Patent ID: 8201441

Claim:
Method for determination of the degree of hardness of semisolid materials ( 22 ) by measurement of the penetration depth ( 23 ) of a measuring body ( 5 , 8 ) which is dropped into the material to be tested under its own weight, wherein prior to the penetration measurement the measuring body ( 5 , 8 ) which is connected to a force/path sensor ( 20 ) is moved downwards from a initial position (S 25 ) which is located above the test material ( 22 ) to a return point (S 51 ) which is located within the test material ( 22 ), and the exact starting position ( 21 , s 41 ) of the surface of the test material ( 22 ) is determined and the measuring body ( 5 , 8 ) is arranged in the determined starting position ( 21 , s 41 ), characterized in that an adjusted force value (F Ber ) is determined prior or during the downward movement of the force/path sensor ( 20 ) from the initial position (S 25 ) to the return point (S 51 ) and for a plurality points in time (t 32-48 ) the force difference (ΔF 32 −ΔF 48 ) between the adjusted force value (F Ber ) and the measured force value (F 32 −F 48 ) of the respective point in time (ΔF 32 −ΔF 48 ) is determined and furthermore a zero time (t 41 ) is determined for which at least one of the following criteria i)-iii) is met: i) the force differences of consecutive measurements have the same algebraic sign effective from the zero time (t 41 ) and the time difference between the zero time (t 41 ) and one of the consecutive measurements exceeds a predetermined time limit, ii) the force differences of consecutive measurement have the same algebraic signs effective from the zero time (t 41 ) and the force difference of a measurement after the zero times (t 41 ) exceeds a predetermined force value, iii) the force differences of consecutive measurements have the same algebraic sign effective from the zero time (t 41 ) and a path difference between the zero time (t 41 ) path value and one of the consecutive measurements exceeds a predetermined path limit, wherein the position ( 21 , s 41 ) of the measuring body ( 5 , 8 ) at the zero time (t 41 ) is used as the exact starting position ( 21 , s 41 ) of the surface of the test material ( 22 ).