SURGICAL INSTRUMENT AND STEERING GEAR FOR IT

Description

[0001] The invention relates to a surgical instrument and a steering gear therefor.

[0002] Surgical instruments are known from the prior art that can be guided manually or by a robot and that feature tools whose tool tips can be pivoted using 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. Using many thin steering wires compared to a few thicker ones allows for a more even distribution of force in all deflection directions.

[0003] A generic surgical instrument is known, for example, from US 5 454 827, in which the distal-side pivoting members are coupled via four steering wires to a spatially adjustable swash plate arranged on the proximal side in such a way that a movement of the spatially adjustable swash plate causes a corresponding relative movement of the distal-side pivoting members and thus a pivoting of the tool tip, wherein the movement of the spatially adjustable swash plate is carried out manually via a type of joystick which is directly coupled to it.

[0004] The design of the drive for the steering wires with the spatially adjustable swash plate, on which all four steering wires are mounted, has the advantage that this enables a spatially compact design and only one component has to be moved in order to be able to address all steering wires.

[0005] The disadvantage of this known construction is the use of only a small number of steering wires, namely only four, and furthermore the exclusively manual operation of the spatially adjustable disc serving as a drive for the steering wires, which makes a sensitive and reproducible adjustment of the distal swivel members hardly possible.

[0006] US Pat. No. 7,699,855 discloses a surgical instrument with an interface for connecting the instrument to a robotic arm. All drives controlling the instrument are located within the robotic arm. The rotation angles are transmitted from the drives to the instrument via coupling discs in a common separation plane, so that the drive axes are parallel to each other and perpendicular to this plane.

[0007] WO 2014 / 004 242 also describes such an interface, whereby here too the axis-parallel drives are installed in the robot arm.

[0008] The above design is associated with a complex structure and an indirect control system subject to play, as the drives are not directly located in the surgical instrument. Furthermore, the resulting nonlinear transmission behavior of the drive movement to the swash plate is difficult to represent in a software control system.

[0009] US 10,105,128 B2 also discloses a control of such a tool tip; there, this is done via a mechanism that includes toothed disk segments and articulated rods to transmit the movement of the drives to the swash plate.

[0010] DE 10 2019 121 092 A1 describes a medical instrument with a hollow shaft, at the distal end of which an arranged instrument can be pivoted relative to the longitudinal axis of the shaft by means of a joint mechanism. The joint mechanism is connected to a proximal drive via steering wires running in the longitudinal direction of the shaft. The steering wires are mounted on a spatially adjustable disc of the proximal drive. The motorized drive consists of two drive units arranged 180° apart, the drive shafts of which lie on a common central axis, and the spatially adjustable disc is arranged between the two drive units. The drive units are each designed as gears driven by motors, with each of the two gears being designed as a simple drive wheel with only one gear rim.Preferably, the two driven gears of the drive units engage with a third gear which is coupled to the spatially adjustable disc.

[0011] Based on this prior art, the object of the present invention is to provide an improved steering gear for a surgical instrument, which has a drive for the spatially adjustable swash plate with linear transmission behavior. This object is achieved by a steering gear with the features of claim 1. The further object of providing a surgical instrument whose spatially adjustable swash plate is driven by a structurally simple and space-saving steering gear is achieved by the surgical instrument with the features of dependent claim 8.

[0012] Further developments and preferred embodiments of the steering gear and the surgical instrument are set out in the subclaims.

[0013] According to a first embodiment of the steering gear according to the invention for a surgical instrument, wherein the steering gear can be arranged at the proximal end of a hollow shaft defining a longitudinal axis B of the instrument and having a bending mechanism of the surgical instrument at the distal end, the steering gear has two motorized drives and is designed to spatially align a swash plate via the setting angles of the two drives. This swash plate, in turn, is designed to control the distal bending mechanism of the surgical instrument.

[0014] According to the invention, the first drive has a first drive wheel driven by a first motor, which is designed as a double wheel with a first bevel gear ring and a first drive ring. The second drive also has a second drive wheel driven by a second motor, which is designed as a double wheel with a second bevel gear ring and a second drive ring. The swash plate is arranged between the two drive wheels, which have a common axis of rotation A, with the bevel gear rings facing one another. The drive rings of both double wheels are each operatively connected to a pinion, wherein a first pinion, which is operatively connected to the first drive ring, can be driven by the first motor via a first drive shaft, which defines a first drive axis C.A second pinion, which is operatively connected to the second drive ring, is driven by the second motor via a second drive shaft defining a second drive axis C'. The two drive axes C, C' run parallel to each other and parallel to the common rotational axis A of the two drive wheels, allowing the drive axes to be positioned close to the instrument's longitudinal axis B, saving space.

[0015] The motorized drive of the spatially adjustable disc via the steering gear, which, together with the driven double wheels, provides a linear transmission characteristic, allows the distal tool tip to be activated precisely, sensitively, and reproducibly in the smallest steps. The double wheels can be manufactured as a single piece, but it is also possible for the double wheels to consist of a bevel gear and a drive gear that are connected to each other. The combination of the drive gear ring and the bevel gear ring achieves a direct transmission of the movements initiated by the drives to the swash plate.

[0016] In one embodiment of the steering gear according to the invention, the two double wheels can be arranged with respect to the swash plate such that the two drive axes C, C' and the common axis of rotation A of the two double wheels run vertically, i.e. at right angles to the longitudinal axis B of the surgical instrument. To save space, both motors can be arranged next to each other on one side with respect to the longitudinal axis B, perpendicular to it, so that the overall height can be reduced. Depending on the available installation space, an arrangement of the two motors diametrically offset from one another with respect to the longitudinal axis B is also conceivable.

