Instrument shaft for an electrosurgical instrument and associated electrosurgical instrument

Abstract

Main claim: An instrument shaft (60) for an electrosurgical instrument (48), wherein the instrument shaft (60) can be rotatably attached to a handle (46) or an actuator unit and has a shaft tube (40) to which at least one slip ring (2) is fixed in order to form an electrical connection, comprising an electrically conductive ring body (4) from which an electrically conductive contacting element (12) for electrically connecting a connection line comprising a strand / wire and an insulating sheath laterally protrudes at one point along the circumference of the ring body, wherein the contacting element (12) comprises at least one cutting / clamping element (26) which has a cutting profile (22) and a contacting profile (24) and which is designed in such a way that, when inserting or pushing in the connection line, same is initially stripped by the cutting profile (22) and then the exposed strand / wire electrically contacts the contacting profile (24) and is held in same by clamping.

Description

[0001] Description

[0002] Instrument shaft for an electrosurgical instrument and associated electrosurgical instrument

[0003] The invention relates to an instrument shaft for an electrosurgical instrument. It further relates to an electrosurgical instrument having such an instrument shaft.

[0004] In numerous applications, particularly in the field of surgical instruments, reliable electrical contact is essential. One object of the present invention is to provide a slip ring that enables a secure electrical connection between a fixed shaft and a rotating component, particularly in applications such as electrosurgical instruments. Among other things, the invention aims to provide an efficient solution in which a connecting cable, particularly for an electrode of an electrosurgical instrument, is easily electrically connected during the assembly process.

[0005] The object is achieved according to the invention by an instrument shaft for an electrosurgical instrument having the features of claim 1. A corresponding electrosurgical instrument or tool is defined in claim 14.

[0006] Accordingly, as a component of an instrument shaft or shaft for short, which can be rotatably attached to a handle or an actuator unit, a slip ring is provided for forming an electrical connection between the shaft and a component which is rotatably mounted relative to the shaft, said slip ring comprising an electrically conductive ring body from which an electrically conductive contacting element for electrically connecting a connecting line comprising a stranded wire / a wire and an insulating sleeve protrudes laterally at one point on its circumference, wherein the contacting element comprises at least one insulation displacement element with a cutting geometry and a contacting geometry which is designed such that when the connecting line is inserted or pressed in, said element is first stripped of insulation by the cutting geometry and then the exposed stranded wire / wire electrically contacts the contacting geometry and is held in place therein by clamping.

[0007] The integration of an insulation displacement unit in the slip ring not only enables automatic stripping of the connecting cable during insertion, but also ensures reliable electrical contact and clamping. Furthermore, the invention aims to create a stable mechanical connection between the slip ring and an insulation ring to ensure precise, electrically insulated positioning of the slip ring.

[0008] In an advantageous embodiment, the cutting geometry comprises a V-shaped notch in a panel or between two posts, with the edges of the V-shaped notch forming cutting edges. The V-shaped notch enables precise stripping of the insulating sheath of the connecting cable. The clear cutting geometry minimizes the risk of damage to the cables (strands) during the stripping process. This promotes a low error rate.

[0009] Furthermore, the contact geometry advantageously includes a channel-like or linear notch as an extension of the V-shaped notch, with the edges of the channel-like or linear notch forming contact and clamping surfaces. The channel-like or linear notch ensures secure electrical contact and clamping of the stranded wire. The clear structure of the contact and clamping surfaces optimizes signal transmission efficiency.

[0010] In a preferred embodiment, several insulation displacement elements are arranged one behind the other on a common base plate. This enables redundant contacting of the stranded wire at several locations without complicating the pressing-in of the connecting cable.

[0011] Furthermore, it is advantageous if the contacting element comprises at least one holder arm that can be bent manually or by means of a tool to mechanically secure an inserted connecting cable. The clamping of the connecting cable, which is already present due to the contact geometry, is thus supported by positive locking.

[0012] Advantageously, at least one connecting element protrudes laterally from the ring body for connection to an associated, electrically insulating insulation ring. This laterally protruding connecting element facilitates the mounting of the slip ring on the insulation ring and enables a compact design of the overall system.

