Anvis Kevlar Helmet Mount Type III (AKHM III) - Wilcox-Res

Anvis Kevlar Helmet Mount Type III (AKHM III)
The AKHM III was designed to be a very rugged product with a number of features not seen on any
similar products. Its purpose if to mount and power the AN/AVS-6(v)1, AN/AVS-6(v)3, AN/AVS-9,
F4949, etc. ANVIS night vision goggles onto the PASGT, ACH, MICH and other Kevlar helmets.
The AKHM III is a self contained powered mount that functions much like the Low Profile Battery Pack.
It uses two CR123 3.0 VDC batteries. One battery provides power to the ANVIS NVGs and other
features while the other battery monitors the main power battery and when the main power battery voltage
drops below 2.4 VDC a small red LED starts to blink warning the operator that the battery voltage is low
and to switch to the other onboard battery.
The AKHM contains a dual 35mW 880 nm IREDs to illuminate the area in front of the operator when
needed. It also contains a 6000 mcd warm white LED pointing 90 degrees downward from the NVGs
used to illuminate clipboards, maps, and other items when the operator is looking down below his NVGs.
AKHM III Component Identification & Functions
- The CR123 Battery Caps retain the batteries used to power this device. The caps also serve to seal the
battery compartments from environmental factors and provide a conductive path from the battery’s
positive terminal to the AKHM III’s electronics.
- The Main Power Switch conducts electrical power from the left or right battery to the AKHM III’s
electronics. When the switch is moved to the right the right side battery compartment supplies main
power, while the left side battery supplies power to the main power voltage monitoring circuit. When the
switch is moved to the left, the left side battery provides main power to the AKHM III’s electronics, while
the right side battery powers the monitoring circuit.
- The InfraRed Illuminator switch supplies power to the dual IREDs. This switch has to be deliberately
moved forward to supply power. The switch’s actuator is positioned against the battery compartment to
reduce the possibility of accidentally powering the IREDs. Turning IRED power off is just a matter of
hitting the switch back.
- The Warm White LED switch is used to power the downward pointing bright warm white LED. This
switch is located so that the possibility of accidental actuation of the switch is reduced. This switch is a
momentary contact pushbutton switch, which means you have to keep holding the pushbutton in to keep
the white LED on.
- The Lock-Release Button enables the ANVIS NVGs to be rotated up from the down (powered) and lock
position or rotated down from the up (stowed) and locked position. This button is a mechanical spring
loaded pushbutton.
- The Vertical Adjustment Knob is used to raise and lower the installed ANVIS NVGs so that the
eyepieces can be properly aligned vertically in front of the operator’s eyes.
- The Dual IREDs provide Infrared illumination in front of the operator to aid in seeing in very low
ambient light conditions or when needing to see greater detail.
- The Keeper Release is used to unlock the AKHM III from the Keeper (ACH front Bracket) When the
Keeper Release is pushed in the mechanism is unlocked allowing the AKHM III to be removed from the
helmet. When locked in place, the Keeper release should be fully extended.
- The Blinking Red LED warns the operator that the Main Power Battery voltage has dropped below 2.4
volts. This warning gives the operator the time to change the battery or switch to the other side’s battery
for main power.
- The purpose of the Warm White LED Illuminator is to temporarily provide natural light for reading
clipboards, maps, and other items when the operator is looking down below his NVGs. Care must be
taken as to where this illuminator is used as it is bright and can be seen with the unaided eye.
AKHM III Battery Installation
First, ensure that the Main Power Switch is in the Center – Off position.
Unscrew the two battery caps and install the CR123 batteries as shown here:
Install the battery caps and tighten until snug.
NOTE: To prevent corrosion, which may lead to possible interruption of main
power, clean and coat the battery cap threads and battery compartment threads
with a Q-tip dipped in CLP or other protecting light oil every time you change
batteries.
WARNING: Never store the AKHM III for long periods of time with the
batteries installed. Doing so may cause damage to the AKHM III if the
batteries leak. Always remove the batteries when storing the AKHM III.
Preparing the Kevlar Helmet
Remove the backing from the adhesive backed pile Velcro as shown here:
Install the pile Velcro on the back of the helmet as shown below.
Install the second adhesive backed pile Velcro on the back of the Helmet.
Attach one or two of the counterweights as needed for balancing the AKHM III ANVIS NVG’s weight
NOTE: The Counterweights provided can be opened and weights removed to vary the weight attached to
the helmet. Simply pull back the Velcroed end of the counterweight and add or remove weights as
needed.
