A liquid-tight strain relief includes a tubular-shaped bushing and a dome-shaped gland. The bushing includes a flange with arcuate slots, a centrally-located aperture, a plurality of resilient outer fingers, and a shoe slideably received within a lateral groove of the bushing. The gland includes a head having a centrally-located membrane. The head is co-molded with and encapsulates the flange, resulting in a strain relief having a unitary construction. The strain relief is adapted to be inserted within an orifice of a work piece, and the outer fingers frictionally engage the work piece. A cable is inserted within the strain relief by puncturing the membrane, which then stretches and provides a seal against the cable. The cable is gripped to the strain relief when the shoe is pressed against the cable. The shoe is held against the cable by teeth on the shoe, which engage opposing locking ribs on the bushing.

FIELD OF THE INVENTION

The present invention relates to a strain relief and, more particularly, to a liquid-tight, co-molded strain relief for cables, wires, tubing, rods and other elongated objects.

BACKGROUND OF THE INVENTION

Liquid-tight strain reliefs are affixed in a liquid-tight manner in orifices of work pieces. The liquid-tight strain reliefs enable cables, wires, tubing or rods to be passed through them in a locked and liquid tight engagement, while providing strain relief protection. Liquid-tight strain reliefs are described in U.S. Pat. Nos. 5,405,172 and 8,398,419, which are incorporated herein by reference in their entirety. Liquid-tight strain reliefs are also described in pending U.S. patent application Ser. No. 14/459,495, filed Aug. 14, 2014 and published as U.S. patent publication No. 2015/0048614 on Feb. 19, 2015, which is incorporated herein by reference in its entirety.

SUMMARY OF THE INVENTION

A liquid-tight strain relief includes a tubular-shaped bushing and a dome-shaped gland co-molded with the bushing. The bushing includes a flange, a centrally-located aperture, a plurality of resilient outer fingers, and a plurality of resilient inner fingers extending from an inner wall and positioned within the aperture. The gland includes a head having a centrally-located membrane. The head of the gland is co-molded with and encapsulates the flange of the bushing, thereby resulting in a strain relief having a unitary construction. The strain relief is inserted within an orifice of a work piece, such as a panel, and the outer fingers frictionally engage the work piece. A cable is inserted within the strain relief by piercing the membrane, which stretches and provides a seal against the cable. The cable is inserted through the aperture of the bushing and the resilient inner fingers of the bushing flex outwardly to enable the cable to pass through, while engaging and digging into the cable to clasp it and provide strain relief. In an alternate embodiment the inner fingers are replaced by a laterally moveable shoe which is manually pressed against the cable to clasp it. The cable-gripping shoe is slideably received within a lateral recess of the bushing. The gland includes a head having an outer surface, an inner surface, an annular interior portion located within said inner surface and encapsulating said annular flange of the bushing, and a central area of reduced thickness to facilitate the puncturing of the gland by the cable upon insertion.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring toFIGS. 1 through 7, in an embodiment, a liquid-tight strain relief10includes a tubular-shaped bushing12and a dome-shaped gland14attached to the bushing12. In an embodiment, the gland14is co-molded with the bushing12in a manner that will be described hereinafter. In an embodiment, the bushing12is made from a thermoplastic material, while the gland14is made from a thermoplastic elastomer (TPE). In other embodiments, the bushing12and the gland14may be made from other suitable materials known in the art.

With continued reference toFIGS. 1 through 7, in an embodiment, the bushing12includes a cylindrical-shaped housing16having a first end18and second end20opposite the first end18, a peripheral flange22extending outwardly from the first end18, and a centrally-located aperture24that extends from the first end18to the second end20. The housing16of the bushing12further includes an inner wall26, an outer wall28, and a pair of diametrically opposed cutouts30extending from the inner wall26to the outer wall28(one of which is shown inFIG. 6). Each of the cutouts30includes a pair of spaced-apart and parallel, longitudinally extending slots32a,32b. Each of the slots32a,32bincludes a first end34and second end36opposite the first end34. The first ends34of each of the slots32a,32bare connected by a corresponding transverse slot38. Each pair of the slots32a,32band the corresponding transverse slot38define and surround a resilient outer finger40. The outer finger40includes a first end39attached integrally to the housing16, and an opposite free end41. In an embodiment, the bushing12includes two of the outer fingers40that are diametrically opposed to one another. In other embodiments, the bushing12includes more or less than two of the outer fingers40. Each of the outer fingers40includes an outer surface42having a plurality of elongated ribs43for frictional engagement with a work piece, which will be described hereinafter. In other embodiments, the outer surface42of the each of the outer fingers40may include other frictionally-engaging features known in the art.

