Abstract: A method and device for detecting opening of a passage in a bodily cavity, the device including an electric signal source; a first transducer for converting an electric signal from the electric signal source into an acoustic signal; a second transducer for reception of the acoustic signal; and where the first and the second transducer are placed on respective opposite sides of the obstruction in the cavity. In the method an acoustic signal is supplied at one side of the obstruction and received at the other side of the obstruction, when the passage is open.

Abstract: A detection system for monitoring safety equipment being worn by an individual for whom the wearing of such equipment is mandatory. The detection system is more specifically directed to individuals who are passing through an entryway into a designated area which requires the wearing of the equipment, and also to operators of machinery which require the same. In one embodiment, the detection system includes an infrared reflector which is fixed to a designated piece of equipment, for example, safety eyewear, an infrared transmitter and an infrared receiver which are located at one side of an entryway to the designated area and an alarm system which is activated when a person who is not wearing the specified equipment attempts to pass through the entryway into the designated area.

Abstract: The earplug inserted in the auditory canal is so designed that its inside end facing the tympanic membrane makes close contact with the surrounding hard bone structure, and its external end at the aperture of the auditory canal makes close contact with the surrounding tissue. The earplug has a head for connection with a communication system. A central channel conveys sound to the tympanic membrane. The mid-section of the earplug is furnished with a circumferential recess for receiving sound waves from the user's own voice through the surrounding soft tissue: and channels convey these sound waves to a microphone built into the earplug head.

Abstract: A disposable electromedical electrode comprises a supporting member including a dome-shaped central portion and a surrounding, annular and flat engagement portion as well as a connecting tab extending from the outer edge of the engagement portion and formed integrally with the supporting member. A continuous electrode coating is applied throughout the concave side of the central portion, the engagement portion and the connecting tab and is covered by an annular adhesive layer outside the engagement portion. The connecting tab is proportioned to allow direct and removable attachment of a connecting wire at a place spaced apart from the outer edge of the engagement portion. The electrode may be provided with a further electrode coating on the opposite side of the insulating supporting member to form a driven shield in use of the electrode.