Steering gear for a surgical instrument and surgical instrument equipped with it

Description

[0001] The invention relates to a steering gear of a surgical instrument and to a surgical instrument having such a steering gear.

[0002] Surgical instruments are known from the prior art that can be guided manually or by a robot using a handle. They have a tool at the distal end of an elongated shaft. This tool can be pivoted relative to the shaft, which defines a main axis, by means of an angular movement mechanism consisting of several interlocking pivoting links. These pivoting links are connected to a multitude of steering wires or cables to achieve sensitive control of the tool tip. For actuation, the steering wires can be attached to a gimbal-mounted swashplate, which can be spatially aligned by a steering gear.

[0003] From US 10,105,128 B2, it is known to operate a gimbal-mounted swashplate connected to a deflection mechanism via steering wires using two parallel rods. For this purpose, the rods have a ball socket at one end for receiving a ball element coupled to the swashplate. At their other end, these ball-joint rods are connected via swivel joints, each with a gear quadrant actuated by a drive gear, in order to move the ball-joint rods linearly back and forth to align the swashplate. However, swashplate control with ball-joint rods is not particularly direct, but rather subject to play and results in an unfavorable force flow. Furthermore, rotation of the swashplate around the shaft axis is not possible.

[0004] For this purpose, DE 10 2019 121 092 A1 proposes a surgical instrument that uses a differential gear with two opposing drive bevel gears and an output bevel gear that meshes with the drive bevel gears and is coupled to the swash plate. In this way, the positioning angles of two drives are transmitted directly to the swash plate to align or angle the tool tip accordingly. Furthermore, the swash plate is cardanically mounted on a rotatable main shaft by means of a universal joint and can therefore rotate with the main shaft around the shaft axis. However, the coaxial arrangement of the two drives, opposite one another in a plane orthogonal to the main axis, requires more space.

[0005] For further prior art, reference can be made to the subsequently published documents WO 2023 / 006684 A1 and WO 2023 / 006685 A1, which fall under Art. 54(3) EPC.

[0006] Based on this prior art, it is the object of the present invention to provide an improved steering gear for a surgical instrument for the spatial alignment of a swash plate.

[0007] This object is achieved by a steering gear having the features of claim 1.

[0008] The further object of providing a surgical instrument with an improved steering gear is achieved by the surgical instrument having the features of independent claim 11.

[0009] Further developments or preferred embodiments are set out in the subclaims.

[0010] According to a first embodiment, the steering gear according to the invention, which is provided and designed for a surgical instrument, has at least two drives for the spatial alignment of a swash plate. The swash plate is rotationally coupled to a main shaft that defines a main axis A about which the main shaft is rotatable. Due to the coupling, the swash plate can rotate together with the main shaft. Furthermore, the swash plate is gimbal-mounted around a center located on the main axis A. According to the invention, the steering gear has at least two linear slides, each of which is arranged displaceably along a guide axis B x parallel to the main axis A and is connected to the at least two drives. Each linear slide is operatively connected to the swash plate via a pair of engagement elements. The engagement elements of the pair are formed by an engagement opening and a lever element.The lever element has a head section at a free end of a rod section for movably receiving in the engagement opening. One of the engagement elements of the pair of engagement elements is located on a circumference of the swash plate, and the other engagement element of the pair of engagement elements is located on a surface section of the respective linear slide facing the swash plate, which is a surface section on a longitudinal side of the linear slide parallel to the guide axis B x. In this way, the head section of each lever element is located on a circumferential line around the swash plate center, since the operative connection of the swash plate to the at least two linear slides consequently has at least two lever elements, so that a pivoting plane of the swash plate is defined by the head sections of the lever elements and the center of the swash plate.

[0011] With the steering gear according to the invention, it is possible to pivot the swashplate in order to control a distal angulation mechanism directly by means of linear drives in two spatial directions, whereby the swashplate can also rotate together with the main shaft. This ensures that the steering wires attached to the swashplate rotate with the main shaft when the main shaft rotates and cannot wrap around the main shaft. The swashplate can rotate with the main shaft both in a neutral position, i.e. in the unarticulated state when the pivot plane of the swashplate is orthogonal to the main axis A, and after articulation in a pivoted position in which the main axis A intersects the pivot plane of the swashplate at an angle other than 90°.To pivot the swashplate from the neutral position, at least one of the linear slides is moved along the guide axis B x parallel to the main axis A, with the lever element, as a rod-shaped force transmission element of the respective engagement element pair, following the movement of the linear slide. With this movement, the position of the head section of the lever element and thus the position of the pivot plane change, so that the swashplate is deflected accordingly around its center relative to the main axis A. The center of the swashplate, around which the swashplate can also rotate due to the coupling to the main shaft, is defined by the intersection of the axes of rotation resulting from the gimbal bearing.

[0012] For the purposes of the invention, "gimbal mounting" refers to any mounting of the swashplate that allows the swashplate, which is rotatably coupled to the main shaft, to pivot in two directions orthogonal to the main axis (tilt and yaw). This includes both conventional mounting variants with two orthogonal pairs of axles and mounting variants with a different number and arrangement of axle elements, provided that these allow movements of the swashplate in two spatial directions orthogonal to the main axis A.

[0013] The index x in the designation of the guide axis B x represents a natural number (1, 2, 3, or 4) and is used here to simplify the designation of the guide axes B x assigned to a linear slide. With index 1, the guide axis B 1 is assigned to a first linear slide. A guide axis B 2 is assigned to a second linear slide, etc.

[0014] According to a further embodiment of the steering gear according to the invention, the head section is a ball head section that has at least a partial spherical shape, or a T-head section that is at least partially cylindrical. In the embodiment of the lever element with the T-head section, it can be provided that the lever element is rotatable about the longitudinal axis of the rod section, or that the T-head section is rotatably mounted on the rod section in order to be able to follow the movement of the linear slides in engagement with the swash plate. A "T-head section" is understood to mean that the cylinder-like T-head section runs orthogonally to the rod section and is arranged centrally on the rod section, so that the rod section and the head section have a T-shape in side view.

