CA1239669A - Inductive electric connector - Google Patents

Abstract

ABSTRACT:

Inductive electric connector having a primary winding (12) and a secondary winding (13) as well as a magnetic circuit (11) for the windings. The magnetic circuit may be closed or opened so as to establish a connection, or to interrupt the connection, respectively.
The magnetic circuit (11) comprises at least two disk shaped elements (21a, 22a, 21b, 22b) having surfaces in engagement with each other and being mutually dis-placeable parallel to the engagement surfaces, in order to close or open the magnetic circuit . One of the windings may be removed from the magnetic circuit after the opening thereof, during a disconnecting operation.
The main field of use is in electric underwater instal-lations.

Description

i23~669 Inductive Electric Connector.
In offshore oil production a cooperation must often be established between structures installed on the sea bottom at different times and/or being located widely spaced. According-ly a need arises Eor power and signal transmission between the structures.
To make electric connections in the sea is a task invol-ving particular problems, and the need for better solutions is strongly felt. ~oth inductive and conductive connectors are used. Electrically conductive materials as used in conductive connectors corrode in sea-water and efforts have been made to displace the sea-water during the coupling operation and to take care that the water is kept out. For use under sea during several years all methods of keeping the water closed out have proved to be uncertain. Inductive connectors or couplers therefore have become popular for such uses, since they do not imply the exposition of electrically conductive material to sea-water any time.
An inductive connector in principle consists of two win-dings (electrically conductive) and a magnetic circuit, so arranged that these two windings as desired may be separated, or may be mutually coupled to form a transformer by means of the magnetic circuit. This of course is based upon the use of alternating current for the transmission of signals or power of greater magnitude. The transmission is operative when both windings together with the magnetic circuit form a transformer, but this transformer must be divided in some way or other in order that the connection may again be interrupted.
Such known arrangements have a number of drawbacks. Thus, there may be mentioned a number of drawbacks being related to the fact that the magnetic circuit is divided, so that the mag-netic field must cross a gap of non-magnetic material. Important properties such as impedance, coupling factor and load are critically dependent upon the magnitude of the gap and a pos-sible partition wall of metal. All desired properties are suffering with an increasing gap, and therefore this is made lZ3~6~

as small as possible. Therefore, there is often used a thin mem-brane of an alloy being resistant to sea-water, as a sealing along the separating surface, or the sealing is completely abandoned to let both transformer parts be exposed to the sea at the separating or dividing surEace. In the first case the transmission losses are increased and in the last case there will be problems with the protection of the windings against the sea-water. In all events the properties of the transmission will vary significantly from one connecting operation to the next, even when the separating surfaces are washed before connecting.
It is common to all the known arrangements that the magne-tic alternating field must pass to and from between both connector parts in order that transmission shall take place. Therefore, they are subject to the same objections as mentioned above. Besides, it applies to all known arrangements that each of the connector parts will have a strongly reduced inductance when they are separated, so that the transmission is to a high degree short-circuited. This may make it necessary to cut down the operation of a large plant only because a single connection shall be manipulated.
Thus, more closely the invention relates to an inductive or electric connector, in particular for underwater use, of the type comprising a primary winding and at least a secondary winding as well as a magnetic circuit adapted to interconnect the primary and the secondary windings magnetically, and to be opened so that the connection may be interrupted.
What is novel and specific to the arrangement according to ~239669 the invention is that the magnetic circuit comprises at least two disk-shaped elements having mutually displaceable engagement sur-faces which maintain a close contact between their major portions, every second element being displaceable in relation to the inter-mediate elements by sliding movement at the mutual engagement sur-faces.
As will appear from the following description a particu-larly preferred embodiment of the connector according to the inven-tion is based upon a number of the disk shaped elements which to-gether constitute a magnetic circuit ln the form of a package and which are adapted to be mutually displaced by a rotary movement.
The invention as well as additional novel and specific features thereof shall be explained more closely below with refe-rence to the drawings, in which:
Figure 1 simplified shows the principle of known arrange-ments of inductive connectors, Figure 2 shows the shape of one type of disk elements being incorporated in the preferred embodiment of the connector ac-cording to the invention, Figure 3 shows a second type of disk element incorporated in a preferred embodiment of the connector according to the inven-tion, Figure 4 shows an assembly of elements according to Figu-res 2 and 3 for forming a package which constitutes the magnetic circuit in the preferred connector, this package being shown in an open condition here, 3a Figure 5 shows the package of Figure 4 in a closed condi-tion, i.e. with the magnetic circuit closed, Figure 6, appearing on the same sheet as Figure 1, is a simplified perspective view of a winding in the form of a single turn adapted to cooperate with a magnetic circuit package having a fundamental structure like the packages in Figures 4 and 5, Figure 7, appearing on the same sheet as Figure 1, shows a simplified axial section through the winding of Figure 6, Figure 8 shows a separate winding adapted to be magneti-cally coupled to another winding (as for example shown in Figures 6 and 7), by means of a magnetic circuit as shown in Figures 4 and 5, Figure 9 shows a cross-section through the lower portion of the winding in Figure 3, Figure 10 shows a tubular sleeve or shell member intended for enclosing a magnetic circuit as shown in Figures 4 and 5, Figures lla and llb illustrate a complete arrangement com-1~23966~

