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| US4097171 | 16 sept. 1977 | 27 juin 1978 | | Manhole cover support ring |
| US4149816 | 6 févr. 1978 | 17 avr. 1979 | | Metal shaft cover frame |
| US4225266 | 1 nov. 1978 | 30 sept. 1980 | | Method and apparatus for adjusting the elevation of manhole covers |
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| US4273467 | 25 juin 1979 | 16 juin 1981 | Cremo Supply Ltd. | Adjustable manhole cover support |
| US4281944 | 10 sept. 1979 | 4 août 1981 | | Manhole cover support |
| US4302126 | 27 déc. 1979 | 24 nov. 1981 | | Manhole cover support ring |
| US4582450 | 10 oct. 1984 | 15 avr. 1986 | | Universal manhole adjusting ring |
| US4844402 | 1 juil. 1988 | 4 juil. 1989 | | Form for a mortar cap |
| US4867600 | 1 juin 1988 | 19 sept. 1989 | | Polygonal manhole cover support |
| US4867601 | 15 juin 1988 | 19 sept. 1989 | | Sturdy adjustable manhole cover support |
| US4872780 | 15 juin 1988 | 10 oct. 1989 | | Manhole cover support with box flanging |
| US4927290 | 11 juil. 1989 | 22 mai 1990 | | Manhole cover support resistant to water infiltration |
| US4963053 | 6 juin 1989 | 16 oct. 1990 | | Multicomponent wales and bases for manhole cover supports |
| US4966489 | 6 juin 1989 | 30 oct. 1990 | | Manhole cover support having interbraced top members |
| US4969770 | 6 juin 1989 | 13 nov. 1990 | | Manhole cover support with topside flange |
| US4969771 | 14 juin 1989 | 13 nov. 1990 | | Manhole cover support having enhanced grip |
| US5021261 | 1 févr. 1990 | 4 juin 1991 | | Process for making a manhole cover support having enhanced grip |
| US5205668 | 29 mars 1991 | 27 avr. 1993 | AT&T Bell Laboratories | Manhole adapter |
| US5211504 | 31 janv. 1991 | 18 mai 1993 | | Adjustable manhole top |
| US5221155 | 24 sept. 1991 | 22 juin 1993 | Umar, Inc. | Vertically adjustable manhole adjusting ring section |
| US5308189 | 15 juin 1992 | 3 mai 1994 | | Gripping device for retaining a ring member supporting a manhole cover |
| US5326188 | 8 déc. 1992 | 5 juil. 1994 | | Anchor for manhole cover support |
| US5344253 | 1 sept. 1993 | 6 sept. 1994 | | Adjustable manhole cover |
| US5564855 | 31 mai 1994 | 15 oct. 1996 | National Polymers Inc | Height adjustment ring for manhole cover frame |
| US5611640 | 22 août 1995 | 18 mars 1997 | | Method and apparatus for anchoring a utility grate cover |
| US5628152 | 16 août 1995 | 13 mai 1997 | | Adjustable manhole cover support with shield |
| US5697729 | 21 août 1995 | 16 déc. 1997 | | Anchor for utility access hole support insert |
| US5944442 | 7 févr. 1997 | 31 août 1999 | Anjowa, Inc. | Manhole extender ring system and method of use |
| US5956905 | 6 févr. 1997 | 28 sept. 1999 | | Manhole adjusting extension member |
| US6007270 | 12 mai 1997 | 28 déc. 1999 | | Manhole frame assembly |
| US6371687 | 7 févr. 2000 | 16 avr. 2002 | | Method and apparatus for leveling manhole cover frames |
| US6527476 | 2 déc. 1999 | 4 mars 2003 | Tycom (US) Inc. | Non-sinking manhole assembly for below ground liquid storage tanks |
| US6811350 | 7 oct. 2003 | 2 nov. 2004 | | Method and apparatus for adjusting the height and inclination of roadway and greenway appurtenances |
| US6953302 | 23 juil. 2004 | 11 oct. 2005 | | Adjustment riser for a manhole frame |
| US6997639 | 27 oct. 2004 | 14 févr. 2006 | | Method and apparatus for adjusting the height and inclination of roadway and greenway appurtenances |
| USRE34550 | 11 juin 1992 | 22 févr. 1994 | | Sturdy adjustable manhole cover support |
