Endoscope with a tool

An endoscope having a handle with a handle housing arranged at a proximal end of the endoscope and an insertion tube extending from said handle and terminating in a tip part of a bending section at the distal end of the endoscope, the bending section comprises a distal tubular end segment and a plurality of articulated bending segments, the bending section comprises an intermediate segment between the proximal distal end segment and the plurality of articulated bending segments, wherein the intermediate segment is longer than a bending segment and the distal end segment.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a § 371 application of International Application Number PCT/DK2016/050154, filed May 26, 2016, which claims priority from Denmark Patent Application Number PA 2015 70322, filed May 27, 2015, both applications incorporated herein by reference in their entirety.

The present invention relates to an endoscope, in particular but not exclusively a disposable camera endoscope, having an operating handle arranged at a proximal end thereof and an insertion tube extending from said handle towards a distal end of the endoscope.

In general an endoscope comprises an operating handle at the proximal end and an insertion tube extending from the handle towards the distal end. The handle is adapted to be held by an operator and inter alia comprises externally protruding operating members connected to internal control means allowing the operator to control the movement of a bending section at the distal end of the insertion tube, while advancing the distal end of the insertion tube to a desired location e.g. within a body cavity of a person. By means of an attached monitoring device, such as a monitor with a display screen, the location to which the distal end has been advanced may be inspected using the endoscope. Often, however, inspection is not all that is desired, e.g. where the inspection is to locate the site for further actions. One such action could be the removal of an implanted stent, which necessitates the use of a tool.

In this respect WO2013/071938A1 discloses an endoscope with a built in tool in the form of a hook adapted to grip e.g. an urological stent, which can then be removed by retracting the endoscope. The endoscope is adapted for single handed use by an operator using the thumb to control the movement of the distal tip of the endoscope, and the index finger to control the reciprocating movement of the tool. The built in tool, however, does not allow other actions than gripping. The tool is controlled in a separate channel as compared to the working channel, through which fluid may be extracted or infused, or through which other tools may be inserted. Moreover, the full activation of the tool requires a reciprocating movement both out and in of the tip part of the bending section of the insertion tube of the endoscope. Given that stereoscopic vision is not available because only a single camera is used, it may be difficult for an operator to efficiently complete this reciprocating movement in a correct manner.

It is a further object of the present invention to provide an endoscope allowing the simultaneous control of the more complex actions of the integrated tool as well as the control of the bending section at the distal end of insertion tube of the endoscope using a single hand only.

It is a further object of the present invention to provide an endoscope allowing the simultaneous control of the more complex actions of the integrated tool during all operating conditions of the distal end of the insertion tube.

According to a first aspect of the invention this object is achieved by an endoscope having a handle with a handle housing arranged at a proximal end of the endoscope and an insertion tube extending from said handle and terminating in a tip part of a bending section at the distal end of the endoscope, the bending section comprises a distal end segment and a plurality of articulated bending segments, said endoscope further comprising a first operating member at the handle housing for controlling the bending section, a working channel extending within said insertion tube and having a distal end and a proximal end, a motion transfer member extending within said working channel and adapted to operate a retractable tool at an exit port of the distal end of the working channel at the tip part in response to the activation of a further operating member at the handle housing, the bending section comprises an intermediate segment between the distal end segment and the plurality of articulated bending segments, wherein the intermediate segment is longer than a bending segment.

The provision of an intermediate segment allows accommodation and protection of at least a part of the motion transfer member or the tool so that the tool may be released from the exit port and retracted properly under all operating conditions of both the tool and the distal top. Hence the endoscope may be operated without impairing operation of the tool or the bending radii. This is advantageous for all kinds of tools that may be envisaged to be used in combination with the invention, i.e. different tool types such as a pair grasping forceps, plyers, a needle, a stylet-cannula unit to carry out biopsies, brushes and scissors etc. Thereby the tool may be protected from being bend during operating of the bending section, i.e. during bending of the articulated bending segments in order to control the tip part, or to get stuck because it is protected in a part of the bending section where the working channel is not bended.

In a practically preferred embodiment the distal end segment is longer than a bending segment.

In a further practical embodiment which is especially advantageous for use in combination with a pair of grasping forceps, a distal end of said motion transfer member comprises a rigid tube section, which is more rigid than the rest of the motion transfer member. The intermediate segment ensure that the distal rigid tube section is not positioned in the articulated bending segments where it would be captured and difficult to release from the exit port at large bending radii.

