruption of the power transmission.In this gripping device 1, the drive unit 10 can selectively move one or more fingers 5a, 5b simultaneously. Due to the power transmission via gear drives and the traction force transmission means 3a, 3b guided by the deflection pulleys, a substantially linear power transmission can be provided. The fingers 5a, 5b can be controlled separately via the drive unit 10, thus saving costs, particularly for additional drive units.

[0041] Fig. 2 shows a second embodiment of the gripping device 1 according to the invention, wherein the drive unit 10 and the switchable transmission unit 20 are identical to those of the first embodiment. The essential differences between the first and the second embodiment of the gripping device 1 lie in the traction force transmission means 3a, 3b, as well as a further drive unit 10' and a further transmission unit 20'.

[0042] The additional drive unit 10' and the additional transmission unit 20' are preferably identical in construction to the drive unit 10 and the transmission unit 20. Thus, the additional drive unit 10' and the additional transmission unit 20' can have the same designs, technical effects and advantages as the drive unit 10 and the transmission unit 20.

[0043] The additional drive unit 10' can provide a further drive force via the additional switchable transmission unit 20'. For this purpose, the gripping device 1 has the additional switchable transmission unit 20' for selectively transmitting the additional drive force from the additional drive unit 10' to one or more fingers 5a, 5b. The additional transmission unit 20' preferably has a coupling mechanism, in particular a switchable clutch. The coupling mechanism can be switched by the additional switchable transmission unit 20' so that a force transmission is carried out or that the transmission of the additional drive force is interrupted. It is conceivable that the additional drive force and the drive force act simultaneously on one finger 5a, 5b, on different fingers 5a, 5b, or only one of them acts on one or more fingers 5a, 5b.

[0044] Another difference lies in the open traction force transmission means 3a, 3b. According to the first embodiment, the traction force transmission means 3a, 3b is closed or endless and arranged between the input-side deflection pulley 2a, 2b and the output-side deflection pulley 4a, 4b. According to the second embodiment, the traction force transmission means 3a, 3b is open. In Fig. 2, the traction force transmission means 3a, 3b, in particular its two ends, is attached to the input-side deflection pulley 2a, 2b of the switchable transmission unit 20 and to the input-side deflection pulley 2a', 2b' of the further switchable transmission unit 20'; specifically, the ends of the traction force transmission means 3a, 3b are attached to the respective input-side deflection pulleys 2a, 2b, 2a', 2b'.Between the respective input-side deflection pulleys 2a, 2b, 2a', 2b', the output-side deflection pulley 4a, 4b is arranged, wherein the traction force transmission means 3a, 3b is guided around the output-side deflection pulley 4a, 4b such that the output-side deflection pulley 4a, 4b can rotate in both directions about a rotational axis. Thus, the multiple fingers 5a, 5b can be rotated in both directions by the drive force and the additional drive force. Consequently, it is conceivable that the additional drive unit 10' adjusts the respective finger(s) 5a, 5b counterclockwise and the drive unit adjusts the respective finger(s) 5a, 5b clockwise, or vice versa.

[0045] Furthermore, it is conceivable that the additional drive unit 10' serves solely as a tensioning device. If the force transmission element 3a, 3b is designed, for example, as a rope, cable, or belt, it is advantageously necessary that the force transmission element 3a, 3b be kept under tension for direct force transmission. Depending on the application, the additional drive unit 10' can apply, increase, or decrease the tension on the respective force transmission element. Advantageously, the response behavior of the respective finger 5a, 5b can thus be adjusted.

[0046] Fig. 3 shows a schematic control of several fingers 5a, 5b, 5c. Fig. 3 shows an output value P on the Y-axis, several time steps t on the X-axis, and a maximum output value Pmax. The output value P can be specified by the drive unit 10 and the switchable transmission unit 20 and can, for example, represent the position or angular position of the respective finger 5a, 5b, 5c. Alternatively or additionally, the force applied to finger 5a, 5b, 5c can be controlled. For this purpose, the speed and torque of the motor 11 and the voltage on the traction force transmission element 3a, 3b are controlled. As described above, the switchable transmission unit 20 can selectively transmit the drive force from the drive unit 10 to one or more fingers 5a, 5b, 5c simultaneously.

