Bendable tube for use with endoscopes

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] FIELD OF THE DISCLOSURE 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 can 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 an incision or bodily opening. The endoscope can include an interface / control unit and an insertion tube coupled to the interface / control unit. The insertion tube is configured to be inserted into the patient's body and can include one or more conduits for providing access to the tissue within the body. The one or more conduits can be configured, for example, to receive medical tools and / or fluids and to guide the medical tools and fluids, respectively, to the tissue of interest.

[0003] The insertion tube may be bendable to facilitate insertion into a patient's body. To this end, the insertion tube may include, for example, one or more passively and / or actively bendable portions (also referred to as passive and active bending sections, respectively). Passively bendable portions may be formed, for example, of a bendable or flexible material or structure that can be deformed by applying an external force. Actively bendable portions may include multiple articulatable joints, for example, for actively navigating the tip of an endoscope at the distal end of the insertion tube. Each of the joints may include, for example, a circular joint head disposed within a circular joint socket such that the joint head can rotate relative to the joint socket, thereby allowing the insertion tube to bend. Tubes with actively bendable portions are known, for example, from WO 2018 / 029917 A1 and U.S. Patent Publication No. 2015 / 0164305 A1.

[0004] However, such actively bendable sections can be mechanically unstable because the joints may have a tendency to align in a zigzag pattern, tilting adjacent joints in opposite directions. This can lead to reduced stability against side loads and can also reduce the effective internal cross-sectional area of ​​the insertion tube. The need to place means for controlling the joints, such as control wires, can further reduce the available space within the tube. Furthermore, clearance between the joint head and socket may be required to prevent the joint from jamming. This can reduce the efficiency of torque transmission along the tube, as the clearance may first need to be compensated for before torque is 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 with an endoscope. The tube includes (i.e., includes, but is not limited to) a plurality of elements disposed along a centerline of the 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 being configured to receive the joint head. The joint socket and joint head are shaped such that, when the first element is rotated 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 outward from the joint socket such that the displacement of the joint head along the 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 its proximal end to its distal end. As used herein, the term "proximal" may refer to elements, features, or locations along the length of the tube that are closer to a physician or other medical professional during use of the endoscope (i.e., closer to the endoscope's interface / controls), and the term "distal" may refer to elements, features, or locations along the length of the tube that are examined or treated within a patient's body during use of the endoscope (e.g., farther from the endoscope's interface / controls). A direction along the centerline of the tube (e.g., from the proximal end to the distal end) may hereinafter also 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 also 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 also 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 the 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 longitudinally, for example, in a chain as described in more detail 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 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 the pipe may be positioned 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 located within the tube. The centerline may be, for example, a line or path connecting the centers of the outer or inner circumferences (e.g., center of gravity) of the tube 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 one another by multiple joints such that adjacent elements can be pivoted (e.g., tilted or rotated) relative to one another. This allows the tube to be bent (or otherwise deformed) relative to its default configuration. The default configuration can be, for example, a configuration or state that the tube ideally assumes when a uniform tension or force is applied along the length of the tube, e.g., between the proximal and distal ends of the tube (e.g., without a bias in a particular direction). In some examples, the default configuration can be a configuration or state that the tube ideally assumes when no external tension or force is applied to the tube (e.g., when a means for actuating a joint, such as a control wire, is not actuated). The default configuration can be associated with a predetermined bending radius that the tube, or a portion thereof, assumes when the tube is in the default configuration. The default configuration can particularly be a straight configuration (corresponding to an infinite bending radius), i.e., the tube can 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 within a joint socket on the respective second element. The joint head may, for example, be a protrusion or projection on the first element, which may extend, for example, in the longitudinal direction. The joint socket may, for example, be a corresponding notch or recess on the second element, into which the joint head, or a portion thereof, may be disposed. The joint socket and the joint head each include first and second contact surfaces 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 instances 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 tilted 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, as 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 toward a default configuration, such that the tube preferably assumes the default configuration when 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 each target articulation angle. The 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 cases between 0.5 μm and 50 μm, and in one case 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 cases between 5 μm and 0.5 mm, in one case between 20 μm and 0.2 mm, and in one case 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), with the joint head including a protruding portion relative to the circular shape and the joint socket including a recessed portion relative to the 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] As used herein, the inscribed circle of a contact surface may be, for example, a circle to which at least two non-adjacent portions of the respective contact surface (e.g., opposite portions of the joint head and socket) are tangent. The inscribed circle may lie 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, the at least two non-adjacent portions may be portions of the respective contact surface 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 the portions of the respective contact surface, particularly the centers of the portions of the respective contact surface. In one example, the inscribed circle may be the largest circle to which the at least two non-adjacent portions of the respective contact surface are tangent, the two non-adjacent portions that 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 each contact surface 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, allowing the joint head to be positioned further within 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 outward from the joint socket. For example, the protruding portion may contact the second contact surface (e.g., a non-recessed portion thereof), thereby further urging the joint head from the joint socket. The non-circular shapes of the joint head and joint socket can prevent pivoting or rotation of the joint about a fixed articulation axis and, as described above, may additionally induce translation of the joint head relative to the joint socket.

