Actuating element, surgical instrument and method for producing the actuating instrument

Description

FIELD OF THE INVENTION

[0001] The present invention relates to a force transmission element with combined mechanical bearing and electrical separation, as well as a surgical instrument comprising the force transmission element and a method for producing the force transmission element. TECHNICAL BACKGROUND

[0002] Surgical instruments often have mechanical bearings, particularly anti-rotation devices or axial guides with stops. Surgical instruments also often have electrical isolation (insulation). The mechanical bearings and electrical isolation are implemented by separate components or elements of the surgical instrument.

[0003] For example, tubular-shaft surgical instruments (e.g., endoscopic instruments) with a tubular shaft and a force-transmitting element mounted therein have an anti-rotation device that prevents the force-transmitting element from rotating relative to the tubular shaft. Furthermore, such tubular-shaft surgical instruments can additionally or alternatively have an axial guide with a stop that guides the force-transmitting element in the tubular shaft, preferably centrally, in the axial direction and limits its translational movement by means of one or two stops. DE 10 2014 116065 A1 discloses a bipolar surgical instrument with a reusable handle and a disposable tool, as well as a connecting device therebetween.

[0004] Furthermore, for example, bipolar surgical tubular shaft instruments (e.g., endoscopic instruments with bipolar tools / accessories) have two electrical leads, which are usually formed by two electrically insulated components or elements of the surgical tubular shaft instrument. In bipolar surgical tubular shaft instruments, two electrodes (active electrode and neutral electrode) are arranged on the accessory of the surgical tubular shaft instrument. High-frequency alternating current can be introduced into the target tissue from a first electrode (active electrode) directly opposite the second electrode (neutral electrode).

[0005] In bipolar-operated surgical tubular shaft instruments with a tubular shaft configured as a first electrical line and a power transmission element mounted therein configured as a second electrical line, an anti-twist device or axial guide for the power transmission element is provided in the tubular shaft, and a separate electrical separation or insulation of the power transmission element from the tubular shaft is provided. Thus, additional individual parts and connections are arranged in such surgical tubular shaft instruments to implement both functions: mechanical guidance and electrical separation. SUMMARY OF THE INVENTION

[0006] Against this background, the present invention is based on the object of providing an improved medical instrument with combined mechanical bearing and electrical separation.

[0007] According to the invention, this object is achieved by an actuating element having the features of patent claim 1 and / or by a surgical instrument having the features of patent claim 9 and / or by a method having the features of patent claim 12.

[0008] Accordingly, according to a first aspect of the present invention, a force transmission element for surgical instruments is provided, comprising a rod, electrical insulation, and a sleeve. The rod is electrically conductive and designed for force transmission. The electrical insulation extends circumferentially over an outer surface and at least partially in the axial direction along the rod. The sleeve is electrically conductive. The sleeve is arranged circumferentially around the electrical insulation and extends at least partially in the axial direction along the electrical insulation. The rod has at least one recess. The insulation extends at least along the recess. The sleeve has an embossed portion which extends at least partially into the recess and is designed for engagement with a securing element of a surgical instrument.

[0009] Furthermore, according to a second aspect of the present invention, a surgical instrument, in particular a tubular-shaft surgical instrument, is provided with a force transmission element according to the first aspect of the present invention, a tubular shaft, a securing element, a tool, and an actuation interface. The force transmission element is received in the tubular shaft. The securing element is mounted in the tubular shaft and engages the embossed portion of the sleeve of the force transmission element. The tool is movable by means of the force transmission element. The actuation interface is designed to actuate the force transmission element.

[0010] Furthermore, according to a third aspect of the present invention, a method for producing a force transmission element for surgical instruments, in particular a force transmission element according to the first aspect of the present invention, is provided, which comprises the following steps: Providing an electrically conductive rod configured for force transmission, which has a recess. Applying electrical insulation circumferentially over an outer surface and at least partially in the axial direction along the rod, such that the insulation extends at least along the recess. Circumferentially arranging an electrically conductive sleeve around the insulation at least partially in the axial direction along the electrical insulation. Embedding an embossing into the sleeve, which engages at least partially in the recess and is configured for engagement with a securing element of a surgical instrument.

[0011] The rod can be made at least partially of a metallic material such as steel or stainless steel. The rod can be designed, in particular, to transmit a force in the axial direction (tensile or compressive) and, additionally or alternatively, a torque. The force in the axial direction or the torque can be transmitted from the actuation interface to the rod and forwarded through the rod to an accessory or tool of the surgical instrument in order to move the accessory or tool.

[0012] The recess in the rod serves to restrict or block at least one translational or rotational degree of freedom of the rod relative to the sleeve. The rod is supported relative to the sleeve in the area of ​​the recess and the embossed groove engaging there, and is additionally or alternatively guided. The recess can be created in the rod using a machining process such as milling.

[0013] The insulation can be made at least partially from a polymeric material such as polytetrafluoroethylene (PTFE, Teflon) or a ceramic material. The insulation electrically separates the electrically conductive rod from the electrically conductive sleeve. Particularly in bipolar operation of the surgical tool, the electrical current can be conducted via the force-transmitting element by electrically connecting one of the two poles for conducting the electrical current to the rod and the other of the two poles for conducting the electrical current to the sleeve, which is electrically separated from the rod by the electrical insulation.

