Method for manufacturing an insertion tube of an endoscope and endoscope comprising an insertion tube

The invention relates to a method for manufacturing an insertion tube of an endoscope from a tubular element, wherein the insertion tube includes a proximal passive flexible portion and a distal deflecting portion, wherein, in the proximal passive flexible portion, cuts are provided to enable the proximal passive flexible portion to be bent. In the method, the cuts are configured in the proximal passive flexible portion such that adjacent cuts do not have the same distance. The invention further relates to an endoscope including such insertion tube.

The present invention relates to a method for manufacturing an insertion tube of an endoscope and to an endoscope comprising an insertion tube.

An endoscope is a device by which the interior of living organisms but also technical cavities can be examined. An important part of an endoscope is the flexible insertion tube. The requirements made to an insertion tube are high and diverse. On the one hand, it must be flexible so that it can be inserted into the human body. On the other hand, the insertion tube must exhibit specific rigidity. During examination, the physician must be able to push and rotate the insertion tube by means of the control body. Accordingly, the insertion tube must be so rigid that it is not kinked or twisted. Conventional insertion tubes therefore involve a very complex structure and high manufacturing costs to meet the afore-mentioned requirements.

For meeting all requirements, the insertion tube must have various characteristics. Three of the most important characteristics of an insertion tube are flexibility, torsional resistance and dimensional stability. It must be bendable, on the one hand, so that it can be inserted into the (e.g., human) body subject to examination. On the other hand, the insertion tube must have high torsional resistance to transmit the torque generated by the user by way of turning a control body, further to the distal end. Moreover, the insertion tube must not deform when it is bent or rotated.

The requirement that an insertion tube simultaneously must have the afore-mentioned characteristics is a technical contradiction in itself. An element is usually rigid and dimensionally stable when it has a high torsional resistance. When the element has a high flexibility, however, it has no high torsional resistance and is not dimensionally stable.

In order to satisfy the afore-mentioned requirement, developers have attempted for quite some time to design the base area of the insertion tube with plural components.FIG.25reveals a known way of structuring a base area of the insertion tube.

In the known solution ofFIG.25, three different components are joined to obtain the relevant characteristics of the base area of an insertion tube1000, viz. high flexibility, high torsional resistance and high dimensional stability.

A plastic coating1004is heated until the material of the inner face partially melts and penetrates gaps of a metal mesh1003. This combination imparts high torsional resistance and high flexibility to the base area of an insertion tube1000. However, the dimensional stability is still missing. Accordingly, two metal leaf spirals1001and1002arranged in opposite directions are used. Said metal leaf spirals1001and1002ensure the insertion tube to become dimensionally stable. Now the described combination imparts the three stated necessary characteristics to the insertion tube1000: namely high flexibility, high torsional resistance and high dimensional stability.

A drawback of this complex structure resides in the economic aspect. Three components are joined in an expensive manufacturing process. Both the materials and the manufacturing process incur high manufacturing costs.

It is the object of the present invention to provide a method for manufacturing an insertion tube of an endoscope as well as an endoscope comprising an insertion tube which are less complex and help reduce the costs.

As regards the method, the object is achieved by a method comprising the features of claim1. An endoscope comprising an insertion tube is illustrated in claim11. Advantageous developments are the subject matter of the dependent claims.

The invention is directed to a method for manufacturing an insertion tube of an endoscope from a tubular element. The insertion tube has a proximal passive flexible portion and a distal deflecting portion. In the proximal passive flexible portion cuts are provided to enable the proximal passive flexible portion to be bent. These cuts are configured in the proximal passive flexible portion such that adjacent cuts do not have the same distance from each other.

In the insertion tube according to the invention, cuts are produced that do not have the same distance. The distances between cuts produced in the insertion tube thus are different from each other. The cuts may be produced perpendicularly to the axis of the insertion tube.

In one example, when viewed in the longitudinal direction of the insertion tube, plural adjacent cuts can be produced so that a distance between first and second adjacent cuts is a predetermined distance and a distance between the second and third adjacent cuts is smaller or larger than the predetermined distance.

In another example, when viewed in the longitudinal direction of the insertion tube, plural adjacent cuts can be produced so that a distance between first and second adjacent cuts is a predetermined distance, and a distance between the second cut and a third adjacent cut is equal to the predetermined distance, but a distance between the third cut and a fourth adjacent cut is smaller or larger than the predetermined distance.

The different distances of the cuts result, in the longitudinal direction of the insertion tube, in regions having a large distance between the cuts and in regions having a small distance between the cuts. The region having a large distance between the cuts ensures high bending stability and high resistance to torsion. The region having a small distance between the cuts ensures high bendability and high flexibility. The exact dimensions for the distances can be selected as needed.

In the proximal passive flexible portion, main cuts may be provided which have the same distance from each other in the longitudinal direction of the proximal passive flexible portion, and, adjacent to the main cuts, secondary cuts may be provided in the proximal passive flexible portion which are arranged, in the longitudinal direction of the proximal passive flexible portion, to be closer to the adjacent main cuts on one side of the secondary cuts than to the adjacent main cuts on the other side of the secondary cuts.

The main cuts can be cut in parallel to each other.

The main cuts can be cut in an interrupted manner along the periphery of the proximal passive flexible portion so that non-cut stays are left between main cut portions located on a peripheral line.

The secondary cuts can be cut adjacent to a respective stay between main cut portions located on a peripheral line.

One secondary cut can be respectively cut in the longitudinal direction of the proximal passive flexible portion adjacent to the stay on one side of the stay.

Alternatively, two secondary cuts can be respectively cut in the longitudinal direction of the proximal passive flexible portion adjacent to the stay on both sides of the stay.

The main cuts can be cut to be wider than the secondary cuts.

The whole insertion tube can be manufactured including a connecting region of the proximal passive flexible portion at a control body, the proximal passive flexible portion, a transition region between the proximal passive flexible portion and the deflecting portion, and the deflecting portion from one single tubular element.

The whole insertion tube can be cut by laser.

In one example of the method, only one tubular element must be provided. A connecting operation between the proximal passive flexible portion and the distal deflecting portion is omitted. The production costs are lower than in previous methods for manufacturing an insertion tube.

In this method, the whole insertion tube including the deflecting portion can be cut by laser from one single tubular element. The laser machining allows for a high-precision design of the whole insertion tube.

