Tool for a medical instrument

A tool for a distal end or on a distal end of a shaft of a medical instrument includes a basic body, a mouth part which is pivotable about a pivot axis in relation to the basic body, and a bearing which defines the pivot axis, wherein the bearing includes two axle journals which are spaced apart from one another, each with a radial surface which is rotationally symmetrical with respect to the pivot axis.

FIELD OF THE INVENTION

The present invention relates to a tool for a distal end or on a distal end of a shaft of a medical instrument and to a medical instrument having such a tool.

BACKGROUND OF THE INVENTION

Medical devices and medical personnel prefer medical instruments which can be used as variously as possible. The more variously the individual medical instrument can be used, the smaller the variety of instruments to be held in readiness. Variously usable medical instruments, consequently, can reduce the investment costs necessary in a medical setup even where unit costs are high. A small variety and a smaller number of medical instruments to be kept in readiness can also reduce costs for storage and logistics.

In the case of micro-invasive medical instruments or medical instruments for micro-invasive interventions, there is also the fact that during an intervention the less often instruments have to be changed, the more variously the individual instrument can be used.

SUMMARY OF THE INVENTION

An object of the present invention is to create an improved tool for a distal end or on a distal end of a medical instrument and an improved medical instrument. An object, in particular, is, in the case of a tool with a pivotable mouth part, to make possible an operating channel in which a scalpel or another acting element is able to be arranged and moved.

This object is achieved by the objects of the independent claims.

Further developments are provided in the dependent claims.

A tool for a distal end or on a distal end of a shaft of a medical instrument includes a basic body, a mouth part which is pivotable about a pivot axis in relation to the basic body, and a bearing which defines the pivot axis, wherein the bearing includes two axle journals which are spaced apart from one another, each with a radial surface which is rotationally symmetrical with respect to the pivot axis.

The tool is realized for (in particular detachable) mechanical coupling with the distal end of a shaft or is mechanically connected (in particular so as to be detachable without damage) to the distal end of a shaft. In this case, the shaft is a component part of a medical instrument or is provided for forming a medical instrument.

At the proximal end or in a proximal region, the basic body has a coupling for the detachable mechanical coupling with a distal end of a shaft. As an alternative to this, the basic body is mechanically connected to the distal end of a shaft in a permanent manner and so as to be detachable without damage. The tool can have a further mouth part which is not movable in relation to the basic body. Said further mouth part is connected in particular to the basic body in a rigid manner or is realized integrally with said basic body. As an alternative to this or in addition to it, the tool can have one or several further movable, in particular pivotable, mouth parts.

The bearing can include more than two axle journals which are spaced apart from one another, each having a radial surface which is rotationally symmetrical with respect to the pivot axis of the mouth part. Each individual axle journal is connected in a rigid manner either to the pivotable mouth part or to the basic body.

As described below and as is shown in detail by way of the exemplary embodiments, the two (or more) axle journals, which are spaced apart from one another, create new structural degrees of freedom.

A tool, as is described here, additionally includes, in particular, an operating channel in which a scalpel or another acting element can be displaced between a proximal and a distal position.

The scalpel is provided and realized, in particular, for cutting through tissue which is grasped by means of the tool. For example, the tool is realized for the monopolar or bipolar electro-cauterization of tissue grasped by means of the tool. A vessel or other tissue can be grasped, squeezed, scelerosed electro-surgically or HF-surgically by means of the tool and then cut through by means of the scalpel. The ability to carry out all of said procedure steps using one single tool can clearly reduce the time taken for a micro-surgical intervention. Instead of for a scalpel, the operating channel can be usable for other working elements which can be inserted with the tool in an open and/or a closed position.

In the case of a tool with an operating channel, as is described here, the operating channel is arranged, in particular, between the axle journals.

The operating channel extends, in particular, from a handling device along a shaft as far as up to the tool and to the active region of the pivotable mouth part. An arrangement of the operating channel between the axle journals means that the operating channel leads through between the axle journals or at least part of the lumen of the operating channel lies between the axle journals.

In the case of an almost arbitrary arrangement of the pivot axis of the pivotable mouth part, the bearing with two (or more) axle journals, which are spaced apart from one another, makes possible a large cross section or a large lumen of the operating channel, at least in the direction at right angles with respect to the longitudinal axis of the tool and at right angles with respect to the pivot axis. Comparable cross sections of the operating channel are possible in the case of a bearing with a continuous shaft at most where the shaft is arranged at a large spacing from the center of the cross section and there is a small spacing between the shaft and the outer edge of the cross section of the tool. However, said arrangement of the shaft is only possible with a circular cross section of the tool if the shaft is short, which results in other structural disadvantages.

