Patent Description:
Endoscopes have attained great acceptance within the medical community, since they provide a means to perform procedures with minimal patient trauma, while enabling the physician to view the internal anatomy of the patient. Over the years, numerous endoscopes have been developed and categorized according to specific applications, such as cystoscopy, colonoscopy, laparoscopy, upper GI endoscopy and others. Endoscopes may be inserted into the body's natural orifices or through an incision in the skin.

An endoscope is usually an elongated tubular shaft, rigid or flexible, having one or more video cameras or fiber optic lens assemblies at its distal end. The shaft is connected to a handle, which sometimes includes an ocular for direct viewing. Viewing is also usually possible via an external screen. Various surgical tools may be inserted through a working channel in the endoscope to perform different surgical procedures.

Endoscopes may have a front camera and a side camera to view the internal organ, such as the colon, illuminators for each camera, one or more fluid injectors to clean the camera lens(es) and sometimes also the illuminator(s) and a working channel to insert surgical tools, for example, to remove polyps found in the colon. Often, endoscopes also have fluid injectors ("jet") to clean a body cavity, such as the colon, into which they are inserted. The illuminators commonly used are fiber optics which transmit light, generated remotely, to the endoscope tip section. The use of light-emitting diodes (LEDs) for illumination is also known.

The elongated tubular shaft, also known as the insertion portion of the endoscope has a bending section, proximal to a distal end of the shaft that can bend upon application of an external control to navigate a curved path inside a body cavity, or to access difficult areas within the cavity. However, sometimes it is desirable to vary the degree of bending, based on the application or based on the region inside the body cavity where a distal end of the shaft is navigating. A stiffer insertion portion may reduce the chances of looping of the tubular shaft inside the body cavity, whereas a softer insertion portion may make it easier to reach the cecum. Lack of the ability to vary the stiffness of the insertion portion, such as around the bending portion, could result in patient discomfort and/or increased time for endoscopic examinations. Additionally, some physicians may prefer using a stiffer insertion portion, while some others may prefer a flexible insertion portion. Moreover, repeated reprocessing of parts of endoscope, including its cleaning, may influence the flexible characteristics of the insertion portion. As a result, the insertion portion may become more flexible than required with each time it is cleaned.

<CIT>, assigned to Storz, discloses "a flexible endoscope comprising: a flexible shaft portion having a distal and a proximal end and including an outer layer comprising an electrically insulated water-tight material, an inner layer enclosed by said outer layer, a plurality of elongated segments disposed in said outer layer and comprising a polymer material that changes characteristics upon the application of an electrical current, a handle portion coupled to said flexible shaft portion, an electrical source for providing the electrical current to said at least one elongated segment, and electrical conductors electrically connected between said plurality of elongated segments and said electrical source, said electrical conductors extending from said flexible shaft portion through said handle portion to said electrical source, wherein said plurality of elongated segments are positioned in said outer layer in an end-to-end fashion along a longitudinal length of said flexible shaft portion and each elongated segment has at least one end affixed to said inner layer such that upon an application of electrical current to said plurality of elongated segments, said plurality of elongated segments change physical dimension, and wherein said inner layer moves relative to said outer layer based on the dimensional change of at least one of said plurality of elongated segments. " However, the '<NUM> patent does not provide a complete mechanical control of the flexibility of the insertion portion.

<CIT>, which document is considered to represent the most relevant prior art and discloses the features of the preamble of claim <NUM>, describes a hardness adjusting device which includes a closed coil spring arranged in a soft part of an endoscope to adjust the flexibility of the soft part of an endoscope insertion part. A wire is provided to be inserted through the closed coil spring. A traction mechanism applies compressive force to the closed coil spring by relatively pulling the wire and the closed coil spring. An elastic member is arranged in series with at least one of the closed coil spring and the wire in a region between the tip and base end of the wire.

<CIT> discloses a method and apparatus for spatially orienting a remote flexible member such as the tip of a borescope to point in a desired direction. The method employs heating to its transition temperature a shape memory effect SME alloy actuating element coupled to the tip and cable. In one embodiment, an elongated helical spring fabricated from an SME alloy such as NI--TI or CU--ZN--AL is longitudinally disposed between the remote end of a borescope cable, and the borescope tip. An electrical resistance wire heater in contact with the spring and energized by an electrical power source controlled by an observer at the near end of the cable is used to heat a selected part of the spring to the transition temperature of the SME alloy of which it is fabricated, producing a controlled deflection of the borescope tip to point in a direction directed by the observer.

<CIT> describes a steerable catheter comprised of an elongated catheter body containing one or more lumens. A catheter tip is fixedly secured to the distal end of the catheter body and a steerable catheter handle is attached to the proximal end of the catheter body. Said steerable catheter handle is comprised of a mounting shaft containing a geared slide, a slide block, a slide block adjustment screw, and an adjustment screw guide; an adjustment knob comprised of a geared inset and an external rotation element for rotating the adjustment knob, a handle grip which fits over the mounting shaft and electrical connectors for attachment to the proximal end of the mounting shaft and which contain electrode electrical wires.

Thus, what is needed is an insertion portion with an ability to vary its stiffness or flexibility, with minor modifications to the existing structure, shape, size, and manufacturing complexity. Additionally, what is needed is a flexible shaft with an insertion portion that may utilize material available with an endoscope system.

The following embodiments and aspects thereof are described and illustrated in conjunction with systems, tools and methods, which are meant to be exemplary and illustrative, not limiting in scope.

The present specification discloses various endoscope assemblies comprising an element of variable stiffness embedded within an insertion portion of the endoscope assembly and a controller to vary stiffness of the element.

The present specification discloses an endoscope assembly comprising an insertion portion that is connected to a handle at a proximal end of the insertion portion and a bending portion at a distal end of the insertion portion, comprising: a screw configured to rotate around a longitudinal axis of the endoscope assembly; a housing in physical communication with the screw, wherein the housing is configured to move in a direction that is at least one of a distal direction and a proximal direction along the longitudinal axis of the endoscope assembly, with the rotation of the screw; a stopper placed within the housing; and a wire having a proximal end and a distal end, wherein the proximal end of the wire is connected to the stopper, the wire stretches along a length of the insertion portion, and the distal end of the wire is connected to a proximal end of the bending portion and wherein the wire stiffens the insertion portion upon rotation of the screw towards distal end of the insertion portion.

Optionally, the wire is placed inside a coil fixed to an internal periphery of the insertion portion.

Optionally, the endoscope assembly further comprises a housing containing at least one of the screw, the internal housing, the stopper, and the wire.

Optionally, the endoscope assembly further comprises a knob located in the handle and in physical communication with the screw, wherein a rotation of the knob causes a rotation of the screw.

The stopper may be configured within said housing such that a proximal movement of the housing causes said stopper to move proximally and such that a distal movement of the housing causes the stopper to move distally.

Movement of the wire may cause at least one of the pitch, degree of expansion, degree of compression, and flexibility of the coil to change.

Movement of the wire may cause at least one of the tensile strength, flexibility, or compressibility of the bending portion to change.

Optionally, the housing is positioned around the longitudinal axis of the screw and is configured to move longitudinally along said axis.

The present specification also discloses an endoscope assembly comprising an insertion portion that is connected to a handle at a proximal end of the insertion portion and a bending portion at a distal end of the insertion portion, comprising: an actuator; a spring, having a proximal end and a distal end, wherein the proximal end of the spring is connected to the actuator and wherein the actuator activates the spring; and, a wire, having a proximal end and a distal end, with the proximal end of the wire connected to the distal end of the spring, wherein the wire stretches along a length of the insertion portion and wherein the distal end of the wire is connected to a proximal end of the bending portion, and wherein the wire stiffens the insertion portion upon activation of the spring.

