GB2070715A - Endoscope - Google Patents

Abstract

An endoscope comprises an examination head 21 mounted in the distal end of an elongated flexible probe 18. The proximal end of the probe 18 is received within a housing 11 having a hand-operated control stick 27 universally movably mounted therein by a gimbal unit 68. The stick 27 is operatively connected to the examination head by control wires that pass through the housing and the probe whereby the examination head responds instantaneously to movement of the stick and follows the stick's motion. Finger-actuated control valves 95-96 are situated upon the stick 27 for regulating the introduction and/or removal of fluids and gases through the probe 18 and the head 21 from the region being examined. A tubular guide having an entrance 100 extends through the housing 11 and the probe 18 to the examination head to enable a diagnostic tool to be directed into and out of the examination region. <IMAGE>

Description

SPECIFICATION Endoscope This invention relates to an improved endos cope and, in particular, to means in the en doscope for providing precise co-ordinated control over the various functions associated with the endoscope.

Among other things, the examination head of an endoscope must be delicately and accu rately manoeuvred within a remote body cav ity of a patient undergoing examination to avoid discomfort to the patient and in certain .cases to prevent bodily injury. Remote manip ulation of the head has heretofor proven to be difficult because of the complexity of the ,control mechanisms associated with most endoscopes. Typically, the operator of the endoscope, in order to place the head of the instrument upon a given target must carry out two very distinct and independent operations.

One operation moves the head in a first plane while the other moves it in a second plane.

The final position of the head is thus the result of these two operations. Even when performed by a skilled highly trained operator, a good deal of time must be taken to place the examination head on a desired target and this may be distressing to the patient.

It should be further noted that additional functions, beyond placing the examination head upon a given target, ordinarily must be accomplished during the course of an exami nation. These additional functions may in clude, but are not limited to, the movement of fluids and/or gases into and out of the exami nation regions and the insertion and removal of diagnostic tools into the remote body re gion. The fact that most controls associated with endoscopes are usually randomly dis persed on the endoscope in a disorderly man ner, makes the co-ordination of these addi tional functions with the steering control oper ations extremely difficult. Ordinarily, the oper ator must use both hands to bring the exami nation head to a desired position.To initiate an additional operation, the operator must release one or both of the steering controls thus losing control over this important opera tion during a critical period of the examina tion. It often happens tht the instrument be comes misaligned and consequently requires further adjustment that extends the length of the examination thus adding to the distress and discomfort of the patient.

By the same token, most endoscopes are structurally unstable devices wherein many of the external components of the endoscope are just suspended from a relatively flexible probe of the endoscope. Here again, the unstable platform causes alignment problems and makes rapid, precise and co-ordinated control over the various functions of the endoscope difficult to carry out.

It is the object of the present invention to provide an improved endoscope and thus improve the safety and comfort of a patient under-going an endoscopic examination.

To this end, according to this invention, an endoscope comprises a viewing head which is movably secured at the distal end of an elongated probe by means of a flexible coupling that allows the head to be moved in two planes which lie perpendicular to each other and contain an axis of the head, wherein the proximal end of the probe is connected to a housing containing a control stick which is mounted in the housing by a swivel joint and extends from the housing, a plurality of flexi ble connecting means passing through the probe and each being connected at one end to the viewing head and at the other end to the stick so that displacement of the stick about the swivel joint produces a corresponding displacement of the viewing head about the axis of the probe.

In one example, the swivel joint comprises a gimbal unit having a pair of gimbal rings adapted to pivot about two mutually perpendicular pivot axes, the control stick being secured to one of said rings, whereby movement of the stick causes the rings to pivot about their respective pivot axes and the connecting means operatively connecting each of the gimbal rings ro the viewing head so that pivotal movement of one of said rings will cause the head to be displaced in one of the said planes and pivotal movement of the other of said rings will cause the head to be displaced in the other of the said planes.

With this arrangement it is possible to exercise extremely sensitive and precise steering control over the examination head of the endoscope. This control may be effected by single-handed operation thereby freeing the other hand of the operator to carry out other tasks.

Two examples of endoscopes in accordance with the invention are illustrated in the accompanying drawings in which:~ Figure 1 is a perspective view of a first example; Figure 2 is a sectional view taken along the line 2-2 in Fig. 1; Figure 3 is a sectional view taken along the line 3-3 in Fig. 2; Figure 4 is an underneath plan view of a control housing of the first example, with a bottom cover removed to show the interior thereof; Figure 5 is an exploded view in perspective showing a portion of a steering or control mechanism forming part of the first example for accurately positioning an examination head thereof; Figure 6 is a perspective view of the distal end of a probe forming part of the first example with portions broken away to show more clearly the component parts thereof;; Figure 7 is a side elevation of a multihinged coupling forming part of the probe and enable the probe to assume a smooth head; Figure 8 is a perspective view of one of a number of irregular-shaped wobble washers which together form the multi-hinged coupling; and Figure 9 is a section corresponding to Fig.

