PROSTHETIC FINGER AND PROSTHETIC HAND WITH PROSTHETIC FINGER

Description

[0001] The invention relates to a prosthetic finger with an associated motor drive, via which the prosthetic finger can be pivoted relative to a chassis about a first pivot axis. The prosthetic finger comprises a finger element that is mounted on the chassis for pivoting about the first pivot axis and coupled to a support. The support is coupled to a drive element that can be coupled to the drive and is coupled to the support in a torque-transmitting manner. The invention also relates to a prosthetic hand with a prosthetic finger that is mounted on a chassis of the prosthetic hand.

[0002] Prosthetic fingers and hands replace missing or no longer existing fingers or hands. Both prosthetic fingers and hands mimic the human anatomy. Prosthetic hands typically have four prosthetic fingers, which are pivotally mounted in the connection area to the chassis about pivot axes oriented essentially parallel to one another. The prosthetic fingers may also have additional, essentially parallel, distal pivot axes on the finger elements to enable the formation of a fist. Prosthetic hands also have a thumb, which is also considered a finger. The thumb is an essential component of the human hand and makes it a universal tool with a wide range of movement options and degrees of freedom.The importance of the thumb lies in the fact that its position relative to the other fingers determines the various grip patterns. Important positions and stances are the opposition grip and the lateral grip. In dem

[0003] The opposition grip allows you to hold large objects and grasp smaller ones. The lateral grip is especially useful for flat objects, but is also used when placing the hand flat on a table, grasping a computer mouse, and the like.

[0004] The metacarpophalangeal joint of a natural hand is designed in the shape of a saddle joint. In prosthetic hands, the positions that can be achieved with this joint are often attempted using a combination of pivot joints that allow the base of the thumb to pivot about pivot axes oriented at an angle to one another. A first pivot joint about a first pivot axis controls the flexion and extension of the finger element of the thumb, which allows objects to be grasped and released. The finger element is moved in a palmar direction. The other joint enables abduction and adduction of the thumb, which enables different grip types such as the opposition grip and the lateral grip. The finger element of the thumb is moved into the respective opposition position or lateral position.

[0005] Active movements of prostheses are often controlled and initiated by myoelectric signals. Electrical signals generated in muscle cells are detected via electrodes and transmitted to a control device, which, after processing the signals and amplifying them if necessary, activates or deactivates a motor drive. The energy for the adjustment is provided by an energy storage device, particularly an accumulator. To achieve sufficiently high forces and speeds, the motor drive is coupled to the prosthetic finger, if necessary via downstream gear stages. Every movement of a prosthetic finger consumes energy that must be drawn from the energy storage device, although only a limited amount of energy is available in the energy storage device. A prosthetic hand with a drive is described, for example, in EP 2 125 091 B1.

[0006] A passive movement of the prosthetic finger or prosthetic hand occurs when the prosthetic finger or prosthetic hand is moved relative to the chassis or the prosthetic hand itself due to the action of external forces. Such movements are, for example, deliberately caused by the contralateral hand of the prosthetic wearer or by the application of compressive or tensile forces when using the prosthetic hand. Passive movements do not consume any energy from the energy storage device. If the prosthetic hand or prosthetic finger is elastically mounted, it will return to its original position once the external force is removed. Locking elements make it possible to maintain the prosthetic finger or prosthetic hand in a specific position after a passive movement, for example to hold a prosthetic finger in a folded or spread position.

[0007] US 2016 / 0 250 044 A1 relates to a gear locking mechanism for a hand prosthesis comprising a first internal gear and a second internal gear. The first internal gear is attached to a distal phalanx of a finger element. The second internal gear is attached to a proximal phalanx of the finger element. An external gear is coupled to a knob and forms a bridge between the first internal gear and the second internal gear to lock a joint of the finger element. A spring is configured to return the knob to a locked position.

[0008] DE 10 2008 056 520 A1 relates to a finger element comprising a support component, a first phalanx with a first articulated connection to the support component, and a second phalanx with a second articulated connection to the first phalanx. A coupling mechanism is arranged between the first and second articulated connections. An actuator for the first articulated connection comprises a motor with a drive shaft and a worm gear with a threaded worm and a toothed segment engaging the threaded worm. The threaded worm is mounted on the drive shaft in a form-fitting manner for axial movement and is guided axially by separate guides.