The spring may comprise superelastic material. Optionally, the superelastic material is Nitinol.

Optionally, the actuator is connected to an electric current source that activates the spring. Optionally, the actuator is connected to a heat source that activates the spring. Still optionally, the actuator is connected to a gear motor that activates the spring.

Optionally, the endoscope assembly further comprises a shaft connecting the spring and the wire. The shaft may have a U-shaped structure comprising: a first wall connected to distal end of the spring; and a second wall, parallel to the first wall, connected to the proximal end of the wire.

The wire may be placed inside a coil fixed to an internal periphery of the insertion portion.

Optionally, the endoscope assembly further comprises a housing containing at least one of the actuator, the spring, and the wire.

The present specification also discloses an endoscope assembly comprising an insertion portion that is connected to a handle at a proximal end of the insertion portion and a bending portion at a distal end of the insertion portion, comprising: an actuator; a tube with slits centered and stretching along its longitudinal axis across a portion of its length, the tube having a proximal end and a distal end, wherein the proximal end of the tube is connected to the actuator, and wherein the actuator activates the tube; and, a wire, having a proximal end and a distal end, the proximal end of the wire connected to the tube, wherein the wire stretches along a length of the insertion portion and the distal end of the wire is connected to a proximal end of the bending portion, wherein the wire stiffens the insertion portion upon activation of the tube.

The tube may be manufactured with a superelastic material. Optionally, the superelastic material is Nitinol.

The present specification also discloses an endoscope assembly comprising an insertion portion that is connected to a handle at a proximal end of the insertion portion and a bending portion at a distal end of the insertion portion, comprising: a wheel, approximately shaped as an ellipse, wherein said wheel further comprises a first portion, a second portion, and a center portion; a shaft connected to a center of the wheel; a lever connected to the shaft, wherein rotation of the lever rotates the shaft and the wheel; a wire having a proximal end and a distal end, wherein the proximal end of the wire rests on an edge of the wheel, the wire stretches along a length of the insertion portion and the distal end of the wire is connected to a proximal end of the bending portion and wherein the wire stiffens the insertion portion upon rotation of the wheel; and a stopper connected to the proximal end of the wire, wherein the stopper anchors the wire with the wheel.

The present specification also discloses an endoscope assembly comprising a working channel, wherein the outer periphery of the working channel is covered with an enforcement layer providing stiffness to the working channel.

Optionally, the enforcement layer is manufactured from a material comprising at least one metal from family of stainless steel metals.

The present specification also discloses an insertion portion in an endoscope assembly, comprising: at least one flexible tube extending from a proximal end of the insertion portion along length of the insertion portion; a pressure pump connected to the at least one flexible tube at the proximal end of the insertion portion; and a fluid inflating the at least one flexible tube, wherein a pressure of the fluid is controlled by the pressure pump.

Optionally, the fluid is at least one of water, a fluid that changes viscosity based on an applied electric field, a fluid that changes viscosity based on shear rate or shear rate history, a fluid that changes viscosity based on a magnetic field, and a fluid that changes viscosity based on exposure to light.

The fluid may be water sourced from a water supply of the endoscope assembly.

Optionally, varying an operating voltage of the pressure pump controls pressure of the fluid.

A pressure regulator may be connected to the pressure pump to control pressure of the fluid.

Optionally, the at least one flexible tube extending from a proximal end of the insertion portion extends up to a proximal end of bending section of the insertion portion and not into a tip section of the endoscope assembly.

Optionally, the at least one flexible tube extending from a proximal end of the insertion portion extends up to a distal end of the insertion portion.

Still optionally, the at least one flexible tube extending from a proximal end of the insertion portion extends up to an opposite end of the flexible tube, wherein the opposite end is sealed.

The pressure pump may control pressure of the fluid to control flexibility of the at least one flexible tube.

The present specification also discloses an insertion portion in an endoscope assembly, comprising: a flexible tube coiled around an outer circumferential surface of a treatment tool insertion channel embedded inside the insertion portion, the coiled tube extending from a proximal end of the insertion portion along a length of the insertion portion; a pressure pump connected to the flexible tube at the proximal end of the insertion portion; and a fluid inflating the flexible tube, wherein a pressure of the fluid is controlled by the pressure pump.

Optionally, the flexible tube extending from a proximal end of the insertion portion extends up to a proximal end of bending section of the insertion portion and not into said tip section.

Optionally, the flexible tube extending from a proximal end of the insertion portion extends only up to a distal end of the insertion portion.

Still optionally, the flexible tube extending from proximal end of the insertion portion extends up to an opposite end of the flexible tube, wherein the opposite end is sealed.

The pressure pump may control pressure of the fluid to control flexibility of the flexible tube.

The present specification also discloses an insertion portion in an endoscope assembly, comprising: at least one flexible lining stretching along an inner wall of the insertion portion, the flexible lining forming a parallel wall inside the insertion portion such that a gap exists between the parallel wall and the inner wall of the insertion portion, and extending from a proximal end of the insertion portion along a length of the insertion portion; a pressure pump connected to the gap at the proximal end of the insertion portion; and a fluid filling the gap, wherein a pressure of the fluid is controlled by the pressure pump.

The present specification also discloses an insertion portion in an endoscope assembly, comprising: at least one flexible tube extending from a proximal end of the insertion portion along a length of the insertion portion, wherein the flexible tube encloses a gas; at least one sealed chamber into which the at least one flexible tube opens and carries gas into the at least one sealed chamber; and a pressure pump connected to the at least one flexible tube at the proximal end of the insertion portion, wherein a pressure of gas is controlled by the pressure pump.

Optionally, three flexible tubes open into three corresponding sealed chambers.

Each chamber may be located adjacent to one another along a longitudinal axis of the insertion portion.

Each chamber may be concentrically located along a longitudinal axis of the insertion portion.

The aforementioned and other embodiments of the present specification shall be described in greater depth in the drawings and detailed description provided below.

These and other features and advantages of the present specification will be further appreciated, as they become better understood by reference to the detailed description when considered in connection with the accompanying drawings:.

The present specification is directed towards multiple embodiments. The following disclosure is provided in order to enable a person having ordinary skill in the art to practice the specification. Language used in this specification should not be interpreted as a general disavowal of any one specific embodiment or used to limit the claims beyond the meaning of the terms used therein. The general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the specification. Also, the terminology and phraseology used is for the purpose of describing exemplary embodiments and should not be considered limiting. Thus, the present specification is to be accorded the widest scope encompassing numerous alternatives, modifications and equivalents consistent with the principles and features disclosed. For purpose of clarity, details relating to technical material that is known in the technical fields related to the specification have not been described in detail so as not to unnecessarily obscure the present specification.

It is noted that the term "endoscope" as mentioned to herein may refer particularly to a colonoscope and a gastroscope, according to some embodiments, but is not limited only to colonoscopes and/or gastroscopes. The term "endoscope" may refer to any instrument used to examine the interior of a hollow organ or cavity of the body, provided it further includes an insertion section, bending portion, and viewing tip as described herein.

