EP4161741A1

EP4161741A1 - Gripper finger and gripper comprising gripper fingers of this type

Info

Publication number: EP4161741A1
Application number: EP21730496.3A
Authority: EP
Inventors: Martin Riedel; Till SCHULTE-REBBELMUND
Original assignee: KUKA Deutschland GmbH
Current assignee: KUKA Deutschland GmbH
Priority date: 2020-06-04
Filing date: 2021-05-27
Publication date: 2023-04-12
Also published as: WO2021244938A1; DE102020207035A1

Abstract

The invention relates to a gripper finger (1), comprising a transmission (5) which is designed to pivot the gripper finger (1) about a pivot axis (S) associated with the finger base element (2.1) and to curve the kinematic chain of the finger element (2) by pulling on the first pulling means (3), wherein the transmission (5) has a pivotally mounted first transmission element (5.1) that is connected to the first pulling means (3), and has a pivotally mounted second transmission element (5.2) that is connected to the finger base element (2.1), and the first transmission element (5.1) is coupled to the second transmission element (5.2) by means of a transmission coupler (6) in such a way that a pivoting of the gripper finger (1) is brought about with a common pivoting movement of the first transmission element (5.1) and the second transmission element (5.2), and, with a sole pivoting movement of the first transmission element (5.1) relative to the second transmission element (5.2), a pulling force is introduced into the first pulling means (3) and forwarded to the finger tip element (2.2) in order to bring about the curving of the gripper finger (1). The invention also relates to a gripper (14) comprising gripper fingers (1) of this type.

Description

Gripper fingers and grippers with such gripper fingers

The invention relates to a gripper finger, comprising a kinematic chain of several successive, mutually adjustable finger links, of which a proximal finger link in the kinematic chain forms a finger root link and a finger link dista les in the kinematic chain forms a fingertip link, and having at least a longitudinally extending first traction means along the kinematic chain of the fin gerglieder, which is connected to the fingertip member. The invention also relates to a gripper with such gripper fingers.

DE 102006 009 559 B3 describes a gripper device in the manner of an artificial hand with at least two fingers attached to a frame, of which at least one finger can be transferred from an elongated to a curved finger position along a plane of movement that can be assigned to the finger by means of an actuator is, wherein the finger is formed in one piece and has a longitudinal extension along which at least one area is provided around which the finger can be bent in the plane of motion assigned to it, the at least one area around which the finger can be bent in the plane of motion assigned to it is, is designed in a hinge-like manner that along the at least one actuator-bendable finger a tensile and compressive force-transmitting, elongated actuating element is provided with two actuating element ends, one of which is provided with an actuating element end with a fingertip area of the finger opposite the frame and the other end of the actuating element with the A ktor are integrally connected. The object of the invention is to provide a gripper finger and a gripper with at least one pair of such gripper fingers, each of which has a particularly reliable constructive structure and can still be used very flexibly for a wide variety of gripping requirements.

The object is achieved according to the invention by a gripper finger, comprising a kinematic chain of several consecutive, mutually adjustable fin gerbodiments, of which one in the kinematic chain proximal finger link forms a finger root link and a finger link distal in the kinematic chain a fingertip link forms, and having at least one longitudinally extending along the kinematic chain of the finger links first traction means, which is connected to the fingertip member, characterized by a transmission which is designed to pivot the gripper finger about a pivot axis assigned to the fingerwur zel member and to bend the kinematic tables Chain of the finger links by pulling on the first traction means, the transmission having a pivotably mounted first gear member which is connected to the first traction means and a pivotably mounted second gear member which is connected to the fingerw Root member is connected, and the first gear member is coupled to the second gear member by means of a gear coupling, such that a joint pivoting movement of the first gear member and the second gear member causes a pivoting of the gripper finger and a single pivoting movement of the first gear member relative to the second gear member Tensile force is introduced into the first traction means and passed on to the Fin gerspitzenglied to cause the crook of the Grei ferfingers. The gripper finger can, depending on the application, as a single gripper finger, in combination with fixed or movable other gripping elements or in combination with several according to the invention designed gripper fingers, for example in pairs or in the form of an anthropomorphic gripper hand who used the. Accordingly, the gripper finger can be used individually or in multiple designs as a component of a gripper. The gripper finger according to the invention can be used in particular for partially or fully automated robotic gripping tasks. In this respect, the gripper finger or a gripper that has one or more such gripper fingers can form a gripping tool that can be automatically handled, in particular moved and operated, by a robot arm in manual operation or program-controlled. The gripper finger can, in particular, be automatically pivoted and curved or stretched again in a program-controlled manner.

The finger joints of the gripper finger can be rigid individual members, analogous to the finger joints of a hand of a man. These phalanges are connected to each other via joints. To form an anthropomorphic finger, the phalanges can be connected in series, so that a rigid phalanx and a movable finger joint always alternate.