In a practical embodiment that allows for improved bending properties of the articulated bending segments, the motion transfer member comprises a inner motion transfer member and an outer motion transfer member.

In a further practical embodiment that reduces friction between movable parts of the endoscope, the working channel is formed by a tube that comprises at least a first proximal section and a second distal section with a first connecting transition connecting the two sections, the second section has a higher degree of flexibility than the first section, and said outer motion transfer member comprises at least two sections differing from each other in rigidity and with a second connecting transition connecting the two sections, wherein the first connecting transition and the second connecting transition are staggered with respect to each other along the length of the insertion tube.

In yet another practical embodiment the movement of the first operating member is limited by the interior of the handle housing. This keep control of the bending radii and that bending radii are not determined by the cover of the operating handle, but by a predetermined configuration inside the operating handle.

In a further practical embodiment the handle housing comprises an interior chassis carrying the first operating member, and the chassis is provided with stop members limiting movement of the first operating member.

Turning first toFIG. 2an assembled endoscope1according to the present invention is shown. The endoscope1has a proximal end with an operating handle2to be held in one hand by an operator. Accordingly, the operating handle is shaped in a manner ergonomically suitable for operator, in particular but not exclusively for the hand of the operator, as arms and joints may also play a role in the ergonomics. From the handle2an insertion tube3extends towards the distal end of the endoscope. At the distal end of the endoscope1the insertion tube3ends in a bending section4and a tip part5. The bending section4is in mechanical connection with a first operating member6, digitally operable by the operator, e.g. by the thumb, thereby allowing the operator to bend the tip part5in a desired direction when advancing the insertion tube3towards a desired location, e.g. through a body cavity of a patient. In addition to the first operating member6the endoscope1comprises a tool operating member22adapted to operate a tool55at the tip part5of the endoscope1. The tool operating member22is preferably in the form of a trigger or push-button so accommodated in the housing that it may be operated by the same hand as used for operating first operating member6. In the configuration shown the first operating member6is adapted to be operated by the thumb of the operator whereas the push-button is adapted to be depressed independently thereof by the index finger of the very same hand of the operator. This allows singled handed use of the endoscope. As can be seen the push-button is has been partially depressed allowing the tool55to be advanced forwardly from the distal end of the tip5of the endoscope1. This partially depressed position which will be described in greater detail later is an intermediate position between the fully released position shown inFIG. 4a, towards which the push-button is preferably spring biased, and the fully depressed position shown inFIG. 4b, which will also be described later.

As can also be seen inFIG. 2, the endoscope1comprises a flexible connection cable7with a connector8allowing the endoscope1to be connected to a monitoring device such as a monitor92shown inFIG. 3forming part of an endoscope1and monitor92system.

Turning now toFIGS. 1, 1aand1ban exploded view of the endoscope1is shown. As mentioned, the endoscope1has an operating handle2at the proximal end thereof i.e. at the left-hand side ofFIG. 1a. The operating handle2is assembled from and comprises a number of handle parts to be described later. From the operating handle1, the insertion tube3comprising a number of insertion tube parts to be described later extends towards the distal end of the endoscope, i.e. towards the right-hand side ofFIG. 1b. The first operating member is is connected to a control lever37which is mounted in the handle1by means of trunnions26positioned in pivotal bearing38(cf.FIG. 8). The control lever37allows maneuvering of the bending section4via a Bowden cable arrangement27comprising pull-wires31and outer guide tubes60. The control lever37is attached to the first operating member6, and at least the first operating member6extends to the outside of the endoscope handle2through a slit in the shell part10to be accessible by a thumb of the an operator. As can be seen inFIG. 1athe control lever37may be provided with a protruding tap35for limiting movement of the control lever37and thereby the bending radius of the bending section4. This is achieved by providing the interior of the operating handle2with one or more stop members36a,36bthat limit movement of the control lever37by only allowing movement of the tap35between the two stop members.

The operating handle2comprises at least two shell parts9,10forming the outer housing walls of the handle housing of the operating handle2. The two shell parts9,10form the outer housing walls and are shaped to provide an ergonomically suitable operating handle for an operator, gripping it with one hand. In addition to the two shell parts9,10a transition part11forming the transition from the operating handle to the insertion tube3, may be provided. This transition part may also form part of the handle housing. However, the two shell parts9,10constitute the major part of the housing in the embodiment shown. The shell parts9,10and almost all other parts are mounted on a chassis12.

