DE102016118158B3 - Bendable shaft tube of a medical instrument, medical instrument and method for producing a flexible shaft tube - Google Patents

Abstract

The invention relates to a shaft tube (10) of a medical instrument for endoscopic interventions with a bendable section (12) which is controlled by actuation of pull wires (14), wherein the bendable section (12) consists of a plurality of torsionally articulated tubular piece skeleton elements ( 16), wherein the skeleton elements (16) have in their first axial end region two rod ends (20) arranged on opposite sides of their tube wall (18) and in their second axial end region opposite the first end region two on opposite sides of the tube wall (18). arranged jointed sockets (22), wherein the rod ends (20) of a first skeletal element (16) in the joint sockets (22) of an adjacent skeleton element (16) store, and wherein at least some of the skeleton elements (16) in each case two on the tube wall (18) arranged holding tongues (24), each with a free Haltee (26) in the region of the joint sockets (22) protrude and in the joint sockets (22) mounted rod ends (20) with respect to the longitudinal axis of the skeleton element (16) contact supporting in radially opposite directions.

Description

The invention relates to a shaft tube of a medical instrument according to the preamble of claim 1, a medical instrument having a shaft tube according to the invention according to claim 8 and a method for producing a shaft tube according to the invention.

For a controlled bending of a shaft, various mechanisms are known from the prior art. Skeletal structures made of hingedly interconnected members are particularly frequently used, which have guides on each opposite side of their inner wall for sliding bearing of one or more bendable puller wires. The puller wires are attached to a control head in the distal region of the shaft so that they can be moved under tensile load. Upon tensile loading of the wires of a first side, the links are each pivoted about their axes of rotation, and the shaft is thus forcibly moved into a bending position. When the wires on the opposite side are subjected to tensile stress, the bending is reversed. Such constructions are for example in JP 2009112538 A and EP 1681013 A1 shown.

The execution of the hinges with pin axes has proved to be problematic in the known bending shops. The hinges are loaded in some applications with very high bending forces, which significantly increases the wear of these joints and excludes the use of instruments in various endoscopic applications due to the risk of breakage of the pivot pins. This is particularly noticeable in instruments with very small sizes and very small shank diameters.

In addition, the production of such Achsstift pivot joints is complicated and time-consuming, since the pin axes usually must be pressed by hand and with high precision in overlapping areas of the skeletal elements to produce identical friction forces in the joint region of the articulated skeleton elements. Uneven frictional forces would lead to a hakeligen or non-uniform bending movement when bending the instruments. In addition, the trained for the displaceable guided in the shaft tube pull wires guide elements must be secured in the passage of the skeleton elements, which represents a high technical challenge for the assembly or production of such bendable shaft tubes because of the small component dimensions and poor accessibility of the mounting areas.

Known in addition to the classic shaft tubes with independently bendable areas and shaft tubes with two correlated bendable areas, which are spaced apart by a bending-resistant portion, wherein a bend of the first bendable area leads to a rectified or opposite bending of the second bendable area. Such a construction is for example in DE 102009037030 A1 shown. These shafts are traversed to the bending control distributed over the circumference arranged control rods. If one of the two bendable sections is bent, one or more of the control rods in this section will be shortened and others extended in this section. The change in length is transmitted to the second bendable area, which is thereby forcibly moved into a bending position.

Overall, it can be seen in the known constructions that they are characterized by a high component complexity and are expensive to assemble. This makes these designs expensive and maintenance-intensive. As miniaturization progresses, the risk of material defects increases with high holding or actuating force loading on the control wires or rods.

US 9211134 B2 describes a steerer tube having a bendable section consisting of a plurality of pivotally mounted tubular skeletal elements.

Object of the present invention is to provide an improved shaft tube of the type mentioned, which can be produced in a few steps and is characterized by low component complexity.

The object is achieved by a shaft tube having the features of claim 1. According to the invention is also a medical instrument having the features of claim 8 and a method having the features of claim 9. Advantageous embodiments are specified in the dependent claims.