ofposedycomponents as shown in Figures 6 to 10, in side elevation and end elevation, respectively, before being connected, Figures 12a and 12b show the arrangement in Figure 11, but in a connected condition, Figure 13 shows a modified embodiment of the connector according to the invention.
Figure 14 shows schematically and simplified another modi-fied form of the connector according to the invention, Figure 15 shows the same arrangement as Figure 14 from one end and partly in section, Figure 16 shows schematically and simplified still another modification of the invention, Figure 17 shows the arrangement of Figure 1~ from one end and partly in cross-section, and Figure 18 shows a cross-section along line X-X in Figure 17.
Figure 1 shows the known arrangement which is more or less dominating for inductive connection of underwater structures.
In Figure 1 there is shown a magnetic circuit 1 and windings 2 and 3, whereas reference numeral 4 depicts the separating sur-face which makes it possible to disassemble both windings.
Thus, in Figure 1 the transformer is divided into two similar parts which may be brought together or separated from each other.
If these two parts shall be sealed watertight from each other under all conditions, there must be provided a watertight wall at the separating surface therebetween. When they are connected to each other, the transmission is effected by the magnetic al-ternating field which passes to and from through the water-tight wall.
Figure 4 shows a magnetic circuit built up according to a preferred embodiment of this invention. The magnetic circuit, being here shown in its open condition, consists of a number of plane parallel elements in the form of disks 21a, 22a, 21b, 22b and so forth, made of a suitable magnetic material, pre-ferably of the ferritic type. The disks are essentially cir-cular and have a substantially circular hole in their central ~L239669 portion. This package 11 of disk e:Lements constituting the mag-netic circuit, comprises two sets of elements, whereby the disk elements in both sets have similar main shape, but ~eviate somewhat in certain details. This is apparent from Figures

2 and 3.
At this point reference is made again to Figure 4 in which there is also purely schematically indicated two windings 12 and 13, respectively. Through the magnetic circuit in the form of the above package 11, these may be magnetically connected so that electrical energy or electrical signals may be trans-ferred between both windings and thereby between equipment orcables, etc. to which these two windings are connected. Thus, in principle this is an inductive connector which may replace a common purely conductive connector, for example a plug and socket contact in certain fields of use. In Figure 4 the mag-netic circuit is shown in its open condition, but upon rotation of every second disk element in relation to the remaining ele-ments and through a sufficient angle, the magnetic circuit will be closed as shown in Figure 5. For this closing of the mag-netic circuit the elements 22a, 22b and so forth are rotated through an angle of 180, whereas the remaining elements, i.e.
the elements 21a, 21b and so forth, necessarily are kept stationary.-In the packages of Figures 4 and 5 the first disk element21a, the third disk element 21b and so forth, may be regarded as constituting a first set of elements. The intermediate ele-ments 22a, 22b and so forth, may be considered as constituting a second set of elements in the package. The shape of the ele-ments in the second set is shown in Figure 2, whereas the shape of the elements in the first set is shown more closely in Figure 3. Both types of elements have a sector shaped opening or recess 26 which leads to the central hole. The element in Figure 3 has a circular central hole 25, whereas the hole 27 in Figure 2 is somewhat modified or profiled in relation to a circular elementary shap~. The profiling is represented by two projections or driver notches 28a and 28b which constitute means for causing the relative rotary motion between the ele-ment sets. At its outside circumference the element of Figure