Turning now toFIG. 5details of the distal end of the insertion tube3with the articulated bending section4is shown. Some parts, such as an external sheath80normally covering the bending section4, have been removed for clarity. The bending section comprises a number of segments61,62,65,66. More specifically a distal end segment61, a proximal end segment65(not fully visible inFIG. 5), a plurality of articulated bending segments62and an intermediate segment66. In the illustrated embodiment, the number of bending segments62are is six, but the skilled person will understand that the precise number is less important. The distal end segment61is tubular shaped with an interior end wall towards the intermediate segment66. The interior end wall is provided with through holes for fastening the pull wires31. I.e. distal end segment61has a generally circular cross section with one passage from the end wall to the most distal part. The end wall is adapted with openings to allow passage of electrical supply wires and pull-wires. The tubular shape allows the distal end segment61to least partially accommodate a camera module64comprising a camera, light emitting diodes and electronic circuits as well as it accommodated a portion of a tube72forming a part of a working channel. The working channel extends inside the insertion tube3all the way from the distal tip part5to the operating handle13and is formed by tube72and tube73, which are connected by a connecting tube member74. The working channel may via a suction port76on the handle be connected to a standard external suction, e.g. wall suction present in hospital environment by means of an attached tube.

One embodiment of the bending section4is shown inFIG. 6without any attached parts. It can be seen that there is one distal end segment61, one proximal end segment65, an intermediate segment66and six articulated bending segments62. The bending segments62are interconnected by means of flexible hinge members63formed by cut-outs25between the hinge sections62. As can be seen fromFIGS. 5 and 6the intermediate segment66is longer than the bending segments62. Preferably, the intermediate segment66is also longer that the distal end segment61. Hence in the embodiment ofFIGS. 5 and 6the intermediate segment66has a length l1, which is longer than a length l3of the distal end segment61and a length l2of a bending segment62, where the distal end segment61has a length l3, which is longer that a length l2of a bending segment. In a preferred embodiment the length l1of the intermediate segment is about 1.5-3 times the length l3of the distal end segment and is 4-5 times the length l2of a bending segment.

The bending segments62generally have the same cross-section, which generally correspond to the end view ofFIG. 7. That is to say a generally circular cross-section with four passages67,68,69. The first passage67is circular and adapted to engage and support the outer wall of the tube72forming a portion of the working channel. This first passage is relatively large, and the centre70of the cross-section of the bending segments actually lies within the first passage67. The second passage68is adapted to accommodate electrical supply wires for the camera module64. The camera and the light emitting diodes are mounted on a small circuit board to which the supply and signal wires are connected. The last two passages are pull wire passages69for guiding pull wires31of a Bowden cable arrangement27, where the pull wires are guided in outer guide tubes60. The pull wire passages69are arranged symmetrically opposite each other on either side of the plane in which the hinge members63extend. Preferably, the intermediate segment66have the same cross-section as shown inFIG. 7, i.e. the same as the bending segments62.

The ends of the pull-wires are secured in the distal end segment as well as connected to the control lever6in the operating handle2. Thus by manipulating the control lever6the pull wire may be tensioned on one side of the plane of the hinge members63and slacked on the other, thus allowing the articulated bending section4to bend in a desired direction. The distal end segment preferably also has a number of cut-outs, preferably through holes. These help securing the camera module and the end of the tube9etc. when these are moulded-in by means of plastic material, e.g. in a process similar to the one described in WO-A-2010/066790 incorporated herein by reference. As seen inFIGS. 5 and 6the bending section4is provided with a recess25between the distal end segment61and the intermediate segment66. This most distal recess25is provided to facilitate assembly and fastening of the pull-wires to the distal end segment61in a preferred embodiment, wherein the tip part5is moulded as described above and where distal recess25is at least partly filled with moulding material for mounding the tip part5so that the distal end segment61and the intermediate segment66are fixed to each other in a non-articulated manner. Evidently, the pull-wires may be fastened to the proximal portion of the intermediate segment66. Alternatively, the pull-wires may be affixed to via through holes at a proximal part of the intermediate segment where an outer surface of the intermediate segment is provided with apertures for allowing guidance of the pull-wires to and from the through holes during assembly of the pull-wires.