[0017] In an alternative embodiment of the steering gear according to the invention, the two drive wheels can be designed as hollow double wheels and arranged relative to the swash plate such that the common axis of rotation A of the two hollow double wheels is aligned or coincides with the longitudinal axis B of the surgical instrument, and the two drive axes C, C' run parallel to the longitudinal axis B of the surgical instrument. This also enables a space-saving arrangement of the motors near the longitudinal axis—parallel to it.

[0018] In both arrangement variants of the steering gear, the drive rings of the double wheels or hollow double wheels can be gear rings and the pinions can be gears that directly engage or mesh with the drive rings designed as gear rings.

[0019] As an alternative to the operative connection of gear ring and gear wheel, a further embodiment provides that the drive rings of the double wheels or hollow double wheels and the pinions are each designed as pulleys with a circumferential profile for a drive belt, wherein a first drive belt provides the operative connection of the first drive ring with the first pinion and a second drive belt enables the operative connection of the second drive ring with the second pinion.

[0020] Drive belts can be flat, round, V-belts, ribbed V-belts, or toothed belts. The circumferential profile of the drive sprockets and pinions, which are designed as pulleys, can be flat, round, V-belts, ribbed V-belts, or toothed. Timing belts may be preferred because the positive engagement between the timing belt and the tooth profile on the pulleys not only allows high forces to be transmitted with lower pretension, but also prevents slippage, thus ensuring precise control.

[0021] In a chain drive alternative to a belt drive, the drive sprockets of the double wheels or hollow double wheels and the pinions are designed as sprockets for a drive chain, with a first drive chain providing the operative connection between the first drive sprocket and the first pinion, and a second drive chain providing the operative connection between the second drive sprocket and the second pinion. A belt drive may be preferred over a chain drive due to lower costs and smoother running.

[0022] Furthermore, in a further embodiment according to the invention, for controlling the swash plate, the steering gear can be provided with a third gear that meshes with the two bevel gear rings of the two double wheels or hollow double wheels and whose axis of rotation D is at a right angle to the common axis A of the double wheels. In this way, the actuating movements of the drives can be transmitted via the (hollow) double wheels to the third gear and from there to the swash plate, which can thereby be tilted or pivoted about the two axes of rotation A and D. Preferably, the swash plate can also be coupled to a fourth gear that is coupled with the two bevel gear rings of the two double wheels or hollow double wheels and is arranged on the side facing away from the third gear on its axis of rotation D.

[0023] The invention further relates to a surgical instrument. According to a first embodiment of the surgical instrument, it comprises a shaft, an actuating unit arranged at the proximal end of the shaft, and a tool arranged at the distal end of the shaft. The tool has a tool tip that can be angled by means of a distal angling mechanism. The angling mechanism can be controlled or aligned by a swash plate that can be spatially aligned by means of two drives. For this purpose, the surgical instrument comprises a steering gear according to the invention, wherein the two drives are part of the steering gear according to the invention, which is designed to transmit the setting angles of the two drives to the spatial orientation of the swash plate in order to thus control the angling mechanism.

[0024] The steering gear according to the invention allows the surgical instrument to be constructed in a simple and space-saving manner, enabling easy connection to a robotic arm, with the movement of the drives being transmitted linearly to the tool tip. This results in precisely controllable use of the surgical instrument.

[0025] In order to be able to adjust the spatially adjustable swash plate three-dimensionally despite the rotationally fixed coupling with the third gear, which engages with the two bevel gear rings of the two double wheels, i.e. to be able to superimpose the tilting or pivoting movements with a rotation of the swash plate about the longitudinal axis B, a preferred embodiment of the surgical instrument can provide that the swash plate is mounted so as to be rotatable about the longitudinal axis B of the shaft via a bearing ring in a steering ring which is rotationally fixedly coupled to the third gear. For the rotational coupling of the swash plate to a main shaft running coaxially to a longitudinal axis B of the shaft, the swash plate can be gimbal-coupled to the main shaft. Thus, the tool tip can be rotated around the longitudinal axis of the shaft by means of the swash plate in addition to the pivoting or tilting by the two drives by the main shaft relative to the longitudinal axis of the shaft.

[0026] To implement the gimbal mounting of the spatially adjustable swash plate, an embodiment of the surgical instrument according to the invention can provide that the swash plate is pivotably mounted on a universal joint disc via two bearing pins arranged 180° apart. The universal joint disc is pivotably mounted on the main shaft via two bearing pins arranged 180° apart, and the bearing pins of the swash plate and the universal joint disc are arranged 90° apart. The gimbal mounting enables movement in all three spatial axes, allowing the tool tip to be precisely controlled.As an alternative to a universal joint with two pairs of pins crossed at right angles for the cardanic mounting of the swash plate on the main shaft, an advantageous embodiment can provide that the main shaft has two guide grooves in its outer surface, which extend diametrically and along the main shaft, for the cardanic mounting. The swash plate, which is circular in shape with an outer side and an inner side, has two pins arranged diametrically and radially inwardly on the swash plate. Each of the two pins, which are firmly mounted on or in the swash plate, engages in one of the guide grooves formed on both sides of the main shaft, so that a rotation angle of the shaft can be transmitted to the swash plate.This advantageously results in a torsionally rigid connection between the main shaft and the swashplate, which allows for rotational angle transmission even with a large angular misalignment (± 40° and more) and axial misalignment. It is also very compact in design and easy to manufacture and assemble. However, a curved-tooth coupling can also be used for the gimbal mounting of a swashplate on a main shaft, despite a relatively small angular misalignment, a constant velocity joint despite its complex manufacturing and assembly requirements, or a material-to-material coupling, which is often associated with a rotational angle transmission subject to backlash.

