End effector for a surgical instrument and surgical instrument with an end effector

Abstract

End effector (7) for a surgical instrument (1), comprising: - a drive unit (6) with an electric motor (12) which rotates a shaft (14, 18), - a rotation-translation gear (29) connected to the shaft (14, 18), which converts a rotational motion of the shaft (14, 18) into a translational motion; and - several working elements (8) of the end effector (7) which are coupled to the rotation-translation gear (29) and are translationally driven by it, wherein the rotation-translation gear (29) comprises several planar cams (36a, 36b) which each engage with and guide at least one translationally driven working element (8, 8a, 8b), wherein the rotation-translation gear (29) comprises several rotatable elements (26a, 26b) with a corresponding planar curve (36a, 36b) which can be actuated independently of each other, characterized by the fact that the rotation-translation gear (29) includes a clutch (42) that switches between the two rotatable elements (26a, 26b).

Description

[0001] The invention relates to an end effector for a surgical instrument and to a surgical instrument with an end effector.

[0002] Surgical procedures on the human body are increasingly performed using minimally invasive techniques with the assistance of surgical robots. Depending on the type of procedure, the surgical robots can be equipped with various surgical instruments, such as endoscopes, cutting, grasping, or suturing instruments. During an operation, the instruments are inserted into the patient's body via a sheath using one or more robots. During the operation, the surgical instrument is then controlled by a surgeon using an input device on the robot system, such as joysticks or gesture control.

[0003] A wide variety of instruments are used in surgery today, such as endoscopes, laparoscopic instruments, cutting, grasping, holding, joining, or suturing instruments, as well as other surgical tools. The actual end effector, such as a scalpel, scissors, needle, scraper, file, grasper, etc., is located at the distal end of the surgical instruments or tools. Surgical instruments known from the prior art are usually operated by means of a cable drive.

[0004] Fig. Figure 1 shows the distal end of a surgical instrument 1 known from US Patent 6,312,435 B1, designed for robot-assisted minimally invasive surgery. The instrument 1 comprises a shaft 3 extending in a longitudinal direction L, at the distal end of which the actual end effector 5, in this case a so-called Pott's scissors, is pivotably attached. The scissors comprise two blades that can be moved open and closed about the axis A1. The entire end effector 5 can also be pivoted about a pivot axis A2 extending transversely to the axis A1. The surgical instrument 1 can also be rotated about its longitudinal axis L. In this embodiment, the individual joints are each moved by means of a cable drive (not shown). However, the assembly and drive mechanism of such a surgical instrument are relatively complex and elaborate.

[0005] From WO 2011 / 034 081 A1, a remotely controlled actuator for medical purposes is known. The actuator has a gripping mechanism that can be driven by a drive unit via a rotary shaft and a gear stage with a spiral cam.

[0006] WO 99 / 26 757 A2 discloses a clamping system which can be used on machine tools in general for clamping workpieces.

[0007] From DE 10 2006 031 294 A1 a device for guiding and holding medical and / or surgical instruments, devices and the like is known.

[0008] US patent 4 955 653 A describes an end effector for robots that uses a rotatable plate with a spiral guide.

[0009] From JP 5 048 004 B2, an electric gripper is known in which a large number of gripping elements can be opened and closed relative to each other, using a stepper motor as a drive source.

[0010] Finally, further grippers and / or surgical devices are known from documents US 6 505 871 B2, FR 2 564 358 A1, US 2014 / 0 005 708 A1 and US 2012 / 0 310 252 A1.

[0011] In light of the prior art, the object of the present invention is to improve an end effector in such a way as to provide the greatest possible flexibility in its operation. Furthermore, it is an object of the present invention to create an end effector with an integrated drive unit.

[0012] This problem is solved according to the invention by the features specified in the independent claims. Further embodiments of the invention are set forth in the dependent claims.

