| 摘要 |
A pointer resetting mechanism for a magnet disc operated gauge mainly adapted for use in vehicles is made up of a coil spring particularly housed together with a floatable magnet disc for protection in a sealed shelter case and at least an auxiliary magnet received in one of a tubular columns in a lower case of the shelter case. The spring has one end fixed to a pointer shaft and the other end secured to a retaining means disposed on the case. Around the sealed shelter case is wrapped around induction copper wires. When an electric current appears in the copper wires, the magnet disc floating in damping oil is forced by induced magnetism to rotate in the shelter case and when the electric current is removed the pointer can be automatically reset by way of the mechanical biasing force of the coil spring. Furthermore, the auxiliary magnet is used to make the pointer operate more stable at its initial position at where the coil spring can not produce enough tension to firmly hold the pointer in position. When the pointer is moved within or over a half circle range, the coil spring is extended in such a manner that it will produce larger tension to hold the pointer, the auxiliary magnet can constantly help the pointer to overcome the tension by attracting the magnet disc to spin clockwisely. When the pointer moves back to its initial position, the auxiliary magnet can also exert force on the magnet disc so as to help the pointer move smoothly backwards. |