[0027] In a further embodiment of the surgical instrument according to the invention, steering wires extend in the longitudinal direction of the shaft and are connected to the swashplate of the steering gear. Preferably, the steering wires can be releasably attached to the swashplate, for example, by means of a clamp connection, so that the steering wires can be easily replaced in the event of damage. Since the swashplate is rotationally coupled to the main shaft and is rotatably mounted by the bearing ring in the steering ring, which is rotationally fixedly coupled to the third gear, this further advantageously prevents the steering wires from twisting when the tool tip is pivoted relative to the longitudinal axis and rotated about the longitudinal axis of the shaft.

[0028] Furthermore, a further embodiment of the surgical instrument according to the invention provides that the fourth gear is coupled to the swash plate via a bearing ring with the steering ring, whereby the fourth gear is freely rotatable relative to the third gear. This fourth gear completes the rotating toothed chain and thus ensures a uniform, backlash-free force distribution.

[0029] In a further embodiment of the surgical instrument according to the invention, an actuating element is axially displaceably mounted in the shaft (and the main shaft) and is operatively connected to the actuating unit on the proximal side. The distal deflection mechanism of the deflectable tool tip consists of pivoting elements arranged at the distal end of the shaft, which are connected to the swash plate via the steering wires running in the longitudinal direction of the shaft.

[0030] In a further embodiment of the surgical instrument according to the invention, the radial distance of the steering wires from the longitudinal axis of the shaft is greater at the swash plate than at the proximal end of the shaft from which the steering wires emerge. The steering wires can extend from the proximal end of the shaft directly to the swash plate, with the steering wires running at an angle to the swash plate other than 90°. Alternatively, a fan-disk disk can be arranged on the main shaft distally in front of the swash plate, which increases the radial distance of the steering wires emerging from the proximal shaft end from the longitudinal axis of the shaft, so that the steering wires run approximately parallel to one another between the fan-disk disk and the swash plate and form an angle of approximately 90° with respect to a disk surface of the swash plate. Due to the smaller installation space requirement, the variant without a fan-disk disk may be preferred.By increasing the radial distance of the steering wires from the longitudinal axis of the shaft, for example from a diameter of 4 mm to a diameter of 18 mm, not only is the assembly and manufacture of the drive of the steering wires equipped with the spatially adjustable disc simplified, but also the adjustment angle of the spatially adjustable disc or, as a result of the enlarged lever, the forces required for bending are reduced in order to achieve a pivoting angle of the tool tip that corresponds to the extent of the diameter increase.

[0031] In order to avoid a collision of the gears with the steering wires and possibly the actuating element when pivoting the third and fourth gears relative to the longitudinal axis of the shaft, recesses for the steering wires and the actuating element can be formed in the gear rims of the third gear and the fourth gear.

[0032] The surgical instrument according to the invention has the advantage that many thin steering wires can be used to control the pivotable tool tip and that this control is sensitive, precise and reproducible due to the motorized drive for the spatially adjustable disc on which the steering wires are mounted on the proximal side.

[0033] 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. An exemplary embodiment of the invention is shown in the drawings. The drawings and the description contain numerous features in combination. Those skilled in the art will expediently also consider the features individually and combine them into meaningful further combinations while adhering to the scope of the claims.

[0034] Showing: Fig. 1 a schematic perspective side view of a medical instrument according to the invention, Fig. 2 a perspective view of the drive according to Fig. 1 in a first embodiment, Fig. 3 a rear view of the drive according to Fig. 2 , Fig. 4 a plan view of the drive according to Fig. 2 , Fig. 5 a plan view of a variant of the drive according to Fig. 2 , Fig. 6 a plan view of another variant of the drive according to Fig. 2 , Fig. 7 a perspective view of the drive according to Fig. 1 in a second embodiment, Fig. 8 a plan view of the drive according to Fig. 7 , Fig. 9 a perspective view of the drive according to Fig. 1 in a third embodiment, Fig. 10 a perspective, partially sectioned detailed view of the swash plate gear.

[0035] In Fig. 1 1 shows a surgical instrument 1 with a hollow shaft 2, which has an actuating unit 4 arranged at the proximal end 3 of the shaft 2, shown only schematically, and a tool tip 6 arranged at the distal end 5 of the shaft 2. The tool tip 6 is connected to an instrument 7, which can be actuated via an actuating element 8 mounted axially displaceably in the shaft 2, which is operatively connected to the actuating unit 4 on the proximal side. The actuating unit 4 can be a manually operable handle or a structural unit designed for robotic use, i.e., one that can also be actuated without manual intervention.

[0036] The instrument 7 of the tool tip 6 can, for example, be a tool provided with jaw parts, as in Fig. 1 shown, or it could be an endoscope, an applicator or the like.

[0037] The tool tip 6 can be pivoted relative to the longitudinal axis 10 of the shaft 2 via a joint mechanism 9, wherein the joint mechanism 9 consists of pivoting members 11 arranged at the distal end of the shaft 5, which are connected via steering wires 12 running in the longitudinal direction B of the shaft 2 to a drive or steering gear 13 arranged at the proximal end 3 of the shaft 2 such that a movement of the proximal-side steering gear 13 causes a corresponding relative movement of the distal-side pivoting members 11 and thus a pivoting of the tool tip 6.

[0038] Even if only the term steering wires 12 is used above and below, steering cables can also be used functionally, which is why the term steering wires 12 should also be read and understood as a synonym for steering cable.

[0039] The actuating element 8, which is mounted axially displaceably in the shaft 2 and is used to actuate the instrument 7, which consists for example of two jaw parts, is designed as a pull / push rod in the embodiments shown.

[0040] The steering gear 13 for the steering wires 12 is designed as a motorized drive 13 in the medical instrument 1 shown in the figures and described below.