In this method, individual cuts can be made in the tubular element. This renders manufacture easy and inexpensive.

In this method, the distal deflecting portion has inwardly bent guiding projections on which a pull cable is supported; wherein the inwardly bent guiding projections are cut out of the peripheral wall of the distal deflecting portion and then are bent inward. Thus, guides for a pull cable are produced in a simple manner on the inner peripheral side of the deflecting portion.

In this method, the insertion tube includes, at the transition from the proximal passive flexible portion and the distal deflecting portion, an inwardly bent tab on which a guide spring is supported; the inwardly bent tab being cut out of the peripheral wall of the insertion tube and then being bent inward. The number of the inwardly bent tabs on which a guide spring is supported corresponds to the number of guide springs and thus the number of pull cables. In this way, guides for guide springs are produced in a simple manner on the inner peripheral side of the insertion tube.

In this method, in the peripheral wall of the distal deflecting portion plural joints can be produced by cutting. Individual joints forming separate bodies and being positively connected to each other are produced in a simple and inexpensive manner.

In this method, the respective joint produced by cutting includes a coupling portion which is coupled to an adjacent joint produced by cutting such that an axial movement but no radial movement of the joints relative to each other is blocked, and a guiding portion engaged in an adjacent joint produced by cutting in such a manner that an axial movement of the joints relative to each other is possible. The coupling portion helps couple adjacent joints to each other and the guiding portion renders adjacent joints axially movable relative to each other.

In this method, the proximal passive flexible portion is produced by respective lateral incisions made perpendicularly to the longitudinal extension of the tubular element. Thus, the proximal passive flexible portion can be quickly and simply manufactured.

In this method, in the longitudinal extension of the tubular element, the proximal passive flexible portion has at least two sub-portions including the respective lateral incisions (cuts) at a distance different from each other in the longitudinal extension of the tubular element. Thus, plural separate sub-portions having different flexibility and bendability relative to each other can be formed in the proximal passive flexible portion.

In this method, the tubular element may be produced from stainless steel. The cuts can be easily produced. The material costs are low.

In this method, the tubular element can be produced from plastic material. Any suitable plastic material having sufficient strength may be employed. The plastic material merely must be capable of producing the bendability of the finished insertion tube.

In this method, a pull cable can be arranged from a control body disposed proximally from the proximal passive flexible portion on the inner peripheral side of the tubular element, which pull cable is guided on a most distally located joint of the distal deflecting portion through a first slit in a wall of the tubular element to the outer periphery of the tubular element, is guided around the outer periphery of the tubular element to a second slit in the wall of the tubular element to the inner periphery of the tubular element, with the second slit being opposed to the first slit by 180 degrees, and is returned to the control body on the inner peripheral side of the tubular element. In this way, an especially inexpensive anchoring of the pull cable on the distal side of the deflecting portion can be effectuated.

The endoscope according to the invention includes an insertion tube. The insertion tube includes a proximal passive flexible portion and a distal deflecting portion. In the proximal passive flexible portion cuts are provided to allow for bending of the proximal passive flexible portion. Adjacent cuts do not have the same distance in the proximal passive flexible portion.

In this endoscope, the proximal passive flexible portion can include main cuts which have the same distance from each other in the longitudinal direction of the proximal passive flexible portion, and the proximal passive flexible portion can include, adjacent to the main cuts, secondary cuts which are arranged, in the longitudinal direction of the proximal passive flexible portion, to be closer to the adjacent main cuts on one side of the secondary cuts than to the adjacent main cuts on the other side of the secondary cuts.

In this endoscope, the main cuts may be parallel to each other.

In this endoscope, the main cuts may extend along the periphery of the proximal passive flexible portion in an interrupted manner such that non-cut stays are left between main cut portions located on a peripheral line.

In this endoscope, the secondary cuts may be arranged adjacent to a respective stay between main cut portions located on a peripheral line.

In this endoscope, a secondary cut may be respectively arranged in the longitudinal direction of the proximal passive flexible portion adjacent to the stay on one side of the stay.

In this endoscope, alternatively two secondary cuts may be arranged in the longitudinal direction of the proximal passive flexible portion respectively adjacent to the stay on both sides of the stay.

In this endoscope, the main cuts may be wider than the secondary cuts.

In this endoscope, the whole insertion tube including a connecting region of the proximal passive flexible portion at a control body, the proximal passive flexible portion, a transition region between the proximal passive flexible portion and the deflecting portion, and the deflecting portion can be manufactured from one single tubular element.

In this endoscope, the whole insertion tube may be cut by laser.

Further, the whole insertion tube including the passive flexible portion and the deflecting portion may be formed of one single tubular element.

The distal deflecting portion may have inwardly bent guiding projections on which a pull cable is supported.

The insertion tube may include, at the transition from the proximal passive flexible portion and the distal deflecting portion, an inwardly bent tab on which a guide spring is supported.

Plural joints may be formed in the peripheral wall of the distal deflecting portion.

Each joint may include a coupling portion coupled to an adjacent joint such that an axial movement but no radial movement of the joints relative to each other is blocked, and a guiding portion engaged in an adjacent joint such that an axial movement of the joints relative to each other is enabled.

The tubular element may be manufactured from stainless steel or from plastic material.

From a control body disposed proximally from the proximal passive flexible portion a pull cable can be arranged on the inner peripheral side of the tubular element, which pull cable is guided at a most distally located joint of the distal deflecting portion through a first slit in a wall of the tubular element to the outer periphery of the tubular element, is guided around the outer periphery of the tubular element to a second slit in the wall of the tubular element to the inner periphery of the tubular element, with the second slit being opposed to the first slit by 180 degrees, and is returned to the control body on the inner peripheral side of the tubular element.

The afore-described aspects of the present invention can be combined in a suitable manner.

Hereinafter, the present invention shall be described in detail with reference to the drawings by way of embodiments.

FIRST EMBODIMENT

Hereinafter, with reference toFIGS.1to23, a first embodiment of the present invention shall be described.

First of all,FIG.1shows a schematic side view of an endoscope1to which the invention is applicable. As can be inferred fromFIG.1, such endoscope1includes an insertion tube2disposed on the distal side of a control body3. The control body3serves as operating unit of the endoscope1.

The insertion tube2is a cylindrical tube-shaped or hose-shaped structure.

Hereinafter, the insertion tube2is described in more detail in the direction in which it is inserted into a patient. The insertion tube2is inserted with the distal end ahead.

