Shaft of a manual medical instrument or a shaft for a manual medical instrument

Abstract

The present disclosure relates to a shaft (1) for / with a manual medical instrument (42), preferably a minimally invasive surgical instrument, comprising a proximal shaft portion (2), a distal shaft portion (4) that is tilted in the course of rotation relative to the proximal shaft portion (2), and a gear set (7) disposed within the shaft (1) for transmitting rotational motion from the proximal shaft portion (2) to the distal shaft portion (4). The gear set (7) comprises a tubular transmission element (18) for transmitting rotational motion to the distal shaft portion (4). The transmission component / element (18) is a tubular piece having two axially spaced apart connection portions and a central bend portion in which a number of recesses (32) are formed, the recesses being spaced apart both circumferentially and in the longitudinal direction of the tube, being generally oval / elliptical, extending circumferentially, having tapered recess ends, and being disposed relative to one another such that an oblique recess pattern is generated when the central bend portion is unfolded in a plane.

Description

[Technical field]

[0001] TECHNICAL FIELD The present disclosure relates to shafts of or for medical hand instruments and medical hand instruments. [Background technology]

[0002] From the prior art, angled shafts for medical hand instruments are known. Medical hand instruments of this type are for example drills and milling cutters used in minimally invasive surgery. They usually have a handle to which the instrument shaft is attached or can be attached, as the subject of the present disclosure. A drive or power system is housed within the shaft, which transmits torque from a drive / motor unit, preferably in the handle, to an effector (milling cutter, drill) at the distal end of the shaft.

[0003] In surgical procedures, the space available and ease of handling of instruments play an important role: especially the part of the instrument shaft where the distal effector is located should be as space-saving as possible and actively bendable (intentionally implemented by the actuation mechanism).

[0004] To this end, an exemplary shaft has a distal shaft portion and a proximal shaft portion. The distal shaft portion is rotatable about its longitudinal axis relative to the proximal shaft portion. Because the opposing support surfaces of the two shaft portions are inclined / tilted in the same manner at a non-90° angle relative to the longitudinal axis of the shaft, rotating the distal shaft portion causes the distal shaft portion to be tilted or straightened relative to the proximal shaft portion. In this manner, the shaft of the medical hand instrument, and therefore the effector, can be tilted relative to the handle when the hand instrument is in use.

[0005] In order to tilt the distal shaft part relative to the proximal shaft part by rotating the distal shaft part, the rotary motion or rotation needs to be transmitted from the proximal shaft part to the distal shaft part. For this purpose, a gear train is provided in the shaft, which is rotatably mounted on the proximal shaft part and non-rotatably mounted on the distal shaft part. Therefore, when the shaft is tilted, the torque needs to be transmitted to the distal shaft part via a suitable shaft rotation mechanism of the gear train, which must also be bendable / tiltable. Therefore, the shaft rotation mechanism requires a component or structure with the necessary torsional stiffness in the part of the shaft that is simultaneously bendable / deflectable. Furthermore, the circumference of the shaft should be as small as possible, and the shaft should be able to rotate, i.e. tilt, the distal shaft part as accurately as possible. Also, there needs to be enough space inside the shaft for the drive system of the effector itself.

[0006] The applicant's internal prior art proposes a flexible spring plate, which has a sphere at one end of the plate as the aforementioned component or structure. The flexible spring plate connects a proximal shaft portion and a distal shaft portion, which are configured to rotate relative to each other. The sphere is inserted into a groove in one of the shaft portions so as to be axially movable and to transmit rotation. The end of the spring plate opposite the sphere is rigidly connected to the other shaft portion. When one shaft portion rotates, the spring plate transmits the rotation. However, the spring plate can also be bent so as to tilt / twist with respect to the proximal shaft portion together with the distal shaft portion.