[0041] In yet another embodiment of the surgical instrument according to the invention, the swash plate is mounted in a steering ring for rotation about the longitudinal axis B of the shaft. For this purpose, a bearing ring is provided in the steering ring, which is rotationally fixedly coupled to the third gear. This allows the tool tip to be rotated about the longitudinal axis of the shaft in addition to pivoting relative to the longitudinal axis of the shaft, without twisting the steering wires.

[0042] The core of the drive 13 is a spatially adjustable disc or swash plate 14 ( Fig. 3 , 9 , 10 ), on which the steering wires 12 are mounted such that a displacement of the swash plate 14 via the steering wires 12 mounted on the swash plate 14 causes a pivoting of the tool tip 6. The swash plate 14 can be displaced by means of the motorized drive or steering gear 13.

[0043] By using a motorized drive 13 for the swash plate 14, it is possible to precisely, sensitively, and reproducibly control the steering wires 12 for pivoting the distal pivoting elements 11 or the tool tip 6. Furthermore, the number of steering wires 12 to be used for a motorized drive 13 can be freely selected.

[0044] The steering gear 13 has, as shown in Fig. 2 bis 9 can be seen, two drives with motors 17, 17' (in Fig. 9 not shown) with parallel drive axes C, C', which also run parallel to a common axis of rotation A of the two drive wheels 18, 19, between which the spatially adjustable swash plate 14 is arranged.

[0045] Fig. 2 and 3 show an example of a first embodiment of the steering gear 13 according to the invention for a surgical instrument 1, which as in Fig. 1 shown, is arranged at the proximal end 3 of the shaft 2, which defines the longitudinal or main axis B and has the angling mechanism 9 at the distal end 5. The drives of the steering gear 13 have a first drive wheel 18 driven by the first motor 17 and a second drive wheel 19 driven by the second motor 17', between which the swash plate 14 is arranged. The two drive wheels 18, 19 lie on a common axis of rotation A and are both designed as double wheels 18, 19, so that they each have a bevel gear ring 18.2, 19.2 and a drive ring 18.1, 19.1. The double wheels 18, 19 can preferably be manufactured in one piece. Alternatively, it is also possible for each double wheel to consist of a bevel gear and a wheel with a drive ring connected to it.

[0046] The bevel gear rings 18.2, 19.2 of the double wheels 18, 19 face each other and mesh with a third gear 25 and a fourth gear 31 arranged opposite thereto, which are coupled to the swash plate 14 and lie on an axis of rotation D which is at a right angle to the common axis A of the double wheels 18, 19.

[0047] To transmit the actuating movements of the motors 17, 17' to the drive wheels 18, 19, the steering gear 13 has a first pinion 16a, which is driven by the first motor 17 via a first drive shaft 15a and meshes with the drive ring 18.1 of the first double wheel 18. Similarly, the second pinion 16b, which meshes with the drive ring 19.1 of the second double wheel 19, is driven by the second motor 17' via a second drive shaft 15b. The drive shafts 15a and 15b define the first and second drive axes C and C', which run not only parallel to each other but also parallel to the common axis of rotation A of the two drive wheels 18, 19.

[0048] With this arrangement, the two driven double wheels 18, 19 of the steering gear 13 can be arranged with respect to the swash plate 14 such that the two drive axes C, C' and the common axis of rotation A of the two double wheels 18, 19 run perpendicular, i.e. at a right angle to the longitudinal axis B of the surgical instrument 1. In this way, the drive axes C, C' can be positioned relatively close to the longitudinal axis B. Since the steering gear 13 means that the motors 17, 17' do not have to be installed opposite one another in order to move the two drive wheels 18, 19, the overall height of the instrument can be reduced by arranging both motors 17, 17' next to one another on one side with respect to the longitudinal axis B.

[0049] The positioning of the drive axles C, C' on a circular path UC around the drive wheels 18, 19 can be selected almost arbitrarily, as in Fig. 4-6 is indicated, provided that the installation space there is not occupied by other instrument components such as main shaft 21, steering wires 12, fan washer 22 or actuating element 8. The Fig. 4-6 The variants shown show arrangements of the drive units comprising pinions 16a, 16b, drive shafts 15a, 15b and motors 17, 17' as close as possible to the longitudinal axis B, which is preferred for reasons of saving installation space. However, an arrangement of the drive units at any point on the circular path UC is also conceivable, as long as the pinions 16a, 16b mesh with the drive rings 18.1, 19.1. The diameter of the circular path UC depends on the diameter of the drive wheels 18, 19 and the diameter of the pinions 16a, 16b or the toothing. By changing the transmission ratio, a changed circular path diameter can therefore result, which determines the possible positioning of the drive axes C, C'.

[0050] In Fig. 7 und 8 an example of an alternative embodiment of the steering gear 13 is shown, in which the two drive axes C, C', which are defined by the drive units comprising motor 17, 17', drive shaft 15a, 15b, and pinion 16a, 16b, run parallel to the longitudinal axis B of the surgical instrument 1. This is made possible by the fact that the double wheels driven by the drive units are designed as hollow double wheels 18', 19', and can therefore be arranged in the steering gear 13 in relation to the swash plate 14 in such a way that the common axis of rotation A of the two hollow double wheels 18', 19' is aligned with the longitudinal axis B of the surgical instrument 1. By hollowing out the double wheels 18', 19', the instrument components leading to the swash plate 14, such as, for example, B. Main shaft 21 and steering wires 12 are passed through the double wheels 18', 19'.This also enables a space-saving, longitudinal axis-close positioning of the drive units, whereby here too a positioning of the drive axles C, C' on a circular path around the double wheels 18', 19' (corresponding to UC in . Fig. 4 ) can basically be chosen arbitrarily.