[0022] In some examples, the first contact surface may include a first linear portion and a second linear portion extending 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 having one or both principal curvatures equal to zero (i.e., a portion exhibiting 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 joint socket may have a triangular or V-shape or cross-section having a pair of linear edges or surfaces extending at an angle relative to each other (e.g., when viewed along the joint's articulation axis and / or radially). 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 joint socket may have a flat-topped triangular or V-shape or cross-section with flat or rounded tips. The flat or rounded tips may form the protruding and recessed portions of the corresponding contact surfaces, 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 10° or more, in some examples by 20° or more, and in one example by 30° or more, the displacement of the joint head along the centerline of the tube relative to its position at the default articulation angle increases monotonically, in one example strictly monotonically. For example, the displacement may 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°, and in one example by 30° to 50°. Additionally or alternatively, the displacement of the joint head may increase monotonically, in one example strictly monotonically, as the first element increases from the default articulation angle to the 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 joint head are shaped such that a tip of the joint head is separated from the joint socket by a gap when the first element is at the default articulation angle. For example, the protruding portion of the first contact surface and the recessed portion of the second contact surface may be shaped such that the protruding portion is separated from the joint socket by a gap when the first element is at the default articulation angle. 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 in the joint socket may be greater than the maximum width of the joint head (e.g., along the circumferential direction) so that the joint head can freely enter and exit the joint socket through said opening. Such an open joint configuration, in which the joint head is not confined to 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 the application of excessive force), the joint head may be held within the joint socket by a means for actuating the joint, such as a control wire, which may be configured to apply a uniform compressive tension, e.g., longitudinally, when not actuated.

[0027] In some examples, the joint socket and / or 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 include one or more lateral sidewalls of the joint socket (e.g., an inner lateral sidewall and / or an outer trailing sidewall of the joint socket), which may be, for example, disposed on the inner and / or outer periphery of the respective element. The one or more lateral sidewalls 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, the 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 with 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 include, for example, 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 the maximum articulation angle of any given joint is greater than the maximum articulation angle of, for example, the proximally (or distally) adjacent joint. Different maximum articulation angles may be achieved, for example, by providing beveled 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 pipe elements are arranged in a chain, e.g., in a serial configuration in which each pipe element (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 joint, 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 each other 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 angled 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 face, e.g., a contact feature on the other end face, 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 smaller than the angle between the first and second end faces associated with the other joints in the chain when the respective joints are at a default articulation angle. The angle between the first and second angled 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 can also include a control wire, which can be disposed within the guide element of the tube element. The control wire can be configured, for example, when actuated, to apply a compressive tension to the tube or a portion thereof, particularly the portion including the tube element, e.g., along its length from the distal end to the proximal end. The control wire can be connected or attached to a distal attachment point, which can be disposed distally of the tube element, e.g., at or adjacent the distal end or tip of the tube. Pulling the proximal end of the control wire can generate a force from the distal attachment point toward the proximal end of the tube. In some examples, the control wire can 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 within the joint socket.