[0007] However, it was found that this structure was not capable of transmitting the required torque to the distal shaft. Other embodiments were proposed, but for various reasons, none of them were suitable as a shaft rotation mechanism between the distal and proximal shafts. For example, flexible silicone tubing was considered, but it was not capable of transmitting the required torque from the gear train in the proximal shaft to the distal shaft. Metal tubes with bellows and labyrinth recesses were also proposed. However, none of the embodiments proved to be flexible enough to achieve angular deflections with very low resistance. Summary of the Invention [Problem to be solved by the invention]

[0008] In view of these problems, it is an object of the present disclosure to provide an instrument shaft for a medical hand instrument that is tiltable according to the aforementioned functional principles, has a small circumference, and transmits rotational motion from the proximal shaft portion to the distal shaft portion reliably and responsively even in the tilted state. Moreover, the tilting motion should be as smooth as possible.

[0009] This object is achieved according to the present disclosure by a shaft for a medical hand instrument having the features of claim 1. This object is further achieved by a medical hand instrument having the features of claim 15. [Means for solving the problem]

[0010] The present disclosure therefore relates to a shaft for / with a medical hand instrument, preferably a minimally invasive surgical instrument, having a proximal shaft portion and a distal shaft portion. The distal shaft portion rotates relative to the proximal shaft portion and is tilted and straight due to end bearing surfaces which are preferably inclined in the same manner relative to the longitudinal direction of the shaft. A gear train with a torque transmission component / element is provided in the shaft, in particular at the tilt mechanism contact area of ​​the distal and proximal shaft portions, the gear train transmitting a rotary motion or rotation from the gear train in the proximal shaft portion to the distal shaft portion. The gear train thus has a tubular transmission component / element which transmits the rotary motion to the distal shaft portion and allows tilting between the two shaft portions. According to the present disclosure, the tubular transmission component / element has a number of slot-like elliptical recesses, each of which has a tip and extends in the circumferential direction of the transmission component / element. Further, the recesses are disposed on a plurality of planes spaced apart along the length of the component, and are circumferentially spaced apart on each plane such that the recesses on two adjacent planes are circumferentially offset from one another.

[0011] In other words, the transmission component / element consists of a tubular piece having two axially spaced connection / end portions and a central bend having a plurality of generally oval / elliptical circumferential slits, the slits having tapered slit ends, spaced apart circumferentially and in the longitudinal direction of the tube, and positioned relative to one another such that an oblique slit pattern is formed when the central bend is unfolded in a plane.

[0012] The distal shaft section is rotatable relative to the proximal shaft section around the longitudinal axis of the shaft. The mutually opposing end faces of the distal shaft section and the proximal shaft section each have an action angle relative to the longitudinal axis of the shaft. When the distal shaft section rotates relative to the proximal shaft section, the distal shaft section is tilted by two (equal) action angles relative to the proximal shaft section. The rotary motion / rotation required to rotate the distal shaft section is generated by a gear train in the proximal shaft section, preferably by an adjustment wheel on the proximal shaft section. The rotation is transmitted to the distal shaft section by the gear train in the proximal shaft section and by a transmission element / component. The transmission element / component is substantially a (flexible) metal tube or metal sleeve with a tubular outer wall. The tubular wall of the metal tube / metal sleeve comprises a plurality of elongated elliptical recesses / cuts / notches / slits. Both ends of the oval / elliptical elongated recesses are tapered. The recesses extend in the circumferential direction of the tubular wall and are arranged adjacent to and spaced apart from one another in both the circumferential and longitudinal directions. The recesses are circumferentially offset from one another such that longitudinally spaced recesses partially (but not completely) intersect / overlap one another in the longitudinal, i.e. circumferential, direction of the elongated recesses. The overlapping recesses form an overlap. The overlap is smaller / shorter than the length of the recesses in the longitudinal direction of the recesses or in the circumferential direction of the tubular wall.

