Abstract: The invention relates to an ion filter and a method for the production of the ion filter. The ion filter comprises a plurality of elongated solid, rod assemblies. Typically, four rod assemblies, corresponding to four rod electrodes, are utilized. Each rod assembly has a curved rod surface, and at least two abutment surfaces. In one embodiment, the rod is hyperbolic in curvature. These surfaces are formed with one profiled grinding tool simultaneously in such a manner and angle of contact from a processing direction such that no undercuts are formed from this processing direction. The abutment surfaces are shaped such that one abutment surface of one rod assembly can be aligned with another abutment surface of another rod assembly when the rod surfaces are directed toward a longitudinal axis located in the interior of the ion filter. The rod assemblies are electrically insulated from each other with an insulating piece adhesively bonded to each rod assembly.

Abstract: A coupling for two adjacent rail sections of a model railway has a bed member with rails and conductor rail held thereon and downwardly extending projections electrically connected to the rail and conductor rail. A coupling member is arranged beneath the bed members and has two upwardly opening, electrically conductive, elastic, locking elements that engage the extending projections such that projections on adjacent rail sections are mechanically and electrically connected. One locking element comprises upwardly protruding elastic tongues that interlock with the projections, and the other locking element comprises two parallel spring wires, connected by a contact spring and set apart by spacers such that projections are insertable there between. A locking element, on the underside of the coupling member, forms the elastic tongues. A connecting element, resting against the locking element, protrudes on both sides of the coupling member in the form of a contact lug.