Patent ID: 12251132

Referring to the drawings and initially toFIGS.1to9there is illustrated a valve mechanism according to the invention indicated generally by the reference numeral1for releasably coupling to a trocar indicated generally by the reference numeral3, and also according to the invention when coupled to the valve mechanism1. The trocar3is of tubular constructions and comprises an elongated tubular member5of circular transverse cross-section extending between an upstream end6and a downstream end7. The downstream end7of the trocar3may terminate in a metal or plastic sharpened, or non-bladed end. Providing the trocar3with a sharpened downstream end7facilitates entry of the trocar into the abdominal or other cavity through the abdominal wall or other wall of a subject. An elongated instrument bore9also of circular transverse cross-section for accommodating an instrument10, such as, for example, a laparoscope, a surgical instrument or other instrument, a leading end12of which is illustrated inFIGS.1and2, into the abdominal or other cavity, extends through the tubular element5of the trocar3from the upstream end6to the downstream end7. Such trocars as the trocar3will be well known to and understood by those skilled in the art, and further description of the trocar3should not be required.

Turning now to the valve mechanism1, the valve mechanism1comprises a housing15having an instrument bore16of circular transverse cross-section extending therethrough from an upstream end17to a downstream end18, and defining a central longitudinal axis21. The downstream end18of the instrument bore16of the housing15terminates in a flange19extending in a downstream direction from the housing15for coupling the valve mechanism1to the trocar3. The flange19is engageable in the upstream end6of the instrument bore9of the trocar3with the instrument bore16of the valve mechanism1aligned with the instrument bore9of the trocar3.

A valve, in this embodiment of the invention a gate valve20is provided in the housing15for selectively and substantially sealably closing the instrument bore16towards the downstream end18thereof. In this embodiment of the invention the gate valve20comprises a pair of gate elements22located in the housing15, which are slideable into the instrument bore16through gate accommodating slots24formed in the housing15. The gate accommodating slots24extend transversely relative to the instrument bore16for slideably accommodating the gate elements22from an open state illustrated inFIG.2with the gate elements22clear of the instrument bore16providing access through the instrument bore16, to a closed state illustrated inFIG.1with the gate elements22abutting each other substantially centrally in the instrument bore16adjacent the central longitudinal axis21thereof closing the instrument bore16. In this embodiment of the invention each gate element22comprises a plate member25.

An operating means, in this embodiment of the invention, a pair of operating means, namely, a pair of operating elements27are located in the housing15on respective opposite sides of the instrument bore16for urging the gate elements22between the open state and the closed state. Each operating element27is connected directly to the corresponding gate element22. The operating elements27are slideably mounted in respective first guide means, namely, respective first guide bores30which extend transversely in the housing15relative to the central axis21of the instrument bore16thereof on respective opposite sides of the instrument bore16. The operating elements27are slideable in the corresponding first guide bores30between a first state illustrated inFIG.1with the gate elements22of the gate valve20in the closed state, and a second state illustrated inFIG.2with the gate elements22in the open state. A first urging means for urging the gate elements22from the open state to the closed state, in this embodiment of the invention comprises a pair of first resilient urging means provided by respective first compression springs31. Each first compression spring31is located in the corresponding first guide bore30, and acts between the corresponding operating element27and the housing15for resiliently urging that operating element27from the second state to the first state for in turn resiliently urging the corresponding gate element22from the open state to the closed state. The operation of the operating members27for urging the gate elements22between the open and closed state will be described in more detail below.

A detecting means for detecting entry into or movement of an instrument, such as the instrument10, which may be a laparoscope or other instrument or surgical instrument, in the instrument bore16, in this embodiment of the invention, comprises a pair of engagement elements, namely, a pair of engagement members33extending into the instrument bore16from respective opposite sides thereof. The engagement members33are of circular transverse cross-section and are configured for engaging the leading end of an instrument10in the instrument bore16. The engagement members33are moveable in a downstream direction, namely, in the direction of the arrow A, in the instrument bore16by the leading end12of the instrument10as the instrument10is being urged into the instrument bore16from the upstream end17thereof, as will be described below. The operating elements27are responsive to the movement of the engagement members33in the downstream direction for operating the gate elements22of the gate valve20from the closed state to the open state, as will also be described below.

