SEALING UNIT, PARTICULARLY FOR ELECTRIC CONNECTORS

Abstract: A sealing unit (1) about an elongated element (4), particularly a cable of an electric connector, and presenting a first (2) and second (3) elastically deformable sealing element facing each other, in use, on either side of the elongated element (4), and each presenting complementary first (7) and second (8) portions; the sealing elements (2, 3) being pressed against each other so that the first and second portions (7, 8) cooperate in sealing manner with each other; and at least one (7) of the first and second portions (7, 8) being deformed by the other portion (8) to cooperate in sealing manner with the elongated element (4).

Description: SEALING UNIT, PARTICULARLY FOR ELECTRIC CONNECTORS TECHNICAL FIELD The present invention relates to a sealing unit about one or more elongated elements such as cables, pipes and similar, and is particularly, though not exclusively, suitable for insertion between the casing and one or more cables of an electric connector, to which application the following description refers purely by way of example. BACKGROUND ART The electric cable of sealed electric connectors is normally sealed by means of a sealing element presenting a through opening through which the cable is fitted. The sealing element may be a straightforward rubber ring for a single cable, as described for example in US-A-5069639, or a multiple seal with a number of holes for respective cables, as described for example in US-A-4460227. As the efficiency of the sealing element depends on it exerting a certain amount of pressure on the cable, the section of the opening must be smaller than the cross section of the cable to produce a certain amount of radial forcing when the cable is assembled. Known sealing elements of the above type present several drawbacks. One way of assembling the connector is to insert the cable through the sealing element before crimping the terminal on to the cable, which solution, however, involves a fairly complex, time-consuming assembly sequence. Alternatively, the sealing element may be assembled beforehand inside the casing, in which case the electric terminal, already crimped to the cable, must be fitted through the opening in the seal when the terminal is inserted inside the casing. On account of the small section of the opening in the seal, such a solution may result in severe distortion of the seal, and in tearing or cutting of the edge of the opening, thus impairing sealing efficiency in actual use. What is more, subsequent removal and reassembly may result in further damage, to the extent that the seal must eventually be replaced, with all the disadvantages this entails in terms of time and money. DISCLOSURE OF INVENTION It is an object of the present invention to provide a sealing unit, particularly for an electric connector, designed to overcome the drawbacks typically associated with known seals of the aforementioned type. According to the present invention, there is provided a sealing unit about an elongated element; characterized in that it comprises a first and second elastically deformable sealing element facing each other and which are gripped against each other and against said elongated element interposed between the sealing elements; said sealing elements comprising respectively at least a first . and at least a second portion complementary in shape; and at least one of said portions being deformable by the other of said portions to cooperate in sealing manner with said elongated element. BRIEF DESCRIPTION OF DRAWINGS Two preferred, non-limiting embodiments of the present invention will be described by way of example with reference to the accompanying drawings, in which: Figures 1 and 2 show schematic partial views in perspective of a sealing unit in accordance with the teachings of the present invention and in two different operating positions; Figure 3 shows a partially sectioned longitudinal view of an electric connector featuring a pair of sealing units according to the present invention; Figure 4 shows a cross section of the Figure 3 connector, comprising a portion a) along line IVa-IVa, and a portion b) along line IVb-IVb in Figure 3. BEST MODE FOR CARRYING OUT THE INVENTION Number l in Figures 1 and 2 indicates a sealing unit comprising a pair of sealing elements 2, 3, which are placed together and pressed against each other to cooperate in sealing manner with a number of parallel electric cables 4 (only one shown in Figure 1) interposed between elements 2 and 3. Elements 2 and 3 are molded from elastomeric material, and comprise respective shaped surfaces 5, 6 facing and cooperating with each other. Each of surfaces 5, 6 presents a number of first portions 7 and second portions 8 defining bands of surfaces 5, 6 extending transversely in relation to cables 4 and alternating in a direction parallel to cables 4. Portions 7, 8 of element 2 are offset axially in relation to portions 7, 8 of element 3, so that a portion 7 of one element mates with a portion 8 of the other. Portions 7 and