Medical Tool System

Abstract

The present invention relates to a medical tool system (1) having a tool holder (2) (flexible relative to the distal instrument portion (4)) formed on a distal instrument portion (4) adjacent to a proximal instrument portion (6), and a tool (8) housed in and pivoting relative to the tool holder (2). A first coupling device (10) is disposed on the distal instrument portion (4), and a second coupling device (12) is provided on the tool (8) which, in a coupled state, provides a coupling between the tool (8) and the distal shaft portion (4) by operative engagement with the first coupling device (10) and axially fixes the tool (8) within the distal shaft portion (4).

Description

[Technical field]

[0001] The present disclosure relates to a medical tool system comprising a medical, preferably shaft-shaped, instrument having a distal shaft / instrument portion and a proximal shaft / instrument portion that are bendable relative to one another, and a shaft-type medical tool, e.g., a drill, cutter, screwdriver, etc., axially insertable into a tool chuck of the distal instrument portion and rotatable relative to the tool chuck, and supported in an axially fixed manner. [Background technology]

[0002] Typically, such (medical) tools have a distal tool head / effector and a tool shaft housed in a tool chuck. The tool head protrudes from the tool chuck and can be designed, for example, as a cutter, drill, cutting blade, etc. In this case, the tool chuck holds the tool in a relatively rotatable manner, but does not rotate itself, and is therefore also called a tool holder for simplicity, and is (manually) held by a user to guide the tool, preferably for surgery on a patient. Typically, the tool rotates about its longitudinal axis relative to the tool holder. The rotational movement is transmitted to the tool shaft by a drive unit / drive train arranged in or on the tool holder.

[0003] In surgical techniques, it is advantageous to be able to bend the tool head of a medical hand instrument tool relative to its tool shaft. In other words, the distal portion of the tool / tool ​​shaft will bend relative to the proximal portion of the tool / tool ​​shaft. This allows surgery to be performed in extremely tight spaces, for example in spinal surgery.

[0004] In the field of surgical robotics, instruments have long been known in which the distal tool head can be bent relative to the remainder of the tool shaft, allowing for precise instrument movement even in the tightest of spaces.

[0005] For example, milling tools with bendable tool shafts are known from the disclosures DE 10 2017 010 033 A1 and US 10 178 998 B2. The distal tool head of the milling tool is bendable relative to the proximal milling tool shaft. The milling tool shaft of DE 10 2017 010 033 A1 is inserted into a tool holder of a manually-held and guidable medical instrument, surrounds the milling tool shaft and is axially fixed against withdrawal from the tool holder by a push button provided in the proximal region of the tool holder.

[0006] As mentioned above, a drawback of medical tools in which the tool head is bendable relative to the tool shaft is that the set angle between the tool head and tool shaft often changes undesirably under load.

[0007] For this reason, tool holders for medical hand instruments have been developed, in which the distal instrument section can be bent relative to the proximal instrument section during operation, and the angle between the longitudinal axis of the distal instrument section and the longitudinal axis of the proximal instrument section does not change even under load. In such hand instruments, the tool shaft of the tool is inserted into the tool holder and can be bent relative to the proximal instrument section together with the distal instrument section. Thus, the tool head can be bent relative to the proximal part of the tool shaft together with the tool holder. However, in such medical hand instruments, there is a risk that the tool will be unnecessarily dislodged from the tool holder, especially under load.

[0008] The push-button safety device disclosed in DE 10 2017 010 033 A1 cannot be applied, or cannot be applied in a technically meaningful way, to the bendable tool holders of the above-mentioned medical hand instruments due to the different shapes of the respective tool holders. Summary of the Invention [Problem to be solved by the invention]

[0009] It is therefore an object of the present disclosure to overcome the drawbacks of the prior art and provide a medical shaft tool, a correspondingly designed medical instrument, and a medical tool system, which has a bendable tool holder and a tool inserted therein, where the tool does not unnecessarily come off the tool holder. In particular, it is advantageous to couple the tool to the bendable tool holder in a particularly space-saving manner. [Means for solving the problem]

[0010] According to the present disclosure the object is achieved by a medical tool comprising the features of claim 1, a medical instrument comprising the features of claim 4 and a medical tool system comprising the features of claim 10. Advantageous further embodiments of the present disclosure are subject matter of the attached dependent claims.

[0011] The basic idea of ​​the present invention for axially retaining a tool in a tool holder of a medical instrument is essentially to operatively connect in a click-on manner a rotating element placed on the instrument by a slider to a connecting element acting radially on or in the tool holder on the tool shaft, such that when the rotating element rotates for a first predetermined time, the slider allows the releasing movement of the connecting element and when the rotating element rotates for a second predetermined time different from the first rotation, the slider prevents the releasing movement of the connecting element.

[0012] When this functional principle is applied to a medical instrument having two instrument sections which are mutually rotatable about the longitudinal axis of a tool shaft and which bend relative to one another relative to the longitudinal axis of the shaft, as is known from the prior art mentioned above, the rotation mechanism can be used outside the rotation range provided for bending the two instrument sections in order to actuate the tool coupling mentioned above.

[0013] In other words, bendable instruments are envisaged where the distal instrument part with the tool holder can be bent at an angle relative to the proximal instrument part, for which purpose the proximal instrument part needs to be rotated with respect to the distal instrument part from a design position (e.g. the two instrument parts are aligned) in a specific rotational direction and at a specific rotational angle, so that a rotational movement in the opposite direction from the design position can be used to release the coupling element and axially decouple the tool from the tool holder.