[0015] According to a further embodiment of the steering gear according to the invention, the swash plate has the engagement opening, and each linear slide has one of the lever elements. For this purpose, the engagement opening is designed either as a circumferential groove extending along the circumferential edge of the swash plate or as a circumferential shoulder extending along the circumferential edge of the swash plate. The lever element is then arranged on the surface portion of the respective linear slide facing the swash plate, so that the rod portion points radially toward the main axis A, and the head portion of each lever element is movably received in the circumferential groove or in the circumferential shoulder.

[0016] With the circumferential groove or the circumferential shoulder as a common engagement opening for each lever element, complex ball joint rods can be dispensed with to compensate for lateral displacements. In contrast to the circumferential groove, which is limited on both sides, the circumferential shoulder is only limited on one side, with the width of the groove or shoulder being dimensioned according to the guided receptacle / position of the head section of the lever elements. The centers of the head sections of the lever elements, whose rod sections or longitudinal axes point radially to the main axis A, are always located exactly on the pivoting plane of the swashplate thanks to the guide in the circumferential groove or on the circumferential shoulder. If the linear slides are moved, these centers of the head sections move with the lever elements and thus lead to a pivoting of the swashplate.The coupling of the swash plate to the main shaft for joint rotation around the main shaft is easily possible because the circumferential groove or the circumferential shoulder is circumferential.

[0017] In order to enable a planar force transmission when using lever elements with a ball head section, according to a further development of the steering gear according to the invention, the pair of engagement elements can have a sliding block element for each lever element that is designed with a ball head section. This sliding block element is designed to be received in the circumferential groove or the circumferential shoulder and has a ball socket in which the ball head section of the lever element can be movably received. Optionally, sliding block elements that are assigned to the lever elements of adjacent linear slides and are therefore arranged adjacent in the circumferential groove or on the circumferential shoulder can each be connected to one another via an elastic connecting element and together form a clamp element.

[0018] Such a T-slot nut element can be designed in a circular arc, analogous to the course of the circumferential groove / shoulder, with the ball socket for articulated reception of the ball head section preferably being positioned centrally in the T-slot nut element. Lever elements that have a T-head section can dispense with such a T-slot nut element, since the T-head sections transmit force through linear contact, unlike a ball head section, whose force transmission is point-like.

[0019] According to a further embodiment of the steering gear according to the invention, in which the swash plate is designed with the circumferential groove as an engagement opening, the steering gear can have two linear slides, on each of which a lever element is arranged. The arrangement of the lever elements on the linear slides and the arrangement of the two linear slides in relation to the swash plate are coordinated with one another in such a way that two differently oriented pivot axes C 1 , C 2 are defined by each of the two head sections of the two lever elements with the center of the swash plate. This means that an angle is spanned between the two pivot axes C 1 , C 2 which is neither 0° nor 180°. In a preferred embodiment, the two pivot axes C 1 , C 2 run orthogonal to one another when the swash plate is in the neutral position, in which the swash plate is orthogonal to the main axis A in the undeflected state.

[0020] According to an alternative embodiment of the steering gear according to the invention, in which the swash plate with the circumferential shoulder is designed as an engagement opening, the steering gear has three linear slides, each with a lever element, and three drives connected to the linear slides. The arrangement of the lever elements on the linear slides and the arrangement of the three linear slides relative to the swash plate are coordinated such that three differently oriented pivot axes C 1 , C 2 , C 3 are defined by each of the three head sections of the three lever elements with the center of the swash plate.In a preferred embodiment, the three head sections of the three lever elements are arranged as far as possible at the same distance from the center of the swash plate and as evenly spaced from one another as possible, so that the three pivot axes C 1 , C 2 , C 3 each have an angle of approximately 120° ± 10° to one another and add up to 360° when the swash plate is in the neutral position.

[0021] In this embodiment, the head sections of the three lever elements lie in the corners of an equilateral triangle, with the pivot axes C 1 , C 2 , C 3 corresponding to the perpendicular bisectors of the equilateral triangle. The center of the swashplate, around which the swashplate is pivoted, corresponds to the intersection point of the perpendicular bisectors in this equilateral triangle. Since in this embodiment the pivot plane is already defined by the three head sections, this arrangement simultaneously embodies the cardanic mounting of the swashplate, so that additional elements for a cardanic mounting of the swashplate can be omitted here. However, alternative embodiments to this preferred arrangement are also conceivable if, for example, the installation space design does not permit an evenly distributed arrangement of the three head sections.In alternative arrangements that are also functional, the head sections of the lever elements can therefore also be located in the corners of any isosceles or irregular triangle, with the intersection point of the perpendicular bisectors of the triangle corresponding to the center of the swashplate.

[0022] Thus, a right or acute angle can also exist between two of the three pivot axes, so that at least one or each of the two pivot axes forms an obtuse angle with the third pivot axis. For example, if a right or acute angle between two of the pivot axes lies in the range of 10° and 90°, in the case of an isosceles arrangement of the head sections, an obtuse angle in the range of 135° to 175° results between each of the two leg waxes and the third pivot axis, so that the angles add up to 360°. The angle dimensions are to be understood only as examples and are not intended to limit the scope of protection. A minimum acute angle between two of the three pivot axes results when two of the three head sections are arranged next to each other on the circumferential shoulder, and therefore depends on the diameter of the head sections and their distance from the center of the swash plate.In principle, it is also conceivable that two of the three swivel axes span an obtuse angle (> 180°), so that at least one of these two swivel axes spans an acute angle with the third swivel axis.