2, but showing a second example of a control housing.

Referring intially to Figs 1-4 there is shown an endoscope, generally referenced 10, that includes a housing 11 that contains the various controls necessary for conducting an endoscopic examination of a remote body cavity of a patient. The endoscope is preferably of the type disclosed in our co-pending British Patent Application Number 2,052,729A which has the capability of displaying a full colour image of the body region under examination upon standard format television. The housing 11 is generally rectangular in shape having a wide base so that it may be securely seated upon a table or other supporting surface. Alternatively, the housing may be provided with its own stand having casters to enable it to be conveniently transported to different locations.

A service harness 12 is joined to the housing by means of an adaptor 14 contained in a sidewall 15 of the housing. The harness is enclosed within a protective sheath 16 and contains electrical leads, further lines and optical fibres needed to service the various endoscope systems. The term fluid as herein used refers to any liquid, vapour or gas that is normally utilized during the course of an endoscopic examination. Although not shown, the leads, lines and fibres are brought out of the sheath to appropriate terminals or couplings to complete the various service circuits.

A thin elongated probe 18 which is made of a flexible tubular material that is conventionally used for this purpose, extends out of the opposite sidewall 19 of the housing through a connector 20. As illustrated in Fig.

1, an examination head 21 is operatively contained within the distal end of the probe.

The examination head contains a viewing window 22 located in an end face 23 thereof.

The window is surrounded by a series of smaller ports 25 that provide both optical and physical access to the body cavity. At least one of the ports houses the terminal end of a fibre bundle used to carry light from a remote illumination source into the cavity. Light is transmitted into the cavity by the bundle to illuminate the region being examined without producing unwanted shadowing. An image is thus created in the objective plane of the viewing system. The image enters the head through the window and is recorded upon a charge coupled device (CCD). The CCD, in turn, converts the optical input to an electrical readout signal that is processed by external equipment so that it can be viewed, or stored in conventional video equipment.

As will be explained in greater detail below, the examination head is manoeurved within a remote body cavity in response to the movement of a hand-held control stick 27 that extends upwardly from the top wall of the housing. The stick is connected to the head by means of control wires that extend therebetween through the housing and the probe and which act through a steering control mechanism that is arranged so that the motion described by the examination head is an analogue of the motion imparted to the free end of the stick. Accordingly, an operator watching the television display of the region under examination has only to move the stick towards any desired target on the screen to produce an immediate and precise movement of the head to centre the optical axis of the viewing system upon the target.The stick can also be moved in a circular manner to scan the examination head around the remote body cavity thereby providing wide visual coverage of the region being examined.

As best illustrated in Figs. 6, 7 and 8, control wires are connected to the examination head through a multi-hinged coupling 26.

The coupling controls the curvature of the head to ensure that the probe head adopts a gentle, smooth curve as the head is manipulated within the cavity.

Any severe bending of the probe could possibly cause injury to the patient. The coupling is situated within the probe directly behind the examination head and can be secured thereto by any suitable means. The coupling is cylindrical in form and contains an annular base section 28 which abuts the head, an annular end cap section 29 at the rear of the probe and a series of irregularshaped wobble washers 30-30 generally coaxially aligned between the base and the end cap sections. Four control wires 31 are each anchored at one end in the base section 28 and extend rearwardly through openings provided in the base section at the periphery thereof. The wires are circumferentially spaced around the section 28 at 90 intervals. Flexi ble hollow wound cables 33 are secured by buttwelding to the front plate 34 of the end cap section of the coupling and receive the control wires 31 slidably therein. The cables pass back through the probe into the housing and serve to prevent the control wires 31 from becoming entangled within the probe.

The wobble washers are stacked between the base section and the end cap section to form a plurality of hinged jaws located along the length of the cylinder. A plurality of jaw elements are adapted to open and close in each of the four quadrants defined by the control wires. Accordingly, when one of the wires is drawn inwardly towards the housing, the jaws in this particular quadrant are caused to close producing a shortening of the unit in this particular quadrant. At the same time jaws in the opposite quadrant open allowing the unit to correspondingly expand in the opposite quadrant so that whereupon the probe is drawn into a relatively smooth, gentle curve. As can be seen, by manipulating the four control wires, the examination head can be smoothly turned to any desired viewing position.

