Patent Publication Number: US-11642014-B2

Title: Handle for an endoscope

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a National stage application filed under 35 U.S.C. § 371 of International Application No. PCT/EP2018/055603, filed on Mar. 7, 2018, which claims the benefit of Denmark Patent Application No. PA 2017 70167, filed on Mar. 8, 2017, which applications are incorporated herein by reference thereto. 
     TECHNICAL FIELD 
     The present invention relates to endoscopes in general and more specifically to means for maintaining a tensioned pull wire in an endoscope. 
     BACKGROUND OF THE DISCLOSURE 
     Endoscopes are well known devices for visually inspecting inaccessible places such as human body cavities. Typically, the endoscope comprises an elongated insertion tube with a handle at the proximal end as seen from the operator and visual inspections means, such as a built in camera, at the distal end of the elongated insertion tube. This convention of distal and proximal, proximal being the end closest to the operator and distal being the end remote from the operator, as used above for the endoscope in general will, where applicable, be adhered to for all parts throughout this description. Electrical wiring for the camera and other electronics such as LED lighting run along the inside of the elongated insertion tube from the handle to the tip at the distal end. Instead of using cameras, endoscopes may also be fibre-optic, in which case the optical fibres run along inside of the elongated insertion tube. Also, a working channel may run along the inside of the insertion tube from the handle to the tip, e.g. allowing liquid to be removed from the body cavity or allowing the insertion of surgical instruments or the like into the body cavity. 
     Furthermore, in order to be able to maneuver the endoscope inside the body cavity, the distal end of the endoscope may comprise a section with increased flexibility, e.g. an articulated tip part allowing the operator to bend this section. Typically, this is done by tensioning or slacking pull-wires in a guide tube also running along the inside of the elongated insertion tube from the articulated tip part to a control mechanism with a control knob in the handle in an arrangement commonly known as a Bowden cable. 
     The pull-wire running along the inside of the guide tube of a Bowden cable normally extends with a predetermined length over either end allowing an operating member to be attached to a free end, in the following referred to as the proximal end, and an operated member to be attached to the other free end, in the following referred to as the distal end. When the ends of the guide tube are held stationary, movement of the proximal end of the pull-wire with respect to the guide tube is transmitted to the distal end as a corresponding movement of the distal end of the pull-wire with respect to the guide tube, so as to effect a movement of the operated member. 
     One way of securing the proximal ends of the guide tubes is disclosed in WO2014/127780. Here, the proximal ends of the guide tubes are terminated in a termination block located in a seat or recess provided on the inside of the handle housing wall of the handle of the endoscope. More specifically, the proximal ends of the guide tubes are terminated in suitable bores in the termination block. More specifically the bores are stepped in order to provide a ledge which the end of a respective guide tube abuts, whereas the pull wire continues through the bore towards the operating member. 
     Another way of securing the proximal ends of the guide tubes is disclosed in WO2010/066789. Here the proximal ends of the guide tubes terminate at a pillar protruding from the inside of the handle housing wall into the interior of the handle. It is stated that the termination directs the cables towards their attachment points at the operating member, but no details of the termination and of how this is achieved are disclosed. 
     Furthermore, U.S. Pat. No. 3,897,775 describes a multiple use endoscope having an anchoring block in which two pairs of pipes are secured in four bores in a manner not disclosed or otherwise indicated. 
     SUMMARY OF THE DISCLOSURE 
     Based on this prior art it is the object of the present invention to provide an improved way of securing the end of a guide tube in a given position with respect to the operating member of an endoscope, in particular with respect to the handle housing in which the operating member is accommodated. 
     According to a first aspect of the present invention this object is achieved by a handle for an endoscope, said handle comprising, a handle housing, an operating member accommodated in said handle, at least one guide tube adapted for surrounding and supporting at least one pull wire over a first part of the length of the pull wire, an anchoring block for securing at least one part of the guide tube in a predetermined position with respect to the operating member, said anchoring block comprising at least one bore adapted for insertion of said at least one guide tube, wherein said anchoring block comprises at least one inlet passage in fluid communication with said at least one bore. 