The several finger links and several finger joints accordingly form a kinematic chain of several successive, mutually adjustable finger joints. In principle, the gripper finger can have any number of phalanges and finger joints. A useful number of phalanges in most general cases can, for example, be between three fingers and twelve phalanges. The chain of several finger links and several finger joints has at one end a first end link which is the proximal finger link and in this respect forms a fingerwur zel member of the gripper finger. The finger root link can be that finger link with which the entire gripper finger is mounted, for example, on a base body of a gripper or a robot hand.

The chain of several finger links and several finger joints also has a second end link at the other end, which is the distal finger joint and in this respect forms a fingertip member of the gripper finger.

The longitudinally extending first traction means can be arranged within the enveloping surface of the gripper finger. The first train medium is based on the neutral fiber of the Grei ferfingers closer to the concave side of the curved Grei ferfingers. The first traction device can be a single single pull medium. Alternatively, the first traction means can be formed by two or more individual traction means. For example, two individual pulling means can be provided on a gripper finger, which run parallel to one another along the gripper finger at a distance from one another. The phalanges of the gripper finger can have openings, holes, open-edged recesses, grooves or grooves in which the first pulling means or the one or more individual pulling means are guided. The first traction means is designed to transmit at least tractive forces. In this respect, the traction means can be formed, for example, by ropes, cables, wires or cords. The first traction means can, however, optionally also be designed to transmit both tensile forces and compressive forces, this generally not being necessary, in particular not when other devices are provided to to bring the gripper finger back into its extended state, such as the return means described in more detail below. In order to transmit tensile forces and compressive forces, the first tensile means can be formed, for example, from flexurally elastic rods such as plastic strips, in particular made of polyamide.

In its most general embodiment, the transmission can be formed by any mechanical actuators, which include at least one transmission input member that is driven by a drive motor and is connected to the first traction mechanism and includes at least one transmission output member that is verbun with the root member of the gripper finger .

An actuator of the transmission, i.e. the transmission output element, is designed to pivot the gripper finger about a pivot axis assigned to the finger root element, and another actuator of the transmission, i.e. the transmission input element, is designed to bend the kinematic chain of the finger elements by pulling on the first traction mechanism. The one actuator and the other actuator are mechanically gekop pelt. The mechanical coupling of one actuator of the transmission with the other actuator of the transmission can take place in different ways, as will be described in more detail below with reference to different design variants.

In the basic embodiment, the gripper finger has a pivotably mounted first gear member which is connected to the first traction means and a pivotably gela Gertes second gear member which is connected to the fingerwur zel member. The first transmission link is included coupled to the second gear member by means of a gear coupling.

By the first gear member, the second gear member and the gear coupling are designed to cause a pivoting of the gripper finger with a common pivoting movement of the first gear member and second gear and to initiate a tensile force in the first traction means with a single pivoting movement of the first gear member relative to the second gear member and to forward to the fingertip member in order to cause the gripper finger to bend, the force and / or the pivoting position of the gripper finger can be defined up to which the gripper finger remains extended and the moment when the gripper finger begins to bend can be defined , in particular depending on the execution form of the gripper finger structurally variable given who the, depending on the training, setting, configuration and / or control of the gear coupling. The gear coupling determines in what way and to what extent or under what force the first gear member executes or executes a relative movement relative to the second gear member or can or does not execute or cannot execute. This determines the state of the gripper finger when a closing movement of the gripper finger in the extended state changes into a curved state of the gripper finger. Due to its mechanical properties, the gear coupling can structurally specify this transition area between the stretched gripper finger and the curved gripper finger. Alternatively, the transmission coupling can be designed to be variable, either in the form of discrete states or in the form of continuously changeable states, such as by means of a coupling or a torque converter, so that the transition area can be variably controlled. In a first embodiment, the gear coupling can have at least one spring means which is designed to couple the first gear member resiliently to the second gear member, such that by driving the first gear member due to the spring means, the coupled second gear member is also moved as long as the Driving force acting on the spring means does not exceed the spring force of the spring means.

A relative rotation of the first gear member with respect to the second gear member takes place here as a function of the spring stiffness of the spring means. The gripper finger is curved only when the first gear member is rotated relative to the second gear member. If the first gear member and the second gear member move uniformly, i.e. without a relative rotation of the first gear member with respect to the second gear member taking place, the gripper finger is not curved, but only pivoted around its finger root member.

In addition to the spring stiffness of the spring means, a relative rotation of the first gear member with respect to the second Ge gear member is also dependent on the rigidity of the gripper finger as such, that is, the rigidity that acts against bending of the gripper finger. This stiffness can result from the structural design of the phalanges of the gripper finger (internal stiffness) and / or can be set or specified by separate means that act against bending of the gripper finger, such as the second return means described in more detail below.

