Surgical instruments and actuators therefor

Abstract

The present invention provides an actuator (10) for a surgical instrument (1) and corresponding surgical instrument (1), the surgical instrument (1) comprising a hollow shaft (2) having a tool (6) at a distal end (5) of the shaft (2), the tool (6) having at least two jaws (7), and an actuator (10) disposed at a proximal end (3) of the shaft (2) and operatively connected to an actuation rod (8) mounted on the shaft (2) for axial movement in the direction of a longitudinal axis (A) of the shaft (2) to open and close the jaws (7). The actuator (10) comprises a cam wheel (11) having a curved track (12) and a scanner pin (13), the scanner pin (13) being guided in the curved track (12) at an interlocking section (13.1) and operatively connected to an actuation rod (8) at a connection section (13.2), the actuator (10) comprising a bearing arrangement (20) providing a forced guidance of the scanner pin (13) along a longitudinal axis (A), such that upon rotation of the cam wheel (11) about an axis of rotation (B) of the cam wheel (11) extending perpendicular to the longitudinal axis (A), a linear movement along the longitudinal axis (A) of the scanner pin (13), guided in the curved track (12), and of the actuation rod (8) operatively connected to the scanner pin (13) is provided.

Description

[Technical Field]

[0001] The present invention relates to a surgical instrument and an actuator for the surgical instrument for opening and closing tool jaws at a tool tip of the surgical instrument. [Background technology]

[0002] Surgical instruments that can be guided manually or robotically and have a hollow shaft with a tool tip at the distal end of the shaft and a handle or actuation unit located at the proximal end of the shaft are known from the prior art. The tool at the tool tip may be a grasping or cutting tool with at least two grasping or cutting elements (collectively referred to as jaws), and the surgical instrument comprises an actuation mechanism for opening and closing the jaws, the actuation mechanism typically comprising an actuation element axially mounted within the shaft and operatively connected to the actuation unit proximally.

[0003] The surgical system disclosed in U.S. Pat. No. 10,105,128 describes an actuation mechanism for opening and closing such jaws. For this purpose, a rope pulley is used, with a pull rope forming the actuation element. This actuation mechanism requires an opening element and a closing element at the tool tip, each of which is secured by a pull cable. The jaws are then opened and closed by retracting the opening element or the closing element relative to the other element in the direction of the shaft using the associated pull rope.

[0004] Other actuation mechanisms use pull / push rods as the actuating elements, which are more stable than pull ropes, can transmit both pulling and pushing motions, are simple to assemble, and can also be used to transmit rotational motion.

[0005] WO 2014 / 004242 describes a surgical instrument with an axially movable pull rod for opening and closing tool jaws at the tool tip. The actuation mechanism for the pull rod includes a movable drive bracket connected on one side to a proximal end of the pull rod and operatively connected on the other side to a drive coil, actuation of the coil resulting in movement of the retaining bracket and thus axial displacement of the pull rod. Summary of the Invention [Problem to be solved by the invention]

[0006] Based on this prior art, it is an object of the present invention to provide an improved actuation mechanism for opening and closing tool jaws at the distal tool tip of a surgical instrument. [Means for solving the problem]

[0007] This problem is solved by an actuation device with the features of claim 1.

[0008] The further problem of providing a surgical instrument with an improved actuation mechanism is solved by a surgical instrument with the features of independent claim 9.

[0009] Developments / preferred embodiments are set forth in the dependent claims.

