Patent ID: 6962073

Claim:
A device for determining the values of stiffness and dampening of surfaces for sports fields comprising a block which can be placed on a surface whose values of stiffness and dampening are to be determined, an excitator for striking said block with input signals at an adjustable frequency interval, as well as sensor means for sensing output signals resulting from said input signals and determining the values of stiffness and dampening of said surface based an said resulting output signals, characterized in that said excitator comprising two masses that are vibrated by the same one driving unit, which masses are to be vibrated in a springing manner with respect to each other, is suspended, by means of weak springs, in a frame, which is supported, via an intermediate part, on said block and wherein the excitator is guided in the frame in such a manner that unimpeded movement of the moving masses is only possible in a direction perpendicularly to the block, wherein the lower excitator mass co-operates, via a slender bar, with the intermediate part and wherein means are present for varying the mass on the slender bar, wherein the intermediate part is connected to the block via a force sensor and a guide.