Military Uses of True-Lock Fasteners


Todays armored vehicles are a direct result of over fifty years of evolutionary development.

The lessons learned in battle have been combined with modern technology to produce the worldis finest armored fighting machines, as clearly demonstrated in the Gulf War. The armament system on the M1 Abrams is a marvel of electronics that gives it unparalleled targeting accuracy and firing capability. The powerful engines produce impressive speeds and the protective armor can withstand considerable pounding from the enemy. The design of the track and suspension have made the modern tank a truly all terrain vehicle capable of on and offroad travel. With all of the numerous developments that have taken place over time, there is still one area that has never been improved.

There remains one problem that, until now, has never been solved.


Introducing TRUE-LOCK

The solution is a lock that will prevent wedge bolts from rotating loose. This is the patented TRUE- LOCK safety fastening system:

  • active locking system that does not rely on the tightness of the bolt
  • does nor require or allow overtorquing
  • simple to install and remove
  • reusable.

The system consists of a retaining plate, a snap ring, and grooved wedge bolts. The system can be retrofitted to existing tracks or included into new vehicle designs. The wedge bolts have been adapted from those currently being used, except that a groove has been machined into each point to fit the thickness and size of the snap ring.

Each bolt is installed and tightened as normal. The retaining plate is then slipped over the head of the wedge bolt. Cutouts in the plate are similar to a socket wrench and match the hex head on the bolt. These cutouts are rotated slightly to allow for a high degree of adjustment and the retainer can even be flipped over to allow for a better fit. The retainer has two shoulders which fit into the recess on the top of the end connector. The retaining plate is then secured with the snap ring. The snap ring locks the retainer into the recess of the end connector and the retainer locks the wedge  olt and prevents it from rotating loose. The time spent on constantly retightening the wedge bolts has been eliminated and the danger of a track related accident due to a lost end connector has been greatly reduced. Routine inspections of the track are still necessary, but they are far easier and can be done visually, because if the retainer is in place, the wedge bolt cannot be loose. TRUE LOCK eliminates the retightening of bolts.

TRUE LOCK has been successfully tested on M1 tanks by the U.S. Army in Boise, Idaho and by the Marine Corps at Twenty-nine Palms, California. The test results have shown that tanks with the TRUE LOCK system installed have not had any wedge bolts come loose and has significantly increased the life of the track.

The system also works extremely well on applications where the nut is used to secure an adjustable part, such as the axles and wheel bearings on vehicles like the Humvee.




The performance of a tank in battle is dependent upon mobility.

A track failure can bring the modern armored vehicle to a grinding halt and place the crew at risk. The track is held on by end connectors, which are secured by wedges and fastened with bolts. Wedge bolts are subjected to tremendous forces throughout the full range of motion of the track. These forces are acting to loosen the wedge bolts. 

Bolts are systematically tightened during the installation of the track and after 20 miles of travel.

Tank crews are taught to constantly inspect end connectors for loose wedge bolts, which is not a simple task. Missing bolts are easy to notice, loose bolts are not. This system of checks and rechecks, tightening and retightening of wedge bolts is intended to identify a potentially dangerous situation and remedy it before it progresses to the point where an end connector is lost and the track comes apart. All of these procedures, however, are just a treatment for the symptoms. They do nothing to solve the problem, nothing to prevent the bolts from coming loose in the first place.

This is time that, in battle, is far too valuable to risk the lives of the crew by having them outside of the protective armor.

This is time that could be spent performing needed maintenance and maneuvering on the range or training on the armament system.


Supporting Documents

Click here to view supporting documents on True Lock military application.