On the distal side, the insertion tube2has a distal deflecting portion A. The deflecting portion A can be laterally deflected by means of one or more control wires (control cable(s)) relative to the proximal part of the insertion tube2. The control wire or control cable (hereinafter only referred to as control wire) is supported inside the insertion tube2on an inner peripheral surface of the insertion tube2to be guided in the direction of extension of the insertion tube2.

The distal end of the control wire is anchored on the distal side of the deflecting portion A. The proximal end of the control wire is connected to a control element disposed in the control body3. Said control element tensions the control wire to bring about a desired deflection of the deflecting portion A.

Proximally from the deflecting portion A, the insertion tube2is designed as a flexible hose member forming a proximal passive flexible portion20. During insertion of the insertion tube2, the flexible portion20follows the deflecting portion A.

It is indicated inFIG.1that the flexible portion20is designed along its longitudinal direction in zones having different flexibility. For example, the flexible portion20has a first zone B, a second zone C and a third zone D, when viewed in the proximal direction. The first zone B forms a distal region, the second zone C forms a central region and the third zone D forms a proximal region.

In the fragmentary representation ofFIG.2, the third zone D is not shown.

For avoiding kinking between the deflecting portion A and the first zone B, the first zone B is preferably provided with the maximum flexibility among the zones of the flexible portion20. Since the first zone B is equipped with very high flexibility, there is no abrupt transition of flexibility between the deflecting portion A and the first zone B.

The second zone C has lower flexibility than the first zone B. The third zone D in turn has lower flexibility than the second zone C.

The insertion tube2according to the invention is formed of one piece. That is, there are not joined two elements at the transition from the deflecting portion A to the flexible portion20. Thus, the distal deflecting portion A and the proximal passive flexible portion20are formed with the three zones B, C and D of one single tube or hose.

On the proximal side, the insertion tube2is fixed at the distal end of the control body3. The insertion tube2can be fixed to the control body3, e.g., by a locking ring, a seal ring or directly. The insertion tube2may be glued or screwed, for example, to the control body3. The control body3includes a first control wheel F as first control element for controlling a control wire or cable and a second control wheel G as second control element for controlling a control wire or cable. The first control wheel F can deflect the deflecting portion A in a first plane by pulling a control wire or cable (e.g., toward the viewer and away from the viewer inFIG.1). The second control wheel G can deflect the deflecting portion A in a second plane perpendicular to the first plane by pulling a control wire or cable (e.g., upward and downward inFIG.1).

The deflecting portion A can be deflected, e.g., about 200-270 degrees. This is sufficient for most applications. In a special form, the deflecting portion A can be deflected even about 300 degrees.

In the following, the insertion tube2according to the invention and the manufacture thereof are described in greater detail.

The whole insertion tube2is formed of one single tubular element or hose member (hereinafter this is simply referred to as tubular element). The tubular element is a tube made from preferably relatively hard material. A tube made from stainless steel is especially preferred. However, also a tube made from hard plastic can be applied. On principle, any material applicable for medical purposes can be used.

In the tubular element cuts are provided by a laser cutting machine, as illustrated in detail further below. After providing the cuts, particular segments of the tubular element are bent as illustrated in detail further below. The manufacture of the base body of the whole insertion tube2requires no further process steps apart from providing cuts and bending. After that, the base body of the insertion tube2can be provided with a control wire and can be encased by a jacket element.

Hereinafter, the individual portions of the insertion tube2shall be described in detail.

The flexible portion20forms the proximal part of the insertion tube2according to the invention. The flexible portion20includes the three zones B, C and D each having different flexibility.

For clarity,FIG.1shows the proximal passive flexible portion20as if the three zones B, C and D were equal in length to each other along the longitudinal direction of the insertion tube2, which, of course, is not the case. The central zone C is longer than the transition region B and the connecting region D. Among the three zones B, C and D, the central zone C in the proximal passive flexible portion20is the longest one. In other words, the actual proximal passive flexible portion20is formed by the structure of the central region C. The bending characteristics, the elasticity and the torsional resistance of the proximal passive flexible portion20are materialized by the structure of the central region C.

Hereinafter, the structure of the central region C and thus of the actual proximal passive flexible portion20shall be described in detail by way ofFIGS.3to10.

FIG.3illustrates a fragmentary schematic side view of part of a proximal passive flexible portion of the insertion tube according to the invention of a first embodiment.

FIG.4illustrates a fragmentary perspective view of the part of proximal passive flexible portion ofFIG.3.

The cut design according to the invention of the first embodiment is evident fromFIGS.3and4.

When manufacturing said cut design, a tube2is used as raw material. The tube2has an axis and a longitudinal extension. The tube2consists of a sufficiently hard material. For example, stainless steel can be used. Plastic material or a nickel-titanium alloy such as Nitinol can equally be used. The tube2later constitutes the insertion tube according to the invention.

The tube2takes a shape which initially is not flexible. The tube2has high torsional resistance and high dimensional stability.

In this tube2, at predetermined distances H main cuts98are produced preferably by laser at the periphery in the peripheral direction. By peripheral direction a direction is meant which extends at right angles with the axis of the tube2. Along the tube2, the respective distance H is equal.

The main cuts98penetrate the thickness of the jacket of the tube2. The main cuts98extend in the peripheral direction of the tube2over approximately half a peripheral length. Thus, for each peripheral line two main cut portions98A,98B successive in the peripheral direction are produced. A stay97at which the material of the tube2is not cut is provided between the respective main cut portions98A,98B. When viewed in the longitudinal direction of the tube2, the region ahead of and behind (proximal and distal of) the respective main cut98is connected via the stay97. Thus, at each peripheral line for the main cut98there are provided two stays97. The two stays97are arranged to be diametrically opposed at each peripheral line for the main cut98. When viewed in the peripheral direction, a length of a main cut portion98A,98B plus a length of the stay97exactly is 180°. The length of the main cut portion98A and the length of the main cut portion98B are equal to each other.

The stays are offset with respect to each other about 90° from the main cut98to the next main cut98along the longitudinal direction of the tube2, as is evident fromFIGS.3and4.

In the longitudinal direction of the tube2, secondary cuts99are produced proximally and distally of each stay97. The secondary cuts99extend in parallel to the main cut portions98A,98B. The length of the secondary cuts99in the peripheral direction is longer than the length of the stay97in the peripheral direction. The length of the respective secondary cuts99is equal to each other.