[0009] US 2016 / 235554 A1 relates to a hand prosthesis system with multiple finger prostheses and a thumb prosthesis. The hand prosthesis system includes a thumb drive mechanism for actuating the prosthetic thumb, which is configured to allow the prosthetic thumb to perform a clamping or grasping movement and a release movement. The hand prosthesis system also includes a lock to maintain the clamping or grasping pressure after a motor is turned off. A finger joint can be locked via a gear lock. The prosthetic hand system may also include an adaptive grasping joint, which may be located on each prosthetic finger. The adaptive grasping joint is configured to passively adapt the plurality of prosthetic fingers to one or more differently shaped objects.

[0010] DE10 2005 061 313 A1 relates to a hand prosthesis comprising a chassis on which several finger prostheses are articulated. These finger prostheses are movable relative to the chassis and toward each other about at least one pivot axis via a drive. The force transmission devices are coupled to the finger prostheses via a common drive in such a way that, starting from a rest position and depending on the direction of rotation of the drive, at least two finger prostheses move through different adjustment angles relative to the chassis.

[0011] EP 2 653 137 A1 relates to a wrist prosthesis with a metacarpal and an attached thumb and index finger, which can be moved about a pivot axis. The thumb can be rotated about an adduction axis by driving transmission means via an electric motor integrated into the prosthesis. A rotating main element is also actuated via the electric motor. The transmission means are designed to substantially selectively control the thumb and index finger. The transmission means are designed such that a first angular movement of the rotating main element produces a significant rotation of the index finger between a closed and an open position, while the thumb remains locked during the first angular movement.

[0012] The object of the present invention is to provide a prosthetic finger and a prosthetic hand that can be used for a longer period of time without the need to recharge an energy storage device.

[0013] This object is achieved by a prosthetic finger or hand having the features of the independent claims. Advantageous embodiments and further developments of the invention are disclosed in the dependent claims, the description, and the figures.

[0014] The prosthetic finger, which is assigned a motor drive via which the prosthetic finger can be pivoted relative to a chassis about a first pivot axis, has a finger element that is mounted on the chassis for pivoting about the first pivot axis and is coupled to a carrier, wherein the carrier is coupled to a drive element that can be coupled to the drive and is coupled to the carrier in a torque-transmitting manner. The drive element is coupled to the carrier in a torque-transmitting manner via a coupling element, wherein the coupling element is mounted on the carrier in an axially displaceable manner and is elastically preloaded in the direction of the drive element. The prosthetic finger is designed in particular as a prosthetic thumb, wherein the finger element can be designed with multiple segments, in particular with two segments, so that a distal component, analogous to a natural finger or thumb, is pivotably mounted on a proximal component.When used with a thumb, the first pivot axis enables, in particular, abduction and adduction and thus rotation of the finger element about a pivot axis that is essentially oriented in the longitudinal extent of the prosthetic hand and extends from a wrist towards the fingertips. When used for a finger, the first pivot axis preferably extends perpendicular to the longitudinal extent of the finger element, i.e., perpendicular to the proximal-distal orientation. The finger element is coupled to a carrier and can be mounted directly on the carrier, for example, pivotably mounted thereon, or coupled to the carrier via a gear or a coupling element, such that the pivotable mounting is realized via a bearing point, for example, on the chassis.The carrier itself is coupled to a drive element; in particular, the drive element is mounted and fastened to the carrier, wherein the drive element can be coupled to the drive and is coupled when the prosthetic hand is assembled. The drive, in particular an electric motor drive, engages with the drive element and drives it, wherein the drive element is in turn coupled to the carrier in such a way that the force or torque is transmitted from the drive to the carrier. The coupling is effected via a coupling element, which in turn is coupled to the carrier in a torque-transmitting manner, in particular directly in a form-fitting manner or is connected or coupled to the carrier via one or more intermediate elements. The coupling element is mounted on the carrier so as to be axially displaceable along the longitudinal extent of the carrier and is elastically preloaded in the direction of the drive element.This makes it possible for the wearer and thus the entire prosthetic finger to be adjusted not only actively by the drive but also passively by a user or during use by externally acting forces. In particular, abduction and adduction with appropriate orientation and pivoting around the first pivot axis are then possible both actively and passively. Due to the elastic preload in the direction of the drive element, the coupling element does not influence the active adjustment by the drive, so that no energy, in particular no stored electrical energy, is consumed during passive adjustment. At the same time, during active adjustment by the motor drive, no holding force or restoring force due to an elastic element needs to be overcome, so that the active operation of the prosthetic finger can be optimized in terms of energy consumption.