[0013] The shaft according to the present disclosure has the following advantages:

[0014] The recesses form a flexible transmission element, which has the required torsional stiffness due to the high proportion of continuous solid material in the tubular wall, and also has the required flexibility, especially due to the tapered oval / elliptical shape of the circumferential slits. Thanks to the stiffness of the claimed shapes, it is possible to use thin-walled metal or steel tubes, so that the circumference of the transmission element can be reduced. This is advantageous, for example, in terms of the installation space in the shaft for accommodating the power system for the effector. Thanks to the configuration of the recesses, the transmission element has a high torsional stiffness and also a good bending property. The transmission element / component has a high stiffness, since the material is not directly separated in the transmission element / component.

[0015] The oval / elliptical recesses allow the transfer element to be compressed at any angle. The transfer element is therefore flexible in all directions. The overlapping recesses mean that there is no (continuous) central cross piece. This gives the transfer element a spring effect. The elliptical recesses also improve the breaking behaviour of the transfer element. The notch stress is lower in the elliptical recesses than in the sharp edges of the straight recesses.

[0016] Advantageous further embodiments of the present disclosure are the subject matter of the attached dependent claims.

[0017] According to any aspect of the disclosure, the tubular outer wall of the transfer element is notched to allow the transfer element to bend in the longitudinal direction. The transfer element also has torsional stiffness. Bending the distal shaft portion causes the transfer element to bend in an arch in its longitudinal direction. It is therefore advantageous for the transfer element to be bendable about its longitudinal axis. The transfer element also transfers rotation from the gear train to the distal shaft portion. The transfer element therefore transfers torque. It is therefore advantageous for the transfer element to have high torsional stiffness.

[0018] According to a further optional aspect of the present disclosure, the recesses overlap at an overlap portion, the length of which is preferably one third of the length of the recesses, which overlap ensures high torsional stiffness and high flexural properties.

[0019] According to a further optional aspect of the present disclosure, the overlap is located at an end region of the recess, rather than at a region of maximum thickness of the recess, which allows multiple recesses to be placed closer together, improving / improving the bending or flexibility of the transfer element.

[0020] The proximal end of the transmission component / element is preferably rotatably fixed to a bushing connected to a pinion driven by a hollow wheel of the gear train. The bushing drives the transmission component / element and transmits the rotational motion of the gear train to the transmission component / element. This allows torque from the gear train in the proximal shaft section to be transmitted to the transmission component / element via the hollow wheel, the pinion and the bushing. The transmission component / element can then transmit torque from the proximal shaft section to the distal shaft section. In this way, a simple and fault-resistant torque transmission can be provided.

[0021] According to a further optional aspect of the present disclosure, the proximal end of the transfer element is rotatably fixed to a bushing that transfers the rotary motion of the gear train to the transfer element. The tubular transfer element has a distal end and a proximal end. The rotation is then transferred to the distal shaft portion via the transfer element.

[0022] According to a further optional aspect of the disclosure, the proximal end of the transmission element is provided with a plurality of elongated holes or longitudinal slits opening towards the proximal end face, the holes / slits being preferably diametrically opposed and each arranged and configured to receive a nose or locking nose of the bushing protruding radially inward from the circumferential wall of the bushing. The longitudinal slits are arranged and shaped to engage the protruding locking nose with the elongated hole and open at the proximal end, whereby the locking nose can move axially within the elongated hole and is fixed / cannot move radially or rotationally fixed in the circumferential direction. In this way, the rotation of the threaded cable is transmitted to the transmission element and the connection is statically determined.

[0023] According to a further optional aspect of the disclosure, the gear train includes a hollow ring in meshing engagement with a pinion that is offset relative to a central axis of the proximal shaft portion and the pinion is fixedly connected to an axially disposed bushing. The hollow ring is operatively connected to the adjusting ring and is thus driven via the adjusting ring. Thus, rotation of the gear train caused by the adjusting ring is transmitted from the hollow ring to the bushing via the pinion and from the bushing to a transmission element / component that is rotatably fixed to the bushing.

[0024] According to a further optional aspect of the present disclosure, the bushing is connected to the pinion by a press fit, thereby rotationally fixing the bushing and the pinion, and preferably axially fixing the bushing and the pinion.