     According to a second aspect of the present invention this object is achieved by an endoscope having a handle comprising, a handle housing, an operating member accommodated in said handle, at least one guide tube adapted for surrounding and supporting at least one pull wire over a first part of the length of the pull wire, an anchoring block for securing at least one part of the guide tube in a predetermined position with respect to the operating member, said anchoring block comprising at least one bore adapted for insertion of said at least one guide tube, wherein said anchoring block comprises at least one inlet passage in fluid communication with said at least one bore. 
     By providing such an anchoring block it becomes very easy during manufacture to position the free end of the guide tube with respect to the handle and, in turn, the operating member to which the pull wire is attached. At the same time it becomes very easy to secure the free end of the guide tube in this position by pouring a correct amount of a suitable glue or adhesive into the anchoring block. Furthermore, the use of glued parts in this way renders the entire construction of the endoscope more suitable for single use because parts that in a reusable endoscope would have to be mounted in a detachable manner for replacement may simply be secured by gluing. Thus, complicated constructions for allowing the detachment and replacement are avoided. 
     According to a first embodiment of the present invention, the at least one bore is a through bore allowing the through passage of the guide tube. This allows the free end of the guide tube to visibly protrude from the anchoring block towards the operating member, in turn allowing verification of the proper insertion of the guide tube into the anchoring block. 
     According to another embodiment of the present invention, the anchoring block comprises a transparent or translucent plastic material. This allows for the use of a glue or a resin which will cure or set under irradiation with light, in particular ultra violet light. In a further specific embodiment the anchoring block is made from one material which is transparent or translucent. 
     According to a further embodiment, the handle housing comprises a receptacle adapted for accommodating the anchoring block. This allows the provision of the anchoring block as a separately manufactured item, in turn, facilitating both the manufacture thereof and the handle housing, as compared to the manufacture of the anchoring block as an integral part of the handle housing. 
     According to a preferred embodiment, the anchoring block is adapted for insertion into the receptacle in the handle housing. Adapting it for insertion, allows the easy placement of the anchoring block in the receptacle. 
     According to a further preferred embodiment, the receptacle is formed integrally with the handle housing. This allows good control of the position of the anchoring block with respect to the operating member when correctly inserted into the receptacle. 
     According to an especially preferred embodiment, the anchoring block comprises an essentially cylindrical protrusion. This, cylindrical protrusion is advantageous when during assembly of the endoscope correct tension has to be applied to the pull wire. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will now be explained in greater detail based on non-limiting exemplary embodiments, and with reference to the drawings on which: 
         FIG.  1    shows a perspective view of an endoscope with a handle according to the present invention, 
         FIG.  2    shows a perspective view of a handle of an endoscope in accordance with the present invention, 
         FIG.  3    shows a cross-sectional view of the handle of  FIG.  2    taken along the line III-III, 
         FIG.  4    shows a perspective view of the handle of  FIG.  2    with a handle housing part removed for a better view of the internal parts, 
         FIG.  5    shows another perspective view of the handle of  FIG.  2    with the handle housing removed as in  FIG.  3    for another view to the internal parts, 
         FIG.  6    shows a perspective view of the anchoring block with the Bowden cables and the operating member to which they are attached, 
         FIG.  7    shows a partially exploded view of details of the bearings of the operating member, and 
         FIG.  8    shows details of the mounting of the operating members and the bearings in the handle housing. 