[0014] In particular, firstly a medical shaft tool is proposed, which comprises a distal effector / tool ​​head and a tool shaft arranged and configured to be inserted in a rotating and axially fixed manner into a tool chuck of a medical instrument, preferably a hand instrument, For this purpose a coupling unit is provided which is arranged or can be arranged on the tool shaft, said coupling unit having the following components: Ball bearings or friction bearings to rotationally support the linkage unit housing on the tool shaft. A latch / engagement feature disposed or formed on an exterior surface of the connector unit housing that defines an undercut acting axially, particularly in the proximal direction of the tool shaft.

[0015] This undercut serves as the axial point of application of a coupling / snap-on element on the instrument side to axially retain the tool in the tool holder / tool ​​chuck.

[0016] As a result, a medical instrument, in particular a hand instrument, has also been proposed which comprises a tool chuck / tool ​​holder for selectively receiving a tool shaft as described above, characterised by the following components: An internal torque train configured and adapted to engage the tool shaft in torque transmitting engagement. A first axially movable slider / latch / lock pin that is spring preloaded in a proximal direction. A latch engagement element as said engagement element, preferably a latch ball / lock ball, in operative engagement with the slider / latch / lock pin. As a result, the latch engagement element shifts radially outward to a released position (axially releasing the tool shaft) at a first axial position of the slider / latch / lock pin reached by the spring preload, and the latch engagement element shifts radially inward to a latched position at a second axial position of the slider / latch / lock pin reached against the spring preload.

[0017] Preferably, an actuating housing part rotatable about the tool holder axis relative to the slider / latch / lock pin is provided, in particular a sleeve-like actuating component comprising: An axial front face or contact surface facing the axial end of the slider / latch / locking pin against which a spring preload acts, so that the slider / latch / locking pin is pressed against the end face or contact surface. An axial recess or notch in an end or contact surface into which the slider / latch / locking pin moves as the actuation housing part rotates from its locked position to its released position.

[0018] This structure is particularly simple and less susceptible to manufacturing tolerances, contamination, and / or wear.

[0019] More preferably, the medical instrument has a distal instrument part forming or comprising a tool chuck / tool ​​holder and holding the slider / latch / lock pin axially displaceable, and a proximal instrument part forming or comprising an actuation housing part. The distal and proximal instrument parts are in rotatable axial contact relative to one another at their end faces, the respective abutting end faces of the distal and proximal instrument parts being inclined at mutually equal angles of greater than 0°, preferably 22.5°, to the longitudinal axis of the tool, such that upon relative rotation of the distal and proximal instrument parts, they are angularly displaced relative to one another in the axial direction. Advantageously, both the distal and proximal instrument parts are inclined at 22.5°, so that at maximum relative rotation to one another, more precisely at a relative rotation of 180° between the distal and proximal instrument parts, the angles total up to an adjustment angle of 45°.

[0020] In this case, the axial recess or notch in the front or contact surface of the actuating housing part can be positioned in a circumferential position such that when the distal and proximal instrument parts are angularly adjusted by rotating the actuating housing part (particularly the entire distal instrument part) within a rotation range provided for this purpose, the slider / latch / lock pin cannot be stored in the axial recess or notch, whereas when the distal and proximal instrument parts are angularly adjusted by rotating the actuating housing part (particularly the entire distal instrument part) outside the rotation range provided for this purpose, the slider / latch / lock pin can be moved into the axial recess or notch.

[0021] The present disclosure therefore also relates to a medical tool system with an instrument (possibly with an integrated drive) having a distal and a proximal instrument part that are in particular grippable by a user and bendable relative to a longitudinal axis of the instrument by relative rotation about the longitudinal axis of the tool in order to guide the medical tool system. Furthermore, the medical tool system has a tool housed in a tool holder of the distal instrument part and pivoting relative to the tool holder. In the distal instrument part a first coupling device (as defined above) is arranged and a second coupling device (as defined above) is provided on the tool. In the coupled state the second coupling device implements the fixation of the tool in the axial direction by active engagement / interaction with the first coupling device.

[0022] Due to the interaction of the first coupling device at the distal instrument part and the second coupling device on the tool, the tool is reliably accommodated in the distal instrument part in the axial direction. Thus, the tool cannot accidentally fall off the tool shaft. In particular, it is a great advantage that the tool does not come off in an undesired way from the tool holder when the medical tool system is in operation, and thus avoids injuries to the patient using the medical tool system. The forces that cause the undesired fall off of the tool from the tool holder are mainly tensile forces acting on the distal end of the tool, in particular on the tool head. It is therefore particularly advantageous that the first coupling device is located at the distal instrument part (and not at the proximal instrument part), since the coupling between the tool and the tool holder is placed in the immediate vicinity of the critical force location and can counter this (tensile) force. The coupling at the distal instrument part between the tool and the tool holder is therefore particularly effective and particularly effectively prevents unintended release of the tool from the tool holder.

[0023] In particular, the tool has a tool head and a tool shaft, the tool shaft being received within the tool holder, and the tool head protruding from the distal instrument portion.

[0024] The tool head is thus exposed and particularly useful for application to the patient.

[0025] Furthermore, it is highly useful to further provide a third coupling device on the proximal instrument portion and a fourth coupling device on the proximal portion of the tool, in particular the tool shaft, which, in the coupled state, transmits driving forces / torque to the tool, in particular the tool shaft, by active engagement / interaction with the third coupling device.