[0025] According to a further optional aspect of the disclosure, the gear train has an eccentric locking sleeve arranged in the outer tube of the proximal shaft section, and the bushing is rotationally mounted in the eccentric locking sleeve. The eccentric locking sleeve thus has an axially extending eccentric bearing bore, and the bushing is slidably mounted in the bearing bore. Due to the presence of the eccentric locking sleeve, the bushing, and thus the transmission element, is not located exactly in the center of the outer tube of the proximal shaft section. This non-centered arrangement of the bushing and the transmission element allows the power system for the distal effector guided in the tubular transmission element to bend over a long distance, resulting in low bending loads.

[0026] According to a further optional aspect of the disclosure, the distal end of the transfer element / component is fixedly connected to an adjusting bushing, which transfers the rotational movement of the transfer element to a distal shaft section that has or constitutes a shaft tip. The fixed connection of the transfer element to the adjusting bushing causes the rotation of the gear train in the proximal shaft section to be transferred by the transfer element to the distal shaft section. The adjusting bushing preferably has an axially extending, eccentrically arranged pin that is form-fittingly engaged with the distal shaft section and rotates with the adjusting bushing, i.e., rotates the distal shaft section.

[0027] According to a further optional aspect of the present disclosure, the transmission element is welded to an inner surface of the adjusting bush, the welding providing a rotationally fixed connection.

[0028] According to a further optional aspect of the disclosure, when the proximal shaft is in a straight configuration position relative to the distal shaft, the transfer element is tilted 22.5° relative to the proximal shaft. When the distal shaft rotates about the transfer element, the transfer element can be tilted 45° relative to the proximal shaft. This is made possible by bending the transfer element 22.5°.

[0029] According to a further optional aspect of the disclosure, the shaft has a circumference of less than 5.6 mm. This small shaft circumference is achieved by the configuration of the transmission elements. The configuration of the recesses allows for a bendable transmission element with the necessary torsional stiffness and small diameter.

[0030] According to a further optional aspect of the disclosure, the transfer element is formed as a single piece, for example by punching recesses in a diagonal pattern in a flat sheet metal, which is then formed into a tubular transfer element and possibly welded. The single piece construction means that no hinges, connecting links, etc. are required between the individual components of the transfer element, which can reduce assembly costs.

[0031] In other words, a shaft of / for a medical hand instrument, preferably a minimally invasive surgical instrument, comprises a proximal shaft portion, a distal shaft portion that tilts by rotation relative to the proximal shaft portion, and a gear train disposed within the shaft, the gear train transmitting rotational motion of the gear train within the proximal shaft portion to the distal shaft portion, the gear train comprising a tubular transmission component / element transmitting the rotational motion to the distal shaft portion and enabling tilting between both shaft portions, the transmission component / element comprising a tubular piece having two axially spaced apart ends and a central bend, or a tubular piece having a tubular bend. a plurality of generally oval / elliptical recesses having tapered recess ends, spaced apart in the circumferential and longitudinal directions of the tube, extending circumferentially, formed in the central bend, the recesses being arranged relative to one another to define an oblique recess pattern when the central bend is unfolded in a plane;

[0032] The shaft may be designed such that the proximal end of the transmission component / element is provided with a number of longitudinal slits which open at the proximal end and each are provided and configured to receive a latch nose protruding radially from the bushing.

[0033] The shaft may be designed such that the gear train comprises a bush, a hollow wheel and a pinion, the pinion being driven by the hollow wheel.

[0034] The shaft may be designed so that the bushing is connected to the pinion by a press fit.

[0035] The shaft may be designed such that the axially spaced recesses overlap in the circumferential direction of the transmission component / element at an overlap, the length of the overlap being preferably one third of the length of the recesses.

[0036] The shaft may be designed such that the overlap defines the area of ​​maximum thickness of the recess.

