Abstract: A ball bearing (1) has an inner race (2) and an outer race (3). In order to prevent the rotating parts from being damaged when the bearing assembly fails, the bearing has emergency bearing surfaces (14, 15) which are concentric to the rotational axis (6) and of which one is a part of the rotating bearing race and the other is a part of the fixed bearing race. During normal operation, the emergency bearing surfaces (14, 15) are situated opposite one another with a relatively narrow gap (24) therebetween. But, in the event of failure, the surfaces (14, 15) engage and function as emergency bearing surfaces.

Abstract: A ball bearing (1) has an inner race (2) and an outer race (3). In order to prevent the rotating parts from being damaged when the bearing assembly fails, the bearing has emergency bearing surfaces (14, 15) which are concentric to the rotational axis (6) and of which one is a part of the rotating bearing race and the other is a part of the fixed bearing race. During normal operations the emergency bearing surfaces (14, 15) are situated opposite one another with a relatively narrow gap (24) therebetween. But, in the event of failure, the surfaces (14, 15) engage and function as emergency bearing surfaces.

Abstract: An elastic, essentially plate-shaped track foundation consists of closed-pored foamed and crosslinked rubber material, preferably EPDM rubber. The foaming and crosslinking preferably is performed in one working step.

Abstract: A refrigerating machine having a displacer reciprocable in a hollow space having a substantially-closed end for the refrigerating operation has a spring between the displacer and the substantially-closed end of the hollow space for damping vibration and noise of the displacer reciprocation.

Abstract: A displacer for low-temperature refrigerating machines having a regenerator disposed in a hollow space of the displacer, wherein the regenerator is formed at least in part of a sintered material, preferably sintered bronze spheres.