forces exerted on tooth 11 whose external portion 21 is slightly withdrawn from the facing face of the carrier arm the removable character of teeth 11 and blades 15 16 makes it possible to replace damaged parts and to substitute for present parts parts having characteristics shape nature of the material better adapted to the work contemplated at the present time such substitution is not possible especially with the teeth of known concrete crushers which are formed of weld deposits superimposed on the arms of the crusher these teeth have to be further periodically regenerated because of wear it should be noted that with the present invention when the concrete crusher 4 5 has completely broken for example a reinforced concrete beam it is then in the completely closed position fig1 and the shears 5 14 are in the maximum open position so it is immediately ready to grip and section the reinforcing bars on the contrary with known crushers it is necessary to open the crusher completely since the shears are situated at the bottom similarly at the end of shearing the crusher is in the maximum open position therefore ready to act it should also be noted that in the crusher of the.