The invention relates to a linear actor arrangement, comprising a linear actor with two ends whose distance is variable depending on an energizing of the linear actor, wherein each end is attached to a respective first or second coupling element which engage a coupling surface, wherein the coupling surface and the coupling elements exhibit mating surface structures in such a manner that the coupling elements are prevented from moving in a direction while being allowed to move in an opposite direction.

Design and construction is described for remotely-controllable variable MRI-compatible low-noise inductors and capacitors, each having a wide variation range and each occupying a volume of no more than 30 cubic centimeters. To optimize noise figure in 3-tesla medical MRI antenna arrays, an exemplar capacitor is connected in series following an antenna element and an exemplar inductor is connected in shunt following an exemplar capacitor. Exemplar Inductors are constructed as a pair of flux-coupled coils which are connected by a movable or rotatable contactor positioned by folded and nested stepping mechanisms. Exemplar inductors are constructed from two flux-coupled parallel solenoid coils or from two flux-coupled toroid-segment coils. Exemplar capacitors are designed and constructed in an analogous manner. Other miniature inductor and capacitor embodiments are possible. Miniature variable resistor embodiments can be constructed in a manner analogous to that of the capacitors.

Various mechanical drive devices, mechanical gears, combinations thereof and medical or dental treatment devices with such mechanical drive devices or gears are described. The mechanical drive devices and mechanical gears convert a unidirectional rotational movement received by a motor drive into a multidirectional movement, so that a tool-holding device of the treatment device can be induced to a multidirectional movement, in particular to a, preferably simultaneous, lifting and rotating movement or to a lifting and oscillating rotational movement with a reduced rotational speed.