     
    
    
     DETAILED DESCRIPTION 
     Turning first to  FIG.  2    a perspective view of a handle  1  of an endoscope according to the invention is shown. From the handle an insertion tube  2  extends. The insertion tube  2  is shown only in part in  FIG.  2    as the details thereof are not of importance for the present invention, and as such well known in the art. A general overview is seen in  FIG.  1   . Details of the insertion tube may e.g. be found in the aforementioned WO2014/127780 incorporated herein by reference. The handle  1  comprises a handle housing with lid part  3  and a main body part  4  and a number of minor housing parts. The lid part  3  comprises an elongate aperture  5  through which a control knob  6  of an operating member  7  protrudes at an angle to the lid, so as to allow it to be readily manipulated by a thumb of an operator. The operating member  7  is not itself visible in  FIG.  2   , but the shield  35  thereof is visible through the aperture  5 . The main body part  4  is adapted to accommodate most of the internal parts of the endoscope handle, fixed as well as movable, such as the aforementioned operating member  7 . When closed by the lid part  3  the main body part  4  and the lid part  3  form a generally tubular handle housing. The handle housing is further closed at the proximal end of the endoscope by an end piece  8 . At the opposite end, the tubular handle housing is closed by a transition part  9  providing the transition from the handle  1  to the insertion tube  2 . The end piece  8  is preferably provided with and access port  10  for an internal working channel  14  (not visible in  FIG.  2   ) leading to the distal tip  34  (shown only in  FIG.  1   ) of the endoscope in a well-known manner. The main body part  4  also preferably accommodates a lead-in  11  for connecting a vacuum suction hose to an internal suction channel  13  (also not visible in  FIG.  2   ) in the endoscope, in a likewise well-known manner, as well as a push-button  12  controlling a valve for activation of the suction from the distal end of the insertion tube  2  though the suction channel  13  of the endoscope. 
     Turning now to the cross-section in  FIG.  3    some of the internal parts accommodated in and held by the main body part  4  of the handle housing can be seen. These parts include inter alia the already mentioned operating member  7  and the working channel  14 , but also an anchoring block  15  for the guide tubes  16  of pull wires  17  of the Bowden cables leading from the operating member  7  to an articulated distal tip part  36  (shown only in  FIG.  1   ) of the endoscope at the distal end of the insertion tube. The details of the articulated distal tip part  36  are well-known in the art and not as such of interest in the present invention, and will therefore not be described in detail. An example is found in the aforementioned WO2014/127780. In the preferred embodiment there are two pull wires  17 , but the skilled person will know that there may be only one, but also more than two, e.g. three or four. 
     In the preferred embodiment shown, the anchoring block  15  is a separate element held in a fixed position with respect to the handle housing, by a receptacle  18  into which it is inserted. The receptacle  18  is preferably formed integrally with the main body part  4 , more specifically as one or more protrusions on the inside wall thereof. The anchoring block  15  may be secured in the receptacle by means of adhesive or the like, or it may simply be clamped by one or more suitably engaging protrusions or the like, provided on the inside wall of the lid part  3 , when the latter is in position. As can be seen from  FIG.  3   , in the illustrated preferred embodiment only a single engaging protrusion is provided in the form of a cross-rib  19  extending perpendicular from the inside wall of the lid part  3 . To further ensure the position of the anchoring block  15  in the receptacle  18 , the anchoring block  15  may comprise guide means in the form of grooves  25  (see  FIG.  6   ) adapted to engage corresponding ribs provided on the inside wall of the main body part  4 . The anchoring block  15  in a preferred embodiment comprises a main body member, generally in the shape of a rectangular or square, i.e. a tile or a slab with two opposite large sides and four smaller sides connecting the large sides. Generally, the pairs of opposite sides are parallel to each other, but to ensure the correct position it is preferred that one side  26  is adapted to engage inside wall of the main body part, and therefore has a matching curvature and angle. The angle provides a wedge which not only facilitates the insertion into the receptacle, but also indicates to the assembling person, the correct orientation of the anchoring block when it is inserted into the receptacle. 