[0026] Thus, the connection at the proximal instrument part (between the tool and tool holder) serves to transmit drive force to the tool or tool shaft, preferably within the proximal instrument part, while the connection at the distal instrument part (between the tool and tool holder) serves as an axial lock of the tool on the tool holder.

[0027] It is particularly advantageous if the first connecting device comprises a locking ball and the second connecting device is an axial fixing groove extending at least partially, preferably completely circumferentially, in the circumferential direction of the tool and engaging with the locking ball in the connected state.

[0028] Such a connection between the tool and the distal shaft section is particularly space-saving and can be accommodated in the smallest possible installation space.

[0029] Preferably, the axial locking groove has a semicircular or arcuate cross section. The locking balls are dimensioned such that a part of the locking balls is in full contact with the inner cross-sectional surface of the axial locking groove. In other words, the locking balls and the axial locking groove fit together precisely in terms of shape and dimensions. The locking balls thus fit precisely into the axial locking groove, and the connection between the tool and the tool holder is implemented particularly efficiently.

[0030] It is particularly useful if a second connecting device, more precisely an axial fixing groove, is formed on the bearing housing of the roller bearing unit / housing of the connecting unit on the tool shaft side, which is fixed to the tool axially, i.e. in the direction of the longitudinal axis of the tool shaft (of the distal part), which is arranged in the distal instrument part and allows the tool to be pivoted relative to the distal instrument part, in particular the entire tool holder.

[0031] Pivoting of the tool in the tool holder is meaningful, since when the medical tool system is in operation, the tool is typically pivoted relative to the tool holder. The rotation is usually generated by a drive unit and transmitted to the tool shaft. In this respect, it is particularly advantageous in terms of a precise and effective mounting that a roller bearing unit is provided in the distal instrument part for pivoting the tool in the tool holder. If a roller bearing unit is provided on the tool, in particular on the tool shaft, it is particularly efficient and space-saving for the bearing housing of the roller bearing unit to have the second coupling device, more particularly the axial fixing groove. This is particularly relevant, since the outer diameter of the tool-holding shaft is typically 5.6 mm and the outer diameter of the roller bearing is usually 3 mm. The tool coupling, i.e. the first coupling device and the second coupling device, has to be accommodated in the remaining small installation space minus the wall thickness of the tool holder.

[0032] Preferably, the roller bearing unit has at least one distal roller bearing, in particular a ball bearing, facing the tool head and one proximal roller bearing, in particular a ball bearing, axially spaced apart from the tool head and facing the proximal end of the tool shaft. The two ball bearings can support the tool shaft relative to the tool holder shaft in a particularly efficient and low-friction pivotable manner. Furthermore, the bearing housing ensures a safe and easy insertion of the tool on the tool holder shaft when inserting the tool shaft into the tool holder shaft (coupling process).

[0033] In particular, the roller bearing unit is fixed axially (on the tool shaft) to a distal part of the tool shaft. For axially fixing the roller bearing unit to the tool shaft, two stops may be provided on the tool shaft, preferably spaced apart axially by at least the length of the roller bearing unit, between which the roller bearing unit is arranged. One of the two stops, in particular the stop further from the tool head than the other stop, can be integrally connected to the tool shaft. The other stop is formed separately from the tool shaft and is applied to and connected to the tool shaft after the roller bearing unit has been placed around the tool shaft. Alternatively, both stops can be formed separately from the tool shaft. The stops can be formed separately from the tool shaft and connected to the tool shaft in a form-fit, force-fit or material-fit manner.

[0034] Furthermore, the first coupling device preferably further comprises a locking pin / slider, which is radially fixed and axially movable between a coupled / locked position (holding a locking ball in the axial fixing groove (radially) to achieve the coupled state) and a released position (not holding the locking ball in the axial fixing groove).

[0035] In other words, in the coupled position the distal end of the locking pin / slider is opposite the axial locking groove. In the released position the distal end of the locking pin / slider is not opposite the axial locking groove. In the released position the distal end of the locking pin is opposite a part of the tool shaft (no recess) or a part of the bearing housing of the roller bearing unit (no recess). The locking pin / slider can advantageously prevent unintentional disengagement of the coupling between the tool and the distal instrument part by retaining a locking ball in the axial locking groove. In the disengaged position the locking pin prevents the locking ball from entering the axial locking groove so that the tool can be removed from the tool holder shaft or remain coupled to it.

[0036] The locking pin / slider also preferably has a first locking ball receiving recess at its distal end, through which the locking pin, in the coupled position, radially retains the locking ball in the axial fixing groove, and a second locking ball receiving recess which is (axially) closer to the distal end of the locking pin than the first locking ball receiving recess and is further radially from the tool or bearing housing of the roller bearing unit than the first locking ball receiving recess, and which, in the released position, retains the locking ball radially on the tool or bearing housing but not in the axial fixing groove.

[0037] The first and second locking ball receiving recesses can at least partially surround the locking balls and thus optimally hold them in a desired position. The first locking ball receiving recess is positioned on the locking pin for optimal interaction with the axial fixing groove in the locking pin engagement position. The second locking ball receiving recess is positioned on the locking pin for optimal interaction with the tool shaft or bearing housing of the roller bearing unit in the locking pin / slider release position.

