A recording soil penetrometer comprising a frame hav-   4,061,021 Dec. 6, 1977 ing upper and lower ends with a penetration probe extending downwardly from the lower end of the frame for penetration of the ground. A handle is operatively yieldably vertically movably mounted on the upper end of the frame for forcing the probe downwardly into the ground. A recording drum is rotatably mounted, about a vertical axis, on the frame and is adapted to have pressure sensitive recording paper mounted thereon. A ground-engaging apparatus is vertically movably mounted on the lower end of the frame. A rubber foot is provided on the lower end of the ground-engaging apparatus for engagement with the ground. A scriber is mounted on the upper end of the ground-engaging apparatus which is adapted to scribe the recording paper on the recording drum. A force link apparatus operatively interconnects the handle and the recording drum for causing rotation of the drum relative to the force required to cause the probe to penetrate the soil. The scriber scribes a depth-penetration resistance graph on the recording paper as the probe penetrates the soil.
Iowa State University Research Foundation, Inc.
Baldwin, William I. and Buchele, Wesley F., "Recording soil penetrometer" (1977). Iowa State University Patents. 9.