Each engagement member33is carried on a corresponding carrier element35which is slideably located in a corresponding second guide means, namely, a corresponding second guide bore36which extends in the housing15substantially parallel to the central axis21of the instrument bore16, and is spaced apart from the instrument bore16. The second guide bores36are located on respective opposite sides of the instrument bore16corresponding to the sides on which the operating elements27are slideably located in the first guide bores30. Each engagement member33extends from the corresponding carrier element35to the instrument bore16through a corresponding longitudinally extending guide means, namely, a corresponding longitudinal guide slot38. The longitudinal guide slots38extend in the housing15longitudinally along the instrument bore16and radially from the instrument bore16to the corresponding second guide bore36. Each guide slot38extends longitudinally and parallel to the central axis21of the instrument bore16from an upstream end39to a downstream end40, for accommodating longitudinal travel of the corresponding engagement member33parallel to the central axis21of the instrument bore16through a predefined longitudinal distance d from the upstream end39to the downstream end40of the corresponding guide slot38. The predefined distance d of longitudinal travel of the engagement members33in the guide slots38is limited by the upstream ends39and the downstream ends40of the respective guide slots38which act as upstream and downstream limit stops41and43, respectively.

The engagement members33extend from the corresponding carrier elements35into the instrument bore16to engage the leading end12of the instrument10as the instrument10is being urged into the instrument bore16from the upstream end17in a downstream direction. As the instrument10is urged in the downstream direction in the instrument bore16, the leading end12of the instrument10engages the engagement members33, thereby urging the engagement members33downwardly in the guide slots38through the predefined distance d from the upstream end39to the downstream end40thereof, for in turn urging the carrier elements35through the predefined distance d.

Each engagement member33is slideably carried in a carrier bore42in the corresponding carrier element35. The carrier bores42extend into the carrier elements35transversely relative to the central axis21of the instrument bore16, seeFIG.4. A second urging means, in this embodiment of the invention a second resilient urging means comprises a second compression spring44located in the carrier bore42of each carrier element35. Each second compression spring44acts between the corresponding carrier element35and the corresponding engagement member33for urging the engagement member33in a direction transversely relative to the central axis21of the instrument bore16towards the instrument bore16with a distal end45of the corresponding engagement member33extending into the instrument bore16, seeFIG.4.

The distal end45of each engagement member33is of conical shape to form a camming surface48for engaging a peripheral edge46of the leading end12of the instrument10, so that when the engagement member33reaches the downstream limit stop43formed by the downstream end40of the guide slot38, and can travel no further in the downstream direction, the action of the peripheral edge46of the leading end12of the instrument10on the camming surface48urges the engagement member33out of the instrument bore16against the action of the second compression spring44in the corresponding carrier element35. This thereby allows the instrument10to be urged past the engagement members33.

A transmission means, namely, a pair of transmission systems51are provided for transmitting movement of the respective carrier elements35in the second bores36to the corresponding operating elements27, so that as the engagement members33and in turn the carrier elements35are urged in the downstream direction, namely, in the direction of the arrows A, the operating elements27are urged in the directions of the arrows B, from the first state to the second state, for in turn urging the gate elements22of the gate valve20from the closed state to the open state. In this embodiment of the invention each transmission system51comprises a linkage, namely, an elongated link member47. Each link member47is pivotally coupled at one end to the corresponding carrier element35, and at the other end to the corresponding operating element27. A pair of link accommodating slots49extending from the corresponding first guide bores30and from the corresponding second guide bores36into the housing15accommodates the respective link members47and movement thereof as the carrier elements35move in the downstream and upstream directions, namely, in the directions of the arrows A and C respectively, and the operating elements27move between the second and first states.

The first and second compression springs31and44are selected, so that the spring forces exerted by the second compression springs44on the engagement members33and the spring forces exerted by the first compression springs31on the operating elements27, is such that the first compression springs31yield before the second compression springs44yield. This allows the engagement members33to remain extending into the instrument bore16and in engagement with the leading end12of the instrument10as the instrument10is being urged in the downstream direction in the instrument bore16, for in turn urging the engagement members33through the predefined distance d from the upstream limit stop41to the downstream limit stop43. This in turn results in the operating elements27being urged from the first state to the second state in the directions of the arrows B against the action of the first compression springs31, for in turn operating the valve20from the closed state to the open state. When the engagement members33have reached the downstream limit stops43, the action of the leading end12of the instrument10on the camming surfaces48at the distal ends45of the engagement members33results in the second compression springs44yielding. The yielding of the second compression springs44results in the engagement members33being urged out of the instrument bore16against the action of the second compression springs44in the carrier bores42of the carrier elements35by the further downstream movement of the leading end12of the instrument10and its action on the camming surfaces48of the distal ends45of the engagement members33. This, thus, permits the instrument10to pass though the instrument bore16past the engagement members33, and through the valve20now in the open state, and into the instrument bore9of the trocar3.