[0014] The insulation is arranged circumferentially on the surface of the rod. The insulation is arranged at least in a section along the rod that extends at least over part of the recess. The insulation touches the surface of the rod and, in the region of the recess, the insulation is also in contact with the surface of the recess or of the rod. In particular, the insulation is firmly mechanically connected to the rod (e.g., press fit). The insulation is thus applied to the rod in such a way that it circumferentially encloses the rod, at least in the region of the recess. The application can be achieved, for example, by coating or shrinking on a heat-shrink tube. The insulation can have a substantially constant thickness along the circumference of the rod. Accordingly, the embossing of the sleeve engages in the recess of the rod in such a way that the embossing with the insulation is not in contact with the rod.

[0015] The sleeve can be made at least partially from a metallic material such as steel or stainless steel. The sleeve is arranged circumferentially in an area around the rod with insulation, which area encompasses at least a section of the recess. The bore of the sleeve in the axial direction is in particular arranged concentrically. The sleeve is either firmly mechanically connected to the insulation (e.g. press fit) or allows displacement or rotation of the rod with the insulation relative to the sleeve with a predefined sliding friction (e.g. clearance fit) in the bore of the sleeve. For this purpose, the sleeve is pushed onto the rod and advanced far enough that it is at least partially arranged in the area of ​​the recess.

[0016] The embossing is embossed into the sleeve in such a way that the embossing engages in the recess, whereby the embossing only contacts the insulation around the rod and not the rod itself. In particular, the embossing engages in the recess in a radial direction. The embossing and the recess form a bearing or guide for the rod relative to the sleeve, with the insulation being in contact with both and separating them from each other. The rod is therefore supported or guided with the insulation in the sleeve at least in the area of ​​the recess and the embossing engaging therein. The sleeve can be embossed, for example, by a stamp in a predefined section of the circumference of the sleeve or completely by roll stamping.

[0017] The force transmission element is inserted into the tubular shaft of the surgical instrument. The force transmission element is supported or guided in the tubular shaft, at least via the sleeve. The sleeve can be electrically insulated from the tubular shaft. In particular, the sleeve is supported or guided in the tubular shaft in such a way that it, or the force transmission element, can move or rotate axially relative to the tubular shaft. Thus, the force transmission element can transmit an axial force (tensile or compressive) and, additionally or alternatively, a torque within and relative to the tubular shaft.

[0018] To prevent unintentional displacement or rotation of the force transmission element relative to the tubular shaft, which could, for example, lead to the force transmission element slipping out of the tubular shaft, the sleeve and thus the force transmission element are secured in the tubular shaft by the locking element. For this purpose, the locking element mounted in the tubular shaft engages the embossing of the sleeve. For example, the locking element can be mounted so that it can move radially relative to the tubular shaft and engage the embossing in the radial direction. In particular, the locking element can be preloaded in the radial direction, for example, by means of an elastic spring ring.

[0019] The tool, which can particularly be designed as an interchangeable accessory, is moved by the axial force or torque transmitted via the force transmission element within and relative to the tubular shaft. The tool can be designed as a clamp, forceps, tweezers, gripper, scissors, and the like. In particular, the tool can also be designed for bipolar operation, for example, to cut or cauterize tissue, and the like.

[0020] The actuation interface is used to actuate the force transmission element by applying an axial force or torque to the force transmission element.

[0021] If the surgical instrument is to be operated by a user, such as a surgeon, the surgical instrument includes a handle for the user. The actuation interface then transmits a force or torque, which is applied by the user to the handle via a suitable actuation (e.g., a movable handle limb), to the force transmission element.

[0022] If the surgical instrument can be connected to a robot, the surgical instrument comprises a corresponding connection interface for the robot, which can apply an axial force or torque to the force transmission element via the actuation interface.

[0023] The force transmission element according to the invention, comprising a rod, insulation, and sleeve, is particularly easy to manufacture, as only the insulation needs to be applied to the rod, the sleeve then positioned on top, and finally the embossing in the area of ​​the rod's recess needs to be embossed. Furthermore, the force transmission element according to the invention eliminates the need for a separate component for guiding and electrically insulating the force transmission element from the tubular shaft of the surgical instrument. This advantageously avoids increased production and manufacturing costs due to additional individual parts and connections. Furthermore, failure of the affected tubular-shaft surgical instrument due to mechanical stress on said connections, which are typically subject to high mechanical loads, is also advantageously avoided.

[0024] Advantageous further developments and embodiments of the present invention are the subject of the corresponding dependent patent claims.

[0025] According to a further development of the present invention, the rod of the force transmission element is designed as a round rod. The electrical insulation extends, at least in sections, circularly along the surface of the rod. The sleeve is designed as a round tube and extends, at least in sections, circularly along the surface of the electrical insulation.

[0026] According to a further development, the tubular shaft is designed as a round tube. The rod of the force transmission element is designed as a round rod. The electrical insulation extends, at least in sections, circularly along the surface of the rod. The sleeve is designed as a round tube and extends, at least in sections, circularly along the surface of the electrical insulation. The force transmission element is arranged concentrically in the tubular shaft.

[0027] The rod, designed as a round rod, has a substantially circular cross-section with a substantially constant diameter along the axial direction, except in the region of the recess.