Reference is now made to <FIG>, which shows a multiple viewing elements endoscopy system <NUM>, in accordance with some embodiments. System <NUM> may include a multiple viewing elements endoscope <NUM>, having a multiple viewing elements tip section <NUM>. Multiple viewing elements endoscope <NUM> may include a handle <NUM>, from which an elongated shaft <NUM> emerges. Elongated shaft <NUM> terminates with a tip section <NUM>, which can be turned by way of a bending section <NUM>. Handle <NUM> may be used to maneuver elongated shaft <NUM> within a body cavity. The handle <NUM> may include one or more knobs and/or switches <NUM> that control bending section <NUM> as well as functions such as fluid injection and suction. Handle <NUM> may further include a working channel opening <NUM> through which surgical tools may be inserted, as well as one or more side service channel openings.

A utility cable <NUM> may connect between handle <NUM> and a main control unit <NUM>. Utility cable <NUM> may include therein one or more fluid channels and one or more electrical channels. The electrical channel(s) may include at least one data cable to receive video signals from the front and side-pointing viewing elements, as well as at least one power cable to provide electrical power to the viewing elements and to the discrete illuminators. Main control unit <NUM> governs a plurality of operational functionalities of the endoscope. For example, main control unit <NUM> may govern power transmission to the endoscope's <NUM> tip section <NUM>, such as for the tip section's viewing elements and illuminators. Main control unit <NUM> may further control one or more fluid, liquid and/or suction pump, which supply corresponding functionalities to endoscope <NUM>. One or more input devices, such as a keyboard <NUM>, may be connected to main control unit <NUM> for the purpose of human interaction with main control unit <NUM>. In another configuration (not shown), an input device, such as a keyboard, may be integrated with main control unit <NUM> in a same casing.

A display <NUM> may be connected to main control unit <NUM>, and configured to display images and/or video streams received from the viewing elements of multiple viewing elements endoscope <NUM>. Display <NUM> may further be operative to display a user interface to allow a human operator to set various features of system <NUM>.

Optionally, the video streams received from the different viewing elements of multiple viewing elements endoscope <NUM> may be displayed separately on display <NUM>, either side-by-side or interchangeably (namely, the operator may switch between views from the different viewing elements manually). Alternatively, these video streams may be processed by main control unit <NUM> to combine them into a single, panoramic video frame, based on an overlap between fields of view of the viewing elements.

In another configuration (not shown), two or more displays may be connected to main control unit <NUM>, each to display a video stream from a different viewing element of the multiple viewing elements endoscope.

Referring now to <FIG>, a view of a scope handle <NUM> of an endoscope, such as endoscope <NUM> of <FIG>, is shown. Handle <NUM> includes various components such as an umbilical tube <NUM> that connects its control head to a supply plug at the end of a utility cable, such as utility cable <NUM> of <FIG>. The control head on handle <NUM> includes knobs <NUM> to enable turning of a bending section as well as for functions such as fluid injection and suction. Additionally, handle <NUM> may include switches/buttons <NUM>. Both knobs <NUM> and buttons <NUM> may provide multiple controlling functions. The figure also shows the position of a working channel opening <NUM> through which surgical tools may be inserted. An insertion portion <NUM> (shown in part) emerges from handle <NUM>, and has been described as elongated shaft <NUM> in context of <FIG>. For purposes of describing the specification, elongated shaft will be known as the 'insertion portion', since it is the part of the endoscope assembly that is inserted inside a body cavity. In embodiments, at a proximal end, handle <NUM> connected to insertion portion <NUM> maneuvers it within the body cavity.

<FIG> illustrates a cross-sectional view of a portion of handle <NUM> extending from near working channel opening <NUM> towards the beginning of insertion portion <NUM>. In embodiments, handle <NUM> includes an actuator <NUM> that is responsible for activating a spring <NUM>, thus allowing the spring <NUM> to modulate its degree of elasticity to change its stiffness. In the embodiments of the present specification, activating is defined as being at least one of modifying the pitch, length, degree of compression, or degree of expansion of the spring. In various embodiments, the spring is any one of a tension/extension spring, compression spring, constant spring, variable spring, coil spring, flat spring, machined spring, In embodiments, actuator <NUM> and spring <NUM> are manufactured with Nitinol. Nitinol is an alloy of Nickel and Titanium, and is known for its properties of shape memory and super elasticity. Nitinol deforms at low temperatures and recovers its original shape when heated. In embodiments, this property is used to control or vary the stiffness of insertion portion <NUM>.

In embodiments, a first end of a wire <NUM> is connected to a shaft over which spring <NUM> is wound, inside a housing. In the embodiments of the present specification, a wire comprises any single, cylindrical, flexible strand or rod of metal or any member capable of having its extent or degree of mechanical load bearing be modulated. Movement of spring <NUM> influences stiffness of wire <NUM>. A second end of wire <NUM> may be connected to a proximal end of a bending section within insertion portion <NUM>. Therefore, movement of spring <NUM> influences the stiffness of insertion portion <NUM> along its entire length. In embodiments, a coil <NUM> is wound around wire <NUM> to protect it and enable movement of wire <NUM>. In the embodiments of the present specification, movement of the wire causes at least one of the pitch, degree of expansion, degree of compression, and flexibility of the coil to change. In addition, in the embodiments of the present specification, movement of the wire causes at least one of the tensile strength, flexibility, or compressibility of the bending section of the endoscope to change.

Referring now to <FIG>, another cross-sectional view of spring <NUM> and related arrangements is illustrated in accordance with some embodiments. A housing <NUM> accommodates spring <NUM> and a dynamic shaft <NUM>. Housing <NUM> stretches across the length of spring <NUM>, and has two ends - a proximal end <NUM> and a distal end <NUM>, which may be proximal and distal respectively to a beginning of the handle of the endoscope. Shaft <NUM> is connected to a distal end of actuator <NUM> inside housing <NUM>. The proximal end of actuator <NUM> may continuously exit housing <NUM> towards a source of energy that actuates spring's <NUM> movements. Spring <NUM> is wound around a tubular length of actuator <NUM>, positioned inside housing <NUM>. A proximal end of spring <NUM> is fixed to the internal surface of proximal end <NUM> of housing <NUM>. A distal end of spring <NUM> is fixed to shaft <NUM>.

In one embodiment, shaft <NUM> is a U-shaped structure, where the two straight parallel edges of its U-shape may be referred to as a first wall <NUM> and a second wall <NUM>, positioned parallel to one another, each having internal and external surfaces. First and second walls <NUM>, <NUM>, may be connected to each other with a flat base <NUM> completing the U-shaped form. Wall <NUM>, which is on the proximal side, connects to spring <NUM> on its external surface, while wall <NUM> on the distal side, is pierced by, or generally attached to, wire <NUM>. Wire <NUM> enters shaft <NUM> from the external surface of wall <NUM> and is held in place by a stopper <NUM> on the other side of wall <NUM>. Thus, stopper <NUM> aids in anchoring of wire <NUM> inside housing <NUM>. The distal end of wire <NUM> continuously exits distal end <NUM> of housing <NUM>, opposite to the side where actuator <NUM> exits housing <NUM>. Outside housing <NUM>, wire <NUM> is protected by coil <NUM> that is fixed to the internal surface of the insertion portion.

