Abstract: A melt withdrawal device for melt furnaces for charging casting machines has a melt conveying pump (1) comprised of a pump tube (2) forming a lower melt inlet (3) and an upper melt outlet (4) and of a pump shaft (5) extending inside the pump tube (2) and carrying a pump rotor (6). To achieve a melt conveyance which is largely independent of the melt level variations inside the melt furnace and can thus be dosed property, a charging means (7) for keeping constant the pump head (h) is provided before the melt conveying pump (1), which charging means (7) comprises a charging tank (8) accommodating the pump tube (2) with the melt inlet (3) and a charging pump (10) capable of filling the charging tank (8) with melt up to a melt overflow (9) determining the charging height, where the delivery rate of the charging pump (10) exceeds that of the conveying pump (1).

Abstract: In a one-half part of a sliding surface bearing comprising a bearing half-shell (1) and at least one stop collar (2), the stop collar (2) constitutes a separate end flange and has mounting extensions (5), which protrude toward the bearing half-shell (1) and extends into fitting openings (3) of the bearing half-shell (1), which openings are open at the end face.To permit relatively large radii at the transition between the bearing half-shells (1) and the stop collar (2), the fitting openings (3) have an undercut (4), which is effective in an axial direction, and the mounting extensions (3) of the stop collar (2) extend behind the undercuts (4) and are axially aligned.

Abstract: In a sliding surface layer, a bearing metal layer is provided on the inside surface of a backing shell and is formed on its inside surface with elongate recesses, which extend in the peripheral direction of the bearing and are distributed over the axial extent of the sliding surface of the bearings. These elongate recesses contain a relatively soft bearing material. In order to increase the fatigue limit and the wear resistance, the softer bearing material constitutes a continuous covering layer, which has on the lands of the inside surface of the bearing metal layer a thickness that is not in excess of 1.5 times the depth of the elongate recesses. The axial center spacing of the elongate recesses should not exceed an upper limit a.sub.o =500+0.5 d+0.01 d.sup.2 in micrometers, if d is the bearing diameter in micrometers.

Abstract: In a composite sliding surface bearing comprising a load-carrying backing shell, a bearing metal layer provided on the inside surface of the backing shell, and a sliding surface layer provided in the inside surface of the bearing metal layer, an interlayer is provided between the sliding surface layer and the bearing metal layer. In order to minimize the deleterious influence of the interlayer on the life of the composite sliding surface bearing, the bearing metal layer is formed on that surface which carries the interlayer with a profile having a depth which amounts to at least 5 micrometers and exceeds 1.5 times the thickness of the interlayer, which follows the profiled shape of the bearing metal layer.

Abstract: The friction conditions in a hydrodynamic surface bearing having a bearing metal layer in which no softer bearing metal is embedded are substantially improved in that the bearing surface is formed with grooves, which are distributed over the width of the bearing and include with the direction of movement in the bearing an angle not in excess of 20.degree.. These grooves cooperate with the moving element to be received in the bearing so as to define passages which ensure that a minimum hydrodynamic pressure will be built up in the lubricant.

Abstract: A sliding surface bearings for heavy loads comprises a backing shell and a bearing metal layer provided on said backing shell and formed with axially spaced apart grooves, which extend at an acute angle of at most 15 degrees to the peripheral direction substantially around the axis of the bearing and contain a bearing which is softer than said bearing layer. In order to ensure that the bearing will have a long life, the axial center spacing of the grooves does not exceed an upper limita.sub.o =250+0.5d+001 d.sup.2where a.sub.o is expressed in micrometers and d is the diameter of the bearing surface in millimeters, and said center spacing in any case does not exceed 10 mm.

Abstract: The bearing comprises a bearing metal layer, a sliding-surface layer consisting of a lead alloy which contains copper and tin, and an additional layer which is disposed between said bearing metal layer and said sliding-surface layer and adjoins the latter and consists of a lead-copper alloy which is initially free from tin. Any tin which is subsequently contained in said additional layer is completely bonded to said copper in said additional layer in the form of a copper-tin phase. In the manufacture of the bearing, the sliding-surface layer is applied to said additional layer when the latter is free from tin and the bearing may be subjected to a heat treatment at an elevated temperature below 183.degree. whereby tin from said sliding-surface layer is caused to enter said initially tin-free additional layer and to be bonded to copper in said additional layer in the form of a copper-tin phase.