[0028] The insulation is arranged circularly and in particular concentrically around the rod, particularly away from the recess.

[0029] The sleeve, designed as a round tube, has a substantially circular cross-section with a substantially constant diameter along the axial direction, except in the area of ​​the embossing. The sleeve, designed as a round tube, is arranged circularly and, in particular, concentrically around the insulation.

[0030] The tubular shaft, designed as a round tube, has a substantially circular cross-section with a substantially constant diameter along the axial direction. The force transmission element, comprising a round rod and a round tube sleeve, is arranged concentrically within the tubular shaft. The locking element engages radially in the embossing to secure the force transmission element, comprising the round rod and the round tube sleeve, within the tubular shaft.

[0031] The force transmission element and surgical instrument designed in this way are advantageously particularly easy to manufacture.

[0032] According to a further development, the embossing is designed to block at least the rotational degree of freedom about an axis parallel to the sleeve or the axial direction of the sleeve upon engagement of a securing element.

[0033] The locking element of the surgical element engages the embossing in such a way that rotation of the sleeve and, depending on the design of the recess, also of the rod relative to the tubular shaft is blocked. Thus, at most, an axial displacement of the sleeve and, depending on the design of the recess, also of the rod relative to the tubular shaft is possible.

[0034] In this way, unwanted rotations of the sleeve or the entire force transmission element relative to the tool or accessories of the surgical element can be avoided and thus a proper function of the tool / accessory can be ensured.

[0035] According to a further development, the embossed portion has at least one substantially planar section for making substantially flat contact with a planar surface of a securing element. The substantially planar section runs parallel to the axial direction of the sleeve and is located radially further inward than the outer surface of the sleeve.

[0036] The essentially flat section can be created in the rod or round rod, for example, by face milling. The essentially flat section forms a flat contact surface. If this contact is made, preferably flat, by the also essentially flat surface of the securing element, which is preloaded radially inward onto the sleeve, the sleeve and, depending on the design of the recess, the rod are secured against rotation / twisting relative to the tubular shaft of the surgical instrument.

[0037] This design of the embossing thus advantageously enables a particularly easy-to-manufacture anti-twist device.

[0038] According to a further development of the present invention, the recess has at least one substantially planar section parallel to the axial direction of the rod. The substantially planar section is located further inward in the radial direction relative to the outer surface of the rod and is in contact with the substantially planar section of the embossed portion in abutting, in particular flush, manner.

[0039] If the sleeve is secured against rotation or twisting in the tubular shaft via the substantially flat section of the embossing and the securing element with a substantially flat surface of the surgical element, the rod is also secured against rotation / twisting via its substantially flat section and via the substantially flat section of the embossing relative to the tubular shaft.

[0040] According to a further development of the present invention, the embossing is designed to limit or block at least the translational degree of freedom in a direction parallel to the sleeve or the axial direction of the sleeve upon engagement of a securing element.

[0041] The locking element of the surgical element engages the embossing in such a way that axial displacement of the sleeve and, depending on the design of the recess, also of the rod relative to the tubular shaft is limited or blocked. In one embodiment, rotation of the sleeve and, depending on the design of the recess, also of the rod relative to the tubular shaft may be possible.

[0042] In this way, unwanted axial displacements of the sleeve or the entire force transmission element relative to the tool or accessories of the surgical element can be avoided and thus a proper function of the tool / accessory can be ensured.

[0043] According to a further development, the embossed portion has at least one stop. The at least one stop of the embossed portion is designed to block or limit at least the translational degree of freedom parallel to the sleeve or the axial direction of the sleeve upon engagement of the securing element.

[0044] If the locking element rests with at least one of its flanks in the axial direction against the stop of the embossed portion, axial displacement of the sleeve relative to the tubular shaft (in the direction with the stop towards the locking element) is no longer possible. In particular, if two stops of the embossed portion are provided that are opposite one another in the axial direction, the axial movement of the sleeve relative to the tubular shaft is at least limited in both axial directions of movement. If the two stops that are opposite one another in the axial direction are arranged in such a way that they always rest against the two flanks of the locking element that are aligned in the axial direction, the translational degree of freedom of the sleeve relative to the tubular shaft is blocked and not just limited.

[0045] According to a further development of the present invention, the recess has at least one stop. The at least one stop of the recess is designed, together with the embossing, to limit or block at least the translational degree of freedom in a direction parallel to the rod or to the axial direction of the rod.

[0046] If the embossing rests with its at least one stop in the axial direction against the stop of the recess, no axial displacement of the rod relative to the sleeve in the direction with the stop of the recess towards the stop of the embossing is possible. In particular, if there are two stops of the recess opposite each other in the axial direction, the axial movement of the rod relative to the sleeve is at least limited in both axial directions of movement. If the two stops of the recess opposite each other in the axial direction are arranged in such a way that they rest equally against the two stops of the embossing, the translational degree of freedom of the rod relative to the sleeve is blocked and not just limited.

[0047] According to a further development of the present invention, the electrical insulation has sliding properties on its outer surface, at least in the region of the embossing. Additionally or alternatively, the sleeve has sliding properties on its inner surface, at least in the region of the embossing.