In this embodiment of the invention a pair of releaseable retaining means is provided for retaining the respective engagement members33in a retained state adjacent the downstream limit stops43when the leading end12of the instrument10has passed the respective engagement members33in the downstream direction, and the engagement members33have been urged out of the instrument bore16and into the guide slots38. In this embodiment of the invention each retaining means comprises a retaining member52extending from a rear face53of the corresponding guide slot38just above the downstream end40thereof for engaging a lug54on the corresponding engagement member33, see in particularFIGS.5to9.

Each retaining member52is located in the corresponding guide slot38spaced apart inwardly from the instrument bore16, so that the retaining members52are only engaged by the lugs54, seeFIGS.7and9, when the engagement members33are urged out of the instrument bore16and fully into the guide slots38by the instrument10, when the engagement members33have reached the downstream limit stops43. Additionally, the relationship between the lugs54and the retaining members52is such that once the leading end12of the instrument10has passed the downstream ends40of the guide slots38travelling in the upstream direction, namely, in the direction of the arrows C, and the engagement members33have been urged by the second compression springs44towards the instrument bore16with the distal ends45thereof extending into the instrument bore16, the lugs54disengage the retaining members52, seeFIGS.6and8.

Once the lugs54have disengaged the corresponding retaining members52, the engagement members33are free to follow the leading end12of the instrument10, under the action of the first compression springs31acting through the operating elements27, the link members47and the carrier elements35, as the instrument is being withdrawn in the upstream direction through the instrument bore16. The engagement members33follow the leading end12of the instrument10under the action of the first compression springs31until the engagement members33abut the upstream limit stops41. At which stage the gate elements22of the gate valve20are in the closed state.

In this embodiment of the invention the engagement members33are slideably keyed in the carrier bores42in the corresponding carrier elements35, in order to prevent rotation of the engagement members33in the carrier bores42of the carrier elements35as they slide therein. This ensures that when the engagement members33are abutting the downstream limit stops43the lugs54are correctly aligned beneath the corresponding retaining members52. Thus as the engagement members33are being urged out of the instrument bore16and into the guide slots38, the lugs54engage beneath the corresponding retaining members52for in turn retaining the engagement members33at the downstream ends40of the guide slots38. The engagement members33remain in the retained state adjacent the downstream ends40of the guide slots38by the engagement action between the lugs54and the retaining members52until the leading end12of the instrument10has cleared the engagement members33on the withdrawal of the instrument10through the instrument bore16. Once the leading end12of the instrument10has cleared the engagement members33, the engagement members33are urged into the instrument bore16by the action of the second springs44, and the lugs54disengage the retaining members52, thereby leaving the engagement members33free to follow the leading end12of the instrument10as the instrument10is being withdrawn from the instrument bore16.

As the engagement members33, and in turn the carrier elements35are being urged through the predefined longitudinal distance d in the direction of the arrow A from the upstream end39to the downstream end40of the guide slots38, the action of the link members47on the corresponding operating elements27urge the operating elements27in the directions of the arrows B against the action of the first compression springs31a sufficient distance to in turn operate the gate elements22of the gate valve20from the closed state to the open state with the gate elements22clear of the instrument bore16.

In this embodiment of the invention the diameter of the instrument bore16in the housing15is approximately 12 mm. The predefined longitudinal distance d defined between the upstream limit stop41of the guide slot38and the downstream limit stop43thereof is approximately 2 mm. It has been found that the travel of the engagement members33and the carrier elements35through the predefined longitudinal distance d of 2 mm is sufficient to urge the operating elements27in the direction of the arrows B through a distance of 6 mm which is half the diameter of the instrument bore16, and thus, is sufficient to operate the gate elements22of the gate valve20between the open and closed states. In this embodiment of the invention as the engagement members33and the carrier elements35are urged downwardly in the direction of the arrow A through the longitudinal distance d of 2 mm, the angle α between the link members47and the corresponding gate elements22reduces from an angle of 66° to 52°.

However, it will be appreciated that the distance d travelled by the engagement members33may be greater or less than 2 mm, and will depend on the ratio of movement required between the engagement members33and the operating elements27. This is determined by the length of the link members47, and the angle α which the link members47make with the corresponding gate elements22when the engagement members33are abutting the upstream limit stops41of the guide slots38. Additionally, the distance d moved by the engagement members33will also be dependent on the diameter of the instrument bore, and also on whether the gate valve is provided as a single gate element gate valve, or a double gate element gate valve as in the gate valve20described with reference to this embodiment of the invention.