[0010] According to a first embodiment of the actuator according to the present invention, an actuator is provided for a surgical instrument, the surgical instrument comprising a hollow shaft with a tool at its distal end, the tool having at least two jaws. The actuator is disposed at the proximal end of the shaft. The actuator is operatively connected to an actuation rod, which is axially movably attached to the shaft in the direction of the shaft's longitudinal axis to open and close the jaws. The present invention also contemplates that the actuator comprises a cam wheel having a curved track and a scanner pin. The scanner pin comprises an interlocking section and a connecting section, and the scanner pin extends parallel to the rotation axis of the cam wheel, is guided in the curved track in the interlocking section, and is operatively connected to the actuation rod in the connecting section, which extends vertically, i.e., perpendicular to the rotation axis of the cam wheel. Furthermore, the actuator comprises a bearing device that provides positive guidance of the scanner pin along the longitudinal axis. Here, "positive guidance" refers to mechanical guidance of the scanner pin by the bearing device, limiting the scanner pin's mobility to one degree of freedom, i.e., back and forth movement along the longitudinal axis. Thus, when the cam wheel rotates about its axis of rotation, it provides linear motion along the longitudinal axis of the scanner pin, which is guided in the curved track, and thus of the actuation rod operatively connected to the scanner pin. Thus, linear motion of the actuation rod operatively connected to the scanner pin is achieved by appropriate alignment of the cam wheel with respect to the actuation rod. In this manner, rotational motion of the drive motor is converted into linear motion of the actuation rod, and advancement and retraction of the actuation rod can actuate the jaws for opening and closing.

[0011] In order to achieve a high closing force of the jaw mechanism, the invention allows for the transmission ratio between the drive motor and the jaws to be selected as high as possible, which is achieved in a preferred embodiment of the actuating device according to the invention by providing that the cam wheel has a drive rim along at least a certain circumferential portion, which drive rim is operatively connected via a drive shaft to a drive element actuatable by the motor. The design of the drive rim relative to the drive element can be selected so that an adjustment of the transmission of force and speed for moving the actuating rod adapted to the respective application of the instrument is achieved.

[0012] In a preferred embodiment of the actuator according to the invention, the drive rear may be a gear rear and the drive element engaging therewith may be a pinion, and the transmission ratio can be set to a desired level by the ratio of the diameters or number of teeth of the pinion and the gear rear. The toothed rim may be a spur gear rim, a bevel gear rim or a worm gear rim, and a corresponding spur gear, bevel gear or worm shaft is provided as the pinion.

[0013] However, the term "drive rim" should not be understood here as being limited to a toothed rim, but also includes drive variants with a similar function, such as traction means pulleys, which are operatively connected by a traction means to a drive element which is also configured as a traction means pulley, and the transmission ratio can be adjusted by selecting the diameter of the traction means pulley.

[0014] A further embodiment of the actuator according to the invention contemplates that the curved track extends over a portion of an Archimedes spiral about the axis of rotation, and opposite directions of rotation of the cam wheel result in opposite linear motion of the scanner pin along the longitudinal axis, and thus back and forth motion of the actuation rod.

[0015] In an Archimedes spiral, the radius increases proportionally to the rotation angle during rotation, i.e., the slope (the increase in radius depending on the rotation angle) is constant, so a scanner pin guided in such a curved track moves uniformly linearly. Therefore, the range and speed of linear movement are determined by the length and slope of the curve. When the cam wheel is moved in a first rotational direction, the scanner pin guided in the curved track is moved linearly in a first direction along the longitudinal axis, thereby advancing, for example, an actuation rod to open the jaws of a surgical instrument. Correspondingly, in this example, closing the jaws is achieved by retracting the actuation rod, which linearly moves the scanner pin in a second direction along the longitudinal axis opposite the first direction, which in this embodiment is achieved by changing the rotation direction of the cam wheel to the second rotational direction opposite the first rotational direction. Naturally, the actuation mechanism can also be designed to open the jaws by retracting the actuation rod and close the jaws by advancing the actuation rod. In this embodiment, the drive rim may not need to be a full circumference if the range of motion of the scanner pin guided in the curved track does not require one complete revolution of the cam wheel.

