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(1981). In the past, several mechanisms were proposed to peel off permanent magnets. Fig. 1(a) is one example of a magnetic base, and Fig. 1(b) is the mechanism that temporarily weakens the magnetic force with an electromagnet. However, both of these require energy when changing the magnetic force. The IB magnet proposed here is an entirely new device, which can in principle peel off a permanent magnet with zero energy.
The configuration of the IB magnet is indicated in Fig. 2(a). The spring in Fig. 2(a) has the characteristic that at any position of a gap x from the magnet, an upward oriented force is produced that is the same as the downward oriented magnetic adhesive force. The non-linear characteristics of this kind of spring can be generated by multiple leaf springs that have shifted operational distances as in Fig. 3.
Because it is configured in this way, the IB magnet does not require any force at all for the upward/downward movement of the magnet. However, the force by which the frame is pressed to the steel plate fluctuates from the maximum value to zero. The IB magnet can be easily peeled off because of this effect.
This effect can be interpreted in the following way. In a single unit, when the permanent magnet is adhering to the steel plate, the magnetic potential energy that it holds is dissipated as heat. For that reason to peel it off requires energy equal to the dissipated energy. The IB magnet stores the energy that is lost at this time as the distortion energy of the spring, and makes the peeling off operation simple.
Photos. 1 and 2 are walking machines using IB magnets. The adhesive force of 1200 N can be easily switched by operating a lever. Photo.3 is a walking type wall adhering mobile robot using six IB magnets.
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Internally Balanced Magnet "IB Magnet"
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