According to the invention, a shaft tube of a medical instrument for endoscopic procedures with a bendable portion which is controlled bendable by actuation of pull wires, wherein the bendable portion of a plurality of rotatably mounted to each other pivotally mounted tubular skeleton elements is formed, wherein the skeletal elements in its first axial end portion two at opposite Sides of their tube wall having arranged rod ends and having in its first end region opposite the second axial end region arranged on opposite sides of the tube wall, two sockets, the joint heads of a first skeletal element in the joint sockets of an adjacent skeletal element store, and wherein at least some of the skeletal elements each two at the pipe wall having arranged retaining tongues, each projecting with a free holding end in the region of the joint sockets and contact supporting the joint heads mounted in the sockets with respect to the longitudinal axis of the skeletal element in radially opposite directions.

The shaft tube according to the invention can be used for example on a colonoscope. Such flexible endoscopes, which are predominantly used for visual examination of the large intestine, are also used for biopsy and for performing bowel surgery. Endoscopes of this type typically lead in the shaft passage light guide for illumination, image transfer, cables for controlling the endoscope, channels for rinsing water and suction and a working channel for work tools such as pliers, injection needle, slings and the like. Controlled bendable regions of such endoscopes are often arranged in the distal end region of the shaft. For gentle and safe control of the endoscope is a well controllable and smooth over longer bending distances bending control of the shaft tube is very important.

Without further ado it is also conceivable to use the steerer tube according to the invention in endoscopes used in other medical fields of application. For example, the shaft according to the invention can also be used on gastroscopes or on instruments for laparoscopic surgery.

The bendable shaft region of such flexible endoscopes is usually controlled by the train of individual guided in the shaft Bowden cables. Depending on the number of possible deflection directions can be provided to lead longitudinally displaceable two or four such puller wires in the passage of the shaft. The Bowden cables are typically guided by eyelets fastened inside the shaft. At an arranged in the distal end portion of the bendable shaft portion eyelet or on a distal control element of the Bowden cable is fastened tensile strength.

In one embodiment, the further development of the shaft tube according to the invention is provided to fasten the eyelets for simplified mounting on the retaining tongues, wherein the retaining tongues protrude into the interior of the skeleton members through openings of the tube wall provided for this purpose. Usually, the eyelets are attached to the inner wall of the movable chain links by soldering. This manufacturing step is time consuming and expensive. The insertion of retaining tongues with eyelets fastened thereto, on the other hand, is significantly simpler and significantly shortens the manufacturing process of a shaft tube according to the invention.

To simplify the production of flexible shaft tubes, a method was first developed, according to which the pull wire guide elements are produced as stamped and bent parts and several of these parts are offset by an offset angle into a tube. From this assembly, the skeleton members were then cut by laser cutting. However, this manufacturing process has proven to be quite expensive, since the laser cutting work had to be generated with a five-axis laser cutting machine to cut out the skeleton members separated in the cutting process so that a positive connection in the joints is made. The positive connection was necessary to prevent the chain from falling apart.

In this manufacturing process, the pre-assembly has proven to be very time consuming and especially for very small shank diameters as technically problematic. Since the pull wire guide elements must be subsequently welded into the pipe in this manufacturing process, a fixation of the guide elements in the tube and a pressing of the elements to the inner wall of the tube is necessary in a first step. Errors in this pre-assembly can hardly be detected and possibly lead to an unusable shaft tube. In addition, the cutting of 3D contours on a five-axis laser cutting machine is very time-consuming and therefore very expensive. The precision required in the miniaturization of the instruments is also not economically feasible in such cutting processes.

In the shaft tube according to the invention, however, the individual skeleton members are held by the use of separate retaining tongues against each other form fit. In the manufacturing process can be dispensed with the use of a five-axis laser cutting machine. The otherwise necessary, to the longitudinal axis of the skeletal elements conical section between the condyle and the socket is no longer necessary in the shaft tube according to the invention.

In the shaft tube according to the invention, it is provided that the bending control is controlled by means of tensile loading of the tension wires passing through the shaft tube. The shank according to the invention can be bendable in two planes, for example. Four puller wires are preferably provided for this purpose, with a first pair of puller wires controlling the bending in two directions of a first deflection plane and a second pair of puller wires controlling the bending in two directions of a second deflection plane.

An important aspect of the shaft tube according to the invention is the non-rotatable pivotal mounting of the skeletal members together. In the state In the art, the skeletal members of a bendable shaft portion are usually hinged together with pivot pins. Typically, the skeletal links are riveted together. If these riveting operations are not carried out with constant forces, different rotational friction forces arise between adjacent skeleton members, which can lead to non-uniform and hooking bending movements.

