Abstract: An electrical field mapping system with an improved measurement and recording method which enables students to produce an electric field map of equipotential lines and electric field vectors. Measurements of an electric potential point and an electric field vector may be made by a three-probe sensor with pointer and displayed on voltmeters. An angular scale below the pointer may assist to measure the direction of the electric field. An X-Y transfer mechanism transfers the location of the three-probe sensor, from the space around electrodes, to a marker at a corresponding location in the recording area. Recordings of the field data are made by markers with different impressions and may include an electric field vector, equipotential line segment, and electric potential point.

Abstract: A sliding door rotary latch system includes a handle assembly mounted on the sliding door adjacent its leading edge, a rotary latch assembly and locking mechanism mounted on the front post of the door frame cooperating with a strike bar on the handle assembly selectively to latch the sliding door in its fully closed position and a rear latch plate mounted on the back post of the door frame cooperating with the handle assembly selectively to latch the sliding door in its fully open position. The door mounted handle assembly includes an outer pivotal handle, an inner pivotal handle, and an inner actuation mechanism operative to allow either handle independently of the other to actuate either a pivotal front cam actuator arm or a rear pivotal latch independent of the other. Either handle may be held in its pivoted position toward the direction of sliding movement of the door during that sliding movement without adversely effecting the latching action when the door is either fully closed or opened.

Abstract: A nested paddle lock assembly comprises inside and outside pan assemblies mounted in alignment with one another on a door and respectively having inside and outside selectively pivotal paddle handles, slide means in said door selectively linearly actuated by either handle when pulled, pivotal lever means pivoted by said linearly moving slide means upon handle actuation to unlatch said door, spring means to return the pivotal lever means, slide means and handles to their respective normally closed positions and lock means selectively actuated from inside or outside the door either to lock the door by obstructing slide means movement or to unlock the door by allowing slide means movement.

Abstract: A tool-operated latch has a body which is mountable on the back side of a door panel adjacent an elongate opening and a hole formed through the door panel. An elongate latch lever is pivotally carried by the body and is movable between a latched position wherein the latch lever is nested with respect to the elongate door opening, and an unlatched position wherein the latch lever is extended with respect to the elongate door opening. A tool-operable actuator is journaled by the door panel hole and by the latch body, and is movable by a specially configured tool between locked and unlocked positions. A pawl is pivotally carried by the body for movement between a retaining position wherein it engages the latch lever to releasably retain the latch lever in its nested, latched position, and a releasing position wherein the pawl releases the latch lever thereby permitting the latch lever to be moved to its unlatched, extended position.