Bendable tube for use with an endoscope - Patent application

Abstract

Disclosed herein is a tube for use in an endoscope. The tube comprises a plurality of elements disposed along a centerline of the tube. The elements are pivotally connected to one another by a plurality of joints. The joints allow the tube to bend relative to a default configuration of the tube. Each of the joints comprises a joint head on a respective first element of the plurality of elements and a joint socket on a respective second element of the plurality of elements, the joint socket configured to receive the joint head. The joint socket and joint head are shaped such that when the first element is pivoted relative to the second element from a default articulation angle of the joint associated with the default configuration to a target articulation angle, a first contact surface on the joint head engages a second contact surface on the joint socket to urge the joint head outwardly from the joint socket.

Description

[Technical field]

[0001] The present disclosure is in the field of medical technology. In particular, the present disclosure relates to a bendable tube for use in an endoscope that includes multiple elements pivotally connected to one another by multiple joints. [Background technology]

[0002] An endoscope is a surgical device that may be used to access (e.g., view or remove) or treat tissue within a patient's body by inserting one or more medical tools into the body through a body incision or body opening. The endoscope may include an interface / control and an insertion tube coupled to the interface / control. The insertion tube is configured to be inserted into the patient's body and may include one or more conduits for providing access to tissue within the body. The one or more conduits may be configured, for example, to receive medical tools and / or fluids and direct the medical tools and fluids, respectively, to the tissue of interest.

[0003] The insertion tube may be bendable to facilitate insertion into the patient's body. For this purpose, the insertion tube may, for example, include one or more passively and / or actively bendable parts (also referred to as passive and active bending parts, respectively). The passively bendable parts may, for example, be made of a bendable or flexible material or structure that can be deformed by applying an external force. The actively bendable parts may include a number of joints that can be articulated, for example for actively navigating the tip of the endoscope at the distal end of the insertion tube. Each of the joints may, for example, include a circular joint head arranged in a circular joint socket such that the joint head can rotate relative to the joint socket, thereby allowing bending of the insertion tube. Tubes with actively bendable parts are known, for example, from WO 2018 / 029917 A1 and US 2015 / 0164305 A1.

[0004] However, such actively bendable sections may be mechanically unstable, since the joints may have a tendency to align in a zigzag pattern with adjacent joints tilting in opposite directions. This may lead to reduced stability against side loads, as well as reducing the effective inner cross-sectional area of ​​the insertion tube. The available space in the tube may be further reduced, since it is necessary to place means for controlling the joints, such as control wires. Furthermore, a clearance between the joint head and the socket may be required to prevent the joint from jamming. This may reduce the efficiency of the torque propagation along the tube, since the clearance may first need to be compensated for before the torque can be transmitted by the joint. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2018 / 029917(A1) Brochure [Patent Document 2] US Patent Publication No. 2015 / 0164305(A1) Summary of the Invention [Problem to be solved by the invention]

[0006] It is therefore a feature of the present disclosure to provide a tube for use in an endoscope that exhibits improved mechanical stability and efficient torque transmission while also providing sufficient space within the tube. [Means for solving the problem]

[0007] The present disclosure provides a tube for use in an endoscope, as set out in the accompanying independent claims, examples of which are detailed in the dependent claims.

[0008] A tube according to the present disclosure is configured for use in an endoscope. The tube includes (i.e., includes, but is not limited to) a plurality of elements disposed along a centerline of said tube. The elements are pivotally connected to one another by a plurality of joints that allow the tube to bend relative to a default configuration of the tube. Each of the joints includes a joint head on a respective first element of the plurality of elements and a joint socket on a respective second element of the plurality of elements, the joint socket configured to receive the joint head. The joint socket and joint head are shaped such that when the first element is pivoted relative to the second element from a default articulation angle of the joint associated with said default configuration to a target articulation angle, a first contact surface on the joint head engages a second contact surface on the joint socket to push the joint head outwardly from the joint socket such that a displacement of the joint head along said centerline of the tube relative to its position at the default articulation angle is greater than zero for any target articulation angle.

[0009] The tube may extend from a proximal end to a distal end of the tube. As used herein, the term "proximal" may refer to an element, feature, or location along the length of the tube that is closer to a physician or other medical personnel during use of the endoscope (i.e., closer to the interface / controls of the endoscope), and the term "distal" may refer to an element, feature, or location along the length of the tube that is examined or treated within a patient's body during use of the endoscope (e.g., further away from the interface / controls of the endoscope). A direction along the centerline of the tube (e.g., from the proximal end to the distal end) may hereinafter be referred to as a longitudinal or axial direction. A direction along the circumference of the tube (e.g., parallel to the surface, e.g., outer surface, of the tube and perpendicular to the longitudinal direction) may hereinafter be referred to as a circumferential or azimuthal direction. A direction perpendicular to the surface, e.g., outer surface, of the tube (e.g., perpendicular to the longitudinal and circumferential directions) may hereinafter be referred to as a radial direction. The longitudinal, circumferential, and radial directions may, for example, define a cylindrical coordinate system. Depending on the condition or configuration of the tube, the orientation of these directions may change along the length of the tube, for example as a result of curvature of the tube.

[0010] The elements (hereinafter also referred to as pipe elements) may be, for example, annular or tubular elements. The elements may have, for example, pipe openings that may together form a pipe channel (or lumen) of the pipe when the elements are connected by a joint. In some examples, some or all of the elements may have the same shape and / or physical dimensions, and in particular may be identical elements (e.g. elements made of the same material and having the same shape and physical dimensions). The pipe elements may be arranged along the longitudinal direction, for example in a chain as detailed below. The pipe elements may be arranged in one or more portions along the length of the pipe (i.e. between the proximal and distal ends of the pipe), for example at an active bending section at or adjacent to the distal end of the pipe. In some examples, some or all of the pipe elements may be connected to each other directly via joints, i.e. without any additional members or elements therebetween. In other examples, one or more additional elements or members of pipe may be disposed between adjacent pipe elements, and the additional elements or members may, for example, be rigidly connected between adjacent pipe elements and / or may be pivotally connected between adjacent pipe elements by a joint or hinge different from the joints according to the present disclosure (e.g., by a joint having a circular joint head and a circular joint socket).

[0011] A tube centerline may extend along the center of the tube or along the center of the conduit, or may be disposed within the tube. The centerline may be, for example, a line or path connecting the centers of the tube's outer or inner circumferences (e.g., center of gravity) along the length of the tube. Depending on the condition or configuration of the tube, the tube centerline may not be a straight line, but may, for example, follow a curved path.

[0012] The tube elements are pivotally connected to each other by a plurality of joints such that adjacent elements can be pivoted (e.g., tilted or rotated) relative to each other. This allows the tube to be bent (or deformed) relative to its default configuration. The default configuration may be, for example, a configuration or state that the tube would ideally assume when a uniform tension or force is applied along the length of the tube, for example between the proximal and distal ends of the tube (e.g., without bias in a particular direction). In some examples, the default configuration may be a configuration or state that the tube would ideally assume when no external tension or force is applied to the tube (e.g., when no means for actuating the joints, such as control wires, are actuated). The default configuration may be associated with a predefined bending radius that the tube or a portion thereof assumes when the tube is in the default configuration. The default configuration may in particular be a straight configuration (corresponding to an infinite bending radius), i.e. the tube may be straight or substantially straight in the default configuration.

[0013] Each of the joints is configured to pivotally connect a respective first element (e.g., a respective proximal or distal element) to a respective second element (e.g., a respective distal and proximal element). To this end, a joint head on the respective first element may be at least partially received in a joint socket on the respective second element. The joint head may, for example, be a protuberance or projection on the first element, which may, for example, extend in the longitudinal direction. The joint socket may, for example, be a corresponding notch or recess on the second element, in which the joint head or a part thereof may be located. The joint socket and the joint head each include a first and a second contact surface configured to engage with each other (e.g., to contact each other) to enable articulation of the joint, for example by moving or sliding the first contact surface along the second contact surface.