[0013] In a preferred embodiment, the connecting element is designed to form a snap-in or locking connection. The snap-in or locking connection enables quick and secure assembly of the slip ring to the insulation ring (and subsequent disassembly, if necessary).

[0014] Furthermore, it is preferred that the respective connecting element be arranged on a side of the annular body facing away from the contacting element. This facing-away arrangement minimizes undesirable interference between the contacting element and the connecting element.

[0015] In an advantageous embodiment, the slip ring, including the contact element and, if present, the connecting element, is formed as a single piece, particularly as a cast part. The single-piece design of the slip ring, particularly as a cast part, reduces manufacturing costs and ensures a robust structure.

[0016] It is advantageous for the ring body to have a continuous, preferably uninterrupted, outer surface as a sliding contact surface. This continuous outer surface ensures a uniform and reliable transmission of electrical voltage over a 360° rotation.

[0017] The invention further teaches an electrical contact between a shaft and a component mounted rotatably relative to the shaft, comprising a slip ring of the type described above that is mechanically connected to an insulating ring. The insulating ring is firmly fixed to the shaft and electrically insulates the slip ring from the shaft. As already mentioned, the slip ring can be connected to the insulating ring, in particular by means of a snap-in or locking connection.

[0018] Advantageously, a spring contact pin is provided for tapping an electrical voltage from the slip ring. This enables reliable, continuous electrical contact.

[0019] Alternatively or in addition to the insulation displacement connection, a crimp connection or crimp geometry can be integrated into the contacting element of the slip ring. A crimp connection is an electrical connection technique in which a metal piece (typically a crimp contact or crimp plug) is pressed onto a cable end to create a secure electrical connection. This is usually done using a crimping tool, which permanently presses the metal piece onto the cable by deforming or compressing it. The function of the crimping tool is preferably integrated into the contacting element.

[0020] Finally, the invention teaches a surgical tool with a handle part and a component that can be rotated relative to the handle part, wherein the component is electrically connected to the handle part via an electrical contact of the type described above.

[0021] In one possible embodiment, the component is a gripper having at least one voltage-sensitive electrode. The advantages achieved by the invention are summarized in particular in that the slip ring presented here ensures high efficiency and reliability in the electrical connection between the fixed shaft and the rotatably mounted component. The integration of an insulation displacement element enables effective stripping and contacting of the connecting cable without prior complex preparation. This not only simplifies the assembly process but also significantly reduces manufacturing costs.

[0022] The mechanical connection between the slip ring and the insulation ring, particularly through a snap-in or locking connection, ensures stable positioning and prevents unwanted axial or rotational movements during operation. This is crucial in applications such as surgical instruments, where precise electrical connections are essential for functionality and safety.

[0023] Furthermore, the design of the slip ring with a circumferential, preferably uninterrupted outer surface as a sliding contact surface enables a uniform and reliable transmission of electrical voltage over a full 360° rotation.

[0024] Various embodiments of the invention are explained in more detail below with reference to the accompanying drawings. Each schematically shows:

[0025] FIG. 1 shows a perspective view of a slip ring for forming an electrical contact between components movable relative to one another, in particular between a shaft and a handle of an electrosurgical instrument,

[0026] FIG. 2 shows a further perspective view of a slip ring, FIG. 3 shows the slip ring from FIG. 2 with a connected electrical line,

[0027] FIG. 4 is a perspective view of a slip ring-insulation ring assembly,

[0028] FIG.5 is a further perspective view of a slip ring-insulation ring assembly,

[0029] FIG. 6 shows an instrument shaft of an electrosurgical instrument, wherein a slip ring-insulation ring assembly is mounted on a shaft tube,

[0030] FIG. 7 shows a cross-section through the instrument shaft of FIG. 6 in the area of ​​the slip ring-insulation ring assembly, and

[0031] FIG. 8 shows an overview of an electrosurgical instrument.

[0032] Identical or equivalent elements are provided with the same reference numerals in all figures.