[0048] The sliding properties of the outer surface of the electrical insulation or the inner surface of the embossing can be ensured by a suitable choice of material (e.g., PTFE for the electrical insulation) and, additionally or alternatively, by suitable treatment of the respective surface (e.g., polishing, honing, etc.). For example, the electrical insulation can be made of PTFE and the sleeve of stainless steel. Furthermore, the inner surface of the sleeve can be polished. The polished inner surface of the stainless steel sleeve can then slide easily on the outer surface of the PTFE insulation, allowing for smooth axial displacement or rotation of the sleeve relative to the electrical insulation.

[0049] According to a further development of the present invention, the securing element has sliding properties on its surface facing the embossing. Additionally or alternatively, the embossing has sliding properties on its outer surface.

[0050] The sliding properties of the surface of the locking element facing the embossing or the outer surface of the embossing can be ensured by a suitable choice of material and additionally or alternatively by suitable treatment of the respective surface (e.g., polishing, honing, etc.). For example, the sleeve and the locking element can be made of stainless steel, and the outer surface of the sleeve and the surface of the locking element facing the embossing can be polished. The polished outer surface of the stainless steel sleeve can then slide easily on the surface of the stainless steel locking element facing the embossing, enabling smooth axial displacement or rotation of the sleeve relative to the locking element or the tubular shaft of the surgical instrument.

[0051] According to a further development of the present invention, the step of providing comprises a step of creating the recess in the rod, in particular by forming, for example pressing, or by machining, for example milling or turning.

[0052] According to a further development of the present invention, the step of applying the insulation comprises shrinking a shrink tube onto the rod or coating the rod.

[0053] According to a further development of the present invention, the step of circumferentially arranging comprises the following steps: Heat the sleeve until, due to thermal expansion, the inner diameter of the sleeve is larger than the outer diameter of the electrical insulation. Slide the heated sleeve onto the electrical insulation. Cool the heated and pushed-on sleeve.

[0054] The heated sleeve is pushed onto the rod with the electrical insulation until it is at least partially positioned within the rod's recess. Once the pushed-on sleeve has cooled, a press fit, i.e., a tight mechanical connection, or a loose fit, i.e., a sliding connection, exists between the sleeve and the electrical insulation. TABLE OF CONTENTS OF THE DRAWING

[0055] The present invention will be explained in more detail below with reference to the exemplary embodiments shown in the schematic figures of the drawing. In the drawings: Fig. 1 shows a side view of a hand-held surgical instrument; Fig. 2 shows a longitudinal section through the surgical instrument; Fig. 3 shows an isometric view of a first embodiment of the force transmission element of the surgical instrument; Fig. 4A shows a longitudinal section through a first variant of the first embodiment of the force transmission element; Fig. 4B shows a longitudinal section through a second variant of the first embodiment of the force transmission element; Fig. 4C shows a cross-section through the first embodiment of the force transmission element in the region of the embossing; Fig. 5 shows an isometric view of a second embodiment of the force transmission element; Fig. 6A shows a longitudinal section through a first variant of the second embodiment of the force transmission element; Fig. 6B shows a longitudinal section through a second variant of the second embodiment of the force transmission element;Fig. 6C shows a cross section through the second embodiment of the force transmission element in the region of the embossing; Fig. 7 shows an isometric view of a third embodiment of the force transmission element; Fig. 8A shows a longitudinal section through a first variant of the third embodiment of the force transmission element; Fig. 8B shows a longitudinal section through a second variant of the third embodiment of the force transmission element; Fig. 8C shows a cross section through the third embodiment of the force transmission element in the region of the embossing; Fig. 9 shows an isometric view of a fourth embodiment of the force transmission element; Fig. 10 shows a longitudinal section through the fourth embodiment of the force transmission element; and Fig. 11 shows a flow diagram of an embodiment of the method for producing a force transmission element.

[0056] The accompanying drawing figures are intended to provide a further understanding of embodiments of the invention. They illustrate embodiments and, in conjunction with the description, serve to explain principles and concepts of the invention. Other embodiments and many of the noted advantages will become apparent upon review of the drawings. Elements of the drawings are not necessarily shown to scale relative to one another.

[0057] In the figures of the drawing, identical, functionally identical and acting elements, features and components are provided with the same reference symbols, unless otherwise stated. DESCRIPTION OF EMBODIMENTS

[0058] In Fig. 1 A hand-held surgical instrument 10 is shown schematically. The surgical instrument comprises a force transmission element (not shown here, see Figs. 2 bis 10 ), a tubular shaft 11, a securing element (not shown here, see Fig. 2 ), a tool or accessory 13, a handle 14, a movable handle limb 15 and an accessory interface 16.

[0059] The force transmission element is accommodated and mounted in the tubular shaft 11 (see Fig. 2 ). The locking element secures the force transmission element against twisting and additionally or alternatively against axial displacement relative to the tubular shaft 11 (see Fig. 2 ). The tool 13 is designed here as a gripper which can be supplied with bipolar electrical current via the force transmission element. The surgical instrument is equipped with a handle 14 for manual guidance by a user (e.g. surgeon). Alternatively, the surgical instrument 10 can be equipped with a corresponding connection interface for the robot (not shown) for guidance by a robot. The movable handle leg 15 is used for manual force introduction. The force applied to the handle leg 15 is transmitted via the handle leg 15 to the force transmission element. The force transmission element, in turn, transmits the axial force to the tool / accessory. In addition, two electrical poles of a bipolar generator (not shown) are connected to the tool via the force transmission element.The tool / accessory 13 can be releasably mechanically connected to the handle 14 via the accessory interface 16.

