NO180660B - Shooting for optical conductors, especially for underwater use - Google Patents

Description

This invention relates to a joint for connecting the ends of two optical conductors.

More specifically, the invention relates to a joint for connecting two optical fiber lines with one or more fibers, of the type that comprises two complementary connection elements, each with a housing which forms a space in its interior for receiving the end of the optical conductor and which in its one axial end is open in the direction towards the front connecting or coupling end of the housing.

A number of solutions are known for connection between two optical conductors and which can perform an appropriate connection, in particular by ensuring that the necessary positional tolerances are observed between the two conductor ends, as these tolerances must be observed in order to maintain a good signal transmission through the joint.

Thus, it is known to equip the end of each of the waveguides with an aspherical lens which magnifies the light beam which is formed at the end of the guide, this is particularly shown and described in the patent document WO-A-8600422. An enlargement of the light beam from the end of the optical conductor on both sides of the joint allows the transmission between two parallel front surfaces in the joint to be maintained without relative deviation. The positioning of the enveloping contour for the two contact surfaces can be secured with a joint of the male/female type and optionally supplemented by centering devices with balls. However, it is of particular importance that the optical contact surfaces, each e.g. represented by a glass egg with parallel surfaces, are scrupulously clean to avoid reducing the quality of the optical transmission.

This problem with the cleanliness of the ends of the light or waveguides to be connected is particularly important for joints that are to be used underwater and which are often used in data transmission networks for petroleum installations on the seabed at great depths.

When an optical cable is branched and one thinks about the problems with intervention and maintenance in an underwater environment, one will understand that the ends of optical conductors, especially their parallel glass egg surfaces, will be exposed to the marine environment in an intervention situation, and this is unfortunate, since the water contains particles in suspension which can settle on the surfaces and reduce the optical transmission quality.

In order to avoid these problems, WO-A-8602173 proposes a joint of the type mentioned at the outset and where each connection element has a closing device for the inner space of the housing to close this upon disconnection.

According to this patent document, the closure devices consist of an elastically deformable membrane that is pierced in the middle and at the connection is penetrated by a plug element that is connected to an optical fiber in one of the connection elements. The reliability of such a construction is, however, difficult to control, especially when disconnecting, since the mechanism is exposed to friction between the membrane and the plug element, and furthermore it is difficult to get a sufficiently accurate adjustment of the different return springs that are used.

From US A 4 913 514, a hermaphroditic type fiber optic joint is known for connecting light conductors, and whose special features correspond to what appears in the introduction of the first of the set patent claims, according to the description that follows below. Each closing device in the joint thus has a displaceable shutter designed as a damper and controlled by a rod fixed in a compression spring device. The introduction of the rod into a complementary recording space, however, requires precise angular adjustment of the joint's two contact parts, and the joint is also not particularly well suited for marine environments.

Similar fiber optic joints or coupling sets are also known from US 4 887 883 and NO 854758 which include mechanisms for pressure equalization and membrane protection of the coupling elements.

The present invention builds on the known technique and seeks to avoid the disadvantages that known joints have shown, by offering a joint of a similar type, but which is characterized in particular by the fact that each damper is arranged to be rotatable about an axis normally on the central part of the connecting elements, longitudinal central axis, between a first angular end position for closing the space in a sealing manner, and a second retracted angular end position, that each movable mechanism for displacing its respective damper comprises a tubular element at the front end of which the damper is rotatably fixed, the tubular element being movable sliding in its respective housing between a first axially advanced position relative to the housing and spring-loaded against this position by its respective spring device, and a second axially retracted end position relative to the housing, that each movable mechanism for displacing the rotatable damper comprises means arranged between the damper and the housing to cause rotation of the damper t between its closed and retracted angular positions under the action of the corresponding axial displacement of the movable mechanism between its advanced and retracted positions, and that each of the control means for closing the second connecting element is formed by the front outer surface of the respective tubular element, which front outer surfaces are arranged for mutual cooperation during the joining of the two connecting elements to cause longitudinal displacement of each of the tubular elements towards its axially retracted position, for which position the associated damper is brought to its retracted angular position.