A pair of manually operable spindles55are slideably mounted in secondary guide bores57extending upwardly from second guide bores36for manually urging the carrier elements35in the direction of the arrow A, to manually operate the valve20from the closed state to the open state. Each manually operable spindle55extends through the corresponding secondary guide bore57into the corresponding second guide bore36for engaging the corresponding carrier element35. Buttons56on the upper ends of the respective manually operable spindles55are provided for urging the spindles55in the direction of the arrow A for in turn operating the gate elements22of the gate valve20from the closed state to the open state.

In use, the valve mechanism1is connected to a trocar, for example, the trocar3adjacent the upstream end6thereof by engaging the flange19of the housing15in the instrument bore9of the trocar3adjacent the upstream end6thereof. With the flange19of the housing15securely engaged in the upstream end6of the instrument bore9of the trocar3, the valve mechanism1is ready for use. The action of the first compression springs31retains the gate elements22of the gate valve20in the closed state. Additionally, the action of the first compression springs31through the link members47urge the corresponding carrier elements35and in turn the engagement members33in the upstream direction of the arrow C, and retain the engagement members33in engagement with the upstream limit stops41defined by the upstream ends39of the guide slots38. The second compression springs44urge the distal ends45of the engagement members33into the instrument bore16.

On introduction of an instrument10, such as a laparoscope into the instrument bore16of the valve mechanism1, and on urging the instrument10in the downstream direction, namely, the direction of the arrow A, through the instrument bore16, as the leading end12of the instrument10engages the camming surfaces48adjacent the distal ends45of the engagement members33, the engagement members33are urged in the downstream direction from the upstream end39to the downstream end40of the guide slots38through the predefined longitudinal distance d. This results in the operating elements27being urged transversely relative to the instrument bore16in the direction of the arrows B against the action of the first compression spring31from the first to the second states, which in turn operates the gate elements22from the closed state to the open state, thereby opening the gate valve20. Further downstream movement of the instrument10results in the action of the leading end12thereof on the conical camming surfaces48at the distal ends45of the engagement members33urging the engagement members33transversely out of the instrument bore16and into the guide slots38against the action of the second compression springs44, thereby permitting further downstream movement of the instrument10through the instrument bore16, and in turn through the open gate valve20and into the instrument bore9of the trocar3.

Once the engagement members33have been urged from the instrument bore16and into the guide slots38, the lugs54of the engagement members33are engaged by the retaining members52in the guide slots38, and thereby, the engagement members33are retained at the downstream ends40of the guide slots38, while the instrument10is bearing on the distal ends45of the engagement members33. The action of the instrument10bearing on the engagement members33and continuously urging the engagement members33into the guide slots38against the action of the second compression springs44with the engagement members33retained by the retaining members52at the downstream ends40of the guide slots38, retains the valve20in the open state.

On withdrawal of the instrument10, once the leading end12of the instrument10passes the downstream ends40of the guide slots38, the engagement members33are urged into the instrument bore16by the action of the second compression springs44, thereby disengaging the lugs54from the retaining members52. With the lugs54disengaged from the retaining members52, the engagement members33are free to move in the upstream direction in the guide slots38from the downstream ends40to the upstream ends39thereof under the action of the first compression springs31through the operating elements27and the link members47. On further movement of the instrument10in the upstream direction, the engagement members33, and in turn the carrier elements35follow the upstream movement of the leading end12of the instrument10under the action of the first compression springs31, until the engagement members33abut the upstream limit stops41in the guide slots38. As the engagement members33are being urged by the action of the first compression springs31through the operating elements27and the link members47, the operating elements are being urged in the direction of the arrows D, thereby urging the gate elements22of the gate valve20from the open state to the closed state. Accordingly, when the engagement members33have reached the upstream ends39of the guide slots38, the gate elements22of the gate valve20have been urged into the closed state. On removal of the instrument10from the instrument bore16of the valve mechanism1, the instrument bore16is substantially sealed by the gate valve20in the closed state.

Should it be desired to use the valve mechanism on a trocar3to accommodate other instruments, for example, surgical instruments into the trocar3, or should it be desired to remove matter resulting from surgery in an abdominal cavity through the trocar3, the valve20may be opened manually by urging the manually operable spindles55by the buttons56in the direction of the arrow A for in turn urging the carrier elements35in the direction of the arrow A to operate the gate elements22of the gate valve20from the closed state to the open state. Releasing the buttons56of the manually operable spindles55results in the operating members27being urged by the first compression springs31in the direction of the arrow D for operating the gate elements22from the open to the closed state for in turn closing the gate valve20.