The gear coupling or the at least one spring means can be designed and / or set up to couple the first gear member to the second gear member in such a way that a torque transmitted from the first transmission element to the second transmission element continues to be transmitted to the second transmission element even after a predetermined threshold drive torque is exceeded, even if the second transmission element is at least essentially not moved further when the drive threshold torque is exceeded and only the first transmission element is moved further.

The torque that is transmitted from the first gear member to the second gear member is thus transmitted even after the direct coupling of the first gear member and the second gear member has been released, ie when the first gear member moves on by itself, without the second gear member, and can increase even further in this phase. If a further drive torque is exceeded, the force is transmitted to the traction device, which bends the gripper finger. The torque transmitted from the first transmission element to the second transmission element is retained or increases even further.

In the first phase the gripper closes. When the object to be gripped is touched, a second phase begins, at the beginning of which the coupling is released. As a result, the closing torque on the gripper finger or the gripper fingers increases further without the gripper fingers moving in a pivoting manner. From a further limit moment, there is a third phase in which the closing moment continues to exist or is increased even further, at the same time the gripper finger or the gripper fingers bend and wrap around the object. The additional torque increase in the second phase ensures that the gripper finger does not arch away from the object again. Arching away would happen if the gripper fingers were only closed over the traction mechanism would take place without the torque being transmitted to the second transmission element even after the predetermined drive threshold torque has been exceeded.

The spring force of the spring means can be set to move the first gear member and the second gear member together in the case of driving the first gear member below a predetermined drive threshold torque, and to move the first gear member alone in the case of driving the first gear member above the predetermined drive threshold torque to move, wherein the second gear member is not moved further because at least substantially.

This has the consequence that the gripper finger remains at least essentially in a stretched state while driving the first gear member below a given drive threshold torque and only bends when the drive threshold torque of the gripper fingers is exceeded.

The gear coupling can alternatively or in addition to a spring means have a coupling which is designed to rigidly connect the first gear member to the second gear member in its closed position and to release the rigid connection between the first gear member and the second gear member in its open position.

If the clutch is closed and the first gear member is rigidly connected to the second gear member, then the gripper finger is pivoted while maintaining its extended state when the drive motor drives the first gear member. If the clutch is opened and the rigid connection between the first gear member and the second gear member is released, then the gripper finger is opened. bends when the drive motor drives the first gear member.

A clutch can replace the spring means described above. Alternatively, the gripper finger can additionally be provided with such a coupling while retaining a spring means. A clutch has the advantage that the release torque of the clutch can be adjusted. Another advantage can arise if the clutch is designed to be controllable, i.e. if the clutch is activated electromechanically, for example, i.e. can be opened or closed as required. The switching of the gripper finger between its stretched state and its bendable state can be actively controlled.

In all embodiments, the first gear member can generally have a first disk sector with an arcuate first jacket wall, which forms at least one first guide channel for the at least one first traction device and / or a second disk sector with an arcuate second jacket wall that has a second guide channel forms for a second traction means which is set up to drive the first gear member.

The respective arc shape of the jacket wall of the first disk sector and / or of the second disk sector can have a freely selectable course. The course of the respective arcuate first jacket wall and / or second jacket wall can, however, also be in the shape of a circular arc. The arc shape of the first jacket wall can have a different course than the arc shape of the second jacket wall. The respective arch shape specifies the radius or the lever arm length which acts on the first traction device or the second traction device. If the first shell wall and the second shell wall have different arched shape, a desired translation can be achieved from the second traction means to the first traction means.

The gripper finger can generally have a drive motor and a cable winch driven by the drive motor, which is designed to exert a tensile force on a second tensile means constructed as a cable in order to drive the first gear element by means of the tensile force on the cable. In this respect, the same drive motor causes both the pivoting of the gripper finger in its extended state and the curvature of the gripper finger through a uniform train movement.

Other flexible traction means such as cables, wires or cords are also understood as rope. They can include un ferent materials, such as steel or plastic, especially polyamide. The gripper finger can have a first return means which is designed to bias the finger root member against the driven pivoting movement of the second gear member into an open position of the gripper finger.

If, for example, a drive motor of the gripper finger turns a cable winch in a direction opposite to the direction of pull, in which the second pulling means is wound down again, the first return means pulls the gripper finger or its finger root link back into an opening position, with the second pulling means thereby remains tense. The multiple successive, mutually adjustable finger links can be designed as a one-piece gripper finger body, with two adjacent finger links being connected via a film hinge-like web and the multiple webs one within the gripper. fingers Bil the longitudinal support column of the gripper finger.

In such an embodiment, each phalanx, with the exception of the root phalanx, have a preferably elastic hollow body which each forms a probe body with which the gripper finger rests in contact with an object to be gripped. The respective hollow body can be designed as a hollow cylinder, the cylinder axes each extending parallel to the pivot axis of the gripper finger. The pivot axis goes through the second gear member, which can also be formed in one piece with the finger root member.