[0060] In Fig. 2 is a longitudinal section through the surgical instrument 10 from Fig. 1 shown schematically in the area of ​​the accessory interface 16.

[0061] The force transmission element 1 is housed and guided in the tubular shaft 11, which is designed as a round tube. The force transmission element 1 is secured by the locking element 12 guided in the tubular shaft 11. The force transmission element 1 comprises a rod 2, an electrical insulation 3, and a sleeve 4.

[0062] Rod 2 is designed as a round rod and made of stainless steel. An axial force, for example from the movable handle leg (not shown here, see Fig. 1 ) to the tool (not shown here, see Fig. 1 ). Furthermore, one of two electrical poles of the bipolar generator can be connected to the tool via the rod 2. The rod 2 has a recess 5. The recess 5 can have different shapes (see Figs. 3 bis 10 ).

[0063] The electrical insulation 3 is made of PTFE and is arranged circumferentially, here circularly and concentrically, around the rod. The material could also be PFA or a similar material. The electrical insulation 3 is mechanically firmly connected to the rod 2 and electrically separates the rod 2 from the sleeve 4. The electrical insulation 3 is also arranged around the rod 2 in the area of ​​the recess 5 and is mechanically firmly connected to it.

[0064] The sleeve 4 is made of stainless steel and is arranged circumferentially, here circularly and concentrically, around the electrical insulation 3. The sleeve 4 has a recess 6 in the area of ​​the recess 5, which engages into the recess 5. The sleeve 4 is in contact over its entire length only with the electrical insulation 3 and not with the rod 2. The other of the two electrical poles of the bipolar generator can be connected to the tool via the sleeve 4. The recess 6 has a distal stop 7A and a proximal stop 7B.

[0065] The securing element 12 is preloaded in the distal direction toward the force transmission element 1 via an annular spring 17 and engages the embossing 6. A surface 12A of the securing element 12 facing the embossing rests on the outer surface of the embossing 6. The surface 12A of the securing element 12 facing the embossing can be substantially flat, and the outer surface of the embossing 6 can comprise a substantially flat section 6A, such that the surface 12A of the securing element 12 facing the embossing rests substantially flat on the substantially flat section 6A of the embossing 6. As a result, the rotational degree of freedom about the longitudinal axis of the sleeve is blocked, and the sleeve 4 is thus secured against rotation / twisting relative to the tubular shaft 11.

[0066] A distal flank of the securing element 12 limits the translational degree of freedom of the sleeve in the axial direction together with the distal stop 7A of the embossing 6. A proximal flank of the securing element 12 limits the translational degree of freedom of the sleeve in the axial direction together with the proximal stop 7B of the embossing 6. In Fig. 2 The proximal flank of the securing element 12 is shown resting against the proximal stop 7B of the embossed portion 6. Therefore, the sleeve 4 cannot be displaced further distally relative to the tubular shaft 11.

[0067] The extent to which the rod 2 is translationally or rotationally restricted or blocked relative to the sleeve 4 depends on the respective embodiment of the force transmission element 1. Four different embodiments of the force transmission element 1 are described below.

[0068] In the Figs. 3, 4A, 4B und 4C A first embodiment of the force transmission element 1 is shown schematically.

[0069] The recess 5 in the rod 2 is circular and has a distal stop of the embossed portion 5 and a proximal stop of the embossed portion. For example, the recess 5 in the rod 2 can be created by turning.

[0070] The electrical insulation 3 lies circularly and concentrically on the rod 2 also in the area of ​​the recess 5.

[0071] The embossing 6 in the sleeve 4 is circular with a distal stop 7A of the embossing 6 and a proximal stop 7B of the embossing 6 and can be formed, for example, by roll embossing with one or more rotating rollers.

[0072] In Fig. 4A A longitudinal section through a first variant of the first embodiment of the force transmission element 1 is shown schematically. The sleeve 4 has an embossed portion 6 which engages in the entire recess 5, wherein the sleeve 4 rests against the electrical insulation 3. The distal stop 7A of the sleeve 4 rests against a distal stop 8A of the rod 2 or the insulation 3 in this area. Likewise, the proximal stop 7B of the sleeve 4 rests against a proximal stop 8B of the rod 2 or the insulation 3 in this area. The degree of freedom in the axial direction of the rod 2 relative to the sleeve 4 is thus blocked. Depending on the sliding properties between the electrical insulation 3 and the sleeve 4, the rod 2 with the insulation 3 can be rotated relative to the sleeve 4.

[0073] In Fig. 4B A longitudinal section through a second variant of the first embodiment of the force transmission element 1 is shown schematically. The sleeve 4 has an embossed portion 6 which engages in the recess 5 only in one section, with the sleeve 4 resting against the electrical insulation 3. The distal stop 7A of the sleeve 4 does not rest against the distal stop 8A of the rod 2 or the insulation 3 in this area. Likewise, the proximal stop 7B of the sleeve 4 does not rest against the proximal stop 8B of the rod 2 or the insulation 3 in this area. The degree of freedom in the axial direction of the rod 2 relative to the sleeve 4 is thus only limited between the stops but not completely blocked. Depending on the sliding properties between the electrical insulation 3 and the sleeve 4, the rod 2 with the insulation 3 can be rotated relative to the sleeve 4.