In the case of a tool, as is described here, the basic body of the tool includes, in particular, two parallel walls, between which a portion of the operating channel is arranged, wherein each of the two parallel walls has a recess in which one of the two axle journals engages.

The two parallel walls are realized, in particular, as webs on a base plate.

The two (or more) parallel walls are arranged, in particular, parallel with respect to the longitudinal axis of the tool or of a shaft which is connected to the tool or is to be connected to the tool and at right angles with respect to the pivot axis of the pivotable mouth part. The two parallel walls define, in particular, the operating channel on two opposite sides such that the operating channel is defined at least in portions by the two opposite walls. Each recess is formed, in particular, by a blind hole in one of the two parallel walls. As an alternative to this, the two recesses are formed by one single through-bore which penetrates the two parallel walls.

In the case of a tool, as is described here, the bearing includes additionally, in particular, recesses which correspond to the axle journals, wherein the axial pins engage in the recesses from the outside.

As already mentioned for the embodiment with two parallel walls, in other cases the recesses which correspond to the axle journals can also be formed by one single through-bore, the axle journals engaging in the two opposite ends of the through-bore. The term engage from the outside refers to an engagement from two opposite directions where the axle journals project toward one another.

In the case of a tool, as is described here, the bearing additionally, in particular, includes recesses which correspond to the axle journals, wherein the axial pins engage in the recesses from the inside.

The phrase the axle journals engage in the recesses from the inside refers to the axle journals projecting in two opposite directions facing away from one another.

In the case of a tool, as is described here, the mouth part includes, in particular, two axle journal components each with one of the axle journals.

Each axle journal component is produced, in particular, in one piece. At the proximal end thereof, each axle journal component includes, in particular, the associated axle journal and an arm or bar which extends substantially at right angles with respect to the pivot axis of the pivotable mouth part. If the axle journal components are component parts of the pivotable mouth part, the arms or bars are connected, in particular, to the pivotable mouth part, are arranged in said mouth part or form the pivotable mouth part.

As an alternative to this, the arms or bars are connected in a rigid manner to the basic body of the tool, and the axle journals engage in recesses which are provided on the pivotable mouth part.

In the case of a tool with two axle journal components, as is described here, the axle journal components have been connected together in a rigid manner once the axle journals have been inserted into the corresponding recesses.

In particular, once the axle journals have been inserted in the corresponding recesses, the already mentioned arms or bars have been joined together directly or indirectly in order to form, for example, the pivotable mouth part.

In the case of a tool with axle journal components which have been connected together in a rigid manner once the axle journals have been inserted in the corresponding recesses, the axle journal components are connected together in a rigid manner, in particular, by means of a basic body of the pivotable mouth part.

In particular, the mentioned arms or bars of the axle journal components are inserted into bores or grooves in the basic body of the pivotable mouth part and are joined.

A tool, as is described here, includes additionally, in particular, a transferring device for transferring a force to the tool, wherein the transferring device and the pivotable mouth part have curved sliding faces which abut against one another and are realized for the purpose of coupling a translation movement of the transferring device with a pivoting movement of the pivotable mouth part, wherein a center of curvature of the curved sliding faces lies outside the tool.

The transferring device is slidable, in particular, lengthwise of a shaft which is couplable to the tool or is connected in a permanent manner. The transferring device can be coupled in such a manner with the mouth part by means of the curved sliding faces, which abut against one another, that a movement of the transferring device in the proximal direction brings about a closing pivoting movement of the mouth part or, as an alternative to this, in a reverse manner brings about an opening movement of the mouth part. The transferring device, in this case, is guided, in particular, inside the tool or inside a shaft which is couplable with the tool or is permanently connected to the tool, such that it is slidable along a substantially straight or slightly curved path.

The sliding faces of the transferring device and of the pivotable mouth part, in each case abutting against one another in pairs, have, in particular, a common center of curvature or are rotationally symmetrical with respect to an axis. Said substantially arcuate development of the sliding faces enables flat contact which can be suitable for transferring large forces.

As an alternative to this, the sliding faces can have several centers of curvature or a varying curvature or a development which is not rotationally symmetrical with respect to an axis. With said resultant non-arcuate development of the sliding faces, a varying transformation ratio can be realized between the movement of the transferring device and the pivoting movement of the pivotable mouth part.