[0013] According to the invention, an end effector for a surgical instrument is proposed, comprising a drive unit with an electric motor that rotates a shaft. The drive unit further includes a rotary-translational transmission that converts the rotational movement of the shaft into a translational movement and engages a working element, such as a gripper, so that it is driven translationally, preferably purely translationally, by the transmission. Such an end effector is thus significantly simpler in design than an end effector with a cable drive.

[0014] The translational movement of the driven working element preferably runs transversely to an axis of rotation around which the shaft of the drive unit rotates.

[0015] A working element can be, for example, the jaw of a gripper, a scalpel, a scissor blade, a needle, a clamp, or any other element of a known medical instrument. An end effector can also contain working elements of different types; for example, the end effector can be designed as an anvil scissors, in which one working element is the cutting element and the other is the anvil complementary to the cutting element.

[0016] Furthermore, sensors can be attached to and / or integrated into the working elements. These sensors typically measure pressure, force, torque, temperature, acceleration / speed, and displacement. Imaging sensors are also conceivable, such as those already available in miniature versions in so-called image processors. These sensors then serve not only to provide informational support to the surgeon but also to control the surgical instrument and / or robot system. The integration of multiple sensors (keyword: sensor fusion) allows the surgeon or the surgical robot system to make decisions that support their work and / or, above all, serve for critical assessments and analyses of functional safety.The task of such sensors would also be to detect errors in the system or incorrect operation, electrical, software-related and / or mechanical failures and / or external influences such as collisions, and / or to evaluate, weigh, and initiate appropriate actions according to a safety plan.

[0017] Another application for these sensors would be enabling a localization and detection system for the gripper and / or instrument. Specifically, the spatial and temporal sensory acquisition in Cartesian space not only allows for collision detection and avoidance, but also for computer-aided and / or model-based collision analysis. The ability to predict collisions allows for very early warnings and, consequently, a collision avoidance strategy. This would mean that the surgeon would not only have an assistance function at their disposal, but also the possibility of an automatic emergency stop. Thus, collisions that would otherwise be unavoidable for the surgeon could be prevented in advance.Assistance as well as automatic emergency and help functions can therefore be installed / implemented not only locally, i.e. in the end effector itself, but also in the instrument and / or in the robot system.

[0018] The end effector according to the invention preferably comprises means for detachably attaching the end effector to the shaft of a surgical instrument. The end effector can thus be easily replaced or serviced. For attaching the end effector to a surgical instrument, for example, a screw or plug connection can be provided, which may optionally include locking elements. Alternatively, the end effector can also be permanently mounted to the surgical instrument.

[0019] According to a preferred embodiment of the invention, the rotary-translational transmission comprises a rotatable element with a planar cam that engages with and guides at least one translationally driven working element. The rotating element is preferably provided at one end of the electrically driven shaft and can, for example, be disk-shaped.

[0020] The curve provided on the rotating element can, for example, be designed as a spiral thread or as a spiral groove.

[0021] The curve preferably spans a flat surface whose surface normal points in the direction of the rotation axis of the electrically driven shaft.

[0022] According to a particular embodiment of the invention, the rotary-translational transmission can also comprise several cams, each of which engages with at least one working element and drives it differently. For example, several working elements can be driven with different gear ratios. Alternatively or additionally, several working elements could also be driven sequentially, i.e., independently of one another.

[0023] One embodiment of an end effector according to the invention comprises at least one first working element that engages with a first cam of the rotary-translational drive, and at least one second working element that engages with a second cam. The at least one first working element can thus be driven by a first motion profile, and the at least second working element by a second motion profile, which may be different. Such an embodiment of an end effector can, for example, comprise two first working elements guided by a first cam and a second working element guided by a second cam.

[0024] According to a particular embodiment of the invention, the end effector comprises two working elements which are arranged opposite each other with respect to the axis of rotation of the shaft and which can be moved towards or away from each other by a rotational movement of the shaft. Both working elements preferably engage with the same cam.