[0034] The guide elements can 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 can 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 can, 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 positioned 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 the joint head or joint socket on the respective element along a circumferential direction when positioned within the guide element such that the control wire extends, for example, adjacent to the respective joint, for example through or adjacent to the actuation axis of the joint. A control wire positioned adjacent to an inner or outer side of the 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 opposite sides of the tube. The first pair of joints may be displaced relative to each other along the circumferential direction by, for example, 150° to 210°, in one example, 170° to 190°. 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 the 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 opposite sides of the tube. The second pair of joints may be displaced relative to each other along the circumferential direction by, for example, 150° to 210°, in one example, 170° to 190°. 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 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 pipe by 75° to 105°, in some cases 80° to 100°, and in one case 85° to 95° (e.g., 90°). In other words, on each corresponding pipe 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 their 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 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°, and 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°, and in some instances, 40° to 50° (e.g., 45°), relative 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 a tube to bend in the respective wire plane.

[0040] In other examples, each of the four guide elements can be circumferentially aligned with a corresponding joint, e.g., such that the wire plane is aligned with the articulation direction / plane, in which case actuation of each of the control wires can actuate only 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, such that, for example, the sidewall of each pipe element circumferentially encloses or surrounds the respective conduit opening. 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%, and in one instance 10% to 25%) along the circumference of each element, preferably by less than 15%, and in one instance by less than 10%. 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 of the conduit openings to the average diameter of the conduit opening. The pipe elements may have smooth inner surfaces along their inner circumferences. 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 instances 20% or more (e.g., 20% to 100%), in one instance 30% or more (e.g., 30% to 100%), and in one instance 40% or more (e.g., 40% to 100%) of the average radius of the conduit opening.

[0042] Tubes according to the present disclosure are configured for use with 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 portion thereof, particularly a hypotube, of the endoscope. The endoscope may further include an interface / control unit configured to be coupled to the tube.

[0045] A detailed description of the present disclosure and examples thereof follows with reference to the drawings, which show the following schematic diagrams: [Brief explanation 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] 3b shows an enlarged view of the joint head and joint socket of the pipe element of FIG. 3a; FIG. [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. 10 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] 5b is another perspective view of one of the pipe elements of FIG. 5a. FIG. [Figure 6a] FIG. 10 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 INVENTION

[0047] 1 shows 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 unit 102, and the tube 200 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, with the proximal end 200A adjacent to the interface / control unit 102 (e.g., connected or attached thereto via the connector 104) and the distal end 200B facing away from the interface / control unit 102. The direction X along the centerline 201 from the proximal end 200A to the distal end 200B may be referred to hereinafter as the longitudinal direction, axial direction, or X direction. The 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 be referred to hereinafter as the circumferential direction, azimuthal direction, or φ direction.

[0049] The one or more ports 106 may include one or more fluid ports that are in fluid communication with, for example, the interior of the tube 200, for example, a conduit (not shown) formed by or disposed within the tube 200, for example, 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, for example, 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, for example, within 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 at or connected to the distal end 200B of the tube 200, for example, 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, e.g., 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, e.g., 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 section and an interface section, where the control section may be connected to the proximal end 200A of the tube 200, e.g., via a connector 104, and the interface section may be connected to the control section, e.g., via a flexible tube or supply tube.

[0051] 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 , tube 200 includes first or proximal portion 200-I and second or distal portion 200-II. Proximal portion 200-I may be or include, for example, one or more passive bending portions (not shown) configured to bend or deform upon application of an external force. The passive bending portions may be made of (e.g., 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 the wall of tube 200 to increase the flexibility of tube 200 within the respective bendable portion. In some examples, proximal portion 200-I may also include a rigid portion (not shown) in addition to or instead of one or more passive bending portions, for example, at proximal end 200A adjacent connector 104. The length and diameter of the tube 200 can be selected to suit the type of endoscope with which the tube 200 will be used. The tube 200 can have a length of, for example, 20 cm to 200 cm, and in some instances, 50 cm to 150 cm. The outer diameter of the tube 200 can be, for example, between 1 mm and 20 mm, and in some instances, between 2 mm and 10 mm.