[0016] As an alternative to a curved track shape corresponding to a portion along an Archimedean spiral about the rotation axis, the curved track may be based on a portion of a spiral with a variable slope, i.e., a variable radius increase depending on the rotation angle, such that opposite rotation directions of the cam wheel about the rotation axis cause opposite linear motion of the scanner pin along the longitudinal axis. Non-limiting examples include a logarithmic spiral, a hyperbolic spiral, or a Fermat spiral, but also combinations of all of the above, including a clothoid or an Archimedean spiral. "Combination" here means that the curved track can be divided into two or more sections, and the sections can be based on different spiral types with different slope functions. The variable slope of the curved track allows for independent control of the speed and force-distance ratio of the linear motion. The slope of the curved track can affect the adjustment speed as well as the distributed force or transmission ratio. A flat slope of the curved track results in slower linear motion with greater force (for a constant rotation speed of the cam wheel). The greater the gradient of the curved track, the faster the linear movement and the smaller the force. When using a spiral with a non-constant gradient, for example, it can be adjusted so that a constant rotational movement has a large spiral gradient at the beginning, generating a fast linear movement, and a flat spiral gradient at the end, generating a slow linear movement but a high closing force. However, other forms of gradient of the curved track are also possible, even in the opposite direction.

[0017] As an alternative to the above-described embodiment, the actuator may be configured to provide advancement and retraction of the scanner pin along the longitudinal axis for advancing and retracting the actuation rod without changing the direction of rotation of the cam wheel. To this end, in a further embodiment of the actuator according to the present invention, the curved track extends over at least two sections, the sections having different slopes to form a closed curved track. Here, the first section is configured for linear movement of the scanner pin in a first direction along the longitudinal axis upon rotation of the cam wheel about the rotation axis in a predetermined rotational direction. The second section is configured for linear movement of the scanner pin in a second direction opposite to the first direction along the longitudinal axis upon further rotation of the cam wheel about the rotation axis in the predetermined rotational direction. Again, at least one section may extend along an Archimedes spiral, and / or the speed and force-distance ratio of the linear movement may be independently controlled by the variable slope of the curved track, thereby allowing, for example, a different speed and force-distance ratio to be selected for the jaw closing operation by movement of the actuation rod than for the jaw opening operation.

[0018] In a further embodiment of the actuation device according to the invention, the scanner pin is supported and guided in the curved track so that it is smoothly guided in the curved track and does not undergo rotational movement. For this purpose, one or more (radial) bearings, for example, rolling bearings, can be arranged in the interlocking section of the scanner pin, via which the scanner pin is supported in the curved track. Preferably, the interlocking section can be defined on both sides by shaft steps to provide one stop for each of the two bearings. Alternatively, by using a suitable material combination, the scanner pin can also be guided in the curved track by sliding bearings.

[0019] Basically, in one embodiment of the actuation device according to the invention, it is conceivable that the scanner pin for transmitting the linear movement is directly connected, for example screwed, welded or molded integrally, to the actuation rod, and that a bearing device of the actuation device ensures a forced guidance of the scanner pin and / or the actuation rod along the longitudinal axis. A further embodiment of the actuation device according to the invention provides that the operational connection between the scanner pin and the actuation rod is provided by a bearing device, which has a longitudinal bore through which the actuation rod extends and an interlocking bore perpendicular to the longitudinal bore and in which the connecting section of the scanner pin is accommodated.

[0020] Here, the bearing device is arranged axially movably along the longitudinal axis in a guide block having a bearing opening along the longitudinal axis. Preferably, the guide block can provide a sliding support for the bearing device within the bearing opening. For longitudinal movement, the bearing device and the bearing opening of the guide block are formed in a cylindrical or prismatic shape with corresponding sides parallel to the longitudinal axis, and the guide block has a through opening or guide groove for the scanner pin that communicates with the bearing opening and extends parallel to the longitudinal axis. In this way, the bearing device is fixed with respect to all degrees of freedom except for back-and-forth movement along the longitudinal axis. Furthermore, the corresponding non-circular cross-sectional shapes of the bearing device and the bearing opening, which prevent rotation of the bearing device about the longitudinal axis, allow for an alternative embodiment in which the scanner pin, which is prevented from rotating about the longitudinal axis by guiding in the through opening or guide groove of the guide block, is not fixed in a radial interlocking hole.