In the case of the shaft tube according to the invention, on the other hand, provision is made for the skeleton elements to be connected to one another in the manner of a hinge joint. For this purpose, the skeleton elements, which are designed in particular with a circular inner cross-section, have in particular plate-shaped rod ends at a first axial end region and socket cups corresponding to the rod ends at their axial second end region. A distal end of a skeletal element can thus be connected to the proximal end of a skeletal element pivotally. Preferably, the rod ends are arranged at the distal end of a skeletal element and the socket joints at the proximal end of the skeletal element.

The rod ends are preferably in the form of an integrally formed extension of the tube wall of a skeletal element in the axial direction, in particular in the distal direction. The joint sockets are preferably incorporated recess-like as breakthroughs in the tube wall of a skeletal element. More complicated but also conceivable is the attachment of separate rod ends or joint pans on the skeletal elements. The rod ends and joint sockets of a skeletal element are each arranged offset by a circumferential angle of 180 ° to each other on the tube wall. In other words, the axes of rotation defined by the joint heads or joint sockets of a skeletal element intersect the centrally extending longitudinal axis of the skeletal element. Preferably, the rod ends and / or the socket joints are formed integrally with the tube wall, that is integrally formed or cut out in a materially cohesive manner.

The rod ends, which are approximately dish-shaped or part-circular in one embodiment, are preferably mounted with a neck area in the axial direction at a distance from the tube wall of a skeleton member. The rod ends and joint pans are located in front of each other in axial directions opposite to the ends of a skeletal element. The sockets are preferably aligned transversely to the longitudinal axis of the skeletal element circular openings of the tube wall with an opening on the frontal contour of the skeletal element. The front opening passes through the neck area of a joint head for the articulated connection of the two elements. The sockets surround the rod ends while pliers like with a wrap angle of more than 180 °, so that with the interlocking joint partners a tensile bond between the skeletal elements is made.

The joint pans and joint heads arranged opposite one another on a skeletal element in the axial direction each define an axis of rotation which intersects the longitudinal axis of the tubular skeleton element. The two axes of rotation of a skeletal element can be offset from each other as seen in the axial direction of the skeleton element with an offset angle. By offsetting rod ends to socket joints of a skeletal element, the shaft tube can be controlled controlled in two different Auslenkebenen.

An advantage of the formation of sockets and condyles in the tube wall of the skeletal elements is that the rod ends engage flush in the socket joints in the position of use of the skeletal elements. In the extended position of the skeletal elements thus creates a continuous, low-gap common outer circumferential surface of the flexible shaft tube section, which simplifies a further sheathing of the shaft tube.

The rod ends are held by retaining tongues in the joint sockets according to the invention. In order to prevent the rod ends from falling out of the socket joints, the retaining tongues are arranged in such a way that they respectively support the rod ends radially inward or radially outward. A transverse displacement of two adjacent skeletal elements along a rotation axis is thus prevented. Particularly preferred is a variant, according to which the holding tongues contact the rod ends pointing radially outward with their holding ends. The holding ends of the retaining tongues can thus be arranged radially inward in the passage of the skeleton elements, which benefits the formation of a stepless outer lateral surface.

The puller wires are connected in the distal region of the bendable shank section in a tension-proof manner to a skeleton element or a control element. The pull wires pull at tensile load on the control and force the control while the lateral deflection, resulting in a bending of the shaft tube in a first deflection. The forced bending of the shank is achieved in that the puller wires are guided eccentrically to the longitudinal axis of the shaft tube and thus transmit a force with radially outwardly oriented directional component to the control.

To simplify the mounting of the shaft tube is thought that the retaining tongues are fastened with a mounting portion on the outer periphery of the skeleton element and with the Halteende protrude through a breakthrough of the tube wall of the skeletal element in the tubular passage of the skeletal element.

The retaining tongues are guided in this embodiment by openings on the pipe wall of a skeleton element in the interior of the tube. The holding ends of the retaining tongues protrude into the passage of the skeletal element and can secure the rod ends directed radially outward against lateral displacement and against falling out of the joint sockets. The attachment region of the retaining tongues bears against the outer tube wall of the skeleton element and is there joined to the tube wall, in particular adhesively bonded, welded, and / or soldered.

