BATTERIKORK MED GJENGE OG KONTROLLERT ENVEIS UTLUFTNING

A battery cap having threads and bleeding means for controlled bleeding of generated gasses, comprise a threaded portion of the cap being radially devided into a plurality of equal parts (2, 3) the plurality thereby being a multiple of 4 and the threads of one part being axially offset by 1/2 lead in relation to the threads of the adjacent part. The battery cap according to the invention furthermore comprises a lip (7) being biassed against the underside of the cap flange (12), an annular chamber (15) thereby being created between the lip (7) and the underside of the cap flange (12). Furthermore a plurality of passages (6) extending from the annular chamber (15) to the interior of the cap. When the cap is presses into a hole in a battery cover, the parts (2, 3) of the threaded portion will give after successively until the cap is pressed down in such a way that the shoulder (16) is abutting against the battery cover. Hereby the threads of one part will mesh in the corresponding threads of the cover, whereas the tips of the threads in the other part, will be pressed against the tips of the threads in the cover. The cap thereby is retained in the battery cover. By generation of gasses from the inside of the cap, the increased pressure of the internal will be conducted through the passages (6) to the annular chamber (15) and the lip (7) will open at a predetermined pressure. The lip (7) avoids dust and water in penetrating into the cap interior and the lip together with the passages (6), which have a minimum cross section, will make the battery cap fire retardent.