Improvements in or relating to magnetic devices for converting rotary motion into reciprocating motion or conversely

摘要

747,727. Magnetic couplings; magnetic structures. PHILIPS ELECTRICAL INDUSTRIES, Ltd. March 3, 1953 [March 6, 1952], No. 5871/53. Classes 35 and 38 (2). A magnetic device for converting rotary motion in one direction into reciprocating motion, or vice versa, comprises two members each having a magnetic system comprising permanent magnetic poles, which, along a line connecting each such pole with the adjacent pole, are of alternate polarity, the conversion of motion being due to the interaction of the fields of the two said members. Fig. 1 shows a sectional view of such a device having a rotary member 1 comprising a disc-shaped element 3 of permanent magnetic material axially polarized and a second member 2 having a disc 4 similar to disc 3. The member 2 is constrained from following the rotating force of the member 1 by two springs 6, 61 which permit the member 1 to reciprocate as the member 1 rotates. The springs 6, 61 may be replaced by a diaphragm forming part of a diaphragm pump or a siren. In a modification, the element of the reciprocating member 2 is arranged between two elements of the rotary members 1 as in Fig. 3 (not shown). Fig. 4 shows a rotary member 1 carrying two cylindrical permanent magnets 12, 13 while the reciprocating member 2 has an external permanent magnet 14 which is so carried by a diaphragm 7 that it can reciprocate axially along the outer peripheral surfaces of the magnets 12, 13 as the latter rotate. Besides the diaphragm 7 there may also be a stationary braking permanent magnet 15 surrounding the reciprocating magnet 14. In a further modification shown in Fig. 5, the member 1 is stationary and it has a core 20 with an A.C. fed coil 19 on its central limb and two permanent magnets 12, 13 located as shown, while the member 2 is arranged to reciprocate and rotate under the action of the electromagnet and permanent magnets. Also, instead of having rectangularly shaped poles for the permanent magnets, there may be zig-zag poles having the appropriate N and S polarity and neutral zones. The permanent magnetic material of the magnetic circuits has a retentivity B which, measured in Gauss, is smaller than four times the coercive field strength B H C measured in Oersted. Specifications 708,127, 745,911 and 747,724 are referred to.