[0015] InIn one embodiment, the drive element is designed as a gear or gear segment and has locking elements and / or friction areas on the front side, i.e. not on the circumference of the gear or gear segment. The coupling element also has locking elements and / or friction areas and is designed as a locking disc, wherein the locking elements and / or friction areas correspond to the front-side locking elements and / or friction areas of the drive element. By designing the drive element and the coupling element as locking discs, defined locking positions of the drive element relative to the coupling element and thus also defined positions of the prosthetic finger relative to the chassis are possible. Positioning via locking elements does not influence the active drive train with the motor drive as long as an adjustable resistance moment is not exceeded.The section modulus results from the elastic preload of the coupling element toward the drive element, as well as the geometric design of the locking elements and the friction properties of the friction areas. Due to the locking mechanism and the preferably evenly spaced arrangement of locking elements in the circumferential direction, the user can quickly and passively pivot the prosthetic finger, especially the thumb, or swing it sideways, for example, to place the prosthetic hand flat on a table.

[0016] InIn one embodiment, the locking elements on the drive element and the corresponding locking elements on the coupling element are designed as face gears with helical tooth flanks. The design of the tooth flanks in the form of helical surfaces enables surface contact throughout the entire locking process. This allows the maximum surface pressures in the contact area between the tooth flanks to be reduced, allowing the overall structural design to be significantly reduced while maintaining the same strength or transmittable torque.

[0017] To facilitate passive adjustment, the locking elements are inclined or beveled in at least one circumferential direction; preferably, the locking elements are beveled or beveled in both circumferential directions. The bevels or slopes can be straight or curved, so that teeth or waves are formed on the respective end faces of the drive element and the coupling element.

[0018] The drive element and the coupling element are preferably provided with crown gearing and are rotationally symmetrical, at least in some areas. The carrier has, for example, a pin on which the coupling element is mounted in a form-fitting and torque-transmitting manner. For this purpose, a gearing or other form-fitting device is arranged or formed on the outer side of the carrier, which ensures axial displacement of the coupling element and simultaneously allows torque to be transmitted, allowing the carrier to pivot about the first pivot axis.

[0019] The carrier is pivotally mounted about the first pivot axis, with the finger element being rotationally fixedly coupled to the carrier with respect to the axis. Thus, rotation of the carrier about the axis leads to rotation of the spring element about either this axis or about the pivot axis of the finger element.

[0020] In one embodiment, the finger element is pivotably mounted on the support, which is particularly advantageous when the support itself is pivotable relative to the chassis. This allows the finger elements or prosthetic fingers to be positioned more effectively and in a more diverse manner, enabling different types of grip and better grasping of objects.

[0021] In one embodiment, the finger element is pivotally mounted on the support about the first pivot axis, thereby enabling passive movement about the first pivot axis via the elastically preloaded coupling element. The pivoting about the second pivot axis can also be provided with a passive pivoting option.

[0022] In one embodiment, the finger element is coupled to the carrier via a gear or gear segment, thus simultaneously forming a gear ratio. The drive element, which acts on the carrier, is a component of the gear. A torque or a rotational movement is transmitted via a gear that is arranged on the carrier or

[0023] is formed, to a gear segment or a complete gear which is arranged, formed or fastened to the finger element. Further gear stages or gear stages can also be arranged or formed between the carrier and the finger element in order to transmit a corresponding rotary movement of the carrier to the finger element.

