IL34456A - Rigid electrical connector - Google Patents

Description

Rigid electrical connector THE BUHKER-RAKG CORPORATION This invention relates to electrical connectors and more particularly to an electrical connector which is adapted to maintain a substantially airtight seal between mating faces of the connector plug and receptacle by substantially preventing any relative movement between these elements under conditions of stress, shock or vibration.

One type of connector presently employed to interconnect two wires or two cables utilizes a bayonet pin on the receptacle shell which mates with a single-stage cam on the plug. This type of connector may be coupled quickly and easily, requiring only about a 120° rotation of a coupling ring with a minimum of torque, and also provides reasonable protection against the connection being opened as a result of stress, shock or vibration.

However, since the bayonet pin and cam cause a relatively large movement of the plug into the receptacle for each degree of rotation of the coupling ring, this type of coupling is capable of generating little power. As a result, the operator muet supply substantial torque in situations where compression of an insulator is desired in order to achieve an interfacial seal.

Also, since pressure is applied over a small pin and track area, attempts to form a pressure seal with this type of coupling results in excessive wear and possible shearing of the pin and in mushrooming of the cam track.

However, if a high-pressure interfacial seal is not achieved between the insulators of the plug and receptacle, moisture may get into the contacts causing shorting and other problems. An airtight seal between the plug and receptacle is even more essential when the connector is used in airborne equipment or other equipment which is called upon to operate at varying altitudes. Corona starting and extinguishing voltages are known to vary with the ambient air pressure and to decrease with moisture. Since a corona discharge can cause signal-destroying noise on the line '"■< that the corona starting voltage in the connector he maintained well above the voltage on the lines feeding the connector. A good interfacial seal in the connector prevents the pressure of the air trapped in the connector from varying regardless of the external pressure, and keeps moisture out of the connector. This assures that, so long as voltage levels in the connector do not exceed ground level ratings, a corona voltage will not develop in the connector.

With a bayonet coupling alone, it is difficult to achieve an 10 effective interfacial seal and the seal may be lost when the wires or cables are abruptly subjected to axial or rotational stress. Movement between the plug and receptacle shell, and thus loss of interfacial seal, may also occur during shock or vibration. In addition to the loss of interfacial seal, such movement could cause undesirable contact noise on the lines and could also cause excessive contact wear and erosion. Excessive wear reduces the life of the connector. This, in addition to the variations in the corona starting and extinguishing voltages, could lead to erroneous operation, or even loss of operation, in the equipment 20 serviced by the wires.

Prom the above it is apparent that, particularly in such applications as in airborne and other mobile equipment, where connectors are subjected to variations in ambient pressure, and where connectors are subjected to stress, shock and vibration, an improved electrical connector is required. This connector should be capable of providing an airtight interfacial seal between the plug and receptacle and should be rigid so as to prevent any relative movement between these two elements. However, it should still be possible to couple the plug and receptacle both quickly 30 and easily. Another desirable, but not absolutely necessary, feature is that the modifications to the connector be restricted to, for exam le the lu and that the modified lu be ca able would minimize manufacturing and design costs as well as reducing the cost of any required field changes.

It is therefore a primary object of this invention to provide an improved electrical connector.

A more specific object of this invention is to provide a connector with an airtight interfacial seal between the plug and receptacle so as to prevent changes in the corona starting an extinguishing potential from occuring in the connector when the connector is subjected to variations in ambient pressure such as are caused by changes in altitude.

Another more specific object of this invention is to provide a rigid electrical connector which minimizes relative movement, and thus prevents loss of interfacial seal, between the plug and receptacle under conditions of stress, shock and vibration.

Another object of this Invention is to provide a rigid electrical connector of the type described above, the plug and receptacle of which may be coupled both quickly and easily.

Still another object of this invention is to provide a rigid, airtight connector of the type described above, where all modifications are made only in the plug so that existing receptacles may still be utilized.