[0023] According to yet another alternative embodiment of the steering gear according to the invention, wherein the swashplate is also designed with the circumferential shoulder as an engagement opening, the steering gear has four linear slides, each with a lever element. The arrangement of the lever elements on the linear slides and the arrangement of the four linear slides in relation to the swashplate are coordinated such that two of the lever elements are arranged opposite one another. Two pivot axes C 1 , C 2 , which are defined by the head sections of opposite lever elements with the center of the swashplate, then run orthogonally to one another. Two drives are connected in pairs to the linear slides of opposite lever elements. This is sufficient because the linear slides of opposite lever elements are controlled in exactly opposite directions by the same drive via a reversing gear to align the swashplate.In principle, however, if there is sufficient installation space, it is also possible to use a separate drive for each of the four linear slides.

[0024] According to yet another alternative embodiment of the steering gear according to the invention, at least two of the lever elements are arranged on the swash plate, with the associated engagement openings being present on at least two linear slides. The lever elements, which are formed with the ball head portion, extend radially from the peripheral edge of the swash plate. And of the at least two linear slides, a first linear slide has a circular arc groove extending around the main axis A as an engagement opening in the surface portion facing the swash plate. The ball head portion of a first of the lever elements is movably received in the circular arc groove of the first linear slide.A second linear slide has a cylindrical bore as an engagement opening, which is formed in the surface section facing the swashplate and in which the spherical head section of a second of the lever elements is movably received. The axis of the cylindrical bore in the second linear slide intersects the main axis A orthogonally. The spherical head section of the second lever element can move linearly in this bore and compensate for the varying distance between the lever element and the linear slide when the swashplate is pivoted. The arrangement of the engagement openings on the linear slides and the arrangement of the at least two linear slides in relation to the swashplate are coordinated with the arrangement of the at least two lever elements on the swashplate.This has a central section which is rotationally coupled to the main shaft and rotatably mounted in a steering ring of the swash plate, which has the peripheral edge on which the at least two lever elements are arranged.

[0025] In this way, the central section of the swashplate, to which the steering wires are attached, can be rotated with the main shaft, while the spatial alignment of the swashplate is achieved via the steering ring, which is non-rotatable due to the engagement of the lever elements with the linear slides. This is due to the engagement of the spherical head section of the second lever element in the cylinder bore of the second linear slide, while the head section of the first lever element is guided in the circular arc groove of the first linear slide. A circular arc groove is understood to be a groove bounded on both sides with the shape of a circle, the center of which lies on the main axis A. The circular arc groove thus runs virtually parallel to the peripheral edge of the swashplate when the swashplate is in a neutral position orthogonal to the main axis A.

[0026] For example, in this embodiment the steering gear can have exactly two lever elements on the peripheral edge of the swashplate, which engage with the first and second linear slide. The first and second lever elements, whose ball head sections define two pivot axes C 1 , C 2 with the center of the swashplate, are arranged on the peripheral edge of the swashplate in such a way that the two pivot axes C 1 , C 2 are differently oriented, i.e., they span an angle that is neither 0° nor 180°. It is advantageous if the angle between the two pivot axes C 1 , C 2 lies in a range of 60° to 120°. An orthogonal arrangement of the two lever elements on the peripheral edge of the swashplate is particularly preferred, i.e., the longitudinal axes of the rod sections of the first and second lever elements, which here correspond to the pivot axes C 1 , C 2, run orthogonally to one another.Accordingly, the linear slides are arranged with the engagement openings to match the engagement with the lever elements.

[0027] Furthermore, according to a further embodiment, a steering gear according to the invention can have at least one housing component that provides a linear guide for each linear slide. For example, the linear guide can consist of a guide groove parallel to the guide axis B x being formed in the housing component for each linear slide. Accordingly, each linear slide has at least one guide element on a second longitudinal side parallel to the guide axis B x , which is different from the longitudinal side with the surface section facing the swash plate, which guide element is received in the respective guide groove for longitudinal movement. The second longitudinal side of the linear slide, on which the guide element is formed, can - depending on the design of the housing component - be remote from or adjacent to the longitudinal side of the linear slide with the surface section facing the swash plate.Alternatively, for the longitudinal guidance of the linear slides, a guide element can be formed in the housing component for each linear slide parallel to the guide axis B x in the reverse manner, and each linear slide can have a guide groove on a second longitudinal side of the linear slide, which differs from the longitudinal side with the surface section facing the swash plate, which guide groove slidably receives the guide element.

[0028] According to a further embodiment of the steering gear according to the invention, the surface section facing the swash plate is concavely shaped, wherein the concave surface section preferably corresponds to a cylinder jacket surface section around the main axis A.

[0029] Finally, in a further development of the steering gear according to the invention, it is provided that the drive to which the linear slide is connected is a linear motor or a rotary motor which is connected to the linear slide via a spindle, or a hydraulic or pneumatic cylinder.

[0030] According to a first embodiment, a surgical instrument according to the invention comprises an instrument shaft, a tool at a distal shaft end, and a handle at a proximal shaft end, which handle comprises a steering gear with at least two drives for aligning a swash plate. This swash plate is rotationally coupled to a main shaft rotatable about a main axis A and is cardanically mounted about a center Z lying on the main axis A. Furthermore, the swash plate is connected to a plurality of steering wires that extend along the main axis A through the instrument shaft to a bending mechanism of the tool. The steering gear of the surgical instrument according to the invention is a steering gear according to the invention according to at least one of the previously described embodiments.

[0031] Further embodiments, as well as some of the advantages associated with these and other embodiments, will become clear and easier to understand from the following detailed description with reference to the accompanying figures. Objects or parts thereof that are substantially the same or similar may be provided with the same reference numerals. The figures are merely a schematic representation of an embodiment of the invention. It is understood that the features mentioned above and those to be explained below can be used not only in the respective combination specified, but also in other combinations or on their own, without departing from the scope of the present invention.