3 has three driver notches or projections 24a, 24b and 24c which also serve to obtain the rotary motion. When all disk elements are ordered as in Figure 4 having all openings 26 123~6~9 in alignment with each other, there will be formed an open channel along one side of the whole package so that access is possible -to the central passage formed by the holes 25 and 27 in the elements. In this open position of the magnetic circuit it is therefore possible to insert a winding for example as indicated at 12 and 13 in Figure 4, so that the current in the winding induces a magnetic field in the magne-tic circuit and vice versa. Thus, in principle there is established a transformer as discussed in the introduction to this description.
With windings inserted as indicated in Figure ~ the mag-netic circuit may then be closed by turning the two sets of disk elements in relation to each other as previously mentioned, and there is obtained a closed magnetic circuit as shown in Figure 5. Means for obtaining the necessary rotary motion and besides more practical embodiments of the windings shall be ex-plained in the following.
A specific example of a winding intended for cooperation with a magnetic circuit in the form of a package with disk elements as illustrated in Figures 2 to 5, is shown simplified in Figures 6 and 7. Here there is indicated a device 30 which may be an equipment of some kind to which electric current shall be supplied, possibly return electric signals by means of a cable or the like. The connection shall be established with an inductive electric connector according to this inven-tion. Accordingly, the device 30 is provided with a projecting winding having portions 31, 32 and 33 as shown in Figure 6, of which portion 31 is adapted to be enclosed by a magnetic cir-cuit as indicated in Figure 7, wherein 39 designates the mag-netic circuit or element package. In this example this package is much shorter in relation to the diameter than in the embodi-ment shown in Figures 4 and 5. As apparent from Figure 7 the winding is formed by a single turn in the form of a solid loop 35 of an electrically conductive material, preferably copper.
At its upper inner end the winding 35 is welded directly to chassis or earth in equipment 30, namely a plate member 30a.
As a protection and insulation around the winding 35 there is shown an insulating layer 36 which like the actual winding 35 is made of a material withstanding rough conditions, as for example may occur during underwater operations in connection with oil activity. The lower portion of the winding or turn lZ;~9~;69 35 is extended into the equipment 30 through a sleeve 37 so that the inner end 38 of the winding may be connected to electric circuits or the like in equipment 30. It is clear that this design with a single loop or turn makes it possible to obtain a very rugged and mechanically strong winding which is intended to be exposed to the ambient sea-water. Thus, the insulating layer 36 is a sea-water resistant, rugged and water-tight continuous coating. Possibly this may continue inte-grally with a corresponding coating covering the contiguous part of the equipment 30. Even though a design with a single loop is advantageous in many uses, there may of course be made windings having several turns and still maintaining a suffi-cient mechanical strength~ The employment of a single loop does not involve any substantial limitations with respect to the electrical relationships in the connection, since possibly there may be provided a transformer in equipment 30 which per-forms the necessary step-up transformation if this should be desired.
As further apparent from Figures 6 and 7 the upper portion 31 of winding 35 is adapted to cooperate with the magnetic circuit 39, which primarily is an advantage since the portion 31 will be thinner than the opposite portion 33. This is due to the simple design with a direct connection of the upper end of winding 35 to chassis or earth, whereby the insulation will be simplified, whereas portion 33 requires an additional sleeve 37 or the like, inter alia for leading through plate 30a. Secondly it is an advantage in practice that the magne-tic circuit 39 or the other part of the connector may be mounted on the winding 35 in a direction from above, as will be apparent from the following.
If the loop or winding 35 in Figures 6 and 7 is considered to constitute a secondary winding, a corresponding primary winding may for example be shaped as shown in Eigure 8. A
cross-section of the portion 41 in Figure 8 is shown at a larger scale in Figure 9. The cross-section shows a number of turns 48 arranged in three groups adapted according to the ~239669 cross-sectional shape and the material thickness. The turns 48 are potted in an electrically insulating and impermeable material the exterior surfaces 41a, 41b and 41c of which are approximate parts of a circumscribing circle which in turn has a diameter being somewhat smaller than the diameter of the hole 25 and 27, respectively, in the disk elements (see Figures 2 and 3). The portion 41 of the winding in Figure 8 is thus adapted to be accommodated in the passage through the element package, whereas portions 42, 43 and 44 of the winding will be outside the package. At 45 there is indicated an output cable from the winding in Figure 8. Finally, there is shown a handle 46 which constitutes an integral part of the winding and which serves the manipulation, i.e. opening and closing of the connector.
The cross-sectional contour of the winding portion 41 as shown in Figure 9, comprises two grooves 47a and 47b adapted to cooperate with notches 28a, 28b, respectively, in one of the element sets, the shape of which is shown in Figure 2. These elements are therefore rotationally keyed to the winding por tion 41. Moreover, the cross-section of Figure 9 has a central depression 49 which serves to accommodate the other winding, for example a winding portion as shown at 31 in Figure 6.
Thereby these two windings together will more or less fill up the passage through the element package formed by the holes 25 and 27 in the respective sets of elements. In this connec-tion it is an advantag~ that the cross-section of the winding portion 31 in Figure 6 is circular.
With an element shape as shown in Figures 2 and 3 it is required to make a particular design of the windinq in Fi~ure 8 in order to make possible the assembly of this winding and the element package. This is due to the fact that the recess or opening 26 leading to the holes 25 and 27 has a transverse dimension at its inner end which is smaller than the diameter of holes 25 and 27. This mounting problem is solved by giving one end portion, for example the portion 42 of the winding in ~23966~