Other characteristic features and particularities of the invention will be apparent from the description and the non-independent patent claims 2-10, the joint in particular being such that: the mechanisms for displacing the dampers comprise at least one control cam arranged on them and in cooperation with at least one fixed cam which is connected to the housing and which extends parallel to the axis of rotation of the damper,

that the shutter is designed as a spherical element with an internal recess that is bounded by two parallel side surfaces that are normal to the shutter's axis of rotation and between which an extension in the housing extends, the extension comprising two cams that face each other, align and are arranged to recorded in two parallel and opposite grooves formed by the ridges in the side surfaces,

that the spherical outer surface of the shutter is arranged to abut against complementary inner surfaces of the tubular element,

that the tubular element is arranged to slide in relation to the housing and whose front end defines an opening with which the closing valve cooperates,

that the inner surfaces are formed on the inner surface of an internal radial projection in the front part of the tubular element which delimits the opening, and that the outer spherical surface of the closing valve rests resiliently against the inner surfaces as a result of the spring action from a helical compression spring as on the one side

abuts against the outer surface of the closing valve and with its other end abuts against a radially opposed and internal abutment in the housing to guide the tubular element under spring force towards its first position,

that the end of the light guide has a first connection element and is axially immobilized in relation to the housing for the first connection element, that the end of the light guide for the second connection element is arranged to be slidable in relation to the housing for this second element, between a retracted position behind the opening of the room and an advanced coupled position in contact with the end of the first light guide,

that the optical fiber connected to the second connecting element is fixed in a sleeve that can slide in relation to the housing, that a locking mechanism is arranged for locking the retracted position of the sleeve in relation to the housing,

that the room is sealed in the closed position of the closing valve, and that each connecting element includes elements for maintaining the internal pressure in the room, at a pressure value that corresponds to the ambient pressure, and

that the end of each of the light guides has a device to enlarge the outgoing light beam from the light guide, as the light transmission is carried out between two parallel optical contact surfaces.

By providing a closing device equipping each connecting element, it is thus possible to completely protect the optical contact surfaces of the ends of the light guides when the connecting elements are not connected and to keep the ends permanently in a space which, in the case of an underwater joint, contains an indicator liquid of a certain type and which is kept isolated from the marine environment during the disconnection.

Now a specific embodiment of the joint of the invention will be reviewed, referring to the associated drawings, where fig. 1 shows an axial section of a typical such joint whose two connecting elements are shown in the disconnected position, fig. 2 shows a detail on a larger scale of the shutter and the mechanism which ensures its rotation, fig. 3 shows a cross-section according to 3 - 3 in fig. 2, fig. 4 shows the shutter from the underside, and fig. 5-8 show in a similar way as fig. 1 the different relative positions between the two connection elements during a connection operation.

The joint 10 shown in fig. 1 consists, as mentioned, of two connecting elements 12A and 12B with a common central central axis X-X.

Each connecting element has for the most important main components a rotational symmetry about the central axis X-X.

The connection element 12A is shown in the form of a base element whose housing 14A is mounted on a support frame 16, while the other connection element 12B is shown in the form of a movable plug element at the end of an optical cable 18.

The function of the joint 10 is to ensure the transmission of optical waves or light signals between a first optical conductor or light conductor 20A and a second corresponding light conductor 20B.

The ends 22A, 22B of each of the light guides is designed as a special optical device such as an aspherical lens (here not shown) which terminates in an end surface 24A, 24B normal to the main optical transmission axis which in turn runs mainly parallel to the central axis X-X.

In the first connection element 12A, the optical device 22A is fixed to the interior of the housing 14A by means of an internal sleeve 26A whose rear radial edge 28A is fixed by means of screws 30A to the rear surface 32A of the housing 14A.

A tight gasket 34A ensures a seal between the sleeve 26A and the housing 14A.