[0025] The rotating element of the rotary-translation gearbox is preferably designed as a separate component that can engage with the shaft of the drive unit. For example, a pinion can be provided at the end of the shaft, which can engage in a corresponding recess on the rotating element.

[0026] Preferably, the rotating element of the rotary-translation gearbox is pre-tensioned so that the working elements can close automatically, for example, in the event of a drive unit failure. For instance, a restoring component, such as a (spiral) spring, can be attached to the rotating element and supported against the inner wall of the end effector housing. A rotational movement of the rotating element in the opening direction of the end effector tensions the spring, thus counteracting the drive unit. The spring can also be integrated into the end effector already pre-tensioned, so that a force is exerted by the spring in the closing direction even when the end effector is closed. When the spring relaxes, it drives the rotating element in the closing direction of the end effector. The spring force is advantageously selected to overcome frictional losses and opposing torques from the motor.

[0027] Preferably, the actual tool of the end effector is also designed as a separate component that can be detachably attached to the drive unit of the end effector. In this case, the tool of the end effector preferably includes a fastening device, such as a screw, plug, or snap-fit ​​connection. However, the drive unit and the end effector could also be designed as a single unit.

[0028] According to a preferred embodiment, the entire end effector, including its drive unit, can be mounted on the shaft of a surgical instrument. For this purpose, a suitable connection, e.g., a screw, plug, or snap-fit ​​connection, or any other known quick-connect mechanism, such as a bayonet fitting, can be provided.

[0029] The end effector according to the invention can also include a second drive unit with which the end effector can be rotated about the axis of rotation of the shaft. This further improves the operating possibilities of the surgical instrument.

[0030] A particularly simple design of an end effector results when the first drive unit for actuating the tool or working element of the end effector is constructed identically to the second drive unit for rotating the end effector.

[0031] The drive units according to the invention preferably each comprise an electric motor. The drive unit can further comprise a gearbox with which the rotary motion of the shaft driven by the electric motor is transmitted to a second shaft.

[0032] The invention also relates to a surgical instrument for use on a surgical robot for minimally invasive surgery. The surgical instrument has a shaft extending longitudinally along the instrument, with an end effector, as described above, provided at the distal end of the shaft.

[0033] The surgical instrument according to the invention can further comprise a manipulator for positioning the end effector, which includes several rotatable elements. The manipulator can, for example, include at least one first rotatable element rotatably arranged about a first axis of rotation, and at least one second rotatable element rotatably arranged about a second axis of rotation. Furthermore, the manipulator includes a first drive unit for driving the first rotatable element and a second drive unit for driving the second rotatable element. The drive units are integrated into the manipulator. The first and second axes of rotation are also arranged at an angle to each other. This angled arrangement of the axes of rotation makes it possible to drive each rotatable element directly by means of an electric motor, without having to redirect the rotational movement of the electric motor to the pivot axes via a cable mechanism.

[0034] In an advantageous embodiment of the invention, the drive units of the manipulator and the drive unit of the end effector are identically constructed. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The invention is explained in more detail below with reference to the accompanying drawings. These show: Fig. 1 a surgical instrument known from the prior art; Fig. 2a a schematic side view of the tool of an end effector with two working elements; Fig. 2b a schematic top view of the end effector of Fig. 2a, which has a rotatable element of a rotation-translation gear with a single drive cam; Fig. 3a a schematic side view of an end effector with three working elements; Fig. 3b a schematic top view of the end effector of Fig. 3a, which has two drive curves of a rotation-translation gear with two rotatable elements; Fig. 4. A view of the tool of an end effector with mechanical and electrosurgical working elements; Fig. 5 a perspective view of a surgical instrument with an end effector and an integrated manipulator for positioning the end effector; Fig. 6 a perspective view of an end effector with three work elements; Fig. 7 a sectional view of the end effector of Fig. 6; Fig. 8 a perspective view of an end effector with four work elements; Fig. 9 a perspective view of an end effector designed as a gripper in an open gripper state; Fig. 10 the end effector of Fig. 9 in a closed state of the gripper; Fig. 11 another embodiment of an end effector with an additional drive unit for rotating the end effector about its longitudinal axis; and Fig. 12 a sectional view of the distal end of a surgical instrument with an end effector and a manipulator for positioning the end effector.

