US 3786397 A
A cable termination is disclosed by which to connect and disconnect a suspension cable to and from a submersible electrical apparatus. The structure is arranged for high reliability in the mechanical and electrical phase of the connection and in the exclusion of water from the interior of the connectors.
Description (OCR text may contain errors)
[ Jan. 15, 1974 2/l963 l/l968 7/1968 2/1972 2/1972 Hamel 339/94 R X Karol 339/101 Koehler 339/101 X OBrien et a1 339/94 R Massa 339/102 R FOREIGN PATENTS OR APPLICATIONS France Primary Examiner-Alfred R. Guest At!0rney-R0bert C. Smith et a1.
ABSTRACT A cable termination is disclosed by which to connect and disconnect a suspension cable to and from a submersible electrical apparatus. The structure is arranged for high reliability in the mechanical and electrical phase of the connection and in the exclusion of water from the interior of the connectors.
21 Claims, 4 Drawing Figures CABLE TERMINATION This invention relates to improvements in apparatus for suspending, and for making electrical connections to, a submersible electrical apparatus. While the invention has general application to those situations in which it is necessary to lower a sonar unit or pump or other electrical or electronic apparatus into a body of water from an air or water-borne craft and to operate it while submerged, the invention is particularly useful in applications where the electrical apparatus and the suspension cable must be capable of withstanding rough handling and in which it is desirable to make the electrical apparatus easily detachable from the suspension cable.
An example of such a circumstance is found in portable submersible sonic systems. A sonic transmitter and hydrophone unit is suspended at the end of a cable whose other end is attached to a reel in an aircraft, most often a helicopter or on a ship. The cable interconnects the transmitter and the hydrophone with signal processing apparatus on board the craft. Such a system is used for a variety of purposes from detection of submarines to locating schools of fishes to locating and actuating valves and other apparatus associated with underwater pipelines and machinery. The submersible portion of the apparatus and its connecting cable are likely to receive rough treatment as a result of being lowered into and withdrawn from heavy seas or as a result of transverse movement of the aircraft while the unit is breaking the surface. In addition to the mechanical connection between the suspension cable and the submersible unit, there is a need to complete electrical circuits through the suspension cable into the submersible apparatus. That must be accomplished without any possibility that water can enter the apparatus.
Cables are especially subject to damage and must often be replaced. Prior apparatus for connecting the suspension cable to the electronic unit was constructed so that the apparatus was inseparable from the cable without being destroyed. Users of such apparatus have long sought a means by which the suspension cable could be removed from the terminal "-wet end connector to permit reuse of the connector. However, that requirement, important as it is, is less important than the requirement that such apparatus be dependable and operable when it has been taken in the field far out to sea where failure can have a far reaching and costly consequence. The result has been that prior apparatus has employed fixed and permanent wet end connectors. It is an object of the invention to provide an apparatus which makes it possible to reverse that situation. It is an object of the invention to provide apparatus whose form and reliability make it feasible to have a connector which is easily removable from the cable without suffering damage.
There are a number of difficulties that must be overcome in accomplishing that objective. A suitable apparatus includes a means for sealing against the entry of any sea water that could interrupt the proper electrical operation. Moreover, the completed terminal structure must cooperate with fittings on the submersible unit. Not only must the electrical and mechanical connection elements be aligned such that the electrical connection will be reliably completed as a result of mechanical interconnection, but the apparatus must be designed so that mechanical connection results in proper operation ofits seals. Further, some means must be provided by which to limit the degree in which the cable can bend at the point of connection to the submersible unit.
It is an objective of the invention to provide a means by which the electrical connection is made by a plug-in action which automatically places the mechanical connection elements, and the sealing elements, in position for completing a strong, waterproof connection. Other objectives are to provide a connector at reasonable cost, which is easily repaired, which is arranged to protect the cable at the connector against sharp bending, and which includes a means to protect against entry of water to the connector through breaks in the suspension cable sheath above the connector. Some of these objectives are realized and some of the advantages are obtained by arranging that element of the suspension cable that is to take the strain so that it is fixed to the detachable portion of the mechanical connector. The means by which cable bending is limited is also fixed to that detachable portion of the connector.