[0033] The slip ring 2 shown in perspective view in FIGS. 1 and 2 serves to establish an electrical connection between a shaft and a component rotatably arranged on / upon or relative to the shaft, in particular a handle, especially of a surgical instrument.

[0034] The slip ring 2 comprises an electrically conductive ring body 4, in particular made of an electrically conductive metallic material.

[0035] The annular body 4 has an outer surface 6, which is preferably flat in cross-section, and an inner surface 8. Between the outer surface 6 and the inner surface 8 lies an annular end face 10 (one on each side). The outer surface 6 forms a sliding contact surface, or grinding surface for short, over its entire circumference for electrical contact by a grinding element of an associated component that can rotate relative to the slip ring 2.

[0036] At one point on the circumference, a contact element 12 is formed on the ring body 4, protruding laterally from it. The contact element 12 serves to electrically connect an electrical connection cable to the slip ring 2.

[0037] At one point on the circumference, at least one connecting element 14 is formed on the annular body 4, projecting laterally therefrom. The connecting element 14 serves to permanently mechanically connect the slip ring 2 to an associated insulation ring 16 (see also FIGS. 4 and 5). Several such connecting elements 14 can also be distributed over the circumference of the slip ring 2.

[0038] The connecting element 14 is preferably designed to form a (releasable) snap connection with a counterpart of the insulating ring 16. For this purpose, the connecting element 14 can have a locking opening / snap opening or a locking lug / snap lug, or generally speaking, a locking element 18 or snap element.

[0039] FIG. 1 shows a variant with a snap-in opening. Alternatively, a snap-in nose can be provided. As mentioned above, all of these variants can be summarized under the generic term "locking element / snap-in element." The corresponding insulation ring 2 is equipped with a functionally complementary counterpart.

[0040] The connecting element 20 nestles essentially tangentially against the ring body 4 in the manner of a lateral projection.

[0041] The contacting element 12 and the connecting element 14 are preferably arranged facing away from each other on different sides of the annular body 2. This means that the contacting element 12 is connected to one end face 10, and the connecting element 14 is connected to the other end face 10.

[0042] In the example, the contacting element 12 and a first connecting element 14 are arranged at the same location on the circumference of the annular body 4. Furthermore, purely by way of example, a second connecting element 14 is present at a different circumferential location, here at a 90° position relative to the first connecting element 14.

[0043] The ring body 4, the contacting element 12 and the connecting element 14 together form an integral (one-piece), electrically conductive body, namely the slip ring 2.

[0044] The contacting element 12 has an integrated insulation displacement unit 20, which is designed to create an electrical connection when inserting or pressing in an electrical connecting cable.

[0045] The connecting cable 44 (shown in FIGS. 3 and 7) typically comprises a stranded wire (a wire braid composed of individual strands) with an electrically insulating sheath or insulation. Instead of a stranded wire, a single wire or conductor may also be present.

[0046] The insulation displacement unit 20 comprises a cutting geometry 22 which strips the connecting cable 44 at the contact point when it is pressed in, i.e. removes the insulating sheath and exposes the stranded wire.

[0047] Furthermore, the insulation displacement unit 20 comprises a contact geometry 24, which electrically contacts and clamps the stripped stranded wire during further pressing.

[0048] Specifically, in the exemplary embodiment, the insulation displacement unit 20 comprises at least one substantially U-shaped insulation displacement element 26. At the open U-end, the two U-legs or posts 28 of the insulation displacement element 26 each have a cutting edge 30 running obliquely to the longitudinal direction of the post 28, so that overall a V-shaped cutting geometry 22 with a pair of cutting edges is realized, which strips the insulation of the connecting cable 44 when it is pressed in.

[0049] At the widest (outermost) point, the V-shaped incision 32 is at least as wide as the outer diameter of the insulating sheath of the connecting cable in order to be able to strip it reliably.

[0050] The cutting edges 30 can be single-sided, double-sided, or not ground at all. The cutting edges 30 preferably have sharpened cutting edges.