     The anchoring block  15  comprises at least a number of bores  20  corresponding to the number of Bowden cables used in the specific endoscope, i.e. two in the present embodiment. The bores  20  are through bores and generally have an internal diameter allowing the guide tubes  16  to pass all the way through so that the proximal end of the guide tubes  16  protrude visibly from the anchoring block  15 . It would of course also be possibly to have through bores with varying diameter, in particular stepped, so as to allow the guide tubes  16  to abut a ledge in the bore  20  inside of the anchoring block  15 , so that only the pull wires pass all the way through the anchoring block  15 . This offers the advantage of securing the guide tubes  16  even better to the anchoring block  15 . This, however, is considered less desirable because it entails the risk of introducing unnecessary friction from the anchoring block  15 , which, unlike the guide tubes  16 , is not necessarily optimized for low friction. 
     As can be seen in  FIGS.  3 - 7   , the diameter of the bore  20  generally exceeds the outer diameter of the guide tube  16 . This allows plenty of room for an adhesive in the form of glue such as a curable resin to enter and secure the guide tube  16  with respect to the anchoring block  15 . 
     Turning now to  FIG.  2 - 7   , the main body part  4  with the anchoring block  15  is shown at another angle. From this angle it can be seen that in the anchoring block  15  a cut-out  21   a  is formed. The cut-out  21   a  leads to the bore  20  and thus provides an inlet passage  21  in fluid communication with the bore  20 . The inlet passage  21  is located more or less in the middle of the length of the bore  20 . This allows the adhesive for securing the guide tube  16  to be simply poured into the bore  20 , distribute itself around the guide tube  16  and in either direction towards the openings  20   a ,  20   b , in distal and proximal surfaces  15   a ,  15   b  of the anchoring block  15  (i.e. for each bore  20 , a first opening  20   a  in the distal surface  15   a  and a second opening  15   b  in the proximal surface  15   b ), at the respective ends of the bore  20 . When the adhesive sets, the guide tube  16  is secured with respect to the anchoring block  15 . Because the anchoring block  15  is inserted and held in the receptacle formed on the inside wall of the main body  4  the guide tube  16  is fixed with in a predetermined, desired position with respect to the handle housing and, in turn, with respect to the operating member  7 . The adhesive is preferably an UV curable resin, curing under the irradiation with ultra violet light (UV). Accordingly, the anchoring block is preferably made of a transparent or translucent material, in particular a transparent or translucent plastic material. 
     As can be seen from  FIGS.  5  and  6    the orientation of the bore  20  in the anchoring block is carefully selected to point the guide tube  16  towards an attachment point  37  at the operating member  7 , when the anchoring block  15  is correctly inserted in the receptacle  18 . 
     With the guide tube  16  properly secured in the correct orientation in the anchoring block  15  the guide tube  16  may be cut at a suitable point and the remainder removed so as to leave the pull wire  17  inside uncovered. The point where the guide tube  16  is cut now provides the free proximal end of the guide tube  16 . A small part of the guide tube is protruding from the anchoring block  15 , i.e. between the anchoring block  15  and the proximal end of the guide tube  16 . Accordingly, an uncovered length of the pull wire  17  now extends from the proximal end of the guide tube  16 . Since the proximal end of the guide tube  16  points towards the attachment point  37  the pull wire may be drawn to the attachment point  37  in a generally straight line forming a tangent to the outer cylindrical surface  23  of the operating member  7 , and in particular without any kinks or discontinuities at the proximal end of the guide tube  16 . Such kinks or discontinuities could increase wear on the guide tube  16 , the pull wires  17  or even the anchoring block  15 , but are thus avoided. Moreover, because the short length of guide tube  16  extends from the anchoring block in the right direction it is of less importance where exactly the guide tube is cut, thus facilitating and speeding the manual assembly process of the handle. Because precision it not so important, it may instead be advantageous to cut the guide tube  16  to length before it is secured, or even inserted, in the anchoring block  15 . 
