Abstract: There is provided a position control drive system having first and second drive units linked together and travelling on parallel running rails. A passive unit riding on a third parallel running rail is pivotally linked to one of the drive units. The pivoting link allows movement of the drive units longitudinally along the rails, but prevents movement in other directions. The pivot compensates for positional differences between the electronic positional control of the drive units and the mechanical linkage preventing the inefficiency in the electronic system, stresses in the mechanical system and, in severe cases, binding of the drive units to the rails.

Abstract: There is provided a position control drive system having first and second drive units linked together and travelling on parallel running rails. A passive unit riding on a third parallel running rail is pivotally linked to one of the drive units. The pivoting link allows movement of the drive units longitudinally along the rails, but prevents movement in other directions. The pivot compensates for positional differences between the electronic positional control of the drive units and the mechanical linkage preventing the inefficiency in the electronic system, stresses in the mechanical system and, in severe cases, binding of the drive units to the rails.

Abstract: The circuit board repair and rework apparatus comprises: a camera; a device for positioning a circuit board in a predetermined location beneath the camera; a computer including a CPU and memory; electrical circuitry coupled between the camera and the computer for digitizing the camera image and supplying the digitized representation of the camera image to the computer; a visual display coupled to the computer; the memory storing "GERBER" data related to a plot or layout of the circuit board positioned beneath the camera; electro mechanical structure coupled to the computer for positioning the camera at a desired position over the circuit board; electro mechanical structure for focusing the camera on the circuit board; and, input devices and circuitry to the computer for controlling the position of the camera and for causing an overlay on the visual display between a plot of the digitized camera image of the circuit board and the plot of the circuit board obtained from the "GERBER" data.