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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. This is time that could be spent maneuvering
on the range or training on the armament system.
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 remov
- 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.
Supporting Documents
Letter by Gary Scott Summary of Progress dated August
15, 1996 link to file
Summary :
Mr. Scott states that there is a lot of difference in opinion on whether
there is a problem with wedge bolts coming loose or not. This
difference in opinion has such a wide range because it depends on what
is considered a problem and how far that person is removed from working
with the vehicles. In discussions with maintenance personnel
it turned out that wedge bolts do come loose and that and nothing the
military has to offer can fix that problem. The only way to solve
the problem is to check and retighten each wedge bolt individually. This
consumes large amount of man-hours, which is a problem to the tank
crews and personnel. The True-Lock system can fit this problem
once and for all and reduce track inspection to a visual inspection. That
means if the bolt is in place it is tight and hence reduces maintenance
man-hours and track wear increases mission capabilities and improves
crew safety.
Letter from True-Lock to US Senator Kempthorne dated
August 20, 1996 link to
file
Summary :
This letter explains that the military has two different answers to wedge
bolts coming loose on tracks. The first being that there is no
such problem and the second being that this problem did exist in the
old T-156 track but not on the new T-158 track and if it does then
the maintenance crews are installing the components incorrectly. Testing
conducted by True-Lock with tanks at Gowen Field and with the Marines
at 29 Palms has shown that the True-Lock system solves the issue of
wedge bolts coming loose. It is suggested that the Senator have
a meeting with the people who work with the vehicles to get to the
core if the issue. A number of questions that could be asked
are suggested in the letter as well. This meeting would provide
a good understanding as what is really going on with the tank tracks.
Letter from True-Lock to Col. Chris Cardine dated 10
August 1995 link to file
Summary :
This letter informs Col. Cardine that the True-Lock system was tested
by the Army National Guard in Boise and the Marine Corps at 29 Palms. The
tests prove that the system works and eliminates the need for continual
inspection and re-tightening of wedge bolts. True-Lock has only
received positive feedback by the crews involved in the testing. Below
are two accounts of personnel involved in the testing of the True-Lock
system:
- SFC Kulm, a maintenance supervisor states that those
end connector bolts that had the True-Lock system installed were not
lost, while those end connectors that did not have the True-Lock system
installed were lost.
- MAJ Bishop states that the True-Lock system has
significantly reduced the long-standing problem of loose end connectors.
Letter from MSgt Segura USMC to Leslie Weinstein dated
12 September 1995 link
to file
Summary :
MSgt Segura has seen many items being tested on the M1A1 tank and the
True-Lock system was the most impressive, simple, common sense item
he saw. In his twenty years of tank experience the one problem
he noticed that never was solved was that of missing end connector
bolts. During the field operations the different crew always
requested end connectors bolts and nuts, except the tank that was equipped
with the True-Lock system.
Letter from Sgt. Murphy IDARNG to Leslie Weinstein dated
25 October 1995 link to
file
Summary :
Sgt Murphy states that it takes about two to two and a half hours to
install the True-Lock system on each end connector on the track before
mounting it on the tank. But this time would be more than off-set
by the time savings at the operator level as the system allows for
visual inspection of the end connectors rather than manually testing
each bolt with a socket. The True-Lock system maintains torque
value on bolts, which prevents these from failing, which results in
broken and/or lost bolts. That will ultimately contribute to
a saving in parts.
Letter from SFC Drescher to Col Cardine PM Abrams dated
25 October 1995 link to
file
Summary :
SFC Drescher explains in his letter that he has been involved with tanks
since 1969 and that his tank was chosen to have the True-Lock system
installed and tested. He has not experienced any loosening/loss
of bolts since the initial installation of the system. And while
he visually inspects his track, other crews are out replacing/retightening
wedge bolts, which SFC did not have to do yet. When inspecting
the end connectors with the True-Lock system installed reveals even
wear of the exterior and no wear on inner portions of the end connector. Those
connectors without the system had uneven wear on the exterior and some
wear on the interior. The True-Lock system works and allows SFC
Drescher to spend more time training students and save the Army money. |
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Supporting Documents
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Below is a list of supporting
military documents on the effectiveness of the TRUE-LOCK fastener
system on the M1 Abrams Track T158/T158LL End Connector.