[0021] When the bearing device is rigidly connected to the actuation rod, the actuation rod can only provide linear movement for opening and closing the jaws, as in the case of a direct connection between the scanner pin and the actuation rod. Therefore, in a preferred embodiment of the actuation device according to the present invention, which advantageously also allows rotational movement of the actuation rod as an additional actuation mechanism, the bearing device is composed of at least two housing parts having a longitudinal bore and a perpendicular interlocking bore, the housing parts being connected at opposite end faces in a plane perpendicular to the longitudinal axis. The opposite end faces, coaxial with the longitudinal bore, have receiving openings, each of which provides a bearing seat for a clamping disk bearing device, which, when axially fixed, provides a rotatable support for the actuation rod within the bearing device to transmit the linear movement of the scanner pin to the actuation rod. For this purpose, in a preferred embodiment, the clamping disk bearing device includes a clamping disk connected to the actuation rod and thus rotatable about the longitudinal axis. Furthermore, the clamping disc bearing arrangement comprises two axial bearings for rotatably decoupling the clamping disc arranged between them from the bearing arrangement, the axial bearings being arranged in bearing seats in the receiving opening of the housing part. The clamping disc is thus axially fixed in the bearing arrangement and can preferably be arranged between two flanges, each flange providing a bearing seat for the bearing of the axial bearing facing the clamping disc.

[0022] A surgical instrument according to the present invention, comprising a hollow shaft, at the distal end of which a tool having at least two jaws is arranged, and at the proximal end of which an actuator is arranged, the actuator being operatively connected to an actuation rod, the actuation rod being attached to the shaft so as to be axially movable in the direction of the longitudinal axis of the shaft for opening and closing the jaws, comprises an actuator in an embodiment according to the present invention.

[0023] Further embodiments, and some of the advantages associated with these and further embodiments, will become clearer and be better understood from the following detailed description taken in conjunction with the accompanying drawings. Objects or parts thereof that are essentially the same or similar may be labeled with the same reference numerals. The figures are merely schematic representations of one embodiment of the present invention. The drawings, this description, and the claims include many feature combinations. Those skilled in the art will be able to consider features individually and combine them in significant further combinations, as appropriate. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 1 is a schematic perspective side view of a surgical instrument. [Figure 2] 1 is a perspective view of a tool tip with the jaws open and a perspective cross-sectional view of an actuation device according to the present invention; FIG. [Figure 3] FIG. 3 is a view corresponding to FIG. 2 with the jaws closed. [Figure 4] 3 is an enlarged perspective cross-sectional view of the actuator of FIG. 2 according to the present invention; [Figure 5] 3 is a perspective, partially cutaway view of the actuation device according to the invention of FIG. 2 at the guide block; [Figure 6] 1 is a perspective detailed view of an actuation device according to the invention; DETAILED DESCRIPTION OF THE INVENTION

[0025] FIG. 1 shows diagrammatically a surgical instrument 1 comprising a hollow shaft 2, a handle or actuation unit 4 (shown only diagrammatically) arranged at the proximal end 3 of the shaft 2, and a tool 6 arranged at the distal end 5 of the shaft, having two jaws 7 configured here as a grasping tool.

[0026] 1 to 3, in which two jaws 7 form a grasping tool, the jaws of the tool of the surgical instrument according to the invention can also be configured for example for cutting. Furthermore, it is conceivable that a grasping tool can have more than two jaws, for example three or more jaws, which can be opened by moving them apart and closed by moving them towards each other.

[0027] The tool 6, which is further pivotable by an articulation mechanism 9 relative to the longitudinal axis A of the shaft 2 with an actuation mechanism (not described here), is actuatable via an actuation rod 8 attached to the shaft 2 so as to be axially slidable in the direction of the longitudinal axis A, the actuation rod 8 being operatively connected on the proximal side to the actuation unit 4 via an actuator 10.

[0028] The actuation unit 4 can be preferably designed for robotic applications and can therefore be a structural unit that can be actuated without manual intervention, which is advantageous for the reproducibility of actuation. Here, an actuation rod 8, axially slidably attached to the shaft 2, for actuating the tool 6, which consists of two jaws 7, is configured as a pull / push rod.