[0032] Showing: Fig. 1 is a perspective partial view of a surgical instrument according to the invention with a schematically illustrated handle, Fig. 2 is a perspective view of a steering gear according to a preferred embodiment of the invention, Fig. 3 is a perspective partial view of the steering gear from Fig. 2without showing the swash plate, Fig. 4 is a perspective view of a steering gear according to a further embodiment of the invention, Fig. 5 is a perspective view of the swash plate and linear slides of a steering gear according to a further embodiment of the invention, Fig. 6 is a perspective view of the swash plate and linear slides of a steering gear according to a further embodiment of the invention, Fig. 7 is a perspective view of the swash plate and linear slides of a steering gear according to a further embodiment of the invention, Fig. 8 is a perspective view of the swash plate and linear slides of a steering gear according to a further embodiment of the invention.

[0033] In Fig. 1A surgical instrument 1 with a hollow instrument shaft 2 is shown, wherein a handle 5 arranged at the proximal end 2b of the instrument shaft 2 is shown only schematically. A tool 3 is arranged at the distal end 2a of the instrument shaft 2, which tool 3 is, for example, a tool provided with jaws, as in Fig. 1shown, or it can be an endoscope, an applicator or the like. To actuate the tool 3, e.g. to open and close the jaw parts, the surgical instrument 1 has an actuating element 18 which is mounted axially displaceably in the instrument shaft 2 and which is operatively connected on the proximal side to an actuating unit (not shown) of the handle 5. The actuating unit can be a manually actuated handle part or a structural unit designed for robotic use, i.e. which can also be actuated without manual intervention and which is coupled to a corresponding drive. The actuating element 18 which is mounted axially displaceably in the instrument shaft 2 for actuating the tool 3 is designed as a push / pull rod in the illustration.

[0034] Furthermore, the tool 3 of the surgical instrument 1 can be pivoted relative to the main axis A of the instrument shaft 2 via a deflection mechanism 4 at the distal shaft end 2a. The deflection mechanism 4 consists of pivoting elements that are connected to the steering gear 10 in the handle 5 at the proximal end 2b of the instrument shaft 2 via steering wires 6 that extend through the instrument shaft 2. A movement of the proximal-side steering gear 10 thus causes a corresponding relative movement of the distal-side pivoting elements of the deflection mechanism 4, transmitted by the steering wires 6, and thus a pivoting of the tool 3. Even if the term "steering wires 6" is used here, steering cables can also be used functionally, which is why the term "steering wires 6" used should also be read and understood as a synonym for "steering cable".

[0035] The steering gear 10, for which Fig. 2 to 8different examples are shown, has a swash plate 8 to which the steering wires 6 emerging from the proximal shaft end 2b are attached, as in Fig. 2 and 4 can be seen. The swash plate 8 is coupled for rotation to a main shaft 19 which extends along the main axis A to the proximal end 2b of the instrument shaft 2. The instrument shaft 2 is rotatably mounted at its proximal end 2b by means of bearings 20 in a through-opening 15b of the housing component 15 of the steering gear 10. The main shaft 19 extends on the proximal side through a further through-opening 15b in the housing component 15 and is operatively connected to a rotation drive 17. Due to the rotational coupling of the main shaft 19 to the swash plate 8, the tool 3 at the distal shaft end 2a can also be rotated about the main axis A of the instrument shaft 2 without the steering wires 6 becoming twisted.

[0036] For pivoting about two spatial axes orthogonal to the main axis A, the swashplate 8 is cardanically mounted about a center Z that lies on the main axis A. In a conventional cardanic bearing with two orthogonal pairs of axes, the center Z lies at the intersection point of the two pairs of axes and can correspond to the swashplate center or swashplate center of gravity.

[0037] In order to pivot the gimbal-mounted swash plate 8 spatially around its center Z, the steering gear 10 has, depending on the embodiment, two linear slides 9 ( Fig. 2 to 6 ) or three or four linear slides 9 ( Figs. 7, 8 )which are operatively connected to the swash plate 8. The linear slides 9 are connected to drives 16, so that the steering wires 6 for pivoting the distal-side pivoting elements of the deflection mechanism 4 or the tool 3 can be controlled precisely, sensitively in the smallest steps, and also reproducibly.

[0038] In the Fig. 2 to 4 In the example shown, the swash plate 8 has a central through-opening (unlabeled) concentric with the main axis A, in which a universal joint disc 7 is arranged, which in turn has a through-opening (unlabeled) through which the main shaft 19 extends. The universal joint disc 7 is pivotally connected to the swash plate 8 via a first pair of axles. The universal joint disc 7 is pivotally connected to the main shaft 19 via a second pair of axles, which are arranged orthogonally to the first pair of axles, as can be clearly seen in the illustration of Fig. 3without a swashplate. The intersection point of the two pairs of axes, which defines the center Z of the swashplate, is located at the center of the through-hole of the universal joint disk 7, which also corresponds to the center of the through-hole of the swashplate 8. The cardanic bearing with the universal joint disk 7 also ensures the rotational coupling of the swashplate 8 to the main shaft 19 via the two pairs of axes.

[0039] Not shown are alternative designs of the swashplate's gimbal mounting. These could, for example, be designed as an external gimbal mounting with an outer bracket (instead of a closed ring) that is recessed in the area of ​​the linear slides and connected to an inner ring via a first pair of axles. This ring is connected to a peripheral section of the swashplate via a second pair of axles orthogonal to the first pair of axles. A central swashplate section, to which the steering wires are attached and which is coupled for rotation to the main shaft, is then rotatably mounted in the peripheral section of the swashplate.