[0047] Figure 3 clearly shows that a single finger 5a, 5b, 5c or multiple fingers 5a, 5b, 5c can be controlled individually or in parallel. Furthermore, Figure 3 shows that if different fingers 5a, 5b, 5c are controlled simultaneously, they are controlled with the same amplitude or output value. Alternatively, it is conceivable that different gear stages in the respective gearboxes are used for different fingers 5a, 5b, 5c to provide different gear ratios. This can lead to fingers 5a, 5b, 5c being controlled with different output values ​​or amplitudes, even though they are moved simultaneously.

[0048] For example, time steps 1 and 6 show that only finger 5a is controlled. In magazines 2, 3, and 5, two fingers are controlled in each magazine. In magazine 4, three fingers 5a, 5b, and 5c are controlled simultaneously. Furthermore, Fig. 3 shows that a reversal of the output value is possible. In magazines 5 and 6, the fingers are moved in the opposite direction. This reversal can preferably be achieved via the additional drive unit 10'.

[0049] Fig. 4 shows a third embodiment of the gripping device 1 according to the invention. In contrast to the first and second embodiments, the third embodiment has a finger 5a, 5b which comprises several finger segments 50a, 50b, joints 51a, 51b, and return mechanisms 52a, 52b. The joints 51a, 51b are each arranged between two finger segments 50a, 50b and preferably allow the two finger segments 50a, 50b to be movable independently of each other. Furthermore, it can be seen that one finger segment 50a, 50b is arranged on the output-side deflection roller 4a, 4b. Thus, the traction force transmission means 3a, 3b can be arranged essentially parallel to the finger 5a, 5b. Consequently, the finger 5a, 5b can contract essentially due to the driving force and replicate a closing finger movement.

[0050] The traction force transmission means 3a, 3b can be guided along the finger segments 50a, 50b via the joints 51a, 51b and attached to the joints 51a, 51b and / or the finger segments 50a, 50b. Each finger segment 50a, 50b can have an attachment point for the traction force transmission means. Figure 4 further shows that a return mechanism can be arranged along the joints 51a, 51b between two finger segments 50a, 50b. The return mechanism comprises, in particular, a spring 52a, 52b, wherein the spring 52a, 52b is arranged between two finger segments 50a, 50b such that the spring 52a, 52b has a return force that acts against the drive force from the drive unit 10. A finger 5a, 5b can thus straighten itself again after an interruption of the driving force. The springs 52a, 52b generate a restoring movement in the respective finger segments 50a, 50b.

[0051] Furthermore, Fig. 4 shows that a locking mechanism is arranged between the input-side deflection roller 2a, 2b and the coupling mechanism, here a coupling 23a, 23b, wherein the locking mechanism is configured such that a return movement of the respective finger can be blocked. In the present embodiment, the locking mechanism is designed as a one-sided coupling 25a, 25b. The one-sided coupling 25a, 25b preferably allows the transmission of the drive force from the drive unit 10 in the direction of the finger 5a, 5b, but not in the other direction. The locking mechanism or the one-sided coupling 25a, 25 is arranged on the second output shaft.

[0052] Fig. 5 shows a fourth embodiment, which differs from the third embodiment only by a different locking mechanism. In the fourth embodiment, a worm gear is used as the locking mechanism, which can be switched via the transmission unit 20. The worm gear has a worm wheel 27a, 27b and a worm 26a, 26b. Preferably, the worm 26a, 26b is arranged on the output shaft, in particular the second output shaft, behind the clutch 23a, 23b. The worm wheel 27a, 27b is mechanically connected to the input-side deflection pulley 2a, 2b, so that movement of the worm wheel 27a, 27b leads directly to the power transmission to the traction force transmission means 3a, 3b. A worm gear can be self-locking in one direction, and this can be used as a locking mechanism.

[0053] The embodiments shown in Figs. 6 and 7 differ from the previously shown embodiments by a different drive unit 10 and a different coupling mechanism. The fifth and sixth embodiments each show a drive unit 10 with a second gearbox designed as a screw drive. The screw drive comprises a threaded spindle 15 and a movable slide 16. Furthermore, a guide element 17 is provided for the movable slide 16.