[0029] In Figure 2, the jaws 7 of the tool 6 are open at the distal end of the shaft 2 due to the actuation rod 8 being retracted by the actuator 10 according to the invention, and in Figure 3, the jaws 7 of the tool 6 are closed at the distal end of the shaft 2 after the actuation rod 8 has been advanced by the actuator 10 according to the invention. Here, "retraction" means that the actuation rod 8 moves in the proximal direction (to the right in the figure), while "advancement" means that the actuation rod 8 moves in the distal direction (to the left in the figure).

[0030] The basic concept of an actuator 10 according to the invention in an exemplary embodiment is shown in Figure 6. The actuator 10 comprises a cam wheel 11 having a curved track 12 that extends along a portion of Archimedes' spiral around a rotation axis B of the cam wheel 11, the rotation axis B extending perpendicular to the longitudinal axis A of the surgical instrument. A scanner pin 13 is guided in the curved track 12, extending parallel to the rotation axis B of the cam wheel 11 and attached to an interlocking section 13.1 in the curved track 12 via a bearing 14 in the curved track 12. The length and slope of the curved track 12 depend on the displacement path provided to the actuation rod 8 and the desired displacement speed and can be easily calculated accordingly.

[0031] The connecting section 13.2 of the scanner pin 13 is operatively connected to an actuating rod 8 (not shown in FIG. 6 but shown in FIGS. 2-5, which include the detail of FIG. 6 in cross section) extending along the longitudinal axis A. By fixing the scanner pin 13 with respect to the longitudinal axis A by a bearing arrangement 20, when the cam wheel 11 rotates about the rotation axis B of the curved track 12, the scanner pin 13 accordingly performs a linear movement along the longitudinal axis A. The rotation of the cam wheel 11 is generated by a drive element, here a spur gear pinion 16, which is driven by a motor 18 via a drive shaft 17 and engages with a spur-toothed rim 15 formed around the periphery of the cam wheel 11. The high transmission ratio between the toothed rim 15 and the pinion 16 ensures a high torque for moving the actuating rod and therefore a high closing force of the jaw mechanism.

[0032] Further drive designs (not shown) include, for example, a bevel gear rim or a worm gear rim as the drive rim, and correspondingly, the drive element is a bevel gear or a worm shaft, in order to transmit the adjusting movement of the motor 18 to the cam wheel 11. Alternatively, the drive rim and the drive element can also be formed by a traction means pulley, such as a belt pulley or a toothed pulley, operatively connected by a traction means, such as a toothed belt or chain.

[0033] 2 to 6, the Archimedes' spiral along which the curved track 12 is partially traced is clockwise when viewed from above, i.e. the radius of the spiral increases clockwise, with a first end 12.1 (FIG. 6) of the curved track 12 being closer to the axis of rotation B and a second end 12.2 being closer to the circumference of the curved track 12. Naturally, in an alternative embodiment (not shown), the curved track of an actuation device according to the invention may also run counterclockwise, with the radius of the spiral increasing counterclockwise.

[0034] The illustrated curved track 12 is configured such that when the cam wheel 11 rotates in a first rotational direction, the scanner pin 13 moves linearly in a first direction along the longitudinal axis A, and when the cam wheel 11, rotatably mounted in a bearing 36, rotates in a second rotational direction opposite the first rotational direction, the scanner pin 13 moves linearly in a second direction opposite the first direction along the longitudinal axis A. When the scanner pin 13 is at the second end 12.2 near the circumference of the curved track 12, as also shown in Figures 4 and 6, the actuation rod 8 operatively connected to the scanner pin 13 is retracted to open the jaws 7 of the tool 6 in the illustrated example (Figure 2). If the cam wheel 11 is now driven clockwise about the axis of rotation B, the actuating pin 13 follows the curved track 12 towards its axially proximal first end 12.1, whereby it performs a linear movement along the longitudinal axis A (to the left in the figure), and the actuating rod 8 (see FIG. 3), which is operatively connected to the actuating pin 13, is advanced, whereby the jaws 7 of the tool 6 are closed at the tool tip of the instrument. Naturally, in modifications of the surgical instrument according to the invention (not shown), it is also possible, conversely, for the jaws to be closed by retracting the actuating rod and for the jaws to be opened by advancing the actuating rod.