The main part of the optical device 22A is screwed to the interior of the sleeve 26A, and a tight gasket 36A is provided between the outer surface of the device 22A and the inner bore of the sleeve 26A which receives the device.

The sleeve 26A extends axially towards the front connecting or coupling end of the housing 14A via an extension 38A whose function will be explained in more detail later. It should be noted here that it is attached to the housing 14A, i.e. that it is immobilized against rotation and axially in relation to this.

The internal bore 40A in the housing and which is arranged to receive the fixed sleeve 26A likewise receives a sliding tubular element 42A which forms a control mechanism for a closing valve 44A whose function is to seal the internal space 46A which is defined in the housing 14A.

The element 42A has at its rear end a radial outer projection 48A which determines the element's first axial position shown in fig. 1 in relation to house 14A.

This same radial shoulder 48A is intended to cooperate via its rear facing radial surface with a radially opposite shoulder 50A on the sleeve 26A, to establish a second axial position for the tubular element 42A in relation to the housing 14A, which will be explained in more detail later in the description .

The tubular element 42A is arranged slidingly and sealingly in the bore 41A in a part 41A of the bore 40A in the housing 14A and is terminated at the front by an internal radial projection 52A which on the one hand delimits a front circular opening 54A and on the other hand a front outer surface 56A which normally stands on the central axis X-X.

Now the closing valve 44A will first be described, and reference is then made in particular to fig. 2-4.

The shutter 44A has a generally spherical external shape and an internal recess 58A which is delimited by two parallel side surfaces 60A which face each other and a front half-cylindrical surface 62A. In the closed position shown in fig. 1 has the surface 62A and its generatrix mainly position normally on the central axis X-X which in turn runs parallel to the side surfaces 60A. The front part 64A of the closing damper 44A is mainly in the form of a massive ball cap whose outer surface 66A is in contact with the inner surface 68A of the radial internal shoulder 52A in the tubular element 42A.

A sealing gasket 70A is arranged against the inner surface 68A, as this forms a control surface for rotary movement of the closing valve 44A. Each of the side surfaces 60A has an inclined cam 72A.

The fixed extension 68A extends axially between the side surfaces 60A of the recess 58A, and the end is equipped with two coaxial and opposite lugs 74A which are received in the grooves formed by the combs 72A.

The cooperation between the cams 74A and the cams 72A is, in addition to allowing the closing valve 44A to rotate about an axis which runs mainly normal to the central axis X-X, also immobilization with regard to rotation of the closing valve 44A in relation to the central axis.

The outer spherical surface of the closing damper is kept in contact with the inner surface 68A which serves as a control surface, by means of a helical compression spring 76A inserted into the interior of the tubular element 42A.

The spring 76A abuts on its one side against the fixed opposite shoulder 50A in the sleeve 26A in the housing 14A and with its opposite end against the outer spherical surface via an annular shoe 78A. In addition to its function of bringing the spherical surface of the closing damper toward the guiding inner surface 68A and allowing rotation of the damper, the compression spring 76A also performs steering of the tubular member 42A toward its first position shown in FIG. 1. The front part of the housing 14A terminates in an axial and cylindrical extension 80A whose internal profile is conical to facilitate the guidance of the second connecting element 12B of the plug type during the mating.

The housing 14A likewise has an external and rigid cylindrical collar 82A which is pierced by a series of radial holes 84A and is itself enclosed by a deformable, tight elastic member 86A, and a radial hole 88A which brings the space 46A into communication with a pressure equalization chamber 90A which is defined inside of the element 86A in the form of a membrane.

For the position shown in fig. 1, it should be noted that the space 46A is completely sealed, and its internal pressure is maintained at a value that is determined in advance and is at least equal to the pressure of the external environment surrounding the membrane 8 6A.

Now the second connection element which is a socket element 12B will be briefly described, the elements and components in this being the same or similar to those described for the first element, the plug element 12A, the only difference being that the reference numbers instead have additional the letter B.