As illustrated in Fig. 8, each wobble washer in the assembly includes a ring-like body section 35. Identical sets of contoured camm ing lobes 36-36 are situated on the front end face and back end face of the body section.

The lobes in each set are located 1 80' apart while each set is offset from the other by 90 .

The raised camming surfaces of the lobes are generally arcuate in form to allow the washer to rock or pivot easily about each set of camming lobes. Holes 37 extend axially through the centre of each lobe for slidably receiving one of the control wires therein. In the course of assembly, the washers are strung in bead-like fashion upon the control wires with a set of camming lobes on the front face of one washer resting in contact against a second set of camming lobes situ ated on the back face of the next adjacent washer. The conjoined washers thus form two opposed jaw members that act in opposition to each other whereby one set of jaws will open as the other closes. Similarly, each suc cessive set of jaw members will be turned 90 from the last preceding set.Accordingly a plurality of hinged jaws is established in each quadrant along the length of the probe. Ma nipulation of the control wires thus enables the operator to manoeuvre the examination head to any desired position.

Manoeuvring of the control wires is achieved by means of pulley assemblies 40 that are situated within the housing.

The pulley assemblies are driven by means of a gimbal unit, generally referenced 68, which is controlled by the previously men tioned stick 27. Each pulley assembly con tains a pulley wheel 41 having a peripheral groove 42 about which one of the four control wires 31 is wound. As illustrated in Figs.

2-5, the pulley wheel of each assembly is rotatably supported with a contoured bracket 43 upon a stub shaft that is anchored in the bracket.

Each pulley wheel is rotatably mounted upon a flanged bushing 47 which in turn is slidably received upon the stub shaft 45 with a close sliding fit. An adjusting drum 50 is also mounted upon the bushing between the bushing flange 51 and an end face 52 of the pulley wheel. Although not shown, a series of radially extending keys are forced along the peripheral wall of a groove cut in the back face 54 of the drum. The keys are comple mentary to a series of keyways 53 cut in the flange of the bushing and, when assembled, are seated therein so that the drum turns with the bushing. A plurality of equally-spaced Vshaped teeth 55 are generated in the front face of the drum. The teeth are adapted to mate with complementary teeth 56 cut into the back face of the adjacent pulley wheel. A nut 57 is threaded on to the end of the bushing and serves to hold the pulley wheel thereon.The wheel subassembly, in turn, is slipped over the shaft and is retained thereon by means of a spring clip 46.

A pair of arcuate-shaped slots 58 are cut or otherwise formed in the front face of each pulley wheel with the slots extending between the peripheral groove of the wheel and circular recess 59. A small circular bead is fixed to the end of each control wire 31 and the bead is seated within the recess 59 to secure the wire to the wheel. With the bead seated within one of the two recesses, the trailing end of the wire is brought into the companion slot and trained over the pulley so that the wire can be wound upon the wheel.

A retainer 62 having a C-shaped opening therein is secured to the bottom surface of the pulley bracket 43 by means of screws which also serve to locate accurately the opening adjacent to the peripheral groove of the pulley wheel. The proximal end of the control wire cable 33 is slipped into the opening and is secured in place by means of a plate 63 that is secured over the opening. As can be seen, each cable 33 is securely retained at one end in one of the pulley assemblies and at the other end in the multi-hinged coupling. Accordingly, the control wire contained therein is able to move freely into and out of the probe in response to the movement of the pulley wheel.

The bracket 43 which supports each of the pulley assemblies is secured to the bottom surface of a mounting wall 65 which is fixed in a horizontal position to the sidewalls of the housing by screws 66 (Fig. 4). The brackets are circumferentially spaced around the vertical centreline of the housing and are arranged to support the pully assemblies so that the control wires trained over the wheels are able to move freely in and out of the probe.

As noted, the four pulley assemblies are driven by a gimbal unit 68. The gimbal unit is made up of an outer gimbal ring 69 and an inner gimbal ring 70. The inner gimbal ring is in the form of a hemisphere. In practice, the outer ring is pivotally mounted between two upraised arms 71 of the mounting plate by means of two coaxially aligned pivot pins 72.