Other objects are to provide an improved anchoring means for securing the cable to a connector, to provide an improved sealing arrangement, to secure the advantage of a rigid stop for limiting cable bending without need to provide a full-sized stop.
These and other features of the invention will be more easily understood by examination of the preferred example of the invention selected for illustration in the accompanying drawings.
In those drawings:
FIG. 1 is a view of a submersible electronic apparatus shown partly in section and suspended on a cable which extends up through the recovery port, shown in section, of an aircraft which is not shown;
FIG. 2 is a view in vertical cross-section of connection apparatus taken on line 2-2 of FIG. 1;
FIG. 3 is a pictorial view ofa fragment of a spider employed in the apparatus of FIG. 2; and
FIG. 4 is a cross-sectional view taken on line 4-4 of FIG. 3.
In FIG. l the elctronic unit 10 that is suspended from suspension cable 12 is a typical submersible sonic unit with the exception that its upper end bell I4 is modified to accommodate the connection apparatus of the invention. The sonic unit includes a cylindrical housing 16 whose ends are closed by the end bell 14 at the top and an end bell 18 at the bottom. The housing 16 is surrounded by a baffle 20 which is generally cylindrical except that it is provided with thickned, bumper portions at its upper and lower rims. These heavier sections at the top and bottom of the baffle serve as a mounting base for a number of piezoelectric units 22. Because of their rectangular cross-sectional shape, the area of which is small compared to the electrode length, these elements are commonly called staves. Electrical connection from the staves to the interior of housing 116 is completed through the support tubes 24 by which the staves, and also the baffle, are fixed to the housing. The staves are spaced around the periphery of the baffle so that each stave lies in a plane containing the central axis of the electronic unit. This arrangement, coupled with selective connection of staves to the signal processing circuitry within the housing 16, permits electronic analysis to determine direction of sonic signal sources. The electronic unit within housing 16 is powered by and controlled by apparatus contained in the craft to which the suspension cable 12 connects. In this drawing only the fitting 26, at which the support cable enters the craft 28, is shown.
Rough handling and buffeting of the submersible unit places a strain on the terminal apparatus by which the submersible unit is attached to the suspension cable and on the cable itself. The connection is bent and twisted and jerked. However, the connection apparatus shown in FIG. 1 is capable of withstanding such forces without interruption of the electrical connection from unit 16 to the cable 12 and without danger that water will enter at the connection. That apparatus includes a detachable connector and a means to limit cable bending. They are fixed together at the end of support cable 12. Those elements are combined with a novel inlet connector and fastener arrangement which in the preferred embodiment forms part of the housing of the submersible unit. In addition, in the preferred form of the invention the cable is specially connected to the detachable connector in a way that makes the combination of those elements novel.
Those structures are shown in FIG. 2 where the detachable connector 30 is shown to be mated with an inlet fitting 32. The latter is fixed to the wall 34 of the housing 16. The connector and fitting are clamped together by a set of lug bolts or eye bolts 36. Lugs 38 carried on those bolts are clamped by lug nuts 40 against a flange 42 at the lower end of the detachable fitting 30. The lug nuts are pivoted on pins 44 carried by ears 46 formed integrally with the housing 16. In this embodiment the lower end of the eye bolt is provided with a special lug extension 50 which serves as a stop to limit the degree in which the bolt can rotate out of vertical position. This feature is incorporated to insure that the elements of the fasteners are readily accessible from above the unit. A snap ring near the upper end of the lug bolt thread serves to prevent complete removal of the lug nut thereby to avoid any possibilities that the nut can be removed inadvertently and lost when replacement is being made in the field. In this embodiment there are three lug bolts as best shown in FIG. 4.
The fitting 32 is generally cylindrical and symmetrical about a central axis which, in this case, is coincident with the central axis of the housing 16. Midway along its length the outer diameter is stopped so that the lower portion has smaller diameter. The downwardly facing shoulder formed by the step rests upon a fiber washer 52 which in turn rests in a shallow recess formed in the upper surface of wall 34. The lower end of the inlet fitting 32 extends down into an inlet opening formed through the wall 34 concentric with the shallow recess. The outer surface of the lower end of fitting 32 is spaced slightly from the inner surface of that wall 34 opening but the space is sealed by an annular sealing member 54 which is seated in a peripheral groove that extends around the exterior of the lower end of the inlet fitting.