[0074] In Fig. 4C A cross-section through the first embodiment of the force transmission element 1 is schematically shown in the area of ​​the embossing 6. The embossing 6 lies circularly and concentrically against the electrical insulation 3.

[0075] In the Figs. 5, 6A, 6B und 6C A second embodiment of the force transmission element 1 is shown schematically.

[0076] The recess 5 in the rod 2 is circular and has a distal stop of the recess 5 and a proximal stop of the recess 5. For example, the recess 5 in the rod 2 can be created by turning.

[0077] The electrical insulation 3 lies circularly and concentrically on the rod 2 also in the area of ​​the recess 5.

[0078] The embossing 6 in the sleeve 4 here comprises four flat embossings 6.1, 6.2 (two of the four flat embossings not shown) evenly distributed over the circumference as well as a distal stop 7A of the embossing 6 and a proximal stop 7B of the embossing 6. The flat embossings 6.1, 6.2 can be formed, for example, by embossing with one or more punches.

[0079] In Fig. 6A A longitudinal section through a first variant of the second embodiment of the force transmission element 1 is shown schematically. The sleeve 4 has the four flat embossments 6.1, 6.3 (two of the four flat embossments not shown) which engage in the entire recess 5, wherein the sleeve 4 rests against the electrical insulation 3. The distal stop 7A of the sleeve 4 rests against the distal stop 8A of the rod 2 or the insulation 3 in this area. Likewise, the proximal stop 7B of the sleeve 4 rests against the proximal stop 8B of the rod 2 or the insulation 3 in this area. The degree of freedom in the axial direction of the rod 2 relative to the sleeve 4 is thus blocked. Depending on the sliding properties between the electrical insulation 3 and the sleeve 4, the rod 2 with the insulation 3 can be rotated relative to the sleeve 4. The rotation can also be blocked.

[0080] In Fig. 6B A longitudinal section through a second variant of the second embodiment of the force transmission element 1 is shown schematically. The sleeve 4 has the four flat embossings 6.1, 6.3 (two of the four flat embossings not shown), which engage in the recess 5 only in one section, with the sleeve 4 abutting the electrical insulation 3. The distal stop 7A of the sleeve 4 does not abut the distal stop 8A of the rod 2 or the insulation 3 in this area. Likewise, the proximal stop 7B of the sleeve 4 does not abut the proximal stop 8B of the rod 2 or the insulation 3 in this area. The degree of freedom in the axial direction of the rod 2 relative to the sleeve 4 is thus only limited between the stops but not completely blocked. Depending on the sliding properties between the electrical insulation 3 and the sleeve 4, the rod 2 with the insulation 3 can be rotated relative to the sleeve 4. The rotation can also be blocked.

[0081] In Fig. 6C A cross-section through the second embodiment of the force transmission element 1 in the area of ​​the flat embossings 6.1, 6.2, 6.3, 6.4 is schematically shown. The flat embossings 6.1-6.4 lie against the electrical insulation 3 and can be formed, for example, by embossing with one or more dies.

[0082] A locking element engaging in one of the flat impressions 6.1, 6.2, 6.3, 6.4 with a flat surface facing the impression blocks the rotational degree of freedom of the sleeve 4, but not of the rod 2, relative to the tubular shaft.

[0083] In the Figs. 7, 8A, 8B und 8C A third embodiment of the force transmission element 1 is shown schematically.

[0084] The rod 2 comprises four recesses evenly distributed over the circumference, as well as a distal stop of the recess and a proximal stop of the recess.

[0085] For example, the recesses in the rod 2 can be created by milling.

[0086] The electrical insulation 3 lies circularly and concentrically on the rod 2 also in the area of ​​the recesses.

[0087] The embossing 6 in the sleeve 4 here comprises four flat embossings 6.1, 6.2 (two of the four flat embossings not shown) evenly distributed over the circumference, as well as a distal stop 7A of the embossing 6 and a proximal stop 7B of the embossing 6. The flat embossings 6.1, 6.2 can be formed, for example, by embossing with one or more punches.

[0088] In Fig. 8A A longitudinal section through a first variant of the third embodiment of the force transmission element 1 is shown schematically. The sleeve 4 has the four flat embossments 6.1, 6.3 (two of the four flat embossments not shown), each of which engages in one of the four recesses 5.1, 5.3 (two of the four recesses not shown), whereby the sleeve 4 bears against the electrical insulation 3. The distal stop 7A of the sleeve 4 bears against the distal stop 8A of the rod 2 or the insulation 3 in this area. Likewise, the proximal stop 7B of the sleeve 4 bears against the proximal stop 8B of the rod 2 or the insulation 3 in this area. The degree of freedom in the axial direction of the rod 2 relative to the sleeve 4 is thus blocked. Depending on the sliding properties between the electrical insulation 3 and the sleeve 4, the rod 2 with the insulation 3 can be rotated relative to the sleeve 4.