[0051] In the Fig. 2 bis 8 In the examples shown, the drive rings 18.1, 19.1 of the double wheels 18, 19 or hollow double wheels 18', 19' are designed as toothed rings and the pinions 16a, 16b are correspondingly designed as gear wheels which engage or mesh with the drive rings 18.1, 19.1 designed as toothed rings. Fig. 9 shows an example of a further alternative embodiment of the steering gear 13 with a belt drive for transmitting the actuating movement of the motor 17, 17' to the respective drive wheel 18, 19.

[0052] In Fig. 9 The motors are not shown for the sake of clarity, but it goes without saying that the pinions 16a, 16b shown, designed as pulleys, are driven by a respective motor with a respective drive shaft located on the drive axles C, C'. The drive rings 18.1, 19.1 of the double wheels 18, 19 are also designed as pulleys, so that an adjusting movement can be transmitted from the first pinion 16a via a first drive belt 44 to the first drive wheel 18, and correspondingly an adjusting movement from the second pinion 16b via a second drive belt 45 to the second drive wheel 19.

[0053] As in Fig. 9 As can be seen from the drive ring 18.1, which has teeth, in this example the belt 44 is designed as a toothed belt. Consequently, the pinion 16a, designed as a pulley, also has teeth. The same applies to the second drive unit, i.e., pinion 16b, belt 45, and drive ring 19.1, even if this is not apparent in the figure.

[0054] Of course, belt drives other than a toothed belt drive, such as flat belts, round belts, V-belts or V-ribbed belts, can also be used, whereby the pulleys are designed with a circumferential profile corresponding to the drive belt. Fig. 9 In the example shown with belt drive, an embodiment with a chain drive is also conceivable (not shown figuratively), in which instead of the Fig. 9 shown belts 44, 45 chains are used and accordingly the pinions 16a, 16b and the drive rings 18.1, 19.1 are designed as chain wheels In the versions with drive belts or corresponding drive chains, the positioning of the pinions 16a, 16b or the drive axes C, C' can be selected not only independently of one another and arbitrarily on a circular path around the drive wheels 18, 19, but by varying the length of the drive belt or the chain, they can also be selected at any distance from the drive wheels 18, 19. However, since a reduction in installation space is desirable, positioning of the drive axes C, C' close to the drive wheels 18, 19, and preferably also close to the longitudinal axis B is preferred.

[0055] The structure of the spatially adjustable disc 14 and its mounting described below are identical for all embodiments of the motorized drive or steering gear 13. The structure and operation of the steering gear 13 and in particular of the swash plate 14 actuated via the drive units are described below with reference to Fig. 3 , 8 , 9 and in particular Fig. 10 described in which, for reasons of better clarity, only the bevel gears with the bevel gear rings 18.2, 19.2 of the drive wheels 18, 19 are shown.

[0056] As can be seen from the figures, a hollow main shaft 21 extending coaxially to the longitudinal axis B of the shaft 2 is arranged in the shaft 2, which is rotatable about the longitudinal axis B of the shaft 2 and extends beyond the proximal end 3 of the shaft 2 into the area of ​​the steering gear 13. The actuating element 8 for actuating the instrument 7 is mounted axially displaceably within this hollow main shaft 21.

[0057] The steering wires 12 emerging from the shaft 2 at the proximal end 3 of the shaft 2, for which a shaft end piece 3 can be provided at the proximal shaft end, in which through slots for the steering wires 12 are provided, are fanned out in the example shown via a fan disk 22 arranged on the shaft end piece 3 in a rotationally fixed manner with respect to the main shaft 21, whereby the radial distance of the steering wires 12 from the longitudinal axis B of the shaft 2 is increased. While the diameter of the bundle of steering wires 12 coaxially surrounding the longitudinal axis B of the shaft 2 within the shaft 2 or at the distal end 5 in the area of ​​the angulation mechanism 9 is, for example, 4 mm, the diameter of the bundle formed by the steering wires 12 behind the fan disk 22 is, for example, 18 mm.By increasing the radial distance of the steering wires 12 from the longitudinal axis B of the shaft 2 with the aid of the fan washer 22, not only is the assembly and manufacture of the gear 13 equipped with the swash plate 14 simplified, but the necessary adjustment angle of the swash plate 14 is also proportionally reduced in order to achieve a desired high pivot angle of the tool tip 6. With this exemplary enlargement of the diameter of the steering wire bundle from 4 mm inside the shaft 2 to 18 mm behind the fan washer 22, the adjustment angle of the swash plate 14 is correspondingly reduced by 4.5 times compared to the pivot angle of the tool tip 6 that can be achieved at the distal end. In order to angle this by 90°, the swash plate 14 only needs to be pivoted by 20°.

[0058] On the proximal side, behind the fan-shaped disk 22, the steering wires 12, which run parallel to the longitudinal axis B of the shaft 2, are fed to the swashplate 14. To secure the steering wires 12 to the swashplate 14, through-holes 23 are formed in the swashplate 14 for each steering wire 12. In the example shown, the steering wires 12 are non-positively connected and fixed to the swashplate 14 within the through-holes 23 via grub screws 24. Alternative methods of fastening the steering wires to the swashplate include, for example, welding, crimping, or other clamping devices.

[0059] The drive wheels 18 and 19 are coupled to a third gear 25, which is preferably designed as a bevel gear and meshes with the two bevel gear rims 18.2, 19.2 of the double wheels 18 and 19, so that the axis of rotation D of the third gear 25 intersects the common axis of rotation A of the drive wheels 18 and 19 and the longitudinal axis B of the shaft 2. Through the three meshing gears 18, 19, and 25, every movement of the two drive wheels 18 and 19 is transmitted directly to the swash plate 14 coupled to the third gear 25, which causes direct actuation of the steering wires 12.

[0060] To form a cardanic bearing of the swash plate 14 on the main shaft 21, the swash plate 14 is pivotably mounted on a universal joint disc 28 via two bearing pins 27 arranged offset by 180° to each other, which in turn is pivotably mounted on the main shaft 21 via two bearing pins 29 arranged offset by 180° to each other. Fig. 10 Due to the partial sectional view, only one bearing pin 27 and one bearing pin 29 can be seen.