For a flat as possible outer surface of the shaft tube can be provided that the mounting portions of the retaining tongues are arranged in embossed on the outer pipe wall mounting pockets. The radially outwardly facing surface of the attachment regions can be shaped correspondingly to the outer contour of the skeletal element in order to produce as flush as possible or step-free transition between the outer circumferential surface of the skeleton element and the attachment region of the retaining tongue. In particular, the surface of the attachment region may be curved like a tubular segment.

In order to improve the rotational hinge properties, it is envisaged that the surface of the holding end of the retaining tongue which contacts the condyle is spherically convexly shaped. Due to the spherically convex shape of the surface of the retaining end of the retaining tongue, the surface of the retaining end follows the inner contour of the joint heads, which is determined by the tubular shape of the skeleton element. This uniform and smooth turning properties are generated in the contact area between retaining tongue and condyle.

The spherically convex shape of the holding end corresponds approximately to the shape of a spherical surface area. The diameter of the spherical surface preferably corresponds to the tube inner diameter of the skeleton element held by the retaining tongue.

To implement the bending control of the shaft can be provided that the bending of the bendable section is controlled by tensile load of one or more within the passage of the skeletal elements longitudinally displaceable pull wires, wherein the longitudinally displaceable guidance of the puller wires per skeletal element two guide eyelets are arranged stationary to the skeletal element within its passage ,

To further simplify the assembly of the shaft and to reduce the component complexity is thought in a preferred embodiment, that the puller wires are guided in longitudinally displaceable in arranged on the retaining tongues guide eyelets.

With the arrangement of the guide eyelets on the retaining tongues, the assembly of the shaft according to the invention is significantly simplified. In this embodiment, it is provided that the guide eyelets are arranged in the region of the holding end of a retaining tongue. The guide eyelets can thus be inserted together with the holding end in the interior of the tube. Subsequent welding of the guide eyelets into the passage of the skeleton elements is no longer necessary.

It has been found that the holding tongues according to the invention can be produced particularly well by powder injection molding, in particular by metal powder injection molding. Thus, the retaining tongues according to the invention can be provided low in large quantities even with complex geometries and even with integrated guide sleeve.

For a particularly smooth bending control can be provided that the guide eyelets is arranged with the axis of rotation defined by the joint socket with the condyle at the holding end. In this embodiment, it is provided in particular that the longitudinal axis of the guide eye intersects the axis of rotation of the condyle head contacting the holding end.

To provide a steplessly bendable shaft tube, it is envisaged that the rod ends of a skeletal element are offset from the socket plates on the tube wall of the skeleton element with an angular offset so that the bendable section can be controlled in different deflection directions.

In this preferred embodiment, the axes of rotation of a skeletal element defined by the respective opposite rod ends and joint pans are at different angular positions relative to each other, wherein the axes of rotation extend at a right angle to the longitudinal axis of a skeletal element. Seen in the axial direction of a skeletal element, there is thus an angular offset between the proximal and the distal axis of rotation of a skeletal element.

Preferably, the two axes of rotation of a skeleton element are aligned offset by 90 ° to each other. Alternatively, other offset angles are conceivable, in particular 30 ° or 45 °, depending on the intended use of the instrument.

In one embodiment of the shaft tube with controllable flexibility in only a single deflection plane, the eyelets are attached to the inner wall of the tube relative to the axis of rotation defined by the pivot axes of a skeleton element offset by a circumferential angle. A tensile force on a pull wire thus forces the skeletal elements to diffract about the axes of rotation.

The attachment of the guide eyelets to the retaining tongues is provided in particular in the embodiment of the shaft tube according to the invention with two Auslenkebenen. The guide eyelets can be arranged in each case directly aligned with the axis of rotation of a joint below the holding end of a retaining tongue. The pull wires which intersect the first axis of rotation of a skeletal element in this embodiment in their longitudinal direction thereby control the bending around the second axis of rotation of the same skeleton element, which axis runs at the first angle offset.

Also according to the invention is a medical instrument with a shaft tube according to the invention. Advantages and details of the instrument according to the invention will become apparent in particular from the explanations on the embodiments of the shaft tube according to the invention.