The arrangement of the center of curvature of the curved sliding faces makes possible a large transformation ratio where a translation movement of the transferring device along a relatively long path is necessary for a predetermined pivoting movement of the pivotable mouth part.

In the case of a tool with curved sliding faces, abutting against one another, on the transferring device and the pivotable mouth part, as is described here, in particular the curved sliding faces on the mouth part are parallel faces on a curved groove and the curved sliding faces on the transferring device are parallel faces on a curved web. As an alternative to this, the curved sliding faces on the mouth part can be parallel faces on a curved web and the curved sliding faces on the transferring device can be parallel faces on a curved groove. As an alternative to this, the curved sliding faces can be non-parallel.

In the case of a tool, as is described here, the pivot axis about which the pivotably mounted mouth part is pivotable lies in particular inside the tool.

An arrangement of the pivot axis inside the tool refers to the fact that the pivot axis intersects or penetrates the volume assumed by the tool. In other words, a portion of the pivot axis lies inside the contour of the tool.

In the case of a tool, as is described here, a groove is provided inside a circular cylindrical region of space, in particular, on at least one of the two axle journals, wherein the radial surface of the axle journals lies on a radial surface of the circular cylindrical region of space.

Side walls of the groove lying opposite one another form, in particular, the mentioned curved sliding faces on the pivotable mouth part. In particular, a web on the mentioned transferring device engages in the groove.

A medical instrument includes a tool, as is described here.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1shows a schematic representation of a medical instrument10which is realized, in particular, for micro-invasive surgical interventions. At the proximal end11thereof, the medical instrument10includes a handling device15and at the distal end12thereof it includes a tool40. A straight or curved, rigid or flexible shaft20connects the handling device15and the tool40. The proximal end21of the shaft20is connected to the handling device15, the distal end22of the shaft20is connected to the tool40.

Two parts of the handling device15are movable in relation to one another. One of the two parts is connected in a rigid manner to the tool40by means of the shaft20, the other part of the handling device15is coupled with a pivotable mouth part42of the tool40by means of a transferring device (in particular a transferring rod) which is arranged in the shaft20. A manually activated relative movement of the two parts of the handling device15results in a corresponding relative movement of the pivotable mouth part42in relation to a fixed mouth part41of the tool40.

FIG. 2showed an enlarged schematic representation of a tool40which is similar to the tool shown above by way ofFIG. 1and is usable on medical instruments which are similar to that shown above by way ofFIG. 1.

The tool40is coupled mechanically with the distal end22of a shaft20so as to be detachable or is permanently connected thereto. The tool40includes a fixed mouth part41and a pivotable mouth part42. The fixed mouth part41is arranged in a rigid manner in relation to the shaft20. The pivotable mouth part42is pivotable in relation to the fixed mouth part41about a pivot axis48at right angles with respect to the drawing plane ofFIG. 2. The pivot axis48is defined by a bearing43which is arranged in the interior of the tool40and is indicated by the broken line inFIG. 2. A center of curvature38is described in more detail below with reference toFIGS. 12 and 13.

FIGS. 3 and 4show schematic axonometric representations of parts of the tool40fromFIG. 2. The tool40includes a basic body50with a base plate51with a step-shaped profiled edge. The base plate51extends substantially parallel with respect to the longitudinal axis of a shaft to be connected to the tool40and at right angles with respect to the drawing planes ofFIGS. 1 and 2. A first longitudinal web56and a second longitudinal web57are arranged at right angles with respect to the base plate51. The two longitudinal webs56,57extend parallel with respect to the longitudinal axis of a shaft to be connected to the tool40and parallel to the drawing planes ofFIGS. 1 and 2. Between the longitudinal webs56,57is provided a narrow operating channel58, which extends, as the longitudinal webs56,57, parallel with respect to the longitudinal axis28of a shaft to be connected to the tool40as far as up to the distal end of the basic body50. The two longitudinal webs56,57are connected by a connecting pin59close to the edges thereof which are at a spacing from the base plate51. The connecting pin59extends at right angles with respect to the longitudinal axis28of a shaft to be connected to the tool40and at right angles with respect to the drawing planes ofFIGS. 1 and 2.