[0024] The elastic preload of the coupling element in the direction of the drive element is achieved in one embodiment via a spring, an elastomer element and / or a disc spring or a disc spring combination.

[0025] In In one embodiment, the finger element is mounted on a holder so as to be pivotable about a second pivot axis, the holder being fastened to the carrier. The holder, and thus also the finger element, pivots together with the carrier when the carrier is pivoted about the first axis. The finger element can be displaced about the second pivot axis independently of pivoting about the first axis, either passively or, in one embodiment, actively. For this purpose, a drive is provided which is mounted in or on the finger element and via which the finger element is mounted on the holder so as to be pivotable about the second pivot axis by a motor.

[0026] The first pivot axis and the second pivot axis are not parallel or collinear to each other, but rather intersecting. The pivot axes do not necessarily intersect. The pivot axes can also be skewed to each other and not intersect.

[0027] In one embodiment, the drive element is mounted on the carrier so as to be freely rotatable and only causes the coupling element to rotate and thus a force transmission to the carrier when the coupling element bears against the drive element with a sufficient contact force and transmits torques in a form-fitting and / or frictional manner.

[0028] The coupling element is loaded toward the drive element with a preload force sufficient to transmit a torque to the carrier. However, the torque is only transmitted up to a certain, predetermined, and advantageously adjustable load limit. If the resistance to displacement becomes too great or the applied torque becomes too large, the carrier decouples from the coupling element by being axially displaced relative to the carrier. This provides both overload protection and passive adjustability.

[0029] In one embodiment, a position sensor or a marker is assigned to the wearer, which detects the position of the wearer relative to the chassis. The information about the position of the wearer and thus also of the prosthetic finger relative to the chassis is important in order to know the starting position of the prosthetic finger the next time the user issues an adjustment command via myoelectric signals, so that the necessary adjustment path can be calculated. If, for example, the prosthetic finger is adjusted passively and is in a locked position, the finger will not be in the correct position when a closing command is given and cannot be moved into the desired or required position via the drive. The position sensor prevents incorrect operation.If the user generates a specific closing signal through a combination of muscle contractions, with which the prosthetic hand is to be brought into a specific end position, for example, a lateral grip, the control system calculates the necessary adjustment path for each prosthetic finger based on the available position signals. This ensures that, regardless of the current position of the prosthetic finger relative to the chassis, the correct end position is reached with every command.

[0030] The drive is designed in particular as an electric motor, which in turn drives an output element, for example a gear or a worm, which in turn engages with the drive element in an assembled state of the prosthetic hand.

[0031] The drive can be coupled to the output element via a gear and / or a clutch. The drive train from the motor drive, which is mounted in particular in the chassis, to the coupling element is advantageously designed to be self-locking, so that when the prosthetic finger and / or the wearer are subjected to stress, no forces are transmitted to the drive. The self-locking mechanism also ensures that no energy is required to maintain the position once assumed.

[0032] In addition to the possibility of making a simple and quick adjustment to different locking positions without the use of electrical energy, the described design also enables overload protection for the motor in the event of an unforeseen blockage of the adjustment of the finger element due to an obstacle or the like.

[0033] An exemplary embodiment of the invention is explained in more detail below with reference to the figures. Reference numerals denote identical components. They show: Figure 1 - a perspective view of a prosthetic hand; Figure 2 - a detailed schematic representation of the drive; Figure 3 - a detailed view from a different perspective; Figure 4 - an exploded view of part of the prosthetic finger; Figure 5 - a sectional view through an arrangement available Figure 3 ; Figure 6 - a cross-sectional view of a prosthetic finger Figure 7 - an exploded view of a variant; Figure 8 - a detailed section of the Figure 7 ; Figure 9 - a perspective detailed view of the Figure 7 ; Figure 10 - a sectional view of a detail of the Figure 8 ; as well as Figure 11 - an exploded view of components that Figure 10 .