In the longitudinal direction of the tube2, the distance N of each secondary cut99from its adjacent main cut portions98A,98B is smaller than the distance H of the main cuts98. Thus, a proximal secondary cut99and a distal secondary cut99are associated with each main cut98consisting of the two main cut portions98A,98B.

In the longitudinal direction of the tube2, the distance N of each secondary cut99from its adjacent main cut portions98A,98B is equally smaller than the distance M of each secondary cut99from its adjacent secondary cut99that is associated with the next main cut98, seeFIG.9.

The characteristic of the tube2changes by the main cuts98and secondary cuts99. The tube2becomes flexible. The flexibility and other characteristics of the tube2are strongly dependent, inter alia, on the design of the cuts98,99. More exactly speaking, the cut width, the cut length and the distances of the tube cuts are, inter alia (apart from the material), crucial factors that have an effect on the characteristics of the tube2.

In the region X, the cut design is provided which is responsible for the creation of the high flexibility of the tube2.

Hereinafter, the connection between the deformation and the distance between tube cuts during bending will be explained.

In its original shape without any cuts, a tube has a particular bending resistance. As soon as said tube is cut, the bending resistance decreases corresponding to the shape and the number of the cuts provided in the tube. The graphic representation inFIG.6illustrates the connection between the deformation and the distance between tube cuts when the tube is bent.

FIG.6shows the results of a bending simulation of a tube provided with cuts. The deformation of a tube provided with cuts during a bending operation is shown.

The double dot-and-dash line indicates the distance of a cut from its adjacent cut.

The continuous line indicates the deformation of the tube during bending.

Each of the ordinate and the abscissa show length units (e.g., mm).

The following is visible fromFIG.6: The larger the distance between the tube cuts, the larger the bending resistance becomes (the lower the deformation becomes). If the distance between the tube cuts become infinite, the tube2reaches its originally maximum bending resistance.

Since low bending resistance (and thus high flexibility) is required for an insertion tube of an endoscope, consequently a distance between the tube cuts must be as small as possible.

In accordance with the invention, the region X is designed such that the cuts98and99are close to each other (small distance N) and four spring-type portions F1, F2, F3and F4are formed. If the cut tube2is bent, the portions F1, F2, F3and F4are stretched and a spring-type counter-force is thus resulting. If the tube2is relieved after bending, the counter-force acts upon the tube2so that the latter recovers its linear shape. Along the longitudinal direction of the tube2, this design of the region X is repeatedly offset by 90°, namely along the entire length of the proximal passive flexible portion C of the tube2. In this way, the tube2is evenly flexible in all directions.

FIG.7shows the region X as an enlarged detail. In the design of a main cut98composed of a first main cut portion98A and a second main cut portion98B with the associated secondary cuts99in the region X, the distance N between the main cut portions98A,98B and the associated secondary cuts99is intended to be as small as possible to create high flexibility.

Hereinafter, the torsional resistance shall be explained by way of a tube.

FIG.8illustrates a connection between the deformation and the distance between tube cuts during bending with regard to the torsional resistance. In other words, the graphical representation ofFIG.8illustrates the connection between the deformation and the distance between tube cuts if the tube is twisted.

FIG.8shows the results of a twist simulation of a tube provided with cuts. The deformation of a tube provided with cuts during a twisting operation is shown.

The broken line indicates the distance of a cut from its adjacent cut.

The continuous line indicates the deformation of the tube during twisting.

Each of the ordinate and the abscissa indicates length units (e.g., mm).

The following is evident fromFIG.8: A tube in its original shape without cuts has a particular torsional resistance. As soon as said tube is cut, the torsional resistance decreases corresponding to the shape and the number of the cuts. The larger the distance between the tube cuts, the larger the torsional resistance becomes (and the smaller the deformation becomes during rotation). If the distance between tube cuts becomes infinite, the tube reaches its originally maximum torsional resistance.

Since high torsional resistance is required for an insertion tube of an endoscope, the distance between tube cuts consequently is intended to be as large as possible.

FIG.9illustrates in a region Y in an enlarged detail the distance M of each secondary cut99from its adjacent secondary cut99which is associated with the next main cut98.

The design in the area Y shows that the distance M between adjacent secondary cuts99is intended to be as large as possible to create high torsional resistance. The exact distance M between adjacent secondary cuts99can be determined as individually required.

Hereinafter, achieving the dimensional stability on the tube2shall be explained.

A hard tube is naturally dimensionally stable. The region Y is designed so that the tube2maintains the dimensional stability after it has been provided with a plurality of cuts98,99.

The secondary cuts99are arranged at such a large distance here that the region Y is relatively long in the longitudinal direction of the tube2. In other words, a wide annular region that is free from cuts forms in the region Y.

The region Y can be regarded as a short tube and therefore has high dimensional stability. If the entire tube2is bent, the portions F1, F2, F3and F4will yield (will give way), because the region Y has an inherent stability.

The tube2thus is flexible and at the same time dimensionally stable.

Hereinafter, the interaction of the regions X and Y shall be explained.

The entire design of the proximal passive flexible portion C is a combination between the regions X and Y.

Each of said regions X and Y imparts a particular characteristic to the tube2.

In the region X, the main cuts98and the secondary cuts99are arranged closely to each other to achieve high flexibility.

In the region Y, however, the secondary cuts99have a larger distance from each other to achieve high torsional resistance.

This results in the following interactions between the region X and the region Y:

In the region Y, the secondary cuts99have a large distance from each other. This region Y thus is stable both during bending and during twisting. During bending, the region Y remains almost unchanged. The region X, on the other hand, yields and defines the flexibility of the entire tube2. The effect of the region Y on the flexibility of the tube2is insignificant.

In the region X, the main cuts98and secondary cuts99are arranged very closely to each other.

In the embodiment, the main cuts98and the secondary cuts99have a cutting width different from each other. By cutting width the width of the respective cut in the longitudinal direction of the tube is meant. If the main cuts98and the secondary cuts99are produced by laser, the cutting width is adjusted by selecting the diameter of the emitted laser beam.

