Drill Pressure Foot
Original Publication Date: 1984-Nov-01
Included in the Prior Art Database: 2005-Feb-05
Suspended, populated circuit boards of different thicknesses can be accurately and reliably drilled by using an evacuated, floating pressure foot on the drill. Referring to the figure, a vertically movable drill spindle 1, having a turbine 2 and drill 3 therein, supports a sleeve 4. The sleeve carries guide rods 5, on which a housing 6 can move vertically relative to sleeve 4. An air bearing is provided between the inner diameter of the housing and mating outer diameter of the sleeve to permit friction-free movement. Housing 6 carries a pair of opposed air cylinders 7, whose piston rods 8 are each attached to a reciprocable slide 9. Each slide is formed at its inner end as half a pressure foot 10. At its outer end, each slide carries a cam 11 that actuates either one of a pair of limit switches 12 as the slide is moved.