US 2004/0163448 A1Published application

Method and device for determining the values of stiffness and dampening of surfaces

AssigneeTen Cate Thiolon B.V.

InventorsEdward Hage, Wynand Witbreuk, Geurt Bastiaan Slootweg, Marinus Hendrikus Olde Weghuis

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Abstract

The present invention relates to a method for determining the values of stiffness and dampening, in particular of surfaces for sports fields. The invention furthermore relates to a device for carrying out the aforesaid method. The object of the present invention is to provide a method and a device for determining the values of stiffness and dampening of an artificial grass lawn which provide a reliable measuring result in a quick and efficient manner, which device is furthermore user-friendly and easy to transport. In order to accomplish the aforesaid objective, the method according to the invention is characterized in that a block is placed on the surface in question, which block is struck by means of an electrically controlled excitator at an adjustable frequency interval, at a force which is sensed as a first signal by means of an acceleration sensor, after which the frequency-dependent transfer function is determined using the aforesaid signals, from which the frequency-dependent stiffness and dampening behaviour of the surface in question is subsequently determined.

Claims4

Dependent claims

A device for determining the values of stiffness and dampening, in particular of surfaces for sports fields comprising

a block which can be placed an 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, which masses are to he 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.

Dependencies are inferred from the claim text.