As best seen inFIG. 8, the chassis12preferably shell shaped, i.e. the chassis12comprises an essentially shell shaped structure with a shell wall having an inner surface16and an outer surface17linked by an edge18, said essentially shell shaped structure defining an interior compartment19delimited by said inner surface16and the edge18of the shell wall, the edge thus defining main opening20of said interior compartment19. It will be understood that the chassis12can be designed mainly based on technical requirements, in such as kinematic chains of movable parts to be described further below, and thus be optimized for those technical requirements without having to inherit constraints from the ergonomic requirements of the handle2, i.e. the shape of the two shell parts9,10.

As mentioned above, the chassis12is adapted to for the mounting of almost all parts of the endoscope1. In particular, the chassis12is adapted for holding movable parts forming of kinematic chain from the push-button forming the tool operating member to the motion transfer means transferring the movement of the tool operating member22to the tool55.

One such adaptation is a pair apertures41in the form of essentially cylindrical through holes can be seen inFIG. 1a. The apertures41serve as bearings of trunnions42carrying rotary member such as a pinion44, best visible inFIG. 12. As can be seen fromFIGS. 15 to 17, the pinion44is adapted to be in engagement with a curved rack45. The curved rack45is shown separately inFIG. 13. The curved rack45has a first free end46and a second end with trunnions47held loosely in suitable receptacles inside the push button forming the tool operating member22. The rack45as such is loosely held in a guideway comprising a first side85, a second side86and a curved bottom87adapted to keep the rack45in engagement with the pinion44. The first side85and the second side86as well as the curved bottom87are preferably formed integrally with the remainder of the chassis12, e.g. in an injection moulding process. The first side is preferably constituted by a plane surface of a thickened part of the wall, i.e. a raised part of the inner surface16of the chassis12.

Rotation of the pinion44may be effected by an operator moving the push-button forming the tool operating member22, e.g. depressing it using an index finger, upon which the push-button forming the tool operating member22transfer motion to the curved rack45, in turn rotating the pinion44.

On the pinion44, two levers48and49are provided. These levers48and49are in rigid connection with the pinion44. The levers48and49have different lengths so as to influence a first motion transfer member53and a second transfer member54of the motion transfer means in different ways in order to effect a compound movement of the tool55. As will be described later this compound movement comprises both a linear movement of the tool55and a task movement of the tool55.

As can best be seen inFIG. 1a, the first motion transfer member53is arranged co-axially within the second motion transfer member54. The first motion transfer member53and the second motion transfer member54, in turn, are arranged within in tubular members71,72,73,74, which form part of the working channel of the endoscope, together with an e.g. T- or Y-shaped bifurcated section75providing the entry port to the working channel.

As can best be seen fromFIGS. 18a-18cthe first and second motion transfer members53,54each comprise different sectors with different rigidities or bending properties, matching the requirements of the insertion tube3, and the working channel, which both also has different bending properties along the length thereof. The first motion transfer member53preferably comprises a rigid rod piece at the proximal end and a rod or tubular piece at the tool55. Between the two, the first motion transfer means may comprise a flexible wire.

The first motion transfer member53is terminated in an end sealing means51. Apart from sealing the proximal end of the working channel, the end sealing means also serves as part a first kinematic chain by being pivotally connected to the first lever48.

The first kinematic chain is as follows: Depressing the tool operating member22will move the rack45in a curvilinear movement via the trunnions47. The rack45, which has teeth in permanent engagement with the pinion44, will rotate the pinion44and the first lever48rigidly connected thereto. The rotating first lever will consequently push the proximal end of the first motion transfer member53, causing the tool55arranged at distal end of the first motion transfer member31to be moved out of the working channel beyond the distal end of the insertion tube3of the endoscope1. Being spring biased, by e.g. a pair coil springs83accommodated in the chassis12, a release of the tool operating member22will automatically return the tool operating member22to the position ofFIG. 4a.

The second motion transfer member54forms a sheath for the first motion transfer member and preferably comprises a coil spring part54awound from wire with a rectangular cross section towards the proximal end, and a coil spring part54bwound from wire with a circular or round cross section towards the distal end. Preferably, the outer motion transfer member comprises at least two sections54a,54bdiffering from each other in rigidity and with a second connecting transition56connecting the two sections54a,54b. At the distal end, the secand motion transfer member is terminated in a rigid tubular member95.