[0035] Unlike the curved track 12 shown in Figures 2 to 4, which corresponds to a portion of an Archimedes spiral about the axis of rotation B, the curved track of the actuator can also be configured according to an alternative embodiment (not shown) with a variable slope in order to separately control the speed and force-distance ratio of the linear motion.

[0036] Furthermore, variants having closed curved tracks are also contemplated, which allow linear movement of the scanner pin in both directions along the longitudinal axis A, and therefore advancement and retraction of the actuation rod, without changing the direction of rotation of the cam wheel.

[0037] As can be particularly clearly seen in the detailed view of the actuator 10 in Fig. 4, the scanner pin 13 in the illustrated example comprises an interlocking section 13.1, which is bounded on both sides by a shaft step that is formed in accordance with a corresponding change in diameter of the cylindrical scanner pin 13, so that the interlocking section 13.1 has a larger diameter between the shaft steps. In this way, the shaft step forms a stop for each radial bearing 14 at the interlocking section 13.1 of the scanner pin 13, by means of which the scanner pin 13 is supported in the curved track 12 and does not undergo a rotational movement when moving through the curved track 12 upon rotation of the cam wheel 11. Alternatively, bearing variants with a single rolling bearing or two or more rolling bearings, or embodiments as plain bearings, are also conceivable.

[0038] 2 to 4 and 6, the operational connection between the scanner pin 13 and the actuation rod 8 is provided by a connection section 13.2, which is continuous with the interlocking section 13.1 and which connects the scanner pin to a bearing device 20 having a central longitudinal bore 23 for the actuation rod 8 and a perpendicular interlocking bore 24, into which the connection section 13.2 of the scanner pin 13 is preferably accommodated without play. In the illustrated example, the interlocking bore 24 passes completely through the diameter of the first housing part 21 of the bearing device 20 and intersects with the longitudinal bore 23 through which the actuation rod 8 extends. Here, the connection section 13.2 of the actuation pin 13 is dimensioned such that it extends at most as far as the longitudinal bore 23 and does not come into contact with the actuation rod 8, since the actuation rod 8 is arranged rotatably about the longitudinal axis A within the longitudinal bore 23 of the bearing device 20.

[0039] Therefore, in an alternative form not shown, unlike the illustrated example, the interlocking hole may extend only partially through the bearing device 20, for example terminating at or before the longitudinal hole.

[0040] FIG. 5 shows an example of a forced guidance of the scanner pin 13 along the longitudinal axis A provided by the bearing device 20. For this purpose, the bearing device 20, here configured with a circular cross-section, is slidingly supported along the longitudinal axis A in a bearing opening 28 of a guide block 27, which has a corresponding circular cross-section. In the illustrated example, the guide block 27 also has a recess 29 for accommodating the cam wheel 11. A passage opening or guide groove in the guide block 27, which is not visible in the figure, is configured parallel to the longitudinal axis A and between the bearing opening 28 and the recess 29 in the illustrated example. This passage opening or guide groove has a length that corresponds at least to the displacement path that the scanner pin 13, which extends through the passage opening or guide groove to the bearing device 20 accommodated in the bearing opening 28, follows in the curved track 12 as the cam wheel 11 rotates. In this way, the bearing device 20 is fixed with respect to all degrees of freedom except for forward and backward movement in the longitudinal axis. As an alternative to the illustrated example, the bearing device and the correspondingly configured bearing opening in the guide block can also have a cross section that is not circular, for example oval or polygonal, with rotation of the bearing device already being prevented by its shape.

[0041] Due to the rotatable arrangement of the actuation rod 8 in the longitudinal bore 23 of the bearing arrangement 20, the bearing arrangement 20 receives a clamping disk bearing arrangement 30 to transmit the linear movement of the scanner pin 13 to the actuation rod 8 without impeding the rotation of the actuation rod 8. For this purpose, the bearing arrangement 20 has two housing parts 21, 22 in the example shown, which are connected to each other at their opposite end faces in a plane perpendicular to the longitudinal axis A. Naturally, the bearing arrangement of the actuation device according to the invention can also have more than two housing parts and / or separation or connection faces different from those shown in the example shown.