[0037] The shaft may be designed such that the proximal shaft portion has an eccentric locking sleeve that is fixedly disposed within an outer tube of the proximal shaft portion, and within the eccentric locking sleeve, a bushing is mounted rotatably and off-center relative to a central axis of the proximal shaft portion.

[0038] The shaft may be designed such that the distal end of the transfer component / element is rigidly connected to an adjustment bushing that transfers the rotational motion of the transfer component / element to the distal shaft section.

[0039] The shaft may be designed so that the transmission component / element is welded to the inside of the adjustment bushing.

[0040] The shaft may be designed such that when the two shaft sections are in a straight configuration position, the transfer component / element is inclined at an angle of 22.5°, with the proximal end of the transfer component / element parallel to the central axis of the proximal shaft section and the distal end of the transfer component / element inclined at an angle of 22.5° relative to the central axis of the distal shaft section.

[0041] The shaft may be designed to have a circumference of less than 5.6 mm.

[0042] The shaft may be designed so that the transmission components / elements are formed as a single piece.

[0043] The objects of the present disclosure are also achieved by a medical hand instrument comprising a shaft and a proximal handpiece according to one of the previous aspects. [Brief description of the drawings]

[0044] [Figure 1] 1 shows a longitudinal cross section of a shaft of a medical handpiece according to the present disclosure. [Diagram 2]FIG. 2 shows an isometric view of a transfer element according to a first embodiment of the present disclosure. [Diagram 3] 1 shows a transmission element according to a first embodiment together with an adjusting bush; [Figure 4] 1 shows a cross section of a shaft according to the present disclosure. [Diagram 5] FIG. 1 shows an isometric view of a bush connected to a pinion. [Figure 6] 1 shows a longitudinal cross section of a straight shaft according to the present disclosure. [Figure 7] 1 shows a longitudinal section of an angled shaft according to the present disclosure. [Figure 8] FIG. 2 shows a top view of a transfer element having multiple recesses in an deployed state according to a first embodiment of the present disclosure. [Figure 9] FIG. 13 shows a side view of a transfer element according to a second embodiment of the present disclosure. [Figure 10] FIG. 13 shows a side view of a transfer element according to a third embodiment of the present disclosure. [Figure 11] FIG. 13 shows a side view of a transfer element according to a fourth embodiment of the present disclosure. [Figure 12] FIG. 13 shows a side view of a transfer element according to a fifth embodiment of the present disclosure. [Figure 13] 1 illustrates a hand instrument according to the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0045] Embodiments of the present disclosure will now be described with reference to the accompanying drawings.

[0046] (First embodiment) FIG. 1 shows a longitudinal section of an (instrument) shaft 1 according to the present disclosure. The shaft 1 has a proximal shaft portion 2 and a distal shaft portion 4. The proximal shaft portion 2 has an outer tube 6. A gear train 7 is disposed within the outer tube 6 of the shaft 1. The gear train 7 has a hollow ring 8, a pinion 10, an eccentric locking sleeve 12, and a bushing 14. The hollow ring 8 is disposed within the outer tube 6 and is driven by an adjustment ring (not shown) that can be operated manually. The hollow ring 8 drives the pinion 10 by meshing the inner gear teeth of the hollow ring 8 with the outer gear teeth of the pinion 10. The pinion 10 is rigidly connected axially (as shown in FIG. 5) to the bushing 14, which is disposed off-center with respect to the central axis of the proximal shaft portion as it is disposed within the eccentric locking sleeve 12. The gear train 7 further has an adjustment bushing 16 and a transmission component / element 18.