[0034] In the Figure 11 shows a prosthetic hand 1 with a chassis 100 and a prosthetic finger 101. The prosthetic finger 101 is designed as a prosthetic thumb. Four additional prosthetic fingers are articulated and driven to the chassis 100. The prosthetic fingers have a base joint that articulates a proximal finger component to the chassis. A distal finger component is articulated to the proximal finger component and can be moved either individually or in combination with the proximal finger component. Via unspecified drives within the chassis, each finger can be moved individually or all fingers can be moved together in order to perform flexion toward the palm of the hand or extension into the extended position shown. The prosthetic finger 101, as a prosthetic thumb, can be pivoted about two axes 2, 4 and moved relative to the chassis.A first axis 2, which will be explained in more detail later, enables abduction and adduction; the second axis 4 enables flexion toward the palm of the hand or the other prosthetic fingers. The prosthetic thumb also has a two-jointed finger element 3 with a proximal

[0035] Finger component and a distal finger component. The distal finger component is pivotally mounted on the proximal finger component, similar to the other prosthetic fingers described. A drive, which will be explained in more detail later, is mounted within the chassis 100 and is designed as an electric motor. An energy storage device and a control device are either arranged within the prosthetic hand 1 or located in proximal prosthetic components, for example, a forearm shaft.

[0036] In the Figure 2the finger element 3 is partially shown, namely the proximal finger component, which is pivotally mounted about the first pivot axis 2. Pivoting about the first pivot axis 2 takes place via a holder 24, on which the finger element 3 is pivotally mounted about the second pivot axis 4. The two pivot axes 2, 4 are at an angle to one another, but do not intersect. In principle, it is also possible for both axes 2, 4 to intersect. The rotation about the first axis 2 takes place via a drive 5, which is designed as an electric motor and drives an output element 12 via a gear 10 in the form of a planetary gear and a clutch 11. The output element 12 is designed as a worm gear that rotates about a rotational axis 7. Thrust washers and bearing parts are arranged on both sides of the output element 12 in order to mount the output element 12 in the chassis 100.The output element 12 engages with its teeth in a worm gear serving as the drive element 17 and rotates it in one direction or the other about the pivot axis 2, depending on the direction of rotation of the electric motor 5. The drive element 17 is in turn reversibly connected to a coupling element 18 in a form-fitting manner, which will be explained in more detail later. For this purpose, spring elements 21 are arranged above the coupling element and are supported on a projection of a carrier 19. The carrier 19, in turn, is torsionally rigidly coupled to the holder 24 and pivots the finger element 3 when the carrier 19 is rotated about the first pivot axis 2.

[0037] In the Figure 3 is a free-cut structure of the components of the Figure 2shown in a different perspective. If the worm 2 is driven, the drive element 17 rotates about the pivot axis 2. The drive element 17 is supported at the bottom on a clamping element 20; below the clamping element 20 there is a magnetic ring 22 which serves as a signal generator for a position sensor (not shown) in the chassis 100. The drive element 17 has locking elements 171 or form-locking elements on the upper end face, which are arranged on the end face in a manner distributed over the circumference. The distribution is advantageously even over the circumference. Above the drive element 17, the coupling element 18 is in form-locking connection with the locking elements 171, since the underside of the coupling element 18 is designed to correspond to the top side of the drive element 17.

[0038] The coupling element 18 is mounted on the support 19 for axial displacement along the longitudinal extent of the first pivot axis 2. Displacement is prevented by the spring element 21 in the form of a disc spring assembly. Internal teeth are formed on the inside of the coupling element 18, which correspond to external teeth on the support 19. The internal teeth of the coupling element 18 engage with the external teeth of the support 19 and, upon rotation of the drive element 17, cause the support 19 to be displaced about the first pivot axis 2. The support 19 is mounted in a torque-transmitting or torsionally rigid manner in the holder 24, which in turn has two bearing elements 23, 25, with which the holder 24 is mounted in the chassis 100. The second pivot axis 4 is formed on the holder 24, around which the finger element 3 can be pivoted palmarly for gripping.