In accordance with the above objects this invention provides a connector formed of a plug having a shell and a receptacle having a shell. The plug has a coupling ring which is mounted for rotation on the plug shell. A first coupling means is provided which is adapted, when the ring is rotated, to loosely couple the plug and receptacle. This first means may, for example, be the usual bayonet pin and cam, described above. Each shell has a block of contact-supporting insulating material rigidly supported in it with each of the blocks having a forward face. The two forward faces are positioned parallel to each other when the plug and receptacle are loosely coupled. At least one of the blocks provided which is adapted to complete the coupling of the P11*^ and receptacle, The second coupling means is effective to force the forward faces of the insulating material blocks against ea£h other under pressure, causing a compression of the block which is formed of a compressible material. This results in the forming of a rigid and substantially airtight interfacial seal. The second coupling means may, for example, be a conventional screw thread which causes the plug shell to be advanced relative to the coupling ring. In a preferred embodiment of the invention means are provided for inhibiting the action of the second coupling means until the action of the first coupling means has been completed. The combination described above has the advantage of the bayonet coupling in that most of the coupling may be accompl shed quickly and easily while the screw thread provides the pressure required for achieving an effective interfacial seal with a relatively small amount of torque applied to the coupling ring. Further rigidity may be obtained by terminating the second coupling action with a metal to metal bottoming of the shell forward faces.

The foregoing and other objects, features and advantages of the invention will be apparent from the ollowing more particular description of preferred embodiments of the invention as illustrated in the accompanying drawings.

In the drawingsΪ Fig, 1 is a cutaway diagram of a portion of the connector of a preferred embodimen of the inventio showing the plug and receptacle in an uncoupled condition.

Fig. 2 is a cutaway diagram showing the plug and receptacle of Fig. 1 in a partially coupled condition.

Fig. 3 is a cutaway diagram showing the plug and receptacle of Fig. 1 in a fully coupled condition.

Fig, is a section view of the receptacle of the embodiment of the invention. rS^ Fig. 6 is a cutaway diagram of a portion of the connector of an alternative embodiment of the invention showing the plug and receptacle in a Coupled condition.

Referring now to Fig. 1, it is seen that the connector is formed of a receptacle 10 and a plug 12. Receptacle 10 includes a sheH 14 having a bayonet pin 16. e receptacle also includes a block 18 of insulating material having forward face 19 one or more female terminals 20 positioned therein. In the embodiment of the invention shown, block 18 is of an ^incompressible material. An opening 21 is provided between shell 14 and insulator block 18 in which, as will be seen shortly, the plug shell is adapted to fit. The shell has a key slot 22 formed in it at a point adjacent to opening 21 and a sealing gaske 24 of the 0-ring type is also provided. Referring to Fig. 4 i is seen tha insulator block 18 can in fact house a plurality of female terminals 20 which lead to an output cable (not shown)* While there is only a single key slo 22, there are three bayonet pins 16 uniformly positioned arouM the periphery of the shell.

Referring now to plug 12, it is seen that it includes a plurality of terminal pins 26 (only one of which is shown in the figure) embedded in and projecting from the front face 27 of a block of insulating material 28;, There is a terminal pin 26 corresponding to each female terminal 20* Block 28 will, for the embodiment of the invention shown, be assumed to be of a compressible (elastic) material.- It should be understood, however, that block 18 could be o a compressible material and block 28 of an incompressible material,: or both blocks could be formed of a compressible material, A plug shell 30 surrounds block 28, A coupling ring 3 is secured against longitudinal motio on shell by track-ring 34 whic rides in channels 36 and 38* Ring 32 is helical cam tracks 46 (only one of which is shown in FIG. 1), one for each of the pins 16 shown in PIG. 4.

Referring now to PIG. 53 it is seen that each of the tracks 46 provides a path which angles at 15° - 30 ' for a distance equal to 60° around the internal circumference of the bayonet sleeve. At 60°, a seat 48 is provided with the cam track having a 30° angle beyond the seat. The function of this last design feature will be described shortly.

Bayonet sleeve 44 has a groove 50 which is adapted to re-ceive a stud 52 of a coupling sleeve 4. The other end of stud 52 fits into a groove 5 in coupling ring 32. Coupling sleeve 4 is thus effective to lock the coupling ring and the bayonet sleeve together so that they rotate as a unit. Stud 54 is biased into groove 50 by return spring 58. As may be seen from the exploded portion 60 of PIG. 2, the left surface of stud 52 and the right surface (outside groove 50 ) of bayonet sleeve 44 are knurled surfaces. The function of these knurled surfaces will be described shortly.