[0038] In particular, the two locking ball receiving recesses preferably have a semicircular or arcuate cross section, respectively. The locking ball is dimensioned such that at least a part of the locking ball is in full contact with the inner cross-sectional surface of the first or second locking ball receiving recess. In other words, the locking ball and the two locking ball receiving recesses match exactly in terms of shape and size. The locking ball thus matches exactly in the first or second locking ball receiving recess, and adjustment of the engagement or release position of the locking pin / slider is particularly effectively implemented.

[0039] It can further be envisaged that the proximal instrument part has, in its distal end region, an edge which holds the locking pin in the coupled position and a locking pin receiving recess which interrupts the edge, as already mentioned above, which receives the proximal end of the locking pin in the released position.

[0040] In other words, the proximal end of the locking pin in the coupled position contacts the edge and is received in the locking pin receiving recess in the released position. The locking pin receiving recess allows the locking pin to move axially towards the proximal instrument part. The distal end of the locking pin then also moves axially towards the proximal instrument part, away from the axial locking groove. As soon as the proximal end of the locking pin is received in the locking pin receiving recess, the distal end of the locking pin no longer faces the axial locking groove and thus the locking pin reaches the released position. The locking pin receiving recess thus allows the realization of a non-coupled state between the tool and the tool holder. On the other hand, the edge allows the coupled state to be maintained.

[0041] Preferably, only one locking pin receiving recess is provided interrupting the edge of the proximal instrument portion.

[0042] If more than one locking pin receiving recess is provided, there will also be multiple circumferential locations where the locking pin can be in the released position, and thus multiple locking pin recesses would impair the manageability and usability of the medical tool system without improving the coupling between the tool and the tool holder.

[0043] Preferably, the locking pin has a protrusion at its proximal end that is smaller in diameter than the remainder of the locking pin and is sized and shaped to be received in the locking pin receiving recess in the released position, such that the locking pin receiving recess can be sized smaller than if it had to accommodate the entire circumference of the locking pin instead of the (smaller) locking protrusion.

[0044] The edge at the distal end of the proximal instrument portion (except for the locking pin receiving recess which interrupts it) is preferably annular. The locking pin receiving recess interrupts this annular shape of the edge. When the edge is so formed or shaped, the axial locking pin positioning can be changed between the released and coupled positions with rotation of the distal shaft portion relative to the proximal instrument portion as the locking pin rotates with the distal instrument portion.

[0045] It is useful for the first connecting device to further comprise a preloading element, in particular a compression spring, preferably a helical spring, which preloads the locking pin in the direction of the proximal shaft portion, thereby biasing the locking pin, preferably the locking protrusion, into the locking pin receiving recess and thus into the released position.

[0046] The preload element ensures that when the locking pin and the locking pin receiving recess are at the same circumferential height, the locking pin actually moves from the axially coupled position towards the proximal instrument part into the locking pin receiving recess and thus into the released position.

[0047] The preload element is thus likewise part of the first connecting device, which thus comprises, in particular, the locking ball, the locking pin and the preload element (spring).

[0048] Preferably, the maximum adjustable angle between the longitudinal shaft axis of the distal shaft portion and the longitudinal shaft axis of the proximal shaft portion is an angle of 45°. Preferably, the predetermined angle for tool unlocking is an angle of (-)18°.

[0049] Conveniently, the locking pin receiving recess has at least one chamfered side.

[0050] The chamfered sides facilitate the locking pin's transition between the released and engaged positions, i.e., the chamfered sides facilitate the locking pin's entry and exit from the locking pin receiving recess.

[0051] Furthermore, the outer peripheral surface of the bearing housing of the roller bearing unit abuts the inner peripheral surface of the distal shaft portion and / or the distal shaft portion itself is provided with an adhesive surface coating, roughened or micro-grooved, which structure can preferably partially absorb the distal tensile force to release the lock-engaging element.

[0052] The compressive forces acting on the tool head when the medical tool system is in operation are directly (radially) transmitted by the roller bearing unit, in particular the proximal roller bearing, to the distal instrument part or its housing. The locking ball thus has to absorb very little compressive forces, but mainly counteracts axial tensile forces. The special properties of the outer circumferential surface of the bearing housing of the roller bearing unit increase the transmission of tensile forces to the inner circumferential surface of the distal instrument part, reducing the forces acting on the locking ball. In particular, the microgrooves are optimally suited to absorbing tensile forces. When using the medical tool system, the tool is loaded not only axially but also radially. Due to the radial force components, the microgrooves are in active engagement with the outer circumferential surface of the bearing housing of the roller bearing unit, which allows a reduction in the load acting on the first coupling device, in particular the locking ball. This improves the coupling between the tool and the tool receiving shaft and improves the axial fixation of the tool in the tool receiving shaft. [Brief description of the drawings]

[0053] [Figure 1] 1 is a longitudinal cross-sectional view of a medical tool system with the tool holder of the tool system aligned and the connection between the tool and the distal instrument portion shown. [Diagram 2] FIG. 1 is a longitudinal cross-sectional view of a medical tool system with the distal instrument section bent at a 45° angle relative to the proximal instrument section and illustrating the connection of the tool to the distal shaft section. [Diagram 3] FIG. 13 is a perspective view of a tool having a roller bearing unit mounted on the tool shaft and a second coupling device. [Figure 4] FIG. 2 is a longitudinal cross-sectional view of the medical tool system with the distal instrument section bent at a predetermined angle α relative to the proximal instrument section, showing the tool and distal shaft sections uncoupled. [Diagram 5] FIG. [Figure 6] FIG. 2 is a perspective view of the distal end of the proximal instrument portion. [Figure 7]FIG. 13 is a top view of the distal end of the proximal instrument portion. [Figure 8] FIG. 2 is a perspective view of a tool and a tool holder. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0054] Preferred embodiments of the present disclosure will now be described with reference to the accompanying drawings.

