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] FIELD OF THE DISCLOSURE The present disclosure relates to shafts of or for medical hand instruments and medical hand instruments. [Background technology]

[0002] Angled shafts for medical hand instruments are known from the prior art. Medical hand instruments of this type are, for example, drills and milling cutters used in minimally invasive surgery. These typically have a handle to which the instrument shaft is attached or attachable, as is 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 for instruments and their ease of handling play an important role. In particular, the part of the instrument shaft where the distal effector is located should be actively bendable (intentionally achieved by the actuation mechanism) while occupying as little space as possible.

[0004] To this end, an exemplary shaft has a distal shaft portion and a proximal shaft portion. The distal shaft portion is rotatable relative to the proximal shaft portion about its longitudinal axis. Because the opposing support surfaces of these two shaft portions are similarly inclined / tilted at a non-90° angle relative to the longitudinal axis of the shaft, rotating the distal shaft portion causes the distal shaft portion to tilt or straighten 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] To tilt the distal shaft portion relative to the proximal shaft portion by rotating the distal shaft portion, rotational motion or rotation must be transmitted from the proximal shaft portion to the distal shaft portion. To achieve this, a gear train is provided within the shaft, which is rotatably mounted on the proximal shaft portion and non-rotatably mounted on the distal shaft portion. Therefore, when the shaft is tilted, torque must be transmitted to the distal shaft portion via an appropriate shaft rotation mechanism within the gear train, which must also be bendable / tiltable. Therefore, the shaft rotation mechanism requires components or structures with the necessary torsional rigidity in the bendable / deflectable portion of the shaft. Furthermore, the shaft should have as small a circumference as possible and be capable of rotating, or tilting, the distal shaft portion as precisely as possible. Sufficient space within the shaft is also required 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 spring plate as a 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 that rotation. However, the spring plate can also bend so as to tilt / twist relative to the proximal shaft portion together with the distal shaft portion.

[0007] However, it was found that this structure was unable to transmit 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 this was unable to transmit the required torque from the gear train in the proximal shaft to the distal shaft. Metal tubing with a corrugated or labyrinth-like recess was also proposed. However, none of these embodiments proved to be flexible enough to achieve angular deflection with very little 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. Furthermore, 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] Accordingly, the present disclosure relates to a shaft for 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 can be tilted or straight due to end bearing surfaces that are preferably inclined in the same manner relative to the longitudinal direction of the shaft. A gear train having a torque transmission component / element is provided within the shaft, particularly at the tilt mechanism contact area of ​​the distal and proximal shaft portions, and the gear train transmits rotary motion or rotation from the gear train within the proximal shaft portion to the distal shaft portion. Thus, the gear train has a tubular transmission component / element that transmits rotary motion to the distal shaft portion and allows tilt between the two shaft portions. According to the present disclosure, the tubular transmission component / element has a plurality of slot-like elliptical recesses, each of which has a distal end and extends circumferentially around the transmission component / element. Furthermore, the recesses are arranged on a plurality of planes spaced apart in the longitudinal direction of the component, and are circumferentially spaced apart on each plane such that the recesses on two adjacent planes are circumferentially offset from each other.

[0011] In other words, the transmission component / element consists of a tubular piece having two axially spaced connecting / 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 longitudinally of the tube, and arranged 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 portion is rotatable relative to the proximal shaft portion around the longitudinal axis of the shaft. The opposing end faces of the distal shaft portion and the proximal shaft portion each have an operating angle relative to the longitudinal axis of the shaft. When the distal shaft portion rotates relative to the proximal shaft portion, the distal shaft portion tilts by two (equal) operating angles relative to the proximal shaft portion. The rotary motion / rotation required to rotate the distal shaft portion is generated by a gear train within the proximal shaft portion, preferably by an adjusting wheel on the proximal shaft portion. The rotation is transmitted to the distal shaft portion by the gear train within the proximal shaft portion and a transmission element / component. The transmission element / component is essentially a (flexible) metal tube or metal sleeve with a tubular outer wall. The tubular wall of the metal tube / metal sleeve has a plurality of elongated elliptical recesses / cuts / notches / slits. Both ends of the oval / elliptical elongated recesses are tapered. The recesses extend circumferentially around the tubular wall and are spaced apart adjacent to each other in both the circumferential and longitudinal directions. The recesses are circumferentially offset from each other such that longitudinally spaced recesses partially (but not completely) intersect / overlap each other in the longitudinal, i.e., circumferential, direction of the elongated recesses. The overlapping recesses form an overlap that is smaller / shorter than the length of the recess in the longitudinal direction of the recess or in the circumferential direction of the tubular wall.

