Instrument for measuring shearing stress-normal stress relationships of soils

Claim 1

A SOIL SHEARGRAPH COMPRISING, IN COMBINATION, A SHEAR HEAD MOUNTING A SHEAR RING HAVING RADIALLY-INWARDLY DIRECTED VANES ADAPTED TO BE FORCED INTO THE SOIL TO BE TESTED, A SHAFT AFFIXED AT ITS LOWER END TO SAID SHEAR HEAD, A RECORDING DRUM COAXIALLY RELATED TO SAID SHAFT AND INTO WHICH THE UPPER END OF THE SHAFT EXTENDS, BEARING MEANS INTERPOSED BETWEEN THE DRUM AND SHAFT AND PROVIDING FOR FRICTION-FREE RELATIVE AXIAL AND ROTATIONAL MOVEMENT THEREBETWEEN, SPRING MEANS INTERPOSED BETWEEN AND PROVIDING THE CONNECTION BETWEEN THE RECORDING DRUM AND THE SHEAR HEAD AND WHOSE AXIAL AND TORSIONAL SPRING RATES ARE SUCH AS TO BE CAPABLE OF IMPARTING AXIAL AND ROTATIONAL MOTION TO THE SHEAR HEAD DIRECTLY PROPORTIONAL TO SHEAR AND NORMAL STRESS APPLIED THERETO THROUGH THE SPRING MEANS, MEANS FOR APPLYING SUCH RELATIVE MOTION TO THE SHEAR HEAD, AND MEANS OPERATIVE BETWEEN THE SHEAR HEAD AND RECORDING DRUM FOR DIRECTLY PLOTTING SUCH RELATIVE MOTION AND THEREBY THE SHEAR-NORMAL STRESS RELATIONSHIPS OF THE TORSIONAL STRESSES CAUSING SOIL FAILURE AT DIFFERENT NORMAL STRESSES APPLIED TO SAID SHEAR HEAD.