US 3750087 A
Helical ramp grooves formed in the interior of a coupling ring act against bayonets or pins mounted on one half of the electrical connector to effect coupling with the other half. A specially tapered spring washer becomes effective during the coupling procedure to maintain a no-motion condition of the two components after the contacts thereof have been fully mated. Additionally, a plurality of detent balls are automatically shifted into a holding position at the completion of the coupling action, thereby further contributing to the maintenance of the mated or coupled condition of the connector parts.
Claims available in
Description (OCR text may contain errors)
nited States atent [1 1 Vetter July 31, 1973 PRELOADED ELECTRICAL CONNECTOR 3,552,777 1/1971 Heinrich et a1. 339/89 R Primary Exgn irre r. loseph H. McGlynn Attorney-Ralph L. Dugger, Stuart R. Peterson et al.
[5 7 ABSTRACT Helical ramp grooves formed in the interior of a coupling ring act against bayonets or pins mounted on one half of the electrical connector to effect coupling with the other half. A specially tapered spring washer be comes effective during the coupling procedure to maintain a no-motion condition of the two components after the contacts thereof have been fully mated. Additionally, a plurality of detent balls are automatically shifted into a holding position at the completion of the coupling action, thereby further contributing to the maintenance of the mated or coupled condition of the connector parts.
16 Claims, 6 Drawing Figures PATENTEUJUI. 3 1 mm 3 750087 sum 1 [IF 2 INVENTOR. OTTOMAR H. VETTER ATTORNEYS PATENTEBJULSI ma 3.750.087
SHEET 2 BF 2 POINT WHERE SPRING WASHER 68 IS POINT WHERE COUPLING INITIALLY DEFLECTED IS COMPLETED FIE-f BAYONET ADVANCE APPLIES WORKING RANGE PRELOAD START OF TO WASHER 68 BAYONET ADVANCE GROOVE IN COUPLING RING PERCENTAGE ROTATION OF COUPLING RING 58 |oo */o PERCENT 75 FORCE REQUIREDSO/ T0 5/ DEFLECT 2 WASHER 0% 68 0 5 o 50 o 75/ I00 @souo INVENTOR PERCENT DEFLECTION OTTOMAR H. VETTER OF WASHER ea BY ATTO RNEYS PRELOADED ELECTRICAL CONNECTOR BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to a preloaded elec trical connector, and pertains more particularly to a connector utilizing a specially configured spring washer to maintain the connector halves in their coupled condition.
2. Description of the Prior Art Bayonets or pins and associated helical ramp grooves have long been used for coupling together the two halves or components of an electrical connector. In an effort to assure that the two components remain coupled, the inner or closed ends of the grooves have been provided in the past with offset notches or pockets into which the bayonets move. While the retention goal has been achieved with such prior art arrangements, this has been at the sacrifice of other needed criteria. More specifically, there cannot be a so-called bottoming of one connector component with respect to the other. Also, the connector is vulnerable to vibration, wear and also other factors resulting in partial or complete electrical discontinuities. An example of a patent utilizing the notch or pocket detent arrangement at the closed end of the helical ramp grooves is US. Pat. No. 2,984,811 issued on May 16, 1961 to Hennessey, Jr., et al.
SUMMARY OF THE INVENTION Accordingly, one object of the present invention is to provide a preloaded electrical connector in which the likelihood of relative motion between the connector parts is virtually eliminated. In this regard, an aim of the invention is to provide an electrical connector of the foregoing type in which there is a metal-to-metal bottoming of the parts or components when mated so that little or no wear results and, as a result of the lack of relative movement, electrical discontinuities are avoided. It will be appreciated, that once the parts of an electrical connector have been coupled that they should not become inadvertently uncoupled, yet the connector should permit ready uncoupling when it is desired to separate the parts. Consequently, it is within the purview of the present invention to provide a connector that will withstand a high degree of vibration, large shock forces, and appreciable temperature gradients or changes.
Another object of the invention is to provide an electrical connector that will possess the above attributes, X
yet which will be relatively inexpensive to manufacture. In this regard, it is planned that a connector fabricated in accordance with the teachings of the present invention will cost little more than a conventional bayonettype connector. Also, it is within the contemplation of the invention to provide a connector that will be longlasting and exceedingly reliable during its entire life.