[0054] Fig. 6 shows the switchable transmission unit 20, the traction force transmission means 3a, 3b, the fingers 5a, 5b, and the movable slide 16. For power transmission, the coupling is designed as a clamping device. Fig. 6 shows two first clamping devices 33a, 33b and two second clamping devices 34a, 34b, with only the first clamping devices 33a, 33b serving to transmit power to the fingers 5a, 5b. The clamping devices 33a, 33b, 34a, 34b preferably each have an electromagnet which can be actuated such that the traction force transmission means 3a, 3b can be clamped between the first and / or the second clamping device 33a, 33b, 34a, 34b. Thus, the movement of the movable carriage 16 can be transmitted via the traction force transmission means 3a, 3b to the fingers 5a, 5b or locked.

[0055] Preferably, the first clamping device 33a, 33b is arranged on the movable slide 16. Furthermore, the tensile force transmission means 3a, 3b each have a clamping device 30a, 30b, which can function as a fastening point for the tensile force transmission means 3a, 3b.

[0056] The second clamping device 34a, 34b can serve as a locking mechanism and selectively clamp the tensile force transmission means 3a, 3b in a fixed position. A return movement of the respective finger(s) 5a, 5b is then no longer possible. Electromagnets for use within the first and second clamping devices 33a, 33b, 34a, 34b are particularly advantageous because they are easy to control and release.

[0057] Fig. 7 shows a sixth embodiment of the gripping device 1 according to the invention, which has a similar structure to the fifth embodiment. The essential difference lies in the fastening of the traction force transmission means 3a, 3b and the locking mechanism. In addition to the first clamping device 33a, 33b, the switchable transmission unit 20 has an additional coupling 28a, 28b for each finger 5a, 5b. The additional coupling 28a, 28b is mechanically connected to the input-side deflection roller 2a, 2b of the respective traction force transmission means 3a, 3b. Furthermore, the additional coupling 28a, 28b is fixed to the housing 29 in a positionally and rotationally fixed manner. This results in the input-side deflection roller 2a, 2b not being rotatable when the additional clutch 28a, 28b is closed, and therefore no drive force can be transmitted via the respective traction force transmission means 3a, 3b to the respective finger 5a, 5b.This is only possible when the auxiliary clutch 28a, 28b is open and the input-side deflection pulley 2a, 2b can rotate. Therefore, the auxiliary clutch 28a, 28b can serve as a locking mechanism. The auxiliary clutch 28a, 28b is preferably engaged via the switchable transmission unit 20. The clamping device 30a, 30b can exert tension on the traction force transmission element 3a, 3b.

[0058] Basically, the gripping device 1 is operated such that one or more fingers 5a, 5b are first selected to be moved. In a subsequent step, the transmission unit 20 switches such that the respective finger(s) 5a, 5b are moved by means of the drive force from the drive unit 10. For example, the transmission unit 20 can close the clutch 23a, 23b so that power transmission from the first output shaft 22a, 22b to the second output shaft 24a, 24b is possible. The drive force can be passed from the second output shaft 24a, 24b to the finger via the traction force transmission means 3a, 3b, so that the drive force pivots the finger, for example, into an angular position 0. Reference numeral list

[0059] 1 gripping device

[0060] 2 inlet-side deflection pulleys

[0061] 2' Input-side deflection pulley of the further drive unit

[0062] 3 Traction transmission devices

[0063] 4 output-side deflection pulley

[0064] 5 fingers

[0065] 10 Drive unit

[0066] 10' additional drive unit

[0067] 11 Engine

[0068] 12 gearboxes

[0069] 13 Drive shaft

[0070] 14 Input-side gear

[0071] 15 threaded spindle

[0072] 16 sleds

[0073] 17 Guide element

[0074] 20 transmission units

[0075] 20' additional transmission unit

[0076] 21 output side gear

[0077] 22 first output shaft

[0078] 23 Clutch

[0079] 24 second output shaft

[0080] 25 single-sided clutch

[0081] 26 snail

[0082] 27 worm gear

[0083] 28 Additional clutch

[0084] 30 clamping device

[0085] 33 first clamping device

[0086] 34 second clamping device

[0087] 50 finger segments

[0088] 51 joints

[0089] 52 Spring a a first element b a second element c a third element

[0090] 0 Angle position

[0091] P output value t time step

Claims

Patent claims 1. Gripping device (1), in particular robot hand, for a robot arm with at least two movable fingers (5a, 5b) and at least one drive unit (10) for providing a drive force for moving the fingers (5a, 5b), characterized by at least one switchable transmission unit (20) for selectively transmitting the drive force from the drive unit (10) to one or more fingers (5a, 5b).

