Abstract: In order to make castings from casting sand or another moldable mixture, a pressure surge wave is used which has upper and lower limit values which values have been established by an optimal selection of a pattern of pressures. The other moldable mixture comprises particles of raw material, binder, water, and, if need be, additives. The rise in pressure takes place with an increasing pressure gradient, dp/dt, of at least 50 atmospheres (absolute)/second. A minimum pressure of at least 2 atmospheres (absolute) is maintained for at least 0.01 second. The pressure drop takes place at a decreasing pressure gradient, -dp/dt, of up to about 2.0 atmospheres (absolute)/second. The disclosed values represent an optimalization, in view of a simple design and economy of operation, with a surprisingly good compacting.

Abstract: A hydraulically extensible crane boom includes a plurality of mutually innernested, telescopically associated inward and outward boom sections. Each section is made up of a pair of longitudinally extending, parallel, spaced apart upper structural shapes of substantial mass and strength, a relatively light top web integral with and extending between the upper structural shapes, a pair of longitudinally extending, mutually parallel, spaced apart lower structural shapes of substantial strength and mass, a relatively light bottom web integral with and extending between the lower structural members, and a pair of relatively light side webs each connected between one upper and one lower structural member. The distance between the lower pair of structural members is less than the distance between the upper pair of structural members.

Abstract: In order to make casting sand or another moldable mixture, a pressure surge wave is used which has upper and lower limit values which values have been established by an optimal selection of a pattern of pressures. The other moldable mixture comprises particles of raw material, binder, water, and, if need be, additives. The rise in pressure takes place with an increasing pressure gradient, dp/dt, of at least 50 atmospheres (absolute)/second. A minimum pressure of at least 2 atmospheres (absolute) is maintained for at least 0.01 second. The pressure drop takes place at a decreasing pressure gradient,--dp/dt, of up to about 2.0 atmospheres (absolute)/second. The disclosed values represent an optimalization, in view of a simple design and economy of operation, with a surprisingly good compacting.