Figure 8, a contracted cross~section as seen in relation to the width of the cross-section in Figure 9. Then the elements may be moved in between the winding portions while lying flat paral-lel to the portion 41 and moved in a direction parallel thereto with the opening 26 facing the portion 42 which is thereby surrounded, and after that the elements are swung down and moved onto portion 41 so that this is enclosed in holes 25 and 27.
Therefore, in -the resulting element package that set of elements which consists of elements of the type in Figure 2, may be xo-tated by rotating the winding in Figure 8 by means of the handle 46.
While the winding portion 41 as explained above with refe-rence to Figures 8 and 9, constitutes an internal core or guide for assembling and aligning the disk elements in the magnetic circuit package, there is shown in Figure 10 a device for en-closing the exterior of the element package. According to Figure 10 this comprises a shell consisting of a sleeve-like tube length 50 having a longitudinal wide split 51 the width of which corresponds approximately to the outer width of the openings 26 in the disk elements. With dotted lines there is indicated a disk element 20 within the shell 50, with the ope-ning of the element directed towards the split 51. At the in-terior the shell 50 is provided with means 52 in the form of holes or cut~away portions corresponding to the projections on the circumference of one of the disk element sets, namely projections 24a, 24b and 24c as shown on the element of Figure 3. Accordingly it is this type of elements which are rotationally held in the sleeve or shell 50.
In practice the shell 50 has end plates in the form of a bottom and a cover (not shown) at both ends, these end plates having cut-away portions corresponding to the openings and holes in the disk elements, more closely defined like the ele-ment in Figure 3. Moreover, within the sleeve 50 at one or both sides of the element package there may be provided a cup shaped spring so that the whole magnetic package will be under an axial bias within the sleeve 50, i.e. between its end plates not being shown. Also the shape of these cup springs ~Z3~6~9 must then be adapted to the shape of the element.
It is obvious that the various parts and elements incorpo-rated in the assembled connector are matched with respect to mutual dimensions so that the necessary freedom of movement for mounting and rotary motion is present. ~ere it is of sig-nificance that the disk elements in the magnet circuit package in the closed condition thereof lie so tightly packed that there is no risk of air gaps worth mentioning, which may re-duce the actual magnetic effect. The cup springs mentioned are also significant in this respect. For the purpose of making possible the assembly of the element package within the sleeve 50 this is suitably split at a plane of symmetry through the illustrated handle 56 at the dividing plane 57 which goes centrally with respect to the split 51.
Figures ~a and 11b show the connector assembled and ready for connection. ~n equipment part 30' similar to the equipment 30 in Figure 6 has a projecting winding with portions 31', 32' and 33' and, moreover, is provided with a guide 60 composed of longitudinal rod elements 61, 62 and 63 as well as two approximately U-shaped hoops 64 and 65. These hoops have inwardly curved upper portions 64a and 64b and 65b, respectively, which from above approach each other to a mutual spacing corresponding approximately to the outer diameter of sleeve 50. Thus, with this arrangement the sleeve 50 with magnet circuit and the associated winding may be moved down-wardly from above with the opening leading to the passage in the magnet circuit package facing down as apparent from Figure 11b. This figure shows the end plate 58 of sleeve 50 and the corresponding opening 59. The handle 46 on the winding and the handle 56 on the sleeve are adapted to be closely in engage-ment with each other in this open position of the magnetic circuit so that this may be moved fully onto the upper winding portion 31' of the other winding. When this position has been reached the handles 46 and 56 are rotated away from each other so that the previously described rotary movement of both disk element sets is caused and the magnetic circuit is closed.
Thereby the disk elements assume a position as shown in Figure 123~6~;9 5. Figures 12a and 12b show the complete connector and the arrangement of Figures 11a and 11b after rotation of the handles 46 and 56 so that the magnetic circuit is closed and the induc-tive electrical coupling is established. As appears from Figure 12b the total mutual angular movement between handles 46 and 56 is approximately 180. As seen in particular from Figure 12a a portion of the element package 11 is visible through the split 51 in sleeve 50 in this position.
During opening and disconnection it is obvious that the operations will be the opposite of what is described above.
As seen from the above it will also be common practice that one of the connector parts, i.e. a freely projecting winding portion, is attached to some structure or equipment member. In underwater operations a diver will bring with him and mount the other connector part comprising the magnetic circuit package and the other winding which is assembled-there-with, and thereby establish connection by coupling as described.
Even though in principle it is irrelevant which of the parts is mounted stationary and which is the movable part, i~ will usually be most suitable that the simpler part, i.e. the single winding as for example shown in Figure 6, is fixed to the structure or equipment. When a diver brings with him the other connector part, he grasps around both handles 46 and 56 and knows that the connector is then open and ready for mounting.
The mating movement is facilitated by the guide arrangement explained with reference to Figures 11a and 11b.
Figure 13 shows a modified embodiment based upon the same principles as those above, but having a double magnetic package placed in a sleeve 70 with a corresponding extension, including two parts 70a and 70b each enclosing either of the magnetic circuit packages. In the middle of sleeve 70 there is provided a deep incision 71 between both element packages. Moreover, there is shown a winding with a handle 86 and a core portion 81 as well as a supply cable 85. There is also shown an equipment part 90 with a winding 91 and a guide arrangement 92. As seen from Figure 13 only the left magnetic circuit, i.e. under sleeve part 70~ will come into engagement ~23~669 with winding 91 and serves the inductive coupling which is the object of the arrangement. The other magnectic circuit corresponding to sleeve part 70b on the contrary is only intended to surround that winding which is associated with the complete magnetic circuit and which is represented by the winding portion 81 and the handle 86. The mechanical arrange-ment is so made that one element package is open when the other is closed and vice versa. With this modiEication it is obtained that under all conditions there is maintained a suffi-cient inductance in the movable part of the connector as seen from the cable 85, so that unfavourable or undesired load conditions are avoided. This may be of much significance in many fields of use.
In the modified embodiment in Figure 13 as well as in the embodiment of Figures 11 and 12, the handles 46 and 5~ and 86, respectively, serves an additional function in cooperation with hoops 64b and 65b or 83 and 84, respectively, in Figure 13. As apparent from these figures the length of the handles is approximately equal to the longitudinal spacing between the hoops, whereby these hoops will serve to localize or deter-mine the position of the movable part of the magnetic circuit package in relation to the stationary winding. This guiding effect will be particularly promoted in view of the somewhat inclined profile at the ends of the handles. Another favour-able effect is that the disk elements in the magnetic circuit package will not be subjected to axial loads.
In the embodiment of Figure 13 there are two magnetic circuit packages in a mutually axial arrangement. Figures 14 and 15 show another modified form of the invention, also based upon two magnetic packages 101A, 101B, but here being arranged side by side so that both disk element packages 101A and 101B
may surround a portion 102A, 103A, respectivelyl of the pri-mary winding as well as the secondary winding when a connection is established. Figure 14 shows very schematically these two windings 102 and 103 with terminals and winding portions 102A
and 103A, respectively, extending through the element package 10lA. The same arrangement is shown in Figure 15 seen from one ~23~669 end. This figure only indicates in principle how windings 102 and 103 are closed outsi,de element packages 101A and 101B.
In package 101A there is indicated an opening 10~ similar to what has been described with reference to preceding figures of drawings. In the central hole or passage in -these element packages there is shown the cross-sectional shape of winding portion 102A which more or less encloses the other winding por-tion 1 03A, the latter being of a circular rod-like shape with a diameter making it possible to remove winding portion 1 03A
from element package 101A through the slot in winding portion 102A coinciding with opening 103.
The fact that both windings 102, 103 run side by side through both magnetic element packages 101A and 101B in the complete length thereof, contributes to the attainment of a low stray field and good frequency response properties for sig-nal transmission. When disconnected a reasonable impedance is maintained by first opening one magnetic package, for example package 101s, so that the innermost winding 103 may be swung out of package 101B with the axis of the other package 101A as a pivot axis. When this has been done, package 101B is closed and the other package 101A iS opened. Then one winding 103 may be separated from the other winding 102. Package 1 01A is closed whereby winding 102 which is stationary in element packages 101A and 101B, will have the same impedance as originally.
If desired, the windings 102 and 103 in ~igure 14 may be so arranged that the primary winding is the outermost winding portion and the secondary winding is the innermost winding por-tion through one of the element packages, whereas the primary winding is the innermost winding portion and the secondary winding is the outermost winding portion in the other element package. During disconnection these two windings will then be adapted to be accompanied each by a separate magnetic element package.
As seen in particular from Figure 15 the innermost winding 103A is almost completely surrounded by the outermost winding 102A. This additionally contributes to a low stray field and good signal frequency properties. In this connection it is to ~239669 be noted that the stationary magnetic disks or the element package may be anchored to the outermost winding 102, whereas the set of rotatable magnetic disks may have a notch adapted to be in engagement with grooves or recesses in an outer cylind-rical sleeve being common to the complete magnetic package or being subdivided into suitable sections. Such a sleeve must have a groove running the complete length thereof and corres-ponding to the openings in the magnetic disk elements. These parts of the structure may correspond more or less to what is shown in Figures 2 - 5 and Figure 10.
Figures 16, 17 and 18 show another and particularly pre-ferred embodiment according to the invention. Also here there are two element packages 111A, 111s being arranged side by side, and adapted to cooperate with a winding 112 which forms one connector part or unit together with the element packages, whereas another winding 113 may be separated from or coupled to the other part as desired. Thus, winding 113 may be a stationary part belonging to some piece of equipment to which an electrical connection is to be made.
In this embodiment both windings 112 and 113 are each formed of one turn or conductor loop. This is not necessarily so, but it leads to a particularly rough design adapted to handle large currents at relatively low voltages. This means that the connection is not destroyed even in the case of damage or deficiencies which involves significant leakage currents.
The relative movement of the connector parts is illustrated to some degree in Figure 16, in which winding 113 is shown in another position 113', i.e. being partly removed from the mating connector part consisting of element packages 111A, 111B and the other winding 112. Thus, it is seen that winding 113 is separated from the other part by an axial or longitudinal move-ment as indicated with dotted lines. A transverse portion 113B of winding 113 must then be able to pass through the ele-ment packages 111A and 111B, which is made possible by having openings therein aligned in a common plane as shown in Figure 17. Figure 16 shows this transverse winding portion 113B' in dotted lines, about half-way through the element packages.