[0014] In the default configuration, each joint assumes a respective default articulation angle, which in some examples may be the same default articulation angle (i.e., the default articulation angles of some or all of the joints may be equal, e.g., 0°). The articulation angle may be, for example, the angle at which the first and second elements are disposed relative to one another (e.g., the angle at which the first element is angled relative to the second element). A default articulation angle of 0° may correspond, for example, to a configuration in which the respective first and second elements are straight or parallel to one another.

[0015] The joint socket and head of each of the joints are configured such that when the first element is rotated relative to the second element away from the respective joint's default articulation angle, the joint head is at least partially pushed out of the joint socket (e.g., along a longitudinal / centerline). In other words, the movement of the joint head not only constitutes a fixed rotation or rotation about an articulation axis (i.e., cannot be resolved into a pure rotation about the same axis of rotation at all articulation angles), but additionally includes a translation out of the joint socket.

[0016] This causes the joint head to be displaced (e.g., along a centerline) at its default position at the default articulation angle of the respective joint when viewed from the joint socket (e.g., in the joint socket's frame of reference). This can move or push the first element away from the second element (e.g., separating the first and second elements or separating them further relative to each other) such that the joint and thereby the tube extends slightly longitudinally. In other words, the joint socket and head are configured such that the length of the tube (e.g., the length of the centerline between the proximal and distal ends) increases when the joint is rotated away from its default articulation angle.

[0017] The joint socket and head are shaped such that the displacement of the joint head along the centerline relative to its position at the default articulation angle is greater than zero at any target articulation angle (e.g., at any target articulation angle other than the default articulation angle). In other words, the displacement of the joint head (and therefore the length of the tube) exhibits a global minimum at the default articulation angle. This may, for example, bias the tube towards a default configuration such that the tube preferably assumes the default configuration when, for example, the tube is under uniform longitudinal tension. The displacement of the joint head along the centerline may be measured by projecting onto the centerline a line connecting corresponding points on the joint head at the default articulation angle and the respective target articulation angle. Said point on the joint head may, for example, be the center of gravity or center of mass of the joint head, or a point on the joint head through which the articulation axis of the joint extends at the default articulation. The displacement may increase from the default articulation angle by, for example, between 0.1 μm and 0.1 mm, in some examples between 0.5 μm and 50 μm, and in one example between 1 μm and 10 μm per degree of articulation. The displacement of the maximum articulation angle of the joint (e.g., at one or both ends of the joint's range of motion) may be, for example, between 2 μm and 1 mm, in some examples between 5 μm and 0.5 mm, in one example between 20 μm and 0.2 mm, and in one example between 0.10 mm and 0.15 mm.

[0018] In some examples, the first contact surface includes a protruding portion protruding from the inscribed circle of the first contact surface, and / or the second contact surface includes a recessed portion recessed from the inscribed circle of the second contact surface. In other words, one or both of the joint head and the joint socket may be non-circular, i.e., at least a portion thereof may deviate from a circular shape or cross section (when viewed perpendicular to the longitudinal direction), the joint head including a protruding portion compared to a circular shape, and the joint socket including a recessed portion compared to a circular shape. The protruding portion may protrude from the inscribed circle of the first contact surface by, for example, 2% to 30%, in some examples 4% to 20%, and in one example 6% to 15% of the radius of the inscribed circle of the first contact surface. Additionally or alternatively, the protruding portion may protrude from the inscribed circle of the first contact surface by, for example, about 5 μm to 0.5 mm, in some examples 20 μm to 0.2 mm, and in one example 0.10 mm to 0.15 mm. The recessed portion may be recessed from the inscribed circle of the second contact surface by, for example, 3% to 50%, in some cases 5% to 30%, and in one example 10% to 20% of the radius of the inscribed circle of the second contact surface. Additionally or alternatively, the recessed portion may be recessed from the inscribed circle of the second contact surface by, for example, 10 μm to 1 mm, in some cases 30 μm to 0.3 mm, and in one example 0.15 mm to 0.2 mm.

[0019] The inscribed circle of a contact surface as used herein may be, for example, a circle to which at least two non-adjacent portions of the respective contact surface (e.g., respective opposite portions of the joint head and socket) are tangent. The inscribed circle may be in a plane perpendicular to the radial direction of the tube and / or in a plane perpendicular to the articulation axis of the joint. In some examples, said at least two non-adjacent portions may be portions of the respective contact surfaces that contact the other contact surface when the first element is at the default articulation angle. The inscribed circle may, for example, connect points on said portions of the respective contact surfaces, in particular the centers of said portions of the respective contact surfaces. In one example, the inscribed circle may be the largest circle to which at least two non-adjacent portions of the respective contact surfaces are tangent, said two non-adjacent portions contact the other contact surface when the first element is at the default articulation angle.

[0020] The protruding portion and the recessed portion may be positioned on the respective contact surfaces such that the protruding portion of the first contact surface faces the recessed portion of the second contact surface when the first element is at the default articulation angle. In other words, when the first element is at the default articulation angle, the protruding portion on the joint head may be positioned within the recess of the joint socket. This allows the joint head to be positioned further into the joint socket than at other articulation angles.

[0021] When the first element is rotated from the default articulation angle to the target articulation angle, the protruding portion may engage the second contact surface to urge the joint head outwardly from the joint socket. For example, the protruding portion may contact the second contact surface (e.g., a non-recessed portion thereof), which may further urge the joint head from the joint socket. The non-circular shape of the joint head and joint socket may prevent pivoting or rotation of the joint about a fixed articulation axis and may additionally induce translation of the joint head relative to the joint socket, as described above.

[0022] In some examples, the first contact surface may include a first linear portion and a second linear portion that extends at an angle relative to the first linear portion. Additionally or alternatively, the second contact surface may include a third linear portion and a fourth linear portion. As used herein, a linear portion of a contact surface may be, for example, a portion that has one or both principal curvatures equal to zero (i.e., a portion that exhibits no curvature in at least one direction, e.g., a concave / convex ellipsoidal portion or a planar portion). For example, one or both of the joint head and the joint socket may have a triangular or V-shape or cross-section having a pair of linear edges or surfaces that extend at an angle relative to each other (e.g., when viewed along the articulation axis of the joint and / or along a radial direction). The first and second linear portions of the first contact surface may be positioned such that the first and second linear portions each contact a respective linear portion (e.g., the third or fourth linear portion) of the second contact surface when the first element is at the default articulation angle. This may, for example, allow for establishing line or planar contact rather than point contact between the first and second contact surfaces at the default articulation angle, which may provide a robust and well-defined contact, especially when considering manufacturing tolerances.

[0023] The protruding portion of the first contact surface may be disposed between the first and second linear portions of the first contact surface. In some examples, the first and second linear portions of the first contact surface may be tangent to the inscribed circle of the first contact surface. Additionally or alternatively, the recessed portion of the second contact surface may be disposed between the third and fourth linear portions of the second contact surface. In some examples, the third and fourth linear portions of the second contact surface may be tangent to the inscribed circle of the second contact surface. For example, one or both of the joint head and the joint socket may have a flat-topped triangular or V-shape or cross-section with a flat or rounded tip. The flat or rounded tip may form the protruding portion and the recessed portion of the corresponding contact surface, respectively.

[0024] In some examples, the joint socket and the joint head are shaped such that as the first element is rotated from a default articulation angle to a target articulation angle that differs from the default articulation angle by more than 10°, in some examples by more than 20°, in one example by more than 30°, the displacement of the joint head along a centerline of the tube relative to its position at the default articulation angle increases monotonically, in one example strictly monotonically. The displacement may, for example, increase monotonically, in one example strictly monotonically, up to a target articulation angle that differs from the default articulation angle by 10° to 75°, in some examples by 20° to 60°, in one example by 30° to 50°. Additionally or alternatively, said displacement of the joint head may increase monotonically, in one example strictly monotonically, as the first element increases from the default articulation angle to a maximum articulation angle of the joint (e.g. the displacement may increase monotonically or strictly monotonically throughout the entire operable range of the joint). In other words, at any articulation angle, the displacement of the joint head (and therefore the length of the tube) may decrease when rotating the first element towards the default articulation angle, but the displacement may increase when rotating the first element from the default articulation angle towards the maximum articulation angle.