A further object is to provide an electrical connector that requires very little manual force to effect the coupling thereof. In this regard, the ramp grooves are configured or contoured so that most of the mating travel occurs before any appreciable amount of spring deflection occurs,
Yet another object of the invention is to provide a set of detent balls that automatically become effective to assist the spring washer in maintaining the connector in its coupled or mated condition, the detent balls being shifted into their latching condition near the end of the rotation of the coupling ring.
A further object is to provide an electrical connector that can be easily assembled, and also wherein precise dimensions and spacings need not be initially adhered to. More specifically, an aim of the invention is to provide a means by which the loading of the specially designed spring washer can be predetermined within desired limits during the assembling procedure, a retainer ring being threadedly positioned and secured in place to thereafter furnish the correct amount of spring loading during subsequent use of the connector.
Briefly, my invention comprises a spring washer having a tapered cross section that is progressively deflected, reaching a desired state of compression near the end of the coupling action. The requisite deflection occurs after a metal-to-metal bottoming of one connector component with respect to the other has been achieved. While a bayonet and ramp groove arrangement is used in effecting the coupling of the two connector components, the present invention avoids the need for offset pockets or notches at the closed ends of the grooves by reason of the retaining force exerted by the compressed spring washer, thereby assuring that the above-mentioned bottoming relationship is maintained. Provision is also made for assisting the action provided by the flexed spring washer, a plurality of ball detents being automatically shifted into an'interfering relationship so that they supplement the retentive action of the washer. By reason of the improved mechanical construction, electrical characteristics are also improved.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of my electrical connector when the parts are fully coupled together, a portion thereof being broken away in order to show to better advantage the connectors internal construction;
FIG. 2 is a fragmentary view corresponding generally to FIG. 1 but illustrating the parts prior to a complete mating thereof;
FIGS. 3 and 4 are sectional views taken in the direction of lines 3-3 and 4-4 of FIGS. 3 and 4, respectively, for the purpose of showing how the detent balls function;
FIG. 5 is a developed plan view of one of the ramp grooves formed in the coupling ring, the leftmost phantom outline of one of the bayonets or pins showing the entering of the bayonet or pin into the groove and the other phantom position illustrating the point in the bayonet travel where the spring washer starts to become compressed, and the solid or rightmost position of the bayonet illustrating the fully coupled condition of the connector components at which point the washer has become sufficiently deflected to assure retention of the connector parts in their coupled relation, and
FIG. 6 is a graphical representation illustrating a typical working range of the spring washer with percent spring force as the ordinate and percent spring deflection as the abscissa, the solid curve depicting a nominal value and the portions of the dash curves within the working range lower and upper acceptable limits.
DESCRIPTION OF THE PREFERRED EMBODIMENT An electrical connector exemplifying my invention is denoted in its entirety in FIG. 1 by the reference numeral 10. As is conventional, a connector of this type includes two components or halves l2 and 14. In the illustrated instance, the component 12 comprises a rigid shell 16 containing a rubber grommet 18, a rigid dielectric contact retainer 20, a rubber insert 22 and a rigid dielectric block 24 formed with a forwardly directed integral lip or rabbet 26, these members all being fixedly retained in the shell 16. The several members 18-24 encompass and hold in place any preferred number of socket contacts 28, the precise number depending upon the number of conductors or wires 30 to I be electrically connected. Although not a part of the invention, a cable clamp 32 has been pictured which encompasses the wires 30. The shell 16 is suggestively formed with external threads at 34 for the attachment of the protective shroud or sleeve 36 portion of the cable clamp 32. It will be perceived from FIGS. 1-4 that the shell 16 is formed with an outwardly projecting flange 38 thereon, serving a purpose later to be referred to. The flange 38 is formed with a peripheral or circumferential slot or groove 39.