~2396~;9 The windings may here consist of two straight rods 113A
of copper for example and with a cylindrical cross-sectional shape. At their upper ends (as shown in Figure 16) these rod shaped winding portions are connected to the above transverse portion 113s which may be in the form of a flat bar lying gene-rally in the central transverse plane coinciding with the slots and openings in the element packages as illustrated by Figure 17. Thus, -this form of winding may be considered to be similar to a conductor loop projecting from an associated piece of equipment, cf. the embodiment of Figure 6.
The mating winding 112 is designed so as to enter and en-close the loop shaped winding 11~ by axial movement as indicated in Figure 16. Referring to Figure 17 winding 112 may consist of two parallel slotted tubes 112A, in which the slots in each tube are facing each other. The upper end of these tubes are mutually connected through a common joke 112B having an inverted V-shaped cross-section. As seen from the cross-sectional illus-tration in Figure 18 the above transverse bar 113s of winding 113 is adapted to be received within the U-shape of joke 112B.
Of course there must be sufficient tolerances between the various mating winding portions of windings 112 and 113, in order that the coupling operation movement may take place without diffi-culty. Moreover, these windings may be provided with insu-lating coatings as known per se.
AS will be understood from the above, it is sufficient with a relatively narrow opening in each of the disk elements in packages 111A and 111B, to enable the flat transverse winding portion 113B to be moved out of the element packages, as indicated at 113' in Figure 16. Thus, there is obtained a very large surface of engagement between the respective magnetic disk elements, i.e. with correspondingly small air-gaps.
Notches on the disk elements for effecting relative rota-ry movement thereof may be located unsymmetrically with respect to the opening in the disk elements. Then the element packages may be composed of identical disk elements being ori-ented alternatively with the notches to the right and to the left, respectively, with all the openings directed the same way.

