Abstract: An iron alloy material for casting includes 0.3 to 3.5 mass% of C, 0.1 to 3.0 mass% of Si, 26.0 to 42.0 mass% of Ni, 0.02 to 0.50 mass% of Sb, and a balance that is Fe and an inevitable impurity/impurities.

Abstract: A split wedge body, which has a curved inner surface, is formed gradually thicker from a tip portion to a terminal end portion thereof, and is made to cover the outer peripheral surface of a CFRP cable to thereby enclose the outer peripheral surface of the CFRP cable over a prescribed length thereof. A gap extending in the longitudinal direction is assured between end faces that oppose each other when a plurality of the split wedge bodies are arranged on the outer peripheral surface of the CFRP cable. The gap has an inclined portion that runs along a valley of the CFRP cable enclosed by the split wedge bodies.

Abstract: An inner peripheral portion of a receiving frame and an outer peripheral portion of a lid body each include first and second surface parts. In the closed-lid state, the first surface part of the lid body is supported by the first surface part of the frame, each of which include a gentle gradient. The second surface parts of the lid body and the receiving frame are pressed against each other by a force caused by elastic deformation of at least one of the outer peripheral portion of the lid body and the inner peripheral portion of the receiving frame. The second surface part of the receiving frame includes a steeper gradient than the first surface part of the receiving frame by reducing its diameter toward a downward direction of the receiving frame.

Abstract: An underground structure cover comprises a cover body (10) and a receiving frame (20) arranged so that the cover body is fitted in and supported by the receiving frame in the manner that an inclined surface (11) of the outer circumference of the body meets an inclined surface (21) of the inner circumference of the frame. The inclined surfaces (11, 21) each have an upper inclined surface (11a, 21a) and a lower inclined surface (11b, 21b), and the lower inclined surfaces (11b, 21b) are steeper than the upper inclined surfaces (11a, 21a). The body (10) is fitted in and supported by the part (20) at the upper inclined surfaces (11a, 21a) and the lower inclined surfaces (11b, 21b). By this, the body is prevented from being wedged into the frame too deeply and also from becoming inclined with respect to the frame or riding up.

Abstract: A cover assembly includes a support frame (20) fixed to a utility access hole and a rounded cover (10) fitted into the support frame. The support frame is provided in its upper portion with an S-curved inner peripheral surface (20b) having a convex curved surface portion (21) and a concave curved surface portion (22) that continues to the convex curved surface portion and is formed thereabove. The cover has an S-curved peripheral surface (10b) that is substantially complementary in shape to the S-curved inner peripheral surface of the support frame. When the access hole is closed by the cover, the cover is smoothly fitted into the support frame due to a guide function of the S-curved inner peripheral surface of the support frame.

Abstract: A cover assembly includes a support frame (20) fixed to a utility access hole and a rounded cover (10) fitted into the support frame. The support frame is provided in its upper portion with an S-curved inner peripheral surface (20b) having a convex curved surface portion (21) and a concave curved surface portion (22) that continues to the convex curved surface portion and is formed thereabove. The cover has an S-curved peripheral surface (10b) that is substantially complementary in shape to the S-curved inner peripheral surface of the support frame. When the access hole is closed by the cover, the cover is smoothly fitted into the support frame due to a guide function of the S-curved inner peripheral surface of the support frame.

Abstract: A cover for underground structures has a large number of mutually independent projections of the same size and shape uniformly provided on its surface, while small protrusions of the same size and shape are formed on the upper surfaces of some or all of these projections. On top of these small protrusions are formed even smaller protrusions of the same size and shape as the topmost protrusions. Spacing between one large projection and another, between one small protrusion and another, or between one small protrusion and a projection having no small protrusion on its top is set at the optimum distance, and the size of the topmost protrusions is also designed in a shape to fit an optimum size to ensure good skid-prevention effect on tires of vehicles passing over the cover, especially in bad weather over a long period of time, no matter where the cover is installed.

Abstract: A cover for underground structures, its cover body, and its frame designed to quickly discharge accumulations of rainwater and dirt so as to prevent slipping and skidding from increasing due to these accumulations. The cover body has a multiplicity of patterns of projections and depressions on its surface, one projection independent of another, so that the upper surface of each projection is on about the same level as that of the frame with the depressions formed to surround each of these depressions. The depressions are constructed to become gradually deeper from the central part of the cover body toward the periphery, while the frame also has depressions set up on part or all of its upper surface in a circumferential direction with discharge guides sloping up toward the outer periphery of the frame. The cover for underground structures is made up of a set of the cover body and the frame.