In the embodiment shown, the housing 14B is made in one piece with the extension 38B and the internal sleeve 26B for receiving the optical device 22B mounted slidingly in the internal bore 40B in the housing 14B.

The face of the forward portion 64B of the shutter 44B has a concave, spherical outer surface 66B which is complementary to the corresponding convex outer surface 66A of the base member 12A.

The tubular and sliding element 42B which serves for control is mounted in the plug element in a sliding and watertight manner on the outside of the housing 14B. In this way, the rear outer portion 43B of the element 42B is sealingly attached to a sleeve 92B which is slidable relative to the cylindrical outer surface of the housing 14B and which is terminated by an internal radial shoulder 48B which cooperates with the rear outer surface 32B of the housing 14B to secure it first position of element 42B shown in fig. 1.

The inner sleeve 26B is shown in fig. 1 in its first axial and retracted position relative to housing 14B in which it is held in place by locking balls 94B. These, in turn, are received in an annular groove 96B in the outer cylindrical surface of the sleeve 26B.

The equilibrium element 86B for pressure equalization is here arranged axially in relation to the rear part 27B of the sleeve 26, and the whole is protected by a cylindrical jacket 98B which can slide on the outer cylindrical surface 100B of the sleeve 92B.

The rear part of the mantle 98B is formed by a plug 102B which occupies the rear part 27B of the sleeve 26B in a sealing manner and axially rests against a radial shoulder 104B on this.

The inner diameter of the cylindrical wall of the mantle 98B is made so that it can slide on the outer cylindrical surface 100B of the sleeve 92B as well as in relation to the cylindrical outer surface of the tubular element 42B.

Now the operation of the joint 10 will be described by first proceeding from the disconnected position shown in fig. 1 and where the connection direction is further indicated by the arrow F.

Starting from the first disconnected position where the two rooms 46A and 46B are both closed tightly by the closing valves 44A and 44B, the operator performs an axial displacement of the element 12B in relation to the corresponding base element 12A until the surfaces 56A and 56B of the tubular elements lie in mutual contact as shown in fig. 5.

This first movement is facilitated by the conical shape of the collar 82A on the housing 14A.

In this first position shown in fig. 5, the convex outer surface 66a and the concave outer surface 66B are thus in mutual contact with each other, and the arrangement between them has the effect of displacing the surrounding liquid, even though the connecting elements 12A and 12B are not yet in contact with each other.

Based on the determined spring tension of the springs and the frictional forces against the sealing gaskets, a continued bringing together of the plug element against the base element can lead to an axial sliding towards the second position of the tubular element 42A. This next position is illustrated in fig. 6, and it should be noted that the closing valve 44A is here rotated 90° in the clockwise direction to fully release the front opening 54A, the front surface 62A being positioned so that its generatrices run substantially parallel to the center axis X-X.

In this position, the planar end surface 24A of the optical device 22A will be directly opposite the circular opening 54A.

The rotation of the closing damper 44A naturally causes the cams 74A to move, and these cooperate with the cams 72A to effect rotation of the damper.

In this position, which is an intermediate position and is shown in fig. 6, the components in the first connecting element 12A take their definitive end position for the connection.

It is interesting to note that even in a case where a small drop of purified water comes to lie between the surfaces 66A and 66B, no impurity will be able to penetrate into the space 46A thanks to the presence of the element 86A in the form of a membrane and the penetration of the tubular member 42A to the interior of the housing 14A causes the total volume of the compartment 46A to decrease and expels a small amount of indicator liquid towards the outside to displace the impurities, the two connecting members 12A and 12B having a liquid reserve to allow several linking operations.

The operator then continues the connection by pressing the plug element 12B in the direction of the arrow F. This further compression has the effect of carrying out an axial displacement of the element 42B in relation to the housing 14B, further than the first position the element occupies according to fig. 6, towards its second position indicated in fig. 7.

In the same way as during the previous coupling phase, the sliding movement of the element 42B has the effect of turning the second shutter 44B towards the inserted position shown in fig. 7.