~239669 The relative rotary movement of disk elements as described before, may be effected by means of an enclosing sleeve or shell having internal grooves, similar to what is described in connec-tion with Figure 10 for example. There may also be arranged for an automatic rotation of disk elements gradually during the relative longitudinal movement when winding 113 and the other connector parts are mated. This may involve helical cams or the like for example cooperating with notches as described above. For manufacturing purposes it may be an advantage that all disk elements are identical. The design offers much free-dom with respect to making possible various remote control ope-ratlons by opening and closing the magnetic circuit package by package as well as disk by disk, as the mating conductor parts are pushed together. As to reliability,the arrangements of Figures 14-15 and Figures 16-17, when having one single loop or conductor turn possess the advantage that at no point there will be any potential difference between both windings. This of course applies when the windings have the same polarity, i.e.
with terminals in principle at the same end of the magnetic circuits, as apparent from Figures 14 and 16. These windings only need protection against corrosion, whereas electrical insu-lation therebetween is actually superfluous. In practice this means thatfa~lts~ or damage in the corrosion protective coating chosen, does not automatically disturb the function of the connector. Thus, in case of a deficient insulation, the ope-ration of the connector may continue in part with a conductive type of connection.
The illustrated embodiment of the disk element package has the advantage of a smallgap in the magnetic circuit and thereby a low reluctance. This makes it possible to implement a connection having a high coupling factor and a low impedance.
n practice this means small losses and a good immunity against leaks. The coupling is reproduceable between successive connec-ting operations and makes it possible to avoid uncertainty with respect to load conditions and reliability in the remaining parts of the electric system in which this inductive electric connector might be incorporated.

