Magnetic miniature switches of this design are popular for use in do-it-yourself kits, in craftsmen’s and industrial machines because of their compact shape and universally cost-saving application. These are machines which are frequently moved around in their places of use. It may also happen that these machines are exposed to vibration when the workpiece is put down violently. This may cause unwanted automatic starting of the machine, if plugged in. The reason for this is the heavy armature of such switches which descend after a shock, and thereby shut the contacts. For this reason a patented accessory device was developed which will effectively prevent the unintentional switching on.