[0036] Regarding the explanation of Fig. 1 refers to the introductory description.

[0037] Fig. Figure 2a shows a schematic side view of tool 38 of an end effector 7, as exemplified in Fig. Figure 9 illustrates this. In this case, the end effector 7 is designed as a gripper with two opposing working elements 8. The two working elements 8 are guided within a guide groove 9 at a proximal section. At their proximal end (shown below in the image), the working elements 8 engage with a rotatable element 26, which is part of a rotary-translational transmission 29. When the element 26 is driven to rotate, the working elements 8 move towards or away from each other in the direction of arrows B. A rotational movement of the element 26 is thus converted into a purely translational movement of the working elements 8. This translational movement occurs transversely to the rotational axis 10 of the element 26 in a radial direction.

[0038] Fig. Figure 2b shows a schematic top view of the rotatable element 26. As can be seen, the rotatable element 26 encompasses a curve on its distal surface that engages with the working elements 8. The curve 36 is designed here as a helical thread, but could, for example, also be designed as a groove. The curve 36 spans a planar surface whose surface normal points in the direction of the axis of rotation 10 (in Fig. Figure 7 shows the axis around which element 26 rotates.

[0039] Fig. Figure 3a shows a schematic side view of the tool 38 of an end effector 7 with three working elements 8, as exemplified in Fig. Figure 6 shows that the working elements 8 are in turn engaged with a rotatable element 26 of a rotary-translational transmission 29, wherein the working elements 8a engage with a first rotatable element 26a and the working element 8b engages with a second rotatable working element 26b. The rotatable elements 26a and 26b are rotatable independently of each other and can, for example, be nested within one another. By rotating the elements 26a and 26b, the individual working elements 8a and 8b can thus be moved independently towards or away from each other in the direction of arrows B, depending on which rotatable element 26a and 26b is rotating. The rotatable elements 26a and 26b can be driven by the same drive unit 6 or by different drive units. In a preferred embodiment of the invention, as shown in Figure 6, the working elements 8a and 8b are rotatable independently of each other and can be arranged, for example, nested within each other. Fig. As shown in Figure 3a, the rotary-translational transmission 29 comprises a clutch 42, in particular a dual clutch, which is functionally integrated between the two rotating elements 26a and 26b and can switch between the two elements 26a and 26b. Thus, only one drive unit 6 is required to drive both rotating elements 26a and 26b from the same drive unit 6. Depending on the switching state of the dual clutch 42, both rotating elements 26a and 26b can then be actuated either simultaneously or alternately and separately from one another. That is, in the latter variant, either one rotating element 26a or the other rotating element 26b is actuated.

[0040] Fig. Figure 3b shows a schematic top view of the rotatable elements 26a and 26b according to Fig. 3a. Each of the rotatable elements 26a and 26b has a corresponding cam 36a and 36b. One of the cams, e.g., 36a, serves to drive two of the three working elements, namely the working elements 8a (e.g., the working element shown on the left and right). The second cam, e.g., 36b, engages only with one of the working elements, namely working element 8b (e.g., the middle one). The individually driven working element 8b can thus be driven independently of the other two working elements 8a. Such an embodiment of a gripper can, for example, be used to first roughly position an object and then fix it using the third working element 8a. Another application could, for example, consist of first gripping an object using two working elements 8b and then performing an electrosurgical operation by moving the third working element 8a against the object with a time delay.The third working element 8a in this case is designed as an electrosurgical element, preferably typically as mono- or bipolar RF tools for cutting and coagulating body tissue.

