Abstract: A motor assisted swivel is disclosed which aids in proper rotation of a swivel in a tether system for animal testing. The swivel may have any number of fluid conduits or electrical or optical leads. A switching mechanism determines a direction of rotation of the tether and activates a motor to rotate the swivel in the direction of rotation. When rotation of the tether stops, further rotation of the swivel causes the switching mechanism to deactivate the motor. The switching mechanism may include a hinged connector with magnets on each side and reed switches to sense movement of the connector about its hinge.

Abstract: An oil tank sight glass monitor comprising a housing having an opening therein sized to receive the sight glass of an oil tank; an emitter for emitting a beam of light, the emitter being mounted to the housing on one side of the opening so that the beam of light is directed across the opening; a detector for detecting the beam of light generated by the emitter, the detector being mounted to the housing on the other side of the opening, in optical alignment with the emitter, so as to detect the beam of light emitted by the emitter; and an alarm for producing an audible sound when the detector fails to detect the beam of light generated by the emitter.