The second motion transfer member54is terminated in a first tubular end member52. The rigid part of the first motion transfer member53passes coaxially trough the first tubular end member52and into the remainder of the second motion transfer member54. The passage through the first tubular end member52as well as through the remainder of the second motion transfer member54is adapted to allow mutual lengthwise relative motion, i.e. mutually reciprocating movement.

Not unlike the sealing end member51, the first tubular end member52serves as part of a second kinematic chain adapted to provide a different motion pattern of the second motion transfer member54as compared to the first motion transfer member53in response to the very same depression, i.e. one and the same as the one described above. This is achieved by the second lever49which is also rigidly attached to the pinion44but has a different length than the first lever48. At the end of the second lever49a first arm50is provided in articulated connection with said second lever49. The second end of the first arm50is in articulated connection with a clamping means79adapted to clamp the tubular end means52with a part71of the working channel wall interposed. The interposed part71is preferably a flexible hose part. Preferably, the flexible hose part is made from the very same tubular material as is used to form the outer sheath80of the insertion tube3at the distal end around the bending portion5. To ensure good grip between the interposed part of the working channel wall71and the first tubular end member52the first tubular end member may comprise concentric ribs98or corrugations, or similar means. The articulations of the first arm50are preferably provided as integrally moulded foil hinges93, as best seen inFIG. 15.

Accordingly, the second kinematic chain is as follows: Depressing the tool operating member22will move the rack45in a curvilinear movement via the tool trunnions47. The rack45, which has teeth in permanent engagement with the pinion44, will rotate the pinion44and the second lever49rigidly connected thereto, so as to change their relative position while remaining in the engagement. The rotating second lever49will consequently push the proximal end of the first arm50, thereby moving clamping means79at distal end of the first arm50, articulating the first arm50as necessary in the foil hinges93. The clamping means79moves the clamped part of the working channel wall part71. Being clamped, the clamped part of the working channel wall71moves the first tubular end member of the second motion transfer member54towards the distal end of the working channel, consequently causing the distal end of the second motion transfer member54to be moved out of the working channel beyond the distal end of the insertion tube3of the endoscope1. The distal end of the second motion transfer member54is preferably terminated in a second tubular end member95. Being spring biased, by e.g. a pair coil springs83accommodated in the chassis12, a release of the tool operating member22will automatically return the tool operating member22to the position ofFIG. 4a.

Providing these two different kinematic chains allows the tool55to perform a compound movement comprising both a linear movement and a task movement, during one continuous depression of the tool operating member22. In the linear movement, the tool55is advanced to a position in front of the distal end of the insertion tube3of endoscope1where it is visible from the camera built into the tip part4of the endoscope1, and hence visible by the operator on the monitor92attached to the endoscope via cable7and connector. This may be performed by only partially depressing the tool operating member22, e.g. to the position shown inFIG. 2, where with a suitable layout of the first kinematic chain will not advance any further but remain stationary or at least almost stationary with respect to the distal end of the insertion tube3of the endoscope even if the tool operating member is depressed further. Having located the correct position for operating the tool55, e.g. by laterally moving the tip4of the bending section5at the distal end of the insertion tube3of the endoscope1using the first operating member6simultaneously with the tool operating member, the task movement can be performed.

In the preferred embodiment the tool55at the distal end of the first motion transfer member53comprises a self expanding configuration, such as a pair of spring tweezers, forceps, a spring loop, or the like which as long as it is accommodated in the tubular member95is compressed, as shown inFIG. 18b. Accordingly, it will auto-expand if it is advanced out the second tubular member95, to the configuration shown inFIG. 2. Now, due to the second kinematic chain operating independently of the first kinematic chain, the second motion transfer member is held stationary is in the working channel during the first part of the depression of the tool operating means22to the intermediate position. Then, still due to the independent operation of the first and second kinematic chains, continuing the continuous movement by further depressing of the tool operating member22will cause the second motion transfer member to also start moving thereby advancing the second tubular end member95. Consequently, the second tubular end member95slides over the tool55again, because as mentioned above the first kinematic chain is laid out to keep the tool55stationary in the field of vision of the camera at a distance from the tip part4of the insertion tube3of the endoscope1. This will the effect the task movement of closing the tool55because the configuration as show inFIG. 18bis now restored, but this time at the position at the location outside the working channel set at the intermediate depression of the tool operating member22. Keeping this position is of outmost benefit for the operator, who having only one camera eye does not perspective vision and therefore as difficulties in judging distances. Thus, having found the position where a stent a other object is to be gripped, e.g. by touching them with the tool, the operator can do so without further advancing or retracting of the entire endoscope1.