[0041] Fig. Figure 4 shows another embodiment of a tool 38 of an end effector, as exemplified in Fig. Figure 8 is shown. In this case, the end effector 7 comprises four working elements 8, arranged in pairs opposite each other. As mentioned above, the four working elements 8 can be driven by a common rotatable element 26. Alternatively, the working elements 8 can be driven in pairs. In this case, the end effector 7 has two rotatable elements 26a and 26b, with two opposing working elements 8a engaging with the first rotatable element 26a and the other two opposing working elements 8b engaging with the second rotatable element 26b. Thus, two of the working elements 8a, 8b are guided by a cam 36a or 36b, respectively. The direction of movement of the two pairs is exactly perpendicular to each other. In this embodiment, a first pair of working elements 8a is, for example, designed as a mechanical gripper. The pair of working elements 8b arranged perpendicular to it, on the other hand, can be, for example, a gripper.be designed as an electrosurgical tool capable of transmitting current and / or voltage.

[0042] Fig. Figure 5 shows a perspective view of a surgical instrument 1 for minimally invasive surgery, designed for attachment to a surgical robot. The surgical instrument 1 includes a mounting device 2 at its proximal end (shown on the right in the image), which allows it to be attached to a surgical robot or an instrument holder.

[0043] The in Fig. The surgical instrument 1 shown in Figure 2 further comprises a shaft 3 extending in a longitudinal direction L, at the distal end of which (shown on the left in the image) a manipulator 4 is arranged for positioning an end effector 7. The surgical instrument 1 can be, for example, a grasping, holding, cutting, sawing, grinding, joining, or joining instrument, or any other surgical instrument. The end effector 7 of the surgical instrument 1 can be, for example, a scalpel, scissors, forceps, trocar, etc. The use of optical or image-processing tools, such as lights, laparoscopes, or cameras, is also possible.

[0044] Fig. Figure 6 shows a perspective view of an end effector 7 according to a first embodiment of the invention. The end effector 7 comprises a drive unit 6, at the distal end of which (shown on the left in the image) the actual tool 38 is provided. The end effector 7 is designed here as a gripper with three working elements 8. Each working element 8 is guided in a groove 9 and can perform a translational movement in the radial direction when the end effector 7 is actuated. The three working elements 8 are arranged at an angle to each other, preferably at 120° angles.

[0045] The tool 38 of the end effector 7 is detachably attached to the drive unit 6. A fastening device 5 is provided at the proximal end of the tool 38 for securing it. The fastening device 5 can, for example, be a screw, plug, or snap-fit ​​connection. With the aid of the fastening device 5, it is possible to quickly and easily exchange the tool 38 for another or replace it as needed. It is therefore no longer necessary to replace the entire surgical instrument 1.

[0046] Alternatively, the tool 38 could of course be designed together with the drive unit 6 as a single unit. In this case, a corresponding fastening device could be provided at the proximal end of the drive unit 6.

[0047] Fig. Figure 7 shows a sectional view of the end effector 7 of Fig. 6. The end effector 7 essentially comprises two detachably connected units, namely a drive unit 6 and the tool 38 attached to the distal end of the drive unit 6. In this embodiment, the drive unit 6 comprises an electric motor 12, which rotates a shaft 14. The shaft 14 is rotatably mounted in a housing 11 of the drive unit 6 by means of two ball bearings 15, 16. The drive unit 6 further comprises a gearbox 17, which transmits the rotary motion of the shaft 14 to an output shaft 18. The output shaft 18 is also rotatably mounted in the housing 11 of the drive unit 6 by means of two ball bearings 19, 20.

[0048] At the free end of the output shaft 18 is a pinion 21, which is inserted into a corresponding recess of a rotary-translation gear 29. Alternatively, any other known device for torque transmission could of course be provided in which the torque exerted by the electrically driven shaft 18 is transmitted directly to the tool 38, such as a shaft-hub connection.