[0025] In some examples, the joint socket and the joint head are shaped such that when the first element is at the default articulation angle, a tip of the joint head is separated from the joint socket by a gap. For example, the protruding portion of the first contact surface and the recessed portion of the second contact surface may be shaped such that when the first element is at the default articulation angle, the protruding portion is separated from the joint socket by a gap. The gap may be, for example, between 5 μm and 0.5 mm, in some examples between 10 μm and 0.1 mm, and in one example between 40 μm and 60 μm.

[0026] In some examples, the joint socket may be configured to allow the joint head to be removed from the joint socket along the centerline of the tube. For example, the width of the opening of the joint socket may be greater than the maximum width of the joint head (e.g., along the circumferential direction) such that the joint head can freely enter and exit the joint socket through said opening. Such an open joint shape, where the joint head is not trapped in the joint socket, may allow the joint head to leave the joint socket when, for example, excessive force is applied to the tube, thus preventing damage to the joint in some examples. During normal use (e.g., without applying excessive force), the joint head may be held in the joint socket by a means for actuating the joint, such as a control wire, which may be configured to apply, for example, a uniform compressive tension in the longitudinal direction when not actuated.

[0027] In some examples, the joint socket and / or the joint head include a lateral mechanical stop configured to limit movement of the joint head in a direction parallel to the articulation axis of the joint (e.g., radially). The lateral mechanical stop may be or may include one or more lateral side walls of the joint socket (e.g., an inner lateral side wall and / or an outer trailing side wall of the joint socket), which may, for example, be located on the inner and / or outer periphery of the respective element. The one or more lateral side walls may be configured to contact the joint head when the joint head is moved parallel to the articulation axis to prevent the joint head from leaving the joint socket in the lateral direction. Additionally or alternatively, a lateral mechanical stop may also be provided on the joint head, for example a lateral mechanical stop extending from the joint head along the inner and / or outer side of an adjacent element that includes a corresponding joint socket.

[0028] In some examples, one or more joints of the plurality of joints may have a maximum articulation angle that is different from the maximum articulation angles of other joints of the plurality of joints. This may enable, for example, implementing a non-uniform bending profile, e.g., a bending profile having a non-uniform bending radius (i.e., deviating from a circular shape). For example, the plurality of joints may include two or more groups of joints, each of which may have a respective maximum articulation angle (e.g., associated with a respective minimum bending radius). The plurality of joints may, for example, include a first group of joints (including one or more joints) having a first maximum articulation angle and a second group of joints (including one or more joints, e.g., all of the joints not included in the first group) having a second maximum articulation angle that is different from the first maximum articulation angle. The first maximum articulation angle may be, for example, 1.25 to 10 times, and in some examples 1.5 to 3 times, the second maximum articulation angle, or vice versa. The first and second maximum articulation angles may differ from each other, for example, by 2° to 30°, and in one example, by 5° to 20°. In some examples, the maximum articulation angles of the joints may vary continuously along the length of the tube. The maximum articulation angles may increase (or decrease) monotonically, in one example strictly monotonically, along the length of the tube, such that, for example, the maximum articulation angle of any given joint is greater than the maximum articulation angle of the proximally (or distally) adjacent joint. Different maximum articulation angles may be achieved, for example, by providing angled end faces on elements that extend at different angles, as described in more detail below. In other examples, all joints may have the same maximum articulation angle.

[0029] In some examples, the tube elements are arranged in a chain, e.g., in a serial arrangement where each of the tube elements (apart from the outermost elements) is connected to a respective proximal element by a respective proximal joint and to a respective distal element by a respective distal joint. In some examples, the outermost joint at one or both ends of the chain may have a smaller maximum articulation angle than the other joints in the chain. For example, the maximum articulation angle of the outermost joint at one or both ends of the chain may be between 10% and 70%, in some examples between 20% and 50%, in one example between 25% and 45% (e.g., 1 / 3), and in one example between 50% and 70% (e.g., 2 / 3) of the maximum articulation angle of the other joints in the chain. In some examples, the other joints in the chain all have the same maximum articulation angle.

[0030] For each of the joints, the first element can include a first beveled end surface and the second element can include a second beveled end surface facing the first beveled end surface. The first and second end surfaces can be configured to contact one another when the joint reaches its maximum articulation angle (e.g., functioning as an axial or longitudinal mechanical stop) to prevent further articulation of the joint. When the joint is not at its maximum articulation angle, the first and second end surfaces can be spaced apart to allow articulation of the joint. In a default configuration, the first and second end surfaces can each extend at a respective angle relative to a plane perpendicular to the centerline of the tube. The first and second beveled end surfaces can be inclined in opposite directions, e.g., such that the sign of the angle of the first beveled end surface is opposite to the sign of the angle of the second beveled end surface. In some examples, respective contact features, such as protrusions or projections, can be disposed on or formed by the first end surface and / or the second end surface. The contact feature may be configured to contact the other end surface, e.g., a contact feature on the other end surface, when the joint reaches its maximum articulation angle, e.g., to provide a well-defined contact point.

[0031] The angle between the first and second end faces associated with the outermost joints at one or both ends of the chain may be less than the angle between the first and second end faces associated with the other joints in the chain when the respective joints are at the default articulation angle. The angle between the first and second slanted end faces in the default configuration may define (e.g., correspond to) the maximum articulation angle. The angle between the first and second end faces associated with the other joints in the tube may be, for example, between 25° and 55°, and in one example, between 35° and 45°. The angle between the first and second end faces associated with the outermost joints at one or both ends of the tube may be, for example, between 5° and 45°, and in one example, between 5° and 20° (e.g., 1 / 3 of the angle between the first and second end faces associated with the other joints), and in one example, between 25° and 35° (e.g., 2 / 3 of the angle between the first and second end faces associated with the other joints).

[0032] In some examples, some or all of the tube elements include guide elements configured to guide control wires for actuating the multiple joints. The guide elements may be or include, for example, grooves, notches, clips, hooks, and / or holes into which the control wires may be positioned.

[0033] In some examples, the tube may also include a control wire, which may be disposed within said guide element of the tube element. The control wire may be configured, for example, to apply a compressive tension to the tube or a portion thereof, particularly the portion including the tube element, e.g., along a longitudinal direction from the distal end to the proximal end, when actuated. The control wire may be connected or attached to a distal attachment point, which may, for example, be disposed distally of the tube element, e.g., at or adjacent to the distal end or tip of the tube. Pulling on the proximal end of the control wire may generate a force from the distal attachment point toward the proximal end of the tube. In some examples, the control wire may also be configured to apply a compressive tension even when not actuated, e.g., to bias the tube toward a default configuration and / or to secure the joint head in the joint socket.

[0034] The guide elements may be disposed, for example, on the outer periphery of each element, for example on the outer surface of the element facing away from the central opening of the element (i.e., facing radially outward from the centerline of the tube). The guide elements may be particularly disposed such that, when disposed within the guide elements, the control wires are disposed outside the tube, i.e., neither in nor facing the central opening. This may, for example, increase the available space inside the tube.

[0035] In one example, the guide element is configured to guide the control wire such that the control wire is disposed adjacent to an inner or outer side of a joint head on the respective element or on an adjacent element. The guide element may, for example, be aligned with a joint head or joint socket on the respective element along a circumferential direction such that, when disposed within the guide element, the control wire extends, for example, adjacent to the respective joint, for example through or adjacent an actuation axis of the joint. A control wire disposed adjacent to an inner or outer side of a joint head may, for example, provide a lateral mechanical stop for the respective joint head, for example to prevent said joint head from leaving the joint socket in a radial direction.

