Abstract The invention relates to an improved inductive transmitter for indicating and measuring linear position changes comprising at least two iron cores each with primary and secondary windings cooperating with an armature of magnetic material, the cores or armature being movable in relation to the transmitter. Both the iron cores and the armature are provided with spaced teeth which are confronting each other so that the magnetic coupling between the windings of the cores will change when the relative position of the armature to the cores is changed. The essential feature of the invention is that the armature teeth cooperating with one core are displaced relative to the armature teeth cooperating with the other core. This provides an improved symmetrical function of the magnetic coupling in each transmitter and the invention also includes some specific embodiments of this arrangement. In one embodiment two iron cores are spaced with their toothed surfaces facing each other thereby forming an airgap in which an armature is disposed. The armature could be in the form of a corrugated strip so that the armature teeth cooperating with one iron core will form the slots cooperating with the other iron core which means that the teeth cooperating with the two iron cores will be exactly 180 degrees displaced in relation to each other.
In an inductive apparatus for indicating mechanical positions and/or measuring linear positional changes, comprising two transmitter means, each including primary and secondary windings operatively coupled to an alternating current voltage source and a magnetic core with substantially rectangular cross section, said cores being provided with teeth to form slots for said primary and secondary windings, an armature of magnetic material, which is also provided with spaced teeth facing the teeth of said cores, said armature being displaceable in relation to said transmitters in order to change, upon displacement, the magnetic coupling between the primary and secondary windings of said cores, the improvement wherein armature teeth cooperating with one transmitter core are displaced 180* in relation to armature teeth cooperating with the other transmitter core, each of said transmitters being adapted to produce an alternating current voltage vector of the type: U k1U sin (wt.+ Beta ) wherein Beta is the angular position of the armature in relation to said one transmitter core and varies from 0* to 360* when the armature is displaced one tooth pitch, said two cores being positioned in spaced relationship with their slotted surfaces facing each other so that each core forms the mirror image of the other core, said armature being formed as a corrugated strip, which is disposed in the interspace between said cores, whereby the armature teeth cooperating with one of said transmitter cores will be exactly 180* displaced in relation to the armature teeth cooperating with the other transmitter core.
Claim 2
Dependent Claim
248 words
In an inductive apparatus for indicating mechanical positions and/or measuring linear positional changes, comprising two transmitter means, each including primary and secondary windings operatively coupled to an alternating current voltage source and a magnetic core with substantially rectangular cross section, said cores being provided with teeth to form slots for said primary and secondary windings, an armature of magnetic material, which is also provided with spaced teeth facing the teeth of said cores, said armature being displaceable in relation to said transmitters in order to change, upon displacement, the magnetic coupling between the primary and secondary windings of said cores, the improvement wherein armature teeth cooperating with one transmitter core are displaced 180* in relation to armature teeth cooperating with the other transmitter core, each of said transmitters being adapted to produce an alternating current voltage vector of the type: U k1U sin (wt.+ Beta ) wherein Beta is the angular position of the armature in relation to said one transmitter core and varies from 0* to 360* when the armature is displaced one tooth pitch, said two cores being positioned in spaced relationship with their slotted surfaces facing each other so that each core forms the mirror image of the other core, said armature being formed as a corrugated strip, which is disposed in the interspace between said cores, whereby the armature teeth cooperating with one of said transmitter cores will be exactly 180* displaced in relation to the armature teeth cooperating with the other transmitter core.