Convergence adjustment arrangement using magnetic tabs with differential

Abstract

A convergence correction arrangement for a television display system using a deflection yoke mounted coaxially upon the neck of a kinescope includes first and second magnetically permeable tabs contiguous with the beam entrance end of the yoke. The tabs are located on opposite sides of the axis and a fixed separation is maintained between them. A first track constrains the tabs against tangential motion relative to the axis while permitting radial motion. A rotary drive arrangement suited to being engaged by a yoke adjustment machine includes a second track having radial and tangentially-directed components. The second track engages the tabs whereby roatary motion of the rotary drive arrangement drives the convergence-adjusting tabs radially and provides differential motion of the tabs relative to the axis for convergence control.