[0089] In Fig. 8B A longitudinal section through a second variant of the third embodiment of the force transmission element 1 is shown schematically. The sleeve 4 has the four flat embossments 6.1, 6.3 (two of the four flat embossments not shown), each of which engage in only one section of the corresponding recess 5.1, 5.3 (two of the four recesses not shown), wherein the sleeve 4 rests against the electrical insulation 3. The distal stop 7A of the sleeve 4 does not rest against the distal stop 8A of the rod 2 or the insulation 3 in this area. Likewise, the proximal stop 7B of the sleeve 4 does not rest against the proximal stop 8B of the rod 2 or the insulation 3 in this area. The degree of freedom in the axial direction of the rod 2 relative to the sleeve 4 is thus only limited between the stops but not completely blocked.Depending on the sliding properties between electrical insulation 3 and sleeve 4, the rod 2 with the insulation 3 can be rotated relative to the sleeve 4.

[0090] In Fig. 8C A cross-section through the second embodiment of the force transmission element 1 in the area of ​​the flat embossings 6.1, 6.2, 6.3, 6.4 is schematically shown. The flat embossings 6.1-6.4 engage in the respective recesses 5.1-5.4 and rest against the electrical insulation 3. The flat embossings 6.1-6.4 can be formed, for example, by embossing with one or more dies. The recesses can be formed, for example, by milling.

[0091] A locking element engaging in one of the flat impressions 6.1, 6.2, 6.3, 6.4 with a flat surface facing the impression blocks the rotational degree of freedom of the sleeve 4, but not of the rod 2, relative to the tubular shaft.

[0092] In the Figs. 9 und 10 A fourth embodiment of the force transmission element 1 is shown schematically.

[0093] The recess in the rod 2 is circular and has only a proximal stop of the recess 5. The recess tapers off at a predetermined angle relative to the axial direction in the distal direction. For example, the recess 5 in the rod 2 can be created by turning.

[0094] The electrical insulation 3 lies circularly and concentrically on the rod 2 also in the area of ​​the recess 5.

[0095] The embossing 6 in the sleeve 4 is circular with only one proximal stop 7B and can be formed, for example, by roll embossing with one or more rotating rollers which are tilted by a corresponding angle with respect to the axial direction.

[0096] In Fig. 10 A longitudinal section through the fourth embodiment of the force transmission element 1 is shown schematically. The sleeve 4 has an embossed portion 6 that engages the entire recess 5, with the sleeve 4 resting against the electrical insulation 3. The proximal stop 7B of the sleeve 4 rests against the proximal stop 8B of the rod 2 or the insulation 3 in this area. The degree of freedom in the axial direction of the rod 2 relative to the sleeve 4 is thus limited, at least in the distal direction. Depending on the sliding properties between the electrical insulation 3 and the sleeve 4, the rod 2 with the insulation 3 can be rotated relative to the sleeve 4.

[0097] In Fig. 11 is an embodiment of the method for producing the force transmission element for surgical instruments, in particular a force transmission element 1 from the Fig. 2 bis 10, shown schematically. The method comprises the steps of providing S1, applying S2, circumferentially arranging S3, and embossing S3.

[0098] In the provision step S1, an electrically conductive rod configured for force transmission is provided, which has a recess. The provision step S1 includes the substep creation S1.2.

[0099] In the creation step S1.2, the recess is created in the rod. The recess is created, in particular, by forming, for example, pressing, or by machining, for example, milling or turning. Only one (proximal or distal) stop of the recess can be created, optionally in the (distal or proximal) tapered recess, or two stops (a proximal and a distal stop) can be created.

[0100] In the application step S2, electrical insulation is applied circumferentially, preferably circularly and particularly preferably concentrically, over an outer surface and at least partially in the axial direction along the rod such that the insulation extends at least along the recess. In particular, the application step S2 comprises shrinking a shrink tube (e.g., made of PTFE) onto the rod or coating the rod (e.g., with a polymeric or ceramic material).

[0101] In the circumferential arrangement step S3, an electrically conductive sleeve is arranged around the insulation, at least in sections, in the axial direction along the electrical insulation, preferably circularly and particularly preferably concentrically. The circumferential arrangement step S3 comprises the substeps heating S3.1, sliding S3.2, and cooling S3.3.

[0102] In the heating step S3.1, the sleeve is heated until an inner diameter of the sleeve is larger than an outer diameter of the electrical insulation due to thermal expansion.

[0103] In the sliding-on step S3.2, the heated sleeve is pushed onto the electrical insulation. The sleeve is pushed on (in the axial direction) until it is positioned at least in one area above the recess.

[0104] In the cooling step S3.3, the heated and pushed-on sleeve is cooled. This can be achieved, for example, by thermal radiation or convection against still or moving ambient air, or by quenching with a cooling medium.