Each hollow body can, for example, have two holes on the top and bottom, through which one of, for example, two first traction means is threaded. In such a case, in an assembled state, the first traction means lie within the contour of the phalanges or within the contour of the hollow bodies. Starting from the neutral fiber, which is defined by the film hinge-like webs, the hollow bodies extend in the direction of the object to be gripped and with such cross-sectional contours that the hollow bodies taper towards the object to be gripped. As a result, when the gripper finger is in an extended state, intermediate spaces are created between each two adjacent hollow bodies, which allow the gripper finger to bend.

Opposite the hollow body can extend on the other side of the neutral fiber or the webs, formed support bodies on the back, which are supported on one another in the extended state of the gripper finger. For this purpose, the support bodies can have flat, pressure-stable retaining wall panels on the outside. have sections which, in the extended state of the gripper finger, abut one another on the front side. The flat, pressure-stable support wall sections can, together with the film hinge-like webs which form the support column of the gripper fingers, form a box frame that is rigid in the opening direction.

At the upper end of the gripper finger, a forceps grip projection can be formed on the fingertip member. The tweezer grip projection can also have an inside throat which is designed for gripping rod-shaped objects on their jacket wall, and can also have a gripping edge which is designed to carry out the tweezer grip.

The gripper finger can have a second return means which is designed to preload the multiple successive finger members, which are mounted so that they can be adjusted relative to one another, against the tensile force of the first traction means in an extended position of the gripper finger.

For this purpose, the second return means can be designed, for example, as a rubber band-like cable pull. The second return means can be fixed on the one hand to the phalanx of the finger and on the other hand can be fixed to the phalanx of the fingertip. The fin gerglieder can have open-edged recesses or grooves on the back of their gripping surfaces, which when viewed together form a channel in which the second return means can be guided within the outer contour of the gripper finger.

The object is also achieved by a gripper, comprising a gripper main body, a drive motor arranged on the gripper main body and at least one pair of gripper fingers in each case according to one or more of the described ones Embodiments which are mounted on the gripper main body, wherein the first gear members of the at least one pair of gripper fingers are driven jointly by the drive motor.

The described gripper fingers according to the invention can, depending on the embodiment, eliminate the existing disadvantages of known grippers, such as, for example, soft grippers, parallel grippers or multi-actuated, anthropomorphic gripper hands. For example, the known rope-based soft grippers have so far only been of limited suitability for gripping small or flat objects. Gripping heavier objects with parallel surfaces that cannot be enclosed is also problematic. A required tight closing of the mostly pivoting gripper fingers has so far led to a rearing of the fingers on the object, so that only the fingertip rests on it. If the object is so small that the fingers are almost closed, or if the object is flat relative to the length of the finger, then with such grippers there is no further point of contact on the object with the finger and the gripping state can become unstable when gripping. The rolling up or rearing up of the fingers with known finger grippers results from the moment that arises from the tensile force of the rope and the distance to the bending fiber.

If the finger is only rotated on the lowest phalanx, only pressure forces on the back of the finger are transmitted. In such cases, the finger will always remain stretched and can grip smaller objects very well with a pair of tweezers. However, a stretched finger cannot encircle larger objects if the fingers no longer bend on their own. With the embodiments of gripper fingers according to the invention, various gripper hand configurations can be created, which represent a hybrid solution in which both small or flat objects can be gripped and larger, more voluminous objects can be gripped. This means that both precision or tweezers as well as power grips can be made possible.

The characteristic curling up or rearing up, as occurs with known finger grippers, can be significantly reduced or even completely prevented. The gripper according to the invention should also be very inexpensive to build, but still be able to grip a wide range of different Objek th.

The gripper finger according to the invention is based on a mechanical decoupling of the direct rope force in the finger from the introduction of force by the drive. This means that the finger position and the finger curvature are not forcibly specified by the drive, but are deflected in a targeted manner, for example, based on force or controlled. In contrast to the prior art, the pull rope, which runs through through bores in the finger segments to the fingertip, is not directly driven or pulled by a driven pulley, for example, but is attached, for example, on the input side to an arcuate intermediate rope pulley designed in particular as a segment of a circle. which in turn can be rotated or pivoted, preferably and essentially chen in the pivot point of the finger. Such an intermediate rope pulley, as well as other intermediate rope pulleys of other fingers, can be actuated at the same time by a common drive. This can be done for example by means of a second rope or by means of an example Worm gear stage, such as an intermediate cable pulley with worm gear teeth and an internal worm shaft, can be implemented.

