Abstract: A sealing system provides for plugging holes in a ferromagnetic tank structure. A tripod has variable length legs for placing on a curved or irregular surface of the tank structure. A permanent magnet assembly is attached to each one of the variable length legs for removably attaching the legs individually to the ferromagnetic tank structure. An actuator is mounted in the tripod for positioning over the hole for movement generally perpendicular to the tank structure in which the hole is located. A clamping plug is mounted on the actuator for insertion into and sealing the hole.

Abstract: A magnetic gripper provides a support for releasable attachment to a ferromagnetic surface. A magnet adheres the gripper to the ferromagnetic surface. A frame is rotatably attached to the magnet where the frame defines cam surfaces to raise and lower the magnet from the ferromagnetic surface. An ear extends from the magnet to engage the ferromagnetic surface at a location spaced from the cam surfaces so that an end of the magnet near the ear can be first disengaged from the ferromagnetic surface, causing an air gap between the magnet and the ferromagnetic surface. The remainder of the magnet is sequentially disengaged from the surface as the cam surface is rotated. A foot support may be rotatably mounted to the frame so that a user can stand on the gripper to perform maintenance and repairs on the structure defined by the ferromagnetic surface.

Abstract: A temporary seal or patch assembly prevents the escape of contents, e.g., fluids and the like, from within a container having a breach therethrough until the contents can be removed and/or a repair effected. A frame that supports a sealing bladder can be positioned over the breach and the frame is then attached to the container surface, which must be of a ferromagnet material, by using switchable permanent magnets. The permanent magnets are designed to have a first condition that is not attracted to the ferromagnetic surface and a second conditions whereby the magnets are attracted to the surface with sufficient force to support the seal assembly on the surface. Latching devices may be attached to the frame and engage the container surface with hardened pins to prevent the lateral movement of the seal assembly along the container surface from external forces such as fluid drag or gravity.

Abstract: A climbing apparatus is provided for climbing ferromagnetic surfaces, such as storage tanks and steel frame structures. A magnet assembly is rotatably mounted in a frame assembly. The frame assembly provides a pair of cam surfaces having different dimensions so that, when the frame is rotated, the cam surfaces contact the ferromagnetic surface to separate the magnet assembly from the surface. The different cam dimensions enable one side of the magnet at a time to be detached from the surface to reduce the effort needed to disengage the climbing apparatus. The cam surface also provides for smoothly attaching the apparatus. A hardened dowel pin is also attached to the frame and the pointed end of the dowel engages the surface when the magnet is attached to the surface to prevent downward sliding movement of the assembly under the weight of the user.