US3622942A

US3622942A - Strain relief

Info

Publication number: US3622942A
Application number: US32162A
Authority: US
Inventors: Edward F Rynk
Original assignee: Thomas and Betts Corp
Current assignee: ABB Installation Products Inc
Priority date: 1970-04-27
Filing date: 1970-04-27
Publication date: 1971-11-23
Anticipated expiration: 1988-11-23

Abstract

The invention is directed to an improved unitary, integral, detachable strain relief. At least one generally arcuate clamping arm is resiliently coupled to a generally tubular body member adapted to be detachably secured about the outer surface of a conector or similar article. Strap receiving means project outwardly from its associated clamping arm to at least partially retain therein a strap or band disposed thereabout to secure the clamping arm to a cable or a plurality of insulated electrical wires positioned immediately adjacent thereto and extending outwardly from the connector.

Description

United States Patent [72] lnventor Edward F. Rynk Linden, NJ. 21 1 Appl. No. 32,162 {22] Filed Apr. 27, 1970 [45] Patented Nov. 23. 1971 [73] Assignee Thomas & Betts Corporation Elizabeth, NJ.

[54] STRAIN RELIEF 6 Claims, 11 Drawing Figs.

[52] US. Cl 339/107 [51] Int. Cl 1101! 13/58 [50] Field ofSearch 339/103, 104, 107, 62, 206, 116, 208, 101

[56] References Cited UNITED STATES PATENTS 1.292.911 1/1919 Stacey 339/103 C 2,830,282 4/1958 Swanetal 3,422,392 1/1969 Woods Primary ExaminerRichard E. Moore A!!0rneyDavid Teschner PATENTEDunv 2 3 an SHEET 1 OF 2 INVIfN'IUR EDWARD F RYNK ATTORNEY PATENTEDunv 2 3 1911 SHEET 2 OF 2 ATTORNEY STRAIN RELIEF BACKGROUND OF THE INVENTION 1. Field of the Invention The invention is directed to the field of strain relief devices, and principally to unitary, integral strain relief devices detachably connectable to an electrical connector or similar article.

2. Description of the Prior Art Strain relief devices according to the prior art generally comprised a plurality of discrete components requiring separate-means for coupling the components one to another and to the cable or similar item and connector about which said strain relief is to be secured. In practice, the individual components comprising such device were required to be positioned and maintained in proper relation relative to the article about which the device was to be secured, prior to the disposition and tightening thereabout of a strap or other similar securing means. Such operation was generally awkward, timeconsuming and uneconomical. Additionally, the separate components were subject to loss or misplacement, prior to assembly, further increasing the cost thereof. Commonly employed strain reliefs according to the prior art were also formed of generally rigid metallic material wherein filler means such as tape or other similar wrapping material was required to be wrapped around that portion of the insulated electrical conductors or electrical cable immediately adjacent the cable clamping portion of the strain relief in an attempt to compensate for varying diameter wire bundles about which the strain relief was to be secured, and to protect the relatively vulnerable electrical insulating material covering said conductors from the generally sharp edges of the clamping portion of the strain relief. I

SUMMARY OF THE INVENTION:

The invention is directed to an improved strain relief device which overcomes the problems noted above with respect to prior art devices by providing a unitary, integral, detachable strain relief device which is simpler, less expensive, safer, and more efficient than such devices. Resiliently coupled to a generally tubular body member and integral therewith, is preferably a pair of generally arcuate clamping arms, the inner generally concave surfaces of which define a substantially annular, variable cable receiving cavity. The inner surface of the body member may be threaded or have disposed thereon other similar projecting portions to permit said member to be detachably secured and tightened about the externally threaded portion of an electrical connector or the like. The body member may be comprised of a pair of generally arcuate members hingedly coupled together by an integral web portion therebetween. A raised portion projecting outwardly from the clamping arm of the strain relief device provides strap receiving means and may be either apertured or formed into a hook like member to receive and at least partially restrain therein a strap or similar item disposed thereabout for securing the clamping arms about an electrical cable or plurality of insulated electrical conductors extending outwardly from the connector. A longitudinally aligned recess may be provided in the outer surface of the body member wherein the body member may be conveniently parted along the recess permitting the device to be readily-disposed about a preexisting connected cable or conductor bundle. It is therefore an object of this invention to provide an improved strain relief device.