In a first embodiment, the rope of the finger can be connected to the intermediate rope pulley in such a way that it is only taken along after a certain rotational angular movement of the intermediate rope pulley, for example after 10 °, in particular 30 ° or 45 ° of free rotation, and the finger then ge bends. During the entire finger movement, i.e. also in this freely movable phase, however, the intermediate cable disk can transfer a moment to the first, proximal segment of the finger. For this purpose, the intermediate cable disk and the finger base can be resiliently connected to one another in such a way that a finger-closing torque is always transmitted by the drive when the gripper is actuated. In this decoupling phase, this moment on the finger base is transmitted as pressure forces via the contact surfaces of the segments on the back of the finger to the fingertip and keeps the finger stretched when the object comes into contact. If the intermediate rope pulley exceeds the decoupled area, the rope is pulled in the finger and the finger wraps itself around the component, but with an additional stabilizing moment.

The torque transmitted from the intermediate cable pulley to the finger base should in this case be present from the start and run constantly, which is possible, for example, with a pretensioned spring with a flat characteristic curve. Particularly advantageous in terms of design are, for example, band-like springs, in particular rubber bands, which run, for example, in an arcuate groove on the intermediate cable pulley. The finger can be extended to its starting position, for example, either via an integrated spiral spring or via a tension spring. The tension spring can in particular be a rubber band which runs on the back of the finger in the area of the contact surfaces of the segments and connects the fingertip with the finger base, ie the finger root member.

In addition to the finger base, this tape can also be connected to the frame of a gripper. The band can not only cause the fingers to stretch, but also cause the fingers to be pivoted outwards.

This structure can be very advantageous as it has a stabilizing effect and noticeably reduces premature or excessive bending of the fingers even with higher gripping force.

A second variant can make it possible, up to a defined force, to first perform a precision grip with stretched fingers and then switch to a shape-adaptive power grip, i.e. a loop grip.

In this variant, the pull rope of the finger is connected directly, ie without a tow rope or decoupled to the intermediate rope pulley. In addition, in this case, the intermediate cable pulley is temporarily firmly connected to the finger base and can fully transfer the required finger-stretching moment to the finger. This coupling is force-dependent and can be suddenly separated or continuously reduced. Versions with non-positive snap hooks or magnetic connections between disk and finger, that is, all types of couplings, are advantageous. This initially makes the finger for the tweezer grip held stretched. After the force-controlled release, for example the magnetic connection, the finger can encircle the object. In contrast to the first variant, enclosing the second variant is free, ie not against a tensioned spring, which means that the drive force is better converted into the wrapping force, but without an additional stabilizing effect in this phase.

A third variant combines the first and second variant by using both the coupling coupling, for example the magnetic coupling, and the spring preload, for example by means of a ribbon spring, between the intermediate cable disk and the finger base.

In a basic variant, the fingertip has a contact surface that is clearly rounded in the distal direction, which enables additional bracing of the last finger element with the object. However, if flat objects lying flat on a surface are to be gripped, this is not possible with the basic geometry of the finger. This can be remedied by an optional additional distal, slightly offset fingertip extension that acts like a fingernail and picks up the flat object with its sharp edges and, for example, holds it in a concave recess. This handle and the gripping element extension work well in combination with the design variants presented and also expand the range of tangible objects. The fingertip extension, ie the fin gerspitzenaufsatz is positioned offset so that it does not touch the object when the fingers are bent to enclose the object. The distal contact is made by means of the rounded fingertips. The structure described with only one essentially centrally located drive, including the various performance variants, can be used for a gripper structure with two as well as with several, in particular three or four, fingers arranged centrally.

In addition, two drives with four centric fingers can be used to control the opposite fingers in pairs. For example, cylindrical objects can be gripped laterally with two fingers by gripping the lateral surface of the cylindrical object on the shell side, or, for example, gripped with four fingers by overlapping an end face of the cylindrical object.

The individual fingers can be made up of individual segments that are articulately connected to one another, in particular via a spiral spring. The spiral spring acts as a central tendon around which the finger can bend forward as soon as the finger rope applies a tensile force to the distal segment. It can be provided that the finger cannot be bent backwards or only slightly. This can be prevented by means of contact surfaces in the shape of a segment of a circle, which can transmit a compressive force to the rear. Due to the special shape of the contact surfaces, forces can be transmitted both backwards and downwards without the finger segments being displaced relative to one another.

The finger segments can have the contact surfaces on the inside; these can preferably be rubberized. Additional support surfaces next to the contact surfaces can be used to hang the object on its edge or to support it in a stable manner, while the distal fingertip holds against it. The object is thus at least per finger clamped in two points. In one embodiment, the proximal segments are made longer in order to further intensify this effect.

An additional spring, in particular an elastic band, can run on the back of the finger, which always stretches the finger again when it is relaxed.

Another spring or another band can be arranged between the finger and the frame and has an opening effect and deflects the entire finger including the intermediate cable pulley, for example at least 45 °, in particular 60 ° or more than 80 °, so that larger objects can also be gripped.