The inner wall at the lower end of the inlet fitting 32 is threaded to accommodate the external thread of the sleeve end 56 of the mounting plate 58 of an electrical connector whose main body 60 extends below that mounting plate. The interior of the body 60 is not shown but at its upper end it terminates in a glass header 62 which is shown in section. The header is the member bonded in the center of the plate 58 through which electrical connector pins 64 extend. The ends of the pins are not visible because they have been inserted into the body ofa female connector 66 which has a sliding fit within the sleeve 56 and is carried by the detachable connector 30. The mounting plate 58 is bolted to the inner surface of wall 34 by bolts 70. Thus the mounting plate 58 is fixed to the wall 34. The inlet fitting 32 is screwed to the sleeve 56 of the mounting plate and a seal 54 is included in what would be the water flowpath. Thus the inlet fitting 32 is secured rigidly to the housing 16 in a watertight connection.
The electrical connection is completed through a conventional jack and plug arrangement. Both the male part 60 and the female part 66 of that connector are commercially available units. The female connector is formed with an upper flange 74 which is provided with a groove around its circumference to accommodate an O-ring 76. The ring serves to seal the interior ofdetachable connection 30 against the entry of water when the connector 30 is detached from inlet fitting 32. When these elements are in assembled condition it is another seal 78 that prevents the entry of water.
The detachable connector 30 is generally cylindrical and symmetrical about its central axis. Its interior wall is provided with conformations that serve as stops for elements that are inserted within it. In this embodiment those conformations are shoulders formed at planes where the interior diameter of the connector is stepped. The lowermost shoulder at 80 serves as a seat for the upper surface of flange 74 of electrical connector 66. The connector is forced against the shoulder by a sleeve nut 82 whose extenral threads are engaged in the internal threads at the lower end of detachable connector 30. Nut 82 is turned up tight against the lower surface of flange 74.
The detachable connector 30 and the inlet fitting 32 are arranged so that they mate with one another in that the cylindrical lower end of the connector has a sliding fit within the cylindrical upper end of the fitting 32. The degree in which the connector is inserted into the fitting and the actual alignment of the connector and fitting are controlled by providing each of these members with a peripheral surface such that the two surfaces are engaged when the connection is made. The surfaces have a shape to compliment one another. Various shapes can be employed but the preferred arrangement, and the one shown in the drawing, is one in which the cooperating surfaces of the two members lie in a plane perpendicular to the common axis of the members so that they engage face on. In this embodiment, the peripheral surface of the detachable connector is the lower face 84 of the flange 42. The cooperating surface 86 of the inlet fitting 32 is its upper end face.
The annular sealing element or sealing ring 78 is interposed between the detachable connector 30 and the fitting 32 in a way such that in assembled condition it bears against both of those members sufficiently to prevent the flow of water between them. However, it is positioned so that it does not prevent actual engagement of the surfaces 84 and 86. This is accomplished by placing the sealing member in a space which is wedgeshaped in cross-section and has the connector at one of its tapered walls and has the fitting at the other of its tapered walls. The sealing member has size so that it is forced down into that wedge when the unit is assembled. In this embodiment the sealing annulus 78 is placed in a recess 90 formed around the outer surface of the detachable connector 30 just below the flange 42. The inner upper corner of the fitting 32 is cut away to form a chamfer 92 so that a downwardly and inwardly sloping, conical surface is formed. When the connector 30 and fitting 32 are assembled and the bolts 36 are turned up with the clamp lug 38 in engagement with the upper suface of the flange 42 back of the outer peripheral lip 96, the lug bolts 40 may be turned down until surfaces 84 and 86 are engaged. In that condition the sealing annulus 78 will be pressed firmly against the sloping surface 92 of the fitting and against the bottom of the recess 90 of the connector and the unit will be sealed against the entry of water between those two elements.
