Patent Publication Number: US-3880490-A

Title: Means and method for protecting and spacing clamped insulated wires

Description:
United States Patent 1191 Belmont 1 1 MEANS AND METHOD FOR PROTECTING AND SPACING CLAMPED INSULATED WIRES [75] Inventor: Edward A. Belmont. Burbank. Calif.  
 [73] Assignee: Lockheed Aircraft Corporation.  
 Burbank. Calif.  
 [22] Filed: Oct. 1, 1973 [21] Appl. No.: 402.184  
 [52] US. Cl. 339/103 B: 174/135 [51] Int. Cl. H01r 13/58 [58] Field of Search 24/1226; 285/137: 174/1352339/15.16.103. 107. 206-210. 213. 273  
 [56] References Cited UNITED STATES PATENTS 2.511.037 6/1950 Bedoiseau 339/103 R 2,959,436 11/1960 Duda 24/1226 X 3.123.879 3/1964 Boduroff et a1. 339/103 M X 3.135.535 6/1964 Shepard 339/103 B UX 3.333.232 7/1967 Patton 339/182 R 3.633.265 1/1972 Lyashenko et al..... 24/1226 X 3.794.959 2/1974 Kamolz 339/103 M 3.831.133 8/1974 Grundfest 339/210 M FOREIGN PATENTS OR APPLICATIONS 1.349.299 12/1963 France 174/135 1 1 Apr. 29, 1975 OTHER PUBLICATIONS Lyon. Cable Grommet.&#34; IBM Tech. Disc. Bulletin. February 1959. Vol. 1. No. 5. page 35.  
 Primary E.\&#39;uminw&#39;Roy D. Frazier Assistant E.\&#39;amim&#39;r--Lawrence .1. Staab Attorney. Agent. or Firm-Billy G. C orber: Frank L. Zugelter: Lowell G. Turner [57 ABSTRACT A plurality of concentrically oriented and spaced bushings mounted on and about corresponding circu- Iarly disposed sets or arrays of insulated wires or electrical conductors. and a clamp securing such plurality adjacent to a connector. Each bushing includes a helically fashioned slit longitudinally from its one end to its other end to facilitate assembly thereof to a particular array or set of conductors. The array of conductors extends from a receptacle or plug. and. unless properly supported in clamped position. are subject to mis-grouping or poor grouping. or to side strain which degrades the environmental seal for the connector. This particular clamped assembly provides an excellent grouping. relieves the side strain. and prevents sideloading of the wires at such seal of the receptacle or plug.  
 18 C1aims.&#39;4 Drawing Figures PATENTEmPRzsms m u n y??? m 1.. M M M m m e 1 ,1 v 2 H mm m M FIG. 5  
 FIG. 4  
 MEANS AND METHOD FOR PROTECTING AND SPACING CLAMPED INSULATED WIRES STATEMENT OF GOVERNMENT INTEREST The invention herein described was made in the course of or under a contract or subcontract thereunder, with the Department of the Navy.  
 BACKGROUND OF THE INVENTION 1. Field of the Invention The field of art to which the invention is most likely to pertain is located in a class of devices generally relating to strain relief clamping devices. Class 339. Electrical Connectors. U.S. Patent Office Classification. may be the applicable general area of art in which the claimed subject matter would be classified.  
 2. The Prior Art 1 Examples of prior art devices in the arts to which this invention most likely pertains are U.S. Pat. No. 309.267; 1.089.642; 2.963.536; 3.009.129; 3.026.495: 3.027.4l9; 3.266.009; 3.402.382; and 3.445.805.  
 PROBLEMS IN THE PRIOR ART In the assembly of strain relief clamping devices to insulated wires or conductors emanating from electrical connector components such as contacts of plugs and receptacles. a major difficulty has been the lack of manufacturing control. For example. the application of v elastic materials. by threading and interweaving strips of. say. rubber. around. through or about the wires adjacent to the plug or receptacle. in order to maintain perpendicularity of wires to the plug or receptacle. after which a clamp is secured thereto. varies from operator to operator, and in assembly time. These uncontrollable factors are compounded by the difficulties encountered in the installation of the elastic material and the clamp upon short clamp connectors. In many instances, the wires. emanating in circular array from the plug or receptacle. become grouped with.each other, in the middle or in arcuate fashion. When clamping them so grouped. a sideload on the wires occurs. The result is a degrading of the plug or receptacle by opening the plug or receptacle wire seal environmental grommet. Such opening exposes the electrical contacts in the connector to the damaging effects of moisture. This occurs even with the conventional threading or interweaving pattern utilized by the operator.  