     At the attachment point  37  the pull wire  17  is attached to the operating member  7 . From the attachment point  37  there is a transition surface onto an outer cylindrical surface  23 . The cylindrical surface ensures that when the operating member is turned, the pulling force remains proportional to the torque applied to the control knob  6 , and at the same time maintains the desired direction of the pull wire  17  towards the proximal end of the guide tube  16 . It also aids in securing the attachment of the pull wire  17  to the operating member  7 . More specifically, a loop is preferably formed by drawing the remainder  17 ′ of the pull wire  17  back along itself towards the proximal end of the guide tube  16  attaching the remainder  17 ′ of the pull wire to the pull wire  17  itself, somewhere between the operation member  7  and the proximal end of the guide tube  16  as best seen in  FIGS.  4  and  5   . Attachment by crimping using an open or closed tube  22  is preferred, but the skilled person will know that other methods of attaching the pull wire  17  to itself could be used instead. Apart from the transition the outer cylindrical surface  23  is preferably smooth, i.e. without any grooves. Not having any groove maximizes the diameter of the cylindrical surface  23  and hence the lever, in turn, maximizing the displacement of the pull wire  17  and consequently the maximum deflection of the articulated tip part  36 . 
     For the proper function of the Bowden cable in the operation of the articulated tip part, it is of importance to have good control over the tension of the pull wires  17 . Both slack and over tension is undesired. 
     For this, the endoscope comprises a direction guide  24 . In the preferred embodiment the direction guide  24  is a cylindrical protrusion formed integrally with the anchoring block  15 , and thus in vicinity of the first location where the guide tube  16  is fixed with respect to the handle housing. As mentioned, the anchoring block  15  in preferred embodiment is generally a rectangular or square body member, i.e. a tile or a slab with two opposite large sides and four smaller sides connecting the large sides. As can best be seen in  FIG.  5    the cylindrical protrusion extends perpendicular from one of the large sides whereas the inlet passages  21  to the bores  20  are located on the opposite one of the large sides. The bores  20  extend between two of the smaller sides in a first plane between and generally parallel with the large sides. The bores  20  generally extend at an angle to each other so that each bore points towards a respective connection point  37  on either side of the diameter of the operation member  7 . The outer surface of the direction guide  24  comprises an outer surface extending essentially perpendicular to the first plane in which the at least one pull wire lies. In the preferred embodiment the mantle of the cylinder thus extends perpendicular to the large sides, and the first plane in which the bores  20  lie. 
     The projection of the mantle onto the first plane preferably coincides with the through bores  20 . If the bores  20  are straight, they thus form tangents to the circular projection of the mantle onto the first plane. It should however be noted that the bores  20  could be curved, and in that case the imaginary linear extension of the linear part of the pull wire  17  between the operating member and the proximal end of the guide tubes  16  should be tangential to the projection of the direction guide  24 . 
     During the assembly of the endoscope, the direction guide  24  serves to keep the direction and the tension on the part of the pull wire  17  which is drawn back along itself, i.e. the remainder  17 ′. More specifically the free end of the pull wire  17  is drawn past direction guide  24  and partially around it to secure the straight line from the attachment point  37  to the direction guide  24 . This is indicated by showing the remainder  17 ′ which will later be cut away, with the dashed lines in  FIG.  6   . From the direction guide  24  it is the remainder  17 ′ of the pull wire  17  drawn in another direction to a tensioning device where it is temporarily attached. The tensioning device ensures that the correct tension is on the pull wire  17  when the loop is secured by attaching the pull wire  17  to itself, e.g. by crimping the tube  22  onto it. Typical values of tension would be in the range of 1 N to 4 N. Also, the clamping mechanism leaves both hands of the assembly person free for the crimping operation etc. The free end of the pull wire  17  is then severed, and the remainder of the pull wire, i.e. the unused may be released from the clamping means. Preferably, one and the same direction guide  24  may be used for both pull wires  17 . That is to say the diameter of the cylinder is adapted to match the location of both bores  20 , so that for one bore  20  the pull wire  17  is drawn partially around the direction guide  24  in a clockwise sense, and for the other bore  20  the pull wire  17  is drawn partially around the direction guide  24  in the counter-clockwise sense. It is of course also possible to use more direction guides, e.g. one per bore  20 . Furthermore, it is of course not excluded to use only one direction guide  24  and draw both the pull wires around it in the same direction. This of course would give a less accurate direction of the pull wires during attachment, but in some configurations this tradeoff may be acceptable. One such configuration could be a direction guide  24  with a smaller diameter of the cylinder, not matching any of the locations of the bores  20 . 