Referring now to <FIG>, <FIG>, exemplary embodiments of energy sources for an actuator, such as actuator <NUM>, are illustrated. <FIG> illustrates an actuator <NUM> that may be energized by an electric current. In embodiments, actuator <NUM> may comprise two parallel terminals 402a and 402b that are connected to each end of spring <NUM>. In an embodiment, terminal 402a is connected to proximal end of spring <NUM>, and terminal 402b is connected to distal end of spring <NUM>. Any one of the two terminals may be connected to an anode, while the other is connected to a cathode. Electric current may pass through the two terminals, resulting in activation of spring <NUM>, thus allowing spring <NUM> to modulate its degree of elasticity to change its stiffness. In embodiments, actuator <NUM> and spring <NUM> are manufactured with Nitinol. Nitinol is an alloy of Nickel and Titanium, and is known for its properties of shape memory and superelasticity, namely an elastic, reversible response to applied stress. Nitinol deforms at low temperatures and recovers its original shape when heated or placed at low temperatures. Electric current passing through the two terminals heat actuator <NUM> and as a result spring <NUM> is also heated, thereby contracting spring <NUM>, resulting in increased stiffness of a wire <NUM>. The second end of wire <NUM>, connected to the proximal end of the bending section within the insertion portion, therefore increases the stiffness of the insertion portion along its entire length. In embodiments, property of superelasticity is used to control or vary the stiffness of the insertion portion.

<FIG> illustrates an actuator <NUM> that may be energized by a heating body or heat source, such as but not limited to resistance based heater. Actuator <NUM> is heated, due to thermal conductivity and/or heat transfer from the heating body or heat source. Thus, actuator <NUM> may be a heat body connected to a spring <NUM> along the length of the shaft over which spring <NUM> is wound. In embodiments, heating the actuator <NUM> activates spring <NUM>, which may be manufactured from a super-elastic material such as Nitinol. Temperature changes applied on the two terminals of heat actuator <NUM> also causes spring <NUM> to be heated, thereby causing spring <NUM> to be in a first configuration, or its original shape, which results in an increase in the stiffness of the insertion portion via pulling or stretching of wire <NUM>. In embodiments, the superelastic property is used to control or vary the stiffness of the insertion portion.

In another embodiment, reduction of temperature of actuator <NUM> and therefore that of spring <NUM> results in deformation of both (due to Nitinol deforming at low temperatures), owing to their superelastic property. As a result, lowering the temperature of actuator <NUM> in order to cool it results in spring <NUM> to be brought to a second configuration, which causes contraction of wire <NUM> and subsequently, an increase in the stiffness of the insertion portion. In embodiments, a coolant is used to cool actuator <NUM> and spring <NUM>.

The extent of stiffness of the insertion tube is therefore controlled by changing temperature of the structure, and therefore of the properties of the wire <NUM>, such that the wire is either pushed or contracted or pulled or expanded.

In yet another embodiment, <FIG> illustrate a gear motor <NUM> that drives a dynamic shaft <NUM> connected to a wire <NUM> placed inside the endoscope's insertion portion. In one embodiment, shaft <NUM> is a U-shaped structure, where the two straight parallel edges of its U-shape may be referred to as a first wall <NUM> and a second wall <NUM>, positioned parallel to one another, each having internal and external surfaces. First and second walls <NUM>, <NUM>, may be connected to each other with a flat base <NUM>, thus completing the U-shape. Wire <NUM> stretches over the complete length of the insertion portion and is connected to shaft <NUM> at proximal end of wire <NUM>. First wall <NUM> of shaft <NUM> is connected to wire <NUM> while a proximal end of second wall <NUM> is connected to an actuator <NUM> driven by gear motor <NUM>. In embodiments, operation of gear motor <NUM> results in stiffening or relaxing of wire <NUM> with backward or forward movements of shaft <NUM>, respectively, that is pulled by gear motor <NUM>.

Referring now to <FIG>, another cross-sectional view of spring <NUM> and related arrangements described in context of <FIG> and <FIG> is illustrated in accordance with some embodiments. Embodiments of <FIG> include wire, coil, and housing configurations (not labelled) similar to those described in context of <FIG> and <FIG>. Hereinafter, wire <NUM> coil <NUM>, housing <NUM>, and distal end <NUM> of housing <NUM>, also refer to similar configurations described for <FIG>. In embodiments, coil <NUM> is wound around wire <NUM> to protect it and enable movement of wire <NUM>. An arrow <NUM> illustrates an exemplary direction of movement of spring <NUM>. Movement in one direction may stretch spring <NUM>, such that spring <NUM> lengthens. As a result, wire <NUM> also relaxes and decreases the stiffness of the insertion portion, which may make the insertion portion more flexible. Movement in an opposite direction may tighten spring <NUM>, resulting in a tightening of wire <NUM> and an increase in the stiffness of the insertion portion. Actuator <NUM>, also described above with respect to <FIG>, causes movement of spring <NUM>. An energized actuator <NUM> may activate spring <NUM>, which results in the tightening of spring <NUM>. Alternatively, when the energy is not provided to actuator <NUM>, or its source is interrupted, spring <NUM> may return to a loosened or stretched state. While actuator <NUM> may energize and activate a Nitinol spring causing it to stiffen, in certain embodiments utilizing a mechanical means to move actuator <NUM> may similarly stiffen or deform spring <NUM> by a mechanical movement. In embodiments, wire <NUM> is placed inside coil <NUM>, which is positioned outside of housing <NUM>. Coil <NUM> is fixed to an internal surface of the insertion portion along its length, and is also fixed to an external surface of distal end <NUM> of housing <NUM>. As a result, when spring <NUM> is stiffened, wire <NUM> is pulled, resulting from the pulling motion by actuator <NUM>.

In operation, as actuator <NUM> is energized, spring <NUM> is activated. Activation of spring <NUM> results in a change in its shape owing to superelastic properties of Nitinol. Consequently, dynamic shaft <NUM> moves while pulling or pushing wire <NUM>, as wire <NUM> is also connected to shaft <NUM>. The stiffness character of the insertion portion is influenced by pulling or pushing the wire, influenced respectively by heating or cooling actuator <NUM>. In embodiments, controlling the amount of energy provided to actuator <NUM> may further control the degree of stiffness of the insertion portion. In embodiments, a controller to control the degree of energy provided to actuator <NUM> and therefore the degree of stiffness of the insertion portion is provided in either the handle of the endoscope, the main control unit connected to the endoscope, through a foot pedal attached to the endoscope, or through any other means. The control mechanism may be provided through an interface such as a push button, a valve, a nob, or any other digital or analogue interface. As the energy provided to actuator <NUM> is increased, wire <NUM> is pulled more, and the degree of stiffness increases. In embodiments, one or more screens connected to the system may display the use of a control to control the stiffness, and may even display a degree of stiffness achieved through the control. For example a display may illustrate the stiffness in effect through a binary illustration, such as whether the insertion tube is or is not stiff. In another example, a display may indicate a degree of stiffness over a numerical or any other scale, such as <NUM> to <NUM>, where <NUM> may be first degree of stiffness and <NUM> may be the highest degree of stiffness that can be applied to the insertion tube, or vice versa. In yet another example, also illustrated in <FIG>, a degree of stiffness may be indicated through a display <NUM> by means of a slider <NUM> between standard "+" and "-" symbols <NUM> and <NUM>, respectively indicating maximum and minimum degrees of stiffness.