[0061] The bearing pins 27 of the swash plate 14 and the bearing pins 29 of the universal joint disc 28 are arranged offset by 90° from each other. This bearing arrangement enables the swash plate 14 to pivot about two axes perpendicular to each other relative to the longitudinal axis B of the shaft 2 and to transmit a rotation of the main shaft 21 about the longitudinal axis B to the swash plate 14, whereby the tool tip 6 can be pivoted in all spatial directions relative to the longitudinal axis B of the shaft 2 via the steering wires 12 on the distal side.

[0062] An alternative cardanic mounting of the swash plate 14 on the main shaft 21 (not shown) provides that the main shaft 21, in the area provided for mounting the swash plate 14, has two guide grooves extending along the main shaft 21 and introduced on both sides or diametrically into the main shaft 21, into which two pins arranged diametrically and radially inwardly on the swash plate 14 engage. As a result of this engagement, the swash plate 14 can be pivoted from a neutral position, in which the swash plate 14 lies in a plane defined by the axis of rotation A perpendicular, i.e. at right angles, to the longitudinal axis B, both about the axis of rotation D and about the axis of rotation A. Superimposed movements by pivoting about both axes of rotation A, D are also possible.Furthermore, the engagement of the pins 29 in the guide grooves 20a allows the transmission of a rotation angle of the main shaft 21 to the swash plate 14, so that the swash plate 14 can be displaced three-dimensionally relative to the longitudinal axis B of the shaft 2. The maximum tilting or twisting or the maximum tilting and rotation angles about the rotation axes A and D are determined by the length and depth of the guide grooves 20a in interaction with the inner diameter and thickness of the swash plate 14 and the length of the pins 29. In the example shown, the main shaft 21 has a spherical section 20b in the area provided for supporting the swash plate 14, on which the guide grooves 20a are present and which fixes the swash plate 14 in the axial direction. The swash plate 14 has a receiving recess contoured to fit the spherical section 20b.

[0063] As continues from Fig. 3 , 8 , 9 and 10As can be seen, the spatially adjustable disc 14 is mounted in a steering ring 30 which is non-rotatably coupled to the third gear 25.

[0064] In order to close the toothed chain formed by the drive wheels 18, 19 and gear 25 into a closed toothed ring, which ensures a uniform circumferential power distribution, a fourth gear 31 is arranged on the axis of rotation D of the third gear 25 opposite the third gear 25, which fourth gear is also preferably designed as a bevel gear and is in engagement with the bevel gear rings 18.2, 19.2 of the two double wheels 18 and 19.

[0065] The swash plate 14 is mounted via a bearing ring 32 in the steering ring 30, which is non-rotatably coupled to the third gear 25, to enable rotation of the swash plate 14 about the longitudinal axis B of the shaft 2. The steering ring 30, which is non-rotatably coupled to the third gear 25, is freely rotatable with respect to the fourth gear 31 by means of a bearing ring 42, so that rotation of the fourth gear 31 about its rotational axis D does not cause any rotation of the steering ring 30 and the swash plate 14.

[0066] The described cardanic mounting of the swash plate 14 on the main shaft 21 enables the swash plate 14 to be displaced three-dimensionally relative to the longitudinal axis B of the shaft 2. If, starting from the Fig. 10 shown neutral starting position, in which the swash plate 14 is aligned perpendicular to the longitudinal axis B of the shaft 2, the drive wheels 18 and 19 via the motors 17, 17' (cf. Fig. 2-8 ) are driven so that the drive wheels 18 and 19 rotate in the same direction, this rotation of the drive wheels 18 and 19, due to the meshing engagement with the third gear 25 and the fourth gear 31, causes the structural unit formed from the third gear 25, the swash plate 14 coupled to the third gear 25 and the fourth gear 31 to tilt about the common axis of rotation A of the drive wheels 18 and 19. To simplify the functional description, the alignment of the bearing pins 27, 29 of the cardanic bearing with respect to the axes of rotation A and D is referred to below. In fact, upon rotation of the main shaft 21 and thus of the swash plate 14, the bearing pins 27, 29 are no longer aligned with the axes A and D as shown, so that the pivot axes of the swash plate 14 provided by the bearing pins 27, 29 may deviate from the rotation axes A, D of the steering gear 13.

[0067] The bearing pins 27, which are aligned with the axis of rotation A of the drive wheels 18 and 19 and via which the swash plate 14 is pivotably mounted on the universal joint disc 28, enable this tilting of the swash plate 14 relative to the main shaft 21. This tilting of the swash plate 14 about the axis of rotation A relative to the longitudinal axis B of the shaft 2 causes, via the steering wires 12, that the tool tip 6 is pivoted on the distal side in a corresponding manner relative to the longitudinal axis B of the shaft 2.

[0068] If, starting from the Fig. 10 In the neutral starting position shown, in which the swash plate 14 is aligned perpendicular to the longitudinal axis B of the shaft 2, the drive wheels 18 and 19 are driven by the motors 17, 17' so that the drive wheels 18 and 19 rotate in opposite directions, this rotation of the drive wheels 18 and 19, due to the meshing engagement with the third gear 25, causes the structural unit formed from the third gear 25 and the swash plate 14 coupled to the third gear 25 to rotate about the rotational axis D of the third gear 25.

[0069] The bearing pins 29, which are aligned with the axis of rotation D of the third gear 25 and via which the universal joint disc 28 is pivotally mounted on the main shaft 21, together with the free rotation of the swash plate 14 relative to the fourth gear 31 due to the bearing ring 32, enable this rotation of the universal joint disc 28 relative to the main shaft 21. This rotation of the swash plate 14 about the axis of rotation D relative to the longitudinal axis B of the shaft 2 causes, via the steering wires 12, the tool tip 6 to be pivoted on the distal side in a corresponding manner relative to the longitudinal axis B of the shaft 2.

