Abstract: A longwall support control for controlling the movements of longwall support units in the longwall of a mine that includes a central control system and a plurality of control units, of which a separate control unit (mining shield control device) is locally and operationally associated to each longwall support unit. The mining shield control devices connect to the central control system and to one another via two bus lines, through which each of the mining shield control devices can be called up for inputting a control command from the central control system or an adjacent mining shield control device. The identical second bus line (parallel bus) permits retransmitting to the adjacent mining shield control device, incoming signals that do not store a code word assigned to the respectively addressed mining shield control device.

Abstract: In order to provide a two-stroke engine (100) which has an exhaust outlet (11) on the cylinder (10), with a silencer (12) arranged on the exhaust outlet (11), which silencer comprises a first chamber (13) and a second chamber (14) which are connected to the exhaust outlet (11) and through which exhaust gas produced in the cylinder (10) is able to flow, wherein the first chamber (13) is designed so that it is largely closed, and the exhaust gas can be guided through the second chamber (14) via an outlet on the silencer side into the open air, in which the disadvantages are avoided, and with which, in particular, a simple, compact unit is produced which at the same time effectively prevents damaging post-escape to the largest possible extent, it is proposed that the exhaust outlet (11) is designed with fixing means (16, 17, 18) on which a partition (15) is detachably arranged, which partition guides some of the exhaust gas into the first chamber (13) and some into the second chamber (14).

Abstract: A longwall support control for controlling the movements of longwall support units in the longwall of a mine that includes a central control system and a plurality of control units, of which a separate control unit (mining shield control device) is locally and operationally associated to each longwall support unit. Each mining shield control device comprises a switching element, which permits separating the bus line or lines in the mining shield control device. The mining control devices may also include signal amplifiers. An identical second bus line (parallel bus) permits retransmitting to the adjacent mining shield control device, incoming signals that do not store a code word assigned to the respectively addressed mining shield control device.