Abstract: The invention relates to the use of a pulse oximetry sensor device. Based on standard methods for recording material labor activity during birth, reliable signals may be created so that a midwife obtains measuring values indicating clear information of maternal labor activity. The invention suggests the use of a pulse oximetry sensor device which measures the change in the oxygen content in the fetal blood during birth. The pulse oximetry sensor device is provided with a least one light emitter and at least one receiver, connected with an analyzing device, and attached to the leading part of the fetus for recording the maternal labor activity.

Abstract: A composite tool unit comprising a tool shank, a tool head a chuck, a drawbar which is slidable in the longitudinal direction of the tool shank and a pulling shank which projects from the tool head. The drawbar and pulling shank are engaged around by the chuck, which is disposed in the tool shank axially to slide between an opening position and a closure position. The tool shank comprises an inner conical face which tapers in the direction of the drawbar and co-operates with outer conical segments disposed on the clamping jaws. The zones of the drawbar 8 and pulling shank 8 of the tool head engaged around by the chuck have respective projections.