Abstract: A spring brake cylinder having an emergency release device, particularly for rail vehicles, comprising: a housing; a spring piston for operating and releasing a spring brake; a normally locked, not self-locking threaded screw drive; an outer-radial sliding surface having a detent flank, the outer-radial sliding surface being an element of a rotatable part of the threaded screw drive, and the threaded screw drive having a pitch dimensioned such that the rotatable part carries out less than a complete rotation along its maximal axial adjusting stroke, and the detent flank being configured for locking the emergency release device; and a latch for interacting in a form-locking manner with the detent flank to lock the emergency release device, and for releasing the spring brake in the absence of a release pressure medium and thereby permitting axial movement of the spring piston.

Abstract: In order to achieve, in the case of a spring brake cylinder having an emergency release device, particularly for rail vehicles, and having a spring piston (8) which can be moved axially within a housing (1) and which, on the one hand, can be moved by means of an accumulator-type spring (9) for operating the brake in the event of a pressure drop and, on the other hand, can be moved by a spring pressure chamber (10), which can be acted upon by a pressure medium, for releasing this spring brake, as well as having a normally locked, not self-locking threaded screw drive (12) which is arranged in the flux of force between the spring piston (8) and an output-side piston rod (5) and which can be manually unlocked by way of a latch (13) assigned to the emergency release device, in order to be able to release the spring brake without any pressure medium, a reliable functioning of this emergency brake device in a simple manner, it is suggested that an outer-radial sliding surface (19) for the latch (13) held in contact