Having gripped object, such as a stent, with the tool55in this way the object may then be removed from the body by retracting the entire endoscope1from the cavity whilst holding the tool operating member22depressed.

For the sake of clarity it should be noted that the term continuous movement is merely to be understood as a movement of the tool operating member from released state to a depressed state. It does not imply that the movement cannot be paused by the operator during the continuous movement. It does also not imply that the movement cannot be partially reversed by the operator releasing the tool operating member22, in the search for the gripping location. In fact a latch means may be included to partially intermit the procedure without the tool changing its position. This could be a simple click mechanism as is well known in the art, latching when the tool operating member22is depressed fully, and releasing upon repeated depression og the tool operating member22. As mentioned above, and as can be seen fromFIGS. 13 and 15-17the rack45has a curvature. This curvature preferably matches the curvature of the curved bottom87of the guideway, so that the teeth of the rack45are kept in engagement with the matching teeth of the pinion44. This curvature saves space helping to fit the rack45and pinion44mechanism within the chassis12and the handle housing2. The skilled person will understand that the forces and torques of the kinematic chain may be also be influenced by suitable choice of curvature and length of the rack45and diameter of the pinion44provided it is generally circular. The pinion44with a generally oval shape or other curvature is also envisaged. The skilled person will also understand that the two kinematic chains, and in particular their mutual differences could be influenced by suitable choice of the length of the levers48and49, their angular spacing on the pinion44, and the length and articulations of the arm50, as well as by the provision of further arms. This may allow specific adaptation of the kinematic chains to the specific requirements of different tools55.

As will be understood from the above the first and second motion transfer members are located within the working channel of the endoscope1, comprising tubular members71,72,73,74forming a generally tubular working channel wall and an e.g. T- or Y-shaped bifurcated section75providing the entry port to the working channel.

Starting from the distal end of the endoscope1, a first tubular member72adapted to comply with the bending requirements of the bending section5of the endoscope1is provided. The first tubular member72passes through the bending section and thus provides an exit port96of the working channel at the tip4thereof. Via a short joint tube74, a second tubular member73is joined at one end with the first tubular member72and provides a longer intermediate section of the working channel. Hence the working channel is formed by a tube that comprises at least a first proximal section73and a second distal section72with a first connecting transition74connecting the two sections.

From the perspective view inFIG. 1bit is realized that it is preferred that the connecting transition member74of the working channel and the connecting transition member56of the second motion transfer member54are staggered with respect to each other along the length of the insertion tube3. Hence when the second motion transfer member54is moved back and forth along the inside of the working channel the two transitions are staggered along the length of the insertion tube in all conditions of use.

The second tubular member73is generally more rigid than the first tubular member72. The second tubular member73is however still quite flexible. More specifically, the second tubular member73and a second outer tube section81surrounding it are so flexible that they allow a loose knot to be tied on the insertion tube3. The alternative is a rigid or semi-rigid endoscope where the insertion portion is rigid, only slightly bendable or hinged, and which does not allow a knot to be tied on the insertion tube. It is preferred to make the first tubular member71of a first polyurethane elastomer and to make the first tubular member72of another polyurethane elastomer. Both polyturethane elastomers could be Pellethane®, which is available in different variants. The second tube member73may also comprise polyurethane. At the other end of the second tubular member73, the second tubular member73is joined to a first branch of a preferably T-shaped bifurcated section75. The bifurcated section has s second branch which provides the entry port to the working channel together with a connector76or lead-in mounted on the chassis12. In the preferred embodiment shown the bifurcated section is75T-shaped. That is to say perpendicular that the second branch is perpendicular to the first branch. Evidently the second branch could also be arranged a different angle, so as to provide more of a Y-shape. The connector76allows a suction means to be attached for extracting fluid from a body cavity via the working channel. Alternatively a fluid source may be attached to the connector76, allowing e.g. irrigation or aspiration of the body cavity via the working channel. The third branch of the bifurcated section75is preferably aligned with the first branch so as to provide an unobstructed straight passage through the bifurcated section75for the first and second motion transfer members53,54. To the third branch of the bifurcated section a first end of a third tubular member is attached, which at least in the released position of the operating member22is aligned with the first and third branch of the bifurcated section75and the second tubular member73, when the latter is in a relaxed position, i.e. not influenced by external forces from body cavity walls or the like. The second end of the third tubular member71forms the proximal end of the working channel, and is terminated in an end sealing means51. As described above end sealing means, not only seals the proximal end of the working channel, but also serves as part a first kinematic chain by being pivotally connected to the first lever48. The third tubular member71is preferably in the form of a hose of a highly flexible material, as compared to the remainder of the tubular members forming the working channel. The hose could be provided with corrugations or the like to from a bellows. Making the third tubular member of a highly flexible material serves two purposes.