  In regard to a bushing. in or outside of the connector component, and having individual holes. with a cut made from the bushings periphery to each hole to eliminate a threading technique. assembly nevertheless has been time consuming and subject to variation in wire placement in such individual holes.  
  Again. in a single wrap method, wherein a long strip of rubber has been used to wrap the center wires together and then continue to be wound outwardly from, the center to encircle each array of wires. with cutoff nates the problems encountered in the single bushing configuration. I  
  This invention overcomes these attendant problems in the known; and conventional assembly techniques mentioned above aswell as others, while providing a ment of elements achieving the desired objectives of not sideloading the wires or contacts within plugs or receptacles and maintaining the corresponding seals.  
 SUMMARY OF THE INVENTION This invention generally relates to strain relief clamps. and in particular is directed to such an article and its adaptability to electrical connectors.  
  An object of this invention is to prevent sideloading of wires at a connector environmental grommet or seal so as to eliminate an open grommet or seal and damage caused by moisture moving into such an environment and the connector contact.  
  Another object of this invention is to relieve strain. broken wires. and to simplify the assembly for achieving such a result.  
  Another object of this invention is to reduce and control the time of installation for a strain relief article to a plug or receptacle. thereby obtaining control in manufacture while reducing costs. providing a more efficient. less complicated moisture proof connection. and achieving a simply-assembled strain relief clamp with a high factor of, reliability.  
 Yet another object of this invention is to space and protect electrical wires which are terminated in connectors (plug or receptacle) without degrading the environmental wire seal on the connector.  
 . Stillanother object of the invention is to facilitate the assembly of a strain relief clamp.  
  These and other objects and advantages will become more apparent by a full and complete reading of the following description. appended claims thereto. and the accompanying drawing comprising one (I sheet.  
 DESCRIPTION OF THE DRAWING FIG. I is a perspective view of the invention as adapted to an electrical connector (partly broken away).  
 &#39; FIG. 2 is an end view of&#39; FIG. 1. somewhat modified.  
 FIG. 3 is a view taken on line 3-3 of FIG. 2.  
  FIG. 4 is a perspective view of a bushing utilized in the subject matter of the invention.  
 DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing in which reference I characters therein refer to like numerals hereinafter.  
 which need not be described hereinafter except to the following extent for an understanding of the invention.  
 The plug 10 comprises a sleeve 12 about which a rotatv able circumscribing metal ring 14 is mounted. The ring novel, efficierityand &#34;simpler combination and arrange l4is reduced as at 16. The end 18 of the sleeve 12 is provided with multi-contact holes (not shown) of the type whereby a multi-contact plug assembly (not shown) is engageable in complementary fashion to the plug 10, i .e., to the contact holes in the face of the end l8 of the sleeve 12.  
  The other end of the sleeve 12 is threaded as at 20 for mounting a backshell clamping element 22. The element 22 is conventional and well known, and comprises an internally threaded collar 24 for securement posed sets or arrays 44, 45, 46,  
 to&#39;the threaded sleeve 12. An environmental grommet or seal 26 is disposed across such end of the sleeve I2 out of which come a plurality of insulated wires 28 in circular array and which wires are operatively connected to the multi-contact hole configurations at the end 18 of the sleeve 12. A circular retaining member 30 ,is rotatably mounted in the collar 24 by means of an annular flange riding in a corresponding circumferential slot provided in the collar 24, and as shown in the brokenraway portion of the perspective of FIG. I. The  
 30, and its accessory elements 32, 34, 36, 37 and 38 constitute a known and conventional component mounted on a known and conventional electrical connector in a known fashion.  
 The following description pertains to the particular subject&#39;matter of this invention. The bushing assembly comprises a plurality of concentricallyoriented and spaced bushings 40, 41, 42, These bushings are mounted on and about corresponding circularly disrespectively. of electrical conductors or wires 48. As shown in FIGS. 2 and 3, the bushing 40 envelops, encircles. or surrounds the innermost set 44 (only one conductor 48 in this illustration, but not necessarily limited thereto); The bushing 41 is mounted about the wire set 45 and is concentrically oriented to the bushing 40. The wire set 45 is the next to the innermost set 44 and is spaced outwardly therefrom. The bushing 42 is mounted about the wire set 46 which is spaced outwardly from the wire set 45, and is concentrically oriented to the bushing 41. And so forth. For each set of wires, a bushing spaces such set from a wire set disposed in a separate or different circular or other array, and the bushings are in concentric orientation relative to each other.  