Although the function thereof is not readily apparent at this stage of the description, it can be pointed out that a plurality of angularly spaced cylindrical holes 40 are also formed in the flange 38, extending from the right face of this flange to the above-mentioned groove 39. Actually, four such holes 40 will suffice and even three can be employed. Bowed in the direction of each hole 40 is a wave washer 42 or spring residing in the groove 39. A detent ball 44 is housed in each hole 40.
The detent balls 44, only one appearing in the drawings, are shifted into interfering positions, as will hereinafter become clearer, to assist in preventing inadvertent uncoupling of the connector halves or parts 12, 14.
Describing now the component or part 14, it will be noted that this half of the connector includes a shell 46 having therein a rubber insert 48 plus a dielectric contact retainer and grommet (not shown but corresponding generally to the members and 18, respectively). Projecting from the insert 48 is a number of pin contacts 50 that are cooperable or engageable with the previously mentioned socket contacts 28 belonging to the component 12, the block having appropriately spaced holes through which the pin contacts 50 extend when mated with the contacts 28. The left ends of the pin contacts 50 connect to a plurality of conductors or wires 52. To permit mounting of the component 14, the shell 46 may be provided with a flange 54 having suitable mounting holes 55 therein. The shell 46 has a number of radially projecting bayonets or pins 56 thereon for a purpose explained immediately below.
At this time, attention is called to a coupling ring 58 having a plurality of helical ramp grooves 60. Portions of one such groove 60 can be seen quite clearly in FIGS. 1 and 2, and the full groove (in developed form) in FIG. 5. As should also be evident from these three figures, one bayonet 56 extends into each ramp groove 60.
From FIGS. 1 and 2 it will be further discerned that the right end of the coupling ring 58 is formed with internal threads 62. Secured within the end of the coupling ring 58 by means of the threads 62 is a retainer appropriately secured in place so as to become an integral portion of the coupling ring 58. Various techniques can be resorted to in the securement of the retainer ring 64 so that it is not thereafter rotatable with respect to the coupling ring 58. For instance, the retainer ring 64 can be staked or welded. Although the way it is held stationary is relatively unimportant to a practicing of the invention, it is imperative that its properly adjusted position be maintained. In other words, the retainer ring 64 is not secured in place until a certain longitudinal space or distance is provided between the retainer ring 64, which serves as an inwardly projecting integral flange, and the earlier mentioned outwardly projecting flange 38 on the shell 16 of the component 12.
Performing a very important role in the practicing of the invention is a specially configured spring washer 68. The thickness, material and diameter determine the ring 64, the ring 64 having external threads 66 that permit its axial positioning within the coupling ring 58 to whatever extent is necessary. It will become clearer as the description progresses that the retainer ring 64 is initially positioned properly during assembly and then is annular, has a thicker outside diameter and a thinner inside diameter. Furthermore, the inner periphery of the washer 68 is offset to the left of the outer periphery, as can be pictorially appreciated from FIGS. 1 and 2. It is also thought that the advantages to be derived from the incorporating of such a washer in the connector 10 can be graphically understood and interpreted from FIG. 6. From the solid curve labeled 70 in FIG. 6 it will be noted that a considerable amount of spring force is needed to provide the initial deformation of the washer 68 and similarly a large change in force is needed to fully deform the washer up to about 50 percent of its total deflection capability. However, there is a working range, typically between 0.008 and 0.015 inch of deformation (for one specific model) where very little additional spring force is needed to effect the deformation from the 0.008 inch condition to the 0.0l5 inch condition. Owing to the fact that these figures depend upon connector dimensions, percentages have been given in FIGS. 5 and 6, and even these percentage values depend upon specific design characteristics and reliability factors. The dashed curves 70a and 70b, it might be explained, are intended to depict typical lower and upper acceptable limits, the curve 70 actually representing a nominal value therebetween; here again, though, the limits are only illustrative, demonstrating mainly that limits can be easily obtained. The advantages to be derived from this working range probably will be better understood as the description progresses, especially when considering the manner in which my connector 10 is coupled together.