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

[0014] The recesses create a flexible transmission element. The transmission element has the required torsional rigidity due to the high proportion of continuous solid material in the tubular wall, and also the required flexibility, especially due to the tapered oval / elliptical shape of the circumferential slits. Thanks to the rigidity of the claimed shape, it is possible to use thin-walled metal or steel tubes, thereby reducing the outer circumference of the transmission element. This is advantageous, for example, in terms of installation space within a shaft for accommodating the power system for the effector. Thanks to the configuration of the recesses, the transmission element has high torsional rigidity and also excellent flexibility. Since the material is not directly separated in the transmission element / component, the transmission element / component has high rigidity.

[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 crosspiece. This gives the transfer element a spring effect. The elliptical recesses also improve the breaking behavior 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 present disclosure, the outer tubular wall of the transfer element is notched to allow the transfer element to bend longitudinally. The transfer element also has torsional rigidity. Bending the distal shaft causes the transfer element to bend archingly in its longitudinal direction. Therefore, it is advantageous for the transfer element to be bendable about its longitudinal axis. The transfer element also transmits rotation from the gear train to the distal shaft. Thus, the transfer element transmits torque. Therefore, it is advantageous for the transfer element to have high torsional rigidity.

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

[0019] According to a further optional aspect of the present disclosure, the overlapping portions are located in end regions of the recesses rather than in the region of maximum recess thickness, which allows multiple recesses to be positioned closer to each other, improving / enhancing 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, transmitting the rotational motion of the gear train to the transmission component / element. This allows torque from the gear train in the proximal shaft portion to be transmitted to the transmission component / element via the hollow wheel, pinion, and bushing. The transmission component / element can then transmit torque from the proximal shaft portion to the distal shaft portion. In this manner, 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 having a distal end and a proximal end, and the rotation is then transferred to the distal shaft portion via the transfer element.

[0022] According to a further optional aspect of the present disclosure, the proximal end of the transmission element is provided with a plurality of elongated holes or longitudinal slits opening toward the proximal end face, preferably diametrically opposed, each configured and adapted to receive a nose or locking nose of the bushing protruding radially inward from the circumferential wall of the bushing. The longitudinal slits are configured and shaped to allow the protruding locking nose to engage with the elongated holes, and are open at the proximal end. This allows the locking nose to move axially within the elongated holes but be fixed / immovable radially or rotationally fixed in the circumferential direction. In this way, 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 present disclosure, the gear train includes a hollow ring in meshing engagement with a pinion that is offset relative to the central axis of the proximal shaft portion, the pinion being fixedly connected to an axially disposed bushing. The hollow ring is operatively connected to the adjusting ring and is therefore driven through 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 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, which rotationally fixes the bushing and the pinion, and preferably axially fixes them together.

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

[0026] According to a further optional aspect of the present 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 portion having or constituting a shaft tip. The fixed connection of the transfer element to the adjusting bushing allows rotation of the gear train in the proximal shaft portion to be transferred by the transfer element to the distal shaft portion. The adjusting bushing preferably has an axially extending, eccentrically disposed pin that form-fittingly engages the distal shaft portion and rotates with the adjusting bushing, thereby rotating the distal shaft portion.

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

[0028] According to a further optional aspect of the present disclosure, when the proximal shaft is in a straight configuration 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 present disclosure, the shaft has a circumference of less than 5.6 mm. This small shaft circumference is achieved by the configuration of the transfer element. The recess configuration allows for a flexible transfer element with the necessary torsional stiffness and small diameter.

[0030] According to a further optional aspect of the present 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 optionally welded. The single-piece construction means that no hinges, connecting links, etc. are required between the individual components of the transfer element, thereby reducing 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 upon rotation relative to the proximal shaft portion, and a gear train disposed within the shaft that transfers 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 that transfers rotational motion to the distal shaft portion and allows tilting between the 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 end. a plurality of generally oval / elliptical recesses having tapered recess ends, spaced apart in the circumferential direction and in the longitudinal direction of the tube, extending circumferentially; the recesses are arranged relative to one another to form 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 plurality of longitudinal slits, which are 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 so that the gear train comprises a bushing, 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 the overlap, the length of the overlap being preferably one third of the length of the recesses.

[0036] The shaft may be designed so that the overlap defines the maximum thickness area 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 the outer tube of the proximal shaft portion, and within the eccentric locking sleeve, a bushing is mounted rotatably and off-center relative to the central axis of the proximal shaft portion.