[0049] The in Fig. The rotary-translational transmission 7 shown comprises a rotatable element 26, which is non-rotatably connected to the shaft 18. This element is disk-shaped and has a planar curve 36 on its distally facing surface, which engages with the working elements 8 or gripping jaws of the tool 38. When the output shaft 18 rotates, driven by the electric motor 12, the rotatable element 26 also rotates about the axis of rotation 10. This rotational movement is then transmitted via the rotary-translational transmission 29 to the grippers 8, so that they move towards or away from each other purely translationally. The gripping jaws 8 are guided within grooves 9 that run essentially in a radial direction.

[0050] A plug connection is provided here for attaching the tool 38 to the distal end of the drive unit 6. For this purpose, the tool 38 comprises a mounting section 5 that can be plugged onto the distal end of the drive unit 6. The mounting section 5 preferably includes locking elements (not shown) for snapping into the drive unit 6.

[0051] The in Fig. The drive unit 6 shown in Figure 7 further comprises a brake 25 for decelerating a drive movement. A continuous channel 39 also runs within the drive unit 6, through which a medium, e.g., air or a liquid, such as a saline solution, can be guided. The channel 39 passes through the shafts 14, 18. The shafts 14, 18 are therefore hollow inside. The tool 38 has a through-opening corresponding to the channel 39, through which the medium can be guided to the surgical site. During an operation, the medium is preferably introduced into the channel 39 at a pressure p1 that is greater than the pressure p2 prevailing in the patient.

[0052] The in Fig. The end effector shown in Figure 7 also has a restoring component 41 that acts on the rotating element 26 and is supported on the inner wall of the mounting section 5. The restoring component 41 is designed as a coil spring and is tensioned when the rotating element 26 is actuated in the direction of rotation to open the working elements 8. The coil spring 41 can also be pre-tensioned so that it exerts a restoring force on the rotating element 26 even when the gripper is closed. This restoring force causes the working elements 8 to close in the direction of arrow B (see Figure 7). Fig. 2a and Fig. 3a) driven. Since the spring force of the spring 41 acts in the closing direction, it opposes the torque of the drive unit 6 when the end effector opens. When the end effector closes, however, the spring force acts together with the torque of the drive unit 6. The spring force is preferably selected such that the end effector 7 can close automatically if the drive unit 6 fails. Preferably, however, the spring is designed such that it closes the working elements 8 only to the extent that the working elements 8 no longer move as described in Fig. 8 or Fig. 11 shows, project radially beyond the fastening section 5, but at least be flush, as e.g. in Fig. Figure 9 shows that the working elements 8 are not fully closed by the restoring force of the spring. This prevents the end effector 7 from unintentionally grabbing an object due to its automatic closing movement in the event of a failure of the drive unit 6.

[0053] It should be noted at this point that the invention is not limited to the use of a spring, but alternatively other components can be used as the retracting component 41, which cause the working elements 8 to close automatically.

[0054] Fig. Figure 8 shows a perspective view of an end effector 7 with a tool 38 comprising four work elements 8. In this case, the work elements 8 are driven in pairs by different cams 36a, 36b. For example, the two horizontally shown work elements 8 can be engaged by a first cam 36a, and the two vertically shown work elements 8 by a second cam 36b. Depending on the design of the cams 36a, 36b, it is therefore possible to drive the two pairs of grippers at different speeds. In this embodiment, a coupling 42 is preferably installed, as shown in Fig. Figure 3a shows that curves 36a and 36b can be driven together or separately, depending on the clutch's switching state. The working elements 8 can be operated analogously to... Fig. 4. They can be equipped with different functions. Accordingly, a pair of working elements can be specifically designed for electrosurgical procedures.