[0042] The opposing end faces of the housing parts 21, 22 are provided with receiving openings coaxial with the longitudinal bore 23 for receiving the clamping disk bearing device 30. The first, distal housing part 21, here, with its interlocking bore 24, together with its receiving opening coaxial with the longitudinal bore 23, provides a bearing seat 25 for a first axial bearing 25 (designed as a ball bearing in FIGS. 2-4). Similarly, the receiving opening of the second, proximal housing part 22 forms a bearing seat 26 for a second axial bearing 35 (designed as a needle bearing in this case). Mounted between the axial bearings 35 are clamping disks 31, each via a flange 32, which is connected to the actuating rod 8. The flanges 32 provide a bearing seat for the bearing shell of the axial bearing 35 facing the clamping disk 31, allowing the clamping disk 31, axially fixed by the flange 32, to rotate together with the actuating rod 8 around the longitudinal axis A within the bearing device 20.

[0043] Alternatives with similar functions of the clamping disc and clamping disc bearing arrangement are easily conceivable and represent obvious modifications of the actuating device according to the invention within the scope of protection.

[0044] The drawings, this specification, and the claims include many feature combinations. Those skilled in the art will appreciate that features may be considered individually and combined in significant additional combinations, as appropriate. The present invention provides an actuator 10 for a surgical instrument 1 and a corresponding surgical instrument 1, the surgical instrument 1 comprising a hollow shaft 2 having a tool 6 at a distal end 5 of the shaft 2, the tool 6 having at least two jaws 7, the actuator 10 disposed at a proximal end 3 of the shaft 2 and operatively connected to an actuation rod 8, the actuation rod 8 being axially movably attached to the shaft 2 in the direction of a longitudinal axis A of the shaft 2 for opening and closing the jaws 7. The actuator 10 comprises a cam wheel 11 having a curved track 12 and a scanner pin 13, the scanner pin 13 being guided in the curved track 12 at an interlocking section 13.1 and operatively connected to an actuating rod 8 at a connection section 13.2, the actuator 10 comprising a bearing device 20 providing forced guidance of the scanner pin 13 along the longitudinal axis A, such that upon rotation of the cam wheel 11 around a rotation axis B of the cam wheel 11 extending perpendicular to the longitudinal axis A, linear movement along the longitudinal axis A of the scanner pin 13 guided in the curved track 12 and of the actuating rod 8 operatively connected to the scanner pin 13 is provided. [Explanation of symbols]

[0045] 1 surgical instruments 2 shafts 3 Proximal end 4 Handle / operating unit 5 distal end 6 Tools 7 Jaw 8 Actuating Rod 9 Joint mechanism 10 Actuating device 11 Cam Wheel 12 Curved Track 12.1, 12.2 Ends close to the axis, ends close to the circumference 13 Scanner Pin 13.1, 13.2 Interlocking Sections, Connecting Sections 14 Radial bearing 15-tooth rim 16 Pinion 17 Drive shaft 18 Motor 20 Bearing device 21, 22 First and second housing parts 23, 24 Longitudinal holes, interlocking holes 25, 26 Housing seat 27 Guide Block 28 Bearing opening 29 Storage opening 30 Clamped disc bearing device 31 Clamp disc 32 flange 35, 36 Axial bearing, radial bearing A longitudinal axis B Cam wheel rotation axis