[0055] In the figures below, for ease of understanding, axial directions A and radial directions R are marked. Unless otherwise stated, axial directions A and radial directions R refer to the distal instrument portion with the tool holder of the medical tool system shown below.

[0056] FIG. 1 is a longitudinal section of a medical tool system 1, in which a tool holder 2 extends in a straight line. The tool holder 2 is housed in a distal instrument part 4 and is followed by a proximal instrument part 6, which are bendable relative to one another. Furthermore, the medical tool system 1 comprises a tool 8, here implemented as a cutter. The tool 8 is housed in a tool holder (tool chuck) 2 and pivots relative to the tool holder 2. A first coupling device 10 is arranged on the distal instrument part 4. A second coupling device 12 is provided on the tool 8 and, in a coupled state, interacts with the first coupling device 10 to realize the coupling between the tool 8 and the distal shaft part 4 and fixes the tool 8 in the distal shaft part 4 in the axial direction A.

[0057] In Fig. 1, the longitudinal axis S1 of the distal instrument part 4 and the longitudinal axis S2 of the proximal instrument part 6 form an angle of 0°. In other words, the tool holder 2 extends in a straight line relative to the proximal instrument part 6. Furthermore, Fig. 1 shows a coupling state between the tool 8 and the distal instrument part 4. This means that the first coupling device 10 mounted on the distal instrument part 4 and the second coupling device 12 provided on the tool 8 are engaged or interacting with each other. The tool 8 comprises a tool head / effector 14, more specifically a cutter head, and a tool shaft 16. The tool head 14 and the tool shaft 16 are connected to each other in a torque-resistant manner.

[0058] From FIG. 1 it can also be seen that the tool shaft 16 pivots in the distal shaft part 4 by means of a roller bearing unit 18. The proximal instrument part 6 carries / contains a drive unit (not shown here) which applies a torque to the tool shaft 16. This torque application causes the tool shaft 16 to rotate relative to the tool holder 2. The roller bearing unit 18 comprises at least one (here precisely two) roller bearings 20 (more precisely ball bearings), which are spaced apart from one another in the axial direction A, but which can alternatively be configured as friction bearings. The roller bearings 20 are accommodated in a bearing housing 22 which is part of the roller bearing unit 18. The second coupling device 12 is inserted in the bearing housing 22 and is not directly arranged on the tool 8. The roller bearing unit 18 and the bearing housing 22 are fixedly arranged on the tool shaft 16 in the axial direction A. However, it can alternatively be envisaged that the second coupling device 12 is directly arranged on the tool shaft 16.

[0059] The second coupling device 12 is configured as an axial locking groove 24 that extends continuously in the circumferential direction of the bearing housing 22. The axial locking groove 24 preferably has a semicircular or arc-shaped cross section. The first coupling device 10 provided on the distal instrument section 4 thus has a locking ball 26. The diameter of the locking ball 26 is selected so that the locking ball 26 can be accommodated in the axial locking groove 24. Preferably, the axial locking groove 24 completely surrounds at least a portion of the locking ball 26 that contacts the axial locking groove 24. In the coupled state, the locking ball 26 is held in the axial locking groove 24 on the opposite side to the axial locking groove 24 by a distal end of a locking pin / slider 28. The locking pin 28 is part of the first coupling device 10. The locking pin 28 is fixed in the radial direction R. The locking pin 28 is arranged so that it is axially displaceable or movable in the distal shaft section 4.

[0060] In the coupled state, the locking ball 26 is received in the axial locking groove 24 and is held radially therein by the locking pin 28. This position of the locking pin 28 in the axial direction A is referred to as the coupled position. An edge 30 at the distal end of the proximal shaft portion 6 prevents the locking pin 28 from moving axially towards the proximal instrument portion 6.

[0061] FIG. 2 is a longitudinal cross-sectional view of the medical tool system 1, in which the longitudinal shaft axis S1 of the distal instrument section 4 is bent at an angle of (+)45° relative to the longitudinal shaft axis S2 of the proximal instrument section 6, showing the coupling state between the instrument 8 and the distal shaft section 4. The 45° angle between the longitudinal shaft axis S1 of the distal instrument section 4 and the longitudinal shaft axis S2 of the proximal instrument section 6 is the maximum adjustable angle due to the selected angle of the mutually facing end faces of the distal and proximal instrument sections 4 and 6 (corresponding to 22.5° relative to the longitudinal instrument axis, respectively). The distal instrument section 4 is bent relative to the proximal instrument section 6 via a rotation mechanism (not described in detail here), and a torque train between the drive section and the tool shaft enables this bending, as shown in FIG. 2. It can be seen in FIG. 2 that the locking ball 26 is held in the axial locking groove 24 in the radial direction R by the locking pin 28, even when the tool holder 2 is bent to the maximum adjustment angle position relative to the proximal instrument section. The tool 8 is thus also fixed in this angular position in the axial direction A in the tool holder 2 by the engagement between the first connecting device 10 and the second connecting device 12 .