Referring now toFIG.10there is illustrated an alternative coupling system for coupling the valve mechanism1to a trocar3. In this embodiment of the invention a releasable securing means is provided for releasably securing the valve mechanism1to a trocar3. The releasable securing means in this embodiment of the invention comprises at least two clasps58which are located on the flange19extending in a downstream direction from the housing15adjacent the downstream end18of the instrument bore16. The clasps58are configured to engage and clamp onto a circumferential flange59extending radially outwardly from and circumferentially around the upstream end6of the trocar3. The clasps58are arranged equi-spaced apart circumferentially around the flange19. Although in this embodiment of the invention only two clasps58have been described, it is envisaged that three clasps58or four clasps58could be provided equi-spaced apart circumferentially around the flange19. It will also be appreciated that any other suitable securing means may be provided for securing the valve mechanism1to the trocar3besides clasps.

Otherwise, the valve mechanism according to this embodiment of the invention is similar to the valve mechanism1described with reference toFIGS.1to9, and its use and operation are likewise similar to the valve mechanism ofFIGS.1to9.

Referring now toFIG.11a valve mechanism according to another embodiment of the invention is illustrated in schematic form, and is indicated generally by the reference numeral60. The valve mechanism60in principle is substantially similar to the valve mechanism1described with reference toFIGS.1to9, and similar components are identified by the same reference numerals. The valve mechanism60comprises a housing61having an instrument bore16extending therethrough from an upstream end17to a downstream end18, in a similar manner as the instrument bore16extends through the housing15of the valve mechanism1.

A valve, which in this embodiment of the invention is also a gate valve20, similar to the gate valve20of the valve mechanism1is located in the housing60and comprises a pair of gate elements22similar to the gate elements22of the valve mechanism1. The gate valve20is operable between a closed state illustrated inFIG.11with the gate elements22substantially sealably closing the instrument bore16, and an open state (not shown) but similar to that of the gate valve20of the valve mechanism1with the gate elements22withdrawn into the housing60from the instrument bore16, leaving the instrument bore16unimpeded.

The housing60adjacent the downstream end18of the instrument bore16terminates in a downwardly extending flange19extending from the housing in a general downstream direction similar to the flange19of the valve mechanism1for similarly engaging in an instrument bore of a trocar adjacent the upstream end thereof.

In this embodiment of the invention the detecting means for detecting an instrument, for example, a laparoscope being entered into the instrument bore16comprises a proximity sensor62located in the housing61adjacent the instrument bore16towards the upstream end17thereof. The proximity sensor62is also configured for detecting the presence of an instrument in the instrument bore16. A probe63extends from the proximity sensor62towards the instrument bore16for detecting an instrument in the instrument bore16.

In this embodiment of the invention the operating means for operating each of the gate elements22from the closed state to the open state comprises a pair of drive means, in this case provided by respective solenoid actuators64located in the housing61for operating the respective gate elements22of the gate valve20from the closed state to the open state. A spindle65extending from each solenoid actuator64is secured to the corresponding gate element22of the gate valve20, and the solenoid actuators64in this embodiment of the invention are configured when activated for urging the respective gate elements22of the gate valve20in the direction of the arrows B from the closed state to the open state. First guide bores67in the housing61accommodate sliding of the spindles65and the gate elements22of the gate valve20between the open and closed states.

A portion66of the spindle65of each solenoid actuator64extends from the opposite end of the solenoid actuator64to the end thereof from which the spindle extends to the corresponding gate element22of the gate valve20. The portion66of the spindle65of each solenoid actuator64is coupled to a first urging means for urging the spindle65of the solenoid actuator64in the direction of the arrow D, for in turn urging the corresponding gate element22of the gate valve20into the closed state when the solenoid actuator64is deactivated. In this embodiment of the invention each first urging means comprises a first compression spring31, which is similar to the first compression spring31of the valve mechanism1, and is located in the housing61. Each first compression spring31acts between the housing and the portion66of the spindle65for urging the spindle65in the direction of the arrow D, to in turn urge the corresponding gate element22of the gate valve20into the closed position.

A control circuit which also includes a power supply is located in the housing61and is illustrated by the block68. The control circuit68reads signals from the proximity sensor62which are indicative of entry of an instrument into the instrument bore16, as well as being indicative of the presence or absence of an instrument in the instrument bore16. The solenoid actuators64are controlled by the control circuit68, so that in response to an instrument being entered into the instrument bore16adjacent the upstream end17thereof or the presence of an instrument in the instrument bore16, the control circuit68operates the solenoid actuators64into the active state for in turn urging the gate elements22of the gate valve20from the closed state to the open state and for maintaining the gate valve20in the open state.