According to the invention is further a method for producing a shaft tube, in particular a bendable portion, according to one of the variants described in the joint for articulation of skeletal elements of a bendable portion of the shaft tube rod ends by means attached to the tube wall of the skeletal elements holding tongues against falling out of the joint heads corresponding socket joints secured, characterized in that the method comprises the steps of: providing an elongate tube; Separating the tube into tubular skeletal elements and incorporation of joint sockets and rod ends in the tube wall of the skeleton elements and incorporation of formed for the protruding arrangement of a retaining tongue breakthroughs in the tube wall of the skeleton elements; Insertion of retaining tabs in the openings of the skeletal elements and attachment of the retaining tabs on the skeletal elements.

The holding tongues are preferably produced in the powder injection molding, in particular in the metal powder injection molding process (MIM - Metal Injection Molding).

In one embodiment, the method comprises the step of incorporating fastening pockets provided for fastening the retaining tongues into the tube wall of the elongate tube.

The attachment pockets on the outer periphery of the skeleton elements are preferably formed by a so-called "hydroforming" in the provided tubular body. Hydroforming is also known as hydroforming (IHU). In this case, a fluid, such as a water-oil emulsion is introduced into the provided tube and pressurized. The tube expands radially and the tube wall nestles against an externally applied mold.

Fastening areas of the holding tongues come to rest in the attachment pockets and can be connected to the tube wall of the skeleton elements in a positive, force and / or materially bonded manner.

In one embodiment, the method comprises the step: incorporation of holding troughs provided for the tensile fastening of a pull wire end into the tube wall of the elongate tube.

The holding wells can be incorporated simultaneously with the mounting pockets in the tube wall of the elongated tube. Like the attachment pockets, the holding troughs can be molded into the tube by hydroforming. The holding wells extend radially inwardly into the tube and are each pierced to pass the puller wires.

It is envisaged that the portion of the elongate tube having the holding wells is separated from the remainder of the tube and forms a control of the bendable portion of the stem tube. This is especially provided that the puller wires are held tensile strength in the holding troughs. For a high-tensile connection between the control element and the puller wire, one end of the puller wire, for example using a laser, can be remelted to form a ball or other thickening, which lies in the recess after threading the puller wire through the wellbore. The querschnittserweiterten ends of the puller wires thus do not protrude beyond the outer circumference of the shaft tube. In addition, it can be provided that the querschnittserweiterte end of the puller wire is fixed in the trough with adhesive or welded in the trough with the outer wall of the control or soldered.

For articulated connection between the control element and an adjacent skeletal element, joint heads or joint pans are arranged on the control element proximal to the holding recesses and form a pivot joint in engagement with corresponding joint partners of the adjacent skeletal element. The control can so far similar to the skeleton elements described with two be arranged on its proximal end surface joint cups.

More preferably, the method comprises the step of drawing in a pull wire in guide eyelets attached to the holding tongues.

In a further preferred embodiment, the method comprises the step of drawing in a pull wire in guide eyelets fastened to the holding tongues.

Embodiments and details of the invention are described in more detail below with reference to highly schematic representations. Show it:

1 a representation of a surgical instrument with a flexible shaft tube,

2 a representation of several skeleton members of a shaft tube according to the invention,

3 a representation of an invention measured holding tongue in a side view,

4 a plan view of the retaining tongue 3 .

5 a tubular body in a side view,

6 the tubular body 5 with embossed attachment pockets and holding troughs,

7 the tubular body 6 with indicated cutting lines for the formation of individual skeletal elements with openings for the retaining tongues and cutting lines for the formation of rod ends and joint sockets, and

8th two exemplary bending positions of the shaft tube according to the invention.

1 shows a surgical instrument with a shaft tube according to the invention 10 , In this embodiment, the shaft tube comprises 10 a proximal bending resistant section 40 and a distal controlled bendable section 12 ,

At the distal end portion of the shaft tube 10 is a tool 42 hitched. The tool 42 can - as shown - be a jaw part with two mutually relatively movable mouth sectors. According to this variant, the tool 42 by the longitudinal displacement of a tension and compression-resistant actuating rod 44 in the tubular shaft 10 actuated. For this, the operating rod 44 in the proximal end region of the shaft tube 10 on a handle part of a handle 46 be coupled. An operation of the handle 46 acts on the actuating rod 44 with a tensile or compressive force against the shaft 10 , This displacement force can be used, for example, to open or close the tool designed as a jaw part 42 at the distal end of the shaft 10 serve.