[0062] The torque strands towards the tool shaft 16, located in the transition area between the distal instrument section 4 and the proximal instrument section 6, are flexible. This flexible portion of the torque strands allows the distal part of the tool shaft 16 with the tool head 14 to bend together with the distal instrument section 4 relative to the torque strands in the proximal instrument section. At the same time, the flexible portion of the torque strands is implemented in such a way that it is possible to transmit the torque acting on the proximal part of the tool shaft 16 to the tool head 14.

[0063] 3 is a perspective view of the tool 8 with the roller bearing unit 18 mounted on the tool shaft 16. An axial locking groove 24 has been introduced into the bearing housing 22 and is clearly visible here. The axial locking groove 24 extends around the entire circumference of the cylindrical bearing housing 22. The axial locking groove 24 is provided in the proximal half of the bearing housing 22 facing the proximal end of the tool shaft 16.

[0064] 4 is a longitudinal cross-sectional view of the medical tool system 1, in which the distal instrument part 4 is bent at a predetermined angle α relative to the proximal instrument part 6, which angle is set when the proximal instrument part is rotated at about -18°, i.e. opposite to the direction of rotation, at a "proper" bending of the instrument shaft parts, whereby a released state is achieved between the tool 8 and the distal instrument part 4. It will be appreciated that in the released state, the first coupling device 10 and the second coupling device 12 are not in operative engagement with each other. More precisely, the locking balls 26 are not received in the axial fixing grooves 24. Instead, the locking balls 26 are held in the radial direction R against the outer circumferential surface of the bearing housing 22 by the locking pins 28.

[0065] In order for the locking balls 26 to move out of the axial fixing grooves 24 to the release state, starting from the coupled state shown in FIG. 1, the locking pin 28 has to move in the axial direction A towards the proximal instrument part 6. In the coupled state, this is prevented by an edge 30 of the proximal instrument part 6. However, the edge 30 is interrupted at one point by a locking pin receiving recess 32 (see also FIG. 6). If the relative rotation of the two instrument parts about the longitudinal axis S1 of the distal instrument part 4 exceeds the rotation range for the "proper" bending, for example an angle of (-)18°, the locking pin 28 is positioned circumferentially with respect to the proximal instrument part 6 and is flush with the locking pin receiving recess 32. A preload element 34, which is part of the first coupling device 10, biases the locking pin 28 in the axial direction A towards the proximal instrument part 6. The preload element 34 thus presses the locking pin 28, more precisely its proximal end formed as a locking projection 36, into the locking pin receiving recess 32. The position of the lock pin 28 when the lock projection 36 engages with the lock pin receiving recess 32 is referred to as the released position.

[0066] In the released position, the distal end of the locking pin 28 does not face anything against the axial fixing groove 24. This means that the locking ball 26 is not held in the axial fixing groove 24 in the radial direction R. Thus, the tool 8 is not fixed to anything in the axial direction A relative to the distal shaft part 4. Starting from the coupled state, when a tensile force (axial direction A) is applied to the distal end of the tool 8, the locking ball 26 is released from the axial fixing groove 24. Thus, the tool 8 can be separated from the tool holder 2.

[0067] FIG. 5 is a side view of the locking pin 28. At the proximal end of the locking pin 28 a locking projection 36 can be seen. The locking projection 36 is formed in the shape of a finger so as to be able to engage particularly securely and efficiently in the locking pin receiving recess 32 on the proximal instrument part 6. At the distal end, the locking pin 28 has, on the side facing the tool 8, a first locking ball receiving recess 38 and a second locking ball receiving recess 40. Both locking ball receiving recesses 38, 40 have an arcuate or hemispherical cross section and are adapted to the diameter of the locking ball 26. More precisely, the two locking ball receiving recesses 38, 40 are dimensioned so that they completely surround the part of the locking ball 26 in abutment with them.

[0068] The first lock ball receiving recess 38 is disposed on the lock pin 28 to face the axial fixing groove 24 in the coupled position of the lock pin 28. In the coupled position, the first lock ball receiving recess 38 and the axial fixing groove 24 are in close proximity to or in contact with the periphery of the lock ball 26. In the axial direction A, the second lock ball receiving recess 40 is located closer to the distal end of the lock pin 28 than the first lock ball receiving recess 38. The second lock ball receiving recess 40 is located further in the radial direction R from the bearing housing 22 than the first lock ball receiving recess 38. The second lock ball receiving recess 40 is actually the lock ball receiving recess that holds the lock ball 26 against the outer circumferential surface of the bearing housing 22 in the released position.

[0069] FIG. 6 is a perspective view of the distal end of the proximal instrument part 6. An edge 30 can be seen projecting from the distal end of the proximal instrument part 6 in the axial direction A (of the proximal instrument part 6). The edge 30 has an overall annular shape. The annular shape of the edge 30 is interrupted by a locking pin receiving recess 32. The end face of the distal end of the proximal instrument part 6 is chamfered at an angle of incidence relative to the longitudinal axis of the instrument. More precisely, the end face of the distal end of the proximal shaft part 6 has here an angle of incidence of 22.5°, which defines the maximum adjustable angle between the longitudinal axis S1 of the distal instrument part 4 and the longitudinal axis S2 of the proximal instrument part 6 with a 22.5° bevel of the opposite edge of the distal instrument part. Furthermore, a plane E can be seen which bisects the proximal instrument part 6 in the longitudinal direction. This plane E at the same time creates a 0° or 45° angular shape of the distal instrument part 4 relative to the proximal instrument part 6. More precisely, when locking pin 28 (not shown here) lies in plane E, the angle between distal instrument portion 4 and proximal instrument portion 6 is 0° to 45°. Locking pin receiving recess 32 is thus positioned so as not to lie in plane E or to not intersect it. It can be seen that locking pin receiving recess 32 has at least one chamfered side 33, which facilitates the transition of locking pin 28 between the released and coupled positions, or allows the transition all the way in the first place.