portions 8 are complementary in shape. More specifically, first portions 7 comprise a number of pairs 9 of sealing lips 10; the lips 10 in each pair 9 define a C-section seat 11 of a depth greater than the diameter of cables 4, and housing a portion of a respective cable; and the adjacent lips 10 of two adjacent pairs 9 are separated by a C-section gap 12 shallower than seats 11. Second portions 8, on the other hand, present an undulated contour defined by a number of crests 13 located at gaps 12 of adjacent first portions 7, and alternating with a number of grooves 14 located at seats 11 of adjacent first portions 7. Second portions 8 are sunk in relation to first portions 7 so as to form a shoulder 15 between the bottom of seat 11 and the bottom of adjacent groove 14. Lips 10 present a substantially trapezoidal axial section; and the lips 10 of adjacent portions 7 define respective gaps 16 also presenting a substantially trapezoidal section but slightly less than the section of lips 10 when undeformed. Sealing elements 2, 3 present respective flat supporting faces 17 opposite surfaces 5, 6 and which cooperate in sealing manner with respective pairs of gripping elements (not shown) between which unit 1 is compressed in use. Unit 1 operates as follows. In Figure 1, sealing elements 2, 3 are shown in the open position facing each other to permit insertion of cables 4 (only one shown) between respective surfaces 5, 6. Cables 4 are inserted so as to engage seats 11 in portions 7 of each element 2, 3 when elements 2, 3 are placed together and pressed against each other (Figure 2) to mate surfaces 5 and 6. Pairs 9 of lips 10 of portions 7 of one element 2 or 3, which almost entirely surround a respective portion of cable 4, fit inside the corresponding grooves 14 of respective portions 8 of the other element 3 or 2; and, at the same time, crests 13 of each portion 8 engage in forced manner the gaps 12 between pairs 9 of lips 10, so that lips 10 in each pair 9 are deformed about respective cable 4 and cooperate end to end. Lips 10 thus provide for sealing the entire periphery of the cable, with the exception of the portion at which they cooperate end to end; which portion, however, is located at shoulder 15 defined by the adjacent portion 7 and which provides for preventing any infiltration. The alternating arrangement of portions 7 and 8 therefore defines a labyrinth seal for ensuring absolutely airtight sealing of cables 4; which performance is further improved by the axial force produced by the trapezoidal section of lips 10 and dimensional interference with respective gaps 16. Figures 3 and 4 show an electric connector 19 featuring a pair of sealing units 20 in accordance with the teachings of the present invention. Connector 19 comprises an insulating casing 21 in turn comprising a main body 22 with two rows of cavities (not shown) housing respective electric terminals 23; and two shells 24 snapped together on either side of an intermediate wall 25 of body 22 separating the two rows of cavities and projecting from body 22 so as to separate the two rows of cables 4 of respective terminals 23. Each shell 24 defines with wall 25 a chamber 29 housing a respective sealing unit 20. Each unit 20 comprises a sealing element 2 and a sealing element 3 with respective surfaces 5, 6 as described with reference to unit 1 in Figures 1 and 2; and elements 2, 3 are compressed against each other between respective shell 24 and wall 25, and cooperate in sealing manner with opposite sides of cables 4. Shells 24 are secured to each other by means of elastic snap-on fasteners, and are retained on wall 25 in the direction parallel to cables 4 by retaining means not shown. To ensure stable transverse positioning of elements 2, 3 and enhance the sealing effect due to interaction of portions 7 and 8, wall 25 and shells 24 are conveniently undulated and defined by a number of equally spaced projections 27 cooperating with respective recesses 28 formed in surfaces 17 of sealing elements 2, 3 at crests 13 of portions 8 and gaps 12 of portions 7. The advantages of units 1 and 20 according to the present invention are as follows. By virtue of the sealing unit being formed in two separate parts between which the cables are inserted, it may be assembled and disassembled with the terminals already crimped to the respective cables, with no need to force the terminals through small-section openings as with known one-piece seals. Moreover, when gripped together against the cable, the complementary shape of the two sealing elements causes them to flex into sealing contact with the cable. And finally, the axially alternating arrangement of portions 7 and 8 defines a labyrinth seal ensuring substantially airtight sealing of the unit. Clearly, changes may be made to units 1 and 20 as described and illustrated herein without, however, departing from the scope of the present invention. For example, changes may be made to the number of portions 7, 8; to the number of cables 4 for sealing; or to the shape of lips 10 and respective seats 11.

