SPECIFICATIONEndoscopeThis invention relates to an improved endoscope and, in particular, to means in the endoscope for providing precise co-ordinatedcontrol over the various functions associatedwith the endoscope.
Among other things, the examination headof an endoscope must be delicately and accurately manoeuvred within a remote body cavity of a patient undergoing examination toavoid discomfort to the patient and in certain .cases to prevent bodily injury. Remote manipulation of the head has heretofor proven to bedifficult because of the complexity of the ,control mechanisms associated with mostendoscopes. Typically, the operator of theendoscope, in order to place the head of theinstrument upon a given target must carry outtwo very distinct and independent operations.
One operation moves the head in a first planewhile the other moves it in a second plane.
The final position of the head is thus theresult of these two operations. Even whenperformed by a skilled highly trained operator,a good deal of time must be taken to placethe examination head on a desired target andthis may be distressing to the patient.
It should be further noted that additionalfunctions, beyond placing the examinationhead upon a given target, ordinarily must beaccomplished during the course of an examination. These additional functions may include, but are not limited to, the movement offluids and/or gases into and out of the examination regions and the insertion and removalof diagnostic tools into the remote body region. The fact that most controls associatedwith endoscopes are usually randomly dispersed on the endoscope in a disorderly manner, makes the co-ordination of these additional functions with the steering control operations extremely difficult. Ordinarily, the operator must use both hands to bring the examination head to a desired position.To initiatean additional operation, the operator mustrelease one or both of the steering controlsthus losing control over this important operation during a critical period of the examination. It often happens tht the instrument becomes misaligned and consequently requiresfurther adjustment that extends the length ofthe examination thus adding to the distressand discomfort of the patient.
By the same token, most endoscopes arestructurally unstable devices wherein many ofthe external components of the endoscope arejust suspended from a relatively flexible probeof the endoscope. Here again, the unstableplatform causes alignment problems andmakes rapid, precise and co-ordinated controlover the various functions of the endoscopedifficult 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; andFigure 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 BritishPatent 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 inthis particular quadrant. At the same timejaws in the opposite quadrant open allowingthe unit to correspondingly expand in theopposite quadrant so that whereupon theprobe is drawn into a relatively smooth, gentlecurve. As can be seen, by manipulating thefour control wires, the examination head canbe smoothly turned to any desired viewingposition.
As illustrated in Fig. 8, each wobble washerin the assembly includes a ring-like bodysection 35. Identical sets of contoured camming 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' apartwhile each set is offset from the other by 90 .
The raised camming surfaces of the lobes aregenerally arcuate in form to allow the washerto rock or pivot easily about each set ofcamming lobes. Holes 37 extend axiallythrough the centre of each lobe for slidablyreceiving one of the control wires therein. Inthe course of assembly, the washers arestrung in bead-like fashion upon the controlwires with a set of camming lobes on thefront face of one washer resting in contactagainst a second set of camming lobes situated on the back face of the next adjacentwasher. The conjoined washers thus form twoopposed jaw members that act in oppositionto each other whereby one set of jaws willopen as the other closes. Similarly, each successive set of jaw members will be turned 90 from the last preceding set.Accordingly aplurality of hinged jaws is established in eachquadrant along the length of the probe. Manipulation of the control wires thus enablesthe operator to manoeuvre the examinationhead to any desired position.
Manoeuvring of the control wires isachieved by means of pulley assemblies 40that are situated within the housing.
The pulley assemblies are driven by meansof a gimbal unit, generally referenced 68,which is controlled by the previously mentioned stick 27. Each pulley assembly contains a pulley wheel 41 having a peripheralgroove 42 about which one of the four controlwires 31 is wound. As illustrated in Figs.
2-5, the pulley wheel of each assembly isrotatably supported with a contoured bracket43 upon a stub shaft that is anchored in thebracket.
Each pulley wheel is rotatably mountedupon a flanged bushing 47 which in turn isslidably received upon the stub shaft 45 witha close sliding fit. An adjusting drum 50 isalso mounted upon the bushing between thebushing flange 51 and an end face 52 of thepulley wheel. Although not shown, a series ofradially extending keys are forced along theperipheral wall of a groove cut in the backface 54 of the drum. The keys are complementary 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 endoscope and also to prevent ambient air frombeing drawn into the cavity when a vacuum isbeing applied thereto.
Secondary or auxiliary valves 104 and 105are also mounted upon the sidewalls of thehousing and upon the connector 20. Thesevalves communicate with secondary fluid lines106 contained within the housing. The secondary fluid lines, as in the case of theprimary lines, are brought into the housing viathe harness and terminate at one of the portscontained in the viewing head. The secondaryvalve can be used to control a number ofdifferent functions such as the introduction ofgases and fluids under pressure into the cavityregion. Although these auxiliary valves are not ,at the immediate fingertip control of the operator, they are nevertheless conveniently located on the housing so that the operator caneasily actuate them with his free hand, that isthe hand which is not gripping the stick 27.
Turning now to Fig. 9, a second example ofa steering mechanism is illustrated whereinthe gimbal unit is replaced by a ball andsocket unit for regulating the movement of thelanyards. Like reference numerals in this embodiment of the invention depict like components in regard to the previously disclosedexample. The base 99 of the control stick issecured to the top of a polished ball 110. Theball, in turn is movably mounted in a twopiece socket 111 which is split along a vertical centreline of the housing. When assembled, the two socket halves hold a split bushing 11 2 centred upon the vertical axis of theball whereby the ball may move freely therein.
A flat control plate 113 is suspended beneath the ball by means of a depending neck114. The plate is perpendicular to the verticalaxis of the stick and, by means of the neck114 is caused to move in direct response tothe movement of the stick. A vertical hole116 passes upwardly through both the plateand the neck 114 to permit the fluid lines 97to pass upwardly into the stick where they areconnected to the valves 95 and 96.
The pulley assemblies 40-40 are mountedin the housing as previously described. Lanyards 76 are passed upwardly therefromthrough openings provided in the mountingwall 65 and the round bead 80 associatedwith each lanyard is seated within a complementary seat formed in the plate. The controlwires are adjusted as noted above thus placing the steering mechanism in a condition toimmediately respond to the positioning of thestick.