During this movement, the two rooms 46B and 46A are in communication with each other via the openings 54A and 54B which at this point are released from the corresponding parts of the closing valve.

It appears from fig. 7 that the end surfaces 24B and 24A are completely free in relation to each other and not yet in mutual contact, thereby ensuring a good transmission quality of the optical

signals.

Fig. 7 further shows that the sliding inner sleeve 26B always has its axial position in relation to the housing 14B and whose front end surface 24B is in the interior of the housing 14B and behind in relation to the opening 54B.

To bring the two end surfaces 24A and 24B into contact with each other as shown in fig. 8, the operator presses further against the element 12B which is held in the hand by means of the closing jacket 98B.

All of this last compression force is transferred via the plug 102B and the radial projection 104B to the sliding inner sleeve 26B. The final force effort to bring the connecting elements together is somewhat greater than that needed to perform the previous phases of the compression and has the effect of releasing the locking mechanism with the balls 94B and thereby the sliding inner sleeve 26B which, after release, can be displaced axially in the direction of the plug element 12A.

During the movement leading to the final coupled position shown in fig. 8, the cylindrical surface of the mantle 98B slides in relation to the sleeve 92B and the tubular element 42B which is connected thereto and which cannot move axially to the right in the figure due to the common abutment between the outer surfaces 56A and 56B and the abutment between the element 42A and the radial opposite approach 50A, as this facility is the one that was established last.

The operator's last effort thus allows the sleeve 26B to slide until the surfaces 24A and 24B come into contact as shown in fig. 8.

It should be noted that the displacements carried out by the individual components, between the positions shown in fig. 7 and 8 are carried out within a clean liquid medium and so that no contamination or foreign particles can enter between the parallel surfaces 24A and 24B.

The connection of the two connection elements in the joint can optionally be terminated by locking in the connected position (using elements that are not shown here).

A disconnection of the elements will take place in the opposite order to what is described here, by starting by pulling in the opposite direction of the arrow F in the mantle 98B and whose withdrawal in relation to the sleeve 92B is facilitated by a compression spring 106B between the rear plug 102B and the flat facing sleeve 92B.

Claims (10)

