| Patents for E21D 15 - Props; Chocks (3,432) |
|---|
| 02/24/1981 | US4252476 Hydraulically operated mine prop with safety valve |
| 02/24/1981 | US4252464 Device for limiting stresses in particular for buried tubular structures |
| 02/10/1981 | US4249837 Method of and apparatus for supporting an overburden |
| 02/03/1981 | CA1095092A1 Mining method |
| 12/24/1980 | WO1980002859A1 Mechanized support unit |
| 12/09/1980 | US4237769 Relief valves and mine props incorporating the same |
| 12/02/1980 | CA1090596A1 Prestressed elastic arched mine roof support |
| 11/12/1980 | EP0018448A1 Self-locking adjustable support devices |
| 10/01/1980 | EP0016747A1 Valve-system for controlling the extension of a hydraulic pit-prop |
| 09/23/1980 | CA1086180A1 Relief valves and mine props incorporating the same |
| 04/01/1980 | CA1074586A1 Mine roof supports |
| 03/11/1980 | US4192479 Aluminum, with protective jacket of hard metal |
| 01/29/1980 | US4185940 Method and system for supporting a roof |
| 11/13/1979 | CA1066071A2 Mining apparatus and method |
| 09/11/1979 | US4167361 Temporary mine roof prop |
| 08/22/1979 | EP0003707A1 Device for assembling two adjacent channel arch members of a gallery lining |
| 06/19/1979 | CA1056611A1 Method for removing resilient gallery lining frames |
| 03/27/1979 | US4146349 Mine roof support method and apparatus |
| 03/06/1979 | US4142449 Hydraulic mine prop |
| 11/07/1978 | CA1041778A1 Mining equipment |
| 09/19/1978 | US4114386 Method and device for removing resilient gallery lining frames in mining and tunnelling which consist of a number of section segments inserted one into another in a dissimilar manner |
| 09/05/1978 | US4111227 Pressure relief valve for hydraulic mine supporting elements |
| 09/05/1978 | CA1037724A1 Mine roof supports |
| 05/30/1978 | US4091838 Pressure relief valve |
| 04/04/1978 | US4081993 Device for measuring the magnitude and direction of compression forces |
| 02/07/1978 | US4072015 Borehole aerostatic ground support system |
| 10/04/1977 | US4052029 Compressible mine support |
| 01/25/1977 | US4004771 Ball-and-socket type connections for use with mining apparatus |
| 11/30/1976 | US3994467 Stilts for use in mine workings |
| 11/16/1976 | US3991578 Self-advancing mine roof supports |
| 10/12/1976 | US3985328 Prop-and-shoe assemblies of self-advancing mine roof-supports |
| 10/05/1976 | US3983789 Telescopic props |