The cutting width of the secondary cuts99is intended to be kept as small as possible. By means of a laser a cutting width, e.g., of far less than 20 μm can be provided. For example, the secondary cuts99can be produced to have a cutting width of 20 μm. The main cuts98can be produced to have a cutting width of 0.2 mm, for example. These values of the cutting width are merely examples. The appropriate cutting widths can be established by tests. Preferably, the cutting width of the main cuts98is larger than the cutting width of the secondary cuts99. For example, the cutting width of the main cuts98may be ten times the cutting width of the secondary cuts99. This value, too, is merely an example. The appropriate factor may be adjusted as required. The invention is not limited to these values.

Under torsional stress the tube2is loaded with a torsional moment Mt acting around the longitudinal axis of the tube2. By the impact of the torsional moment, imaginary longitudinal lines L of the tube2extending in parallel to the longitudinal axis will deform helically, as shown inFIG.10. Since the distance N of the main cuts98and secondary cuts99is very small in the region X, the deformation of the region X will differ only slightly from that of the region Y. The torsional resistance of the region Y defines the torsional resistance of the entire tube2. The impact of the region X on the torsional resistance of the tube2is insignificant.

By producing cuts having distances different from each other as afore-described, in the proximal passive flexible portion C of the tube2both high flexibility and high torsional resistance can be achieved.

Thus, the endoscope tube2according to the invention is bendable in the proximal passive flexible portion C of the flexible portion20with high flexibility as well as with high torsional resistance laterally to the longitudinal axis thereof.

The individual zones B, C and D in the flexible portion20differ by the distances H of the cuts98in the longitudinal direction and thus the density of the cuts98being differently configured.

In the zone B, the distance H of the cuts98is minimum. Thus, in the zone B the density of the cuts98is maximum.

In the zone C, the distance H of the cuts98is larger than in the zone B. In the zone D the distance H of the cuts98is larger than in the zone C.

Consequently, the flexibility and the bendability are higher in the zone B than in the zone C. Furthermore, the flexibility and the bendability are higher in the zone C than in the zone D. In other words, the flexibility and the bendability of the respective zones decrease at the flexible portion20in the proximal direction.

The zone D is provided, on the proximal side, with a region that is not provided with cuts. This region forms a transition to the control body3.

Transition from the deflecting portion A to the flexible portion20

The transition region from the deflecting portion A to the flexible portion20is indicated as region K inFIG.2. The deflecting portion A ends in said region K. In other words, the most proximally located first member of the deflecting portion A is located distally from the region K.

As shown inFIGS.2,11and12, in said region K the wall surface of the tubular element is cut by a cut70in the form of an inverse letter C. In other words, the cut70is cut in the tubular element in the form of an incomplete circle. The circle of the cut70is not cut through on the distal side, as can be seen fromFIG.11. The distal side of the cut70which is not cut through forms a hinge71for a tab72. The tab72has a lower ear73, an upper ear74and a tab centerpiece75. The lower ear73abuts against an upper side of the tab centerpiece75. The upper ear74abuts against a lower side of the tab centerpiece75.

The tab72is manufactured as follows. The location of the cut70is set. In the middle of the cut70, a hole77is cut. The cut70is formed by laser as shown inFIG.2. The tab centerpiece75is supported from the rear, i.e., from the inside of the tubular element by a punch. The lower ear73is bent inwardly by 90 degrees relative to the tab centerpiece75. The bending line of the ear73relative to the tab centerpiece75extends in parallel to the axis of the tubular element (inFIGS.2and4in the direction pointing to the left and the right). The upper ear74is equally bent inwardly by 90 degrees relative to the tab centerpiece75. The bending line of the ear74relative to the tab centerpiece75also extends in parallel to the axis of the tubular element. After that, the tab centerpiece75is bent inwardly by 90 degrees. The bending line of the tab centerpiece75relative to the tubular element extends in the vertical cutting plane to the axis of the tubular element (inFIGS.2and11in the direction pointing upward and downward). In other words, the tab centerpiece75is bent inwardly by 90 degrees at the hinge71. The tab centerpiece75is bent inwardly especially until a distal lateral edge of the lower ear73and a distal lateral edge of the upper ear74abut against the inner periphery of the tubular element (seeFIG.12).

The tab72serves as a support for a guide spring8. In particular, the proximal surface of the tab centerpiece75forms a stop surface for the distal end of the guide spring8. The two ears73,74support the tab centerpiece75and absorb compressive forces acting from the guide spring8and forward them to the inner peripheral surface of the tubular element.

The tab centerpiece75has the centric hole77. The hole77has a larger diameter than a control wire and a smaller diameter than the guide spring8. The control wire is guided in the flexible portion20within the guide spring8and passes through the hole70and extends further into the deflecting portion A.

In the region K, tabs72are provided in the number of the control wires used (in the present embodiment: four). The tabs72are evenly spread in the peripheral direction of the tubular element.

Deflecting Portion A

The precise structure of the deflecting portion A is illustrated inFIGS.13to18.

The deflecting portion A includes individual joint members6arranged in the longitudinal direction of the deflecting portion A. The individual joint members6are pivoting relative to each other. InFIGS.13and14, three successively arranged joint members6are shown: a joint61, a joint62proximally from the joint61and a joint63proximally from the joint62.

The joint members6are equally designed except for the most distally located joint member6and the most proximally located joint member6.

The structure of the respective joint member6will be discussed below by way of the joint member62.

The joint member62is formed as a tubular portion of said tubular element by laser-cutting. The joint member62has distal boundary lines601,602,603,604and605and proximal boundary lines606,607,608and609at the periphery of the tubular element.

The individual distal boundary lines are composed of one circularly shaped head line601, two neck lines602, two shoulder lines603, two arm lines604and one arm end line605. More exactly speaking, the distal side of the joint member62is formed as follows. The circularly shaped head line601forms an incomplete circle which merges at the proximal side on each side into a neck line602. A shoulder line603which extends approximately perpendicularly to the axis of the tubular element is connected to each of the two neck lines602. An arm line604which extends approximately in parallel to the axis of the tubular element in the distal direction is connected to each of the two shoulder lines603. The two distal ends of the arm lines604are connected by an arm end line605which again extends perpendicularly to the axis of the tubular element.

Hence the joint member62includes a main body621from which each of a first head622, a first arm623, a second head622and a second arm623protrudes to the distal side about 90 degrees along an imaginary peripheral line extending perpendicularly to the axis of the joint member62. Thus, the heads622,622extend in a first imaginary plane. The arms623,623extend in a second imaginary plane that is offset by 90 degrees against the first imaginary plane. The two heads622,622of the joint member62form a pivot axis for the joint member62located distally therefrom.