[0052] In the example of FIG. 1 , distal section 200-II is or includes a bending section, particularly an active bending section, and therefore may also be referred to as active bending section 200-II. Active bending section 200-II includes multiple elements 202 (hereinafter also referred to as tube elements 202) arranged along a centerline 201 of tube 200. The tube elements 202 are pivotally connected to one another by multiple joints 204 to enable bending of tube 200, particularly active bending section 200-II, relative to a default configuration of tube 200. The default configuration may be, for example, a straight configuration as shown in FIG. 1 , in which tube 200 is not bent and centerline 201 is straight. The default configuration may be, for example, a configuration that 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 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 joint 204 are rotated relative to one another from the default articulation angle of the joint 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 joint 204 extends or lengthens longitudinally to slightly increase the length of the tube 200 along the longitudinal direction, as described in more detail below with reference to FIGS. 2a-2d , for example. Each of the joints 204 may be embodied similarly to the joints of FIGS. 2a-2d , 3a , 3b , and 5a . In the default configuration, the tube 200 (e.g., its centerline 201) may have its smallest longitudinal extent, i.e., its smallest longitudinal length. When a uniform tension is applied longitudinally, the tube 200 may tend to decrease or minimize its length and may assume the default configuration, i.e., straighten in the example of FIG. 1 .

[0054] 2a-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 one another, 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 FIGS. 2a-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 each first element 202B (e.g., the distal element of the joint 204 closer to the distal end 200B of the tube 200) and a joint socket 204A on each second element 202A (e.g., the 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 FIGS. 2a-2d. In FIG. 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 FIGS. 2b-2d, the joint 204 is shown with the joint head 204B disposed within the joint socket 204A. In Figure 2b, 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, joint 204 is at first and second target articulation angles, respectively, that differ from the default articulation angle, e.g., 10° in the example of Figure 2c and 20° in the example of Figure 2d. Thus, centerline 201 is curved or twisted in Figures 2c and 2d.

[0056] The joint head 204B includes a first contact surface 206B configured to slidably engage a second contact surface 206A on the joint socket 204A when the joint head 204B is received within the joint socket 204B. The joint socket 204A and the joint head 204B, and particularly 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 urge the joint head 204B outward from the joint socket 204A. This displaces the joint head 204B by a displacement D relative to its position at the default articulation angle of FIG. 2b such that the joint 204 is slightly extended or lengthened 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-2d, both the joint socket 204A and the joint head 204B have non-circular cross-sections 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. 2a-2d, the inscribed circles 210A, 210B are defined such that they are perpendicular to the articulation axis of the joint 204, and the portion of each contact surface 208A, 208B that contacts the other contact surface 208B, 208A at the default articulation angle is tangent to the inscribed circle 210A, 210B, as shown in FIG. 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 be, for example, 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 the recessed portion 208A 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 forces the joint head 204B 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, for example, be 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 that is 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 range of motion of the joint 204 (e.g., up to the 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 portion of the centerline 201, according to 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 may be in a different position at each articulation angle. The articulation axis may not tilt and may always remain parallel to its orientation, e.g., the radial direction, at a default angle (i.e., it may be shifted or translated by a parallel offset).

[0060] FIG. 3a shows a schematic side view of a pair of pipe elements 202A, 202B, each having a joint socket 204A and a joint head 204B, according to one 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 joint head 204B corresponding to the dotted rectangle in FIG. 3a. In FIGS. 3c and 3d, one of the pipe elements 202A, 202B is shown in a front view (e.g., along the length of the pipe 200 facing the proximal end 200A) and a rear view (e.g., along the length 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-2d, the joint head 204B includes a first contact surface 206B having a protruding portion 208B that protrudes 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 the first contact surface 206A to enable articulation of the joint 204. The second contact surface 206A includes a recessed portion 208A that is recessed from the inscribed circle 210A of the second contact surface 206A.

[0063] In the example of FIGS. 3a and 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 outline in a plane perpendicular to the articulation axis of the joint 204). The first contact surface 206B includes a pair of linear portions 206B-I and 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 linear portions 206A-I and 206A-II located on either side of the recessed portion 208A. Each of the linear portions 206A-I, 206A-II, 206B-I, and 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 linear segments 206A-I, 206A-II, 206B-I, and 206B-II, as shown in Figure 3b, for example. 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 Figures 3a and 3b), the linear segments 206A-I, 206A-II, 206B-I, and 206B-II may contact one another, thereby providing 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 may 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) circumferentially around the conduit opening 300. In some examples, the pipe elements 202A, 202B may be identical elements, with the second element 202A rotated relative to the first element 202B by, for example, 90° along the circumference. 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 opposite the first end face (e.g., on a distal end face). The joint sockets 204A may be located on opposite sides of the pipe element along the circumference, for example, rotated 180° relative to each other along the circumference. The joint head 204B may also be positioned on opposite sides of the pipe element along the circumferential direction, for example so 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 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 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 through 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 FIGS. 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 FIGS. 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] Active bending section 200-II may be, or may form part of, distal section 200-II of tube 200, for example. Accordingly, tube 200 is used below as a non-limiting example for illustrative purposes. Active bending section 200-II connects proximal section 200-I of tube 200 to the tip of tube 200 at distal end 200B, which may be formed, for example, by outermost distal element 402B of active bending section 200-II. Active bending section 200-II may allow the tip of tube 200 to be actively navigated using a control means, such as a control knob provided on interface / control unit 102.