As can be seen from FIGS. 1-4, there is a detent ring 72 having an outer key 74 integrally formed thereon which projects radially into a longitudinally directed keyway 76 formed in the interior of the coupling ring 58. As its name implies, the function of the ring 72 is to coact with the detent balls 44; therefore, a plurality of detent pockets 78, the number corresponding to the number of balls 44, are angularly disposed around the ring 72. However, the detent pockets 78 are of smaller diameter than the balls 44 so that the balls 44 cannot be fully received therein. Comparing the position of the particular detent ball 44 appearing in FIG. 2 with that appearing in FIG. 1 will illustrate that the shifting of the detent balls 44 is such as to only cause segmental portions thereof to be received in the pockets 'or passages 78; they never fully move into the pockets 78.
In assembling the electrical connector 10, it is to be understood that the detent ring 72 is inserted within the coupling ring 58, the insertion being via the right end. Of course, the wave washer 42 and detent ball 44 are in place prior to inserting the ring 72. The wave washer 42 is angularly positioned so that its crests properly bear against the several balls 44 for the purpose of biasing the balls to the right as viewed in FIGS. 1 and 2. The spring washer 68 is next inserted so that one side con fronts or faces the detent ring 72. It is then that the connector is in readiness for the initial threaded advancement of the retainer 64 inwardly.
However, it is planned that a gauge tool be substituted for the shell 46 during the assembling procedure. The gauge tool would correspond generally in appearance to the shell 46. However, it differs dimensionally inasmuch as the distance from the left side of the pin or bayonet 56 appearing in FIG. 1 to the right end of the shell 46 is somewhat less than the depicted distance of the pin 56 with respect to the right end of the shell 46. More specifically, the gauge tool would be foreshortened so as to compensate for the amount necessary to bring the washer 68 into its working range, as pictorially represented in FIG. 5 and graphically in FIG. 6. The alluded to working range has been denoted in FIG. 5 by the amount of advancement of the bayonet or pin 56 from its intermediate position (shown in phantom outline) to the right hand position (shownin solid outline), the right hand solid line position denoting the point where the coupling of the connector 10 is fully completed. By indicating the working range in FIG. 6 on a percentage basis, as far as the deflection of the washer 68 is concerned, is believed to present a more generalized condition than employing typical mil figures.
If the retainer 64 is now advanced so that it just contacts the spring washer 68, then when the regular connector component or half 14 is employed, the spring washer 68 will be compressed or deflected sufficiently so as to bring the requisite percent deflection within the working range illustrated in FIG. 6. From FIG. 6 it will be noted that a considerable percentage variation of linear deflection is permissible without going below or above the allowable working range limits. Assuming for the sake of discussion that any force over 50 percent will be adequate to maintain the connector 10 coupled, it can be seen from FIG. 6 that the percent force for the working range is well above the 50 percent level, actually being approximately 80 percent which provides an excellent margin of safety under virtually all environmental conditions.
Consequently, a considerable amount of allowance is provided for the wear of the various bayonets or pins 56 with respect to the sides of the several ramp grooves 60. Further, it will be appreciated that the mode of assembly described above compensates for any geometric variations in the thickness and spacing of the various parts such as the pins 56, the thickness of the flange 38 and the detent ring 72. It will also be recognized that the inaccuracies or variations resulting from the machining of the ramp grooves 60 and/or the locations of the pins or bayonets 56 are automatically compensated for by reason of the assembling procedure just described. This all is realized by virtue of the positioning of the retainer 64 with the gauge tool in place. After the retainer 64.has been properly located, then its securement, such as by staking or welding (as previously mentioned), will assure that the position of the retainer 64 is maintained,
It is important to appreciate that the same deforma tion or deflection of the spring 68 that is initially realized during assembly will be repeatedly obtained each time that the components 12 and 14 are coupled together. The working range allows for a considerable amount of bayonet and groove wear. It will also be noted that not only is the same spring deformation realized, but the metal-to-metal bottoming of the shell 16 againstthe shell 46 is re-established each time.
By proper machining of the keyway 76 in the coupling ring 58, it follows that the detent ring 72can be angularly oriented so that the pockets or openings 78 will be in alignment with the various detent balls 44 each time the parts 12, 14 are coupled together. Consequently, when the coupling ring 58 is rotated or twisted to couple the components 12, 14 together, the detent balls 44 will be urged or shifted (under the influence of the wave washer or spring 42) to effect a segmental engagement thereof with the pockets 78. It will be recalled that the pockets 7 8 are of lesser diameter than the diameter of the detent balls 44, so the relationship appearing in FIG. I is always established each time the components 12 and 14 are mated.