The shaft tube 10 can rotate against the handle 46 be educated. For this purpose, a trained as a rotary knob control device, for example 48 on the shaft tube 10 be arranged. For rotary actuation of the shaft tube 10 can the controller 48 opposite the handle 46 be rotatably mounted.

The control device 48 may alternatively or additionally be arranged and designed, the bendable portion 12 of the shaft tube 10 to steer in a bending position. For the control device 48 For example, hand-operated levers or knobs (not shown), with which one in the proximal longitudinal direction of the shaft 10 directed pulling force on one or more puller wires 14 can be exercised.

2 shows purely schematically three adjacent skeletal elements 16 a shaft tube according to the invention 10 , The skeletal elements 16 are shown separated from each other for the sake of clarity. In the working position are the skeletal limbs 16 jointed together.

Clearly visible are the skeletal elements 16 the rod ends 20 and joint pans 22 that are in the pipe wall 18 the skeletal elements 16 are formed. The rod ends 20 are approximately plate-shaped with a neck portion of the main body of the condyle 20 from the frontal contour of the skeletal elements 16 spaced. The skeletal elements 16 are in 2 shown from the side, they have a tubular cross section, in particular a round tube-shaped cross-section with one of the pipe wall 18 enclosed passage. The passage is preferably also round-tubular or circular.

In 2 are furthermore retaining tongues according to the invention 24 in on the skeletal links 16 arranged position indicated. The retaining tongues 24 protrude with their holding ends 26 in the area of the joint pans 22 and lie with their attachment areas 28 in on the outside wall of the skeleton elements 16 incorporated mounting pockets 36 , The retaining tongues 24 are drawn dashed lines for clarity. On the outer wall, the retaining tongues 24 be secured with good accessibility, for example, by welding, gluing or soldering, which greatly facilitates the assembly of a shaft tube according to the invention.

In the passage of skeletal elements 16 are - for the sake of clarity drawn with dot-dash lines drawn - pull wires 14 guided longitudinally displaceable. The puller wires 14 are present in each case by guide eyelets 32 guided radially inward at the holding ends 26 the retaining tongues 24 are arranged.

In the embodiment shown, the skeleton elements 16 staggered pairs of rod ends 20 and joint pans 22 on. The through the distal on opposite sides of the tube wall 18 arranged rod ends 20 defined first axis of rotation of a skeleton element 16 in the present case is 90 ° to the proximal arranged by the joint sockets 22 defined second axis of rotation offset. Thus, the in 2 shown bendable section 12 be bent in two, 90 ° to each other Auslenkebenen. By a superposition of the deflection movements, the bendable shaft can thus be moved in an approximately funnel-shaped deflection space.

The offset angle between the first and the second axis of rotation of a skeleton element 16 is selected in the present example with 90 °. The distally arranged rod ends are accordingly 20 a first skeletal element 16 in the plane of the drawing, front and back (hidden) and the proximal joint sockets 22 above and below. The rod ends 20 and the sockets 22 an adjacent skeletal element 16 are shown offset by 90 °. In this position, the skeletal elements 16 be merged so that the rod ends 20 in corresponding joint sockets 22 an adjacent skeletal element 16 can intervene.

The 3 and 4 show purely schematically a retaining tongue 24 with a fastening end 28 and a stop-end 26 and one in the area of the holding end 26 arranged guide sleeve 32 , In 3 can be the preferred embodiment of the retaining tongue 24 recognize in Z-shape. Here is the attachment end 28 opposite the holding end 26 stepped so that the attachment end 28 on the outer circumference of the pipe wall 18 a skeleton element can be fastened, wherein at the same time the radially inwardly stepped holding end 26 into the passage of a skeletal element 16 can protrude.