A first axle journal component60and a second axle journal component70are realized in a mirror symmetrical manner with respect to one another and are connected to the basic body50so as to be pivotable. Features of the bearing arrangement of the axle journal components60,70on the basic body50are described in more detail below with reference toFIGS. 5 to 7. The axle journal components60,70, in particular a bar62of the first axle journal component60and a bar72of the second axle journal component70, are component parts of the pivotable mouth parts42shown inFIGS. 1 and 2.

A transferring device30extends in the shaft20(cf.FIG. 1) from the handling device15as far as up to the tool40. On the distal end, the transferring device30includes two parallel bars33,34which are realized in a mirror-symmetrical manner with respect to one another. Only the first bar33can be seen clearly inFIGS. 3 and 4, the second bar34is extensively covered. The bars33,34on the distal end of the transferring device30are arranged on both sides of the longitudinal webs56,57of the basic body50.

A sleeve45is arranged on the proximal end of the basic body50. The sleeve45, in the example shown, has cross section which varies in a step-shaped manner. The sleeve45surrounds the transferring device30or the bars33,34thereof in a ring-shaped manner. A coupling for the detachable mechanical coupling of the tool40with a distal end22of a shaft20(cf.FIGS. 1 and 2) is arranged on the proximal edge of the sleeve45.

Each bar33,34has a curved web which engages in a curved groove on one of the axle journal components60,70. Said webs on the bars33,34and the grooves on the axle journal components60,70cannot be seen inFIGS. 3 and 4, but will be described below with reference toFIGS. 5 to 7, 12 and 13. The engagement of the webs on the bars33,34in the grooves on the axle journal components60,70couples a translation movement of the transferring device30and a pivoting movement of the axle journal components60,70together.

FIG. 3shows the transferring device30in a distal position and the axle journal components60,70or the bars62,72thereof in open positions which correspond to the distal position of the transferring device30.FIG. 4shows the transferring device30in a proximal position and the axle journal components60,70or the bars thereof62,72in closed positions which correspond to the proximal position of the transferring device30.

FIG. 5shows a schematic axonometric representation of the basic body50and of the axle journal components60,70prior to insertion of the axle journal components60,70into the basic body50. The basic body50has a recess53in the form of a through-bore at right angles with respect to the longitudinal axis28(cf.FIGS. 1 to 4) and parallel with respect to the pivot axis48of the pivotable mouth part42(cf.FIG. 2). The through-bore53penetrates both longitudinal webs56,57of the basic body50. The first axle journal component60includes an axle journal63with a narrow ring-shaped radial surface64. The second axle journal component70includes an axle journal73with a narrow ring-shaped radial surface74.

The axle journals63,73can be inserted into the recess53on the basic body50by means of insertion movements61,71, indicated by means of arrows, parallel to the pivot axis48. The recess53has a circular cross section which is tuned in such a manner to the radial surfaces64,74of the axle journals63,73that the axial pins63,73, once they have been inserted61,71into the recess53, are guided on the basic body low in play and friction. The recess53in the basic body50and the axle journals63,73engaging in the recess53form the joint or bearing43which has already been indicated inFIG. 2and defines the pivot axis48of the pivotable mouth part42. The widths of the ring-shaped radial surfaces64,74of the axle journals63,73correspond substantially to the wall thicknesses of the longitudinal webs56,57on the basic body50.

FIG. 6shows a further schematic axonometric representation of the axle journal components60,70fromFIGS. 3 to 5. The axle journal components60,70are shown in the relative position and spaced apart as they are when the axle journals63,73of the axle journal components60,70are inserted fully into the recess53on the basic body50(cf.FIG. 5). The basic body50, however, is not shown inFIG. 6. The axle journals63,73or the circular end faces thereof are at a spacing which corresponds substantially to the width of the operating channel58between the longitudinal webs56,57on the basic body50(cf.FIGS. 3 to 5). In other words, the axle journals63,73do not engage in the operating channel58nor restrict the lumen or cross section thereof.

FIG. 7shows a schematic axonometric representation of the basic body50and of the axle journal components60,70. The axle journals63,73(cf.FIGS. 5 and 6) of the axle journal components60,70are inserted into the recess53(cf.FIG. 5) in the basic body50. In addition, the distal end of the transferring device30with the bars33,34is shown. The bars33,34, however, have not yet been inserted into the basic body50and coupled with the axle journal components60,70.