Claims

1. 1. An actuator (10) for a surgical instrument (1), the surgical instrument (1) comprising a hollow shaft (2) having a tool (6) at a distal end (5) of the shaft (2), the tool (6) having at least two jaws (7), the actuator (10) being disposed at a proximal end (3) of the shaft (2) and operatively connected to an actuation rod (8) mounted on the shaft (2) for axial movement in the direction of a longitudinal axis (A) of the shaft (2) for opening and closing the jaws (7), 1. The actuator (10) comprises a cam wheel (11) having a curved track (12) and a scanner pin (13), the scanner pin (13) being guided in the curved track (12) by an interlocking section (13.1) and operatively connected to the actuation rod (8) by a connection section (13.2), the actuator (10) comprising a bearing device (20) providing forced guidance of the scanner pin (13) along the longitudinal axis (A), wherein upon rotation of the cam wheel (11) about a rotation axis (B) of the cam wheel (11) extending perpendicular to the longitudinal axis (A), a linear movement along the longitudinal axis (A) of the scanner pin (13) guided in the curved track (12) and the actuation rod (8) operatively connected to the scanner pin (13) is provided.

2. 2. The actuation device (10) according to claim 1, characterized in that the cam wheel (11) has a drive rim along at least a predetermined circumferential portion, the drive rim being operatively connected to a drive element actuable by a motor (18).

3. The drive rim is a toothed gear (15) and the drive element engaging with the toothed gear (15) is a pinion (16). or 3. The actuation device (10) according to claim 2, characterized in that said drive rim and said drive element are formed by a traction means pulley operatively connected by a traction means.

4. 4. The actuator (10) of claim 1, wherein the curved track (12) extends over a portion along an Archimedes' spiral about the axis of rotation (B) or has a variable slope, and opposite directions of rotation of the cam wheel (11) about the axis of rotation (B) provide opposite linear movements of the scanner pin (13) along the longitudinal axis (A).

5. 4. The actuation device (10) of claim 1, wherein the curved track (12) extends over at least two sections forming a closed curved track (12), a first section configured for the linear movement of the scanner pin (13) in a first direction along the longitudinal axis (A) upon rotation of the cam wheel (11) about the rotation axis (B) in a predetermined rotational direction, and a second section configured for the linear movement of the scanner pin (13) in a second direction opposite to the first direction along the longitudinal axis (A) upon rotation of the cam wheel (11) about the rotation axis (B) in the predetermined rotational direction.

6. 4. The actuation device (10) according to claim 1, wherein the scanner pin (13) is supported and guided in the curved track (12), wherein at least two bearings (14) are arranged in the interlocking section (13.1) of the scanner pin (13), via which the scanner pin (13) is supported in the curved track (12), and wherein the interlocking section (13.1) is defined on both sides by shaft steps, which provide one stop for each of the two bearings (14).

7. 4. The actuation device (10) according to claim 1, characterized in that the bearing device (20), having a longitudinal hole (23) through which the actuation rod (8) extends and an interlocking hole (24) perpendicular to the longitudinal hole (23) and in which the connection section (13.2) of the scanner pin (13) is accommodated, is arranged axially movably along the longitudinal axis (A) in a guide block (27) having a bearing opening (28) along the longitudinal axis (A), the guide block (27) providing a sliding support for the bearing device (20) in the bearing opening (28).

8. 8. The actuation device (10) according to claim 7, characterized in that the bearing device (20) has at least two housing parts (21, 22), which are connected to each other at opposite end faces in a plane perpendicular to the longitudinal axis (A), and in which receiving openings are formed in the opposite end faces coaxially with the longitudinal bore (23), and which each provide a bearing seat (25, 26) for a clamping disk bearing device (30), and each bearing seat (25, 26) comprises a clamping disk (31) connected to the actuation rod (8) and two axial bearings (35), which are arranged in the bearing seats (25, 26), and the clamping disk (31), which is arranged between two flanges (32), is supported between the axial bearings (35).

9. 1. A surgical instrument (1) comprising a hollow shaft (2) having a tool (6) at a distal end (5) of the shaft (2), said tool (6) having at least two jaws (7), an actuator (10) disposed at a proximal end (3) of the shaft (2) and operatively connected to an actuation rod (8), said actuation rod (8) being axially movably attached to the shaft (2) in the direction of a longitudinal axis (A) of the shaft (2) for opening and closing said jaws (7), A surgical instrument (1), characterized in that the actuation device (10) is an actuation device (10) according to any one of claims 1 to 3.

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