[0039] The Figure 3 and better the Figure 4It can be seen that the locking elements 171 on the drive element 17 are designed with starting ramps or slopes in both circumferential directions, and the corresponding locking elements 181 of the coupling element 18 also have starting ramps or slopes. When the motor drive 5 is activated, the output element 12 rotates about the axis of rotation 7 and drives the drive element 17. The drive element 17, which is otherwise freely rotatable on the carrier 19, is connected to the locking elements 171 and 181.

[0040] Torque-transmitting connected to the coupling element 18. The coupling element 18, as a locking disk, is torsionally rigidly coupled to the carrier 19 via a toothing 191, so that rotation of the drive element 17 leads to rotation of the carrier 19. Due to the torsionally rigid mounting of the holder 24 on the carrier 19, the finger element 3, together with the holder 24, is also pivoted about the first pivot axis 2. As soon as resistance to pivoting about the first pivot axis 2 occurs, for example because an end position is reached or the prosthetic finger 101 is pressed against an object, a relative movement can occur between the drive element 17 and the coupling element 18. Due to the oblique design of the locking elements 171, 181, rotation with simultaneous axial displacement of the coupling element 18 upwards along the longitudinal extent of the first pivot axis 2 is possible.This occurs against the preload force applied by the spring elements 21. If the applied torque is too great to be transmitted to the carrier 19 by the positive and frictional connection between the drive element 17 and the coupling element 18, the coupling element 18 is raised until its underside rests on the upper side of the locking element 171 of the drive element 17 and slips through. In this way, for example, an overload protection device is provided.

[0041] To effect passive adjustment of the finger element 3 or the prosthetic finger about the first pivot axis 2, a torque is applied about the first pivot axis 2 via the holder 24 or the finger element 3. The drive train from the motor drive 5 via the output element 12 to the drive element 17 is self-locking, so that when torque is applied, the drive element 17 does not drive the output element 12. The holder 24 with the carrier 19 then rotates relative to the drive element 17. Due to the positive and torsionally rigid coupling between the carrier 19 and the coupling element 18, this leads to an axial displacement of the coupling element 18 upwards against the preload of the spring elements 21 until a next locking position is reached.

[0042] The spring elements 21 ensure the force-locking and form-locking connection of the drive element 17 and the coupling element 18 up to a limiting torque. Above the limiting torque, the coupling element 18 or the locking disc moves axially on the carrier 19 along the longitudinal extension of the first pivot axis 2 until the maximum height of the locking elements 171 is reached. If the torque continues to be applied, the coupling element 18 moves together with the carrier 19 and the holder 24 attached thereto, as well as the prosthetic finger 101, to the next locking position.

[0043] In the Figure 4It can be seen that a total of six locking elements 171 or notches are arranged or formed on the upper end face of the drive element 17. Thus, the carrier 19 with the holder 24 and the prosthetic finger can be moved into six locking positions, since there are also six recesses on the underside of the coupling element 18. With a different pitch or with a larger or smaller number of locking elements 171, 181 or notches, different numbers of locking positions are possible. Figure 4 It can be seen that the coupling element 18 has an internal toothing that corresponds to an external toothing 191 of the carrier 19. The spring elements 21 are supported on the upper side of the coupling element 18 on the one hand and on a shoulder 192 of the external toothing 191 on the other hand on the carrier 19 and, in the assembled state, cause a preload of the coupling element 18 in the direction of the drive element 17.

[0044] In the Figure 5 is a sectional view of the assembled state according to Figure 3 The clamping element 20 has an external thread that is screwed into an internal thread within the carrier 19. The clamping element 20 provides an axial support for the drive element 17, which can rotate freely around the outer circumference of the carrier 19. InA magnetic ring 22 is arranged on the outer circumference of the clamping element 20. This magnetic ring serves as a marker or positioning aid to determine the orientation of the magnetic field and thus the actual position of the prosthetic finger 101 relative to the chassis 100. The coupling element 18 above the drive element 17 is preloaded relative to the drive element 17 via the two disc springs of the spring element 21, which bear against the shoulder 192 of the external toothing 191. The holder 24 is clamped or screwed on, or otherwise non-rotatably mounted on the carrier 19 above the toothing 191.

