KRAFTINDIKATOR

Force indicator comprising a piece of material which, upon loading of the indicator, is subjected to material stresses. The piece of material has the property that it is changed to an increasing extent with increasing material stresses, so that the force to which the indicator has been subjected can be read off by the degree of the said material changes. The piece of material consists of a plastic element 2, preferably in the form of a foil, of the type of plastic that changes from a transparent state to an opaque state when the plastic is subjected to such stresses that exceed the material's yield point. A second element 4 is in contact with the plastic element 2 with a surface which is provided with irregularities 10, 11. The plastic element 2 is arranged to be stressed by the force that is to be recorded so that it is thereby pressed against the surface of the second element 4 and the irregularities on this. Upon the exceeding of a particular predetermined force, the first element is pressed against the irregularities in such a way that the material's yield stress is exceeded within certain areas of the irregularities. By this means, opaque areas are obtained which indicate the said exceeding of the force. The size of the force can thus be read off by means of the formation of the opaque areas.