[0069] To this end, the active bending section 200-II includes multiple 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-3e. The active bending section 200-II may include, for example, 3 to 50 elements, and in some examples, 5 to 20 elements, such as 8 elements in the examples of Figures 4a and 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 each proximal element by a pair of proximal joints 204 and to each distal element by a pair of distal joints 204, with the joints 204 being formed by joint sockets 204A and joint heads 204B, as detailed above with reference to Figures 2a to 2d and 3a to 3e.

[0070] In the example of FIGS. 4a and 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, ... pairs of joints along the chain, visible in FIG. 4b and also referred to as the first set of joints) arranged in a first articulation plane, and the remaining joints (e.g., the second, fourth, ... pairs of joints along the chain, visible in FIG. 4a and also referred to as the second set of joints) arranged in a second articulation plane that is perpendicular to the first articulation plane. In other words, on each element 202A, 202B, the proximal pair of joints 204 is circumferentially displaced 90° relative to the distal pair of joints 204. Each set of joints is configured to allow articulation of the active curved section 200-II in a direction or plane perpendicular to its 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 so 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 the set of joints associated with the articulation plane perpendicular to the wire plane in which the respective wires are positioned (and causing the active bending section 200-II to bend within the wire plane in which the respective wire planes are positioned).

[0072] With the exception of the outermost elements 402A, 402B, all of the tube elements 202A, 202B may be identical elements with every other element rotated 90° circumferentially (so 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 house, for example, a camera and / or one or more medical tools. The outermost distal element 402B may also include one or more attachment points to which respective control wires can 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 pipe 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 each adjacent element 202A, 202B and the opposite end face may be, for example, between 25° and 35°, for example, 30° in one example, or two-thirds of the angle between the opposing end faces of elements 202A, 202B. In another example, the angle between each end face 406A, 406B of each adjacent element 202A, 202B and the opposite end face may be between 5° and 20°, for example, 15° in one example, or one-third of the angle between the opposing end faces of elements 202A, 202B.

[0074] Figure 5a shows a schematic side view of a pair of pipe elements 202A, 202B, each having a joint socket 204A and a joint head 204B, according to another example of the present disclosure. The pipe elements 202A, 202B may be used, for example, in the pipe 200 of Figure 1, which is used below as a non-limiting example for illustrative purposes. Figures 5b and 5e show one of the pipe elements 202A, 202B in two different perspective views. In Figures 5c and 5d, one of the pipe elements 202A, 202B is shown in a front view (e.g., along the length of the pipe 200 facing the proximal end 200A) and a back view (e.g., along the length 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, and in particular are annular elements that also include 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° circumferentially from each of the joint heads 204B and joint sockets 204A) so that each guide element 304 is positioned between the respective joint head 204B and the respective joint 204A, e.g., midway between the joint head 204 and the joint socket 204A. This may, for example, allow for the formation of chains of pipe elements in which the articulation planes of the joints 204 and the wire planes of the control wires are not aligned, as will be described below with reference to Figures 6a and 6b.

[0077] The pipe elements 202A, 202B further include lateral mechanical stops 500 configured to limit movement of the joint head 204B relative to the respective joint socket 204A in a direction parallel to the joint articulation axis (e.g., radially). In the example of Figures 5a-5e, the lateral mechanical stops 500 are side walls of the joint socket 204A disposed on the inner periphery of each pipe element 202A, 202B. The side walls may extend, for example, throughout the entire depth of the respective joint socket along the longitudinal direction, as shown, for example, in Figure 5a. In some examples, the side walls may include tip portions, e.g., rounded tip portions, configured to engage corresponding contact surfaces of adjacent pipe elements 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 unit 200-II is similar to the active bending unit of Figures 4a and 4b and also includes a chain of pipe elements 202A, 202B, 402A, 402B pivotally connected to one another 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 similarly to the pipe elements of Figures 5a to 5e, for example. The elements 202A, 202B are arranged such that adjacent elements are rotated 90° relative to one another along the circumferential direction.

