Expandable seal arrangement

Abstract: An arrangement for radially expanding a tubular gasket (16) includes a sliding sleeve (24) and a compression sleeve (20). The sliding sleeve is formed of a thin membrane of relatively rigid material, such as nylon, hypalon or polyester. The sliding sleeve (24) is positioned adjacent an inner surface of that portion of the tubular gasket to be expanded. The compression sleeve is disposed immediately adjacent the sliding sleeve such that the sliding sleeve serves as a slip plate for the compression sleeve when the sleeves are expanded against the inner surface of the tubular gasket. The sliding sleeve may be attached to or integrally molded into the inner surface of the tubular gasket (16). Another aspect of the invention involves forming the compression sleeve so as to allow it to be locked in any one of a plurality of expanded positions. The locking mechanism may be integrally formed with the compression sleeve, or may be formed as a separate element which may be molded into, or otherwise pre-attached to, the inner surface of the tubular gasket.

Description: The present invention relates to a radially expandable seal arrangement and, more specifically, to an arrangement for radially expanding a tubular gasket into compressive sealing engagement with the wall of an opening. The arrangement described below is an improvement upon the invention described in my previously issued U.S. Patent 4,478,437. To the extent necessary for a full and complete understanding of the present invention, the disclosure of U.S. Patent 4,478,437 is incorporated herein by this reference thereto. In U.S. Patent 4,478,437, an arrangement for sealing a tubular gasket against the wall of an opening in a manhole riser is described. That arrangement includes a radially expandable split sleeve (28) coaxially received within the gasket adjacent the portion of the gasket which is to be expanded. The sleeve, which is shown in additional detail in Figures 3-11 of that patent, is expanded (along with the gasket) by use of a scissors-shaped tool (70) which is operated by a hydraulic cylinder (78) operatively connected between the scissor arms of the tool. Two pins are provided on the distal ends of the arms. These pins are inserted into two openings in opposing ends of the split sleeve, and hydraulic pressure is used to expand the sleeve and gasket until the sleeve ends lock in the expanded position. The arrangement described in U.S. Patent 4,478,437 works well for its intended purpose. However, a relatively strong force must be exerted by the hydraulic tool in order to expand the compression sleeve and gasket into the final locked position. An object of the present invention is to provide an improved arrangement wherein the magnitude of the force required to expand the sleeve into its final locked position is reduced. This allows a corresponding reduction in the size and weight of the tooling used for installation of the gasket, and for greater equalisation of the compression forces applied to the gasket. A preferred feature of the present invention is to provide an alternative arrangement for locking a split sleeve in the expanded position. This alternative arrangement provides a range of locking positions which enable a single sleeve to be used for openings having a relatively wide range of diameters. The resulting "standardisation" in sleeve length and structure allows for substantial reductions in sleeve production costs. The invention as defined in claim 1 provides an arrangement for radially expanding a tubular gasket which comprises a sliding sleeve, a compression sleeve, means for expanding the sliding sleeve, compression sleeve and tubular gasket from a relaxed position into an expanded position, and means for locking the compression sleeve in the expanded position. In the preferred constructions as later illustrated, the sliding sleeve is formed of a thin membrane of relatively rigid material, such as nylon, hypalon or polyester. The sleeve is positioned adjacent an inner surface of that portion of the tubular gasket to be expanded. The compression sleeve formed of a relatively stiff, but resiliently flexible material is disposed immediately adjacent the sliding sleeve such that the sliding sleeve serves as a slip plate for the compression sleeve when the sleeves are expanded against the inner surface of the tubular gasket. In one embodiment, the sliding sleeve is formed in a U-channel shape, and is dimensioned so as to accept the compression sleeve within the upstanding sidewalls of the U-shaped cross-section. The thickness of the upstanding sidewalls is substantially greater than the wall thickness of the remaining portion of the sliding sleeve. The thin portion of the sliding sleeve is designed to stretch or break when the compression sleeve, sliding sleeve and gasket are expanded. If necessary, the sliding sleeve may be segmented into portions (such as by perforations) which break apart when the sliding sleeve is expanded. The sliding sleeve may be adapted to fit within a groove formed in the inner surface of the tubular gasket, alternatively, the sliding sleeve may be attached to or molded into the inner surface of the tubular gasket. The sliding sleeve may be attached to the outer surface of the compression sleeve. The sliding sleeve of the present invention may be used with a compression sleeve such as that shown in U.S. Patent 4,478,437. Alternatively, a compression sleeve which locks in a plurality of expanded positions