[0045] The Figure 6showed a section through the prosthetic finger 101 with a drive 6 arranged within the finger element 3 for actuating and pivoting the finger element 3 about the second pivot axis 4, so that opening and closing of the thumb can take place independently of abduction or adduction of the thumb about the first pivot axis 2.

[0046] In the Figure 7 A variant is shown in which the finger element 3 is pivotally mounted on the chassis 100 about a first pivot axis 2. Within the chassis 100, a motor drive 5 is mounted and provided with an output element 12 via a gear 10. The output element 12 is a gear on a shaft that engages with the drive element 17. The basic structure of the drive element 17 with the coupling element 18, which is not visible in this illustration, with the carrier 19 and the spring element 21 corresponds to the structure of the embodiment according to the Figures 2 to 6A gear 26 is mounted on the support 19 in a rotationally fixed manner and engages a gear segment 36 that is arranged, formed, or attached to the finger element 30. Upon rotation of the gear 26, the finger element 3 is moved in one direction or the other via the gear segment 36 about the first pivot axis 2 on the chassis 100.

[0047] In the Figure 8In a sectional view from a different perspective, the chassis 100 is shown with the motor drive 5 arranged therein and the gear 10, via which the output element 12 is driven. The output element 12, as a gear, engages with the drive element 17, which is rotatably mounted on the carrier 19. The coupling element 18 with end-face locking elements (not shown) is pressed against the drive element 17 by the spring element 21. The spring element 21 consists of several disc springs or disc spring assemblies and loads the coupling element 18 in the longitudinal extent or in the axial direction towards the drive element 17. The coupling element 18 is mounted on the carrier 19 in a torsionally rigid and axially displaceable manner; the specific structure will be explained later. The spring element 21 is supported on the opposite side on the gear 26, which is also mounted on the carrier 19 in a rotationally fixed manner and is axially secured by a nut 27.The spring preload of the spring element 21 can be adjusted via the nut 27. The gear 26 meshes with the gear segment 36, which in turn is coupled to the finger element 3 in a torque-transmitting or torsionally rigid manner, so that a rotation of the gear 26 leads to a pivoting of the finger element 3 about the pivot axis 2.

[0048] In the Figure 9 A perspective detailed view of the finger element 3 on the chassis 100 is shown. The finger element 3 is mounted on the chassis 100 about the first pivot axis 2. The motor and the transmission are also mounted within the chassis 100. Also visible is the drive element 17, which is coupled via the carrier 19 to the gear 26 via the coupling element (not shown), which is pressed against the drive element 17 by the spring element 21. This gear, in turn, drives the finger element 3.

[0049] In the Figure 10A sectional view of the component structure with the carrier 19 is shown. The drive element 17 is rotatably mounted on the carrier 19. The coupling element 18 is provided with spur gear teeth and is mounted on the carrier 19 for axial movement and torque transmission. The torsionally rigid or torque-transmitting mounting is achieved via pins 28, which are arranged in corresponding recesses in the carrier 19 and the bore of the coupling element 18. The spring elements or the spring element 21 press the coupling element 18 in the longitudinal extension of the pins 28 onto the drive element 17, which is supported on a shoulder on the carrier 19.

[0050] On the other side of the spring element 21, the gear 26 is also axially movable and torsionally fixed by pins 29. Axial locking is provided by the nut 27. The pins 29 are formed in recesses on the outside of the carrier 19 and the inside of the gear 26, respectively.

[0051] In the Figure 11 are the individual components of the Figure 10shown in an exploded view. The drive element 17 is freely rotatably mounted on a lower shoulder on the carrier 19. On the side opposite the shoulder 195, which is opposite the coupling element 18, recesses or projections in the form of locking elements 171 are formed, into which corresponding recesses 181 or projections on the end face of the coupling element 18 engage. The coupling element 18 has recesses 183 on the inside of a flange 182, into which the pins 28 engage. Corresponding recesses 193 are formed on the outside of the carrier 19, in this case four recesses 193, so that an axially displaceable, rotationally fixed mounting of the coupling element 18 on the carrier 19 results, corresponding to the toothing in the other exemplary embodiment.The disc springs of the spring element 21 rest on the back of the locking elements 181 and are supported on the opposite side by the gear 26, which is secured axially to a thread via the nut 27. Corresponding to the pins 28 for the coupling element 18, the gear 26 is secured in a rotationally rigid and axially displaceable manner via six pins 29, in recesses 194 on the carrier 19 and on the inside of the gear 26. The gear 26 engages a gear segment or another gear to drive the finger element 3.