The suspension cable 12 is formed with a central cable which has sufficient strength to support the submersible unit and the connector and the cable. It is metallic or is made of some other material, like fiberglass, that is equivalent in strength and flexibility to a metallic cable. In addition to that central metallic cable 100, the suspension cable includes electrical conductors 102 which, as shown in FIG. 2, may comprise a number of inner conductors. The metallic cable and the conductors 102 protrude from the lower end of the protective sheath 104 down into the interior of the detachable connector 30. The lower end of the cable is bonded to the interior of the sleeve 106 which has a flange 108 at its lower end. The flange extends outwardly and overlies an internal shoulder 110 toward the upper end of connector 30. The upper exterior portion of the sleeve 106 is threaded and those threads are engaged by a nut 112 which is turned down against the upper end of connector 30 so that the flange 108 is seated firmly against shoulder 110.
A means is provided for anchoring the cable to the connector 30 and more particularly to its interior. In this embodiment tha means comprises a spider 114 which is circular and whose upper outer surface is pressed upwardly against an internal shoulder 116 formed on the inner wall of connector 30. The spider is split; the halves defining a central opening which is expanded to spherical shape midway along its length at 120. The metallic cable 100 extends through a ball 122 which is swagged over the cable and which is seated within the spherical socket 120. Tension in the suspension cable 12 is taken almost entirely by the support cable 100.
The spider is shown in FIG. 3 to comprise two semicircular pieces. One of those pieces has a part broken away to show that its walls are generally rectangular in cross-section and that a spherical socket is formed by them. The spider must be strong and for that reason is made of metal. Nonetheless, it is desirable that the cable be electrically isolated from the metal connector parts for several reasons. Accordingly, the spider is made non-conductive. That is accomplished by providing it with a hard coating of non-conductive material such, for example, as aluminum oxide or chromic oxide applied in a plasma jet.
The electrical conductors 102 extend through the openings of the spider down to the region where individual conductors are connected to the electrical connector 66.
There is a need to preclude water from entering the interior of connector 30 by flow between the sheath 104 of cable 12 and the tube or sleeve 106. That task is accomplished simply by bonding the sheath 1041 to the interior wall of the sleeve 106 with an adhesive. There is also a need to prevent the flow of water between the outside surface of the sleeve 106 and the inner wall at the upper end of connector 30. That is ac complished by the inclusion of one or more seals in the flowpath. In this embodiment scaling is accomplished by two O-rings which are lodged in recesses which extend around the outside surfaces of the sleeve 106. In this embodiment the upper end of connector 30 has reduced outer diameter and is itself sleeve-like. It is provided with external threads. Those threads are engaged with the internal threads of a cylindrical member 132 which is cup-like and fits bottom up with its flanged rim 134 seated against an upper external shoulder 136 of the connector 30 where it is held in place by a set screw 138. The bottom of the cup is formed with an opening through which the cable 12 extends. The cup forms part of a means by which bending of the cable is limited so that it cannot bend too sharply and so that it cannot kink. In this embodiment a stop is fixed to the top of the cup and in fact is made integral with it. The stop is made relatively rigid, in this case very rigid, and it is formed so that it has a wall encompassing the suspension cable. The stop wall tapers out to larger diameter in the direction away from the connector. In preferred form, that wall is flared outwardly to a bell-mouthed shape. The stop 140 in this embodiment has such a bell-mouthed shape.