[0051] Toward the closed U-shaped end, the V-shaped notch 32 of the cutting geometry 22 continues into a linear notch 34 of constant width (approximately corresponding to the strand diameter or slightly smaller), which forms the aforementioned contact geometry 24. In the final contacting position, the stranded wire stripped in this section sits / lies in the linear notch 34. The V-shaped notch 32 and the linear notch 34 together form a funnel-shaped notch.

[0052] For a particularly secure electrical contact of the connecting cable at several points, several, here two in the example, of the insulation displacement elements 26 can be arranged one behind the other, preferably in congruent alignment.

[0053] Between and / or next to the insulation displacement elements 26, at least one holding arm 36 is advantageously arranged, which in the initial state is aligned in the direction of the U-legs or posts 28.

[0054] The material thickness is dimensioned such that the retaining arm 36 can be bent over the connecting cable after it has been pressed in, mechanically securing it in the final contact position. In other words, by reshaping at least one retaining arm 36, the connecting cable is fixed in its position, thus preventing accidental withdrawal under tensile stress.

[0055] In the example shown in FIGS. 1 and 2, two holding arms 36, which can be bent in opposite directions to each other, are arranged between the two insulation displacement elements 26. The two holding arms 36 are offset from each other so that they do not interfere with each other during bending.

[0056] Conveniently, the posts 28 of the insulation displacement elements 26 and the holding arms 36 are arranged on a common base plate 38 which projects laterally from the ring body 4.

[0057] The posts 28 of the insulation displacement elements 26 and, if present, the retaining arms 36 (in the non-bent initial state) preferably project radially outward with respect to the basic ring geometry, while the base plate 38 fits tangentially against the ring body 4. This means that the connecting cable is preferably connected to the contacting element 12 of the slip ring 4 from the outside.

[0058] In summary, the connecting cable 44, consisting of stranded wire (wire mesh) and insulating sheath, is inserted between the cutting edges 30 of the V-shaped cutting geometry 22 and pressed downwards using a tool or manually. This splits the insulating sheath in this area, exposing the stranded wire or wire core.

[0059] By further pushing or pressing in the connecting cable 44, the wires are placed on the contact and clamping surfaces 42 of the contact geometry 24, whereby the stranded wire is reliably electrically connected to the slip ring 2.

[0060] A key advantage of the insulation displacement geometry is that the connecting cable 44 used does not need to be separately stripped beforehand. By integrating the insulation displacement geometry directly into the slip ring 2, manufacturing costs can be significantly reduced.

[0061] As already mentioned, the slip ring 2 is fixed to the insulation ring 16 by means of the connecting element 20, as can be seen in FIGS. 4 and 5. The fixation is preferably achieved by means of a snap or locking connection. A suitable snap-in lug can be integrated into both the slip ring 2 and the insulation ring 16.

[0062] This fixation prevents both the axial and the rotational movement of the slip ring 2 relative to the insulation ring 16.

[0063] In a typical application, the insulation ring 16 may be firmly connected to a shaft or shaft tube 40 by means of a positive and / or clamping fit or otherwise, as shown in FIGS. 6 and 7.

[0064] To establish the desired electrical connection during assembly, the slip ring 2 is connected to the insulation ring 16 by the snap connection described above. In the final assembly position, the slip ring 2 is arranged concentrically to the shaft tube 40 and to the insulation ring 16 at a distance around the shaft tube 40. This means that there is an annular space between the shaft tube 40 and the slip ring 2, which is advantageously filled by a section of the insulation ring 16. The insulation ring 16 is located at least partially between the shaft tube 40 and the slip ring 2. On at least one side, the insulation ring 16 projects laterally and possibly also radially beyond the slip ring 2, where it forms an end stop for the slip ring 2 on the one hand and anchoring points for the snap connection on the other.

[0065] As a result, the slip ring 2 is firmly connected indirectly to the shaft tube 40 via the insulation ring 16, in such a way that the slip ring 2 is electrically insulated from the shaft tube 40. The connecting cable 44 is now electrically connected to the contacting element 12 and thus to the slip ring 2 as a whole in the manner described. When operating voltage is applied, this voltage can be tapped via the slip ring 2.