[0047] The distal shaft section 4 has a distal shaft tip 20. The adjusting bush 16 has a pin 22 which is arranged offset relative to the central axis of the adjusting bush 16 and extends axially in the distal direction of the adjusting bush 16. The pin 22 is form-fittingly engaged with the proximal end of the distal shaft section 4. The adjusting bush 16 and the distal shaft tip 20 are thus rotationally fixed to one another via the distal shaft section 4. A transmission element 18 axially connects the adjusting bush 16 and the bush 14. The gear train 7, in particular the transmission element 18, thus transmits the rotation from the adjusting wheel (not shown) to the distal shaft section 4. A drive system for an effector 24 (e.g. a milling cutter or drill) attached to the shaft tip 20 is provided inside the proximal shaft section 2 and the distal shaft section 4, and the drive system or power system is partially centrally guided via the gear train 7, in particular via the transmission element 18, the pinion 10 and the hollow wheel 8.

[0048] FIG. 2 shows a transfer element 18 according to a first embodiment. The transfer element 18 is essentially an axially partially flexible tube having a proximal end / proximal end or connection 26 and a distal end / distal end or connection 28. A tube wall 30 of the tubular transfer element 18 has a number / multiple elliptical elongated recesses 32 at a central axial bend 31. The recesses 32 have the shape of a substantially elliptical gap / slit, the ends of the recesses being tapered. The recesses 32 extend longitudinally in the circumferential direction of the tubular transfer element 18, are longitudinally spaced from each of the ends 26, 28 of the transfer element 18 and are offset towards the proximal end / proximal end 26. The recesses 32 are spaced from each other in the longitudinal or axial direction of the transfer element 18 and offset from each other in the circumferential direction of the transfer element, so that an oblique pattern of recesses 32 occurs when the tube wall is inclined in a plane. The configuration of the recesses 32 is described in more detail below.

[0049] The proximal end 26 of the transfer element 18 has two opposing slots / longitudinal slits 34. The longitudinal slits 34 extend longitudinally of the transfer element 18, i.e., the longitudinal slits 34 extend toward but are spaced from the central bend 31 having the recess 32.

[0050] FIG. 3 shows the transfer element 18 connected at its distal end 28 to the adjusting bush 16. The transfer element 18 is preferably welded to the adjusting bush 16. The adjusting bush 16 is substantially a metal ring. The inner diameter of the ring is approximately the same as the diameter of the transfer element 18, and the transfer element 18 is connected to the inside of the ring. A pin 22 is provided on the distal face of the adjusting bush 16. The pin 22 is form-fittingly engaged with the distal shaft section 4. When the transfer element 18 rotates, the adjusting bush 16 also rotates. The pin 22 then co-rotates the distal shaft tip 20 via the distal shaft section 4. In this way, the transfer element 18 transmits the rotation of the gear train 7 in the proximal shaft section 2 to the distal shaft section 4.

[0051] FIG. 4 shows a cross section of the shaft 1. The transmission element 18 is rotationally fixed in the bush 14. The transmission element 18 can move axially. In the radial direction, the radially protruding latch noses 36 of the bush 14 engage in the longitudinal slits 34 of the transmission element 18. The protruding latch noses 36 transmit the rotation of the bush 14 to the transmission element 18. As shown in FIG. 5, the bush 14 is rigidly connected to the pinion 10. The latch noses 36 are opposite each other and protrude radially inwards from the peripheral wall of the bush 14. The bush 14 is connected to the pinion 10, preferably by an interference fit. The bush 14 is mounted in an eccentric lock sleeve 12, which is a spacer sleeve or spacer, in the outer tube 6 of the proximal shaft part 2.

[0052] FIG. 6 shows a longitudinal section of the shaft 1. In this figure, the shaft 1 is straight. It is shown that the proximal end 26 of the transmission element 18 is rigidly connected to the bush 14 and the distal end 28 is rigidly connected inside the adjusting bush 16. This arrangement transmits torque from the pinion 10 through the bush 14 to the transmission element 18, and then to the adjusting bush 16 and the distal shaft part 4. FIG. 7 shows a longitudinal section of the bent shaft 1. In comparison with FIG. 6, it can be seen that the adjusting bush 16 with the pin 22 has been rotated 180° about its longitudinal axis. Thus, the distal shaft tip 20 has also been rotated 180°. Due to the inclined end faces of the outer tube 6 of the distal shaft part 4 and the proximal shaft part 2, the distal shaft part 4 is inclined with respect to the proximal shaft part 2 at the same time as rotating about its longitudinal axis. In this position, the distal shaft portion 4 and the proximal shaft portion 2 are at a 45° angle to each other.