In operation, receptacle 10 and plug 12 are initially posi-tioned as shown in PIG. 1 with key 31 in keyslot 22 and each of the bayonet pins l6 in a corresponding cam groove 46. Coupling ring 32 is then rotated (counterclockwise when looking in the direction of PIG. 4). Since bayonet sleeve 44 is fixed to coupling ring 32 by stud 52 of coupling sieeve 4* bayonet sleeve 44 also rotates relative to pin l6 causing each pin 16 to move along a respective cam groove 46. This results in plug 12 being drawn into receptacle 10. Part way through this operation the leading edge of receptacle shell 14 contacts the leading edge of coupling sleeve 54. Prom this point on, further advance of the plug into the receptacle causes coupling sleeve 54 to be moved backward relative to bayonet sleeve 44 against the action of return pieted, bayonet pins 1 are seated in seats 48 o cam tracks 4 (see Fig, 5) and the elements are positioned as shown in Pig. 2^ From this figure it can be seen that stud §2 of coupling sleeve 54 is now removed from groove 50· This permits the coupling ring and coupling sleeve to rotate relative to the bayonet sleeve.

During the remaining rotation of coupling ring 32, which may, for example9 be another 60°» threads 40 and 42 coact to drive plug shell 30 further into receptacle 10, As may be seen from figs. 2 and 3» most of this movement results in a compression in length of insulator block 2Θ by an amount (L). If bot blocks 18 and 28 are formed of a compressible material, then both blocks will be deformed, while if one of these blocks is formed of an incompressible material, then only the other will be compressed. The compression of the insulator block results in a high-pressure interfacial seal which is airtight and watertight and is highly resistant to any motion between the plug and receptacle due to stress, shock or vibration* Further sealing, particularly against moisture, is achieved through the deforming Of 0-ring gasket 24* As may be seen in Fig, 3, the coupling action terminates in a metal to metal butt joint between the leading edge; of plug shell 30 and receptacle shell 14. 33iis metal to metal butt enhances the rigidity of the connector.

The knurled surfaces between bayonet sleeve 44 and coupling sleeve 54 (see insert 60 of Fig. 2) are held together unde pressure by means of return spring 58. The mating of these surfaces serves to lock the coupled elements in place. This lock is designed to be resistant to vibration and shock.

Since the three bayonet pins 16 are seated for the final 60° of rotation, the lead edge of the cam track, and the bayonet pin, are not subjected to the high forces required to compress the insulating material blocks, fhus, mushroom effect on the cam tracks is minimized. If a proper seating is designed, seizing as The 30 elix angle is the cam track beyon the seat position 48 insures that the bayonet pins 16 will fall into ae seat and, at the same time, allows larger production tolerances for the coupling sleeve release mechanism.

When it is desired to uncouple receptacle 10 and plug 12, coupling ring 32 is rotated in the opposite direction. Since coupling sleeve 54 is keyed to coupling ring 32, this causes th© coupling sleeve to also rotate with the knurled surfaces shown in insert 60 riding over each other? When stud 52 reaches a position adjacent to groove 50, a stop is provided to prevent the stud from moving any further. Setura spring 58 forces stud 52 into groove 50. Continued rotation of coupling ring 32 causes bayonet sleeve 44 to also be rotated. Shis results in pins 16 moving through grooves 46 to cam the plug and receptacles out of contact with each other, A connector has thus been provided which permits a rigid, airtight and watertight connection with insulator compression and metal-to-metal bottoming of the shells, T is is accomplished with onlya 120° rotation of a coupling ring, Since a low-angle screw tread is utilized to perform the compression operation, the torque required for this operation is not excessive. fig. 6 shows an alternative embodiment of the invention which is substantially simpler, and therefore cheaper and less bulky, than that shown in Figs. 1-3· $ e primary difference in this embodiment of th© Invention is that the coupling action as a result of the bayonet pin and cam, and the coupling action resulting from the screw thread are performed concurrently rather than sequentially, this increases the torque required to effeot the connection, but permits the use of a plug having only two rather than four parts.

Referring to Fig. 6, it Is seen that like numbers have been used for like elements in Figs. 1-3 and Fig, 6, Receptacle 10 is 14 having a bayonet pin 1 and a key slot 22 formed in it, and a block of insulating material 18 which is adapted to ave a pluralit of female terminals 20.

Plug 12 still has shell 30 having a key 31 formed on it and a block of insulating material 28, having terminal pins 26 mounted therein Shell 30 has an external screw thread 70 formed On it which thread mates with an internal thread 72 of a bayonet coupling ring 74. Bayonet coupling ring 74 has a plurality of earn tracks 46 formed in it (only one of which is shown in Fig. 6) which tracks correspond in number to the number of pins 16 (three for the Illustrated embodiments of the invention), h© cam tracks may be of the type shown in Fig, 5. the torque required to effect coupling with a connector of the type shown in Fig, 6 may be reduced by extending cam track 46 for 120° rather than or 60° thus permitting the cam angle to be reduced. Bayonet coupling ring 74 is captivated on shell 30 b retainer ring 76, Ring 74 is rotated on shell 30 against the action of torsion spring 78.