[0066] A component rotatably mounted on the shaft tube 40 taps off the operating voltage via a sliding element that slides along the outer surface 6 of the annular body 4. The sliding element can, for example, comprise a spring-loaded contact pin. The sliding element is connected to other elements of an electrical circuit via a conductor. In this way, a voltage / current is typically transferred from the stationary to the rotating subsystem.

[0067] A first preferred manufacturing method for the slip ring 2 is a casting process. This means that the slip ring 2, including the contact element 12 and the connecting element 14, is cast as a whole in a mold.

[0068] In an alternative variant, the slip ring 2 is manufactured by laser cutting or other cutting from a ring blank or a lateral surface, with the blank subsequently being formed. This means that the parts of the contacting element 12 (posts 28 and retaining arms 36) that protrude radially outward in the final state are bent in the radial direction after cutting from the ring geometry.

[0069] In a preferred application, the slip ring 2 or the slip ring-insulation ring assembly 54 is part of the electrical contact between a shaft 40 and a component rotatable relative to the shaft 40, in particular a handle 46 of a surgical instrument 48.

[0070] In particular, the surgical instrument 48 can be a gripping and / or cutting tool, schematically illustrated in FIG. 8, with a rotatable gripper 50 equipped with electrodes 52 for performing a medical treatment (sclerotherapy, etc.). These electrodes 52 are supplied with high-frequency alternating voltage from a gripping part or handle 46 via an electrical contact of the type described. Such instruments are also called seal & cut instruments in view of their preferred intended use. If the two electrodes 52 are electrically insulated from each other and supplied with voltage separately, they are referred to as bipolar instruments.

[0071] In this respect, the invention also relates to an instrument shaft for an electrosurgical instrument 48 of the type shown by way of example in FIG. 8, in which, according to FIG. 6, the slip ring-insulation ring assembly 54 is firmly connected to the shaft tube 40, and in which at least one electrical line, namely the connecting line 44, is guided to the slip ring 2 via a recess 56 in the outer surface of the shaft tube 44, as indicated in FIGS. 6 and 7. The slip ring 2 is electrically insulated from the shaft tube 40 by means of the insulation ring 16, since this usually (i.e. in the case of bipolar instruments) forms the second electrical supply line to the jaw part or gripper 50 of the instrument. The shaft is rotatable relative to the handle 46 - or in the case of a robotically guided instrument shaft relative to the actuator unit - in this example by 360° or more.

[0072] The slip ring 2 is preferably arranged distal to the recess 56 in / on the outer surface of the shaft tube 40 in order to enable a more compact design without having to bend the electrical connecting cable 44 excessively. For the same reason, the slip ring 2 preferably covers the distal region of the recess 56. This allows the connecting cable 44 to run slightly "outwards" before it emerges through the remaining hole. This is particularly clearly visible in FIGS. 6 and 7. In FIG. 7, it only appears as if the connecting cable 44 runs forward, out of the image plane, toward the viewer. This is a representational problem, because the connecting cable 44 actually runs away from the viewer into the drawing sheet. In this representation, the viewer views the instrument shaft from a proximal position; the distal end of the shaft with the working section is therefore "at the back".

[0073] For a surgical instrument with a handle 46 and grasper 50, the terms "distal" and "proximal" refer to the direction relative to the patient's body. The distal end is the end of the instrument farthest from the patient's body, while the proximal end is the end closest to the patient's body. Typically, the handle 46 is considered the proximal end, while the grasper 50 or the working component is considered the distal end.

[0074] As mentioned, a primary application of the invention is bipolar seal-and-cut instruments. In principle, however, the described electrical contacting can also be used for other monopolar or bipolar electrosurgical instruments. It is particularly advantageous for endoscopic instruments (i.e., tubular-shaft instruments).