Each head622is formed on the distal side by a head line601. A constriction is formed by the neck lines602between the head622and the main body621. The respective head622protrudes further in the distal direction than the respective arm623.

The individual proximal boundary lines are composed of one curved foot line606, two bottom lines607, two straight foot lines608and one waist line609. More precisely, the proximal side of the joint member62is formed as follows. The curved foot line606forms an incomplete circle that is open on the proximal side. At the open ends of the incomplete circle, the curved foot line606merges into each of the bottom lines607extending approximately perpendicularly to the axis of the tubular element.

A straight foot line608which extends approximately in parallel to the axis of the tubular element in the distal direction is connected to each of the two bottom lines607. The two distal ends of the straight foot lines608are connected by a waist line609which in turn extends perpendicularly to the axis of the tubular element.

In this way, on the proximal side of the main body621the joint member62includes two feet624extending in the proximal direction. Each of the feet624has, in the direction of extension, a straight side at the straight foot line608and a curved side at the curved foot line606.

In the region between the two straight foot lines608, an arm of the proximally located joint member63is arranged to be movable in the longitudinal direction. In the region between the two curved foot lines606, a head of the proximally located joint member63is fixedly held in the longitudinal direction. Only a slight movement due to play between the inner periphery of the curved foot line and the outer periphery of the circularly shaped head line is possible.

In the non-curved state of the deflecting portion A, the waist line609is spaced apart from the arm end line605of the proximally located joint member63, as shown inFIG.14. The arm end line605and the waist line609of the proximally located joint member63are parallel to each other.

In the non-curved state of the deflecting portion A, the bottom line607is spaced apart from the shoulder line603of the proximally located joint member63, as shown inFIG.14. The bottom line607and the shoulder line603of the proximally located joint member63may be in parallel to each other or approximately in parallel to each other or else slightly angled relative to each other, as shown inFIG.14. Between the bottom line607and the shoulder line603of the proximally located joint member63, not only a simple cut line has been produced, but the material of the tubular element has been cut out as a quadrangular piece.

A respective head622forms a coupling portion that is coupled to an adjacent joint member6. The feet624constitute a guide portion engaged in an adjacent joint member6such that an axial movement of the joint members6relative to each other is possible.

FIG.17illustrates a top view onto the deflecting portion A comprising the respective joint members6. In the top view, the heads622of the joint members6are visible.

FIG.18illustrates a side view of the deflecting portion A comprising the respective joint members6. In the side view, the feet624of the joint members6are visible.

The most distally located joint member6includes no head and is shown in theFIGS.2and17to21.

The most proximally located joint member6includes no foot and is shown in theFIGS.2,11and18.

In the embodiment, the deflecting portion A can be deflected in two deflecting directions, i.e., upward and downward in theFIGS.13and14(andFIG.17), wherein the respective heads622of the joint members6form bending axes of the joint members6. In other words, the deflecting portion A inFIG.17is upwardly and downwardly pivotable. In the representation ofFIG.18, the deflecting portion A is pivotable toward the viewer and away from the viewer.

As illustrated inFIGS.15and16, the waist line609forms a hinge portion for a cable guide tab630. The cable guide tab630extends from the waist line609. A material portion extending along the straight foot lines608to the arm end line605of the proximally located joint member63is used for the cable guide tab630. The cable guide tab630is articulated to the waist line609and is curved inwardly about 90 degrees. The cable guide tab630includes a centric hole631. The hole631has a larger diameter than the control wire.

Each of the joint members6includes the cable guide tabs630including the hole631such that the cable guide tabs630for a specific control wire are arranged successively in the longitudinal direction of the deflecting portion A. The cable guide tabs630serve as guide projections on which a control wire is supported. Thus, the cable guide tabs630guide the associated control wire through the deflecting portion A.

The joint members6may be arranged on the deflecting portion A so that their heads face the proximal direction, as shown inFIG.17. Alternatively, the joint members6may be arranged on the deflecting portion A so that their heads face the distal direction, as indicated inFIG.13.

The distal end of the deflecting portion A is shown inFIGS.19to21. InFIGS.19to21, the most distally located joint member69of the deflecting portion A is visible. In this most distally located joint member69, the distal side of the control wire9is anchored. The control wire9extends from the control body3to the most distally located joint member69of the deflecting portion A.

Fastening of the Control Wire

The precise fastening of the control wire9is illustrated inFIGS.22and23.

The control wire9is fastened to the control wheel G in the control body3. When the control wheel G is rotated in a tensioning direction, the control wire9is tensioned. When the control wheel G is rotated in the relieving direction opposite to the tensioning direction, the control wire9is relieved.

The control wire9extends from the control body3extending in the insertion tube2toward the joint member69and forms a first portion91. Said first portion91of the control wire9extends along the inner periphery of the insertion tube2. Said first portion91of the control wire9is shown by way of the reference numeral91inFIG.22. On the distal side of the joint member69, a slit691penetrating the peripheral wall of the joint member69is configured (seeFIG.20) which slit extends in the longitudinal direction of the joint member69. Another similar slit692is provided on the distal side of the joint member69and is diametrically opposed to the slit691.

The control wire9extends along the inner periphery of the joint member69in the distal direction and penetrates the slit691to the outside, is wound at the outer periphery of the joint member69in the peripheral direction of the joint member69to the slit692, penetrates the slit692to the inside and extends along the inner periphery of the joint member69in the proximal direction to the control wheel G in the control body3.

Consequently, the control wire9is divided into a first portion91extending from the control wheel G within the control body3to the slit691, a second portion92extending from the slit691at the outer periphery of the joint member69in the peripheral direction of the joint member69to the slit692, and a third portion93extending from the slit692to the control wheel G in the control body3.

By rotation of the control wheel G in the tensioning direction, the control wire9is tensioned and thus the deflecting portion A is deflected, as the third portion93anchored on the joint member69is urged in the proximal direction. The third portion93of the control wire9thus constitutes a distal anchoring portion of the control wire9.

Manufacturing Method

The insertion tube2according to the invention can be manufactured by one single tubular element which is cut by laser. The tubular element is made from a relatively hard material such as, e.g., stainless steel or else suitably hard plastic material. The initially hard tubular element is made flexible by the cuts, although it retains its rigidity.