The inner ring is suspended within the outer ring by means of a second set of coaxially aligned pivot pins 73 that are aligned perpendicular to the first set. The inner gimbal ring is secured to a base 74 of the control stick 27 so that the stick is coaxially aligned with the minor axis of the hemisphere. The stick is provided with a contoured hollow hand grip 75 and extends upwardly through an opening in the top wall of the housing to a position where it can be conveniently gripped by the operator of the endoscope. Manipulation of the control stick will cause the gimbal rings to be pivoted about their respective pivot pins in a predeterminable manner.

Referring more specifically to Figs. 3 and 5, the adjusting drum of each pulley assembly is connected to one of the gimbal rings by a lanyard 76 that passes upwardly through the mounting plate via hole furnished therein. The lanyard has at one end a square bead 79 which is fitted into a square opening contained in an embossment 77 (Fig. 3) that extends radially from the outer wall of the drum. The opposite end of the lanyard has a round bead 80 which is fixed thereto and is seated within one of the complementary recesses 81 and 82 formed in the gimbal rings.

Tabs 83 are secured to the inner gimbal ring 90 from each pivot. The tabs are provided with contoured recesses that are designed to receive the round ball of a lanyard therein.

The lanyard 76, which is offset some distance from the centreline of the pulley wheel, provides a velocity ratio to the system that enables the control wires to be more easily manipulated by the stick. Accordingly, the lanyard is made of relatively strong braided wire that prevents breakage in the critical area thereby ensuring dependable and lengthy operation of the steering control mechanism.

Two opposed pulley assemblies are connected by the lanyards 76 to the inner gimbal ring while the other two opposed assemblies are similarly attached to the outer gimbal ring.

The pulley wheels are orientated with the control wires 31 so that the examination head will faithfully follow the stick 27 as it is moved within the housing to describe an analogue of the stick's motion. Pushing the stick forward will cause the head to point upwardly while pulling back upon the stick will move the head downwardly. Similarly, moving the stick either to the right or the left of centre produces a corresponding movement of the examination head. By use of the stick, the operator can either scan the head across the region being examined or, alternatively, place the head directly upon a target. A railing 85 is supported above the top wall of the housing 11 by stanchions 88-88. The railing encircles the control stick and provides a stable rest for the operator's hand and arm.

The railing also provides a reference that corresponds to the television presentation. By a sense of feel, the operator can quickly orientate the stick with reference to the display and make extremely fine adjustments to the head quickly and accurately.

Referring now to Figs. 1, 2 and 3, the stick 27 passes upwardly through a collar 89 having a screw threaded annulus 90 secured thereto by screw means (not shown). The annulus is screwed into the top wall of the housing and contains a friction ring 91 that is fitted into a complementary groove formed with the inner wall of the annulus opening.

The collar is equipped with a pair of opposed thumb tabs 92 supported upon the ends of radially extending arms 93. The tabs are raised to an elevation such that the operator who is manoeuvring the stick, can engage at least one of the tabs with the fingers of his stick hand and turn the collar with the housing. By turning the collar in one direction, the friction ring can be brought into biasing contact against the hemisphere-shaped body of the inner ring. Sufficient leverage is provided through the arm mechanisms to enable the friction ring to securely lock the gimbal unit 68 in a desired position thereby holding the viewing head aimed at a specific target. Simply turning the collar in the opposite direction will release the biasing force applied to the gimbal unit 68.

A pair of finger-actuated valves, 95 and 96 are strategically positioned upon the stick and are operable to initiate two primary operations related to the endoscopic examination. As a consequence these valves shall be referred to as the primary valves. Each valve is connected into a fluid line 97 that is brought into the housing via the harness and which terminates at one of the ports situated in the front face of the viewing head. The first primary valve is adapted to introduce air and water into the cavity region which can be used to cleanse the viewing window and the cavity region.

The second primary valve is operable to draw a vacuum at one of the ports whereupon fluid within the cavity region is quickly withdrawn therefrom. It should be understood, however, that the primary valves can be adapted to control a wide variety of similar functions without departing from the scope of the present invention.

The fluid lines serviced by the primary valves are diverted from the harness upwardly through a soft rubber gromet 98 centred in the mounting plate directly below the stick.

The base section of the stick contains a central opening 99 that opens into the upper grip section thereby providing the fluid lines with access to the valves without interfering with or otherwise impeding the gimbal operation, An instrument access 100 is located in the harness retainer 14. The access contains a screw threaded section 101 that can be removed for cleaning. This section opens into a conduit 102 leading through the probe and terminating at one of the ports positioned at the end face of the probe. Accordingly, a small instrument can be guided through the conduit into the body cavity to take tissue samples or the like and then be retracted without disturbing the other system components.The screw threaded section has seals to prevent contaminants from entering the en doscope and also to prevent ambient air from being drawn into the cavity when a vacuum is being applied thereto.