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

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

[0040] The shaft may be designed such that when the two shaft sections are in a straight configuration, 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 according to one of the previous aspects and a proximal handpiece. [Brief explanation of the drawings]

[0044] [Figure 1] 1 shows a longitudinal cross section of a shaft of a medical handpiece according to the present disclosure. [Figure 2]1 shows an isometric view of a transfer element according to a first embodiment of the present disclosure; [Figure 3] 1 shows a transmission element according to a first embodiment with an adjusting bushing. [Figure 4] 1 shows a cross section of a shaft according to the present disclosure. [Figure 5] 1 shows an isometric view of a bushing 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 cross section of an angled shaft according to the present disclosure. [Figure 8] FIG. 1 shows a top view of a transfer element having multiple recesses in an unfolded state according to a first embodiment of the present disclosure. [Figure 9] FIG. 10 shows a side view of a transfer element according to a second embodiment of the present disclosure. [Figure 10] FIG. 10 shows a side view of a transfer element according to a third embodiment of the present disclosure. [Figure 11] FIG. 10 shows a side view of a transfer element according to a fourth embodiment of the present disclosure. [Figure 12] FIG. 10 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 INVENTION

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

[0046] (First embodiment) FIG. 1 shows a longitudinal cross section of an (instrument) shaft 1 according to the present disclosure. Shaft 1 has a proximal shaft portion 2 and a distal shaft portion 4. Proximal shaft portion 2 has an outer tube 6. Disposed within outer tube 6 of shaft 1 is a gear train 7. Gear train 7 includes a hollow ring 8, a pinion 10, an eccentric locking sleeve 12, and a bushing 14. Hollow ring 8 is disposed within outer tube 6 and is driven by an adjusting ring (not shown), which may be manually operated. Hollow ring 8 drives pinion 10 by meshing its internal gear teeth with the external gear teeth of pinion 10. Pinion 10 is rigidly connected axially to bushing 14 (as shown in FIG. 5), which is disposed within eccentric locking sleeve 12 and thus off-center relative to the central axis of the proximal shaft portion. Gear train 7 further includes an adjusting bushing 16 and a transmission component / element 18.

[0047] The distal shaft portion 4 has a distal shaft tip 20. The adjusting bushing 16 is disposed off-center relative to the central axis of the adjusting bushing 16 and has a pin 22 extending axially distally of the adjusting bushing 16. The pin 22 is form-fittingly engaged with the proximal end of the distal shaft portion 4. Thus, the adjusting bushing 16 and the distal shaft tip 20 are rotationally fixed to each other via the distal shaft portion 4. A transmission element 18 axially connects the adjusting bushing 16 and the bushing 14. Thus, the gear train 7, and in particular the transmission element 18, transmits rotation from an adjusting wheel (not shown) to the distal shaft portion 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 portion 2 and the distal shaft portion 4, and the drive system or power system is partially centrally guided via the gear train 7, in particular the transmission element 18, the pinion 10, and the hollow wheel 8.

[0048] FIG. 2 illustrates 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 connecting portion 26 and a distal end / distal end or connecting portion 28. The tube wall 30 of the tubular transfer element 18 has numerous / multiple elliptical elongated recesses 32 at a central axial bend 31. The recesses 32 have a generally elliptical gap / slit shape, with the ends tapering. The recesses 32 extend longitudinally around the circumference of the tubular transfer element 18, are longitudinally spaced from each of the ends 26, 28 of the transfer element 18, and are offset toward the proximal end / proximal end 26. The recesses 32 are spaced from one another in the longitudinal or axial direction of the transfer element 18 and offset from one another circumferentially around the transfer element, resulting in a diagonal pattern of recesses 32 when the tube wall is tilted 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 elongated slots / longitudinal slits 34. The longitudinal slits 34 extend longitudinally of the transfer element 18, i.e., they 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 bushing 16. The transfer element 18 is preferably welded to the adjusting bushing 16. The adjusting bushing 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 surface of the adjusting bushing 16. The pin 22 is form-fittingly engaged with the distal shaft portion 4. As the transfer element 18 rotates, the adjusting bushing 16 also rotates. The pin 22 then co-rotates the distal shaft tip 20 via the distal shaft portion 4. In this way, the transfer element 18 transmits the rotation of the gear train 7 in the proximal shaft portion 2 to the distal shaft portion 4.

[0051] FIG. 4 shows a cross section of the shaft 1. The transmission element 18 is rotationally fixed within the bushing 14. The transmission element 18 can move axially. Radially, radially protruding latch noses 36 of the bushing 14 engage with longitudinal slits 34 of the transmission element 18. The protruding latch noses 36 transmit the rotation of the bushing 14 to the transmission element 18. As shown in FIG. 5, the bushing 14 is rigidly connected to the pinion 10. The latch noses 36 face each other and protrude radially inward from the peripheral wall of the bushing 14. The bushing 14 is preferably connected to the pinion 10 by an interference fit. The bushing 14 is mounted within an eccentric locking sleeve 12, which is a spacer sleeve or spacer located within the outer tube 6 of the proximal shaft portion 2.

