DISC-LOCK Locking Washers for Rod Monuments

• The only structural vibration-proof self-tightening locking device on any survey monument
• Keeps connections between point, rod sections, and threaded caps "locked" during and after installation procedures requiring severe vibration impacting of rotating rod monuments.

The DISC-LOCK principle consists of two (2) washer-shaped pieces that have inclined cams on one side and ridges on the other.  The lead angle of the cam surface is greater than the pitch of the threads and therefore prevents rotation in a direction to allow vibration to loosen connections in severe driving conditions.  When sections are tightened the seizing ridges grip; if incorrect rotation begins, cam angles force parts together to actually increase preload, and further tighten the connection.  DISC-LOCK is also used with the Berntsen Top Security caps... an ideal way to cap rods located inside Berntsen access covers.