As can be understood from FIG. 5, it is only when the bayonets 56 approach the closed ends of their respective helical ramp grooves that the spring washer 68 is compressed or deflected from its preloaded state of deformation. Up to this particular point, which is represented by the right hand dotted position of the particular bayonet 56 in FIG. 6, there is little resistance to the mating or coupling action. In other words, the camming performed by one side of each helical groove 60 simply acts against the bayonets 56 to pull or force the shell 46 into its mating relationship with the'shell 16. By correlating the point of compression or deflection of the washer 68 with the approach of the bayonets 56 toward the end of their respective grooves 60, the slope of the grooves 60 may be lessened or made more gradual so that a greater mechanical advantage is realized. Stated somewhat differently, the washer 68 requires only a few thousandths of compression or flattening in order to become effective and this need only be obtained near the ends of the grooves 60 where the slope is deliberately decreased, thereby minimizing the amount of manual effort required to rotate the coupling ring 58 under these terminating conditions.
When uncoupling or disconnecting the connector 10, a reverse rotation of the coupling ring 58 moves the detent ring 72 so as to force the partially received detent balls 44 out of the pockets 78. However, until some manual twisting effort is applied to the coupling ring 58, the detent balls 44, owing to the interfering relationship they have, further assist in the prevention of unwanted separation of the components 12 and 14. Once out of the pockets 78, the detent balls 44 simply roll against the left face of the ring 72 in a'reverse fashion from that in which they roll when the coupling is being effected. The washer 68 expands from its compressed state during this happening until it reaches its initial degree of compression determined by the proper positioning and securement of the retainer ring 64, which functions as an inwardly projecting flange as previously pointed out, during assembly,
Recapitulating, the space or distance between the flanges 38 and 64 is varied, being decreased during the coupling of the connector and increased during the uncoupling thereof. However, when fully coupled, the shell 16 will always bottom against the shell 46, more specifically the flange 38 abuts the right end of the shell 46 as is clearly evident in FIG. 1. Also, the detent or notch portions previously provided in the prior art arrangements at the closed end of the helical or ramp grooves are not needed. Thus, there is no unwanted backing off" by virtue of the detent notches previously employed at the ends of the ramp grooves. Consequently, my connector 10 resists vibration, shock and thermal gradients much more effectively than those connectors relying upon detent notches at the ends of the ramp grooves. Also, any deleterious effect attributal to wear of the bayonets 56 or the walls of the grooves 60 is minimized because of the preloading.
1. An electrical connector comprising first and second components, each having interengageable contact means, coupling means for advancing said first component with respect to said second component to cause a portion of said first component to abut a portion of said second component and to cause engagement of said respective contact means, and spring washer means interposed between a portion of said coupling means and another portion of said first component which spring means is deflected solely by a predetermined decrease in the distance between said last-mentioned portions occurring only after said first-mentioned portions abut each other, said spring washer meanshaving an undeflected thickness not greater than the distance between said last-mentioned portions at the time said firstmentioned portions abut each other.
2. The electrical connector defined in claim 1 in which said coupling means is rotatable to advance said first component with respect to said second component, a detent ring rotatable with said coupling means having an axially directed hole therein, and a ball shiftable partially into said hole when said first and second components are fully coupled together.
3. The electrical connector defined in claim 2 in which said portion of said coupling means includes a retainer ring rotatable with both said coupling means and said detent ring, said spring washer means including a deformable washer member disposed between said rings.
4. An electrical connector comprising first and second components, each having interengageable contact means, a rotatable coupling ring for advancing said first component with respect to said second component to cause a portion of said first component to bottom against a portion of said second component when said coupling ring is in one rotative position and to also produce engagement of said respective contact means when in said one rotative position, a threaded retainer ring rotatable with said coupling ring, and a deformable spring washer engageable by said retainer ring to cause deflection of said spring washer only between said one rotative position of said coupling ring and a second rotative position of said coupling ring which produces a complete coupling of said first and second components, the axial position of said retainer ring predetermining the amount of said spring deflection.