may be used. One embodiment of such a compression sleeve includes a plurality of inwardly projecting teeth on a first end of the sleeve, and at least one tooth engaging surface on a second opposing end of the sleeve which may engage any one of the plurality of inwardly projecting teeth to lock the sleeve in a corresponding plurality of expanded positions. The second end of the sleeve is formed to include a recess to receive one or more of the plurality of teeth so as to maintain a relatively smooth and continuous profile around the outer circumference of the sleeve. In another embodiment, the compression sleeve comprises a C-shaped structure and a separate, arc-shaped locking mechanism which engages the ends of the C-shaped sleeve so as to lock the sleeve in an expanded position, and so as to form a relatively smooth and continuous profile around the outer circumference of the compression sleeve/locking mechanism assembly. In this arrangement, teeth-like structures may be provided on opposing ends of the C-shaped sleeve. Mating teeth-like structures are similarly provided on the arc-shaped element to engage the teeth-like structures on the opposing ends of the sleeve to secure the sleeve into an expanded and locked position. The arc-shaped element may be molded into the gasket (or otherwise pre-attached to the inner surface of the gasket) for ease of use and installation. In either embodiment of the sleeve, a pair of tabs may be provided to engage an appropriate tool for expanding the sleeve and gasket into position. The tabs may be designed to fail when a predetermined amount of force is applied thereto in order to limit the magnitude of the force which may be applied to the sleeve/gasket assembly. Advantages of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective, partially cut-away and sectioned view of a seal installation constructed in accordance with the principles of the present invention. Figure 2 is a front view of the sliding sleeve of the present invention. Figure 3 is a cross-sectional view taken along line 3-3 of Figure 2. Figure 4 is a side view of the sliding sleeve of Figure 2. Figure 5 is a front view, partially cut away, of a compression sleeve suitable for use with the present invention. Figure 6 is a front view of an alternative embodiment of the compression sleeve shown in Figure 5. Figure 7 is a sectional view of an arrangement which utilizes yet another alternative embodiment of the compression sleeve. DETAILED DESCRIPTION OF THE DRAWINGS Referring to the drawings, Figure 1 shows a reinforced concrete manhole riser or monolithic base, generally indicated by reference numeral 10, which is provided with a pipe-receiving opening 12 in a sidewall thereof. A pipe 14 is received within opening 12 and extends to a position beyond inner surface 15 of manhole riser or base 10. To seal pipe 14 within hole 12, a gasket apparatus is employed which includes an elongate sleeve 16 of resilient, elastomeric material, such as rubber, neoprene or a suitable plastic. A conventional screw-type, annular clamping band (or bands) 18 is provided on one end of gasket 16 to clamp the gasket against the outer surface of pipe 14. At the opposing end of the gasket, a radially expandable, split sleeve 20 is coaxially received within gasket 16, and is expandable between a first relaxed position into a second expanded position. When sleeve 20 is expanded to its second expanded position, portion 22 of gasket 16, which lies radially adjacent sleeve 20, is sealingly compressed against the wall of opening 12, as previously described in U.S. Patent 4,478,437. An additional component in the arrangement shown in Figure 1 which is not found in the arrangement disclosed in U.S. Patent 4,478,437 is sliding sleeve 24. Sleeve 24 is an annular structure disposed adjacent an inner surface of portion 22 of gasket 16, and immediately adjacent the outer circumferential surface of compression sleeve 20. Sleeve 24 is expandable with compression sleeve 20 from a first relaxed position into a second expanded position, as described in more detail below. Sliding sleeve 24 is formed of a thin membrane of relatively rigid material, such as nylon, hypalon, or polyester. By virtue of its position and composition, sleeve 24 serves as a slip plate for compression sleeve 20 when the sleeves and gasket are expanded into the second expanded position. This arrangement significantly lowers the magnitude of the force required to expand compression sleeve 20 due to the fact that the coefficients of friction between compression sleeve 20 and sliding sleeve 24 and gasket 16 and sliding sleeve 24 are substantially lower than the coefficient of friction between compression sleeve 20 and gasket 16. This also allows greater equalization of compression of the material in gasket 16, thus effecting a more positive seal between portion 22 and opening 12. Figure 2 shows a front view of sliding sleeve 24. Sleeve 24 is generally circular in shape and extends a full 360° around its circumference. In an alternative embodiment, portion 26, which is approximately located between the break lines 28, may be omitted in the area of the locking mechanism on compression sleeve 20, as is shown in Figure 1. Figure 3 shows a cross-section of sliding sleeve 24 taken along line 3-3 of Figure 2. This embodiment of sleeve 24 is a U-shaped channel having relatively thick upstanding sidewalls 30 and 32, and a relatively thin connecting wall 34. The width of connecting wall 34 ( i.e. , the space between sidewalls 