Specific exemplary embodiments of the invention are explained in more detail in the following description with reference to the accompanying figures. Specific features of these exemplary exemplary embodiments can represent general features of the invention regardless of the specific context in which they are mentioned, possibly also viewed individually or in further combinations.

Show it:

Fig. 1 is a schematic representation of an exemplary gripper finger according to the invention in isolation in its extended state,

FIG. 2 shows a schematic representation of the inventive gripper finger according to FIG. 1 in isolation in its curved state. Fig. 3 is a schematic representation of an exemplary gripper with a pair of gripper fingers according to the invention according to FIG. 1 and a common drive motor,

Fig. 4 is a schematic representation of the example of the gripper according to FIG. 3 with the first traction means and the second traction means,

Fig. 5 is a schematic representation of the example of the gripper according to FIG. 3 with the first return means and the two-th return means,

6 shows a side view of a gripper finger formed in one piece according to FIG. 1 in isolation in its extended state,

FIG. 7 shows a perspective illustration of the one-piece gripper finger according to FIG. 6 in isolation in its extended state, and FIG

Fig. 8 is a perspective view of a gripper with a pair of fiction, contemporary gripper fingers according to FIG. 1 with a gripped object. An exemplary embodiment of a gripper finger 1 according to the invention is shown in FIGS. 1 and 2.

1 shows the gripper finger 1 in its extended state and FIG. 2 shows the gripper finger 1 in its curved state.

The gripper finger 1 has a kinematic chain of several successive, mutually adjustable gelager th finger links 2, of which a proximal finger link 2 in the kinematic chain forms a finger root link 2.1 and a finger link 2 distal in the kinematic chain forms a fingertip link 2.2.

In the case of the present exemplary embodiment, the gripper finger 1 has two first traction means 3 extending longitudinally along the kinematic chain of the finger links 2. The first two traction means 3 are connected to the fingertip member 2.2. The first traction means 3 are designed to transmit tractive forces. The first traction means 3 can be formed, for example, by ropes, cables, wires or cords. The finger members 2 of the gripper finger 1 can, as shown, openings 4 or alternatively holes, open-edged Aussparun gene, grooves or grooves in which the first Zugmit tel 3 are guided.

The gripper finger 1 also includes a gear 5, which is designed to pivot the gripper finger 1 about a pivot axis S assigned to the finger root link 2.1 and to bend the kinematic chain of the finger links 2 by pulling on the first traction means 3, the gear 5 being a pivotably mounted first Gear member 5.1, wel Ches is connected to the first traction means 3 and has a pivotably mounted second gear member 5.2, which is connected to the finger root member 2.1. The first gear member 5.1 is coupled to the second gear member 5.2 by means of a gear coupling 6, in such a way that when the first gear member 5.1 and the second gear member 5.2 swivel jointly, the gripper finger 1 is pivoted, and when the first gear member 5.1 swivels only relative to the second gear element 5.2 (FIG. 2) a tensile force is introduced into the first tensile means 3 and passed on to the fingertip element 2.2 in order to bring about the bending of the gripper finger 1.

In the case of the embodiment according to FIG. 1 and FIG. 2, the gear coupling 6 is designed as a spring means 6a, which is formed from coupling the first gear member 5.1 resiliently to the second gear member 5.2, such that by driving the first gear member 5.1, such as This especially re is shown in Fig. 3 by means of a drive motor 7, due to the spring means 6a and the coupled second Ge gear member 5.2 is moved as long as the drive force acting on the Federmit tel 6a does not exceed the spring force of the spring means 6a.

The spring force of the spring means 6a can be set to move the first gear member 5.1 and the second gear member 5.2 together in the case of driving the first gear member 5.1 by means of the drive motor 7 below a predetermined drive torque, and in the case of driving the first gear member 5.1 Above the predetermined drive threshold torque to move the first gear member 5.1 alone, the second gear member 5.2 being at least substantially not moved further, as is shown in particular in FIG. As can be seen in particular in FIG. 3, the first gear element 5.1 can have a first disk sector 8.1 with an arcuate first jacket wall 9.1 which forms at least one first guide channel 10.1 for the at least one first traction means 3. On a second disk sector 8.2, which has an arcuate second shell wall 9.2, a second guide channel 10.2 for a second traction means 11 can be formed out, which is set up to drive the first gear member 5.1.

The drive motor 7 has a motor shaft which carries a cable winch 12 driven by the drive motor 7. The cable winch 12 is designed to exert a tensile force on the second tensile means 11, which is constructed as a cable, in order to drive the first gear element 5.1 by means of the tensile force on the cable, i.e. to pivot it about the pivot axis S.

3 to 5 and 8 show a special embodiment of a gripper 14 according to the invention, having a gripper base body 13, the drive motor 7 arranged on the gripper base body 13 and, in the case of the present exemplary embodiment, exactly one pair of gripper fingers 1 according to the invention which are each pivotably mounted on the gripper base body 13.