[0105] In the embossing step S4, an embossed pattern is embossed into the sleeve, engaging at least partially into the recess and designed to engage with a securing element of a surgical instrument. The embossed pattern can be embossed into the sleeve by roller embossing with one or more embossing rollers parallel to the axial direction or tilted relative to it, or by embossing with one or more punches acting on the sleeve in a radial direction. LIST OF REFERENCE SYMBOLS

[0106] 1Force transmission element 2Rod 3Electrical insulation 4Sleeve 5Recess 5.1-5.4Individual recesses 6Embossing 6ASubstantially flat section 6.1-6.4Flat embossing 7A-7BEmbossed stop 8A-8BEmbossed stop 10Surgical instrument 11Tubular shaft 12Securing element 12ASurface facing the embossing 13Tool / accessory 14Handle 15Movable handle shank 16Accessory interface 17Annular spring

Claims

1. A force transmission element (1) for surgical instruments, with: an electrically conductive rod (2) designed for force transmission; an electrical insulation (3), which extends circumferentially over an outer surface and at least in sections in the axial direction along the rod (2); and an electrically conductive sleeve (4), which is arranged circumferentially around the electrical insulation (3) and extends at least in sections in the axial direction along the electrical insulation (3), wherein the rod has at least one recess (5) and the insulation (3) extends at least along the recess (5), and wherein the sleeve (4) has an embossment (6), which extends at least in sections into the recess (5) and which is designed to engage with a securing element (12) of a surgical instrument (10).

2. The force transmission element (1) according to claim 1, characterised in that the rod (2) is designed as a round rod, wherein the electrical insulation (3) extends at least in sections circularly along the surface of the rod (2), and wherein the sleeve (4) is designed as a round tube and extends at least in sections circularly along the surface of the electrical insulation (3).

3. The force transmission element (1) according to one of the preceding claims, characterised in that the embossment (6) is designed to block at least the rotational degree of freedom about an axis parallel to the axial direction of the sleeve (4) upon engagement of a securing element (12).

4. The force transmission element (1) according to claim 3, characterised in that the embossment (6) has at least one substantially flat section (6A) for making substantially planar-lying contact with a flat surface (12A) of a securing element (12), which runs parallel to the axial direction of the sleeve (4) and lies radially further inwards with respect to the outer surface of the sleeve (4).

5. The force transmission element (1) according to claim 4, characterised in that the recess (5) has at least one substantially flat section (5A) parallel to the axial direction of the rod (2), which lies further inwards in the radial direction with respect to the outer surface of the rod (2) and is contacted with the substantially flat section (6A) of the embossment (6) so as to lie, in particular lie planar, on one another.

6. The force transmission element (1) according to one of the preceding claims, characterised in that the embossment (6) is designed for limiting or blocking at least the translational degree of freedom in a direction parallel to the sleeve (4) upon engagement of a securing element (12), wherein the embossment (6) has in particular at least one stop (7A, 7B) for blocking or limiting at least the translational degree of freedom.

7. The force transmission element (1) according to one of the preceding claims, characterised in that the recess (5) has at least one stop (8A, 8B) which is designed to limit or block at least the translational degree of freedom in a direction parallel to the rod (2) together with the embossment (6).

8. The force transmission element (1) according to one of the preceding claims, characterised in that the electrical insulation (3) has sliding properties on its outer surface at least in the region of the embossment (6) and / or the sleeve (4) has sliding properties on its inner surface at least in the region of the embossment (6).

9. A surgical instrument (10), with: a force transmission element (1) according to one of the preceding claims; a tubular shaft (11) in which the force transmission element (1) is received; a securing element (12), which is supported in the tubular shaft (11) and which engages into the embossment (6) of the sleeve (4) of the force transmission element (1); a tool (13) which is movable by means of the force transmission element (1); and an actuating interface which is designed to actuate the force transmission element.

10. The surgical instrument (10) according to claim 9, characterised in that the tubular shaft (11) is designed as a round tube, wherein the rod (2) of the force transmission element (1) is designed as a round rod and the electrical insulation (3) extends at least in sections circularly along the surface of the rod (2), wherein the sleeve (4) is designed as a round tube and extends at least in sections circularly along the surface of the electrical insulation (3), and wherein the force transmission element (1) is arranged concentrically in the tubular shaft (11).

11. The surgical instrument (10) according to claim 9 or 10, characterised in that the securing element (11) has sliding properties on its surface facing the embossment (6) and / or the embossment (6) has sliding properties on its outer surface.

12. A method for manufacturing a force transmission element (1) for surgical instruments, in particular a force transmission element (1) according to one of claims 1 to 7, comprising the following steps: providing (S1) an electrically conductive rod (2) which is designed for force transmission and which has a recess (5); applying (S2) an electrical insulation (3) circumferentially over an outer surface and at least in sections in the axial direction along the rod (2) such that the insulation (3) extends at least along the recess (5); circumferentially arranging (S3) an electrically conductive sleeve (4) around the insulation (3) at least in sections in the axial direction along the electrical insulation (3); and impressing (S4) into the sleeve (4) an embossment (6) which engages at least in sections into the recess (5) and which is designed to engage with a securing element (12) of a surgical instrument (10).

13. The method according to claim 12, characterised in that providing (S1) comprises a step of creating (S1.2) the recess (5) in the rod (2), in particular by reshaping or machining.

14. The method according to claim 12 or 13, characterised in that applying (S2) the insulation (3) comprises shrinking a shrink tube onto the rod (2) or coating the rod (2).

15. The method according to one of claims 12 to 14, characterised in that the step of circumferentially arranging (S3) comprises the following steps: heating (S3.1) the sleeve (4) until, due to thermal expansion, an inner diameter of the sleeve (4) is larger than an outer diameter of the electrical insulation (3); sliding (S3.2) the heated sleeve (4) onto the electrical insulation (3); and cooling (S3.3) the heated sleeve (4) that has been pushed on.