Claims: CLAIMS 1) A sealing unit (1; 20) about an elongated element (4) ; characterized in that it comprises a first (2) and second (3) elastically deformable sealing element facing each other and which are gripped against each other and against said elongated element (4) interposed between the sealing elements (2, 3); said sealing elements (2, 3) comprising respectively at least a first (7) and at least a second (8) portion complementary in shape; and at least one (7) of said portions being deformable by the other (8) of said portions (7, 8) to cooperate in sealing manner with said elongated element (4) . 2) A unit as claimed in Claim 1, characterized in that said first portion (7) comprises at least one pair (9) of sealing lips (10) defining a seat (11) for said elongated element (4) ; and said second portion (8) comprises at least one groove (14) for receiving said sealing lips (10) and deforming them against said elongated element (4) . 3) A unit as claimed in Claim 1 or 2, characterized in that said first portion (7) comprises a number of said pairs (9) of lips (10) cooperating with respective said elongated elements (4) and separated by respective gaps (12) ; said second portion (8) presenting an undulated contour defined by a number of said grooves (14) alternating with a number of crests (13) cooperating in forced manner with said gaps (12) of said first portion (7) . 4) A unit as claimed in Claim 3, characterized in that each of said sealing elements presents a number of said first and second portions (7, 8) alternating in a direction parallel to said elongated elements (4) . 5) A unit as claimed in Claim 4, characterized in that said second portions (8) of each said sealing element present a sunken profile in relation to said first portions (7) ; a shoulder (15) being formed between the bottom of said seats (11) in each said first portion (7) and the bottom of said grooves (14) in the adjacent said second portion (8) . 6) A unit as claimed in Claim 4 or 5, characterized in that said lips (10) of said first portions (7) of each said sealing element (2, 3) are so shaped as to engage in forced manner a gap (16) defined between the lips (10) of a pair of said first portions (7) of the other said sealing element (3, 2). 7) A sealing unit (1; 20) for an electric connector (19) and which is interposed between the casing (21) and at least one cable (4) of the connector; characterized in that it comprises a first (2) and second (3) elastically deformable sealing element facing each other on either side of said cable (4) , and which are pressed against each other and against the cable (4); said sealing elements (2, 3) comprising respectively at least a first (7) and at least a second (8) portion complementary in shape; and at least one (7) of said portions being deformable by the other (8) of said portions (7, 8) to cooperate in sealing manner with said cable (4) . 8) An electric connector (19) comprising an insulating casing (21) ; at least one electric terminal (23) housed in said casing and presenting a respective cable (4) ; and sealing means (20) interposed between said cable (4) and said casing (21) ; characterized in that said sealing means comprise at least one sealing unit (20) as claimed in any one of the foregoing Claims. 9) A connector as claimed in Claim 8, characterized in that said sealing unit (20) is compressed between a fixed portion (25) and a movable element (24) of said casing (21) . 10) A connector as claimed in Claim 9, characterized in that said sealing elements (2, 3) of said sealing unit (20) comprise respective shaped supporting surfaces (17) presenting recesses (28) at said gaps (12) and said crests (13) of said first and second portions (7, 8); said fixed portion (25) and said movable element (24) of said casing (21) presenting respective numbers of projections (27) cooperating with said recesses (28) .

Inventors: BIGOTTO PIER CARLO, GENTA ALESSANDRO, BIGOTTO, PIER, CARLO, GENTA, ALESSANDRO
Applicants: BIGOTTO PIER CARLO, FRAMATOME CONNECTORS INT, GENTA ALESSANDRO, BIGOTTO, PIER, CARLO, FRAMATOME CONNECTORS INTERNATIONAL S.A., GENTA, ALESSANDRO
Application year: 1995
Main classification: H01R13
IPC codes: H01R13