[0053] FIG. 8 shows the sheet / outer tube / covering material 30 of the transfer element 18 laid out in a flat plane. The transfer element 18 has a number of recesses 32. The recesses 32 are elliptical and extend transversely to the longitudinal direction of the transfer element 18, i.e. in the circumferential direction of the tubular transfer element 18. The transfer element 18 has overlapping portions 38, in which the recesses 32 overlap each other in the longitudinal direction, i.e. in the circumferential direction of the tubular transfer element 18. The length of the overlapping portions 38 is smaller than the greater extent of the recesses 32. The length of the overlapping portions 38 is preferably one third of the length of the recesses.

[0054] Modified examples of the shape of the recess 32 will be described below with reference to FIGS.

[0055] Second embodiment Figure 9 shows a side view of a transfer element 18 according to a second embodiment. As can be seen from this figure, the thickness of the recesses in the longitudinal direction of the connection element can be selected such that the material cross-piece between axially spaced recesses is thicker (or thinner). This means that even if the number of slits and the axial spacing of the individual slits are the same, the bending stiffness can be substantially adjusted by selecting the width of the recesses / slits. In Figure 9, the slit width is small, so the cross-piece width between axially adjacent slits is large.

[0056] Third embodiment In contrast to Figure 9, Figure 10 shows a side view of a transfer element 18 according to a third embodiment in which the width of the elliptical recesses 32 is greater in the axial direction of the transfer element (and therefore the central crosspiece is smaller) than in the second embodiment. This reduces notch stresses on either side of the recesses 32. Furthermore, the circumferential length of the recesses 32 is reduced to ensure sufficient wall thickness between circumferentially spaced elliptical recesses 32.

[0057] (Fourth embodiment) FIG. 11 shows a side view of the transfer element 18 according to the fourth embodiment. In the fourth embodiment, the circumferential length of the elliptical recesses 32 is increased. This allows the overlap of the recesses 32 to be increased, making the transfer element 18 flexible. On the other hand, the thickness of the recesses 32 is reduced. This ensures sufficient wall thickness between the individual recesses 32. Therefore, the notch stress is increased. Thus, the fourth embodiment is the exact opposite of the third embodiment.

[0058] Fifth embodiment 12 shows a side view of the transfer element 18 according to the fifth embodiment. The central cross pieces 40 between the recesses 32 all have the same wall thickness. This allows the transfer element 18 to be more flexible without increasing the notch stress.

[0059] The wall thickness of the transfer element 18 is preferably 0.2 mm. The circumference of the transfer element 18 is preferably 2.5 mm. The transfer element 18 is preferably made of steel 1.4301. More preferably, the transfer element 18 is made of a shape memory alloy such as Nitinol, which improves flexibility and dimensional stability. It is also conceivable to make the transfer element 18 from a high-performance steel alloy, such as 1.4197, which increases the torque that can be transferred, for example.

[0060] 13 shows a hand instrument 42 according to the present disclosure comprising a shaft 1 and a handpiece 44. The hand instrument 42 is, for example, a drill or milling cutter. [Explanation of symbols]

[0061] 1: Shaft 2: Proximal shaft 4: Distal shaft section 6:Outer tube 7: Gear train 8:Hollow ring 10: Pinion 12: Eccentric lock sleeve 14: Bush 16: Adjustment bush 18:Transmission elements 20: Distal shaft tip 22: Pin 24: Milling cutter 26: Proximal end of transmission element 28: Distal end of transmission element 30: Outer wall of transmission element 31: Central bend 32: Recess 34: Longitudinal slit 36: Latch nose 38: Overlap 40: Center cross piece 42: Hand instruments 44: Handpiece