[0070] FIG. 7 is a top view of the distal end of the proximal instrument section 6, showing a substantially annular edge 30. The ring shape of the edge 30 is interrupted by an arcuate locking pin receiving recess 32. Furthermore, a plane E is discernible, which can only be represented here as a line. Furthermore, a central axis M can be seen, which divides the arcuate locking pin receiving recess 32 into two equal-sized halves. The plane E and the central axis M include a predetermined rotation angle, e.g., (-)18°. The plane E divides the proximal shaft section 6 into two equally sized instrument section halves 6.1 and 6.2. The locking pin receiving recess 32 is located in the right half 6.2 of the instrument section or shaft section half shown here.

[0071] If the user wants to change the angle between the longitudinal axis S1 of the distal instrument part 4 and the longitudinal axis S2 of the proximal instrument part 6 from a 0° angle or from the maximum adjustable angle of 45° while maintaining the coupled state, the user needs to rotate the distal instrument part 4 relative to the proximal instrument part 6 so that the locking pin 28 remains in the instrument part half 6.1. If the user wants to end the coupled state, the user needs to rotate the distal instrument part 4 relative to the proximal instrument part 6 exactly in the other direction (i.e. in the negative direction), i.e. so that the locking pin 28 moves into the instrument part half 6.2. In doing so, the user needs to rotate until the locking pin 28 or its locking protrusion 36 can engage in the locking pin receiving recess 32.

[0072] 8 is a perspective view of tool 8 and tool holder 2. To assemble medical tool system 1, tool 8 is introduced at its proximal end into opening 42 at the distal end of distal instrument portion 4. Opening 42 is large enough to accommodate roller bearing unit 18 disposed on tool shaft 16. Tool 8 is inserted into tool holder 2 far enough so that tool head 14 protrudes from distal instrument portion 4.

[0073] To couple the tool 8 to the distal instrument part 4, a predefined rotation angle between the distal instrument part 4 and the proximal instrument part 6 must be set or the locking pin 28 (not shown) must be positioned in the release position. Once the tool 8 or its tool shaft 16 is properly seated in the tool holder 2, the rotation angle between the distal instrument part 4 and the proximal instrument part 6 can be reset to the design position (alignment of the instruments in a straight line). By rotating the distal instrument part relative to the proximal instrument part, the locking pin 28 moves out of the locking projection receiving recess 32 via the chamfered side 33. The proximal end or locking projection 36 of the locking pin 28 then contacts the edge 30. By rotating the distal instrument part 4 relative to the proximal instrument part 6, the locking pin 28 (together with the distal instrument part relative to the proximal instrument part) moves from the release position to the coupled position, thus setting up the coupled state between the tool 8 and the tool holder 2. In this coupled state, the tool 8 is axially clamped and fixed in the tool holder 2.

[0074] List of References 1 Medical Tool System 2 Tool holder 4 Distal Instrument Section 6 Proximal Instrument Section 6.1 Left half of the instrument 6.2 Right half of the instrument section 8 Tools 10 First connecting device 12 Second connecting device 14 Tool Head 16 Tool shaft 18 Roller bearing unit / connecting unit 20 Roller Bearings 22 Bearing housing 24 Axial fixing groove 26 Rock Ball 28 Lock pin / slider 30 Edge 32 Locking pin receiving recess 33 Chamfered side 34 Preload element / spring 36 Lock protrusion 38 First lock ball receiving recess 40 Second lock ball receiving recess 42 Aperture A axis direction E plane M center axis R Radial direction S1 Longitudinal axis of distal instrument section S2 Longitudinal axis of proximal instrument section

Claims

1. A medical instrument, particularly a hand instrument, including a tool chuck (2) for selectively receiving a tool shaft (16) of a medical shaft tool (8), comprising: an internal torque train provided and configured to engage in torque transmitting engagement with the tool shaft (16); a first axially, i.e. proximally spring-loaded axially movable slider or locking pin (28); characterised by a lock-engaging element (26), preferably a lock ball, in operative engagement with a slider or lock pin (28); The medical device, wherein at a first axial position of the slider or locking pin (28) reached by the spring preload, the lock engaging element (26) is displaced radially outward to a released position, and at a second axial position of the slider or locking pin (28) reached against the spring preload, the lock engaging element (26) is displaced radially inward to a locked position.

2. It is characterized by an actuating housing part (6), in particular a sleeve-like actuating component, which is rotatable relative to a slider or locking pin (28) around the longitudinal axis of the tool chuck, which an axial front face or contact surface (30) facing the axial end of the spring-loaded slider or locking pin (28), against which the slider or locking pin (28) is pressed; The medical instrument of claim 1, further comprising: an axial recess or notch (32) in the end or contact surface (30), into which the slider or locking pin (28) moves when the actuation housing part (6) rotates for displacement from its locked position to its released position.