It is another object of this invention to provide an improved unitary, integral strain relief device for insulated electrical conductors or the like.

It is a further object of this invention to provide an improved strain relief device detachably connectable to the outer surface of a connector or similar item.

It is still another object of this invention to provide an improved strain relief device detachably securable about a connector or similar item and a plurality of electrical conductors or the like extending therefrom.

It is still a further object of this invention to provide an improved unitary, integral strain relief device having a conveniently separable body portion for positioning said device about a cable or plurality of electrical conductors previously terminated to a connector or the like.

Other objects and features of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawings, which disclose, by way of example, the principle of the invention and the best mode which has been contemplated for carrying it out.

BRIEF DESCRIPTION OF THE DRAWINGS In the Drawings FIG. 1 is a side view of a strain relief device constructed in accordance with the concepts of the invention.

FIG. 2 is a side view of the device of FIG. 1 assembled about a plurality of electrical conductors.

FIG. 3 is a side view of another embodiment of a strain relief device constructed in accordance with the concepts of the invention.

FIG. 4 is a side elevation view of another embodiment of a strain relief device constructed in accordance with the concepts of the invention.

FIG. 5 is a side elevation view of the device of FIG. 4 assembled about a plurality of electrical conductors.

FIG. 6 is a side elevation view of still another embodiment of a strain relief device constructed in accordance with the concepts of the invention.

FIG. 7 is a front elevation view of still a further embodiment of a strain relief device constructed in accordance with the concepts of the invention.

FIG. 8 is a side elevation view of still another embodiment of a strain relief device constructed in accordance with the concepts of the invention.

FIG. 9 is a perspective view of the strain relief device of FIG. 8.

FIG. 10 is a rear elevation view of still another embodiment of a strain'relief device constructed in accordance with the concepts of the invention.

FIG. 11 is a side elevation view of the strain relief device of FIG. 10.

Similar elements are given similar reference characters in each of the respective drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Turning now to FIGS. 1 and 2, there is shown an improved strain relief device 20 constructed in accordance with the concepts of the invention. Strain relief device 20 comprises a generally, tubular body member 22 having disposed about the outer surface thereof a plurality of generally equally spaced generally elongated protrusions 28 in longitudinal axial alignment with the longitudinal axis of body member 22. The inner surface of body member 22 is threaded as at 26 for threaded engagement with a threaded connector such as 38. Protrusions 28 provide convenient gripping means wherein body member 22 may be securely tightened about connector 38, thereby rigidly coupling strain relief device 20 to the connector 38. Although the inner surface of body member 22 of strain relief 20 is illustrated as threaded, other forms of regular or irregular circumferentially disposed protruding configurations may be provided for permitting body member 22 to interferingly engage appropriately matched configurations on the outer surface of a connector such as 38 wherein body member 22 may be rigidly secured thereto without departing from the spirit of the invention. Further, it should be understood that a series of flatted surfaces may be substituted for protrusions 28 of body member 22 to cooperatingly accept the jaws of a wrench or similar tool for securely tightening body member 22 about a connector such as 38, without again departing from the spirit of the invention. Integral with body member 22 and extending generally longitudinally from the second end 24 thereof are a pair of resilient coupling means such as generally elongated weblike members 30 terminating in a pair of generally arcuate clamping arms 32 each of which is integrally coupled to its associated resilient coupling means 30. The opposing generally concave inner surfaces of clamping arms 32 at least partially define a generally annular cable receiving orifice securable about the outer surface of an insulated electrical conductor or the like. Projecting outwardly from the outer surface of each clamping arm 32 is a raised portion 34 having a generally elongated transverse slot 36 therethrough, the raised portion 34 together with slot 36 thereby comprising a strap receiving means adapted to receive therein a strap such as 40 or similar tie for tightening clamping arms 32 about an insulated electrical conductor or a plurality of insulated electrical conductors such as 42, in a manner more clearly shown in FIG. 2.

