Electro-magnetic selection device for the needles of a knitting machine

Claim 1

Electromagnetic selection device for the needles of a knitting machine, comprising jacks for raising the needles, cam means for moving the jacks upward when in selected position, a selector for each said jack movable laterally of the direction of travel of the needles to position said jack in or out of selected position, channel means guiding said selectors and comprising successively in the direction of movement of said selectors a portion with converging side walls, a throat and a portion with diverging side walls, an electromagnetic selection system at said throat of said channel means, said electromagnetic selection system comprising opposite pairs of pole pieces disposed at the side walls of said channel means for drawing said selectors selectively to one or the other side of said channel means, and a permanent magnet system in the portion of said channel means with diverging side walls for maintaining said selectors at the side of said channel means to which they have been drawn by said electromagnetic selection system, said permanent magnet system comprising a single permanent magnet disposed transversely of and beneath said channel means portion with diverging sidE walls, said permanent magnet being vertically magnetized and having an upper face of one polarity and a lower face of the opposite polarity, a pair of spaced superposed pole pieces of opposite polarity at each of the diverging side walls of said diverging portion of said channel means, and two soft iron yoke systems, one of said yoke systems being connected to one pole piece of one polarity of each of said pair of pole pieces of said permanent magnet system and having a portion contiguous to the upper face of said permanent magnet, the other of said yoke systems being connected the other pole piece of opposite polarity of each of said pair of pole pieces of said permanent magnet system and having a portion contiguous to the lower face of said permanent magnet, whereby the total flux of said single permanent magnet is distributed between the pairs of pole pieces at opposite sides of said portion of said channel means with diverging side walls according to the distribution of said selectors at one or the other side wall.