[0080] As shown in the example of Figures 4a and 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 referred to as the first set of joints) are arranged in a first articulation plane (inclined at +45° relative to the viewing direction in Figure 6a and -45° relative to the viewing direction in Figure 6b). The remaining joints (e.g., pairs of joints 2, 4, ..., also referred to as the second set of joints) are arranged in a second articulation plane orthogonal to the first articulation plane (inclined at -45° relative to the viewing direction in Figure 6a and +45° relative to the viewing direction in Figure 6b). The joints in each set are configured to allow articulation of the active bending section 200-II in a direction or plane perpendicular to the respective articulation plane.

[0081] As detailed above with reference to Figures 5a-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 the 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 that are inclined or rotated by 45° relative to each of the articulation planes. For example, the first pair of guide elements 304 on each of elements 202A, 202B are disposed in a first wire plane that is parallel to the viewing direction of Figure 6a, and the second pair of guide elements on each of elements 202A, 202B are disposed in a second wire plane that is 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 section 200-II to bend in the respective wire plane. Compared to the arrangement shown in Figures 4a and 4b, the articulation angle of each actuation joint at a given bending radius of the active bending section 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 embodied in various ways and with many modifications without altering its basic underlying characteristics. Accordingly, the present invention is defined solely by the claims that follow.

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), the joints (202, 404) enabling 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 the 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 head (204B) has a convex shape as a whole, The joint socket (204A) has an overall concave shape, 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) outward from the joint socket (204A) so 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) has a protruding portion (208B) protruding from an inscribed circle (210B) of the first contact surface (206B), and the second contact surface (206A) has 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) outward from the joint socket (204A). The tube (200) of claim 1.

3. 2. The pipe of claim 1, wherein the first contact surface comprises a first linear portion and a second linear portion extending at an angle relative to the first linear portion, the first and second linear portions being positioned such that the first and second linear portions are in contact with respective linear portions of the second contact surface when the first element is at the default articulation angle.

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

5. 2. The pipe (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 10° or more, the displacement of the joint head (204B) along the center line (201) of the pipe (200) relative to its position at the default articulation angle increases monotonically.

6. 2. The pipe (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 20° or more, the displacement of the joint head (204B) along the center line (201) of the pipe (200) relative to its position at the default articulation angle monotonically increases.

7. 2. 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.

8. 2. 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).

9. 2. The pipe (200) of claim 1, wherein the joint socket (204A) or the joint head (204B) comprises 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 the articulation axis of the joint (204, 404).

10. 2. 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).

11. 11. The pipe (200) of claim 10, 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.

12. 12. The pipe (200) of claim 11, wherein the maximum articulation angle of the outermost joint (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.

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

14. 2. The tube (200) of claim 1, 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).

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

16. 15. The tube (200) of claim 14, wherein the guide elements (304A, 304B) are configured to guide the control wires so 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).

17. At least some of the elements (202A, 202B) each comprise: the tube (200) is pivotally connected to each first adjacent element (202B, 202A) by respective first pairs of joints (204) arranged on both sides thereof, and to each second adjacent element (202B, 202A) by respective second pairs of joints (204) arranged on both sides thereof, the first and second pairs of joints (204) being displaced by 75° to 105° relative to each other along the circumferential direction (φ) of the 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 by 35° to 55° from an adjacent joint (204) along the circumferential direction (φ) of the pipe (200); 15. The tube (200) of claim 14.

18. 18. The pipe (200) of claim 17, 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% along the circumference of the respective element (202, 402A, 402B).

19. 18. The pipe (200) of claim 17, 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 15% along the circumference of the respective element (202, 402A, 402B).

20. The tube (200) of any one of claims 1 to 19, wherein the tube (200) is an insertion tube or hypotube for use in the endoscope (100).

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