~Z39669 The effective gap in the magnetic circuit may be additional-ly reduced by employing comparatively thin and well plane machined disk elements. In order to make the disks stronger every two thin elements may be cemented together against a com-mon reinforcement. If this cementing is electrically insulating there will also be a contribution to lower eddy current losses.
It may be of significance to use materials in these elements to obtain a low mutual friction when surrounded by water, and a favourable effect of water lubrication may be an advantage in many cases.
The structure described involves good possibilities of sealing against penetration of water to sensitive or essential points and components in the connector. As mentioned it is, moreover, practical to work with good tolerances in various directions in view of the mating operation. This makes the work easier for divers and is also favourable for the purpose of a possibly remotely controlled operation.

Claims (17)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. An inductive electric connector, in particular for under-water use, comprising a primary winding and at least one secondary winding as well as a magnetic circuit adapted to couple the primary and the secondary windings mutually and to be opened so that the connection is interrupted, one of the windings being adapted to be removed from the magnetic circuit when this is opened under the disconnecting operation, and the magnetic circuit comprising at least two elements which have mutual engagement surfaces, characte-rized in that the elements of the magnetic circuit are disk shaped, that for opening and closing the magnetic circuit the elements are mutually displaceable at the engagement surfaces while maintaining a close contact between the major portion of the engagement surfa-ces, and that every second element is adapted to be displaced in relation to the intermediate elements by sliding movement at their mutual engagement surfaces.

