Abstract: A portable, electrically energized, cordless grass trimmer device is disclosed having a rotatable hub which is adapted to alternatively mount, for substantially balanced rotation therewith, a flexible cutter strip and a line cutter and mechanical counterbalance.

Abstract: A seismic communications system including a central control and recording station and a plurality of remote data acquisition stations, the stations being approximately in line and connected to each other by one or two transmission lines. One line is all that is necessary if the central station is at one end of the line of stations; however, if the central station has some acquisition stations upstream and some downstream therefrom, two lines are required. Coded central strobe bursts put on a transmission line at the central station successively cause insertion of digital seismic data from successively more remote acquisition stations, the data being time slotted after each central station strobe burst so that reverse transmissions do not interfere with subsequent signal propagations emanating from the central station. Twin lead is preferably used for the transmission lines. Power shut down, except for a pilot receiver, is accomplished at each acquisition station between recording cycles.

Abstract: A high contact density circular connector capable of receiving, indexing, and fixedly holding a multi-element probe tip used to test the quality of tapered fastener holes. The outer surface of the probe tip has a multiplicity of conductive segments, which are covered by a thin layer of insulation at the end to be inserted into the holes being inspected. When the probe tip is inserted into a hole, capacitors are formed between the conductive segments on the probe tip and the metallic walls of the hole, which can be measured for value and correlated in a computer to disclose hole characteristics such as size, shape, and smoothness. The circular connector is the means by which probe measurements are transferred from the tip into a coaxial cable, for transmission to the electronic processor without molesting the minute capacitance measurements.