A selection device for oscillating jacks in a circular knitting machine comprising selection levers pivotal between an active position in which the jacks are radially thrust by a thrust profile of the levers, and an inactive position. The levers are moved into one of these positions by engagement of a control profile of the levers by the butts and are held in this position by a permanent magnet. The flux of the magnet can be neutralized temporarily by program-controlled windings to permit release of a selected lever whereby the lever is moved into its other position by means of a bias.
An electromagnetic selector device comprising a single permanent magnet and a plurality of electromagnets, which are excited in contrast or in agreement with the permanent magnet, to form a plurality of selection positions on two fronts along which run the elements to be selected.
The device includes at least one selection lever, one end whereof is arranged laterally facing the needle cylinder at the level of a heel of selection elements accommodated in the grooves of the needle cylinder below the selectors or sub-needles. The selection lever is movable towards or away from the needle cylinder from a first position, in which its end engages the heel of the selection elements, to a second position in which it does not interfere with said heel. The end of the selection lever has a rising portion which in the first position raises the selection element when the needle cylinder rotates with respect to the selection lever. As an effect of this lifting, the overlying selector is engaged by a lifting cam arranged facing the needle cylinder so that the overlying needle is moved to knit.
For needle selection in a circular knitting machine, a device is disclosed which comprises a plurality of superimposed selecting levers, individually pivoted to a common structure and selectively movable between a position where they do not interfere with the pattern jack butts and a position where they interfere therewith, to urge them toward the needle cylinder. The selective movement is accomplished by means of electromagnets, one for each selecting lever, which are energized in accordance with the machine knitting program and move intermediate, preferably rod-like, drive elements the axial displacement whereof results in a pivotal movement of the respective selecting levers between the cited positions. The engagement of the intermediate elements with the selecting levers is accomplished through geometrical coupling. A minimal force is sufficient for the actuation, so that the size of the electromagnets can be minimized, while a prompt response is ensured.
A needle selection mechanism for knitting machines wherein each selector member has a selection cam portion and a cocking member engaging portion which cocking member is constituted by a jack butt adapted to be selected by the selector member and in turn cock the selector member whereby the latter, when held by an electromagnetic misses the following selector jack having a butt at the same level, and when released thereby engages said following selector jack.
A hook selection device for a weaving loom dobby head where the dobby includes a bottom board carrying hooks and an upper part for supporting the selection device. The upper part moves relative to the bottom board and includes rigid heald shafts provided with a catch corresponding to each hook on the bottom board. The position of each catch relative to a corresponding hook being controlled by an electromagnetic device having a coil. Each rigid heald shaft has a portion made of magnetic material and is mounted on the upper part so as to pivot about a pin. The selection device creates a permanent magnetic field in a region of the selection device having the heald shaft. The coil and permanent magnetic field drive the heald shaft to pivot either into a first position to permit entrainment of a catch and corresponding hook and a second position which does not permit entrainment.