<FIG> illustrates an alternative embodiment of an arrangement to manipulate and vary the stiffness of an insertion portion in an endoscope. In this embodiment, the spring is replaced by a tube <NUM>, which is also manufactured with Nitinol. Tube <NUM> comprises slits <NUM> along its tubular walls, and along its longitudinal axis. The slits <NUM> may stretch across a portion of tube <NUM> and may be centered at the center of the total length of tube <NUM>. In embodiments, the slits <NUM> are typically equidistant from each other, spaced throughout the circumference of tube <NUM>. Similar to the previous embodiment, tube <NUM> may be placed over an actuator <NUM>, inside a housing <NUM>. Housing <NUM> accommodates tube <NUM> and a dynamic shaft <NUM>. Housing <NUM> may stretch across the length of tube <NUM>, and have two ends - a proximal end <NUM> and a distal end <NUM>, which may be proximal and distal respectively to a beginning of the handle of the endoscope. Shaft <NUM> may be connected to a distal end of actuator <NUM> inside housing <NUM>. The proximal end of actuator <NUM> may continuously exit housing <NUM> towards a source of energy that actuates tube's <NUM> movements. Tube <NUM> may be placed around a tubular length of actuator <NUM>, positioned inside housing <NUM>. Proximal end of tube <NUM> is fixed to internal surface of proximal end <NUM> of housing <NUM>. Distal end of tube <NUM> is fixed to shaft <NUM>.

In one embodiment, shaft <NUM> is a U-shaped structure, where the two straight parallel edges of its U-shape may be referred to as a first wall <NUM> and a second wall <NUM>, positioned parallel to one another, each having internal and external surfaces. First and second walls <NUM>, <NUM>, may be connected to each other with a flat base <NUM>, thus completing the U-shape. External surface of wall <NUM>, which is on the proximal side of the endoscope handle, connects to tube <NUM>, while wall <NUM> on the distal side, is pierced by wire <NUM>. Wire <NUM> enters shaft <NUM> from the external surface of wall <NUM> and is held in place by a stopper <NUM> on the other side of wall <NUM>. Thus, stopper <NUM> aids in anchoring of wire <NUM> within the inside of housing <NUM>. The distal end of wire <NUM> continuously exits distal end <NUM> of housing <NUM>, opposite to the side where actuator <NUM> exits housing <NUM>. Outside housing <NUM>, a coil <NUM> that is fixed to the internal surface of insertion portion <NUM> protects wire <NUM>. An arrow <NUM> illustrates exemplary direction of movement of tube <NUM>, which is caused by energising or de-energising of actuator <NUM>. Actuator <NUM> may be one of several embodiments described previously, such as in context of <FIG>, <FIG>. Additionally, operation of tube <NUM> mechanism may be similar to operation of spring <NUM> mechanism, similar to that described in context of <FIG>.

<FIG> illustrates a portion of an endoscope handle with an elliptical wheel mechanism <NUM> that enables variable stiffness of an insertion portion <NUM> of the endoscope. In an embodiment, an elliptical wheel <NUM> comprises two side portions - a first side portion <NUM> and a second side portion <NUM> that sandwich a center portion. The edges of first portion <NUM> and second portion <NUM> rest slightly above the center portion of the sandwich. Thus, the diameter of first portion <NUM> and second portion <NUM> is larger than the diameter of the center portion. In embodiments, a wire <NUM> rests on an outer edge of the center portion, between two sides <NUM> and <NUM> of wheel <NUM>. In embodiments, wire <NUM> is connected at its proximal end to a stopper <NUM>. Stopper <NUM> rests against edges two sides <NUM> and <NUM> of wheel <NUM>. Wheel <NUM> may have a shape similar to that of an ellipse. In embodiments, one or both of the longer edges of elliptical wheel <NUM> may have an indentation such that the indentation provides a recess or a notch for stopper <NUM> to rest and stop rotation of wheel <NUM>. Thus, stopper <NUM> enables anchoring of wire <NUM> with wheel <NUM>. At its other end, wire <NUM> is connected to a proximal end of a bending section within insertion portion <NUM>. In embodiments, wire <NUM> is placed inside a coil <NUM>. Coil <NUM> enables movement of wire <NUM>, and is fixed to the internal surface of insertion portion <NUM>.

In embodiments, wheel <NUM> is connected to a shaft <NUM>, which in turn is connected to a lever <NUM>. Thus, lever <NUM> operates wheel <NUM>. In embodiments, lever <NUM> is manually operated, and the extent of its rotation influences the degree of stiffness of insertion portion <NUM>. In operation, rotation of lever <NUM> rotates wheel <NUM>, which influences wire <NUM>. Consequently, wire <NUM> either tightens or relaxes, based on the direction of rotation of lever <NUM>.

<FIG> illustrates another perspective view of the endoscope handle with the elliptical wheel arrangement of <FIG>. In the arrangement, wheel <NUM> is located at a proximal end of the endoscope's handle, and wire <NUM> extends towards a distal end into insertion portion <NUM>.

<FIG> illustrates an enlarged two-dimensional view of assembly <NUM>, in accordance with some embodiments. In embodiments, wheel <NUM> has an asymmetric shape, similar to an ellipse. In this figure, one side <NUM> is visible, and the second side cannot be seen. Central edge of wheel <NUM> is also hidden behind side <NUM>, between the two sides. Wire <NUM> is seen connected to stopper <NUM> and passing over the central edge of wheel <NUM>. The concentric center of elliptical wheel <NUM> allows its radius to increase as wheel <NUM> rotates. Increased radius results in tightening of wire <NUM>. Shaft <NUM>, connected to lever <NUM>, rotates with the movement of lever <NUM>. Wheel <NUM> is placed on shaft <NUM> and rotates with it. In embodiments, wire stopper <NUM> is adapted to fix position of wire <NUM> relative to wheel <NUM>. In embodiments, one of the longer edges of elliptical wheel <NUM> may have an indentation such that the indentation provides a recess or a notch for stopper <NUM> to rest and stop rotation of wheel <NUM>. Thus, stopper <NUM> enables anchoring of wire <NUM> with wheel <NUM>. At its other end, wire <NUM> is connected to a proximal end of a bending section within insertion portion <NUM>. Once the wheel stops rotating, wire <NUM> may not move further around outer edge of centre portion of wheel <NUM>, thus fixing location of wire <NUM> relative to wheel <NUM>.

<FIG> and <FIG> illustrate cross-sectional views <NUM> of another embodiment for varying the stiffness of an insertion portion <NUM> of an endoscope involving a screw mechanism located within the handle of an endoscope. Simultaneously referring to <FIG> and <FIG>, the mechanism includes a screw <NUM> placed within a housing <NUM> located in the handle of the endoscope. In embodiments, housing <NUM> further includes an internal housing (further illustrated in <FIG>) to house a wire stopper <NUM>. In embodiments, internal housing moves in accordance with a tightening/releasing movement of screw <NUM>, in a direction that is at least one of a distal direction and a proximal direction along the longitudinal axis of the endoscope assembly. In embodiments, a proximal end of a wire <NUM> is connected to stopper <NUM>. Distal end of wire <NUM> is connected to a proximal side of a bending portion at distal end of insertion portion <NUM>. In embodiments, an opening <NUM> in the endoscope handle provides an optimal space and location suitable to place the screw mechanism in accordance with described embodiments. In some embodiments, a knob on the handle, such as knob <NUM> described with reference to <FIG>, may be used to rotate the screw <NUM>. The knob is in communication with the screw such that a rotation of the knob causes a rotation of the screw. In some embodiments, the physical connection between the knob and the screw <NUM> may be geared such that a large rotation of the knob <NUM> would cause a smaller rotation of the screw or a small rotation of the knob would cause a larger rotation of the screw <NUM>.