[0040] The steering gear 10 of the examples in Fig. 2 to 6has two linear slides 9, which are arranged parallel to the rotary drive 17 of the main shaft 19. Each linear slide 9 can be moved independently along a guide axis B 1 , B 2 parallel to the main axis A by connecting it to a drive 16. The drives 16, with which the linear slides 9 are actuated, can also be rotary motors 16, as in Fig. 2 and 3 For this purpose, the rotary motors 16 are each connected via a spindle 14 to the respective linear slide 9, which for this purpose has a spindle bore 9c along the respective guide axis B 1 , B 2 . As an alternative to a rotary motor with a spindle, a linear motor or a hydraulic or pneumatic cylinder, for example, can be used as the drive 16.

[0041] In order to transmit the movement of the respective linear slide 9 to the swash plate 8 in order to pivot the latter about its center Z, each linear slide 9 is operatively connected to the swash plate 8 via a pair of engagement elements. The engagement elements of a pair of engagement elements can be designed in different ways, as described below. However, each pair of engagement elements has, as one of the engagement elements, a lever element 12 with a head portion 12a, 12b, which is movably received in an engagement opening 11, 11a, 11b, 11c, which represents the other engagement element. One of the engagement elements of the pair of engagement elements is located on a circumference of the swash plate 8, and the other engagement element of the pair of engagement elements is located on a surface portion 9a of the respective linear slide 9 that faces the swash plate 8.In this way, the head sections 12a, 12b of the lever elements 12 are always located on a circumferential line around the center Z of the swash plate 8.

[0042] The surface section 9a, which faces the swashplate 8 and on which the respective engagement element is present, is formed as a concave surface section 9a on a longitudinal side of the linear slide 9, which is parallel to the guide axis B 1 , B 2 . The surface section 9a corresponds to a cylindrical surface section around the main axis A with a radius that is slightly larger than the radius of the swashplate 8. The pivot plane of the swashplate 8 is defined by the center Z of the cardanic bearing and the engagement points of the head sections 12a, 12b at the free end of the rod sections 12c of the lever elements 9.

[0043] For axially parallel guidance of the linear slides 9, a guide groove 15a is formed in the housing component 15 parallel to each guide axis B 1 , B 2, in which guide groove a guide element 9b of the respective linear slide 9 is slidably received. The guide element 9b is formed on the underside of the linear slide 9 as an elongated profile element which extends in the longitudinal direction parallel to the guide axis B 1 , B 2. In a design of the housing component and the linear slide that differs from the exemplary representation, it is alternatively possible for the guide element on the linear slide to be present not on its underside, but on another adjacent side surface which does not have the surface section 9a facing the swash plate 8.

[0044] Furthermore, in an embodiment not shown, the arrangement of the guide element and guide groove on the linear slide and the housing component can also be reversed, i.e., the linear slide has a longitudinal groove and is provided on the housing component with an elongated guide element on which the linear slide can be displaced using the longitudinal groove. In contrast to the combination of guide element and guide groove, the linear guide of the linear slide of a steering gear according to the invention can also comprise other known linear guide elements, such as C-profiles or shafts.

[0045] Apart from the example in Fig. 6 In the steering gears 10, the lever elements 12 are arranged on the linear slides 9, while the corresponding engagement opening is formed on the swash plate 8, namely in the form of a circumferential groove 11 running along the peripheral edge of the swash plate 8 ( Fig. 2 , 4 , 5 )or in the form of a circumferential shoulder 11c running along the peripheral edge of the swash plate 8 ( Figs. 7, 8 ). The circumferential groove 11 or the circumferential shoulder 11c forms a common engagement element for all lever elements 12. Each lever element 12 is arranged on the concave surface section 9a of the respective linear slide 9, so that the rod section 12c points in the radial direction to the main axis A and thus the head section 12a, 12b can be received in the circumferential groove 11 or can come into contact with the circumferential shoulder 11c.

[0046] In this way, the centers of the head sections 12a, 12b are located on a circumferential line around the swash plate center Z due to the guide in the circumferential groove 11 or on the circumferential shoulder 11c and are therefore always exactly in the pivoting plane of the swash plate 8. If the linear slides 9 and thus the lever elements 12 are moved along the respective guide axis B 1 , B 2 parallel to the main axis A, these centers of the head sections 12a, 12b are shifted accordingly and thus lead to the pivoting of the swash plate 8. Because the circumferential groove 11 or the circumferential shoulder 11c is circumferential, the swash plate 8 can still be rotated freely with the main shaft 19. Thus, the swash plate 8 can be pivoted in two directions relative to the main axis A and the attached steering wires 6 can be deflected differently and, on the other hand, can be rotated together with the main shaft 19 so that the tool 3 of the surgical instrument 1 can be Fig. 1at the distal end 2a of the instrument shaft 2 can be angled accordingly and / or rotated around the main axis A.

[0047] In Fig. 4The swashplate 8 is shown in the neutral position, in which the main axis A runs orthogonal to the pivot plane defined by the center Z of the swashplate 8 and the ball head sections 12a, which are accommodated in the circumferential groove 11 of the swashplate 8 and guided on both sides. The arrangement of the two linear slides 9 in relation to the swashplate 8 and the arrangement of the lever elements 12 on the two linear slides 9 are coordinated in the example shown such that two pivot axes C 1 , C 2 , which are defined by the two ball head sections 12a of the two lever elements 12 with the center Z of the swashplate 8, run orthogonal to each other in the neutral position of the swashplate 8. The ball head section 12a has an approximately spherical shape, which, however, as in the examples of Fig. 3 , 7 and 8 can be seen, may be flattened on the side facing the swashplate 8.