In the side view of 3 is a spherically convex curvature on the radially outwardly facing surface of the retaining end 26 to recognize. Below the curvature, on the radially inner side of the holding end 26 is the guide eye 32 arranged. As in 2 indicated, lies the guide eye 32 in the assembled state of the skeletal elements 16 aligned with the axis of rotation below one with the retaining tongue 24 held condyle 20 ,

4 shows the retaining tongue 24 out 3 in plan view according to the line of sight 4-4. It can be seen that the attachment area 28 in the direction of the stopping end 26 concludes with an arcuate, in particular circular contour, which - as compared to 3 to recognize - a step to the stop 26 formed. This rounded contour can optionally be provided to be in a corresponding breakthrough 30 on the pipe wall 18 of the skeletal element to abut. The rounded contour at the transition of the mounting area 28 to the end of the hold 26 can as a guide in the assembly of the shaft tube according to the invention 10 serve as for the positioning of the retaining tongue 24 in their implementation by the intended breakthrough 30 in the pipe wall 18 a skeletal element 16 facilitated.

The 5 - 7 show purely schematically possible process steps in the manufacture of a shaft tube according to the invention 10 , First, according to 5 an elongated, preferably formed with a circular outer and inner cross-section tube 34 provided. The pipe 34 will - as in 6 indicated - by forming with attachment pockets 36 and holding troughs 38 fitted. The attachment pockets 36 and the holding troughs 38 can do this with a hydroforming process (hydroforming) in the tube wall of the elongated tube 34 be formed. Such forming processes are well known in the art and may be used to simplify the manufacturing process. The pipe 34 and thus the parts made therefrom are preferably made of metal, in particular of a stainless steel, but may also be made of a plastic. Hydroforming process is suitable for a design of the pipe 34 made of metal.

In 7 dashed lines are shown possible cutting lines, which can be traced, for example, with a cutting laser or other cutting tool. By cutting out the skeletal elements 16 out of the pipe 34 can in the same process step the contours for the formation of the rod ends 20 and the sockets 22 into the pipe wall of the long pipe 34 be cut.

Before or after cutting the joint structures with rod ends 20 and joint pans 22 can the breakthroughs 30 for passing the retaining tongues 24 into the pipe wall of the pipe 34 preferably also be cut by laser cutting.

After cutting out the skeletal elements 16 out of the pipe 34 are the rod ends 20 and the sockets 22 engaged with each other so that the skeletal elements 16 already articulated with each other. Without those in the breakthroughs 30 inserted holding tongues 24 exists between the skeletal elements 16 along the through the swivel joints 20 . 22 defined axes of rotation, however, no positive connection, so that a lateral displacement along the axes of rotation for separating the skeleton elements 16 would lead. Only by inserting the retaining tongues 24 become the rod ends with respect to the longitudinal axes of the skeletal elements 16 pointing radially outwards with the holding hands 26 the retaining tongues 24 supported, so that a lateral displacement of the skeletal elements 16 prevents each other.

With 50 is the distal region of a bendable section 12 a shaft tube according to the invention 10 shown. This distal area 50 contains the tension-proof fastening of the puller wires 14 prepared holding troughs 38 , The area 50 forms the distal control of the bendable section 12 , by transmission of tensile forces by means of pull wires 14 the skeletal elements 16 for rotation around with the rod ends 20 and the sockets 22 forced swivel joints and thus brings the shaft into the bending position.

8th shows purely schematically different bending positions of the shaft tube according to the invention in a deflection plane. In the present embodiment, the bendable portion of the shaft tube is controlled in two different Auslenkebenen bendable on the one hand in the plane of the drawing and on the other hand perpendicular to the plane of the drawing. In 8th the deflection in drawing plane is shown in opposite directions.

LIST OF REFERENCE NUMBERS

10

 steerer

12

 Bendable section

14

 pull wires

16

 skeletal element

18

 pipe wall

20

 joint head

22

 socket

24

 holding tongue

26

 holding end

28

 fastening area

30

 breakthrough

32

 guide eye

34

 Elongated pipe

36

 fixing case

38

 holding trough

40

 Proximal bending resistant section

42

 Tool

44

 actuating rod

46

 handle

48

 control device

50

 Distal area of the bendable section

Claims (12)

