Abstract: An electronic level having a horizontal and/or a vertical transducer, each of which exhibits an effective impedance that is a function of the deviation of that transducer from a reference plane. Preferably, each transducer is an electrolytic transducer formed of a container partially filled with electrolytic liquid. Depending upon the general horizontal or vertical orientation of the level, one or the other transducer is connected to a drive signal generating circuit which supplies an output drive signal of a magnitude that is a function of the impedance of that transducer. This output drive signal is applied to a display driver which, in turn, drives an array of visual indicators in accordance with the output signal magnitude.

Abstract: An illuminated retractable tape measure has a casing which contains a coiled tape rule whose free end extends through an opening in the casing. A lock arrangement locks the tape against automatic retraction into the casing. In the lock arrangement, a locking member is mounted in the casing with an end thereof engageable with the tape to hold the same against a portion of the casing in a locking position. The end of the locking member is moved out of engagement with the tape when an unlocked position is established. A slide actuator pivots the lock member between its locked and unlocked positions. A small lamp or LED is incorporated in the casing for illuminating the ruling on the tape measure, and the actuator closes a switch when the actuator is moved to its locked position to light the lamp. This feature facilitates reading measurements on the tape measure, especially in adverse lighting conditions.

Abstract: An illuminated retractable tape measure has a casing which contains a coiled tape rule whose free end extends through an opening in the casing. A lock arrangement locks the tape against automatic retraction into the casing. In the lock arrangement, a locking member is mounted in the casing with an end thereof engageable with the tape to hold the same against a portion of the casing in a locking position. The end of the locking member is moved out of engagement with the tape when an unlocked position is established. A slide actuator pivots the lock member between its locked and unlocked positions. A small lamp or lamps is incorporated in the casing for illuminating the ruling on the tape measure, and the actuator closes a switch when the actuator is moved to its locked position to light the lamp. This feature facilitates reading measurements on the tape measure, especially in adverse lighting conditions.