Marker for Indicating Correct Tightening of Screws
Original Publication Date: 1984-Oct-01
Included in the Prior Art Database: 2005-Feb-06
A hand held tool has a socket and an air driver motor that drives the socket to tighten a screw to a preset torque. When the preset torque has been reached, a port is opened to admit pressurized air to operate a screw marking mechanism. The socket is connected to the motor by means of a hollow drive shaft. Inside the drive shaft is located a tube which contains a commercially available screw marking dye and which holds a wick for applying the dye. The wick extends forwardly into the socket. The dye tube and wick fit inside the drive shaft and form a piston for driving the wick forward against a screw. A spring that is located between the dye tube and the drive shaft returns the dye tube to its retracted position when not activated.