Claims

1. A shaft (1) for / with a medical hand instrument (42), preferably a minimally invasive surgical instrument, comprising: a proximal shaft portion (2) and a distal shaft portion (4) that is tilted by rotating relative to the proximal shaft portion (2); a gear train (7) arranged in the shaft (1) for transmitting the rotational motion of the gear train (7) in the proximal shaft portion (2) to the distal shaft portion (4); said gear train (7) comprising a tubular transmission component / element (18) which transmits said rotational motion to said distal shaft portion (4) and allows tilting between both shaft portions (2, 4); said transmission component / element (18) comprises or is a tubular piece having two axially spaced apart ends (26, 28) and a central bend (31); The central bend (31) has a plurality of generally oval / elliptical recesses (32) that have tapered recess ends, are spaced apart in the circumferential direction and in the pipe longitudinal direction, and extend in the circumferential direction; The shaft (1), characterized in that the recesses are arranged relative to one another such that, when the central bend (31) is unfolded in the plane, it results in an oblique recess pattern.

2. the axially spaced recesses (32) overlap in the circumferential direction of the transmission component / element (18) at an overlapping portion (38); 2. The shaft (1) according to claim 1, characterized in that the length of the overlapping portion (38) is preferably one third of the length of the recess (32).

3. 3. The shaft (1) according to claim 2, characterized in that the overlap (38) defines an area of ​​maximum thickness of the recess (32).

4. a proximal end (26) of said transmission component / element (18) being rotationally fixedly connected to a bushing (14); The shaft (1) according to any one of claims 1 to 3, characterized in that the bush (14) transmits the rotational motion from the gear train (7) in the proximal shaft section (2) to the transmission element (18).

5. the proximal end (26) of the transfer component / element (18) is provided with a plurality of longitudinal slits (34); 5. The shaft (1) of claim 4, wherein a plurality of the longitudinal slits (34) are open at the proximal end (26), each of the longitudinal slits (34) being provided and configured to receive a latch nose (36) projecting radially from the bushing (14).

6. The gear train (7) comprises the bush (14), a hollow ring (8), and a pinion (10); The pinion is driven by the hollow wheel (8), 6. The shaft (1) according to claim 4 or 5, characterized in that the bush (14) is fixedly connected axially to the pinion (10).

7. 7. The shaft (1) according to claim 6, characterized in that the bush (14) is connected to the pinion (10) by a press fit.

8. The proximal shaft portion (2) has an eccentric locking sleeve (12) fixedly disposed within an outer tube (6) of the proximal shaft portion (2); The shaft (1) according to any one of claims 4 to 7, characterized in that the bush (14) is rotatably mounted within the eccentric locking sleeve (12) and off-center with respect to the central axis of the proximal shaft portion (2).

9. a distal end (28) of said transmission component / element (18) being rigidly connected to an adjustment bushing (16); The shaft (1) according to one of the preceding claims, characterized in that the adjusting bush (16) transmits the rotational movement of the transmission component / element (18) to the distal shaft portion (4).

10. 10. The shaft (1) according to claim 9, characterized in that the transmission component / element (18) is welded to the inside of the adjusting bush (16).

11. 11. The shaft (1) according to claim 1, characterized in that the transmission component / element (18) is inclined at an angle of 22.5 degrees such that, when the two shaft sections (2, 4) are in a straight configuration position, the proximal end (26) of the transmission component / element (18) is parallel to the central axis of the proximal shaft section (2) and the distal end (28) of the transmission component / element (18) is at an angle of 22.5 degrees relative to the central axis of the distal shaft section (4).

12. A shaft (1) according to one of the claims 1 to 11, characterized in that it has a circumference of less than 5.6 mm.

13. The shaft (1) according to one of the claims 1 to 12, characterized in that the transmission component / element (18) is formed as a single piece.

14. A medical hand instrument (42) comprising a shaft (1) according to one of the claims 1 to 13 and a proximal handpiece (44).

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