A curved groove65can be seen in the first axle journal component60inFIGS. 5 to 7. The curved groove65has two substantially parallel curved sliding faces66,67which are, however, variously wide. The groove65essentially extends totally inside the region of the axle journal63, more precisely inside a circular cylindrical region of space, the radial surface of which corresponds in portions to the radial surfaces64,74of the axle journals63,73of the axle journal components60,70(cf.FIGS. 5 and 6). The second axle journal component70is realized in a mirror symmetrical manner to the first axle journal component60and has, in particular, a curved groove, which corresponds mirror symmetrically to the groove65on the first axle journal component60and is not able to be seen inFIGS. 5 to 7.

A curved web35with a first sliding face36and a second sliding face37can be seen on the second bar34on the distal end of the transferring device30. The first bar33has a web which is curved in a mirror-symmetrical manner to the curved web35on the second bar34. The widths and the curvatures of the curved grooves65on the axle journal components60,70and the widths and the curvatures of the webs35on the bars33,34of the transferring device30correspond to one another such that the webs35on the bars33,34are guided low in play and friction in the grooves65on the axle journal components60,70when the distal end of the transferring device30is inserted into the basic body50and the axle journal components60,70.

After inserting the axle journals63,73into the recess53in the basic body50and coupling the bars33,34with the axle journal components60,70by inserting the curved web35into the curved groove65, the bars62,72of the axle journal components60,70are connected together by a basic body (not shown inFIGS. 3 to 7) of the pivotable mouth part42(cf.FIGS. 1 and 2). The basic body of the pivotable mouth part42has, in particular, bores or grooves into which the bars62,72of the axle journal components60,70are inserted. The mentioned basic body of the pivotable mouth part42holds the axle journal components60,70in their relative position shown inFIGS. 3, 4, 6 and 7and consequently holds the axle journals63,73in the recess53in the basic body50.

FIGS. 8 and 9show schematic axonometric representations of the basic body50, the axle journal components60,70and the transferring device30. The representations inFIGS. 8 and 9, with regard to the positions of the transferring device30and of the axle journal components60,70, correspond to the representations inFIG. 3 or 4. Contrary to the representations inFIGS. 3 and 4, the sleeve45on the proximal end of the basic body50is not shown inFIGS. 8 and 9. As a result, the first bar33is visible to a greater extent. It can be seen inFIGS. 5 to 9that the basic body50, parallel to the operating channel58and on the outside abutting against the two longitudinal webs56,57, has two grooves in which the bars33,34are guided (cf.FIG. 7).

FIG. 8also shows a scalpel80which is arranged in the operating channel58of the basic body50so as to be slidable in the direction81parallel to the longitudinal axis28(cf.FIGS. 1 to 4). Proximally of the basic body50, the scalpel80lies in a groove31in the transferring device30which continues the operating channel58in the proximal direction. In particular, the scalpel80extends as far as up to the handling device15(cf.FIG. 1) in order to make a movement of the scalpel80possible from the handling device15. Corresponding devices on the handling device15are not shown inFIG. 1.

FIGS. 10 and 11show schematic representations of cross sections through the basic body50, the axle journal components60,70and the scalpel80.FIG. 11also shows cross sections of the bars33,34. The contours of the mouth parts41,42are indicated by the dotted lines. BothFIGS. 10 and 11show the pivotable mouth part42with the axle journal components60,70in the closed position which is also shown inFIGS. 2, 4, 7 and 9.

The cutting planes ofFIGS. 10 and 11are at right angles with respect to the longitudinal axis28(cf.FIGS. 1 to 4) and to the drawing planes ofFIGS. 1 and 2. The cutting plane ofFIG. 10is distally of the connecting pin59between the longitudinal webs56,57of the basic body50(cf.FIGS. 4 and 9). The cutting plane ofFIG. 11includes the pivot axis48of the pivotable mouth part42(cf.FIGS. 2 and 5 to 7).

The design of the basic body50with the base plate51arranged horizontally inFIGS. 10 and 11and the longitudinal webs56,57arranged vertically inFIGS. 10 and 11can be seen in each case inFIGS. 10 and 11. In addition, the operating channel58between the longitudinal webs56,57and the scalpel80in the operating channel58can also be seen. The cutting plane ofFIG. 10intersects the two bars62,72of the axle journal components60,70. The cutting plane ofFIG. 11intersects the axle journals63,73of the axle journal components60,70and the bars33,34of the transferring device30(cf.FIGS. 3, 4, 8 and 9). It can be seen in the cross section shown inFIG. 11how the webs35on the bars33,34engage in the corresponding grooves on the axle journal components60,70.