Claims

1. A prosthetic finger with a motor drive (5) via which the prosthetic finger (101) is pivotable relative to a chassis (100) about a first pivot axis (2), with a finger element (3) which is mounted on the chassis (100) pivotably about the first pivot axis (2) and with a carrier (19) which is coupled to the finger element (3), on said carrier (19) a drive element (17) is mounted which can be coupled to the motor drive (5) and is coupled to the carrier (19) in a torque-transmitting manner, characterized in that the drive element (17) is coupled to the carrier (19) in a torque-transmitting manner via a coupling element (18), wherein the coupling element (18) is mounted on the carrier (19) to be axially displaceable and elastically pretensioned in the direction of the drive element (17).

2. The prosthetic finger as claimed in claim 1, characterized in that the drive element (17) is designed as a toothed wheel or toothed wheel segment and has latching elements (171) and / or friction regions at a front end, and the coupling element (18) is designed as a latching disk with correspondingly designed latching elements (181) and / or friction regions.

3. The prosthetic finger as claimed in claim 2, characterized in that the latching elements (171, 181) are inclined or beveled in at least one circumferential direction.

4. The prosthetic finger as claimed in claim 2 or 3, characterized in that the latching elements (171) on the drive element (17) and the correspondingly designed latching elements (181) on the coupling element (18) are configured as a crown gear with helical tooth flanks.

5. The prosthetic finger as claimed in any one of the preceding claims, characterized in that the coupling element (18) is mounted on the carrier (19) with a form fit.

6. The prosthetic finger as claimed in any one of the preceding claims, characterized in that the carrier (19) is mounted pivotably about the first pivot axis (2), and the finger element (3) is coupled to the carrier (19) for conjoint rotation.

7. The prosthetic finger as claimed in any one of claims 1 to 5, characterized in that the finger element (3) is mounted pivotably on the carrier (19).

8. The prosthetic finger as claimed in claim 7, characterized in that the finger element (3) is mounted pivotably about the first pivot axis (2).

9. The prosthetic finger as claimed in claim 7 or 8, characterized in that the finger element (3) is coupled to the carrier (19) via a toothed wheel or toothed wheel segment.

10. The prosthetic finger as claimed in any one of the preceding claims, characterized in that the finger element (3) is mounted on a holder (24) pivotably about a second pivot axis (4), and the holder (24) is secured on the carrier (19).

11. The prosthetic finger as claimed in claim 10, characterized in that the finger element (3) has a drive (6) and is mounted on the holder (24) pivotably by motor.

12. The prosthetic finger as claimed in either of claims 10 and 11, characterized in that the pivot axes (2, 4) are oriented crosswise.

13. The prosthetic finger as claimed in any one of the preceding claims, characterized in that the drive element (17) is mounted freely rotatably on the carrier (19).

14. The prosthetic finger as claimed in any one of the preceding claims, characterized in that the coupling element (18) is loaded in the direction of the drive element (17) with a pretensioning force that permits a decoupling of the coupling element at a predefined torque.

15. The prosthetic finger as claimed in any one of the preceding claims, characterized in that the carrier (19) is assigned a position sensor or marker via which the position of the carrier (19) relative to the chassis (100) is detected.

16. A prosthetic hand having a chassis (100) and a prosthetic finger (101) as claimed in any one of the preceding claims.

17. The prosthetic hand as claimed in claim 16, characterized in that the motor drive (5) is designed as an electric motor, which drives an output element (12) that engages with the drive element (17).

18. The prosthetic hand as claimed in claim 17, characterized in that the motor drive (5) is coupled to the drive element (17) via a gearing (10) and / or a coupling (11).