Shaft tube ( 10 ) of a medical instrument for endoscopic procedures with a bendable section ( 12 ) operated by pulling wires ( 14 ) is bendable controlled, wherein the bendable section ( 12 ) of a plurality of non-rotatably mounted to each other pivotally tubular piece-shaped skeleton elements ( 16 ), and wherein the skeletal elements ( 16 ) in its first axial end region two on opposite sides of its tube wall ( 18 ) arranged rod ends ( 20 ) and in its second axial end region opposite the first end region, two on opposite sides of the tube wall (FIG. 18 ) arranged joint pans ( 22 ), and wherein the rod ends ( 20 ) of a first skeletal element ( 16 ) in the joint pans ( 22 ) of an adjacent skeletal element ( 16 ), characterized in that at least some of the skeletal elements ( 16 ) two each on the pipe wall ( 18 ) arranged holding tongues ( 24 ), each with a free holding end ( 26 ) in the area of the joint pans ( 22 ) and in the sockets ( 22 ) rod ends ( 20 ) with respect to the longitudinal axis of the skeletal element ( 16 ) contact supporting in radially opposite directions. Shaft tube ( 10 ) according to claim 1, characterized in that the retaining tongues ( 24 ) with a fastening area ( 28 ) on the outer periphery of the skeletal element ( 16 ) are attached and with the holding end ( 26 ) through a breakthrough ( 30 ) of the pipe wall of the skeleton element ( 16 ) in the tubular passage of the skeletal element ( 16 ) protrude. Shaft tube ( 10 ) according to one of claims 1 or 2, characterized in that the condyle ( 20 ) contacting surface of the retaining end ( 26 ) of the retaining tongue ( 24 ) is spherically convex. Shaft tube ( 10 ) according to one of the preceding claims, characterized in that the bend of the bendable section ( 12 ) by tensile loading of one or more within the passage of the skeletal elements ( 16 ) longitudinally displaceable pull wires ( 14 ) is controllable, wherein the longitudinally displaceable guidance of the puller wires ( 14 ) per skeleton element ( 16 ) two guide eyelets ( 32 ) are arranged stationary to the skeletal element within its passage. Shaft tube ( 10 ) according to one of the preceding claims, characterized in that the Pull wires ( 14 ) in at the retaining tongues ( 24 ) arranged guide eyelets ( 32 ) are guided longitudinally displaceable. Shaft tube ( 10 ) according to claim 5, characterized in that the guide eyelets ( 32 ) with the through the joint socket ( 22 ) with the condyle ( 20 ) defined axis of rotation at the holding end ( 26 ) is arranged. Shaft tube ( 10 ) according to one of the preceding claims, characterized in that the rod ends ( 20 ) of a skeletal element ( 16 ) offset with an angular offset to the joint sockets on the pipe wall ( 18 ) of the skeletal element ( 16 ) are arranged so that the bendable section ( 12 ) controlled in different deflection directions is bendable. Medical instrument with a shaft tube ( 10 ) according to one of claims 1 to 7. Method for producing a shaft tube ( 10 ) according to one of the preceding claims, in which for the articulation of skeletal elements ( 16 ) of a bendable section ( 12 ) of the shaft tube ( 10 ) Rod ends ( 20 ) by means of at the pipe wall ( 18 ) of the skeletal elements ( 18 ) attached retaining tongues ( 24 ) against falling out of the rod ends ( 20 ) corresponding joint pans ( 22 ), characterized in that the method comprises the steps of: providing an elongated tube ( 34 ); Separating the pipe ( 34 ) in tubular skeletal elements ( 16 ) and incorporation of sockets ( 22 ) and rod ends ( 20 ) in the pipe wall ( 18 ) of the skeletal elements ( 16 ) and incorporating for the protruding arrangement of a retaining tongue ( 24 ) breakthroughs ( 30 ) in the tube wall of the skeletal elements ( 16 ); Inserting retaining tongues ( 24 ) in the breakthroughs ( 30 ) of the skeletal elements ( 16 ) and attachment of the retaining tongues ( 24 ) on the skeletal elements ( 16 ). Method according to claim 9, comprising the step of incorporating for fastening the retaining tongues ( 24 ) provided fastening pockets ( 36 ) in the tube wall of the elongated tube ( 34 ); Method according to one of claims 9 to 10, comprising the step of: incorporating for the tensile fastening of a pull wire end ( 14 ) holding troughs ( 38 ) in the tube wall of the elongated tube ( 34 ). Method according to one of claims 9 to 11, comprising the step of drawing in a pull wire ( 14 ) in at the retaining tongues ( 24 ) attached guide eyelets ( 32 ).

Images