Referring to <FIG> in combination with <FIG> and <FIG>, a three-dimensional view of the screw mechanism of <FIG> and <FIG> is illustrated. In addition to components described in context of <FIG> and <FIG>, <FIG> illustrates an internal housing <NUM>, placed within housing <NUM>. Internal housing <NUM> moves with tightening/releasing of screw <NUM>. In embodiments, as screw <NUM> is tightened, internal housing <NUM> moves in a direction of its proximal end <NUM>, towards a proximal end <NUM> of housing <NUM>. In operation, screw <NUM> may be rotated around a longitudinal axis of the endoscope's handle. Rotating screw <NUM> may cause internal housing <NUM> to move along the longitudinal axis. In embodiments, rotation of screw in a clock-wise direction <NUM> may move internal housing <NUM> in a proximal direction <NUM>, towards a proximal end of the endoscope's handle. In embodiments, distal end of wire <NUM> is connected to a proximal end of a bending section within the endoscope. In embodiments, wire <NUM> is placed within a coil <NUM>, which enables movement of wire <NUM>. Coil <NUM> is fixed to the internal surface of insertion portion <NUM>.

Screw <NUM> is connected to proximal end <NUM>. In embodiments, screw <NUM> is screwed inside internal housing <NUM> through its proximal end <NUM>. Rotation of screw <NUM> moves internal housing <NUM> closer to proximal end <NUM> of housing <NUM>, in proximal direction <NUM>. Consequently, wire <NUM> is pulled resulting in stiffening of the insertion portion. When screw <NUM> is released, internal housing <NUM> moves towards a distal end <NUM> of housing <NUM>, resulting in a relaxed insertion portion. Therefore, movement of screw <NUM> influences tightening or loosening of wire <NUM>.

In embodiments, an opening <NUM> in the endoscope handle provides an optimal space and location suitable to place the screw mechanism in accordance with described embodiments. <FIG> illustrates housing <NUM> and the screw mechanism placed inside opening <NUM> in a handle <NUM> of the endoscope. In embodiments, internal design of scope handle <NUM> allows secure placement of the screw mechanism. <FIG> illustrates a view of handle <NUM> when it is open. Once handle <NUM> is closed and locked, the screw mechanism is invisible, secure, and intact. The mechanism may be operated, likely to tighten screw <NUM>, during a maintenance activity when handle <NUM> is unlocked and opened to reveal the screw mechanism.

Referring to <FIG> and <FIG>, an additional embodiment is described, which influences stiffness of an insertion portion of an endoscope. <FIG> illustrates a cross-sectional view of a handle <NUM>. A service channel opening leads to a working channel <NUM> inside handle <NUM>. Working channel <NUM> extends towards tip section of the endoscope, stretching over entire length of an insertion portion <NUM>. In embodiments, an enforcement layer <NUM> is placed over an outer periphery of working channel <NUM>. In embodiments, layer <NUM> may be manufactured from a metal that is from the family of stainless steel metals, or any other material that may stiffen working channel <NUM> such that utility of working channel <NUM> remains unaffected. Physicians are able to insert surgical tools and/or equipment to perform procedures through working channel <NUM> that is covered by layer <NUM>. Working channel <NUM> stretches over entire length of insertion portion <NUM>, therefore layer <NUM> may influence stiffness characteristic of insertion portion <NUM>, for example by providing permanent stiffness to insertion portion <NUM>.

<FIG> illustrates a cross-sectional view of working channel <NUM> inside the endoscope handle. The figure also clearly illustrates enforcement layer <NUM> on the outer periphery of working channel <NUM>.

Although the present specification has been described with particular focus on an actuator that can controls a super-elastic element in order to vary stiffness of an insertion portion in an endoscope assembly, the present specification is also designed to vary stiffness through means of fluid and gas provided within the insertion portion. Therefore, various embodiments of the present specification describe elements (solid, liquid, and gas) that are controlled through different mechanisms to vary stiffness of an insertion portion in an endoscope.

Referring now to <FIG>, a longitudinal cross-sectional view of a portion of an elongated shaft in an endoscope is shown, in accordance with some embodiments. For purposes of describing the specification, elongated is termed as the 'insertion portion', since it is the part of the endoscope assembly that is inserted inside a body cavity.

An insertion portion <NUM> terminates at a tip section <NUM>, which is at the distal end (that is, the end that is farthest from the endoscope handle) of insertion portion <NUM>. In embodiments, at a proximal end, a handle connected to insertion portion <NUM> assists/help maneuvers the insertion portion within the body cavity. The arrangement of these components is described above with reference to <FIG>. In some embodiments, a flexible tube <NUM> extends from the proximal end of insertion portion <NUM> along its entire length. In embodiments, flexible tube <NUM> is a separate tube outside a working channel and inside insertion portion <NUM>. In embodiments, length of flexible tube <NUM> may vary with the length of insertion portion <NUM>. Diameter of flexible tube <NUM> may also vary to adapt to the endoscope device where is it embedded. In embodiments, flexible tube <NUM> may have an amorphous shape that adapts to space available within insertion portion <NUM>. In embodiments, flexible tube <NUM> is manufactured with a polymer that is used for conductivity of fluid under pressure. Examples of such polymer may include, but are not limited to, Polyurethane, Polyamide, Polyethylene, Polypropylene, Nylon, Silicon, and TPE.

The illustrated embodiment shows flexible tube <NUM> terminating at tip section <NUM>. In alternative embodiments, flexible tube <NUM> terminates some distance prior to tip section <NUM>, and within the bending section of insertion portion <NUM>. In other embodiments, flexible tube <NUM> terminates just before a first vertebra of the bending section, or at a proximal end of the bending section. In embodiments, flexible tube <NUM> is configured to enclose a fluid, such as but not limited to water. In embodiments where water inflates flexible tube <NUM>, the water may be sourced from the same supply that feeds the injector channel. Flexible tube <NUM> may be sealed at its distal end, referred to as a sealed end <NUM>, such that it carries a volume of water enclosed within flexible tube <NUM>. An increase in this volume results directly in an increase of pressure of the water inside the flexible tube <NUM>, which, in turn, results in an increase in stiffness (or decrease in flexibility) of flexible tube <NUM>. Conversely, a decrease in this volume results directly in a decrease of pressure of the water inside the flexible tube <NUM>, which, in turn, results in a decrease in stiffness (or increase in flexibility) of flexible tube <NUM>. This arrangement also affects the overall flexibility of insertion portion <NUM>, thus enabling control over its maneuverability inside a body cavity.

In embodiments, a pressure pump <NUM> is connected to flexible tube <NUM> at the proximal end of insertion portion <NUM>. In alternative embodiments, pressure pump <NUM> is connected through the handle to flexible tube <NUM>. Pressure pump <NUM> may control the pressure of water inside flexible tube <NUM>. Pressure control may be enabled through a button, a switch, or a knob located on the handle or on a main control unit of the endoscope assembly or by a foot pedal. The control may adjust the pressure by varying an operating voltage or by using a pressure regulator. In embodiments, water is input at an inlet <NUM> of pump <NUM>. Water of variable pressure may be output through an outlet <NUM>, which feeds into flexible tube <NUM>. In embodiments, a user/physician interfaces with a scale that allows selection of a stiffness percentage, such as in the range of <NUM>% to <NUM>%. <NUM>% may represent an insertion portion stiffness without any pressure, inside flexible tube <NUM>. And <NUM>% may represent insertion portion <NUM> with the maximum pressure that may be applied inside flexible tube <NUM>. A percentage value within this range may vary based on user requirements.