[0048] The position of the pivoting plane of the swash plate 8, which is defined by the two pivot axes C 1 , C 2 , is determined by the position of the linear slides 9, whereby the pivoting of the swash plate 8 with respect to the main axis 8 is made possible by the cardanic bearing. By moving one or both linear slides 9 along the respective guide axis B 1 , B 2 , the swash plate 8 is pivoted from the neutral position, as in Fig. 2 or 5 can be seen, which show examples that are similar to Fig. 4 are similar. The steering gear 10 in Fig. 2 differs from Fig. 4by the arrangement of two sliding block elements 13, which improve the force transmission of the lever elements 12 to the swash plate 8 by increasing the contact surface compared to the ball head section 12a. The sliding block elements 13 are designed for guided accommodation in the circumferential groove 11 and have a ball socket 13a for the movable accommodation of the ball head section 12a (cf. illustration without swash plate in Fig. 3 ).The sliding block elements 13 transmit the steering forces of the ball head sections 12a received in the ball sockets 13a to the swash plate 8 through their arrangement in the circumferential groove 11. Since the distance between the two ball head sections 12a varies when the linear slides 9 are actuated, the two sliding block elements 13 in the example shown are connected to each other via a flexible connecting piece 13b to form a type of clamp element. Alternatively, the sliding block elements 13 can be designed independently of one another as individual sliding blocks 13.

[0049] The difference between the steering gears 10 in Fig. 4 and 5 is that the lever elements 12 in Fig. 5 with a T-head section 12b instead of a ball head section 12a as in Fig. 4are formed. The T-head section 12b has a cylindrical shape that resembles a torus section, i.e., a cylinder bent along the cylinder axis, the bending radius of which corresponds to the circumference of the swash plate 8 in the circumferential groove 11. In cross-section, the T-head section 12b has the shape of a circular segment, which leads to a flattened side of the outer surface, on which the T-head section 12b is arranged on the rod section 9c and which points towards the concave surface section 9a of the linear slide 9. With the rounded outer surface, the T-head section 12b thus contacts the swash plate 8 in the circumferential groove 11 along a line. In order that the T-head sections 12b can align in the circumferential groove 11 when the swash plate 8 is pivoted by the respective other linear slide 9, the lever elements 12, which have the T-head section 12b, are rotatably mounted about the longitudinal axis of the rod section 12c in the linear slide 9.

[0050] The alternative versions of the steering gear 10 in Figs. 7 and 8 use a circumferential shoulder 11c as an engagement opening on the swash plate 8, which provides only one-sided contact with the ball head section 12a of the lever element 12. Therefore, three linear slides 9 with three lever elements 12 ( Fig. 7 ) or four linear slides 9 with four lever elements 12 ( Fig. 8 )necessary to define all spatial positions of the swash plate 8. The circumferential shoulder 11c has, similar to an annular flange, a distal-side cylindrical section and a proximal-side disc section with an enlarged diameter that is offset therefrom. The spherical head sections 12a of the lever elements 12 therefore bear distally against the disc section of the circumferential shoulder 11c. In order to secure the engagement of the lever elements 12 on the circumferential shoulder 11c thus delimited on one side, the steering wires 6, which are fastened to the end face of the distal-side cylindrical section, can be tensioned in a defined manner during operation by a tensioning mechanism. As a result, the center Z of the swash plate 8 can be displaced linearly along the main axis A, so that the swash plate 8 is pulled in the distal direction by means of the steering wires 6, so that the circumferential shoulder 11c bears against the head sections 12a.

[0051] In the variant of Fig. 7with three linear sliders 9, three drives (not shown) are provided which are connected to the linear sliders 9 in order to be able to move each linear slider 9 independently along the three guide axes B 1 , B 2 , B 3 for aligning the swash plate 8. The arrangement of the lever elements 12 on the respective linear sliders 9 as well as the arrangement of the three linear sliders 9 in relation to the swash plate 8 are coordinated with one another in such a way that the three head sections 12a with the center Z of the swash plate define three pivot axes C 1 , C 2 , C 3 , which each have an angle of 120° to one another. The center Z of the swash plate 8 results as the center of the circular line on which the three head sections 12a are arranged at equal distances.Since the position of the swash plate 8 with respect to two spatial directions orthogonal to the main axis A is clearly determined by the three head sections 12a and thus the cardanic bearing is provided in the sense of the invention, cardanic bearing elements such as the universal joint disc 7 with the two orthogonal pairs of axes of the example in . Fig. 2 to 4 However, for the rotational coupling of the swash plate 8 with the main shaft 19 (not shown in Fig. 7 ) an alternative bearing concept is required which, on the one hand, allows the transmission of rotation angles of the main shaft to the swash plate 8 without preventing the pivoting of the swash plate 8 relative to the main axis A.

[0052] According to such an alternative bearing concept, the swash plate has a radially inward-pointing pin or a diametrically inward-pointing pin pair in its passage opening, and a corresponding guide groove or two diametrical guide grooves are formed in the main shaft, which extend in the longitudinal direction of the main shaft. The engagement of the pin(s) in the guide groove(s) effects the rotational coupling of the main shaft with the swash plate and simultaneously allows pivoting of the swash plate in two orthogonal spatial directions: pivoting about the axis of the pin / pin pair, since each pin can rotate about its axis in the respective guide groove, and tilting of the pin in a plane that it spannes with the guide groove, which corresponds to pivoting of the swash plate about an axis that is orthogonal to the pin axis and the main axis A.

[0053] In order to avoid the need for a third drive for aligning the swash plate 8, in the example of Fig. 8four linear slides 9 with four lever elements 9 are used. This steering gear 10 accordingly provides four guide axes B 1 , B 2 , B 3 , B 4 , along which the four linear slides 9 can be moved to align the swashplate 8. The arrangement of the lever elements 12 on the four linear slides 9 and the arrangement of the four linear slides 9 in relation to the swashplate 8 are coordinated with one another such that the head sections 12a are arranged at equal distances on a circular line around the center Z of the swashplate 8, so that two head sections 12a are arranged diametrically opposite one another. Accordingly, the two head sections 12a of opposite lever elements 12 each define a pivot axis C 1 , C 2 , which run orthogonally to one another in the neutral position of the swashplate 8 and intersect at the center Z of the swashplate 8.The linear slides 9 of opposite lever elements 12 are not controlled independently of each other, but in exactly opposite directions, as shown in . Fig. 8can be seen from the position of the linear sliders 9 along the guide axis B 1 , B 2 , B 3 , B 4 . The linear slider 9 guided along the first guide axis B 1 (the lever element of which is hidden in the illustration) is offset in the proximal direction, corresponding to the offset in the distal direction of the linear slider 9 guided along the third guide axis B 3 . The same applies to the linear sliders 9 guided along the guide axes B 2 and B 4 . The counter-rotating control of the linear sliders 9 of opposite lever elements 12 can be realized with a reversing gear (not shown) (e.g. using a counter-rotating spindle, etc.), so that the linear sliders 9 of opposite lever elements 12 can each be moved by the same drive, and therefore only two drives are required for four linear sliders.