30 and 32) is dimensioned so as to receive compression sleeve 20 within sidewalls 30 and 32. Additionally, the thickness of upstanding sidewalls 30 and 32 is substantially greater than the wall thickness of connecting portion 34. Figure 4 shows a side-view of sliding sleeve 24. As illustrated at multiple locations 36, connecting wall 34 of sleeve 24 may be perforated or otherwise weakened to allow sleeve 24 to stretch, break, or otherwise expand as the compression sleeve is moved from a relaxed position into an expanded and locked position. Sliding sleeve 24 may be hand-positioned within gasket 16 or, alternatively, may be molded or otherwise adhered into position during an appropriate point in the gasket manufacturing process. Adhesives 37 could be applied as shown, for example, in Figure 4. Sleeve 24 may also be pre-fitted onto compression sleeve 20. However, since sleeve 24 serves as a slip plate for compression sleeve 20, the use of adhesives or other materials between sleeve 20 and sleeve 24 is generally not preferred. Gasket 16 is installed in the same general manner as is described in U.S. Patent 4,478,437, except for the additional step of providing sliding sleeve 24 between compression sleeve 20 and gasket 16. As noted, provision of sleeve 24 substantially decreases the magnitude of the force required to expand compression sleeve 20 into the locked position. Figure 5 shows a front view of an alternative form of compression sleeve 40 suitable for use in a seal arrangement constructed in accordance with the present invention. Compression sleeve 40 is formed of a resiliently flexible material, such as metal or plastic. The embodiment of compression sleeve 40 illustrated in Figure 5 comprises a first C-shaped portion 42 and a separate locking mechanism 44. Respective end portions 46 and 48 of portion 42 are formed to provide recesses 50 and 52 for reasons which will be discussed below. At the distal end of each recess are generally outwardly extending raised surfaces 54 and 56, respectively. Surfaces 54 and 56 engage respective ones of a plurality of inwardly projecting teeth formed on the underside of locking portion 44 to lock compression sleeve 40 in one of a plurality of expanded positions. The arrangement illustrated in Figure 5 shows compression sleeve 40 expanded and locked in its maximally diametrical expanded position. Sleeve 40 may be readjusted to any one of several positions by positioning surfaces 54/56 adjacent different ones of the plurality of teeth 58/60, respectively. When positioned for a smaller diametrical position. The outermost teeth ( i.e. , the teeth which are distal from the tooth which engages surface 54 or 56) are received within recesses 50 or 52, as shown by dashed lines. This arrangement allows for maintaining a relatively smooth and continuous profile around the entire outer circumference of compression sleeve 40. An advantage to the structure depicted in Figure 5 is that locking portion 44 may be molded into, or otherwise adhered ( e.g. , by glue), to the interior surface of gasket 16 prior to the time of installation of the gasket in the opening. In such an arrangement, sliding sleeve 24 would extend around portion 42 of compression sleeve 40, and would preferably not extend into the arc-shaped area occupied by locking portion 44. As previously mentioned, sliding sleeve 24 may also be molded into gasket 16 (along with locking portion 44 to simplify assembly and installation of the seal arrangement. An alternative embodiment of the locking ring of Figure 5 is shown in Figure 6. Compression sleeve 62 is similar to sleeve 40, except that sleeve 62 is formed of a continuous strip of resiliently flexible material. A plurality of inwardly projecting teeth 64 are formed on a first end 66 of sleeve 62, while a tooth receiving recess 68 is formed on an opposing end 70 of ring 62. Surface 72 engages one of the teeth 64 to lock sleeve 62 into an expanded position. Figure 7 shows yet another embodiment of a compression sleeve 74 which comprises a C-shaped portion 76 and a separate locking portion 78. Ends 80 of sleeve 76 are similarly formed and include a plurality of serrations or outwardly projecting teeth 82, and a pair of tabs 84, as illustrated. Locking portion 78 is an arc shaped member which is provided with inwardly projecting serrations or teeth 86 on opposing ends thereof. Teeth 86 are intended to engage or mate with teeth 82 to lock sleeve 74 in an expanded position. As with the embodiment of Figure 55, locking portion 78 may be molded or glued to elastomeric gasket 16 as is illustrated in Figure 7. Portion 76 is then positioned so as to allow teeth 82 and 86 to engage. Compression sleeve 74 may, thus, be adjustably expanded into a plurality of positions and secured in those positions by the engaging teeth. Also illustrated in Figure 7 is a hinged tool 88 which may be used to apply an expanding force to portion 76 of sleeve 74. Tool 88 is hinged at 90, and includes a pair of arms 92 and 94 which engage tabs 84 on ends 80 of sleeve 74. A force F applied to the hinge 90 by, for example, a hydraulic jack will cause portion 76 to expand. As this expansion occurs, corresponding sets of teeth engage to maintain portion 76 in the expanded condition. If desired, tabs 84 may be designed to fail when a predetermined force F is applied to tool 88 so that the proper compression force may be more easily achieved in each installation. Sliding sleeve 24 may, of course, also be used in this arrangement, as illustrated.