[0036] In some examples, some or all of the elements are each pivotally connected to a respective first adjacent element (e.g., a respective proximal element) by a respective first pair of joints disposed on either side of the tube. The first pair of joints may be displaced, for example, by 150° to 210°, and in one example, 170° to 190°, relative to one another along the circumferential direction. In some examples, some or all of the first pair of joints may be disposed in the same plane, for example to allow bending of the tube in a first articulation direction or a first articulation plane.

[0037] Additionally or alternatively, some or all of the elements (particularly some or all of said elements pivotally connected to respective first adjacent elements by respective first pair of joints) are each pivotally connected to respective second adjacent elements (e.g. respective distal elements) by respective second pair of joints arranged on either side of the tube. The second pair of joints may be displaced, for example, by 150° to 210°, in one example 170° to 190°, relative to each other along the circumferential direction. In some examples, some or all of the second pair of joints may be arranged in the same plane, for example to allow bending of the tube in a second articulation direction or in a second articulation plane.

[0038] The first and second pairs of joints may be displaced relative to one another along the circumferential direction of the tube by 75° to 105°, in some examples 80° to 100°, and in one example 85° to 95° (e.g., 90°). In other words, on each corresponding tube element, the joint heads and / or sockets associated with the respective first and second pairs of joints may be arranged alternately and equidistantly or substantially equidistantly along the circumferential direction, e.g., displaced 90° from adjacent joint heads and / or sockets. Thus, the first and second articulation directions / planes may be orthogonal or substantially orthogonal to one another.

[0039] Some or all of the tube elements pivotally connected to respective adjacent elements by first and second pairs of joints may each include four guide elements arranged along the circumference of the respective element, each of the four guide elements configured to guide a respective control wire. Each of the four guide elements may be displaced from an adjacent joint along the circumference of the tube by 35° to 55°, in some instances 40° to 50° (e.g., 45°). In other words, each of the guide elements may be positioned approximately midway between two of the joints associated with the respective tube element (i.e., between the respective first pair of joints and the respective second pair of joints). In some instances, two of the guide elements may be positioned in a first wire plane and the other two guide elements may be positioned in a second wire plane. The first and second wire planes may be at an angle of 35° to 55°, in some instances 40° to 50° (e.g., 45°) with respect to the first and second articulation planes. Because the wire planes are not aligned with the articulation directions / planes, actuation of each of the control wires can actuate all of the joints simultaneously, which can, for example, cause tubes to bend in their respective wire planes.

[0040] In other examples, each of the four guide elements may be aligned with a corresponding joint along the circumferential direction, such as such that the wire plane is aligned with the articulation direction / plane, in which case actuation of each of the control wires may only actuate either the first pair of joints or the second pair of joints, resulting in bending of the tube in the respective articulation direction / plane.

[0041] Each of the pipe elements may extend around a respective conduit opening as described above, for example, such that the sidewall of each pipe element encloses or surrounds the respective conduit opening along the circumferential direction. The conduit openings may have a circular or substantially circular cross section perpendicular to the centerline of the pipe. For example, the diameter of the conduit openings may vary by less than 25% (e.g., 0% to 25%, in some instances 5% to 25%, in one instance 10% to 25%), preferably less than 15%, in one instance less than 10%, along the circumference of the respective element. The variation in diameter of the conduit openings may be defined, for example, as the ratio of the difference between the maximum and minimum diameters to the average diameter of the conduit opening. The pipe elements may have a smooth inner surface along their inner circumference. For example, the minimum radius of curvature of the inner surface in a plane perpendicular to the centerline may be 10% or more (e.g., 10% to 100%), in some cases 20% or more (e.g., 20% to 100%), in one case 30% or more (e.g., 30% to 100%), and in one case 40% or more (e.g., 40% to 100%) of the average radius of the conduit opening.

[0042] The tubes according to the present disclosure are configured for use in endoscopes. The tubes may be configured for use in, for example, but not limited to, bronchoscopes, sinusoscopes, nasopharyngoscopes, laryngoscopes, laparoscopes, gastroscopes, duodenoscopes, colonoscopes, echoscopes, hysteroscopes, cystoscopes, ureteroscopes, urethroscopes, cardioscopes, and arthroscopes. The length, diameter, and / or stiffness / bendability of the tubes may be selected accordingly.

[0043] The tube may be, for example, an insertion tube for use in an endoscope, or a portion of an insertion tube for use in an endoscope. In one example, the tube is a hypotube for use in an endoscope. The hypotube may be configured to be surrounded or enclosed by a tubular sleeve or cover, for example, to form the insertion tube. The hypotube may form a framework or skeleton of the insertion tube, for example, configured to provide dimensional stability to the insertion tube.

[0044] The present disclosure further provides an endoscope including a tube according to any one of the examples described herein. The tube may be, for example, an insertion tube or part thereof, particularly a hypotube, of the endoscope. The endoscope may further include an interface / control unit configured to be coupled to the tube.

[0045] In the following, a detailed description of the present disclosure and examples thereof will be given with reference to the drawings, which show the following schematic diagrams: [Brief description of the drawings]

[0046] [Figure 1] FIG. 1 illustrates an endoscope according to an example of the present disclosure. [Figure 2a] FIG. 1 illustrates a joint having a joint head and a joint socket according to an example of the present disclosure. [Figure 2b] FIG. 2b shows the joint of FIG. 2a at the default articulation angle. [Figure 2c] FIG. 2b shows the joint of FIG. 2a at a first target articulation angle. [Figure 2d] FIG. 2b shows the joint of FIG. 2a at a second target articulation angle. [Figure 3a] FIG. 1 is a side view of a pair of pipe elements having a joint head and a joint socket according to an example of the present disclosure. [Figure 3b] FIG. 3b shows an enlarged view of the joint head and joint socket of the pipe element of FIG. 3a. [Figure 3c] FIG. 3b is a front view of one of the pipe elements of FIG. 3a. [Figure 3d] FIG. 3b is a rear view of one of the pipe elements of FIG. 3a. [Figure 3e] FIG. 3b is a perspective view of one of the pipe elements of FIG. 3a. [Figure 4a] FIG. 1 is a first side view of an active bending section of a tube for use in an endoscope according to an example of the present disclosure. [Figure 4b] FIG. 4b is a second side view of the active bending portion of FIG. 4a. [Figure 5a]FIG. 13 is a side view of a pair of pipe elements having a joint head and a joint socket according to another example of the present disclosure. [Figure 5b] FIG. 5b is a perspective view of one of the pipe elements of FIG. 5a. [Figure 5c] FIG. 5b is a front view of one of the pipe elements of FIG. 5a. [Figure 5d] FIG. 5b is a rear view of one of the pipe elements of FIG. 5a. [Figure 5e] FIG. 5b is another perspective view of one of the pipe elements of FIG. 5a. [Figure 6a] FIG. 13 is a first side view of an active bending section of a tube for use in an endoscope according to another example of the present disclosure. [Figure 6b] FIG. 6b is a second side view of the active bending portion of FIG. 6a. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0047] 1 illustrates a schematic diagram (not to scale) of an endoscope 100 according to one example of the present disclosure. Endoscope 100 includes an interface / control unit 102 having a connector 104 and one or more ports 106.

[0048] The connector 104 is configured to connect or attach the tube 200 to the interface / control 102, which may be removably connected or attached in some examples. The tube 200 extends along a centerline 201 of the tube 200 from a proximal end 200A to a distal end 200B, where the proximal end 200A is adjacent to the interface / control 102 (e.g., connected or attached thereto via the connector 104) and the distal end 200B faces away from the interface / control 102. A direction X along the centerline 201 from the proximal end 200A to the distal end 200B may hereinafter be referred to as a longitudinal direction, an axial direction, or an X direction. A direction φ along the circumference of the tube (e.g., parallel to the surface of the tube and perpendicular to the longitudinal direction X) may hereinafter be referred to as a circumferential direction, an azimuthal direction, or a φ direction.