The cuts produce the respective lateral incisions (cuts extending perpendicularly to the axis)98,99in the proximal passive flexible portion20, the hole77, the cut70in the transition region K, the hole631, the respective joint members6in the distal deflecting portion A and the slits691,692. This order is not meant to be a limitation. For example, the slits691,692may be cut before the joint members6. Moreover, the order of the cuts may also be reversed.

The flexibility as well as the rigidity of the tubular element can be controlled by way of the shape, the arrangement and the size of the cuts.

The location of the respective cuts can be calculated in advance and predetermined. In a programmable laser cutter, the predefined data for the respective cuts can be entered to automatically produce the insertion tube2.

The individual joint members6are completely cut out and form bodies physically separated from each other which are merely connected by form fit.

After laser-cutting of the tubular element, the tabs72and the cable guide tabs630are inwardly bent. Thus, the blank for the insertion tube2is finished.

Now the control wire9can be inserted and fastened in said blank for the insertion tube2. The blank for the insertion tube2can be fastened to the control body3. Further, a coating surrounding the blank for the insertion tube2and preferably being made from metal for shielding the electric control and onto said coating an elastic jacket made from plastic or rubber can be mounted onto the blank for the insertion tube2. The elastic jacket of plastic or rubber can be subjected to thermal shrinking.

SECOND EMBODIMENT

Hereinafter, a second embodiment of the present invention will be described with reference toFIG.24.

FIG.24illustrates a fragmentary schematic representation of the proximal passive flexible portion that is applied in the second embodiment.

The proximal passive flexible portion20structured according to the principle shown inFIG.24can replace the proximal passive flexible portion20of the first embodiment. In other words, the control body3and the deflecting portion A can be combined with the proximal passive flexible portion20of the present second embodiment.

As afore-described, the distal deflecting portion A and the proximal passive flexible portion20having the three zones B, C and D are formed of one single tube or hose, see alsoFIG.1.

Zone B constitutes a transition region B between the central region C and the deflecting portion A. Zone C constitutes the central region C. Zone D constitutes a connecting region D of the proximal passive flexible portion20at the control body3. In other words, the entire insertion tube including the connecting region D at the control body3, the central region C, the transition region B between the central region C and the deflecting portion A, and the deflecting portion A is manufactured from one single tubular element.

For clarity,FIG.1shows the proximal passive flexible portion20as if the three zones B, C and D were equal in length relative to each other along the longitudinal direction of the insertion tube2, which is not the case, of course. The central region C is longer than the transition region B and the connecting region D. The central region C is longest in the proximal passive flexible portion20. In other words, the actual proximal passive flexible portion20is formed by the structure of the central region C. The bending characteristics, the elasticity and the torsional resistance of the proximal passive flexible portion20are materialized by the structure of the central region C.

Hereinafter, the structure of the central region C of the proximal passive flexible portion20will be described in detail by way ofFIG.24.

The proximal passive flexible portion20is manufactured from the already afore-described tubular element. In the central region C, a plurality of main cuts990are cut along the longitudinal direction of the tubular element by laser-cutting. These main cuts990extend in parallel to each other. The main cuts990extend perpendicularly to the axis of the tubular element.

More precisely, the main cuts990extend along the periphery of the central region C in an interrupted manner so that non-cut stays992are left between main cut portions located on a peripheral line. In the present embodiment, four main cut portions are configured, when viewed in the peripheral direction.

FIG.24illustrates said main cut portions more precisely.FIG.24shows a first sequence of main cut portions formed in the peripheral direction denoted with the reference numerals990A,990B and990C. Moreover,FIG.24shows a second sequence of main cut portions formed in the peripheral direction denoted with the reference numerals990A1and990B1. The first sequence of main cut portions with the reference numerals990A,990B and990C is adjacent in the longitudinal direction to the second sequence of main cut portions formed in the peripheral direction with the reference numerals990A1and990B1. The length of the main cut portions in the peripheral direction is always the same. That is, not only is the length of the main cut portions in the peripheral direction of a particular sequence of main cut portions equal to each other, but the length of the main cut portions in the peripheral direction of all sequences of main cut portions in the entire central region C is equal to each other.

In the first sequence of main cut portions shown inFIG.24a first main cut portion990A, a second main cut portion990B and a third main cut portion990C are shown. A fourth main cut portion that is not visible is located on the side of the tubular element remote from the viewer behind the plane of projection. The first main cut portion990A, the second main cut portion990B, the third main cut portion990C and the fourth main cut portion that is not shown are configured successively in the peripheral direction of the tubular element. Thus, the tubular element is cut at said peripheral line four times in portions of equal length. A respective stay992is left between an end of the first main cut portion990A and a beginning of the second main cut portion990B, an end of the second main cut portion990B and a beginning of the third main cut portion990C, an end of the third main cut portion990C and a beginning of the fourth main cut portion (not shown), and an end of the fourth main cut portion (not shown) and a beginning of the first main cut portion990A. The tubular element is not cut at this region of the stay992.

In the second sequence of main cut portions shown inFIG.24, a first main cut portion990A1and a second main cut portion990B1are shown. A third main cut portion (not visible) and a fourth main cut portion (not visible) are located on the side of the tubular element remote from the viewer behind the plane of projection.

The main cut portions of the second sequence are arranged to be offset relative to the main cut portions of the first sequence. The region of the first sequence, where the main cut portions990A,990B and990C leave the respective stay992, in the adjacent second sequence corresponds to a region that forms the center of the main cut portion990A1and990B1, when viewed in the peripheral direction of the tubular element. The stays are thus positioned to be offset by 45 degrees from sequence to sequence of the main cuts990in the longitudinal direction of the tubular element.

The cutting width of all main cuts990in the tubular element is equal. The distance of all sequences of the main cuts990in the tubular element is equal to each other.

In the longitudinal direction of the tubular element, a respective secondary cut991is provided adjacent to each stay992, as shown inFIG.24.

On both sides in the longitudinal direction of the tubular element, a secondary cut991is configured adjacent to the stay992. The secondary cut991is shorter than the main cut990. The secondary cut991overlaps the ends of the adjacent main cuts990.

All of the secondary cuts991have the same length relative to each other in the peripheral direction of the tubular element. All of the secondary cuts991are in parallel to each other as well as in parallel to the main cuts990.

Each sequence of secondary cuts991is associated with a sequence of main cuts990adjacent to both sides in the longitudinal direction of the tubular element. In other words, each sequence of main cuts990has a proximal sequence of secondary cuts991and a distal sequence of secondary cuts991.