 It should now be apparent that a set of wires may comprise one or more wires. grouped generally in parallel fashion to each other and in a circular array, and that as a practical matter for utilization purposes, each wire is insulated from another wire in the same set. It should be understood, however, that the invention is not necessarily limited to electrical conductors,&#34;but may also be utilized in other applications as the need may warrant. In other words, the conductors are not necessarily limited to electrical conductors or insulated wires. i  
 In regard to adaptation of the invention to a plug 10,  
  the plurality of concentrically oriented bushings 40, 41,  
 42, are disposed adjacent to the plug 10 and in a position thereto so that the clamping bars 34 face andbear directly against the outermost exteriorly mounted bushing. Thus, tightening of the screws 38 provides for a secure disposition of the bushing assembly 35in cooperative relationship with the plug 10.  
  It now becomes evident that&#39;regardless of the number of wires 48 in each set, or the particular position of each wire 48 to another wire 48 in their &#39;own array, such as the arcuate spacing therebetween, the assembly of the bushings andthe clamping means 34 thereto provides for a constantlyimposed force on each of such wires and the bushings. Such force is established by the compression of the clamping means 34 about the bushing encircling the arrays or sets of wires 46. The thickness of each bushing may be dictated by the radial or other distance existing between each circular or other array ofwires. In the case of adapting the described subject matter to the plug 10, such distance may be measured across the dimension or diameter of the environmental seal 26 or sleeve 12 of the plug 10. The advantage of eliminating a sideloading on the seal 26 or each of the wires themselves is achieved.  
  To facilitate the application or assembly of each bushing 40, 41, 42, to its particular array or set of wires 44, 45, 46, a helical slit 50 (FIG. 4) is provided in a longitudinal manner in each bushing. Thus, the operator on the assembly line, rather than threading a bushing onto an array of wires, or vice versa, can  
 quickly manipulate the bushing onto such array by opening the slitted bushing and slipping it thereon at the location for the arrangement of the bushings and wire sets.  
  The helical natureof the slit 50 assures the operator that one or-more wires in a given set which is enveloped by its bushing does not squeeze out of its set. I.e., upon clamping the bushing assembly 35, were the slit 50 provided in the bushing 40, 41, 42, to be parallel with its longitudinal axis, the compression on the bushing enveloping the given set could cause one or more of the wires therein to squeeze through the slit 50 to become erroneously grouped with a different set of wires and thereby develop an undue or undesired strain on wire or on a plug 10 adapted to the bushing assembly 35.  
  The assembly of the subject matter of the invention. may be considered in two manners. In the case of employing the invention with a connector 10, the smallest bushing 40 is first slipped onto or about the innermost wire 48 or set 44 of the plurality of wires extending from the connector I0. The next largest bushing 41 is then slipped onto or about the immediately next adjacent set of wires 45 to a group same in proper position relative to the first set 44. And so forth. The slipping-on step for each bushing to a set may be done either by slipping each bushing on in a concentric fashion to each other, or by slipping one or more of the bushings onto their respective sets randomly, along the length of the plurality of wires and then pushing all of the bushings&#39;towards each other to a concentrically oriented assembly 35. This assembly is positioned within the confines of the clamping means 34 connected to the connector l0, and thereafter the screws 38 tightened.  
  The slipping-on step itself may occur directly about the plurality&#39;of&#39;wires to which the bushings are to be mounted, or the bushings may be slipped on from a terminus for all the wires in the plurality. In this latter in stance,a slit50 is&#39;not required. On the other hand, the  
 outermost disposed bushing need not include a slit 50 where one or more of the other and inwardly disposed bus&#39;hingsinclude a slit 50. I  
  utilized. In other words, elements 32, 30. and connector I 10-are fit required. The clamping itself, of course, oc-  
 . Pursuant to the requirements of the patent statutes.  
 the principle of this invention has been explained and exemplified in a mannerso that it can be readily practiced by those skilled in the art to which itpertains. or with which it is most nearly connected. such exemplification including what is presently considered to represent the best embodiment of the invention. However. it should be clearly understood that the above description and illustrations-are not intended to unduly limit the scope of the appended claims. but that therefrom the invention may be practiced otherwise than as specifically described and exemplified herein. by those skilled in the art. and having the benefit of this disclosure.  
 Therefore. what 1 claim as patentably novel is:  
  l. The combination with a plurality of sets of circularly arranged conductors. of a circular array of concentrically oriented flexible bushings having substantially constant cross-sections. mounted in spaced relation about said conductors and grouping said sets in spaced relation to each other. and a clamp mounted the exteriorly disposed one of said bushings for maintaing the relative positions of said conductors.  
  2. The combination of claim 1 wherein at least some of said bushings include a slit along their respective lengths.  
  3. The combination with a plurality of sets of circularly arranged conductors. of a circular array of concentrically oriented bushings mounted about said conductors to group said sets in spaced relation to each other. at least some of said bushings including a slit along their respective lengths. said slit being helical with respect to the longitudinal axis of its bushing. and a clamp mounted on the exteriorly disposed one of said bushings for maintaining the relative positions of said conductors.  