[0070] Furthermore, it is of course possible to superimpose the described movements so that, for example, the swash plate 14 is tilted about the common axis of rotation A of the drive wheels 18, 19 and simultaneously rotated about the axis of rotation D of the third gear 25. By combining the two movement sequences due to the individually controllable motors 17, 17' of the gear 13 and the coupling to the main shaft 21, the swash plate 14 can be adjusted three-dimensionally relative to the longitudinal axis B of the shaft 2, which results in a corresponding spatial displacement of the tool tip 6 due to the coupling via the steering wires 12.

[0071] A surgical instrument 1 designed as described above is characterized in that many thin steering wires 12 can be used to control the pivotable tool tip 6, and this control is carried out sensitively, precisely and reproducibly due to the motorized drive 13 for the swash plate 14 on which the steering wires 12 are mounted.

[0072] An exemplary embodiment of the invention is illustrated in the drawings. The drawings, the description, and the claims contain numerous features in combination. Those skilled in the art will expediently consider the features individually and combine them into further useful combinations. The present invention provides a steering gear 13 for a surgical instrument 1, which can be arranged at the proximal end 3 of a shaft 2, which defines a longitudinal axis B and has an angling mechanism 9 at the distal end 5. The steering gear 13 has two motorized drives and is designed to spatially align a swash plate 14 via the setting angles of the two drives. The two drives each have a drive wheel 18, 18', 19, 19' driven by motors 17, 17', which is designed as a double wheel 18, 18', 19, 19' with a bevel gear ring 18.2, 19.2 and a drive ring 18.1, 19.1.The swash plate 14 is arranged between the two drive wheels 18, 19; 18', 19', which have a common axis of rotation A, and the bevel gear rings 18.2, 19.2 face one another, wherein the drive rings 18.1, 19.1 of both double wheels 18, 19; 18', 19' are each operatively connected to a pinion 16a, 16b. The pinions 16a, 16b, which are each operatively connected to one of the drive rings 18.1, 19.1, can be driven by the respective motor 17, 17' via a respective drive shaft 15a, 15b, which defines a drive axis C, C', wherein the two drive axes C, C' are parallel to one another and parallel to the common axis of rotation A of the two drive wheels 18, 19; 18', 19'. Furthermore, a surgical instrument 1 is disclosed which has such a steering gear 13. Bezugszeichenliste

[0073] 1Medical instrument 2Shaft 3Proximal end (shaft) / end piece 4Actuating unit 5Distal end (shaft) 6Instrument tip 7Instrument 8Actuating element 9Joint mechanism 11Pivoting link 12Steering wire 13Steering gear 14Disk (spatially adjustable) 15a,bDrive shaft 16a,bPinion 17, 17'Motor 18, 18'Drive wheel, hollow drive wheel 18.1, 18.2Drive ring, bevel gear 19, 19'Drive wheel, hollow drive wheel 19.1, 19.2Drive ring, bevel gear 21Main shaft 22Fan washer 23Through hole 24Set screw 25Third gear 27Bearing pin 28Universal joint disc 29Bearing pin 30Steering ring 31Fourth gear 32Bearing ring 42Bearing ring 44, 45Drive belt AGommon rotation axis drive wheels BLongitudinal axis C, C'Drive axis DRotation axis third gear UC Circular path

Claims

1. A steering gear (13) for a surgical instrument (1) which can be arranged at the proximal end (3) of a shaft (2), which defines a longitudinal axis (B) and has a bending mechanism (9) at the distal end (5), wherein the steering gear (13) has two motorised drives and a swash plate (14), and is designed to spatially align the swash plate (14) via the adjustment angles of the two drives, which swash plate is designed to control the distal bending mechanism (9) of the surgical instrument (1), wherein the first drive has a first drive wheel (18, 18') which is driven by a first motor (17) and is designed as a double wheel (18, 18') with a first bevel gear rim (18.2) and a first drive rim (18.1), and the second drive has a second drive wheel (19, 19') which is driven by a second motor (17') and is designed as a double wheel (19, 19') with a second bevel gear rim (19.2) and a second drive rim (19.1), wherein the swash plate (14) is arranged between the two drive wheels (18, 19; 18', 19'), which have a common axis of rotation (A), and the bevel gear rims (18.2, 19.2) face one another, and wherein the drive rims (18.1, 19.1) of both double wheels (18, 19; 18', 19') are each operatively connected to a pinion (16a, 16b), wherein a first pinion (16a), which is operatively connected to the first drive rim (18.1), can be driven by the first motor (17) via a first drive shaft (15a), which defines a first drive axis (C), and a second pinion (16b), which is operatively connected to the second drive rim (19.1), can be driven by the second motor (17') via a second drive shaft (15b), which defines a second drive axis (C'), and wherein the two drive axes (C, C') run parallel to each other and parallel to the common axis of rotation (A) of the two drive wheels (18, 19; 18', 19').

2. The steering gear (13) according to claim 1, characterised in that the two double wheels (18, 19) of the steering gear (13) are arranged in relation to the swash plate (14) in such manner that the two drive axes (C, C') and the common axis of rotation (A) of the two double wheels (18, 19) run perpendicular to the longitudinal axis (B) of the surgical instrument (1), wherein the motors (17, 17') are preferably arranged next to each other on one side in relation to the longitudinal axis (B).