Consequently, when viewed along the longitudinal direction of the tubular element, a sequence of main cuts990is followed by a distal sequence of secondary cuts991which in turn is followed by a proximal sequence of secondary cuts991of the next sequence of main cuts990. When viewed along the longitudinal direction of the tubular element, a sequence of secondary cuts991on one side has a neighboring further sequence of secondary cuts991and on the other side has a neighboring sequence of main cuts990.

The secondary cuts991are configured in the longitudinal direction of the tubular element closer to the next main cuts990than to the next secondary cuts991.

In other words, adjacent to the main cuts990, secondary cuts991are provided such that they are arranged to be closer to the adjacent main cuts990than to the adjacent secondary cuts991.

For the purpose of illustration,FIG.24shows the secondary cuts991for the first sequence of main cut portions as secondary cuts991aand the secondary cuts991for the second sequence of main cut portions as secondary cuts991b. The secondary cuts991afor the first sequence of main cut portions are arranged to be closer to the adjacent main cut portions990A,990B and990C than to the adjacent secondary cuts991b. Thus, adjacent cuts in the tubular element do not have the same distance.

The cutting width of all secondary cuts991in the tubular element is equal. The cutting width of the secondary cuts991is narrower than the cutting width of the main cuts990.

Effect of the Second Embodiment

As in the first embodiment, the structure of the second embodiment ensures an insertion tube2with very high flexibility and, at the same time, high torsional resistance.

Further Alternatives

In the first and second embodiments, the flexible portion20includes, when viewed in the proximal direction, a first zone B, a second zone C and a third zone D of different flexibility. The number of zones or regions of different flexibility is not limited. The flexible portion20may also include more or fewer zones of different flexibility. The invention is also applicable to an insertion tube in which the flexible portion20has a continuously constant flexibility.

In the first and second embodiments, the tubular element of the insertion tube2is made from stainless steel. The invention is not limited thereto. The material of the insertion tube2may be any sufficiently rigid material such as rigid plastic material. In another alternative, Nitinol (a nickel-titanium alloy) can be used as tube material. This material has, inter alia, the characteristic of a so-called super-elasticity, i.e., it can be elastically deformed in large areas without being permanently bent.

In the first and second embodiments, cuts are provided in the tubular element by a laser cutter. Said cuts may be very precisely provided. Therefore, manufacture by laser is preferred. Basically, it is imaginable, however, that said cuts are also produced by other manufacturing processes such as sawing, wire sawing, etc.

In the first and second embodiments, the deflecting portion A can be deflected into two deflecting directions, viz. upward and downward inFIGS.6and7. In an alternative, the individual joint members6may be configured such that their heads622are offset from joint member6to joint member6, being rotated about 90 degrees about the axis of the deflecting portion A (axis of the joint members6). In this alternative, the deflecting portion A can be deflected into four deflecting directions, viz. upward and downward inFIGS.6and7as well as toward the viewer and away from the viewer.

In the alternative in which the deflecting portion A can be deflected into four deflecting directions, two control wires9can be used which extend inside the insertion tube2being offset by 90 degrees against each other. The joint member92then is provided with four distal slits which are equally offset by 90 degrees against each other.

In the embodiment, a respective joint member6is configured in the described form. The invention is not limited to the form of the joint member6. It is sufficient when joint members which are coupled to each other and allow for a deflecting movement of the deflecting portion A are cut in the deflecting portion A.

The proximal passive flexible portion C structured according to the principle shown inFIG.24can be applied to the first or second embodiment. This means that the proximal passive flexible portion C shown inFIG.24forms part of the integral tubular element for the entire insertion tube20. The tubular element for the entire insertion tube20including the proximal passive flexible portion C is thus manufactured from a tubular element by laser-cutting.

As an alternative, in the first or second embodiment the proximal passive flexible portion C can be manufactured separately from the remaining insertion tube20.

In the embodiment ofFIG.24, in the longitudinal direction of the tubular element two respective secondary cuts are disposed adjacent to the stay on both sides of the stay. In one alternative, in the longitudinal direction of the tubular element a respective secondary cut may be arranged adjacent to the stay on one side of the stay.

In the first embodiment, the main cuts are provided so that, along the periphery of the tubular element, two stays remain between the main cut portions.

In the second embodiment, the main cuts are provided so that, along the periphery of the tubular element, four stays remain between the main cut portions.

The invention is not limited thereto. Preferably, the number of stays along the periphery of the tubular element between the main cut portions is at least two or more and may be any number.

In the first embodiment, the cutting width of the main cuts98is larger than the cutting width of the secondary cuts99. In the second embodiment, too, the cutting width of the main cuts may be larger than the cutting width of the secondary cuts. The principle of the invention is also applicable to a case, however, in which the cutting width of the main cuts is equal to the cutting width of the secondary cuts.

The invention can be advantageously applied to a duodenoscope, a gastroscope, a colonoscope or similar endoscope. The principle of the invention can also be applied to any other type of endoscope.

The principle of the invention is also applicable to other medical devices which make use of an insertion tube.

LIST OF REFERENCE NUMERALS

1endoscope2insertion tube, pipe3control body6joint member8guide spring9control wire20flexible portion61joint member62joint member63joint member69most distally located joint member70cut71hinge72tab73lower ear74upper ear75tab centerpiece77hole91first portion of control wire92second portion of control wire93third portion of control wire97stay98main cut99secondary cut201cut from the top202cut from the bottom203non-cut clearance204cut from the side601head line602neck line603shoulder line604arm line605arm end line606curved foot line607bottom line608straight foot line609waist line621main body622head623arm624foot630cable guide tab631centric hole691slit692slit801cut from the top802cut from the bottom803non-cut clearance805annular portion including short cuts811short cut from the top812short cut from the bottom880cable guide tab990main cut991secondary cut992stay1000insertion tube1001metal leaf spiral1002metal leaf spiral1003metal mesh1004plastic coatingA deflecting portionA′ deflecting portionB first zone (distal region)C second zone (central region)D third zone (proximal region)F first control wheel (first control element)G second control wheel (second control element)H distanceJ control body housingK transition regionL longitudinal line of the tube2M distanceN distanceX region responsible for the creation of high flexibility of the tube2Y region responsible for the creation of high torsional resistance of the tube2