In alternative embodiments, other fluids may be used in place of water, within flexible tube <NUM>. Variable viscosity of a fluid may contribute to variation in stiffness of flexible tube <NUM> containing the fluid. Therefore, any fluid that may change its viscosity properties may be used within flexible tube <NUM>. In embodiments, the fluid within flexible tube <NUM> may undergo a viscosity change due to a change in at least one of temperature, electric charge, magnetic field, exposure to light, or any other factor influencing viscosity. Examples of such fluids may include, but are not limited to, electrorheological fluids that change viscosity based on an applied electric field, non-Newtonian fluids that change viscosity based on shear rate or shear rate history, magnetorheological fluids that change viscosity based on a magnetic field, photo-rheological fluids that change viscosity based on exposure to light, and the like.

In embodiments, electrorheological fluids (ERFs) are material composed of dielectric properties suspended in an insulating oil. Flow characteristics of ERFs may depend on properties of the dispersed material and the oil. Examples of ERFs include dispersions consisting of oil (mineral or silicon oil) and solid polymer particles, Hydroxyl-terminated silicon oil, RheOil®, and the like. In embodiments, magnetorheological fluids (MRFs) are liquids that display adjustable flow properties through introduction of magnetic fields. As a result, their characteristics can be changed from free flowing to solid and back again in a few milliseconds. Examples of MRF include fluid made using Carbonyl Iron powder, hydrocarbon-based MRFs, and the like.

In embodiments, pump <NUM> is a lightweight pump suitable for liquids that provides a high-pressure capability for a small device. Pump <NUM> may be a small-sized pump that delivers a consistent flow throughout a wide range of varying pressures. In embodiments, an electronic driver circuit may be used to operate the motor of pump <NUM>.

<FIG> also illustrates a horizontal cross sectional view of insertion portion <NUM> above its longitudinal cross-sectional view. This view shows an exemplary position of flexible tube <NUM> within insertion portion <NUM>. Flexible tube <NUM> is seen positioned at the radial center of insertion portion <NUM>. Thus, flexible tube <NUM> enables variation in flexibility of insertion portion <NUM> from within and from its center. In another embodiment, flexible tube <NUM> may be positioned in an empty space within and along insertion portion <NUM>. In embodiments, such empty spaces may include but are not limited to spaces between electronic wires, working channels, and air/water channel(s).

In an alternative embodiment, flexible tube <NUM> is coiled around an outer circumferential surface of a treatment tool insertion channel, such as a working channel, embedded within insertion portion <NUM>. In this case, flexible tube <NUM> coils around entire length of the working channel extending from the proximal end of insertion portion <NUM>. In another embodiment, flexible tube <NUM> coils around the working channel and terminates some distance prior to the bending section of insertion portion <NUM>.

In yet another embodiment, flexible tube <NUM> is replaced with a flexible lining that extends from a proximal end of insertion portion <NUM> along length of insertion portion <NUM>. The flexible lining may form a tubular wall concentric to the inner wall of insertion portion <NUM> such that a gap exists between the two walls. In embodiments, at least one flexible lining stretches along the inner wall of insertion portion <NUM>. In alternative embodiments, multiple flexible linings may be utilized. The flexible lining forms a parallel wall inside insertion portion <NUM> such that a gap exists between the parallel wall and the inner wall of insertion portion <NUM>. A pressure pump may be connected to the gap at the proximal end of insertion portion <NUM> that controls pressure of a fluid that fills the gap.

<FIG> illustrate various embodiments of methods that are utilized to seal the flexible lining. In embodiments, the flexible lining may be sealed at the distal end of insertion portion <NUM>. <FIG> illustrates a method of sealing by soldering a flexible lining <NUM>, with the wall of an insertion portion <NUM> at its distal ends <NUM>. In embodiments, flexible lining <NUM> may be punched at its distal ends with insertion portion <NUM>.

<FIG> illustrates another embodiment where a plug <NUM> is utilized in addition to sealing by soldering flexible lining <NUM> with the wall of insertion portion <NUM> at its distal ends <NUM>. Plug <NUM> may be placed between inner walls of flexible lining <NUM> proximal to ends <NUM> to provide additional support to sealed ends <NUM>.

<FIG> illustrates another embodiment where an Ultra Violet (UV) cure adhesive <NUM> is used to seal open ends of flexible lining <NUM>, in addition to plug <NUM>.

<FIG> illustrates yet another embodiment where only UV cure adhesive <NUM> is used to seal open ends of flexible lining <NUM>.

<FIG> illustrates a cross-sectional view of another embodiment of an insertion portion <NUM>. In this embodiment, two or more flexible tubes <NUM> are inserted within insertion portion <NUM>. Sealed ends <NUM> towards the distal ends of each of tubes <NUM> may seal the tubes, such that it carries a volume of water enclosed within tubes <NUM>.

An increase in this volume results directly in an increase of pressure of the water inside the flexible tubes <NUM>, which, in turn, results in an increase in stiffness (or decrease in flexibility) of flexible tubes <NUM>. Conversely, a decrease in this volume results directly in a decrease of pressure of the water inside the flexible tubes <NUM>, which, in turn, results in a decrease in stiffness (or increase in flexibility) of flexible tubes <NUM>. This arrangement also affects the overall flexibility of insertion portion <NUM>, thus enabling control over its maneuverability inside a body cavity.

<FIG> illustrates a cross-sectional view of yet another embodiment of an insertion portion <NUM>. In this embodiment, a flexible tube <NUM> is inserted inside insertion portion <NUM>. Tube <NUM> stretches along one side of an inner wall of insertion portion <NUM>, and may continually stretch along another side of the inner wall of insertion portion <NUM>. Tube <NUM> may bend near the distal end of insertion portion <NUM> to direct its water contents along other sides of its inner wall. In embodiments, flexible tube <NUM> may be placed within insertion portion <NUM> during its extrusion. In alternative embodiments, a guide is used to insert and place flexible tube <NUM> inside insertion portion <NUM>. Once tube <NUM> is placed, the guide may be withdrawn from insertion portion <NUM>.

<FIG> also illustrates a pressure-regulating valve <NUM> that may be used to stop or allow the water within tube <NUM> from flowing back to a pressure pump <NUM> through an inlet <NUM>. In embodiments, once pressure-regulating valve <NUM> is closed, water stops flowing out of tube <NUM>, such that a volume of water is enclosed within tube <NUM>. An increase or decrease in this volume results directly in an increase or decrease of pressure of the water inside tube <NUM>. An increase in this volume results directly in an increase of pressure of the water inside the flexible tube <NUM>, which, in turn, results in an increase in stiffness (or decrease in flexibility) of flexible tube <NUM>. Conversely, a decrease in this volume results directly in a decrease of pressure of the water inside the flexible tube <NUM>, which, in turn, results in a decrease in stiffness (or increase in flexibility) of flexible tube <NUM>. This arrangement also affects the overall flexibility of insertion portion <NUM>, thus enabling control over its maneuverability inside a body cavity.

<FIG> show longitudinal cross-sectional views of a portion of an elongated shaft in an endoscope in accordance with another embodiment. Referring to <FIG>, an insertion portion <NUM> terminates at a tip section <NUM> (shown in <FIG>), which is at the distal end of insertion portion <NUM>. In embodiments, at a proximal end, a handle (not shown) connected to insertion portion <NUM> assists in maneuvering it within the body cavity. The arrangement of these components is described above with reference to <FIG>.