[0049] The one or more ports 106 may include one or more fluid ports in fluid communication, e.g., with an interior of the tube 200, e.g., a conduit (not shown) formed by or disposed within the tube 200, e.g., via the connector 104. Additionally or alternatively, the one or more ports 106 may include one or more light conductor ports, each of which may be configured, e.g., to receive a light conductor (not shown) disposed within the tube 200 and / or provide coupling with a light conductor (not shown) disposed within the tube 200, e.g., a conduit formed by or disposed within the tube 200. The interface / control unit 102 may further include one or more electrical contacts (not shown), which may be disposed or connected to the distal end 200B of the tube 200, e.g., to provide electrical connection to the interior of the tube 200, the distal end 200B of the tube 200, and / or the distal tip (not shown) of the endoscope 100. The interface / control unit 106 may also include means for actuating the distal portion 200-II of the tube 200, such as one or more control knobs (not shown), which may be configured to apply tension to one or more control wires (not shown) coupled to the distal portion 200-II, such as via one or more attachment points at the distal end 200B.

[0050] The interface / control section 102 may be embodied as a single unit as shown in FIG. 1, or as two or more separate units, e.g., a control portion and an interface portion, where the control portion may be connected to the proximal end 200A of the tube 200, e.g., via a connector 104, and the interface portion may be connected to the control portion, e.g., via a flexible or supply tube.

[0051] The tube 200 may be a tube for use in an endoscope according to any one of the examples described herein. In the example of FIG. 1, the tube 200 includes a first or proximal portion 200-I and a second or distal portion 200-II. The proximal portion 200-I may be or include one or more passive bending portions (not shown) configured to bend or deform upon application of an external force, for example. The passive bending portions may be made of (e.g., may include), for example, a flexible material. Additionally or alternatively, the passive bending portions may be made of a rigid or semi-rigid material, such as a metal (e.g., stainless steel), and may include, for example, multiple bendable portions, each of which may be provided with one or more openings in a wall of the tube 200 to enhance the flexibility of the tube 200 within the respective bendable portion. In some examples, the proximal portion 200-I may also include a rigid portion (not shown) in addition to or instead of the one or more passive bending portions, for example at the proximal end 200A adjacent the connector 104. The length and diameter of the tube may be selected to suit the type of endoscope with which the tube 200 will be used. The tube 200 may have a length of, for example, 20 cm to 200 cm, and in some examples, 50 cm to 150 cm. The outer diameter of the tube 200 may be, for example, between 1 mm and 20 mm, and in some examples, between 2 mm and 10 mm.

[0052] In the example of FIG. 1, the distal section 200-II is or includes a bending section, in particular an active bending section, and therefore may also be referred to as the active bending section 200-II. The active bending section 200-II includes a number of elements 202 (hereinafter also referred to as tube elements 202) arranged along a centerline 201 of the tube 200. The tube elements 202 are pivotally connected to each other by a number of joints 204 so as to allow bending the tube 200, in particular the active bending section 200-II, relative to a default configuration of the tube 200. The default configuration may be, for example, a straight configuration as shown in FIG. 1, in which the tube 200 is not bent and the centerline 201 is straight. The default configuration may be, for example, a configuration that the tube 200 would ideally assume (e.g., without any external perturbation) when no additional tension is applied to the control wires, for example, such that the control wires generate a uniform (non-directional) compressive tension in the longitudinal direction. In some examples, the active bending portion 200-II may be actively actuated or controlled using corresponding means for actuating the active bending portion 200-II, such as, for example, control wires, etc. In other examples, the portion 200-II may be a passive bending portion, which may bend or deform under an external force, for example, that causes the joint to rotate.

[0053] Each of the joints 204 is configured such that when the elements 202 connected by the respective joints 204 are rotated relative to one another from a default articulation angle of the joints 204 associated with the default configuration (e.g., 0° in the example of FIG. 1) to a target articulation angle different from the default articulation angle (i.e., a non-zero angle in the example of FIG. 1), the joints 204 extend or stretch along the longitudinal direction to slightly increase the length of the tube 200 along the longitudinal direction, e.g., as described in more detail below with reference to FIG. 2a-2d. Each of the joints 204 may be embodied, for example, similarly to the joints of FIG. 2a-2d, FIG. 3a, FIG. 3b, and FIG. 5a. In the default configuration, the tube 200 (e.g., its centerline 201) may have its smallest longitudinal extent, i.e., its smallest length in the longitudinal direction. When a uniform tension is applied in the longitudinal direction, the tube 200 may tend to reduce or minimize its length and may assume the default configuration, i.e., straightened in the example of FIG. 1.

[0054] 2a to 2d show schematic diagrams (not to scale) of a tube joint 204 for use in an endoscope according to one example of the present disclosure. The joint 204 may be used to pivotally connect two elements 202 to each other, for example, in the tube 200 of FIG. 1. In the following, the tube 200 is used as a non-limiting example for illustrative purposes. The viewing direction in FIG. 2a to 2d may be parallel to the articulation axis of the joint 204, and may correspond, for example, to the radial direction of the tube 200.

[0055] The joint 204 includes a joint head 204B on a respective first element 202B (e.g., a distal element of the joint 204 closer to the distal end 200B of the tube 200) and a joint socket 204A on a respective second element 202A (e.g., a proximal element of the joint 204 closer to the proximal end 200A of the tube 200). The joint socket 204A is configured to receive the joint head 204B, as shown in Figures 2a to 2d. In Figure 2a, the joint 204 is shown with the joint head 204B removed from the joint socket 204A, for example when assembling the tube 200. In Figures 2b to 2d, the joint 204 is shown with the joint head 204B disposed within the joint socket 204A. In Figure 2b, the joint 204 is at its default articulation angle, e.g., 0° in this example, which corresponds to a straight centerline 201, while in Figures 2c and 2d, the joint 204 is at first and second target articulation angles, respectively, which are different from the default articulation angle, e.g., 10° in the example of Figure 2c, and 20° in the example of Figure 2d. Thus, the centerline 201 is bent or twisted in Figures 2c and 2d.

[0056] The joint head 204B includes a first contact surface 206B configured to slidably engage with a second contact surface 206A on the joint socket 204A when the joint head 204B is received in the joint socket 204B. The joint socket 204A and the joint head 204B, and in particular the first and second contact surfaces 206A, 206B, are shaped such that when the first element 202B is rotated relative to the second element 202A away from the default articulation angle, i.e. from the default configuration of FIG. 2b towards the configuration of FIG. 2c, the first contact surface 206B engages with the second contact surface 206A to push the joint head 204B outwardly from the joint socket 204A. This causes the joint head 204B to be displaced by a displacement D relative to its position at the default articulation angle of FIG. 2b such that the joint 204 extends or elongates slightly along the longitudinal direction when viewed from the joint socket 204A. This may cause the length of the tube 200 to increase by a displacement D. The joint head 204B and joint socket 204A are configured such that the displacement D is greater than zero at any target articulation angle (e.g., any non-zero articulation angle), i.e., such that the joint 204 (and therefore the tube 200) has its smallest longitudinal extent at the default articulation angle.

[0057] 2a-d, both the joint socket 204A and the joint head 204B have a non-circular cross-section perpendicular to the articulation axis of the joint 204 (e.g. perpendicular to the radial direction of the tube 200). In particular, the first contact surface 206B of the joint head 204B includes a protruding portion 208B that protrudes from an inscribed circle 210B of the first contact surface 206B. The second contact surface 206A of the joint head 204A includes a recessed portion 208A that is recessed from an inscribed circle 210A of the second contact surface 206A. In the example of Figures 2a-d, the inscribed circles 210A, 210B are defined such that they are perpendicular to the articulation axis of the joint 204 and that the portion of each contact surface 208A, 208B that is in contact with the other contact surface 208B, 208A at the default articulation angle is tangent to the inscribed circle 210A, 210B as shown in Figure 2b. At the default articulation angle, the center 212A of the inscribed circle 210A of the second contact surface 206A may be aligned with the center 212B of the inscribed circle 210B of the second contact surface 206B. The centers 212A, 212B may, for example, lie on the articulation axis of the joint 204 at the default articulation angle. The inscribed circles 210A, 210B may, for example, be the largest circles that can be inscribed in the first and second contact surfaces 206A, 206B, respectively, and are centered on the articulation axis of the joint 204 at the default articulation angle.