Letter from Brigadier General Philip L.
Bolte, USA Ret. to Colonel Christopher V. Cardine dated 9 January
1998 link
to file
Summary :
US Army Brigadier General Philip Bolte concludes that tank crews
still spend considerable amounts of time checking and tightening
end connectors on tank tracks. He is not convinced
that the problem does not exist/has been solved as senior officers
in the Armor Community state and thus they are not being true to
its Armor soldiers. The National Guard at Gowen Field
has concluded that the True-Lock system on Abrams tanks with T158
track solves the current problem of end connectors loosening. CW3
Lowe and CW3 Medlin stated that end connectors often loosen and
fall off and that crews spend much time on tightening these connectors.
Captain Julian (Maint. Ofcr, 1st ATB) states that a considerable
amount of money is spent in replacing end connectors. CW3
Lowe states that there have been several accidents and subsequently
damage to tanks due to loose/lost end connectors.
Letter from True-Lock to Colonel Christopher V.
Cardine dated 26 February 1998 link
to file
Summary :
True-Lock offers the government to fabricate
and design their own safety retention system for the grille doors
on the M1 Tank. That system will solve the deficiency of
currently used J hooks, that do not have the needed toughness to
withstand the pressure and extreme temperatures of the exhaust
system. This has been shown in tests at Gowen Field and evaluated
by PM Abrams.
Fax to Leslie Weinstein from Brigadier General
Phil Bolte dated April 2, 1998 link
to file
Summary :
Fax includes statistics that show the total l use and cost of bolts,
wedges and kits used in six years by 262 M1A1 tanks over 1, 064,713
miles of use. Furthermore Brigadier General Bolte states
that troops during Desert Storm were told not to get out of their
tanks due to unexploded munitions and mines on the ground and he
furthermore wonders what crews should do if they lost end connectors,
which has nothing to do with cost-effectiveness.
Fax to Leslie Weinstein from PM Abrams Tank System
dated June 10, 1998 link
to file
Summary :
This fax includes the test strategy for the True-Lock system on the
M1 tank, which includes a comparison test (i.e. durability test
until track failure) between the current systems used on the tanks
and the True-Lock system
Letter from True-Lock to Tom Kraskiewicz PM Abrams
dated 22 June 1998 link to
file
Summary :
True-Lock has permission to test its system on the M1 Abrams and
is furthermore allowed to be actively involved in the preparation
for the tests to be conducted in December 1998. True-Lock
wants to shift the focus of the test from “does the True-Lock system
work” to “how will the True-Lock system allow dramatic change in
how the vehicle is operated and maintained”. True-Lock is
convinced that their system will reduce the time spend on checking
and maintaining the tank track, reduce track wear and costs normally
used to replace lost parts. This will enhance safety and
reliability and mission effectiveness. Other tests could
be conducted on the locking systems for the center guide bolts
on the track and the exhaust grill doors for which parts have been
supplied that were tested at Gowen Field.
Letter from True-Lock to Lt. Col. John Bryant
MARCORSYSCOM dated 23 June 1998 link
to file
Summary :
This letter provides Lt. Col. Bryant with an update on the
upcoming test on the T158 track end connectors that will commence
in December of 98. True-Lock stresses that they want to conduct
as demanding and thorough a test as possible and to shift the focus
from “does the True-Lock system work” to “how will the True-Lock
system allow a dramatic change in how the vehicle is operated and
maintained”. True-Lock is wondering if the Marine’s would like
to conduct a test of their own, even though the Army has already
approved testing of the True-Lock system.
