Abstract: A safety helmet with a helmet shell, with a bearing ring, with a rotatable actuating element (14) and with a transmission unit (15.1, 15.2). The transmission unit (15.1, 15.2) transmits a rotation of the actuating element to the bearing ring, so that the head size provided is changed. A helmet shell-side transmission piece (15.1) is non-rotatably connected to the actuating element (14) such that they rotate in unison, and a bearing ring-side transmission piece (15.2) is connected mechanically to the bearing ring. The helmet shell-side transmission piece (15.1) can move both relative to the actuating element (14) and relative to the bearing ring-side transmission piece (15.2) linearly in two opposite directions. The distance between the actuating element (14) and the bearing ring can be changed thereby.

Abstract: A safety helmet with a helmet shell, with a bearing ring, with a rotatable actuating element (14) and with a transmission unit (15.1, 15.2). The transmission unit (15.1, 15.2) transmits a rotation of the actuating element to the bearing ring, so that the head size provided is changed. A helmet shell-side transmission piece (15.1) is non-rotatably connected to the actuating element (14) such that they rotate in unison, and a bearing ring-side transmission piece (15.2) is connected mechanically to the bearing ring. The helmet shell-side transmission piece (15.1) can move both relative to the actuating element (14) and relative to the bearing ring-side transmission piece (15.2) linearly in two opposite directions. The distance between the actuating element (14) and the bearing ring can be changed thereby.

Abstract: A communication device (100), for monitoring breathing, includes a microphone unit (110), a monitoring unit (120) and an output unit (130). The microphone unit receives an acoustic signal (105), which indicates the breath sounds (350) of a communication device user (102), from a surrounding area (112) of the microphone unit, and converts same into a digital input signal (114). The monitoring unit is configured to receive the digital input signal and to split the indicated breath sounds into individual breaths (124) based on an amplitude- and/or frequency-dependent pattern recognition (122) and to determine a respective breath duration (125) of a breath. The monitoring unit triggers a breath alarm state (126) of the communication device as a function of a consecutive sequence of breath durations. The output unit is configured to output an alarm output (132) indicating the breath alarm state after a triggering of the breath alarm state.

Abstract: A safety helmet with a helmet shell, with a bearing ring, with a rotatable actuating element (14) and with a transmission unit (15.1, 15.2). The transmission unit (15.1, 15.2) transmits a rotation of the actuating element to the bearing ring, so that the head size provided is changed. A helmet shell-side transmission piece (15.1) is non-rotatably connected to the actuating element (14) such that they rotate in unison, and a bearing ring-side transmission piece (15.2) is connected mechanically to the bearing ring. The helmet shell-side transmission piece (15.1) can move both relative to the actuating element (14) and relative to the bearing ring-side transmission piece (15.2) linearly in two opposite directions. The distance between the actuating element (14) and the bearing ring can be changed thereby.

Abstract: A connection module (10) for installation in a closed breathing circuit of a closed-circuit breathing apparatus (1000), includes an inlet port (12), for connection to a first closed circuit element, an outlet port (14), for connection to a second closed circuit element, a maintenance fluid inlet (16), and a maintenance fluid outlet (18). A maintenance device may be provided with the connection module and a controller (30) and control module regulated valves (40). Maintenance fluid is circulated through the closed breathing circuit by the controller and valves in a state in which the connection module (10) is installed in the closed-circuit breathing apparatus.

Abstract: A connection module (10) for installation in a closed breathing circuit of a closed-circuit breathing apparatus (1000), includes an inlet port (12), for connection to a first closed circuit element, an outlet port (14), for connection to a second closed circuit element, a maintenance fluid inlet (16), and a maintenance fluid outlet (18). A maintenance device may be provided with the connection module and a controller (30) and control module regulated valves (40). Maintenance fluid is circulated through the closed breathing circuit by the controller and valves in a state in which the connection module (10) is installed in the closed-circuit breathing apparatus.