[0058] At the default articulation angle, the protruding portion 208B faces the recessed portion 208A and is separated from it by a gap 214. The gap 214 may have a width along the longitudinal direction of, for example, between 10 μm and 100 μm. When the first element 202B is rotated away from the default articulation angle, the protruding portion 208B contacts the second contact surface 206A, for example with its lateral portion adjacent to the recessed portion 206A. This causes the joint head 204B to be pushed outward from the joint socket 204A such that the joint head 204B is displaced along the center line 201 by a displacement D. The displacement D may be, for example, the distance by which the center 212B of the inscribed circle 210B of the first contact surface 206B is displaced from the center 212A of the inscribed circle 210A of the second contact surface 206A. In some examples, the displacement D may increase monotonically with articulation angle, for example with a variable of the difference between the target articulation angle and the default articulation angle. The displacement D may increase monotonically over a particular range of articulation angles (e.g., up to an articulation angle of at least 20°, and in some examples at least 30°), and / or over the entire movable range of the joint 204 (e.g., up to a maximum articulation angle of the joint 204).

[0059] The movement of the joint head 204B when rotating the first element 202B corresponds to a combination of rotation and translation. This movement results in a rotation or tilt of the first element 202B and thus of the corresponding part of the center line 201 by the articulation angle, as well as a displacement of the joint head 204B. Thus, the articulation axis of the joint 204 can shift when rotating the first element 202B and can be in a different position at each articulation angle. The articulation axis may not be tilted and may always remain parallel to its orientation, e.g., radial, at a default angle (i.e. it may be shifted or translated by a parallel offset).

[0060] FIG. 3a shows a schematic diagram of a pair of pipe elements 202A, 202B, each having a joint socket 204A and a joint head 204B, in a side view, according to an example of the present disclosure. The pipe elements 202A, 202B may be used, for example, in the pipe 200 of FIG. 1, which is used below as a non-limiting example for illustrative purposes. FIG. 3b shows an enlarged view of the joint socket 204A and the joint head 204B, which correspond to the dotted rectangle in FIG. 3a. In FIG. 3c and FIG. 3d, one of the pipe elements 202A, 202B is shown in a front view (e.g., along the longitudinal direction of the pipe 200 facing the proximal end 200A) and a rear view (e.g., along the longitudinal direction of the pipe 200 facing the distal end 200B), respectively. FIG. 3e shows one of the pipe elements 202A, 202B in a perspective view.

[0061] The tube elements 202A, 202B may be made of (e.g., including, i.e., including but not limited to) a semi-rigid or rigid material, particularly a metal such as stainless steel, titanium, or a nickel-titanium alloy such as Nitinol. In some examples, the tube elements 202A, 202B may be made of (i.e., including only) a semi-rigid or rigid material, particularly a metal such as stainless steel, titanium, or a nickel-titanium alloy such as Nitinol.

[0062] The joint socket 204A is configured to receive the joint head 204B to form an articulated joint 204. Similar to the joint of Figures 2a to 2d, the joint head 204B includes a first contact surface 206B having a protruding portion 208B protruding from an inscribed circle 210B of the first contact surface 206B. The joint socket 204A includes a second contact surface 206B configured to slidably engage with the first contact surface 206A to enable articulation of the joint 204. The second contact surface 206A includes a recessed portion 208A recessed from the inscribed circle 210A of the second contact surface 206A.

[0063] In the example of Figures 3a, 3b, the first contact surface 206B has a flat-topped triangular or V-shaped profile (e.g., a flat-topped triangular or V-shaped profile or contour in a plane perpendicular to the articulation axis of the joint 204). The first contact surface 206B includes a pair of straight portions 206B-I, 206B-II located on either side of the protruding portion 208B. The second contact surface 206A has a corresponding flat-topped triangular or V-shaped profile and also includes a pair of straight portions 206A-I, 206A-II located on either side of the recessed portion 208A. Each of the straight portions 206A-I, 206A-II, 206B-I, 206B-II is tangent to the inscribed circle 210A, 210B of the respective contact surface 206A, 206B. The inscribed circles 210A, 210B may extend through the centers of the respective straight segments 206A-I, 206A-II, 206B-I, 206B-II, as shown, for example, in FIG. 3b. When the joint head 204B is received in the joint socket 204A at a default articulation angle (e.g., 0° in the configuration shown in FIG. 3a, 3b), the straight segments 206A-I, 206A-II, 206B-I, 206B-II may contact each other. This may provide a robust and well-defined contact between the joint socket 204B and the joint head 204A.

[0064] The first and second elements 202A, 202B each include a first and second angled end surface 302A, 302B, respectively. The end surfaces 302A, 302B face each other and are configured to contact each other when the joint 204 reaches its maximum articulation angle, thereby preventing further articulation of the joint 204. The maximum articulation angle can correspond, for example, to the angle between the end surfaces 302A, 302B when the joint is at a default articulation angle, which may be, for example, between 5° and 75°, in some examples between 25° and 55°, and in one example between 35° and 45°.

[0065] The pipe elements 202A, 202B are annular elements that extend (e.g., surround or enclose) around the conduit opening 300 in a circumferential direction. In some examples, the pipe elements 202A, 202B may be identical elements, and the second element 202A may be rotated relative to the first element 202B by, for example, 90° along the circumferential direction. Each of the pipe elements 202A, 202B may include a pair of joint heads 204B on a first end face (e.g., on a proximal end face) and a pair of joint sockets 204A on a second end face (e.g., on a distal end face) opposite the first end face. The joint sockets 204A may be located on opposite sides of the pipe elements along the circumferential direction, and may be rotated relative to each other by, for example, 180° along the circumferential direction. The joint head 204B may also be positioned on opposite sides of the pipe element along the circumferential direction, e.g. such that the joint socket 204A and the joint head 204B are equidistantly spaced apart along the circumferential direction (e.g. 90° apart) as shown in Figures 3c to 3e, or may be rotated, e.g. 180° relative to each other along the circumferential direction.

[0066] Each of the tube elements 202A, 202B further includes four guide elements 304A, 304B, each of which is configured to guide a control wire for actuating the active bending portion 200-II of the tube 200. Each of the guide elements 304A, 304B is disposed on the outer periphery of the respective tube element 202A, 202B and includes a groove and a hole in which the respective control wire can be disposed. The first pair of guide elements 304A is disposed adjacent to a respective one of the joint sockets 204A and is aligned with the respective joint socket 204A along the circumferential direction, for example, as shown in Figures 3c to 3e. The second pair of guide elements is disposed adjacent to a respective one of the joint heads 204B and is aligned with the respective joint head 204B along the circumferential direction, for example, as shown in Figures 3c to 3e.

[0067] 4a and 4b show schematic diagrams of an active bending section 200-II of a tube for use in an endoscope according to one example of the present disclosure, where Fig. 4a shows a first side view of the active bending section 200-II and Fig. 4b shows a second side view of the active bending section 200-II, which may be perpendicular to the line of sight of Fig. 4a, for example.

[0068] The active bending section 200-II may be, or may form part of, the distal section 200-II of the tube 200, for example. The tube 200 is therefore used below as a non-limiting example for illustrative purposes. The active bending section 200-II connects the proximal section 200-I of the tube 200 to the tip of the tube 200 at the distal end 200B, which may be formed, for example, by the outermost distal element 402B of the active bending section 200-II. The active bending section 200-II may allow for active navigation of the tip of the tube 200, for example, using a control means, such as a control knob provided on the interface / control unit 102.

