Patent ID: 7336985

Claim:
A fetal heart rate electrode assembly, comprising: a drive tube having a distal end and a proximal end; a drive knob having a bore therethrough and secured to the proximal end of the drive tube, the drive knob comprising a body having a resiliently biased stop tab extending distally therefrom at an acute angle to the body, the stop tab having a distally facing abutment and a foot extending distally thereon; an electrode block located at the distal end of the drive tube and of similar outer diameter thereto, the electrode block bearing a spiral electrode protruding distally therefrom and a reference electrode, each of the electrodes being connected to one end of a wire of a wire pair extending proximally through the drive tube and through the drive knob, each wire of the wire pair extending at an opposing end thereof to a connector of smaller lateral extent than an interior diameter of the drive tube, wherein the connector comprises: a dielectric housing bearing a central contact proximate a presenting end thereof comprising an end of a wire of the wire pair and an annular contact surrounding the central contact and electrically isolated therefrom connected to another wire of the wire pair; and wherein the central contact and the annular contact comprise substantially coplanar end faces perpendicular to a longitudinal axis of the connector; and a guide tube having a distal end and a proximal end and of greater inner diameter than an outer diameter of the drive tube, wherein a portion of the drive tube is disposed within the guide tube and the electrode block and the electrodes are disposed within the distal end of the guide tube and the proximal end of the drive tube and the drive knob extend beyond the proximal end of the guide tube; wherein the foot of the stop tab is disposed between the drive tube and the guide tube with the distally facing abutment of the stop tab abutting a proximal end of the guide tube.