the contact bridge 5 so that for example in the arrangement according to fig1 the upper part of the contact bridge 5 is only applied to the central fixed contact 2 while the lower part by the welded joint 8 is firmly connected to the central fixed contact 2 in this way despite the pointwise welding of the two parts there is still maintained a certain movability of both parts in relation to one another the central fixed contact 2 may be designed in the usual way as a rigid contact member in order to further increase the movability of the contact bridge in spite of the mechanical firm connection to the central fixed contact in the center part the central fixed contact may be designed to be more or less flexible which will be explained in greater detail hereinafter with reference to fig8 another possibility of increasing the movability of the contact bridge 5 in the center part and in spite of the firm connection is shown in fig5 in this type of embodiment the contact bridge 5 is welded to the central fixed contact 2 in the center at the point indicated by the reference numeral 8 above and below the welded joint however the contact bridge 5 is provided with slots 9 and 10 so that in spite of the firm connection between the contact bridge and the central fixed contact there is still achieved a certain movability of the contact bridge on the upper and the lower longitudinal sides thereof both the central fixed contact and the contact bridge however may also be designed to form one piece not requiring any subsequent connection of the two parts one such type of embodiment is shown in fig6 in which the.