NOTE: Counterweights are used to reduce neck strain and to limit the
helmet rotating forward from the weight of the ANVIS NVGs and the
AKHM III. More information on this subject can be reviewed in the
document: Appendix A.pdf, which covers the study done at Fort Rucker.
The AKHM III Kit comes with a new MATCHED ACH/MICH front bracket. If the AKHM II does not
work with your current ACH front bracket, replace it with the one supplied with your AKHM III.
AKHM III Attachment to the Helmet
Insert the top edge of the AKHM III under the Keeper on the helmet mount bracket…
… and rotate downward…
...until the latch engages.
Pull the Keeper release outward to ensure it is in the locked position. Check mount to ensure that it is
secured to the helmet mount bracket.
To remove the AKHM III from the helmet, push the Keeper Release inward….
…then pull the bottom of the AKHM III away from the Keeper.
ANVIS NVG use with the AKHM III
Once the operator has his helmet properly fitted and adjusted with the AKHM III attached they can then
don the ANVIS NVGs for nighttime ground operations.
Make sure that the AKHM III’s Main Power Switch is in the center / Off position.
Orienting the NVGs as pictured below and using both hands, slide the ball and plunger assembly of the
fore-and-aft assembly into the channels of the AKHM III until they lock in place.
In a low ambient light environment, remove any lens caps and turn the AKHM III’s Main Power Switch
to the Left….
…or right to power the goggles.
Once the goggles are powered you will see green images viewed thru the eyepieces. You first want to
orient the eyepieces properly in front of your eyes to obtain the optimal sight picture defined
below.
To do this you need to adjust the following AKHM III and ANVIS NVGs components:
- The vertical adjustment, which raises or lowers the NVG’s eyepieces in front of your eyes. To raise the
NVGs rotate the Vertical Adjustment Knob as shown here:
To lower the NVGs rotate the Vertical Adjustment Knob as depicted below:
Once the eyepieces are aligned vertically you want to set the eye span by moving the interpupillary
adjustment knobs so that the monocular assemblies move inward….
…or move them outward until the eyepieces are aligned horizontally in front of your ayes to obtain
optimal sight picture.
Next move the fore-and-aft adjustment knob on the ANVIS Position and Adjustment Shelf away from
your eyes if the eyepieces are to close…
…or closer to your eyes to get the optimal sight picture.
Sometimes to attain the correct sight picture you need to tilt the monocular assemblies so the eyepieces
tilt up by moving the tilt adjustment lever up…
..or tilt down by moving the tilt adjustment level down as seen here.
Once the optimum positioning of the eyepieces have been achieved, rotate the eyepieces
one at a time so that tube black spots or scintillations can be seen clearly. Then adjust the
objective lens for distance so that what you want to see is in focus as a crisp image.
Now that Optimum Sight Picture is reached, you can use your ANVIS NVGs for ground operations.
At some point you may need additional illumination than what is available from your environment. The
AKHM III provides you with that illumination using dual IREDs. To power the Dual IREDs, move the
IRED Power Switch forward.
WARNING: The IRED Illumination is invisible to the unaided eye, but can be seen by
others using night vision equipment for some distance. Use this feature only when needed.
You may have the need to view maps, charts, clipboards, etc held below your ANVIS NVGs. The
AKHM III has the ability to illuminate the area below your NVGs with a natural white light, as seen here:
This is accomplished by pressing the small square silver and black pushbutton switch located below the
left battery housing.
The operator can move the ANVIS NVGs out of their way, if they will not be needed for awhile. This is
done by depressing the Lock Release Button on the AKHM III as seen here using a thumb.
Once the Lock release Button is depressed, the ANVIS NVGs can be swing up and back as seen here:
The ANVIS NVGs will remain stowed and locked in the up position until the lock release button is
depressed again. While in the stowed position power is removed from the ANVIS NVGs but remains
available to the AKHM III electronics until the Main Power Switch is moved to the center / Off position.
The AKHM III and ANVIS NVGs can be used without the helmet, much like a set of binoculars as seen
here:
While detached from the helmet the AKHM III and ANVIS NVGs can be separated after placing the
Main Power Switch to the center / Off position.. This is accomplished by depressing the lock release
button and moving the AKHM III forward halfway between the down and lock and up and locked
positions.
Then, grasp the AKHM III in one hand and the ANVIS NVGs in the other hand and pull them apart.
Sometimes you may have to exert a twisting motion on the AKHM III to off seat the ball and plunger
mechanism for them to separate.
When done using the AKHM III, store it in the nylon carrying case. If the AKHM III will not be needed
for a day or more, remove the two CR123 batteries and store in the AKHM III storage case seen below.