only by the design of the clutch 26c it consists of an annular electromagnet coil piece 37c and an iron ring 62 which are axially spaced from each other when the clutch is not actuated these two parts surround the friction cylinder 56c which is attached to the pedestal 12c and are provided with radially extending support surfaces facing said cylinder the support surfaces axially secure a clamping sleeve 64 which is disposed in a resulting clearance between said two parts and the friction cylinder the clamping sleeve is crenellated it abuts on its radial outside on the inner surface of a sliding sleeve 66 and therefore cannot yield outwardly in the radial direction when axial pressure is exerted by the support surfaces upon electro magnetic movement of the magnet piece 37 toward the iron ring 62 along guiding pin 63 an abutment washer 65 on the pin forms a soft stop the axial pressure thus causes the clamping sleeve to be pressed against the surface of the friction cylinder which as before cuts in the harder resilient element 4c when the clutch is actuated the actions of the lower and upper resilient elements 3c 4c then complement each other in the sense of a parallel circuit the resonant frequency of the vibrating system formed of engine mount and engine thus is considerably shifted the mechanical equivalent circuit diagram for a different engine mount is shown in fig1 it comprises a pedestal 120 for receiving an engine and a mounting fixture 140 for attachment to a vehicle resilient element k ii 39 units an intermediate plate 127 with the mounting fixture and through resilient element k i 39 and a clutch 126 with the pedestal it is advisable.