     According to a further preferred embodiment the operating member may be held in a novel bearing arrangement. This novel bearing arrangement, which is best seen in  FIGS.  6  to  8   , may be implemented in an endoscope handle independently of the way the guide tube  16  is secured to the handle housing and the full wires tensioned and directed towards the operating member. 
     Turning, however, first to  FIG.  5    a bifurcated post  27  can be seen. Another similar bifurcated post  27  visible in  FIG.  8    is arranged on the other side of the operating member  7 . The bifurcation of the post  27  is provided by a recess provided in the free end of each post. The recess is adapted to receive a bearing element  28  made from a suitable low friction material, i.e. selected to provide low friction for the shaft  30  of the operating member  7 . One example of a suitable material could be POM (Polyoxymethylene). The bearing element  28  has a blind cylindrical hole  29  adapted to receive one end of the shaft  30  of the operating member. The shaft  30  is preferably made integrally with the operating member  7  and of the same material, e.g. by injection molding, so that it rotates with the operating member  7 . The bearing element  28  has suitable protrusion  31  engaging on either side of the bifurcated post  27  so as to prevent translatory movement with respect to the bifurcated post  27  in the axial direction of the shaft  30 . Alternatively or additionally, the bearing member has suitable protrusions  32  engaging on either side of a rib  33  provided on the inside wall of the main body part  4 . The engagement between the protrusions  32  and the rib  33  prevents rotary movement of the bearing element  28  with respect to the main body part  4  and in particular with respect to the bifurcated post  27 . It is thus ensured that the shaft  30  does not rotate the bearing element  28 , but rather rotates itself in the bearing element  28  so that the selected frictional properties are utilized in full. If not, unnecessary noise and undesired tactile feedback could be produced when the operating member  7  is turned by the thumb of the operator, in turn, leading to a sensation of reduced quality of the endoscope for the operator. 
     For the same reason the dimensions of the shaft  30  and the bearing elements  28  are carefully taken into account in order to prevent any play. More specifically the length of the shaft  30  is slightly longer than the distance between the bottoms of the blind holes  29  in the bearing elements  28  when the latter are properly located in the bifurcated posts  27 . Thus the bifurcated posts  27  will be bent slightly away from the operating member  7  in an elastic manner leaving no play between the shaft  30  and the bearing elements  28 . Likewise, the dimensions of the part of the bearing elements  28  located between the bifurcated posts  27  and the main body part  4  is also slightly larger than the distance between the inside wall of the main body part  4  and the bearing part where they engage each other, so that the bearing elements  28  press walls of the main body parts slightly apart in the assembled state. The elasticity of the main body part  4  thus aids in pressing the bearing elements  28  into the engagement with the shaft  30 . 
     The skilled person will understand that the invention as described above is not limited to the exemplary embodiments but many variations and implementations are possible without deviating from the scope of the claims. In particular features of embodiments may be implemented separately or in combination. Also, different dimensions and materials may be selected for purpose specific endoscopes and the like. In particular, the skilled person will understand that the extensive use of glued parts entails low manufacturing costs, in turn rendering the endoscope suitable for single use. In this respect it should be noted that single use means the use involving one single patient, and in particular does not imply that the endoscope may only be used in one single procedure involving the person. It may thus very well be used repeatedly for the same or different procedures involved in an examination and/or treatment of a patient.