Gentex SPH-5 Manual

DUAL VISOR
SPH-5âHELMET ASSEMBLY
Fitting, Operation, and
Maintenance Instructions
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CONTENTS
INTRODUCTION AND GENERAL DESCRIPTION .............. 1
HELMET SIZING ................................ 2
HELMET FITTING AND OPERATION ..................... 3
INSPECTIONS .................................12
CLEANING ...................................14
REPLACEMENT PROCEDURE 1:
ENERGY-ABSORBING LINER AND TPL ...................14
REPLACEMENT PROCEDURE 2: RETENTION ASSEMBLY.........15
REPLACEMENT PROCEDURE 3: EARCUPS AND EARPHONES ......16
REPLACEMENT PROCEDURE 4: MICROPHONE ASSEMBLY .......18
REPLACEMENT PROCEDURE 5: COMMUNICATIONS CORD .......19
REPLACEMENT PROCEDURE 6: DUAL VISOR ASSEMBLY ........21
ILLUSTRATED PARTS BREAKDOWN ....................24
OTHER VISOR STYLES AVAILABLE .....................26

INTRODUCTION AND GENERAL DESCRIPTION
This booklet provides operation and maintenance instructions, as well as an
illustrated parts breakdown (IPB) on page 24, for the GENTEX® SPH-5®Helmet
Assembly (Figure 1).
The SPH-5 is a lightweight helmet assembly providing head protection, noise
reduction, and communication enhancement for helicopter personnel. It consists
of an impact-resistant helmet shell, a polystyrene energy-absorbing liner, a
preformed thermoplastic liner (TPL®) that allows for custom-fitting, a yoke-style
retention assembly (including a chinstrap and a nape strap — both adjustable),
sound-attenuating earcups, a dual visor assembly, and a communications
assembly featuring a boom-mounted microphone and dual earphones. The
helmet is available in four sizes: small, regular, X-large, and XX-large. (Other
visor assembly styles are available and are listed at the end of this booklet.
Contact Gentex Corporation for more information.)
Figure 1. SPH-5 Helmet Assembly
GENTEX®, SPH-5®, and TPL® are registered trademarks of GENTEX Corporation.
1
HELMET
SHELL
BOOM AND
MICROPHONE
EARCUP
ASSEMBLY (2)
RETENTION
ASSEMBLY
DUAL VISOR
ASSEMBLY
ENERGY-ABSORBING
LINER
TPL

HELMET SIZING
Helmet sizing is based on head circumference. (Figure 2 shows how the
crewmember’s head is measured for circumference.) Below are sizing
parameters.
HELMET SIZE MAXIMUM HEAD CIRCUMFERENCE (INCHES)*
Small < 21.5
Regular 21.5 - 22.4
X-Large 22.4 - 23.5
XX-Large > 23.5
•These are rule-of-thumb measurements. At times, the next larger or smaller
size may be required to achieve a satisfactory fit.
Figure 2. Head Circumference for Helmet Sizing
2
TAPE MEASURE

HELMET FITTING AND OPERATION
In this procedure, you will ensure that the helmet is properly fitted to the
crewmember. You will also familiarize the crewmember with operation
procedures, including donning and doffing the helmet (Steps 1 and 8
respectively), adjusting the nape strap (Step 2), fastening and unfastening
the chinstrap (Steps 3 and 7 respectively), operating the visors (Step 4), and
operating the communications system (Step 5).
1. Have the crewmember don the helmet as follows:
CAUTION
Spread the helmet slightly – just enough to allow ease of
donning. Excessive spreading may damage the helmet.
a. Grip the retention
assembly below the
earcups as shown in
Figure 3, view A.
b. Spread the sides of the
helmet slightly and
position the front edge
firmly against the
forehead as shown in
Figure 3, view B.
c. Roll the helmet back and
down onto the head.
Press the helmet firmly
downward with both
hands to ensure that the
helmet is properly seated
on the head and the ears
are surrounded by the
earcups. (The earcups
can be rotated for
optimum fit.)
d. Check the distance
between the eyebrows
and the edge of the
helmet shell; it should be
approximately (but no
more than) 3/4” for
optimum field of view.
(Continued on next page)
3
Figure 3. Donning Helmet
A
B

WARNING
For helmet stability, always tighten the nape strap and the
chinstrap as snugly as possible when wearing the helmet.
Failure to do so may result in injury.
2. Have the crewmember tighten the rear of the retention assembly by
adjusting the hook-and-pile closure and tightening the nape strap
through the adjustment buckle. (See Figure 4.)
Figure 4. Rear of Retention Assembly
3. Have the crewmember fasten the chinstrap as follows:
a. If not already done, insert the snap end of the chinstrap through the
D-ring on the right side (as worn) of the retention assembly and fasten
the snap as shown in Figure 5, view A.
b. Feed the other end of the chinstrap through the D-rings on the left side
of the helmet.
c. Split the D-rings, loop the chin strap end back through inner D-ring, and
pull the chin strap through both D-rings as shown in Figure 5, view B.
d. Tighten the chinstrap to the desired tension. Once the desired tension
is achieved, the chinstrap can be fastened and unfastened via the snap.
Figure 5. Fastening and Adjusting Chinstrap
4
HOOK-AND-PILE CLOSURE
NAPE STRAP
ADJUSTMENT BUCKLE
AB