[0055] Fig. Figure 9 shows a further embodiment of an end effector 7 designed as a gripper, the tool 38 of which has two opposing gripper elements 8 that are guided at their proximal end in a groove 9. By means of a rotating drive movement of the electric motor 12, the gripper elements 8 can again be moved towards or away from each other. Fig. 9 represents the open state, and in Fig. 10 shows the closed state.

[0056] Fig. Figure 11 shows another embodiment of an end effector 7 with two gripping elements 8. In contrast to the embodiment of Fig. 9 and Fig. However, in this case, the end effector 7 includes an additional drive unit 6d, which is arranged at the proximal end of the drive unit 6. The additional drive unit 6d serves in this case to rotate the tool 38 about the longitudinal axis 10 of the end effector 7. The additional drive unit 6d is preferably identical in design to the drive unit 6 and engages with its distal end in a recess 22 provided at the proximal end 24 of the drive unit 6 (see Figure 10). Fig. 7) The drive units can thus be coupled to each other via a shaft-hub connection, whereby the shaft 18 or the pinion 21 of one drive unit 6d can be connected to the hub 22 of the other drive unit 6, which is integrated into the housing 11. When the electric motor 12 of drive unit 6d is actuated, the torque is then transmitted to the drive unit 6 and the tool 38, which thus rotate together around the axis 10. The two drive units 6 and 6d are preferably detachably connected to each other, but can also be permanently connected.

[0057] Fig. Figure 12 shows a sectional view of the distal end of a surgical instrument 1 with an end effector 7 and a manipulator 4 for positioning the end effector 7. The manipulator 4 comprises elements 40a-40d. The proximally arranged element 40a can be attached to the shaft 3 of a surgical instrument 1. For the purpose of attachment, for example, a screw, plug, or snap connection, or any other known connection mechanism, can be used. The proximal end 31 is rotationally fixed to the shaft 3 during operation.

[0058] In this embodiment, element 40a comprises a drive unit 6a, as exemplified in Fig. Figure 7 shows the drive unit 6a. The drive unit serves to drive a first rotatable element 40b, which is arranged at the distal end of element 40a. The two elements 40a, 40b are preferably connected to each other via a plug connection.

[0059] The first rotatable element 40b is rotatable about a first axis of rotation 32, which runs in the longitudinal direction L of the shaft 3. A distally adjoining second rotatable element 40c is rotatable relative to element 40b about a second axis of rotation 33, which is inclined at a predetermined angle to the first axis of rotation 32. A third rotatable element 40d, distally adjoining element 40c, is rotatable relative to element 40c about a third axis of rotation 34, which is inclined at a second angle to the axis of rotation 35. The two angles are preferably equal, but can also be different.

[0060] The individual rotatable elements 40b-40d are each driven by a corresponding drive unit 6a-6c. The first drive unit 6a, for driving the first rotatable element 40b, is integrated into element 40a. The drive unit 6b, for driving the second rotatable element 40c, is located within the first rotatable element 40b. The third drive unit 6c, for driving the third rotatable element 40d, is housed within the third rotatable element 40d. In this variant, no drive unit is provided in the second rotatable element 40c.

[0061] By actuating the first drive unit 6a, the first rotatable element 40b rotates around the first axis of rotation 32. When the second drive unit 6b is actuated, the second rotatable element 40c rotates around the second axis of rotation 33. Finally, by actuating the third drive unit 6c, the third rotatable element 40d rotates around the third axis of rotation 34.

[0062] By rotating the second and third rotatable elements 40c and 40d about their axes of rotation 33, 34, the end effector 7, connected to the distal end of the manipulator 4, can be unwound by a specific angle relative to the longitudinal axis L of the surgical instrument. This angle corresponds to twice the sum of the two angles by which the axes of rotation 33 and 34 are inclined relative to the longitudinal axis L and axis of rotation 35, respectively. If, for example, the two angles are each 22.5 degrees, the end effector 7 can be deflected by up to 90 degrees. Depending on the design of the axes of rotation 33, 34, larger or smaller angles can, of course, also be achieved.