[0069] To this end, the active bending section 200-II includes a plurality of elements 202A, 202B, 402A, 402B, some or all of which (e.g., all of the elements 202A, 202B disposed between the outermost elements 402A, 402B) may be embodied similarly to the tube elements of Figures 3a to 3e, for example. The active bending section 200-II may include, for example, 3 to 50 elements, in some examples 5 to 20 elements, for example 8 elements in the examples of Figures 4a, 4b. The elements 202A, 202B are arranged in a chain, and (with the exception of the outermost elements 402A, 402B) the elements 202A, 202B are pivotally connected to their respective proximal elements by a pair of proximal joints 204 and to their respective distal elements by a pair of distal joints 204, with the joint 204 being formed by a joint socket 204A and a joint head 204B, as described in detail above with reference to Figures 2a to 2d and 3a to 3e.

[0070] In the example of Fig. 4a, 4b, the joints 204 are arranged in two articulation planes, with every other pair of joints along the chain (e.g., the first, third, fifth, ... pair of joints along the chain, visible in Fig. 4b and also referred to as the first set of joints) being arranged in a first articulation plane, and the remaining joints (e.g., the second, fourth, ... pair of joints along the chain, visible in Fig. 4a and also referred to as the second set of joints) being arranged in a second articulation plane perpendicular to the first articulation plane. In other words, on each element 202A, 202B, the pair of proximal joints 204 is displaced 90° along the circumferential direction relative to the pair of distal joints 204. Each set of joints is configured to allow articulation of the active curve 200-II in a direction or plane perpendicular to the respective articulation plane.

[0071] The guide elements 304A, 304B on the tube elements 202A, 202B are each aligned with one of the joints 204 as detailed above with reference to Figures 3c to 3e such that the control wires, when positioned within the guide elements 304A, 304B, extend in two wire planes aligned with the articulation planes, thereby enabling actuation of a set of joints associated with an articulation plane perpendicular to the wire plane in which the respective wires are positioned (and causing the active bending portion 200-II to bend in the wire plane in which the respective wire planes are positioned).

[0072] All of the tube elements 202A, 202B, except for the outermost elements 402A, 402B, may be identical elements with every other element rotated 90° along the circumference (such that the joint socket 204A is aligned with the joint head 204B on the adjacent element to form the joint 204). The outermost proximal element 402A may be configured to connect or attach to the proximal portion 200-I, and the outermost distal element 402B may form the distal tip of the tube 200 and may be configured to accommodate, for example, a camera and / or one or more medical tools. The outermost distal element 402B may also include one or more attachment points at which respective control wires may be attached to the outermost distal element 402B.

[0073] The outermost elements 402A, 402B further differ from the other elements 202A in that their end faces 406A, 406B are inclined at different angles relative to a plane perpendicular to the centerline 201 of the tube 200. In particular, the end faces 406A, 406B extend at a smaller angle relative to said plane than the end faces of the other elements 202A. Thus, the angle between each of the end faces 406A, 406B of the respective adjacent elements 202A, 202B and the opposite end face (and thus the maximum articulation angle of the outermost joint 404) is smaller than the angle between the opposing end faces of the elements 202A, 202B (and thus the maximum articulation angle of the joint 204). For example, the angle between the opposing end faces of the elements 202A, 202B may be between 35° and 45°, e.g., 40°. The angle between each end face 406A, 406B of the respective adjacent elements 202A, 202B and the opposite end face may be, for example, between 25° and 35°, for example, 30° in one example, or ⅔ of the angle between the opposing end faces of elements 202A, 202B. In another example, the angle between each end face 406A, 406B of the respective adjacent elements 202A, 202B and the opposite end face may be, for example, between 5° and 20°, for example, 15° in one example, or ⅓ of the angle between the opposing end faces of elements 202A, 202B.

[0074] FIG. 5a shows a schematic diagram of a pair of pipe elements 202A, 202B, each having a joint socket 204A and a joint head 204B, in a side view, according to another example of the present disclosure. The pipe elements 202A, 202B may be used, for example, in the pipe 200 of FIG. 1, which is used below as a non-limiting example for illustrative purposes. FIG. 5b and FIG. 5e show one of the pipe elements 202A, 202B in two different perspective views. In FIG. 5c and FIG. 5d, one of the pipe elements 202A, 202B is shown in a front view (e.g., along the longitudinal direction of the pipe 200 facing the proximal end 200A) and a back view (e.g., along the longitudinal direction of the pipe 200 facing the distal end 200B), respectively.

[0075] The pipe elements 202A, 202B are similar to the pipe elements of Figures 3a to 3e, in particular the pipe elements 202A, 202B are also annular elements including a pair of flat-topped triangular or V-shaped joint heads 204B on a first (e.g. proximal) end face and a pair of corresponding flat-topped triangular or V-shaped joint sockets 204A on a second (e.g. distal) end face, as shown for example in Figure 3b.

[0076] The pipe elements 202A, 202B differ from the pipe elements of Figures 3a to 3e in the arrangement of the guide elements 304 relative to the joint heads and sockets 204A, 204B. In the example of Figures 5a to 5e, the guide elements 304 are displaced relative to the joint heads and sockets 204A, 204B (displaced 45° along the circumferential direction from each of the joint heads 204B and the joint sockets 204A) such that each of the guide elements 304 is disposed between the respective joint heads 204B and the respective joints 204A, e.g. halfway between the joint heads 204 and the joint sockets 204A. This may allow, for example, to form a chain of pipe elements in which the articulation planes of the joints 204 and the wire planes of the control wires are not aligned, as described below with reference to Figures 6a, 6b.

[0077] The pipe elements 202A, 202B further include a lateral mechanical stop 500 configured to limit the movement of the joint head 204B relative to the respective joint socket 204A in a direction parallel to the articulation axis of the joint (e.g., radially). In the example of Fig. 5a to Fig. 5e, the lateral mechanical stop 500 is a sidewall of the joint socket 204A located on the inner circumference of the respective pipe element 202A, 202B. The sidewall may extend, for example, throughout the entire depth of the respective joint socket along the longitudinal direction, for example as shown in Fig. 5a. In some examples, the sidewall may include a tip portion, for example a circular tip portion, configured to engage a corresponding contact surface of the adjacent pipe element 204A / B.

[0078] 6a and 6b show schematic diagrams of an active bending section 200-II of a tube for use in an endoscope according to another example of the present disclosure, where Fig. 6a shows a first side view of the active bending section 200-II and Fig. 6b shows a second side view of the active bending section 200-II, which may be perpendicular to the line of sight of Fig. 6a, for example.

[0079] The active bending section 200-II is similar to the active bending section of Figures 4a, 4b and also includes a chain of pipe elements 202A, 202B, 402A, 402B pivotally connected to each other by a plurality of articulated joints 204, 404 formed by joint heads 204A and joint sockets 204B on the pipe elements 202A, 202B, 402A, 402B. With the exception of the outermost elements 402A, 402B, each of the elements 202A, 202B may be embodied, for example, similar to the pipe elements of Figures 5a to 5e. The elements 202A, 202B are arranged such that adjacent elements are rotated 90° relative to each other along the circumferential direction.

[0080] As in the example of Figures 4a, 4b, the joints 204 are arranged in two articulation planes. Every other pair of joints along the chain (e.g., pairs of joints 1, 3, 5, ..., also called the first set of joints) are arranged in a first articulation plane (inclined at +45° to the viewing direction of Figure 6a and -45° to the viewing direction of Figure 6b). The remaining joints (e.g., pairs of joints 2, 4, ..., also called the second set of joints) are arranged in a second articulation plane orthogonal to the first articulation plane (inclined at -45° to the viewing direction of Figure 6a and +45° to the viewing direction of Figure 6b). The joints of each set are configured to allow articulation of the active curve 200-II in a direction or plane perpendicular to the respective articulation plane.