On signals read from the proximity sensor62by the control circuit68being indicative of an instrument having been withdrawn past the probe63in the upstream direction from the instrument bore16, the control circuit68deactivates the solenoid actuators64, and the valve elements22of the gate valve20are urged into the closed state by the action of the first springs31. The control circuit68retains the solenoid actuators64deactivated until the next instrument is detected entering the instrument bore16. While the solenoid actuators64are deactivated by the control circuit68, the gate elements22of the gate valve20are retained in the closed state by the first compression springs31.

In this embodiment of the invention since the gate elements22of the gate valve20are operated from the closed state to the open state by the solenoid actuators64, and are urged from the open state to the closed state by the first compression springs31. Since the detecting means in this embodiment of the invention is provided by a proximity sensor62only one single proximity sensor is required. Indeed, it is also envisaged that in this embodiment of the invention the gate valve may be provided with one single gate element only, which in the closed state would substantially sealably close the instrument bore16, and in the open state would be clear of the instrument bore16. In cases where a single gate element gate valve is provided it will be appreciated that only one solenoid actuator and one first compression spring would be required.

Otherwise, the valve mechanism60and its use is substantially similar to that already described with reference to the valve mechanism1described with reference toFIGS.1to9.

Referring now toFIG.12there is illustrated a valve mechanism according to another embodiment of the invention indicated generally by the reference numeral70. The valve mechanism70is substantially similar to the valve mechanism1described with reference toFIGS.1to9, and similar components are identified by the same reference numerals. The valve mechanism70comprises a housing71and an instrument bore16extending through the housing71. A gate valve20comprising a pair of gate elements22similar to the gate valve20of the valve mechanism1is located in the housing71for selectively closing the instrument bore16. InFIG.12only one half of the housing71is illustrated in cross-section, the other half of the housing71is a mirror image of the cross-sectioned half.

The main difference between the valve mechanism70and the valve mechanism1lies in the detecting means and in the transmission means for transmitting movement of the detecting means to movement of the valve elements22. In this embodiment of the invention the detecting means comprises a pair of engagement members72located in the housing71on respective opposite sides of the instrument bore16, as will be described below, and the transmission means comprises a pair of gear transmission systems73also located in the housing71on respective opposite sides of the instrument bore16for transmitting movement of the engagement members72to the corresponding gate elements22of the gate valve20for operating the gate elements22between the open and the closed states.

Each engagement member72is carried in a corresponding carrier element, which in this embodiment of the invention comprises a cylindrical carrier element75which is rotatably mounted in the housing71on a first shaft76about a first rotational axis77. The first rotational axis77of each carrier element75extends perpendicularly to a plane containing the central axis21defined by the instrument bore16. A guide slot74extending into the housing71from the instrument bore16accommodates the corresponding engagement member72from the corresponding carrier element75into the instrument bore16.

Each engagement member72is slideable in a corresponding carrier bore78radially extending in the carrier element75. A second urging means, in this embodiment of the invention a second compression spring79is located in the carrier bore78of each carrier element75acting between the carrier element75and the engagement member72for resiliently urging the engagement member72into the instrument bore16through the corresponding guide slot74for engaging the leading end12of an instrument10, such as, for example, a laparoscope being urged in a downstream direction into the instrument bore16from the upstream end17thereof. Each guide slot74extends longitudinally a predefined distance d from an upstream end39to a downstream end40which define upstream and downstream limit stops41and43, respectively, for limiting the longitudinal travel of the corresponding engagement member72in the upstream and downstream directions.

Turning now to the gate valve20, an operating means for operating the gate elements22between the open state and closed state comprises respective first gear racks80which are connected to the respective gate elements22of the gate valve20. Each first gear rack80is slideably mounted in the housing71in a first guide means, namely, a first guide bore82which extends transversely relative to the instrument bore16for urging the corresponding gate element22of the gate valve20between the open and closed states.

A first urging means, in this embodiment of the invention a first compression spring31, which is similar to the first compression springs31of the valve mechanism1, is located in the housing71in an extension bore81extending from the first guide bore82, and acts on an end element83located at the end of the first gear rack80opposite to the end thereof to which the first gear rack80is connected to the corresponding gate element22. Each first compression spring31acts between the housing71and the end element83of the corresponding first gear rack80for urging the corresponding gate element22into the closed state.