Turning now to FIG. 3, there is shown a modification of a strain relief device 44 constructed in accordance with a further embodiment of the invention. A raised portion 48 projects outwardly from the outer surface of its associated clamping arm 46 defining a generally hooklike protrusion, the open end of which is directed to the left of FIG. 3, towards body member 52, providing a modified form of strap receiving means. A strap such as 40, as illustrated in FIG. 2, may be readily disposed about clamping arms 46 and at least partially tightened and positioned under the hooklike projections 48 and further tightened to rigidly secure clamping arms 46 about a plurality of conductors such as 42 of FIG. 2 in a manner as previously described with respect thereto. Body member 52 and resilient coupling means 53 duplicate essentially similar elements 22 and 30 of FIGS. 1 and 2.

Referring now to FIGS. 4 and 5, there is shown a further embodiment of a strain relief device 54 constructed in accordance with the concepts of the invention. Extending between the first end 48 and the second end 60 of body member 56 in aligned longitudinal axial relation thereto is a recess 62, providing a reduced cross-sectional area in the vicinity thereof to permit body member 56 to be readily parted along recess 62 for convenient disposition about the outer surface of a connector such as 76. A plurality of generally uniformly spaced apart discrete projections such as 64 are circumferentially disposed in two substantially parallel rows about the outer surface of body member 56 forming therebetween a guide which may be utilized to at least partially restrain therein a strap such as 74 disposed circumjacent body member 56 to rigidly secure the previously parted body member 56 about the outer surface of a connector such as 76. A pair of generally arcuate clamping arms 68 are integrally coupled to body member 56 by resilient coupling means 66 in a manner similar to that heretofore described with respect to FIGS. 1 and 2. Strap receiving means 72 and raised portions 70 shown in FIG. 4 duplicate substantially similar portions described above with reference to strain relief device 20 of FIGS. 1 and 2. A typical example of the manner in which a strain relief device such as 54 may be employed is shown in FIG. 5. Strap 74 is disposed about body member 56 and drawn up tightly to secure body member 56 to the outer surface of a connector such as 76. Projecting portions 64 circumferentially disposed about the outer surface of body member 56 provide guide means for strap 76, to insure the selective positioning and restraining thereof within the desired portion of body member 56. Strap 78 serves to maintain clamping arms 68 in tight intimate engagement with conductors 80 thereby insuring a minimum of relative movement therebetween.

Turning now to FIG. 6, there is shown a further embodiment of a strain relief device 82 constructed in accordance with the concepts of the invention. Strain relief device 82 is substantially similar to device 54 of FIGS. 4 and 5, differing, however, in the structural contour defining the pair of strap receiving means 86 projecting outwardly from an associated pair of clamping arms 84. As shown, each strap receiving means 86 comprises a hooklike projection, the open end 88 of which is directed towards the body member 90, similar to por tion 48 of FIG. 3, to at least partially engage and restrain a strap or similar item interposed therein.

Referring now to FIG. 7, there is shown a further embodiment of a body member 94 of a strain relief device 92 constructed in accordance with the concepts of the invention. A recess 96 is longitudinally disposed within the outer surface of body member 94 permitting body member 94 to be readily parted thereat. A plurality of inwardly directed generally arcuate portions such as 98, integral with the inner surface 102 of body member 94, are adapted to deformably engage matingly cooperable complementary portions of a connector or similar device about which strain relief device 92 is to be secured.

Turning now to FIGS. 8 and 9, there is shown a further embodiment of a unitary, integral strain relief device 104 constructed in accordance with the concepts of the invention. A pair of generally arcuate portions 112 define a body member 106 adapted to be detachably secured about the outer surface of a connector or similar item. An elongated web portion 110 extends between a pair of resilient coupling means 108 integrally joining said means, each of which is integrally coupled to and depends from its associated generally arcuate member 112. The arcuate body member portions 112 are thus radially deformable and the inner surfaces thereof define a variable connector receiving orifice wherein said body member 106 may be disposed circumjacent a connector such as 76 of FIG. 5 and secured thereabout about by strap means such as 74 of FIG. 5 tightened about the outer surface of body member 106 in a manner similar to that shown therein. The inner surface of each of the generally arcuate portions 112 of body member 106 may be threaded as at 114 for mating engagement with a complementarily contoured outer surface of a connector or similar article. It should be understood that although only two such portions 112 are shown, a plurality of generally arcuate body member segments may be provided, adjacently coupled one to another in generally annular fashion without departing from the spirit of the invention.