“How does a one dollar bolt stop a seven million
dollar tank?” link
to file
Summary :
Over the past fifty years tanks have evolved dramatically and turned,
in combination with modern technology, into the world’s finest
armored fighting machine. The M1 Abrams truly is that one
superior tank, with one of a kind firing capability and accuracy,
impressive speeds, tough armor, and the design of the track and
suspension give this vehicle all terrain capabilities. All
these improvements have taken place over time, yet there remains
one area that has not been improved and remains a problem to this
day. The track. A failure of the track will render
a tank useless and the crew at risk. The track is held on
by end connectors, which are secured by wedges and fastened with
bolts. The wedge bolts are subject to tremendous forces throughout
the full range of motion of the track. These forces are acting
to loosen the wedge bolts. Tank crews are instructed to constantly
inspect end connectors for loose wedge bolts after twenty miles
of travel. Missing bolts are easily spotted, loose ones are
not and thus this inspection takes a considerable amount of time,
as each bolt must be individually retightened. This procedure
puts the crew in harms way as they spend time outside of the tank. This
procedure treats the symptoms, but does not solve the problem of
the bolts coming loose in the first place. The time it takes
to inspect, repair and maintain the wedge bolts could instead be
used to further train the tank crews. True-Lock has the solution
to this specific problem of wedge bolts coming loose. The
system can be retrofitted to existing tracks or included into new
vehicle designs. The True-Lock system is installed and tightened
as normal as maintenance crews are used to and further retightening
is not required. Routine inspections are still necessary
but are far easier as they can be done visually, because if the
retainer is in place the wedge bolt cannot be loose. 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. These
tests yielded that the bolts do not come loose and that track life
extends. True-Lock can be fitted to any existing nut or bolt
application, from eyeglasses to heavy construction equipment. This
system also works on moveable parts such as axles and wheel bearing
of vehicles and landing gear and engines of planes.
Letter from Headquarters 1st 204th Regiment Armor
to Lou Ashley, HQ AMC dated 27 June 1997 link
to file
Summary :
In this letter SFC Gerard Dresher, who has extensive background as
an armor instructor, states that there is a very real problem with
wedge bolts coming loose on the M1-A1 T158 track and that the True-Lock
system works. SFC Dresher installed the True-Lock system
on his own tank in 1994 and accumulated over 2,500 miles with the
vehicle till 1997 when the track was removed. The track was
not completely worn, hadn’t lost any end connectors and no wedge
bolts had to be retightened in those three years with the True-Lock
system. He goes on to state that the True-Lock system was
tested on the improved T-158 track. Inspection was much easier,
as it only took a visual inspection to see if the True-Lock system
was still in place, as it did not come loose. With the other
system each individual bolt had to be retightened to see if it
was loose or not, which is a very time consuming task. While
other crews checked their tracks this way SFC Dresher was able
to spend far less time doing a visual inspection. Another
benefit of the True-Lock system is reduced wear wedge bolts and
other track components. The end connectors without the True-Lock
system had considerable wear and uneven wear on inner and outer
areas. The True-Lock system is simple and effective and reduces
wear on parts and man-hours required to inspect vehicles. This
is an improvement in safety and combat reliability.
Fax from Capt. Muller US Marine Corps Memorandum
dated 3 July 1997 link
to file
Summary :
Marine Corps Inspector-Instructor Captain Muller states that even
though the T-158 track is an improvement over the older T-156 track,
it still requires considerable number of man-hours to inspect and
maintain the track. The most common problem found is loose
or missing wedge bolts, which secure the end connectors that join
the individual track blocks together. Captain Muller believes
that the True-Lock system has the potential to solve the above
mentioned maintenance concern, as it costs 3-4 man-hours a day
to inspect the track and causes premature wear on the track. This
amounts to about 28 man-hours per drill weekend just used for this
maintenance issue which could be reinvested in training and thus
mission readiness. |
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