The gear transmission systems73which will now be described transmits drive between the movement of the respective engagement members72and the corresponding gate elements22. Gear teeth84are provided on each carrier element75over approximately 180° of the carrier element75for cooperating with a corresponding elongated second gear rack85. Each second gear rack85is slideably mounted in a corresponding second guide bore86formed in the housing71and extending parallel to the instrument bore16, so that as the corresponding carrier element75is being rotated in the direction of the arrow A′ by the engagement member72on engagement by the leading end12of the instrument10, the second gear rack85is urged in the second guide bore86upwardly in an upstream direction, namely, in the direction of the arrow C. Each second gear rack85is engageable with a corresponding first intermediate gear87which is mounted fast on a corresponding second shaft88rotatably mounted in the housing71about a second rotational axis89extending parallel to the first rotational axis77of the carrier element75. A second intermediate gear90of diameter greater than the diameter of the first intermediate gear87is also mounted fast on the corresponding second shaft88and is rotatable with the corresponding first intermediate gear87. The second intermediate gear90of each gear transmission system73is in driving engagement with the corresponding first gear rack80, so that on rotation of the second intermediate gear90about the second rotational axis89, the corresponding gate element22of the gate valve20is operated between the open state and the closed state.

Accordingly, on rotation of the carrier elements75in the direction of the arrow A′ resulting from the engagement members72being urged in the downstream direction, namely, in the direction of the arrow A by the leading end12of the instrument10being urged into the instrument bore16in the downstream direction, the second gear racks85are urged in an upstream direction, namely, in the direction of the arrow C, which in turn results in rotation of the first and second intermediate gears87and90in the direction of the arrow C′. This, in turn results in the first gear racks80being urged in the direction of the arrow B, for in turn urging the corresponding gate elements22of the gate valve20into the open state.

As the instrument10is urged further in the downstream direction through the instrument bore16, by the time the leading end12of the instrument10has reached the downstream ends40of the guide slots74in the instrument bore16, the engagement members72have been urged against the downstream limit stops43of the guide slots74, and thereby rotation of the engagement members72terminates. However, at this stage the conical camming surfaces48adjacent the distal ends45of the engagement members72remain projecting slightly into the instrument bore16. On further movement of the instrument10in the downstream direction through the instrument bore16, the leading end12of the instrument10acts on the camming surfaces48at the distal ends45of the engagement members72, thereby, urging the engagement members72into the corresponding carrier bores78in the carrier elements75against the action of the second compression springs79. This, permits the instrument10to be urged through the instrument bore16past the engagement members72. At this stage the gate elements22of the gate valve20are in the open state, and accordingly, the instrument10may then be urged through the instrument bore16of the valve mechanism70and in turn into the instrument bore9of the trocar3.

For so long as the instrument10is located in the instrument bore16the action of the instrument10bearing on the engagement members72, and the action of the second compression springs79urging the engagement members72into engagement with the instrument10results in the engagement members72being retained abutting the downstream limit stops43of the guide slots74, thereby retaining the gate elements22of the gate valve20in the open state.

On withdrawal of the instrument10through the instrument bore16, on the leading end12of the instrument10passing the downstream ends40of the guide slots74, the engagement members72are urged by the second compression springs79into the instrument bore16. As the leading end12of the instrument10is urged further in the instrument bore16in the upstream direction, the spring urging forces of the first compression springs31acting on the first gear racks80result in the first gear racks80being urged in the directions of the arrow D. This in turn results in the engagement members72following the leading end12of the instrument10in the upstream direction, which in turn permits the second compression springs31to urge the corresponding gate elements22from the open state towards the closed state. The engagement members72follow the leading edge12of the instrument10as the instrument10is being withdrawn in the upstream direction through the instrument bore16. Once the engagement members72abut the upstream limit stops41defined by the upstream ends39of the guide slots74, further rotation of the carrier elements75is prevented, and at this stage the corresponding gate elements22of the gate valve20are in the closed state. When the engagement members72are abutting the upstream limit stops41, the distal ends45of the engagement members72project into the instrument bore16for engaging the next instrument or laparoscope being entered into the instrument bore16. While the engagement members72, the carrier elements75and the first and second gear racks80and85and the first and second intermediate gears87and90of the transmission systems73have been illustrated on only one side of the instrument bore16, it will be readily understood by those skilled in the art that engagement members72, carrier elements75and first and second gear racks80and85and first and second intermediate gears87and90of the transmission systems73will be provided in the housing15on respective opposite sides of the instrument bore16for operating the respective gate elements22of the gate valve20.

Manually operable spindles92extend upwardly from the second gear racks85through the second guide bores86to the upstream end17of the housing71. Hand grip knobs93mounted fast on the manually operable spindles92are provided for manually operating the second gear racks85in the direction of the arrow C for in turn manually operating the corresponding gate elements22of the gate valve20into the open state.