[0081] As detailed above with reference to Figures 5a to 5e, the guide elements 304 on the tube elements 202A, 202B are circumferentially displaced by 45° from the adjacent joint sockets 204A and joint heads 204B (and thus adjacent joints) on the respective tube elements 202A / B. Thus, when the control wires are disposed within the guide elements 304, they extend in two wire planes inclined or rotated by 45° with respect to each of the articulation planes. For example, the first pair of guide elements 304 of each of the elements 202A, 202B are disposed in a first wire plane parallel to the viewing direction of Figure 6a, and the second pair of guide elements of each of the elements 202A, 202B are disposed in a second wire plane perpendicular to the viewing direction of Figure 6a (and thus parallel to the viewing direction of Figure 6b). When one or both control wires in a given wire plane are actuated (e.g., by pulling or releasing the respective control wires to adjust the longitudinal tension generated by the respective control wires via their attachment points on the outermost distal element 402B), both the first set of joints and the second set of joints are actuated simultaneously, causing the active bending portion 200-II to bend in the respective wire plane. Compared to an arrangement such as FIG. 4a, FIG. 4b, the articulation angle of each actuation joint at a given bending radius of the active bending portion 200-II may be approximately half as large.

[0082] The examples of the present disclosure disclosed herein merely constitute specific examples for illustrative purposes. The present invention can be implemented in various ways and with many modifications without changing the basic characteristics underlying it. Therefore, the present invention is defined only by the claims set forth below.

Claims

1. A tube (200) for use in an endoscope (100), the tube (200) comprising a plurality of elements (202, 402A, 402B) disposed along a centerline (201) of the tube (200) and pivotally connected to one another by a plurality of joints (204, 404) that allow the tube (200) to bend relative to a default configuration of the tube (200), each of the joints (204, 404) comprising: a joint head (204B) on each first element (202B, 402B) of said plurality of elements (202, 402A, 402B); a joint socket (204A) on each second element (202A, 402A) of the plurality of elements (202, 402A, 402B), the joint socket (204A) configured to receive the joint head (204B); Equipped with the joint socket (204A) and the joint head (204B) are rotated relative to the second element (202A, 402A) from a default articulation angle of the joint (204) associated with the default configuration to a target articulation angle. a first contact surface (206B) on the joint head (204B) is shaped to engage a second contact surface (206A) on the joint socket (204A) to push the joint head (204B) outwardly from the joint socket (204A) such that a displacement (D) of the joint head (204B) along the centerline (201) of the tube (200) relative to its position at the default articulation angle is greater than zero for any target articulation angle. Tube (200).

2. The first contact surface (206B) includes a protruding portion (208B) protruding from an inscribed circle (210B) of the first contact surface (206B), and the second contact surface (206A) includes a recessed portion (208A) recessed from the inscribed circle (210A) of the second contact surface (206A); the protruding portion (208B) of the first contact surface (206B) faces the recessed portion (208A) of the second contact surface (206A) when the first element (202B, 402B) is at the default articulation angle; When the first element (202B, 402B) is rotated from the default articulation angle to the target articulation angle, the protruding portion (208B) engages with the second contact surface (206A) to push the joint head (204B) outwardly from the joint socket (204A). The tube (200) of claim 1.

3. 3. The pipe (200) of claim 1 or 2, wherein the first contact surface (206B) comprises a first straight portion (206B-I) and a second straight portion (206B-II) extending at an angle relative to the first straight portion (206B-I), the first and second straight portions (206B-I, 206B-II) being positioned such that the first and second straight portions (206B-I, 206B-II) each contact a respective straight portion (206A-I, 206A-II) of the second contact surface (206A) when the first element (202B, 402B) is at the default articulation angle.

4. 4. The pipe (200) of claims 2 and 3, wherein the first and second straight portions (206B-I, 206B-II) of the first contact surface (206B) are tangent to the inscribed circle (210B) of the first contact surface (206B), and the protruding portion (208B) of the first contact surface (206B) is disposed between the first and second straight portions (206B-I, 206B-II).

5. 5. The tube (200) of claim 1, wherein the joint socket (204A) and the joint head (204B) are shaped such that when the first element (202B, 402B) is rotated from the default articulation angle to a target articulation angle that differs from the default articulation angle by more than 10°, preferably by more than 20°, the displacement of the joint head (204B) along the center line (201) of the tube (200) relative to its position at the default articulation angle increases monotonically.

6. 6. The pipe (200) of claim 1, wherein the joint socket (204A) and the joint head (204B) are shaped such that a tip of the joint head (204B) is separated from the joint socket (204A) by a gap (214) when the first element (202B, 402B) is at the default articulation angle.

7. 7. The pipe (200) of claim 1, wherein the joint socket (204A) is configured such that the joint head (204B) can be removed from the joint socket (204A) along the centerline (201) of the pipe (200).

8. 8. The pipe (200) of claim 1, wherein the joint socket (204A) and / or the joint head (204B) are provided with a lateral mechanical stop (500) configured to limit movement of the joint head (204B) relative to the joint socket (204A) in a direction parallel to an articulation axis of the joint (204, 404).

9. 9. The pipe (200) of claim 1, wherein one or more joints (204, 404) of the plurality of joints (204, 404) have a maximum articulation angle that is different from a maximum articulation angle of another joint (204, 404) of the plurality of joints (204, 404).

10. 10. The pipe (200) of claim 9, wherein the elements (202, 402A, 402B) are arranged in a chain, and an outermost joint (404) at one or both ends of the chain has a smaller maximum articulation angle than other joints (204) of the chain.

11. 11. The pipe (200) of claim 10, wherein the maximum articulation angle of the outermost joints (404) at one or both ends of the chain is between 10% and 70% of the maximum articulation angle of other joints (204) in the chain.

12. for each of said joints (204, 404), said first element (202B, 402B) comprises a first inclined end surface (302B) and said second element (202A, 402A) comprises a second inclined end surface (302A) facing said first inclined end surface (302B), said first and second end surfaces (302B, 302A) being configured to contact each other when said joint (204, 404) reaches its maximum articulation angle to prevent further articulation of said joint (204, 404); an angle between the first and second end faces (302B, 302A) associated with the outermost joint (404) at one or both ends of the chain is less than an angle between the first and second end faces (302B, 302A) associated with other joints (204) in the chain when the respective joints (204, 404) are at the default articulation angle; 12. A tube (200) according to claim 10 or 11.

13. 13. The tube (200) of any one of claims 1 to 12, wherein some or all of the elements (202, 402A, 402B) comprise guide elements (304, 304A, 304B) configured to guide control wires for actuating the plurality of joints (204, 404).

14. The tube (200) of claim 13, wherein the guide elements (304, 304A, 304B) are disposed on an outer periphery of the respective elements (202, 402A, 402B).

15. 15. The tube (200) of claim 13 or 14, wherein the guide elements (304A, 304B) are configured to guide the control wires such that the control wires are positioned adjacent to an inner or outer side of a joint head (206B) on the respective element (202B) or on an adjacent element (202B).

16. At least some of the elements (202A, 202B) each include said tube (200) being pivotally connected to respective first adjacent elements (202B, 202A) by respective first pair of joints (204) arranged on either side thereof and to respective second adjacent elements (202B, 202A) by respective second pair of joints (204) arranged on either side thereof, said first and second pair of joints (204) being displaced by 75° to 105° relative to each other along a circumferential direction (φ) of said tube (200); four guide elements (304) arranged along the circumference of each of the elements (202A, 202B), each of the four guide elements (304) being displaced from an adjacent joint (204) by 35° to 55° along the circumferential direction (φ) of the tube (200); A tube (200) according to any one of claims 13 to 15.

17. 17. The pipe (200) of any one of claims 1 to 16, wherein each of the elements (202, 402A, 402B) extends around a respective conduit opening (300), the diameter of the conduit opening (300) varying by less than 25%, preferably less than 15%, along the circumference of the respective element (202, 402A, 402B).

18. The tube (200, 700) of any one of claims 1 to 17, wherein the tube (200) is an insertion tube or a hypotube for use in the endoscope (100).

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