[0063] As in Fig.As can also be seen in Figure 12, the drive units 6a-6c are all identical in construction. As explained above, the optional drive unit 6d can also be identical in construction to the drive units 6a-6c. Likewise, the drive unit 6 can be identical in construction to the drive units 6a-6d. The surgical instrument 1 can therefore be manufactured particularly easily and cost-effectively.

Claims

[1] End effector (7) for a surgical instrument (1), comprising: - a drive unit (6) with an electric motor (12) which rotates a shaft (14, 18), - a rotation-translation gear (29) connected to the shaft (14, 18), which converts a rotational motion of the shaft (14, 18) into a translational motion; and - several working elements (8) of the end effector (7) which are coupled to the rotation-translation gear (29) and are translationally driven by it, wherein the rotation-translation gear (29) comprises several planar cams (36a, 36b) which each engage with and guide at least one translationally driven working element (8, 8a, 8b), wherein the rotation-translation gear (29) comprises several rotatable elements (26a, 26b) with a corresponding planar curve (36a, 36b) which can be actuated independently of each other, characterized by, that the rotation-translation gear (29) includes a clutch (42) that switches between the two rotatable elements (26a, 26b). [2] End effector (7) according to claim 1, characterized by , that the translational movement is perpendicular to an axis of rotation (10) around which the wave (14, 18) rotates. [3] End effector (7) according to any one of the preceding claims, characterized by , that the planar curves (36a, 36b) are designed as helical threads or as helical grooves. [4] End effector (7) according to any one of the preceding claims, characterized by , that the planar curves (36a, 36b) span a planar surface whose surface normal points in the direction of the rotation axis (10) of the shaft (14, 18). [5] End effector (7) according to claim 1, characterized by , that the end effector (7) comprises a reciprocating component (41) which drives the working elements (8) in the closing direction (B). [6] End effector (7) according to claim 5, characterized by , that the restoring component (41) is designed as a spring and acts on the rotation-translation gear (29). [7] End effector (7) according to any one of the preceding claims, characterized by , that the shaft (14, 18) of the drive unit (6) engages with at least one rotating element (26a, 26b) of the rotation-translation gear (29). [8] End effector (7) according to any one of the preceding claims, characterized by , that the end effector (7) comprises at least two working elements (8) which are arranged opposite each other or at an angle to each other and can be moved towards each other or away from each other by a rotational movement of the shaft (14, 18). [9] End effector (7) according to claim 8, characterized by , that at least one working element (8) is designed as an electrosurgical working element. [10] End effector (7) according to any one of the preceding claims, characterized by, that the end effector (7) has a fastening device (5) with which a tool (38) of the end effector (7) can be detachably attached to the drive unit (6). [11] End effector (7) according to any one of the preceding claims, characterized by , that the end effector (7) has a fastening device (5) with which the end effector (7) together with its drive unit (6) can be attached to the shaft (3) of a surgical instrument (1). [12] End effector (7) according to any one of the preceding claims, characterized by , that the end effector (7) includes a second drive unit (6d) with which the end effector (7) can be rotated about the axis of rotation (10) of the shaft (14, 18). [13] End effector (7) according to claim 12, characterized by , that the drive unit (6) for actuating the working element (8) of the end effector (7) is constructed identically to the second drive unit (6d) for rotating the end effector (7). [14] End effector (7) according to any one of the preceding claims, characterized by , that the drive unit (6, 6d) includes an electric motor. [15] End effector (7) according to any one of the preceding claims, characterized by , that the drive unit (6, 6d) includes a gearbox (17). [16] Surgical instrument (1) for use in minimally invasive surgery, with a shaft (3) extending in a longitudinal direction (L), characterized by , that an end effector (7) according to one of the preceding claims is provided on the shaft (3).

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