[0075] List of reference symbols

[0076] 2 slip ring

[0077] 4 ring bodies

[0078] 6 Exterior surface

[0079] 8 inner surface

[0080] 10 Frontal surface

[0081] 12 Contacting element

[0082] 14 Connecting element

[0083] 16 Insulation ring

[0084] 18 locking element

[0085] 20 insulation displacement unit

[0086] 22 Cutting geometry

[0087] 24 Contact geometry

[0088] 26 insulation displacement element

[0089] 28 posts

[0090] 30 cutting edges

[0091] 32 V-shaped incision

[0092] 34 straight incision

[0093] 36 Holding arm

[0094] 38 base plate

[0095] 40 shaft / shaft tube

[0096] 42 Contact and clamping surface

[0097] 44 connecting cable

[0098] 46 Handle

[0099] 48 (electro-) surgical instrument

[0100] 50 grippers

[0101] 52 Electrode

[0102] 54 Slip ring-insulation ring assembly

[0103] 56 recess

[0104] 60 instrument shaft

Claims

Claims 1. An instrument shaft (60) for an electrosurgical instrument (48), wherein the instrument shaft (60) is rotatably attachable to a handle (46) or an actuator unit and has a shaft tube (40) to which at least one slip ring (2) is fixed to form an electrical connection, comprising an electrically conductive annular body (4), from which an electrically conductive contacting element (12) protrudes laterally at one point on its circumference for electrically connecting a connecting cable comprising a stranded wire / a wire and an insulating sheath, wherein the contacting element (12) comprises at least one insulation displacement element (26) with a cutting geometry (22) and a contacting geometry (24), which is designed such that when the connecting cable is inserted or pressed in, the latter is first stripped of its insulation by the cutting geometry (22).and then the exposed strand / wire electrically contacts the contact geometry (24) and is held in place by clamping., 2. Instrument shaft (60) according to claim 1, wherein the cutting geometry (22) comprises a V-shaped incision (32) in a plate or between two posts (28), and wherein the edges of the V-shaped incision (32) form cutting edges (30).

3. Instrument shaft (60) according to claim 1 or 2, wherein the contacting geometry (24) comprises a channel-like or straight-line incision (34) as an extension of the V-shaped incision (32), and wherein the edges of the channel-like or straight-line incision (34) form contact and clamping surfaces (42).

4. Instrument shaft (60) according to one of the preceding claims, wherein several insulation displacement elements (26) are arranged one behind the other on a common base plate (38).

5. Instrument shaft (60) according to one of the preceding claims, wherein the contacting element (12) comprises at least one holder arm (36) which is mechanical fixation of an inserted connecting cable can be bent manually or using a tool.

6. Instrument shaft (60) according to one of the preceding claims, wherein at least one connecting element (14) protrudes laterally from the ring body (4) for connection to an associated, electrically insulating insulation ring (16).

7. Instrument shaft (60) according to claim 6, wherein the connecting element (14) is designed to form a snap or locking connection.

8. Instrument shaft (60) according to claim 6 or 7, wherein the respective connecting element (14) is arranged on a side of the annular body (4) facing away from the contacting element (12).

9. Instrument shaft (60) according to one of the preceding claims, wherein the slip ring (2) including the contacting element (12) and, if present, the connecting element (14) is formed in one piece, in particular as a cast part.

10. Instrument shaft (60) according to one of the preceding claims, wherein the annular body (4) has a circumferential, preferably uninterrupted outer surface (6) as a sliding contact surface.

11. Instrument shaft (60) according to one of the preceding claims, comprising an insulating ring (16) mechanically connected to the slip ring (2), wherein the insulating ring (16) is firmly fixed to the shaft tube (40) and electrically insulates the slip ring (2) from the shaft tube (40).

12. Instrument shaft (60) according to one of the preceding claims, wherein the slip ring (2) is connected to the insulation ring (16) by means of a snap or locking connection.

13. Instrument shaft (60) according to one of the preceding claims, wherein a spring contact pin is provided for tapping an electrical voltage from the slip ring.

14. Electrosurgical instrument (48) with a handle part or an actuator unit, and with an instrument shaft (60) rotatable relative to the handle part or the actuator unit according to one of the preceding claims.

15. Electrosurgical instrument (48) according to claim 14, which comprises a gripper (50) which has at least one electrode (52) which can be supplied with voltage via the slip ring (2).

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