The degree in which cable bending must be limited depends in large measure upon the physical character of the cable. A cable of the size shown in the drawing should not be permitted to bend as sharply as it could if the illustrated bell-mouthed stop were the only means to prevent bending. In the absence of an additional structure to prevent bending, the bell-mouthed stop would need to be longer and extend outwardly to much larger diameter. However, to avoid the necessity of employing a larger diameter while retaining the limiting effect of a substantially rigid outwardly tapered stop, a supplemental structure has been provided in the form of a sleeve which surrounds the cable over a portion of its length beginning at the stop and which serves to bias the suspension cable so that its axis, at the point where it is embraced by the sleeve, tends toward a position in which its axis is coincident with the axis of the connector element. A coiled spring will provide that function and will serve as such a sleeve. The function can also be provided by a sleeve of elastomeric material which is slipped over the cable and has fixed connection at its lower end to the stop 140. Such an elastomeric sleeve may have a central opening smaller than the outside diameter of the cable so that it embraces the cable elastically but that is not essential. The elastomeric sleeve may be combined with a coiled spring but that complication is not essential. In the preferred embodiment of the invention, the sleeve is simply an elastomeric memher which is fixed at its lower end to the stop by being molded over the stop. In FIG. 2 the elastomeric sleeve 152 is molded directly on the stop 140. Its lower outer diameter is the same as the outer diameter of the flange 134,. Its inner diameter is approximately equal to the outer diameter of the suspension cable 12. The elastomeric sleeve in the preferred embodiment extends down into the bell-mouthed stop 1410 so that the stop operates on the material of the sleeve rather than working on the suspension cable directly. Above the stop the elastomeric sleeve performs substantially the same function that would be performed by a coiled spring except that its spring rate is altered by its construction so that the upper end of the sleeve opposes bending in lesser degree than the lower end. This is accomplished by tapering the outer wall of the sleeve in the region of its upper end to a smaller diameter in the direction away from the connector 30. The taper is visible in the drawing. In addition, the spring rate at the upper end of the sleeve is diminished by forming grooves in its outer periphery. The depth of the grooves differ and the spacing between successive grooves differs. Thus, the spacing between grooves 160 and 162 is less than the spacing between groove 162 and the groove 164 next above it. Groove 160 is cut more deeply than groove 166 below it. At its very upper end the sleeve is provided with an ungrooved, and therefore heavy, section 170 and an end grommet 172. The function of those elements is to absorb shock if the unit is drawn up toward the carrying craft sufficiently to hard impact against the fitting 26 through which the suspension cable extends.
To prevent entry of water through the interior of the cable if the cable integrity is violated and in the event of failure of the external cable seal, a means is provided for sealing the cable end. Packing material 170 is employed in the preferred embodiment. It is pre-molded and placed on the cable end and around the support cable 100 and conductors 102. A compacting piston or clamp 172 is placed over the packing material and is compressed against the packing by a resilient bias means. In this case, bolts 174 press stacked disc springs 176 against the piston. The force with which those springs press upon the piston is made at least equal to the maximum external hydrostatic pressure.
Although I have shown and described certain specific embodiments of my invention, I am fully aware that many modifications thereof are possible. My invention, therefore, is not to be restricted except insofar as is necessitated by the prior art.
1. Apparatus for suspending and making electrical connection to a submersible housing for electrical devices comprising, in combination:
a. a housing having an electrical inlet fitting extending therefrom, the fitting having an opening surrounded by a peripheral surface;
b. a detachable connector having a through opening encompassed by a peripheral surface of dimensions to complement said peripheral surface of the fitting;
c. clamping means for clamping said inlet fitting and said detachable connector together such that said peripheral surfaces are engaged;
d. a suspension cable comprising a central support cable and electrical conductors encased in a covering sheath extending into the opening of said detachable connector, the cable and electrical conductors having ends protruding from the end of said suspension cable;
e. cable anchoring means for fixing the protruding end of the support cable to the interior of said detachable connector;
f. sealing means for preventing entry of water into the detachable connector and the inlet fitting.
2. The invention defined in claim 1 which further comprises:
electrical connection means for completing an electrical circuit from the interior of said fitting to said electrical conductors comprising interfitting electrical connectors one carried by said fitting and the other carried by said detachable connector and having electrical connection one of said electrical conductors.
3. The invention defined in claim 2 in which said anchoring means is insulated electrically from at least one of said metallic cable and said detachable connector.
4. The invention defined in claim 3 in which said anchoring means comprises a spider fixed to the end of said metallic cable and disposed within said detachable connector, the detachable connector being formed with means in the form of conformations engaged by said spider to limit movement of the spider in the direction from which the cable extends, the outer surface of said spider having electrical insulating quality.
5. The invention defined in claim 4 in which the anchoring means further comprises a ball through which the metallic cable extends and to which it is fixed.
6. The invention defined in claim 1 in which said detachable connector comprises a support cable embracing portion into which said suspension cable is inserted and to which the sheath of the cable is bonded.
7. The invention defined in claim 6 in which the embracing portion of said detachable connector comprises an outer sleeve and an inner sleeve fixed in the outer sleeve; said sealing means comprising a seal between the inner and outer sleeve and encompassing the inner sleeve, the sheath of the suspension cable being bonded by an adhesive to the inner wall of the inner sleeve.