The first purpose is that it allows the length of the working channel to adapt to the movement of the members of the first kinematic chain in particular the first lever48, the first motion transfer member53and the interposed end sealing member51. The flexible material allows the working channel to deform in order to adapt in length to accommodate the movement of the first motion transfer member. However, by being flexible the material also allows working channel to deform in order to comply with the swinging movement of the end sealing member caused by the first lever48moving the end sealing member51out of alignment with the first and third branches of the bifurcated member75and second tubular member73. By being able to comply with these movements, the third tubular member71allows transfer of movement using parts of the working cannel itself, in turn, allowing transfer of movement from the operating means22to the tool55without breaching the integrity of working channel wall. Undesired ingress of pollutants is thus avoided.

The second purpose is similar to the first purpose, because by being flexible the material also allows working channel to deform in order to comply with the movement of the members of the second kinematic chain, in particular the movement of the first tubular end member52caused by the second lever49in conjunction with the arm first50. As mentioned above this movement is transferred via the working channel wall, because the third tubular member72is clamped between the first tubular end member52and clamping member79. By being able to comply with these movements, the third tubular member71allows transfer of movement using parts of the working cannel itself, in turn, allowing transfer of movement from the operating means22to the tool55without breaching the integrity of working channel wall. Undesired ingress of pollutants is thus avoided.

Clamping the third tubular member72in this way between the clamping member79and first tubular end member52, provide minor problems which the present invention also overcomes. One problem is to ensure good grip so that the relative position between the clamping member79and the first tubular end member52does not change due to the forces in the kinematic chain when the tool55is operated. The first tubular end member52the first tubular end member may comprise concentric ribs98or corrugations, or similar means. A second problem is with this configuration of the working channel with a sealed appendix at the proximal end, the output port at the distal end, and entry port located between them, it becomes difficult to sterilize the interior of the appendix, in particular the proximal end thereof between the end sealing means51and the first tubular end member52, because the access of sterilizing fluid, such as Ethylene Oxide, may be blocked by the first tubular end member52. Sterilisation with Ethylene Oxide (ETO sterilization) is preferred for sterilisation, because the endoscope1according to the invention is preferably a disposable endoscope made from low cost materials, which may not necessarily withstand other sterilization processes such as the high temperature and pressure of an autoclave sterilisation.

Accordingly, as can be seen inFIG. 15aan elongate groove along the first tubular end member52and across the concentric ribs98is provided. In assembly this groove is made to register with gap in the clamping means79, so as to allow an open fluid passage along the first tubular end member52. Preferably, the inner diameter of the third tubular member71is selected to be larger than the largest outer diameter of the first tubular end member52so as to form a pouch in the first tubular member71also registering with the groove99.

A third problem is that using the working channel wall as a part of the kinematic chains, and therefore in the second kinematic chain gripping and the third tubular member71somewhere between the sealing end member51and the bifurcated section75, may cause inadvertent overstretching of the flexible material of the third tubular member, leading, in turn, to an undesired rupture of the working channel wall. To overcome this, a strike plate59is provided in the chassis12. When the clamping member79is moved under the by depression of the operating member22by the operator, the clamping member will strike the underside (as understood with reference toFIG. 1) of the strike plate59, and will be limited in further motion. Thus even if the operator presses inappropriately hard on the operating member22, the clamping means will not tear the third tubular member71and breach the integrity of the working channel wall. Preferably, the strike plate serves the dual purpose of also accommodating electronics of the endoscope1such as a printed circuit board62.

The present invention thus provides an endoscope with a working channel, used not only for accommodating parts of the control mechanism of a tool but also forming itself a part of the control mechanism. The skilled person will understand that the arrangements described above, and in particular the kinematic chains are only exemplary embodiments, and that the endoscope according to the present invention may be devised in many different variants without departing from the scope of the invention as expressed in the claims.