As can be seen in particular from Fig. 4, in the first gear members 5.1 of the at least one pair of gripper fingers 1 of the drive motor 7 can be jointly exaggerated. For this purpose, two ropes, ie two second traction means 11, extend from the drive motor 7 and / or the cable winch 12, from each of which a rope or a second traction means 11 is guided to the respective first gear member 5.1 of the respective gripper finger 1. If the two second traction means 11 are wound up by means of the drive motor 7 and the cable winch 12 disgusting, the two gripper fingers 1 pivot towards one another and the gripper 14 accordingly executes a closing movement, the two gripper fingers 1 initially remaining in their respective extended state.

In order to reopen the two gripper fingers 1 against the closing movement, the gripper 14 can have a first return means 15.1 on each gripper finger 1, as can be seen in particular in FIG the driven pivoting movement of the second gear member 5.2 in an open position of the gripper fingers 1 pretension. So when the drive motor 7 lets the winch 12 rotate in an opposite direction, in which the two second traction means 11 are unwound again, the first return means 15.1 pull the gripper fingers 1 or the finger root members 2.1 back into an opening position, where the second traction means 11 remain tense.

The spring means 6a can also be seen in FIG. 5. In the exemplary embodiment presented, the spring means 6a are formed by rubber-band-like cables, which on the one hand (in Fig. 5 above) are fixed on the second gear member 5.2 or on a pin 16 also connected to the finger root member 2.1 and on the other hand (in Fig. 5 below) are each fixed on the first gear member 5.1, for example at a fixing point 17 of the first gear member 5.1, as shown for example in FIG. 1 and FIG. 2.

Fig. 5 also shows how the two gripper fingers 1 can each have a second return means 18, which is each designed that several successive, mutually adjustable finger members 2 against the tensile force of the first traction means 3 in a stretched position of the pretension the respective gripper finger 1. For this purpose, the respective second return means 18 can also be designed as a rubber band-like cable pull. The second return means 18 can be fixed on the one hand to the finger root member 2.1 and on the other hand to the fingertip member 2.2. The finger links 2 can have open-edged recesses 19 or grooves on the back of their Greifflä surfaces, which when viewed together form a channel in which the second return means 18 can be guided within the outer contour of the gripper finger 1.

FIGS. 6 and 7 each show the gripper finger 1 on their own. In this embodiment, the several successive, mutually adjustable fin gerglieder 2 are formed as a one-piece gripper finger body, each two adjacent finger members 2 are connected via a film hinge-like web 20 and the several webs 20 a longitudinally extending support column within the gripper finger 1 of the Form gripper finger 1.

Each finger phalanx 2, with the exception of the finger root phalanx 2.1, has a preferably elastic hollow body 21, which in each case forms a feeler body with which the gripper finger 1 is in contact with an object to be gripped. The respective ge hollow body 21 can be designed as a hollow cylinder, the cylinder axes each extending parallel to the pivot axis S of the gripper finger 1. The pivot axis S goes through the second gear element 5.2, which is also formed in one piece with the finger root element 2.1. The pins 16 are also integrally formed with the finger root member 2.1.

Each hollow body 21 has on the top and bottom (covered in FIG. 7) two holes 22 through which one each the two first traction means 3 is threaded through. Thus, in an assembled state, the first traction means 3 lie within the contour of the finger links 2 or within the contour of the hollow body 21. The hollow body 21 extend starting from the neutral fiber, which is defined by the film hinge-term webs 20, in Direction of the object to be gripped with such cross-sectional contours that the hollow bodies 21 taper towards the object to be gripped the gripper finger 1 can bend.

Opposite the hollow body 21 are on the other side of the neutral fiber or the webs 20 rear support bodies

23, which are supported on one another in the extended state of the gripper finger 1. To this end, the support body 23 has on the outside flat, pressure-stable support wall sections which, in the extended state of the gripper finger 1, abut one another at the front. The flat, pressure-stable support wall sections together with the film hinge-like webs 20 which form the support column of the gripper finger 1, a box frame biegestei fen in the opening direction.

At the respective upper end of each gripper finger 1 there is a tweezer grip projection on the respective fingertip element 2.2

24 molded. The tweezers grip projection 24 has in the case of the illustrated embodiment an inside throat 25 which is designed for gripping rod-shaped objects on their jacket wall, and a gripping edge 26 which is designed to carry out the tweezers grip. FIG. 8 shows the exemplary gripper 14 according to FIG. 5, how it clamps a circular cylindrical object 27 firmly on its jacket wall. The two gripper fingers 1 are curved around the circular cylindrical object 27 in order to hold it in place over a large area with radial clamping force. In order to achieve this, the two gripper fingers 1 are moved towards one another from their open positions, analogously to FIG. Then the clamping force increases without the gripper fingers 1 pivoting any further. When a drive threshold torque is reached, the gripper fingers 1 begin to curve and the hollow bodies by 21 of the finger links 2 successively rest against the one wall of the circular cylindrical object 27. In this case, additional radial holding forces are via the hollow body 21 of the

The phalanges 2 of the fingers are transferred to the circular cylindrical object 27.