In addition, it can be seen how the axle journals63,73engage in the longitudinal webs56,57of the basic body50. In this case,FIG. 11shows two different variants of the axle journals63,73. The axle journal63of the first axle journal component60engages in a corresponding recess, which is realized as a through-bore, in the first longitudinal web56and reaches as far as up to the operating channel58. The axle journal73on the second axle journal component70engages in a recess, which is realized as a blind hole, on the second longitudinal web57of the basic body50. The axle journal73of the second axle journal component70is consequently separated from the operating channel58by a thin region of the second longitudinal web57. Deviating from the representation inFIG. 11, a tool has, in particular, two mirror-symmetrical axle journal components60,70and two mirror-symmetrical longitudinal webs56,57. The engagement of the two axle journals in the longitudinal webs56,57corresponds consequently, in particular, either to the first axle journal63shown inFIG. 11in the first longitudinal web56or to the second axle journal73shown inFIG. 11in the second longitudinal web57.

In addition, the basic body46, already mentioned in the description ofFIGS. 5 to 7, can be seen inFIGS. 10 and 11, said basic body holding the axle journal components60,70in their relative position shown inFIGS. 3, 4, 6 and 7and consequently holding the axle journals63,73in the recess53in the basic body50. To this end, the basic body46has grooves, which can be seen, in particular, inFIG. 10and in which the bars62,72of the axle journal components60,70are held in a positive locking manner.

FIGS. 12 and 13show schematic representations of a section through the first bar33and the first axle journal component60(cf.FIGS. 3 to 11). The cutting planes ofFIGS. 12 and 13are parallel to the longitudinal axis28(cf.FIGS. 1 to 4), to the drawing planes ofFIGS. 1 and 2and at right angles to the pivot axis48of the pivotable mouth part42(cf.FIGS. 2 and 5 to 7) as well as to the cutting planes ofFIGS. 10 and 11. The cutting planes ofFIGS. 12 and 13are arranged such that they intersect the groove65on the first axle journal component60and the web35on the first bar33. The contours of the fixed mouth part41and of the pivotable mouth part42are indicated by the dotted lines.

FIG. 12shows the bar33in the distal position and the pivotable mouth part42with the axle journal component60in the open position, these are also shown inFIGS. 3 and 8.FIG. 13shows the bar33in the proximal position and the pivotable mouth part42with the axle journal component60in the closed position, these are also shown inFIGS. 4 to 7 and 9 to 11. In addition,FIGS. 12 and 13show the center of curvature38of the curved web35on the bar33(and consequently of the sliding faces36,37on the curved web35) and of the curved groove65(cf.FIGS. 5 to 7) on the axle journal component60(and consequently of the sliding faces66,67of the curved groove). The center of curvature38lies outside the tool40or outside the contours thereof, which are indicated inFIGS. 12 and 13by the dotted lines.

List of references10Medical instrument11Proximal end of the medical instrument 1012Distal end of the medical instrument 1015Handling device20Shaft of the medical instrument 1021Proximal end of the shaft 2022Distal end of the shaft 2028Longitudinal axis of the shaft 2030Transferring device31Longitudinal groove in the transferring device 3032Distal end of the transferring device 3033First bar on the distal end of the transferring device 3034Second bar on the distal end of the transferring device 3035Curved web on a bar 33, 3436First sliding face on the web 2537Second sliding face on the web 3538Center of curvature of the web 3540Tool41Fixed mouth part of the tool 4042Pivotable mouth part of the tool 4043Bearing45Sleeve46Basic body of the pivotable mouth part 4248Pivot axis of the pivotably mounted mouth part 4050Basic body of the tool 4051Base plate of the basic body 5053Recess on the basic body 5056First longitudinal web on the basic body 5057Second longitudinal web on the basic body 5058Operating channel between the longitudinal webs 56, 57of the basic body 5059Connecting pin60First axle journal component of the pivotably mountedmouth part 4261Insertion movement62Bar of the first axle journal component 6063Axle journal on the first axle journal component 6064Radial surface of the axle journal 6365Groove on the first axle journal component 6066First sliding face on the groove 6567Second sliding face on the groove 6570Second axle journal component of the pivotably mountedmouth part 4071Insertion movement72Bar of the second axle journal component 7073Axle journal on the second axle journal component 7074Radial surface of the axial pin 7380Scalpel81Direction of movement of the scalpel 80