[0054] In the Fig. 6In the illustrated example of an alternative steering gear 10, the lever elements 12 are arranged on the swash plate 8. The corresponding engagement openings 11a, 11b for the head sections 12a are located on the linear slides 9. In a linear slide 9 guided along the first guide axis B 1, a circular arc groove 11a extending around the main axis A is formed in the concave surface section 9a, in which the ball head section 12a of one of the lever elements 12 is guidably received. The other linear slide 9, guided along the second guide axis B 2, has a cylindrical bore 11b in the concave surface section 9a, the axis of which intersects the main axis A perpendicularly and in which the ball head section 12a of the second lever element 12 is movably received.Since the lever elements 12 in this arrangement would prevent rotation of the swashplate 8 about the main axis A, the swashplate 8 in this embodiment is divided into a circumferential section 8a, on which the lever elements 12 are arranged, and a central section (not shown). This central section is rotatably mounted in the circumferential section 8a and is provided for fastening the steering wires. The cardanic mounting of the central section on the main shaft and its rotational coupling can be achieved by means of a universal joint disc and two crossed axle pairs as described above, which determine the center Z of the swashplate 8. The pivot axes C 1 , C 2 , which are defined by the spherical head sections 12a of the lever elements 12 with the center Z of the swashplate 8, run orthogonally to one another. The lever elements 12 extend radially offset by 90° from the circumferential edge of the circumferential section 8a of the swashplate 8.

[0055] The drawings, the description, and the claims contain numerous features in combination. It is understood that the aforementioned features can be used not only in the respective combination specified, but also in other combinations or on their own, without departing from the scope of the present invention. The present invention provides a steering gear 10 for a surgical instrument 1 and the surgical instrument 1 itself, wherein the steering gear 10 has at least two drives 16 for the spatial alignment of a swash plate 8. The swash plate 8 is rotationally coupled to a main shaft 19, which is rotatable about a main axis A, and is cardanically mounted about a center Z lying on the main axis A. The steering gear 10 has at least two linear sliders 9, each of which is arranged to be displaceable along a guide axis B x parallel to the main axis A and is connected to the at least two drives 16.Each linear slide 9 is operatively connected to the swash plate 8 via a pair of engagement elements, which have, as engagement elements, an engagement opening 11, 11a, 11b, 11c and a lever element 12, which has a head section 12a, 12b at a free end of a rod section 12c for movably receiving in the engagement opening 11, 11a, 11b, wherein a pivoting plane of the swash plate 8 is defined by the head sections 12a, 12b of the lever elements 12 and the center Z of the swash plate 8. One of the engagement elements of the pair of engagement elements is located on a circumference of the swash plate 8 and the other engagement element of the pair of engagement elements is located on a surface section 9a of the respective linear slide 9 facing the swash plate 8, which is a surface section 9a on a longitudinal side of the linear slide 9 parallel to the guide axis B x. LIST OF REFERENCE SYMBOLS

[0056] 1Surgical instrument 2Instrument shaft 2a, 2bDistal, proximal shaft end 3Tool 4Angling mechanism 5Handle 6Steering wire 7Universal joint disc 8Swash plate 8aSteering ring 9Linear slider 9a, 9b, 9cConcave surface section, guide element, spindle bore 10Steering gear 11Circumferential groove 11a, 11bCircular groove, cylinder bore 11cCircumferential shoulder 12Lever element 12a, 12b, 12cBall head section, T-head section, rod section 13Sliding block element 13a, 13bBall socket, connecting piece 14Slider spindle 15Housing component 15a, 15bGuide groove, through opening 16Linear slider drive 17Rotation drive 18Pull rod 19Main shaft 20Bearing AMain axis B 1, 2, 3, 4 Guide axis C 1, 2, 3 Swivel axis ZSwashplate center

Claims

1. Steering gear (10) for a surgical instrument (1), the steering gear (10) comprising at least two drives (16) for spatially aligning a swash plate (8), the swash plate (8) being rotationally coupled to a main shaft (19), which is rotatable about a main axis (A), and being cardanically mounted about a center (Z) which lies on the main axis (A), characterized in that the steering gear (10) comprises at least two linear slides (9), each of which is arranged so as to be displaceable along a guide axis (Bx) parallel to the main axis (A) and is connected to the at least two drives (16), each linear slide (9) being operatively connected to the swash plate (8) via an engagement element pair which, as engagement elements, has an engagement opening (11, 11a, 11b, 11c) and a lever element (12) which, at a free end of a rod portion (12c), has a head portion (12a, 12b) for movable accommodation in the engagement opening (11, 11a, 11b), a pivoting plane of the swash plate (8) being defined by the head portions (12a, 12b) of the lever elements (12) and the center (Z) of the swash plate (8), and one of the engagement elements of the engagement element pair being arranged on a circumference of the swash plate (8) and the other engagement element of the engagement element pair being provided on a surface portion (9a) of the relevant linear slide (9) which faces the swash plate (8) and is a surface portion (9a) on a longitudinal side of the linear slide (9) parallel to the guide axis (Bx).