Secondary or auxiliary valves 104 and 105 are also mounted upon the sidewalls of the housing and upon the connector 20. These valves communicate with secondary fluid lines 106 contained within the housing. The sec ondary fluid lines, as in the case of the primary lines, are brought into the housing via the harness and terminate at one of the ports contained in the viewing head. The secondary valve can be used to control a number of different functions such as the introduction of gases and fluids under pressure into the cavity region. Although these auxiliary valves are not ,at the immediate fingertip control of the oper ator, they are nevertheless conveniently lo cated on the housing so that the operator can easily actuate them with his free hand, that is the hand which is not gripping the stick 27.

Turning now to Fig. 9, a second example of a steering mechanism is illustrated wherein the gimbal unit is replaced by a ball and socket unit for regulating the movement of the lanyards. Like reference numerals in this em bodiment of the invention depict like compo nents in regard to the previously disclosed example. The base 99 of the control stick is secured to the top of a polished ball 110. The ball, in turn is movably mounted in a two piece socket 111 which is split along a verti cal centreline of the housing. When assem bled, the two socket halves hold a split bush ing 11 2 centred upon the vertical axis of the ball whereby the ball may move freely therein.

A flat control plate 113 is suspended be neath the ball by means of a depending neck 114. The plate is perpendicular to the vertical axis of the stick and, by means of the neck 114 is caused to move in direct response to the movement of the stick. A vertical hole 116 passes upwardly through both the plate and the neck 114 to permit the fluid lines 97 to pass upwardly into the stick where they are connected to the valves 95 and 96.

The pulley assemblies 40-40 are mounted in the housing as previously described. Lany ards 76 are passed upwardly therefrom through openings provided in the mounting wall 65 and the round bead 80 associated with each lanyard is seated within a comple mentary seat formed in the plate. The control wires are adjusted as noted above thus plac ing the steering mechanism in a condition to immediately respond to the positioning of the stick.

Claims (10)

1. An endoscope comprising a viewing head which is movably secured at the distal end of an elongated probe by means of a flexible coupling that allows the head to be moved in two planes which lie perpendicular to each other and contain an axis of the head, wherein the proximal end of the probe is connected to a housing containing a control stick which is mounted in the housing by a swivel joint and extends from the housing, a plurality of flexible connecting means passing through the probe and each being connected at one end to the viewing head and at the other end to the stick so that displacement of the stick about the swivel joint produces a corresponding displacement of the viewing head about the axis of the probe.

2. An endoscope according to Claim 1, in which the swivel joint comprises a gimbal unit having a pair of gimbal rings adapted to pivot about two mutually perpendicular pivot axes, the control stick being secured to one of said rings, whereby movement of the stick causes the rings to pivot about their respective pivot axes and the connecting means operatively connecting each of the gimbal rings to the viewing head so that pivotal movement of one of said rings will cause the head to be displaced in one of the said planes and pivotal movement of the other of said rings will cause the head to be displaced in the other of said planes.

3. An endoscope according to Claim 1 or Claim 2, wherein the stick is connected to a plurality of pulley units and the flexible connecting means are wound one around each of the pulley units.

4. An endoscope according to Claim 3, in which a pair of the pulley units are connected to each gimbal ring in such a way that the pulleys in each pair of the pulley units are turned in opposite directions as the corresponding gimbal ring is pivoted about its axis and the flexible connecting means wound around one of the pulleys is partly unwound and the other flexible connector means is wound further around its pulley.

5. An endoscope according to any one of the preceding Claims, wherein the flexible connecting means are equally spaced around the periphery of the viewing head.

6. An endoscope according to Claim 2 or any one of Claims 3 to 5 when dependent on Claim 2, in which the gimbal unit includes an inner ring containing a part-spherical member mounted thereon and adjustable friction means acting upon the spherical member for exerting a holding friction force on the gimbal unit.

7. An endoscope according to Claim 6, wherein the stick is fixed to the part-spherical member.

8. An endoscope according to any one of the preceding Claims, in which the housing carries a hand rest that encircles the stick.

9. An endoscope according to Claim 3 or any one of Claims 5 to 8 when dependent on Claim 3, in which the stick is connected to each of the pulley units by a lanyard which has a higher tensile strength than each of the flexible connecting means.

10. An endoscope according to Claim 1, substantially as described with reference to Figs. 1 to 8 or Fig. 9 of the accompanying drawings.