2. Gripping device (1) according to claim 1 , characterized in that the switchable transmission unit (20) has a coupling mechanism assigned to each finger (5a, 5b) and the coupling mechanism is switchable in such a way that a drive force can be transmitted from the drive unit (10) to one or more fingers (5a, 5b).

3. Gripping device (1) according to claim 2, characterized in that the coupling mechanism comprises a coupling (23a, 23b).

4. Gripping device (1) according to one of claims 2 or 3, characterized in that a traction force transmission means (3a, 3b) is arranged between the coupling mechanism and the respective finger (5a, 5b) assigned to it, wherein the traction force transmission means (3a, 3b) is configured such that the drive force from the drive unit (10) can be transmitted to the respective finger (5a, 5b) by means of the traction force transmission means (3a, 3b).

5. Gripping device (1) according to claim 4, characterized in that the traction force transmission means (3a, 3b) is arranged between an input-side deflection roller (2a, 2b) and an output-side deflection roller (4a, 4b) or an attachment point on the respective finger (5a, 5b), wherein the input-side deflection roller (2a, 2b) is in particular mechanically connected to the coupling mechanism.

6. Gripping device (1) according to claim 5, characterized in that a locking mechanism is arranged between the input-side deflection roller (2a, 2b) and the coupling mechanism, wherein the locking mechanism is configured such that a return movement of the respective finger (5a, 5b) can be blocked.

7. Gripping device (1) according to claim 6, characterized in that the locking mechanism comprises a worm gear, a one-sided coupling (25a, 25b), an additional coupling (28a, 28b) or a clamping device (34a, 34b), wherein the locking mechanism is particularly actuable via the transmission unit.

8. Gripping device according to one of the preceding claims, characterized in that the drive unit (10) comprises a motor (11) and at least one gearbox (12, 14, 21).

9. Gripping device (1) according to one of the preceding claims, characterized in that the gripping device (1) has a further drive unit (10') and a further switchable transmission unit (20') for selectively transmitting an additional further drive force from the further drive unit (10') to the one or the several fingers (5a, 5b).

10. Gripping device (1) according to one of the preceding claims, characterized in that a finger (5a, 5b) has several finger segments (50a, 50b), at least one joint (51a, 51b) arranged between two of the several finger segments (50a, 50b) and in particular at least one return mechanism.

11. Gripping device (1) according to claim 10, characterized in that a finger segment (50a, 50b) is either arranged on the output-side deflection roller (4a, 4b) or that each finger segment (51a, 51b) has an attachment point for the traction force transmission means (3a, 3b), wherein the traction force transmission means (3a, 3b) is arranged along the finger segments (50a, 50b) and the joints (51a, 51b).

12. Gripping device (1) according to claim 10 or 11, characterized in that the return mechanism comprises a spring (52a, 52b), wherein the spring (52a, 52b) is arranged between two finger segments (51a, 51b) such that the spring (52a, 52b) has a return force which acts against the drive force from the drive unit (10).

13. Method for operating a gripping device (1), in particular a robot hand, for a robot arm with at least two movable fingers (5a, 5b), at least one drive unit (10) for providing a drive force for Moving the fingers (5a, 5b) and a switchable transmission unit (20) for selectively transmitting the driving force from the drive unit (10) to one or more fingers (5a, 5b), comprising the following procedure steps: a. Setting a switching position of the switchable transmission unit (20) such that the driving force can be transmitted from the drive unit (10) to one or more fingers (5a, 5b); b. Moving the one or more fingers (5a, 5b).

14. Method according to claim 13, characterized in that the switchable transmission unit (20) comprises a coupling mechanism assigned to each finger (5a, 5b), wherein the transmission unit (20) switches the coupling mechanism so that a driving force is transmitted from the drive unit (10) to one or more fingers (5a, 5b).

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