2. Connector according to claim 1, characterized in that the disk shaped elements are arranged in the form of a package wherein the elements are arranged with their flat sides in engagement with each other, that each element has a recess from the pheriphery into the element, that the recesses in all elements together form a pas-sage through the package, and that the primary and secondary wind-ings are shaped so that a portion of both windings can extend through the passage, whereas the windings otherwise are closed outside the element package, whereby the through passage is main-tained when the magnetic circuit as a whole is closed or opened, respectively.

3. Connector according to claim 2, characterized in that the disk shaped elements are mutually displaceable by a rotary movement about a central axis of the element package, and that this central axis is located within the through passage.

4. Connector according to claim 3, characterized in that the recesses in the elements at their innermost end have an enlarged hole which together form the through passage.

5. Connector according to claim 4, characterized in that the periphery of the elements is substantially circular.

6. Connector according to claim 5, characterized in that every second (first set) element on their periphery are provided with devices for cooperation with a first displacement device for said rotary movement, and that the intermediate (second set) ele-ments on the circumference of the enlarged hole are provided with devices for cooperation with a second displacement device for said rotary movement.

7. Connector according to claim 6, characterized in that the devices on the pheriphery of the first set of elements have the form of projections on the circular periphery.

8. Connector according to claim 6, characterized in that the second displacement device is formed by a primary or secondary winding the portion of which being located in the through passage, is designed for cooperation with said devices in the enlarged holes, and the portion of which outside the element package is provided with an actuating handle.

9. Connector according to claim 6, 7 or 8, characterized in that the first displacement device consists of a substantially tu-bular split sleeve the inner diameter of which corresponds to the diameter of the elements, and which have interior actuating devices for cooperation with the devices on the pheriphery of the elements in the first set, and that the first displacement device is provi-ded with a handle for manipulation together with the handle on said winding, so that the connector may be opened and closed, respecti-vely.

10. Connector according to claim 8, characterized in that the devices in the enlarged holes are in the form of profilings of a substantially circular hole circumference, and that the cooperating portion on said winding or windings has a cross-sectional shape which is generally complementary to said profilings and the circu-lar hole circumference, except for a depression intended to accomo-date the other winding or windings to be placed in the passage du-ring a connecting operation.

11. Connector according to claim 2, characterized in that the one of the windings which is not associated with the element package in disconnected condition, consists of a single turn or loop.

12. Connector according to claim 11, characterized in that said turn has one of its ends connected to chassis ("earth") in the equipment part to which it belongs, and that the adjacent portion of the turn is adapted to enter the passage in the element package.

13. Connector according to claim 3, characterized in that it comprises guides for guiding the radial mating movement of the ele-ment package with windings with respect to the other winding so that a portion thereof enters the open magnetic circuit.

14. Connector according to claim 13, characterized in that the guides are adapted to cooperate with outer end portions of said handles so that there is obtained a well defined mutual position of the parts in the axial direction of the connector; whereby the ele-ments are not subjected to axial loads.

15. Connector according to claim 2, 3 or 4, characterized in that in addition to said element package which provides for magne-tic coupling of the primary and the secondary windings there is provided another element package which can only enclose the one of the windings being associated with the element package or packages, and that the other element package is influenced by the same displa-ement devices as said first element package, but in such a manner that the magnetic circuit in the other element package is open when the magnetic circuit in the first element package is closed and vice versa.

16. Connector according to claim 2, 3 or 4, characterized in that the magnetic circuit consists of two element packages and that portions of both windings are adapted to extend through both ele-ment packages, and that the element packages are adapted to be clo-sed and opened, respectively, independently of each other, so that one portion of a winding may first be removed from one element package, whereupon this element package is closed and the other package is opened, in order to remove the other portion of said winding.

17. Connector according to claim 2, 3 or 4, characterized in that the magnetic circuit consists of two element packages and that portions of both windings are adapted to extend through both ele-ment packages, that said winding portions are adapted to extend ge-nerally along a straight line and parallel through both element packages, that the relative movement between the removable winding and the element packages is adapted to be substantially in the same direction as the parallel winding portions, and that opening of the element packages enables a transverse portion interconnecting the parallel portions of the removable winding, to be moved through the element packages.