Referring toFIGS. 5 and 7, in an embodiment, the bushing12includes a plurality of resilient inner fingers44. Each of the inner fingers44includes a first end46, which is attached to the inner wall26of the bushing12proximate to the first end18thereof, and a second, free end48opposite the first end46, which is positioned within the aperture24of the bushing12. In an embodiment, the first end46of each of the inner fingers44is integral with the inner wall26. In an embodiment, each of the inner fingers44extends obliquely from the inner wall26of the bushing12within the aperture24. In an embodiment, the second end48of each of the inner fingers44includes a pointed tip50. It will be apparent to those of skill in the art that the plurality of resilient inner fingers44may include varying quantities of inner fingers44. In an embodiment illustrated inFIG. 7, the bushing12includes two of the inner fingers44that are diametrically opposed to one another. In another embodiment, the bushing12includes three of the inner fingers44. In another embodiment, the bushing12includes four of the inner fingers44. In an embodiment illustrated inFIGS. 3, 13 and 14, the bushing12includes two of the inner fingers44that are diametrically opposed to one another and two of the outer fingers40that are diametrically opposed to one another, and a diameter defining the diametric opposition of the two inner fingers44is offset by a right angle from a diameter defining the diametric opposition of the two outer fingers40.

Referring back toFIGS. 1 through 7, in an embodiment, the gland14includes a domed-shaped head52having a convex outer surface54and a concave inner surface56, which meet to form an annular lip58. A centrally-located, substantially circular-shaped depression60is formed within the outer surface54of the head52, which culminates at a centrally-located membrane62. In an embodiment, the membrane62includes a thickness that is sufficient for the membrane to be pierced, which will be described hereinafter. In an embodiment, the gland14is co-molded with the bushing12such that the flange22of the bushing12is encapsulated within an annular interior portion64of the head52of the gland14. When the gland14is co-molded to the bushing12, the membrane62resides within the aperture24of the bushing12proximate to the first end18of the bushing12.

It will be known to those of skill in the art that when items are described as being “co-molded” to one another, reference is made to a fabrication process whereby items made of different materials are fabricated simultaneously within a single mold. For example, when the bushing12and the gland14of the exemplary liquid-tight strain relief10are described herein as being co-molded to one another, those of skill in the art will understand this description to mean that the bushing12and the gland14are made of different materials that are formed within the same mold at the same time. As discussed above, these materials may include a thermoplastic forming the bushing12and a thermoplastic elastomer (TPE) forming the gland14.

In use, the liquid-tight strain relief10is sized and shaped to be affixed in a liquid-tight manner within an orifice of a work piece, such as a panel or other structure (not shown in the Figures). When the strain relief10is installed within the orifice in the work piece, the ribs43on the outer fingers40frictionally engage the work piece to facilitate the fixation of the strain relief10therein. In an embodiment, as the strain relief10is inserted into the orifice of the work piece, the ribs43are compressed to fit within the orifice. Once the strain relief10is secured within the orifice of the work piece, the annular lip58of the gland14, which acts on the engaged surface of the work piece, forms a liquid-tight seal thereon.

Referring toFIGS. 8 through 14, when a cable C (or a wire, tubing, rod and other elongated object) is inserted in the strain relief10, it pierces the membrane62of the gland14(seeFIGS. 8, 12 and 14). In this regard, the membrane62stretches and forms a liquid-tight seal around the cable C. In another embodiment, the cable C may first be installed through the strain relief10, after which the strain relief10may be engaged in position along the cable C and then affixed within the orifice of the work piece. When the cable C is further inserted through the aperture24of the bushing12, the cable C engages the inner fingers44which flex to allow the cable C to be inserted there through. As a result of the resiliency of the inner fingers44, they are movable outwardly towards the inner wall26of the bushing12from a first, disengaged position to a second, engaged position, in which the pointed tips50of the inner fingers44dig-in and clasp the outer surface of the cable C to provide strain relief (seeFIGS. 12 and 14).

Another preferred embodiment of the invention is shown inFIGS. 15 through 17. In this embodiment, the inner fingers are replaced by a manually operated shoe72, which grips the cable “C” or other inserted object. Referring toFIG. 15, a shoe72is slideably received within a lateral recess74of the bushing70, which has sidewalls and top and bottom surfaces that closely match the shoe dimensions. The shoe72has a series of teeth63on the exterior of its opposite sides. The flange78has a plurality of arcuate slots77that extend completely through the flange from a top side to the bottom side of the flange68. The gland75has a central area of reduced thickness76to facilitate puncturing by an object such as a cable. Referring toFIG. 16, the gland75is co-molded with the bushing and during that process material of the gland encapsulates the flange78while passing through the slots77in the flange. Rotation of the gland75about the flange78is prevented by the gland material within the slots.

Engagement between the bushing60and the shoe72is depicted inFIG. 17. The teeth73on the shoe72engage the two diametrically-opposed locking ribs71projecting inwardly from the sides of the inner wall of the bushing70. When the show72is manually pressed against a cable or other object (not shown) extending through the bushing, the cable becomes clamped between the shoe72and an arcuate portion of the bushing inner wall79opposite the shoe72. The ratchet action of the teeth73against the ribs71secures the cable against the counteracting resilience of the cable and bushing components. The series of teeth73on the shoe72provides the adaptability of supplying a strong clamp force to cables or other objects of different diameters.

It should be understood that the embodiments described herein are merely exemplary and that a person skilled in the art may make many variations and modifications without departing from the spirit and scope of the invention. Accordingly, all such variations and modifications are intended to be included within the scope of the embodiments described herein as defined in the appended claims.