Otherwise, the valve mechanism70and its operation is similar to that of the valve mechanism1.

While the embodiments of the valve mechanisms according to the invention have been described with specific types of detecting means and specific types of operating means, any other suitable type of detecting means and operating means may be provided. Needless to say, any other suitable transmission means for transmitting movement of the detecting means to the operating means may be provided besides those described. For example, instead of a transmission means being provided by cooperating gears and gear racks as in the case of the valve mechanism70, a transmission means comprising cooperating gear wheels only could also be provided.

While the angular movement α between the link members47and the corresponding gate elements22of the gate valve20as the engagement members33and in turn the carrier elements35are being moved through the distance d from the upstream ends39to the downstream ends40of the guide slots38has been described as being an angle of 14°, the angle α as the engagement members33are being moved through the predefined distance d from the upstream ends39to the downstream ends40of the guide slots38may vary from 30° to 85° when the gate valve20is in the closed state, and 10° to 60° when the gate valve20is in the open state.

It will also be appreciated that the distance between the downstream ends40of the guide slots38and the gate elements22of the gate valve20will always be sufficient to ensure that the gate valve20is in the fully open state before the instrument, for example, a laparoscope reaches the gate valve20.

While the valves in the embodiments of the invention described have been described as comprising a gate valve, any other suitable valve may be provided. Indeed, it will be appreciated that where the valve is provided as a gate valve, the gate valve may be of the type which would comprise a single gate element only which would operate from one side of the instrument bore16in the open state to the other side of the instrument bore16in the closed state. Further, it is envisaged that the valve may be provided by a ball valve, and in which case, it is envisaged that the ball valve would be rotated through 90° from the open state to the closed state by a gear transmission system which would transmit a linear or a rotational movement of the detecting means to rotational movement of the ball valve.

In the case of a ball valve, or a single gate element gate valve, only one detecting means, for example, one engagement member and one carrier element would be required, and transmission of movement from the engagement member and the carrier element to the valve would be through a single transmission system. In cases where the valve of the valve mechanism70described with reference toFIG.12is replaced with a ball valve, the rotational movement of a single engagement member72about the first rotational axis77would be transmitted to rotational movement of the ball valve through a gearing system, such as a series of gear wheels or a rack and pinion transmission system, or a combination of both.

It is also envisaged that a single detecting means would be sufficient in the case of a gate valve with a pair of gate elements, and in which case suitable transmission means would be provided for transmitting the movement of the single detecting means to the two gate elements of the gate valve.

While the engagement members have been described as being slideable in the corresponding carrier elements35, or the carrier elements75, in certain cases, it is envisaged that the engagement members may be fixed relative to the carrier elements.

While specific transmission systems have been described for transmitting movement from the detecting means to the valve, it will be readily apparent to those skilled in the art that any suitable transmission means may be provided.

Needless to say, any other construction of detecting means besides an engagement member and a carrier element may be provided. It will also of course be appreciated that any other suitable retaining means for retaining the engagement members adjacent the downstream ends of the guide slots38may be provided.

It will be appreciated that while the second gear racks85of the valve mechanism70have been described as being located on the side of the first and second rotational axes77and89remote from the instrument bore16, the second gear racks85may be located on the side of the first and second rotational axes77and89proximal to the instrument bore16. This would have the advantage that when manually operating the valve from the closed to the open state, the knobs93instead of being pulled in the upstream direction of the arrows C would be pushed in the downstream direction, namely, the direction of the arrow A.

While the instrument bore in the valve mechanisms has been described as being of circular transverse cross-section, the instrument bore may be of any suitable cross-section, for example, the instrument bore may be of square cross-section, hexagonal cross-section, or any other suitable transverse cross-section. Needless to say, the instrument bore through the trocar may be of the same or different transverse cross-section to that of the instrument bore extending through the valve mechanism.

It will of course be appreciated that while the various embodiments of the valve mechanism according to the invention have been described with specific components, components from some of the valve mechanisms of the embodiments of the invention may be incorporated into other ones of the valve mechanisms according to the invention.

While the valve mechanisms according to the invention have been described as being configured with an instrument bore for accommodating an instrument, such as a laparoscope or a surgical instrument therethrough, it will be appreciated that the instrument bore may accommodate any surgical or other instruments therethrough, and needless to say, the instrument bore of the valve mechanisms according to the invention may accommodate any instrument, surgical instrument, laparoscope or any other device or element therethrough to the instrument bore of a trocar.