Velocity Measuring Technique
Original Publication Date: 1984-Aug-01
Included in the Prior Art Database: 2005-Feb-04
A print hammer mechanism comprises an electromagnetic operator having core 10 with pole 11 and winding 12, pivoted armature 13, push rod 14 and pivoted hammer element 15. The hammer mechanism is operated by energizing winding 12, causing armature 13 to be rotated until it seals against the face of pole 11, whereupon push rod 14 and hammer element 15 continue in motion at relatively constant velocity until the hammer element 15 impacts a platen 16. The velocity measurement technique comprises the steps of detecting the position of the hammer element 15 at or about seal time of the armature 13 and the position of the hammer element 15 just prior to the hammer impacting the platen 16. As seen in the figure, optical sensor 17A detects hammer displacement at or near the time armature seals against pole 11.