Referring to <FIG>, in embodiments, a flexible tube 1604a extends from the proximal end of insertion portion <NUM> along its length. The illustrated embodiment shows flexible tube 1604a terminating near tip section <NUM>. In alternative embodiments, flexible tube 1604a terminates within the bending section of insertion portion <NUM>. In another embodiment, flexible tube 1604a terminates some distance prior to the bending section of insertion portion <NUM>. In embodiments, flexible tube 1604a is configured to carry gas, such as but not limited to air, or fluid. In embodiments where gas/fluid inflates flexible tube 1604a, the gas/fluid may be sourced from the same supply that feeds the injector channel. Flexible tube 1604a may open into a sealed gas chamber <NUM> near tip section <NUM>, such that the gas carried by tube 1604a is filled inside chamber <NUM>.

An increase or decrease in this volume of the gas within tube 1604a results directly in an increase or decrease of pressure of the gas within chamber <NUM>. An increase in this volume results directly in an increase of pressure of the gas within chamber <NUM>, which, in turn, results in an increase in stiffness (or decrease in flexibility) of insertion portion <NUM> that houses chamber <NUM>. Conversely, a decrease in this volume results directly in a decrease of the pressure of the gas within chamber <NUM>, which, in turn, results in a decrease in stiffness (or increase in flexibility) of insertion portion <NUM> that houses chamber <NUM>.

Referring to <FIG>, an additional flexible tube 1604b is shown. Flexible tube 1604b may be similar in its characteristics and operation to flexible tube 1604a, and may open into a different chamber <NUM> (similar to chamber <NUM>). In embodiments, chamber <NUM> may be located adjacent to chamber <NUM> along the longitudinal axis of insertion portion <NUM>. In another embodiment, chamber <NUM> is located at a predefined distance from chamber <NUM> along the longitudinal axis of insertion portion <NUM>. Chambers <NUM> and <NUM> may be placed concentrically, such that chamber <NUM> is inside chamber <NUM>, and both are aligned inside and along the inner circumferential surface of insertion portion <NUM>.

Referring to <FIG>, another flexible tube 1604c is shown. Flexible tube 1604c may be similar in its characteristics and operation to flexible tubes 1604a and 1604b, and may open into a third chamber <NUM> (similar to chambers <NUM> and <NUM>). In embodiments, chamber <NUM> may be located adjacent to chamber <NUM> along the longitudinal axis of insertion portion <NUM>. In an embodiment, chamber <NUM> may be located at a predefined distance from chamber <NUM> along the longitudinal axis of insertion portion <NUM>. Chambers <NUM>, <NUM>, and <NUM> may be placed concentrically, such that chamber <NUM> is inside chamber <NUM>, which is inside chamber <NUM>, and both all are aligned inside and along the inner circumferential surface of insertion portion <NUM>.

In embodiments, insertion portion <NUM> may include multiple chambers, and the number of chambers may vary. Length of chambers may also vary. In an embodiment, length of the chambers may vary from <NUM> to <NUM>. In other embodiments, the lengths may exceed <NUM>.

Pressure of gas/fluid may be varied separately in all of the chambers described in the above embodiments to variably control stiffness of insertion portion <NUM>.

In embodiments, a pressure pump <NUM> is connected to flexible tubes 1604a, 1604b, and 1604c, at the proximal end of insertion portion <NUM>. In alternative embodiments, pressure pump <NUM> is connected through the handle. Pressure pump <NUM> may control pressure of gas inside each flexible tube 1604a, 1604b, and 1604c. A switch <NUM> or any other external control (such as a button or a knob) may enable an operator to configure pressures within each tube and thus each chamber, to manage stiffness of insertion portion <NUM>. Switch <NUM> may be located on the handle or on a main control unit of the endoscope assembly. The control may adjust the pressure by varying an operating voltage or through a pressure regulator.

Various embodiments of the specification described herein may thus allow flexibility of an insertion portion of an endoscope to vary, thereby increasing ease of navigation through different parts and contours inside a body cavity while solving problems related to looping. The gas and fluid pressure controls provide an additional layer of control over the flexibility of the insertion portion of most available endoscopes.

Alternative embodiments may also be considered that enable control over the flexibility of the insertion portion. These additional alternatives may be in the form of various methods of manufacturing the insertion tube of the insertion portion. Such embodiments enable flexibility of the insertion tube to be controlled on the basis of the manufactured characteristics of the tube. Some embodiments of methods of manufacturing are discussed here.

The immersion method of manufacturing the insertion tube may enable control over rigidity of different areas of the tube. Rigidity of the tube may be controlled by use of different viscosity liquids that construct the base material of a jacket of the tube, which is also known as a sheath. In embodiments, the jacket may be Thermoplastic Polyurethane. Additionally, a portion of the sheath may be of the braided hose type. In embodiments, the hose braid may be manufactured using stainless steel, or a synthetic material, or Kevlar, or any other material known in the art. In embodiments, the type of hose braid used (wire diameter, number of wires per bobbin, number of carriers) also affects the rigidity of the tube. Moreover, flat coils may be used as framework for insertion tubes to provide control over the rigidity of the tube. In embodiments, flat coils may be manufactured using stainless steel, or copper, or any other material known to manufacture flat coils. An advantage of the immersion method is that the insertion tubes manufactured by this method do not require an extra coating.

This method offers advantages when the control over stiffness of the insertion tube is maintained with hose braids and flat spirals. One of the advantages include an improved quality of connection of the insertion tube with its mesh, which is used for the jacket. The improved quality of connection ensure that the sheath remains attached to the tube braid, and thus a widespread form of beads bend in the insertion tube in a tight radius. With a surface treatment of the tubular braid and / or use by the extrusion, a uniform thickness of the casing is achieved. This also results in improved uniformity of stiffness in the rigidity zones. Another advantage is that insertion tubes have a constant stiffness among different manufacturing batches. As a result, the reject rate in production by this method is much lower. Additionally, the tubes manufactured by this method may have a relatively smoother surface. The insertion tubes manufactured by this method also do not require an extra coating.

In this method, flat coils are prepared with the hose braid, and coated with a heat shrink tube, followed by baking in an oven until maximum shrinkage is reached. Variable stiffness may be achieved with this method by differing the quality of the flat coils and of the hose braid.

Various embodiments of the specification described herein may thus allow flexibility of an insertion portion of an endoscope to vary, thereby increasing ease of navigation through different parts and contours inside a body cavity while solving problems related to looping.

Claim 1:
An endoscope assembly comprising an insertion portion that is connected to a handle (<NUM>, <NUM>, <NUM>) at a proximal end of the insertion portion (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) and a bending portion at a distal end of the insertion portion, comprising:
an actuator (<NUM>, <NUM>, <NUM>, <NUM>);
a spring (<NUM>, <NUM>, <NUM>), having a proximal end and a distal end, wherein the proximal end of the spring is connected to the actuator and wherein the actuator activates the spring; and,
a wire (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>), having a proximal end and a distal end, with the proximal end of the wire is connected to the distal end of the spring, wherein the wire stretches along a length of the insertion portion and wherein the distal end of the wire is connected to a proximal end of the bending portion, and wherein the wire stiffens the insertion portion upon activation of the spring; and characterized in that it further comprises a shaft (<NUM>, <NUM>, <NUM>, <NUM>) connecting the spring (<NUM>, <NUM>, <NUM>) and the wire (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>), wherein the shaft has a U-shaped structure comprising:
a first wall connected to distal end of the spring (<NUM>, <NUM>, <NUM>); and
a second wall, parallel to the first wall, connected to the proximal end of the wire (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>); and
wherein the wire (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) enters the shaft (<NUM>, <NUM>, <NUM>, <NUM>) from the external surface of the second wall and is held in place by a stopper (<NUM>) on the other side of the second wall..