5. The electrical connector defined in claim 4 including outwardly projecting bayonet means mounted on said first component, said coupling ring having an internal ramp groove receiving said bayonet means, saidretainer ring being fixedly positioned in a spaced relationship with said ramp groove so as to provide said predetermined amount of deflection of said spring washer when said coupling ring has been rotated between its said rotative positions.
6. The electrical connector defined in claim 5 including outwardly directed flange means on said second component and detent means disposed axially between said outwardly porjecting means and said spring washer, whereby said detent means assists said spring washer in retaining said first and second components in their coupled condition when said coupling ring has been rotated into said second position.
7. An electrical connector comprising first and second shells of a size such that an end portion of said second shell fits in an end portion of said first shell, first contact means contained in said first shell, second contact means contained in said second shell, said second shell having an outwardly projecting flange engageable by the end portion of said first shell when said first and second contact means are mated, a coupling ring having an inwardly projecting flange, interengaging bayonet and ramp groove means on said first shell and said coupling ring for advancing said first shell in a direction to cause its said end portion to abut said outwardly projecting flange to reduce the axial spacing between said flanges, a spring washer disposed in said space'and confronting said inwardly projecting flange, and means positioned in said space between said outwardly projecting flange and said washer for transmitting a compres sive force against said washer to partially flatten said washer against said inwardly projecting flange only after the said end portion of said first shell abuts said outwardly projecting flange.
8. The electrical connector defined in claim 7 in which said means includesa detent ring confronting the other side of said spring washer, said detent ring being longitudinally keyed to said coupling ring and having at least one pocket therein facing away from said washer, said outwardly projecting flange having at least one recess therein, a detent ball carried in each of said recesses of a size so as to only partially be received in said pocket when rotation of said coupling ring has moved said pocket into angular alignment with said recess and the detent ball contained therein, and resilient means for urging said detent ball in the direction of said pocket.
9. The electrical connector defined in claim 7 in which said inwardly projecting flange is threadedly received in said coupling ring.
10. The electrical connector defined in claim 9 in which said inwardly projecting flange is fixedly secured within said coupling ring at the proper location to preload said spring washer.
' 11. An electrical connector comprising first and second components, each having interengageable contact means, coupling means for advancing said first component with respect to said second component to cause a portion of said first component to abut a portion of said second component and to cause engagement of said respective'contact means, and spring washer means interposed between a portion of said coupling means and another portion of said first component which spring means is deflected by a decrease in the distance between said last-mentioned portions after said firstmentioned portions abut each other, said spring washer means being preloaded and having a tapered cross section.
12. The electrical connector defined in claim 11 in which said washer has a thicker outside diameter and a thinner inside diameter.
13. The electrical connector defined in claim 11 in which said spring washer means constitutes an annular washer having a thicker outer diameter and a thinner inner diameter.
14. The electrical connector defined in claim 13 including detent means for assisting said annular spring washer in the retention of said components in their coupled relationship.
15. The electrical connector defined in claim 14 in which said detent means includes a ball shiftable into a retentive position.
16. An electrical connector comprising first and second shells of a size such that an end portion of said second shell fits in an end portion of said'first shell, first contact means contained in said first shell, second contact means contained in said second shell, said second shell having an outwardly projecting flange engageable by the end portion of said first shell when said first and second contact means are mated, a coupling ring having an inwardly projecting flange threadedly received therein, interengaging bayonet and ramp groove means on said first shell and said coupling ring for advancing said first shell in a direction to cause its said end portion to abut said outwardly projecting flange to reduce the axial spacing between said flanges, a spring washer having a tapered cross section disposed in said space and confronting said inwardly projecting flange, said inwardly projecting flange being fixedly secured within said coupling ring at the proper location to preload said spring washer, and means positioned in said space between said outwardly projecting flange and said washer for transmitting a compressive force against said washer to partially flatten said washer against said inwardly projecting flange.
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