2. Steering gear (10) according to claim 1, characterized in that the head portion is a spherical head portion (12a) which has a spherical shape at least in part, or a T-head portion (12b) which is cylindrical at least in part.

3. Steering gear (10) according to claim 1 or 2, characterized in that the swash plate (8) comprises the engagement opening (11, 11a, 11b, 11c) and each linear slide (9) comprises one of the lever elements (12), the engagement opening (11, 11a, 11b, 11c) being a circumferential groove (11) that extends circumferentially along the circumferential edge of the swash plate (8) or a circumferential shoulder (11c) that extends circumferentially along the circumferential edge of the swash plate (8), and the lever element (12) being arranged on the surface portion (9a) of the relevant linear slide (9) that faces the swash plate (8), so that the rod portion (12c) points in the radial direction to the main axis (A), and the head portion (12a, 12b) of each lever element (12) being movably accommodated in the circumferential groove (11) or in the circumferential shoulder (11c).

4. Steering gear (10) according to claim 3, characterized in that the engagement element pair further comprises, for each lever element (12) with the ball head portion (12a), a sliding block element (13) which is designed to be accommodated in the circumferentially extending circumferential groove (11) or in the circumferentially extending circumferential shoulder (11c) and has a ball socket (13a) which is designed to movably accommodate the ball head portion (12a).

5. Steering gear (10) according to claim 3 or 4, characterized in that the swash plate (8) with the circumferentially extending circumferential groove (11) is designed as an engagement opening (11, 11a, 11b, 11c) and the steering gear (10) comprises two linear slides (9), the arrangement of the lever elements (12) on the two linear slides (9) and the arrangement of the two linear slides (9) in relation to the swash plate (8) being coordinated with one another in such a way that two differently oriented pivot axes (C1, C2) are defined by the two head portions (12a, 12b) of the two lever elements (12) with the center (Z) of the swash plate (8), with the two pivot axes (C1, C2) preferably extending orthogonally to one another.

6. Steering gear (10) according to claim 3 or 4, characterized in that the swash plate (8) with the circumferentially extending circumferential shoulder (11c) is designed as an engagement opening (11, 11a, 11b, 11c) and the steering gear (10) comprises three linear slides (9) which are connected to three drives (16), the arrangement of the lever elements (12) on the three linear slides (9) and the arrangement of the three linear slides (9) in relation to the swash plate (8) being coordinated with one another in such a way that three differently oriented pivot axes (C1, C2, C3) are defined by the three head portions (12a, 12b) of the three lever elements (12) with the center (Z) of the swash plate (8), with the three pivot axes (C1, C2, C3) preferably each extending at an angle of 120° ± 10° to one another.

7. Steering gear (10) according to claim 3 or 4, characterized in that the swash plate (8) with the circumferentially extending circumferential shoulder (11c) is designed as an engagement opening (11, 11a, 11b, 11c) and the steering gear (10) comprises four linear slides (9), the arrangement of the lever elements (12) on the four linear slides (9) and the arrangement of the four linear slides (9) in relation to the swash plate (8) being coordinated with one another in such a way that two pivot axes (C1, C2), which are each defined by two of the head portions (12a, 12b), of which the lever elements (12) are arranged opposite one another, with the center (Z) of the swash plate (8) extend orthogonally to one another, the linear slides (9) of opposite lever elements (12) being connected in pairs to the two drives (16).

8. Steering gear (10) according to claim 2, characterized in that - at least two of the lever elements (12) are arranged on the swash plate (8), which extend from the circumferential edge of the swash plate (8) in the radial direction and are formed with the spherical head portion (12a), and - of the at least two linear slides (9), a first linear slide (9) has a circular arc groove (11a) extending about the main axis (A) as an engagement opening (11, 11a, 11b, 11c) and a second linear slide has a cylinder bore (11b) as an engagement opening (11, 11a, 11b, 11c), which are formed in the surface portion (9a) of the relevant linear slide (9) that faces the swash plate (8), the ball head portion (12a) of a first of the lever elements (12) being movably accommodated in the circular arc groove (11a) of the first linear slide (9) and the ball head portion (12a) of a second of the lever elements (12) being movably accommodated in the cylinder bore (11b) of the second linear slide (9), and the arrangement of the engagement openings (11a, 11b) on the linear slides (9) and the arrangement of the at least two linear slides (9) in relation to the swash plate (8) being coordinated with the arrangement of the at least two lever elements (12) on the swash plate (8), and the swash plate (8) having a central portion which is rotationally coupled to the main shaft (19) and rotatably mounted in a steering ring of the swash plate (8), which steering ring has the circumferential edge on which the at least two lever elements (12) are arranged.

9. Steering gear (10) according to any of claims 1 to 8, characterized in that the steering gear (10) comprises at least one housing component (15), which provides a linear guide for each linear slide (9), and / or the surface portion (9a) is a concave surface portion (9a), which preferably corresponds to a cylinder surface portion about the main axis (A).

10. Steering gear (10) according to any of claims 1 to 9, characterized in that the drive (16) to which the linear slide (9) is connected is a linear motor, a rotary motor (16) connected to the linear slide (9) via a spindle (14), or a hydraulic or pneumatic cylinder.

11. Surgical instrument (1) comprising an instrument shaft (2), a tool (3) at a distal shaft end (2a), and a handle (5) at a proximal shaft end (2b), the handle (5) having a steering gear (10) with at least two drives (16) for aligning a swash plate (8) which is rotationally coupled to a main shaft (19), which is rotatable about a main axis (A), and the swash plate (8) being cardanically mounted about a center (Z) which lies on the main axis (A) and being connected to a plurality of steering wires (6) which extend along the main axis (A) through the instrument shaft (2) to a bending mechanism (4) of the tool (3), characterized in that the steering gear (10) is a steering gear (10) according to at least one of claims 1 to 10.