Claims: An arrangement for radially expanding a tubular gasket (16) into compressive sealing engagement with the wall of an opening, comprising: a sliding sleeve (24) and a compression sleeve (20), said sliding sleeve (24) being formed of a material which has a lower coefficient of sliding friction when in contact with the compression sleeve (20) than does the tubular gasket (16), said sliding sleeve (24) being adapted for positioning adjacent an inner surface of that portion (22) of the tubular gasket (16) to be expanded, said sliding sleeve (24) being expandable from a first relaxed position into a second expanded position, and said sliding sleeve (24) being formed so as to be plastically deformable as it is expanded into the second expanded position; said compression sleeve (20) being formed of a relatively stiff but resiliently flexible material capable of transmitting an outwardly directed force to the inner surface of the tubular gasket (16) and being expandable from a first relaxed position into a second expanded position, said compression sleeve (20) being adapted for disposition immediately adjacent said sliding sleeve (24) such that said sliding sleeve (24) serves as a slip plate for the compression sleeve (20) when the sleeves are expanded into the second expanded position; means (84) for expanding the tubular gasket (16), the sliding sleeve (24), and the compression sleeve (20) from the first relaxed position into the second expanded position such that an outer surface of the tubular gasket (16) engages the wall of the opening, said sliding sleeve (24) being plastically deformable as to create and maintain a low friction slip plane between the compression sleeve (20) and the inner surface of the tubular gasket (16) as the gasket (16) is expanded into sealing engagement with the wall of the opening; and means (54-60) for locking the compression sleeve (20) in the second expanded position. An arrangement according to claim 1, wherein said sliding sleeve (24) is formed in a U-channel shape, and wherein said compression sleeve (20) is dimensioned so as to fit within the upstanding sidewalls (30,32) of the U-shaped sliding sleeve (24). An arrangement according to claim 2, wherein the thickness of the upstanding sidewalls (30,32) of the U-shaped sliding sleeve (24) is substantially greater than the wall thickness of the remaining portion (34) of the sliding sleeve. An arrangement according to any preceding claim, wherein said sliding sleeve is moulded into the inner surface of the tubular gasket (16). An arrangement according to any preceding claim, wherein said sliding sleeve (24) is attached to an outer surface of the compression sleeve (20). An arrangement according to any preceding claim, wherein said sliding sleeve (24) is segmented into portions which break apart when the sliding sleeve (24) is expanded into the second expanded position. An arrangement according to any one of claims 1 to 5, wherein said sliding sleeve (24) is formed (at 36) so as to allow selected portions of the sleeve (24) to stretch when the sliding sleeve (24) is expanded into the second expanded position. An arrangement according to any preceding claim, wherein said means for locking the compression sleeve in the second expanded position comprise a plurality of inwardly projecting teeth (64) on a first end (66) of the compression sleeve (62), and at least one tooth engaging surface (72) on a second opposing end (70) of the compression sleeve (62), whereby said compression sleeve (62) can be expanded and locked in a plurality of expanded positions. An arrangement according to claim 8, wherein said second end (70) of the compression sleeve (62) is formed to include a recess (68) to receive one or more of said plurality of teeth (64) so as to maintain a relatively smooth and continuous profile around the outer circumference of the compression sleeve (20). An arrangement according to any one of claims 1 to 7, wherein said means for locking the compression sleeve (20) is moulded into, or otherwise attached to, the inner surface of the gasket (16). An arrangement according to claim 1, wherein means (84) on said compression sleeve are engageable by means for expanding the compression sleeve, said means engageable by means for expanding the compression sleeve being designed to fail when a predetermined amount of force is applied thereto by the means for expanding the compression sleeve. An arrangement according to claim 11, wherein said engageable means comprises tabs (84) formed in opposing ends of the compression sleeve (36). An arrangement according to any one of claims 1 to 7 or 10, wherein said compression sleeve (40) comprises a C-shaped structure (42), and wherein said means for locking the compression sleeve (40) comprises an arc-shaped structure (78) which engages the C-shaped compression sleeve (42) so as to form a relatively smooth and continuous profile around the outer circumference of the compression sleeve/locking means assembly. An arrangement according to any one of claims 1 to 7 or 10, wherein said compression sleeve (74) comprises a C-shaped strip (76) of material having teeth-like structures (82) on opposing ends thereof, and wherein said means for locking the compression sleeve comprises an arc-shaped structure (78) adapted to engage the teeth-like structures (82) on the opposing ends of the compression sleeve (76) to secure the C-shaped compression sleeve (76) into a locked position.

Inventors: SKINNER WILLIAM O, SKINNER, WILLIAM O.
Applicants: PRESS SEAL GASKET CORP, PRESS-SEAL GASKET CORPORATION
Application year: 1992
Main classification: F16L5
IPC codes: F16J15, F16L21, F16L5