In operation, receptacle 10 and plut 12 of Fig, β are fitted together much as is shown in fig. 1 with key 31 in key slot 22 and bayonet pins 16 in corresponding cam tracks 46, At this time ring 74 is held against retainer ring 76 by the action of spring 78.

Ring 74 is then rotated causing the plug and receptacle to be coupled due to the joint action of the bayonet pins and screw thread 70 * 72. $he coupling is completed as show in i . 6 when the pins 16 reach the end of cam tracks 46 and screw thread 72 reaches the end of screw thread 70, The pressure of the inter-facial seal results in a metal-to-metal butt joint on the threads 70 and 72 providing additional rigidity and locking the elements against becoming uncoupled, When it is desired to uncouple the elements, ring 7 is rotated in the opposite direction from that in which it was rotated for coupling. with reference to preferred embodiments thereof3 it will be tanderstood by those skilled in the art that the foregoing and other changes may be made in the nature and relationship of the parts without departing from the spirit and scope of the invention.

Claims (12)

34456/2 . ? 11 - C1AIMS

1. A connection means comprising a connector plug which is adapted to be coupled to a mating receptacle said connector plug comprising: a plug shell; a coupling ring mounted to rotate relative to said shell; a first coupling means adapted to coact with said receptacle, when said coupling ring is rotated, to substantially effect the coupling of said plug and receptacle; and a second coupling means operative in response to the rotation of said coupling ring to complete the coupling of said plug and receptacle.

2# The connection means as claimed in Claim 1, including a ma* ing receptacle, a receptacle shell* and a block of contact-supporting insulating material rigidly supported in each of said shells, each of said blocks having a forward face, said forward faces being positioned parallel to each other during the coupling of said plug and receptacle, at least one of said blocks being of compressible material, said second coupling means being effective to force said forward faces against each other under pressure, causing a compression of the blocks of compressible material to form a rigid, substantially airtight interracial seal.

3* The connection means as claimed in Claim 1, wherein said second coupling means is operative when said coupling ring is rotates past the point where the substantial coupling by said first coupling means has been effected.

4. The connection means as claimed in Claim 1, including means for inhibiting the operation of said second coupling means until the substantial coupling by said first coupling means has been completed.

5· The connection means as claimed in Claim 2, wherein said second coupling means terminates in the bottoming of said plug and - 12 - 3 56/2

6. The connection means as claimed in Claim 2, wherein sa ■i4d second coupling means ie adapted to advance said plug into said receptacle a relatively short distance for each degree of rotation of said coupling ring, whereby the compression of said block is achieved without requiring the application of substantial torque to said coupling ring.

7. The connection means as claimed in Claim 1, wherein said second coupling means is a screw thread.

8. The connection means as claimed in Claim 1, wherein said first coupling means is adapted to advance said plug into said receptacle a relatively large distance for each degree of rotation of said coupling ring.

9. The connection means as claimed in Claim 4, wherein said first coupling means includes a bayonet pin on said receptacle and a cam track formed in said plug, said cam track being adapted to coact with said pin, when said coupling ring is rotated, to substantially couple said plug and receptacle.

10. The connection means as claimed in Claim 1, wherein said firs and second coupling means are concurrently operable.

11. The connection means as claimed in Claim 2, wherein said first coupling means includes a bayonet pin on said receptacle shell end a cam track formed in said coupling ring, said cam track being adapted to coact with said pin, when said couplin ring is rotated, to couple said plug and receptacle.

12. The connection means as claimed in Claim 7» wherein said screw thread connects said coupling ring to said plug shell. 13· The connection means as claimed in Claim 9# wherein said cam track is formed in a bayonet sleeve of said plug which surrounds said plug shell; and wherein said means for inhibiting the operation of said second coupling means Includes a coupling sleeve whioh is nor 1 34456/2 • 13 - coupling sleeve being adapted to disengage said coupling ring and said bayonet sleeve when said substantial coupling of said plug and receptacle resulting from the coaction of said pin and said cam track has been completed. For the Applicants DR. REINHOLD COOT AND PARTNERS