3. The steering gear (13) according to claim 1, characterised in that the first drive wheel (18, 18') is designed as a hollow double wheel (18') and the second drive wheel (19, 19') is designed as a hollow double wheel (19'), and the two hollow double wheels (18', 19') of the steering gear (13) are arranged in relation to the swash plate (14) in such manner that the common axis of rotation (A) of the two hollow double wheels (18', 19') is aligned with the longitudinal axis (B) of the surgical instrument (1) and the two drive axes (C, C') run parallel to the longitudinal axis (B) of the surgical instrument (1).

4. The steering gear (13) according to one of claims 1 to 3, characterised in that the drive rims (18.1, 19.1) are gear rims, and the pinions (16a, 16b) are gear wheels which engage with the drive rims (18.1, 19.1) designed as gear rims.

5. The steering gear (13) according to one of claims 1 to 3, characterised in that the drive rims (18.1, 19.1) and the pinions (16a, 16b) - are designed as belt pulleys with a circumferential profile for a drive belt (44, 45), wherein a first drive belt (44) provides the operative connection between the first drive rim (18.1) and the first pinion (16a), and a second drive belt (45) provides the operative connection between the second drive rim (19.1) and the second pinion (16b), or - are designed as sprockets for a drive chain, wherein a first drive chain provides the operative connection between the first drive rim (18.1) and the first pinion (16a), and a second drive chain provides the operative connection between the second drive rim (19.1) and the second pinion (16b).

6. The steering gear (13) according to claim 5, characterised in that each drive belt (44, 45) is a flat, round, V-, V-ribbed or toothed belt, and the circumferential profile of the drive rims (18.1, 19.1) and the pinions (16a, 16b) is correspondingly a flat, round, V-, V-ribbed or toothed profile.

7. The steering gear (13) according to one of claims 1 to 6, characterised in that the swash plate (14) is coupled to a third gear wheel (25), which is in engagement with the two bevel gear rims (18.2, 19.2) of the two double wheels (18, 19; 18', 19') and whose axis of rotation (D) is at a right angle to the common axis of rotation (A) of the driven double wheels (18, 19; 18', 19'), wherein the swash plate (14) is preferably coupled to a fourth gear wheel (31) which is coupled to the two bevel gear rims (18.2, 19.2) of the two double wheels (18, 19; 18', 19') and is arranged on the side facing away from the third gear wheel (25).

8. A surgical instrument (1) having a shaft (2), an actuation unit (4) arranged at the proximal end (3) of the shaft (2) and an instrument (7) arranged at the distal end (5) of the shaft (2) with a tool tip (6) which can be angled by means of a distal bending mechanism (9) and which can be controlled by a swash plate (14) which can be spatially aligned by means of two drives, characterised in that the surgical instrument (1) has a steering gear (13) according to at least one of claims 1 to 7, which has the two drives and is designed to transfer the adjustment angles of the two drives to the spatial orientation of the swash plate (14).

9. The surgical instrument (1) according to claim 8, characterised in that the swash plate (14), for coupling with a third gear wheel (25), which is in engagement with the two bevel gear rims (18.2, 19.2) of the two double wheels (18, 19; 18', 19'), is mounted rotatably about the longitudinal axis (B) of the shaft (2) via a bearing ring (32) in a steering ring (30), which is coupled to the third gear wheel (25) in a rotationally-fixed manner, wherein the swash plate (14) is coupled in a cardanic manner to a main shaft (21) running coaxially to a longitudinal axis (B) of the shaft (2).

10. The surgical instrument (1) according to claim 9, characterised in that the swash plate (14) is pivotably mounted on a universal joint disc (28) via two bearing pins (27) arranged offset by 180° relative to one another, wherein the universal joint disc (28) is pivotably mounted on the main shaft (21) via two bearing pins (29) arranged offset by 180° relative to one another and wherein the bearing pins (27, 29) of the swash plate (14) and the universal joint disc (28) are arranged offset by 90° relative to one another, or the cardanic mounting is provided by two longitudinally extending guide grooves located diametrically in the main shaft (21) and two pins arranged diametrically and pointing radially inwards on the swash plate (14), wherein each pin engages in one of the guide grooves such that an angle of rotation of the main shaft (21) can be transmitted to the swash plate (14).

11. The surgical instrument (1) according to at least one of claims 8 to 10, characterised in that steering wires (12) run in the longitudinal direction (B) of the shaft (2) and are connected to the swash plate (14) of the steering gear (13).

12. The surgical instrument (1) according to claim 11, characterised in that the fourth gear wheel (31) is coupled to the swash plate (14) via a bearing ring (42) with the steering ring (30), wherein the fourth gear wheel (31) is freely rotatable relative to the third gear wheel (25).

13. The surgical instrument (1) according to at least one of claims 11 or 12, characterised in that an actuating element (8) is mounted so as to be axially displaceable in the shaft (2) and is operatively connected to the actuation unit (4) at the proximal side, and in that the distal bending mechanism (9) of the bendable tool tip (6) consists of swivel members (11) which are arranged at the distal end (5) of the shaft (2) and which are connected to the steering gear (13) via steering wires (12) running in the longitudinal direction (B) of the shaft (2).

14. The surgical instrument (1) according to at least one of claims 11 to 13, characterised in that a radial distance of the steering wires (12) from the longitudinal axis (B) of the shaft (2) is greater at the swash plate (14) than at the proximal end (3) of the shaft (2) from which the steering wires (12) emerge, wherein - the steering wires (12) extend from the proximal end (3) of the shaft (2) directly to the swash plate (14), wherein the steering wires (12) run at an angle to the swash plate (14) that deviates from 90°, or - on the distal side in front of the swash plate (14) is arranged a serrated lock washer (22) on the main shaft (21), which increases the radial distance of the steering wires (12) from the longitudinal axis (B) of the shaft (2) such that the steering wires (12) run parallel to each other between the serrated lock washer (22) and the swash plate (14) and form an angle of 90° in relation to a plate surface of the swash plate (14).