1. Joint for connecting, in particular under water, two light conductors (20A, 20B) each of which has one or more optical fibers and such that the ends of the light conductors (22A, 22B) are guided towards each other, of the type comprising two complementary connecting elements ( 12A, 12B) which can be axially pushed together, one inside the other, where each connecting element has a housing (14A, 14B) which defines an internal space (46A, 46B) for receiving its respective light guide end (22A, 22B) and which before the joining of the connection elements and their housing is open in the direction towards each housing's front connection or coupling end, where each connection element (12A, 12B) further comprises a closing device (44A, 44B) for closing the space (46A, 46B) and the closure of which and opening can be controlled by the joining of the two connecting elements, where the closing devices (44A, 44B) comprise their respective dampers which can be moved between a first end position, spring-loaded against the spring action of a spring device (76A, 76B) to close the space (4 6A, 46B) when the two connecting elements are not joined, and a second end position where the damper is retracted when the two connecting elements are joined, where the two closing devices (44A, 44B) further comprise their respective movable mechanism (42A, 72A, 74A , 42B, 72B, 74B) to displace its respective closing damper between the end positions, and where each movable mechanism during the joining of the two connecting elements can be displaced by means of a control device which is moved on the second connecting element, CHARACTERIZED IN THAT each damper (44A, 44B ) is arranged rotatably about an axis normal to the connecting elements' (12A, 12B) central, longitudinal center axis (X-X), between a first angular end position for closing the space (46A, 46B) in a sealing manner, and a second retracted angular end position, that each movable mechanism for displacing its respective damper comprises a tubular member (42A, 42B) at the front end of which the damper is rotatably fixed, the tubular member being slidably movable in its respective housing (14A, 14B) between a first axially advanced position in relative to the housing and spring-loaded towards this position by its respective spring device (76A, 76B), and a second axially retracted end position relative to the housing, that each movable mechanism for displacing the rotatable damper includes means (72A, 74A, 72B, 74B) disposed between the damper and the housing for effecting rotation of the damper between its closed and retracted angular positions under the action of the corresponding axial displacement of the movable mechanism between his advanced and his retreated position, and that each of the control means for closing the second connecting member is formed by the front outer surface (56A, 56B) of the respective tubular member (42A, 42B), which front outer surfaces are arranged to cooperate with each other during the joining of the two connecting members to effect longitudinal displacement of each of the tubular elements (42A, 42B) towards its axially retracted position, for which position the associated damper is brought to its retracted angular position. 2. Joint according to claim 1, CHARACTERIZED IN THAT the mechanism comprises at least one control cam (72A, 72B) arranged on the shutter (44A, 44B) and which cooperates with at least one fixed cam (74A, 74B) which is connected to the housing (14A, 38A) , 14B, 38B) and which extends parallel to the axis of rotation of the damper. 3. Joint according to claim 2, CHARACTERIZED IN THAT the closing damper (44A, 44B) is designed as a spherical element with an internal recess (58A) which is bounded by two parallel side surfaces (60A) which stand normally on the turning axis of the closing damper and between which an extension ( 38A) in the housing extends, the extension comprising two lugs (74A) which face each other, align and are arranged to be received in two parallel and opposite grooves formed by the ridges (72A) in the side surfaces (60A). 4. Joint according to claim 3, CHARACTERIZED IN THAT the spherical outer surface of the shutter is arranged to abut against complementary inner surfaces (68A, 68B) of the tubular element (42A, 42B). 5. Joint according to one of the preceding claims 1-4, CHARACTERIZED IN THAT the front end (54A, 54B) of each of the tubular elements (42A, 42B) delimits an opening (54A, 54B) as the shutter (44a, 44B) cooperates with. 6. Joint according to claim 5 in combination with claim 4, CHARACTERIZED IN THAT the inner surfaces (68A, 68B) are formed on the inner surface of an internal radial shoulder (52A, 52B) in the front part of the tubular element (42A, 42B) which delimits the opening (54A, 54B), and that the outer spherical surface of the closing damper (44A, 44B) rests resiliently against the inner surfaces (68A, 68B) as a result of the spring action from a helical compression spring (76A, 76B) which is on one side abuts against the outer surface of the shutter and with its other end rests against a radially opposite and internal shoulder (50A, 50B) in the housing to guide the tubular element under spring force towards its first position. 7. Joint according to one of the preceding claims, CHARACTERIZED IN THAT the end (22A) of the light guide (20A) has a first connection element (12A) and is axially immobilized in relation to the housing (14A, 26A) for the first connection element (12A), and that the end (22B) of the light guide for the second connecting element (12B) is arranged to slide relative to the second element's housing (14B), between a retracted position behind the opening (54B) of the space (46B) and an advanced, connected position in contact with the end (22B) of the first light guide (20A). 8. Joint according to claim 7 in connection with one of claims 1-6, CHARACTERIZED IN THAT the light conductor (20B) connected to the second connecting element (12B) is fixed in a sleeve (26B) which can slide in relation to the housing (14B), and that a locking mechanism (94B, 96B) is arranged for locking the retracted position of the sleeve (26B) in relation to the housing (14B). 9. Joint according to one of the preceding claims, CHARACTERIZED IN THAT the space (46A, 46B) is sealed in the closed position by the shutter (44A, 44B), and that each connecting element (12A, 12B) comprises elements (86A, 86B) for maintaining the internal pressure in the room, at a pressure value that corresponds to the ambient pressure. 10. Joint according to one of the preceding claims, CHARACTERIZED IN THAT the end (22A, 22B) of each of the light guides (20A, 20B) has a device to enlarge the outgoing light bundle from the light guide, and that the light transmission is carried out between two parallel optical contact surfaces.