8. The invention defined in claim 6 in which said sealing means further comprises packing means in the form of packing material and a clamp to force the packing material against the end of the suspension cable and said inner sleeve and around the protruding metallic cable and electrical conductors for sealing the end of the cable against the entry of water.
9. The invention defined in claim 8 in which said clamp is resiliently mounted and biased into engagement with said packing material.
10. The invention defined in claim 6 in which said sealing means further comprises a sealing annulus encompassing one of said detachable connector and said inlet fitting in position to be compressed against both of said detachable connector and said inlet fitting when said peripheral surfaces are pressed into engagement.
11. The invention defined in claim 10 in which said detachable connector and inlet fitting are generally cylindrical about a central axis and in which said peripheral surfaces are annular and are more nearly perpendicular than parallel to the central axis, at least one of said detachable connector and inlet fitting having an annular portion cut away at the inner margin of its peripheral surface to form, with the other, a sealing annulus retaining groove which is wedge-shaped in section tapering to smaller width in the direction parallel to said central axis, said sealing annulus being disposed in said retaining groove.
12. The invention defined in claim 11 in which said clamping means comprises a series of pivotable eye bolts having pivotal connection to said housing, nuts on said bolts and means on said detachable connector for cooperating with said bolts and nuts, when the bolts are pivoted to a given position, to clamp the detachable connector to said inlet fitting.
13. The invention defined in claim 12 in which said clamping ring further comprises locking means for preventing removal of said nuts from said eye bolts.
14. The invention defined in claim 6 which further comprises bend limiting means for limiting the degree in which the support cable can bend in the region above said detachable connector whereby sharp bends and kinks are prevented.
15. The invention defined in claim 14 in which said bend limiting means comprises a substantially rigid tapered mouthed stop through which said support cable is passed and which is fixed to said detachable connector with the mouth opening away from said detachable connector.
16. The invention defined in claim 15 in which said bend limiting means further comprises means in the form of a sleeve of elastic material encompassing a length of said suspension cable from a point within said tapered mouth stop, for biasing said suspension cable against bending.
17. The invention defined in claim 16 in which said sleeve is formed of elastomeric material and is shaped such that the degree of bias it imposes diminishes as a function of distance from the tapered mouth stop.
18. The invention defined in claim 17 in which the sleeve encompasses the cable, diminishes in diameter toward its end away from the tapered mouth stop, and is formed with circumferential grooves along its length.
19. The invention defined in claim 14 in which said bend limiting means comprises an elastomeric sleeve surrounding said cable and fixed at one end to said detachable connector, the sleeve diminishing in diameter in the direction away from that end and being formed with circumferential grooves whose spacing diminishes and whose dimensions increase at greater distance from said one end.
20. For attachment to an input connector which extends from an electrical housing, the combination of:
a. a detachable connector having a central longitudinal axis about which the connector is substantially symmetrical and having an attachment end for attachment to said fitting and having a cable end for receiving a suspension cable, the connector including an external flange nearer its attachment end than to its cable end, the connector further including a cable embracing portion at its cable end in the form of a sleeve through which a cable can extend;
b. a cable anchor in the form ofa spider of dimension to fit within said detachable connector, the interior of the detachable connector being formed with conformations to limit the degree in which the anchor is inserted toward its cable end;
0. bend limiting means for limiting the degree of bending permitted in a suspension cable after attachment of said connector to the cable said bend limiting means comprising a stop fixed to said detachable connector and having a central axis in alignment with that of the detachable connector and an opening communicating with that of the connector, the opening of the stop being tapered to greater inside diameter in the direction away from the connector, said bend limiting means further comprising an elastomeric sleeve having a central opening aligned with that of the stop and of size to encompass a support cable, said sleeve being formed to offer less opposition to bending in portions removed from said stop.
21. The invention defined in claim 20 which further comprises a length of suspension cable assembled with said detachable connector, stop, and elastomeric sleeve;
the suspension cable containing a central support cable, electrical conductors and a covering sheath, the covering sheath extending only to a point spaced from said cable anchor, the electrical conductors extending past the cable anchor, and the support cable being fixed to said cable anchor; and
sealing means for preventing entry of water into the interior of said detachable connector comprising packing disposed at the end of said covering sheath of the cable and surrounding the metallic cable and the electrical conductors.