Claims

1. Gripper fingers, having a kinematic chain of several successive finger links (2) which are adjustable against each other, of which a finger link proximal in the kinematic chain (2) forms a finger root link (2.1) and a finger link distal in the kinematic chain ( 2) a fingertip joint

(2.2) forms, and having at least one longitudinally stretching first traction means (3) along the kinematic chain of the finger links (2), which is connected to the finger tip member (2.2), characterized by a gear (5) which is designed for Pivoting the gripper finger (1) around one of the phalanx of the finger

(2.1) associated pivot axis (S) and for bending the kinematic chain of the finger links (2) by pulling on the first traction means (3), the gear (5) having a pivotably mounted first gear member (5.1), which with the first Traction means (3) is connected and a pivotably mounted second gear member

(5.2), which is connected to the finger root member (2.1), and the first gear member (5.1) to the second gear member by means of a gear coupling (6)

(5.2) is coupled in such a way that when the first gear member (5.1) and the second gear member (5.2) are swiveled together, the gripper finger (1) is swiveled, and when the first gear member (5.1) is only swiveled relative to the second Gear member (5.2) introduced a tensile force into the first traction means (3) and applied to the fingertip Zen link (2.2) is forwarded to cause the gripper finger (1) to bend.

2. Gripper finger according to claim 1, characterized in that the gear coupling (6) has at least one spring means (6a) which is designed to couple the first gear member (5.1) resiliently to the second gear member (5.2), such that by driving of the first gear member (5.1) due to the spring means (6a), the coupled second gear member (5.2) is also moved as long as the drive force acting on the spring means (6a) does not exceed the spring force of the spring means (6a).

3. Gripper finger according to claim 1 or 2, characterized in that the gear coupling (6) or the at least one spring means (6a) is formed and / or is directed, the first gear member (5.1) in such a way to the second gear member (5.2) to be coupled so that a torque transmitted from the first gear member (5.1) to the second gear member (5.2) continues to be transmitted to the second gear member (5.2) even after a predetermined drive threshold torque has been exceeded, even if the second gear member (5.2) is at least in the Essentially, it is not moved further and only the first gear element (5.1) is moved further.

4. gripper finger according to claim 2 or 3, characterized in that the spring force of the spring means (6a) is set, in the case of driving the first Ge gear member (5.1) below a predetermined drive threshold torque, the first gear member (5.1) and to move the second gear member (5.2) together and in the case of driving the first gear member

(5.1) above the predetermined drive threshold torque to move the first gear member (5.1) alone, the second gear member (5.2) not being moved further, at least essentially.

5. Gripper finger according to one of claims 1 to 4, characterized in that the gear coupling (6) has a coupling which is designed to rigidly connect the first gear member (5.1) to the second gear member (5.2) in its closed position and in its open position to release the rigid connection between the first gear member (5.1) and the second gear member (5.2).

6. Gripper finger according to one of claims 1 to 5, characterized in that the first gear member (5.1) has a first disk sector (8.1) with an arcuate first shell wall (9.1), the at least one first guide channel (10.1) for the at least one first train means (3) and / or a second disk sector

(8.2) with an arcuate second jacket wall (9.2) which forms a second guide channel (10.2) for a second traction means (11) which is set up to drive the first gear member (5.1).

7. Gripper finger according to one of claims 1 to 6, characterized in that the gripper finger (1) has a first return means (15.1) which is designed to move the finger root member (2.1) into an open position counter to the driven pivoting movement of the second gear member (5.2) of the gripper finger (1).

8. Gripper finger according to one of claims 1 to 7, characterized in that the multiple successive, mutually adjustable finger members (2) are designed as a one-piece gripper finger body, two adjacent finger members (2) connected via a film hinge-like web (20) and the plurality of webs (20) form a support column of the gripper finger (1) extending longitudinally within the gripper finger (1).

9. gripper finger according to one of claims 1 to 8, characterized in that the gripper finger (1) has a second return means (18) which is formed, the multiple successive, mutually adjustable bar mounted finger links (2) against the tensile force of the first Tensioning means (3) in a stretched position of the Grei ferfingers (1).

10. Gripper, comprising a gripper base body (13), a drive motor arranged on the gripper base body (13)

(7) and at least one pair of gripper fingers (1) each Weil according to one of claims 1 to 9, which are mounted on the gripper base body (13), wherein the first Ge gear members (5.1) of the at least one pair of gripper fingers (1) are driven jointly by the drive motor (7).