[0052] FIG. 6 shows a longitudinal cross section of the shaft 1. In this view, the shaft 1 is straight. The proximal end 26 of the transmission element 18 is rigidly connected to the bushing 14, and the distal end 28 is rigidly connected to the inside of the adjusting bushing 16. This configuration allows torque to be transmitted from the pinion 10 through the bushing 14 to the transmission element 18, and then to the adjusting bushing 16 and distal shaft portion 4. FIG. 7 shows a longitudinal cross section of the bent shaft 1. Compared to FIG. 6, it can be seen that the adjusting bushing 16 with the pin 22 has rotated 180° about its longitudinal axis. Therefore, the distal shaft tip 20 has also rotated 180°. Due to the inclined end faces of the outer tube 6 of the distal shaft portion 4 and the proximal shaft portion 2, the distal shaft portion 4 tilts relative to the proximal shaft portion 2 as it rotates 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] 8 shows the sheet / outer tube / covering material 30 of the transfer element 18 laid out flat. The transfer element 18 has a plurality 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, where 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) 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 so that the material cross-pieces between axially spaced recesses are 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 FIG. 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, ensuring sufficient wall thickness between circumferentially spaced elliptical recesses 32.

[0057] (Fourth embodiment) FIG. 11 shows a side view of a transfer element 18 according to a fourth embodiment. In the fourth embodiment, the circumferential length of the elliptical recesses 32 is increased. This allows for greater overlap between the recesses 32, making the transfer element 18 more flexible. Meanwhile, the thickness of the recesses 32 is reduced. This ensures sufficient wall thickness between the individual recesses 32. Therefore, the notch stress is increased. In this way, 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 crosspieces 40 between the recesses 32 all have the same wall thickness, which allows for increased flexibility of the transfer element 18 without increasing 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. It is even more preferred that 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 transmitted.

[0060] 13 shows a hand instrument 42 according to the present disclosure, comprising a shaft 1 and a handpiece 44. The hand instrument 42 may be, for example, a drill or a milling cutter. The items listed below were included in the claims of the original patent application. (Item 1) A shaft (1) for a medical hand instrument (42), preferably a minimally invasive surgical instrument, comprising: a proximal shaft portion (2) and a distal shaft portion (4) that tilts by rotating relative to the proximal shaft portion (2); a gear train (7) disposed within the shaft (1) for transmitting rotational motion of the gear train (7) within the proximal shaft portion (2) to the distal shaft portion (4); the gear train (7) comprises a tubular transmission component / element (18) that transmits the rotational motion to the distal shaft portion (4) and allows tilting between the shaft portions (2, 4); the 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 bent portion (31) has tapered recessed end portions, and a plurality of approximately oval / elliptical recessed portions (32) are formed in the circumferential direction and the pipe longitudinal direction, and extend in the circumferential direction, and the recessed portions (32) are spaced apart in the circumferential direction and the pipe longitudinal direction. The shaft (1) is characterized in that the recesses are arranged relative to one another so as to form an oblique recess pattern when the central bend (31) is unfolded in the plane. (Item 2) the axially spaced recesses (32) overlap in the circumferential direction of the transmission component / element (18) at overlapping portions (38); Item 1. The shaft (1) according to item 1, characterized in that the length of the overlapping portion (38) is preferably one-third of the length of the recess (32). (Item 3) 3. The shaft (1) according to item 2, wherein the overlapping portion (38) defines the area of ​​maximum thickness of the recess (32). (Item 4) a proximal end (26) of the transmission component / element (18) being rotationally fixedly connected to a bushing (14); 4. The shaft (1) according to one of items 1 to 3, characterized in that the bushing (14) transmits the rotational motion from the gear train (7) in the proximal shaft portion (2) to the transmission element (18). (Item 5) the proximal end (26) of the transfer component / element (18) is provided with a plurality of longitudinal slits (34); 5. The shaft (1) according to item 4, wherein the plurality of longitudinal slits (34) are open at the proximal end (26), each being provided and configured to receive a latch nose (36) protruding radially from the bushing (14). (Item 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 item 4 or 5, characterized in that the bush (14) is fixedly connected to the pinion (10) in the axial direction. (Item 7) 7. The shaft (1) according to item 6, wherein the bushing (14) is connected to the pinion (10) by press fitting. (Item 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); 8. The shaft (1) according to one of items 4 to 7, characterized in that the bushing (14) is mounted rotatably within the eccentric locking sleeve (12) and off-center relative to the central axis of the proximal shaft portion (2). (Item 9) The distal end (28) of the transmission component / element (18) is rigidly connected to the adjustment bushing (16); A shaft (1) according to one of items 1 to 8, characterized in that the adjusting bush (16) transmits the rotational movement of the transmission component / element (18) to the distal shaft portion (4). (Item 10) 10. The shaft (1) according to item 9, characterized in that the transmission component / element (18) is welded to the inside of the adjusting bush (16). (Item 11) 11. The shaft (1) according to one of items 1 to 10, characterized in that the transmission component / element (18) is inclined at an angle of 22.5 degrees so that when the two shaft sections (2, 4) are in a straight configuration, 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). (Item 12) A shaft (1) according to one of items 1 to 11, characterized in that the circumference is less than 5.6 mm. (Item 13) 13. The shaft (1) according to one of items 1 to 12, characterized in that the transmission component / element (18) is formed as a single piece. (Item 14) A medical hand instrument (42) comprising a shaft (1) according to one of items 1 to 13 and a proximal handpiece (44). [Explanation of symbols]