3. a distal instrument part (4) forming or comprising a tool chuck (2) and holding in an axially displaceable manner a slider or locking pin (28); a proximal instrument part (6) forming or comprising an operating housing part (6), the distal instrument section (4) and the proximal instrument section (6) are in rotatable axial contact relative to one another at their end faces, the respective abutting end faces of the distal instrument section (4) and the proximal instrument section (6) being inclined at mutually equal angles of greater than 0°, preferably 22.5°, relative to a longitudinal axis of the medical instrument; 3. The medical instrument of claim 2, wherein upon relative rotation of the distal and proximal instrument sections (4, 6) they are angularly displaced relative to one another in the longitudinal direction of the instrument.

4. An axial recess or notch (32) in the front or contact surface (30) of the actuation housing part (6) being located in a circumferential position such that storage of the slider or locking pin (28) in the axial recess or notch (32) is precluded when the angle of the distal instrument portion (4) and the proximal instrument portion (6) are shifted by rotating the actuation housing portion (6) within a rotation range provided for this purpose; 4. The medical instrument according to claim 3, characterized in that the slider or locking pin (28) is arranged in a circumferential position such that it can be accommodated in an axial recess or notch (32) when the angle between the distal instrument part (4) and the proximal instrument part (6) is shifted by rotating the actuation housing part (6) outside the range of rotation provided for this purpose.

5. Bending of the distal instrument portion (4) and the proximal instrument portion (6) is achieved by rotating the actuation housing portion (6) in a first rotational direction, preferably clockwise; 5. The medical instrument according to claim 4, characterized in that the retraction of the slider or locking pin (28) into the axial recess or notch (32) is achieved by rotating the actuation housing part in a second or opposite rotational direction, preferably counterclockwise.

6. 6. The medical instrument according to claim 5, characterized in that the rotation of the actuation housing part to the retracted rotation position of the axial recess or notch (32) relative to the slider or locking pin (28) is less than the maximum rotation range of the actuation housing part (6) provided for bending the instrument parts, preferably (-) 18° from the design position of the actuation housing part (6) in which the two instrument parts (4, 6) are bent at 0° relative to each other.

7. The medical instrument according to any one of claims 1 to 6, characterized in that in the coupled position, the locking pin (28) has a distal end opposite a locking feature (24) formed on the medical tool (8) and receiving the lock-engaging element (26), and in the released position, the distal end is located proximally spaced from the locking feature (24).

8. The locking pin (28) further has a first lock-engaging element receiving recess (38) at its distal end, through which the locking pin (28) radially retains the lock-engaging element (26) in the locked configuration in the coupled position; 8. The medical device according to claim 7, characterized in that in the release position the lock engaging element (26) is radially released.

9. 9. The medical instrument of claim 8, wherein the lock pin (28) further comprises a second lock-engaging element receiving recess (40) at its distal end, which, when viewed axially, is closer to the distal end of the lock pin (28) than the first lock-engaging element receiving recess (38) and which is radially farther from the medical tool (8) than the first lock-engaging element receiving recess (38) so that, in the released position, the lock-engaging element (26) is retained radially on the medical tool (8) and not in the locked configuration (24).

10. A medical device according to any one of claims 1 to 9, 1. A medical tool system comprising: a medical shaft tool (8) having a distal effector (14) and a tool shaft (16) arranged and configured to be inserted in a rotating and axially fixed manner into a tool chuck (2) of a medical instrument, preferably a hand instrument, The medical shaft tool (8) further comprises a coupling unit (18) disposed or positionable on the tool shaft (16), the coupling unit (18) comprising: a roller or friction bearing (20) for rotationally supporting the linkage unit housing (22) on the tool shaft (16); A locking feature (24) disposed or formed on the outer circumferential surface of the connection unit housing (22) and defining an undercut acting axially, in particular in the proximal direction of the tool shaft.

11. the tool chuck (2) protrudes radially inwards and forms a preferably annular circumferential stop against which a proximal bearing unit on the shaft (16) of the medical tool (8) abuts axially when it reaches its intended receiving position in the tool chuck (2); The medical tool system of claim 10, characterized in that it provides an axial force transmission bridge for proximal compressive forces from the effector (14) through a stop in the tool chuck (2).

12. 12. The medical tool system according to claim 11, characterized in that the tool chuck (2) has or forms a receiving sleeve, the inner diameter of which is adapted to the outer diameter of the coupling unit housing (22) on the tool shaft side for a substantially backlash-free insertion.

13. A medical tool system according to any one of claims 10 to 12, characterized in that the outer circumferential surface of the connection unit housing (22) of the connection unit (18) which abuts the inner circumferential surface of the distal instrument section (4) and / or the distal instrument section (4) itself is provided with an adhesive surface coating, roughened or has micro-grooves.

14. The roller bearing or friction bearing (20) has two axially spaced bearing units with a spacer sleeve disposed therebetween; In the preferred case of roller bearings, each of the axially spaced bearing units having an inner ring, an outer ring and a ball ring disposed therebetween; The spacer sleeves are axially supported against each of the inner rings; A medical tool system according to any of claims 10 to 13, characterized in that the outer ring is inserted into the connection unit housing (22).

15. The medical tool system according to any one of claims 10 to 14, characterized in that the connection unit housing (22) has a cylindrical shape and the undercut is formed as a locking / engagement shape by a groove (24) circumferentially around the outer periphery of the connection unit housing (22).

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