Turning now to FIGS. 10 and 11, there is shown a strain relief device 116 constructed in accordance with still another embodiment of the invention. The generally tubular body member 118 of strain relief device 116 is slit longitudinally of the axis thereof, as at 121. A web portion 122, in opposing diametrical relation to slit 121, and substantially narrower than the width of body member 118 serves as a convenient hinge means coupling together the separable, generally arcuate portions 120 of body member 118, whereby arcuate portions 120 may be readily deformed radially outwardly for convenient disposition about a range of selective connectors. The remaining structure of strain relief device 116, comprising a pair of clamping arms 124 integrally coupled to body member 118 by a pair of associated resilient coupling means 126 duplicate similar elements 68 and 66 of FIGS. 4 and 5.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

Iclaim:

1. A strain relief device comprising: a generally tubular body member having a first end and a second end; at least one generally arcuate clamping arm; and resilient coupling means extending outwardly from said second end of said body member generally longitudinally of the axis thereof, coupling said clamping arm to said body member; said clamping arm and said resilient coupling means, together with said body member, being formed of a unitary integral structure; said clamping arm having strap receiving means having an aperture therethrough disposed generally normal to the plane thereof and projecting generally outwardly therefrom, adapted to selectively engage and at least partially detachably confine therein a strap or similar item disposed about said clamping arm to detachably secure said arm to a cable or similar item adjacent thereto; the inner surface of said body member having a series of interruptions thereon for intimately engaging the outer surface of a connector or similar item.

2. A strain relief device comprising: a generally tubular body member having a first end and a second end; at least one generally arcuate clamping arm; and resilient coupling means extending outwardly from said second end of said body member generally longitudinally of the axis thereof, coupling said clamping arm to said body member; said clamping arm and said resilient coupling means, together with said body member, being formed of a unitary integral structure; said clamping arm having strap receiving means comprising a hooklike projection in generally aligned axial relation with the longitudinal axis of said body member, the open end of said hooklike projection being directed generally towards said body member and adapted to selectively engage and at least partially detachably confine therein a strap or similar item disposed about said clamping arm to detachably secure said arm to a cable or similar item adjacent thereto; the inner surface of said body member having a series of interruptions thereon for intimately engaging the outer surface of a connector or similar item.

3. A strain relief device comprising a generally tubular body member having a first end and second end; at least one generally arcuate clamping arm; and resilient coupling means extending outwardly from said second end of said body member generally longitudinally of the axis thereof, coupling said clamping arm to said body member; said clamping arm and said resilient coupling means, together with said body member, being formed of a unitary integral structure; said clamping arm having strap receiving means projecting generally outwardly therefrom, adapted to selectively engage and at least partially detachably confine therein a strap or similar item disposed about said clamping arm to detachably secure said arm to a cable or similar item adjacent thereto; the inner surface of said body member having a series of interruptions thereon for intimately engaging the outer surface of a connector or similar item; said body member further comprising a plurality of generally uniformly spaced apart circumferentially disposed discrete projections about the outer surface of said body member for receiving and at least partially positioning therebetween a strap or similar item.

4. A strain relief device as defined in claim 3 wherein said body member comprises a pair of hingedly coupled, integral, generally arcuate portions adapted to be secured about a selective range of said connectors.

5. A strain relief device as defined in claim 3 wherein said body member comprises a pair of generally arcuate portions maintained in variable spaced apart relation and integrally coupled together by web means coupled to and extending therebetween.

6. A strain relief device comprising: a generally tubular body member having a first end and a second end; a pair of generally arcuate clamping arms in opposing, generally diametrical, spaced-apart relation; and resilient coupling means extending outwardly from said second end of said body member generally longitudinally of the axis thereof, coupling said clamping arms to said body member; said clamping arms and said resilient coupling means, together with said body member, being formed of a unitary integral structure; each of said clamping arms having strap receiving means projecting generally outwardly therefrom; one of said strap receiving means having an aperture therethrough disposed generally normal to the plane thereof, and the other of said strap receiving means comprising a hooklike projection in generally aligned axial relation with the longitudinal axis of said body member; said strap receiving means being adapted to selectively engage and at least partially detachably confine therein a strap or similar item disposed about said clamping arm to detachably secure said arm to a cable or similar item adjacent thereto; the inner surface of said body member having a series of interruptions thereon for intimately engaging the outer surface of a connector or similar item.