[0061] 1: Shaft 2: Proximal shaft 4: Distal shaft 6:Outer tube 7: Gear train 8:Hollow ring 10: Pinion 12: Eccentric lock sleeve 14: Bush 16: Adjustment bush 18: Communication 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: overlapping part 40: Center cross piece 42: Hand instruments 44: Handpiece

Claims

1. 1. A shaft for a medical hand instrument, comprising: a proximal shaft portion and a distal shaft portion that tilts by rotating relative to the proximal shaft portion; 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 includes a tubular transmission component that transmits the rotational motion to the distal shaft portion and allows tilt between the proximal and distal shaft portions; the transmission component is a tubular piece having two axially spaced apart ends and a central bend; the central bend portion is formed with a plurality of oval recesses having tapered recess ends; The recess extends in a circumferential direction of the transmission component, The recesses are spaced apart in the longitudinal direction and the circumferential direction of the transmission component, two recesses adjacent to each other in the longitudinal direction of the transmission component are arranged to be offset from each other in the circumferential direction, shaft.

2. The shaft of claim 1 , wherein the axially spaced recesses overlap in the circumferential direction of the transmission component at overlapping portions.

3. 3. The shaft of claim 2, wherein the length of the overlapping portion is one-third the length of the recess.

4. The shaft of claim 2 , wherein the width of the recess extends in the longitudinal direction, and the width of the overlapping portion of the recess is less than the width of the non-overlapping portion of the recess.

5. a proximal end of the transmission component is rotationally fixedly connected to a bushing; The shaft of claim 1 , wherein the bushing transmits the rotational motion from the gear train in the proximal shaft portion to the transfer component.

6. the proximal end of the transfer component has a plurality of longitudinal slits; 6. The shaft of claim 5, wherein a plurality of the longitudinal slits are open at the proximal end, each positioned and configured to receive a latch nose projecting radially from the bushing.

7. the gear train includes the bushing, a hollow ring, and a pinion; The pinion is driven by the hollow wheel; 6. The shaft of claim 5, wherein the bushing is fixedly connected axially to the pinion.

8. 8. The shaft of claim 7, wherein the bushing is connected to the pinion by a press fit.

9. the proximal shaft portion has an eccentric locking sleeve fixedly disposed within an outer tube of the proximal shaft portion; The shaft of claim 5, wherein the bushing is rotatably mounted within the eccentric locking sleeve and off-center relative to the central axis of the proximal shaft portion.

10. a distal end of the transmission component is rigidly connected to an adjustment bushing; The shaft of claim 1 , wherein the adjustment bushing transmits the rotational movement of the transfer component to the distal shaft portion.

11. 11. The shaft according to claim 10, wherein the transmission component is welded to the inside of the adjusting bush.

12. 2. The shaft of claim 1, wherein the transmission component is angled at a 22.5 degree angle such that when the proximal and distal shafts are in a straight configuration, the proximal end of the transmission component is parallel to a central axis of the proximal shaft and the distal end of the transmission component is at a 22.5 degree angle relative to the central axis of the distal shaft.

13. 2. The shaft of claim 1, wherein the shaft has a circumference of less than 5.6 mm.

14. The shaft of claim 1 , wherein the transmission component is formed as a single piece.

15. A medical hand instrument comprising the shaft of claim 1 and a proximal handpiece.

16. 16. The medical hand instrument of claim 15, wherein the medical hand instrument is a minimally invasive surgical instrument.

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