  4. The combination with a plurality of sets of circularly arranged conductors, of a circular array of concentrically oriented bushings mounted about said conductors to group said sets in spaced relation to each other, each of said bushings including a slit along its length and a clamp mounted on the exteriorly disposed one of said bushings for maintaining the relative positions of said conductors.  
  5. The combination of claim 4 wherein the nature of said slit is helical with respect to the longitudinal axis of its bushing.  
  6. The combination with a plurality of sets of circularly arranged conductors or the like and with a clamping means. of a bushing assembly comprising at least two concentrically oriented flexible bushings mounted about said conductors or the like to group said sets in spaced relation to each other, at least one of said bushingsincluding means longitudinally thereof to accommodate the entrance of conductors therethrough,  
 said clamping means being mounted on the most exteriorly disposed one of said bushings for maintaining the relative positions of said conductors.  
  6 7. The combination of a connector from which a plurality of conductors extends in a plurality of sets and from which aclamping means cooperatively extends longitudinally. with a plurality of concentrically ori- &#39;ented bushings mounted about said plurality of sets of conductors and incorporating slit&#39;means therethrough to accommodate the side entrance of said conductors into the interior of the respective said bushings.  
 each of said bushings enveloping one of said sets.  
 said clamping means bearing against the outermost I concentrically oriented one of said plurality of bushings.  
 whereby sideloading of said connector is eliminated.  
  8. Thecombination of a connector from which a plurality of conductors extends in a plurality of sets and from which a clamp means cooperatively extends longitudinally. with a plurality of concentrically oriented bushings mounted about said plurality of sets of conductors. each said bushing enveloping one of said sets and at least some of said bushings including a helical 3 slit along their respective lengths and with respect to their longitudinal axes.  
 I said clamping means bearing against the outermost concentrically oriented one of said plurality of bushings.  
 whereby sideloading of said connector is eliminated.  
  9. The combination of a connector from which a plurality of conductors extends in a plurality of sets and from which a clamp means cooperatively extends longitudinally. with a plurality of concentrically oriented bushings mounted about said plurality of sets of conductors. each said bushing enveloping one of said sets and including a slit along its length and with respect to its longitudinal axis.  
 5 said clamping means bearing against the outermost concentrically oriented one of said plurality of bushings.  
  whereby sideloading of said connector is eliminated. 0 10. The combination of claim 9 wherein the nature of said slit is helical with respect to the longitudinal axis of its bushing.  
  11. A method for assembling and securing a plurality of sets of conductors or the like comprising in combinatron,  
 encircling each of a plurality of sets of conductors in circular array with a flexible bushing of substantially constant cross section,  
 concentrically orienting the bushings mounted about said sets of conductors. and  
 clamping such bushings together.  
  12. The method of claim 11 including the step of slitting some of said bushings along their respective lengths.  
  13. A method for assembling and securing a plurality of sets of conductors or the like comprising in combination.  
 providing a plurality of bushings and helically slitting some of the same along their respective lengths with respect to their longitudinal axes,  
 60 encircling each of a plurality of sets of connectors in circular array with a bushing, concentrically orienting the bushing mounted about said set of conductors, and 65 clamping such bushings together.  
  14. A method for assembling and securing a plurality of sets of conductors or the like comprising in combination,  
  7 providing a plurality of bushings and slitting each of the same along their respective lengths encircling each of a plurality of sets of conductors in circular array with a bushing.  
  concentrically orienting the bushings mounted about said set of conductors. and  
  clamping such bushings together.  
  15. The method of claim 14 wherein said slitting step results in a helical slit with respect to the longitudinal axis of its bushing. l g  
  16. A method for assembling and securing a plurality of sets of conductors or the like comprising in combination.  
 providing a plurality of bushings.  
 slitting some of the bushings helically along their reof conductors emanate and to which a cooperating means is longitudinally mounted for clamping thereto. and I I clamping such bushings together. 17. A method for assembling and securing a plurality of sets of conductors or the like comprising in combina+ providing a plurality of bushings, slitting each of the bushings along its length, encircling each of a plurality of sets of conductors in circular array with a bushing, concentrically orienting the bushings said set of conductors. positioning the plurality of concentrically oriented bushings enveloping the sets of conductors adjacent to a connector component from which the sets a of conductors emanate and to which a cooperating means is longitudinally -mounted for clamping thereto. and clamping such bushings together. v 18. The method of claim 17 wherein said slitting step results in a helical slit with respect to the longitudinal axis of its bushing. I  
 mounted about