4. Have the crewmember lower and raise the visors as follows (to test
operation and clearance):
NOTE
Visor knobs can be moved to either side of the visor housing
depending on crewmember preference. See Page 23 for
instructions.
Inner Visor
a. Unlock the visor by
pushing the actuator
knob downward as
shown in Figure 6,
view A.
b. While holding the knob
down, raise or lower
the visor by sliding the
knob along the track.
c. Release the actuator
knob in any of the
visor lock positions.
Outer Visor
a. Unlock the outer
visor by turning the
center lock knob
counterclockwise as
shown in Figure 6,
view B.
b. Rotate the visor by
sliding the knob along
the housing slot.
c. Lock the visor by
turning the knob
clockwise.
(Continued on next page)
5
Figure 6. Raising and Lowering Visors
A
B

CAUTION
In Step 5, be sure to loosen the knurled nut on the swivel
assembly before you rotate the boom assembly. Any attempt
to rotate the boom assembly without loosening the knurled nut
can cause the mounting hole in the helmet shell to become
rounded; consequently, the boom assembly will not be held in
place.
5. Referring to Figure 7, have the operator operate and adjust the
communications system as follows:
a. Loosen the boom swivel assembly by rotating the knurled nut
counterclockwise until the boom is free to move.
b. Rotate the boom up or down as needed.
c. Slide the boom backward or forward as needed.
d. Tighten the swivel by rotating the knurled nut clockwise.
e. Adjust the front of the boom as needed.
f. Loosen the knurled screw on the microphone, and adjust the
microphone as needed. Tighten the screw.
Figure 7. Communications System Points of Operation
6
CONNECTOR
MICROPHONE
PLUG
KNURLED NUT ON
BOOM SWIVEL ASSEMBLY
KNURLED SCREW
ON MICROPHONE
MICROPHONE
FRONT OF BOOM

6. Evaluate the fit according to the following criteria:
a. The earcups should surround the ears completely.
b. The earseals should be compressed to the greatest degree possible
without discomfort.
c. The overall fit should be comfortable; no hot spots or pressure points
should exist.
NOTE
After evaluating the fit, you will unfasten the chinstrap and doff
the helmet as instructed in Steps 7 and 8. If the helmet fulfills
all of the criteria listed in Step 6, mark and store the helmet as
required. If the earcups do not surround the ears completely,
refer to “Adjustment #1: Earcup Centering.” If the earseals are
not sufficiently compressed, refer to “Adjustment #2: Earseal
Compression.” If the overall fit is too tight or too loose, or hot
spots or pressure points exist, refer to “Adjustment #3: TPL
Custom-Fitting.”
7. Have the crewmember unfasten the chinstrap by unsnapping the strap and
disengaging the strap through the right-hand (as worn) D-ring.
8. Have the crewmember doff the helmet as follows:
CAUTION
Spread the helmet slightly – just enough to allow ease of
doffing. Excessive spreading may damage the helmet.
a. Hook the thumbs in the earcups and spread the helmet at the earcup
area.
b. Roll the helmet upward and rearward as shown in Figure 8.
Figure 8. Doffing Helmet
7

Adjustment #1: Earcup Centering
1. If the ears are not centered within the earcups, rotate the earcups within the
retention assembly. Don the helmet, tighten the chinstrap, and recheck the
earcup centering.
2. If the ears are not centered within the earcups after the earcups have been
rotated, unfasten the chinstrap, doff the helmet, and remove the TPL as in
Replacement Procedure 1, Step 1 (Page 13). Have the crewmember don
the helmet and hold it so that the edge of the helmet is approximately 3/4"
above the eyebrows. With the helmet in this position, check the location of
the earcups. If the earcups now completely surround the ears, this indicates
a need for TPL custom-fitting. Have the crewmember doff the helmet.
Perform the TPL Custom Fitting Procedure. This should result in a proper
fit of the helmet and the earcups.
3. If the ears are not centered in the earcups after the TPL has been removed,
or you must raise or lower the helmet to achieve proper centering, you will
have to adjust the retention straps upward or downward. To obtain access
to these straps, you must remove the energy-absorbing liner and at least one
earcup. Follow these steps:
a. Remove either earcup from the retention assembly as in Replacement
Procedure 3, Steps 2 and 3 (Page 16).
b. Remove the energy-absorbing liner as in Replacement Procedure 1,
Steps 3 and 4 (Page 14).
c. Adjust the retention strap
holes upward or downward as
necessary. The front and
center straps allow for upward
or downward adjustment; the
rear straps allow for forward
or rearward adjustment. (See
Figure 9.) Remove the
attachment hardware. Apply
one or two drops of white
Weldwood glue #281 or
equivalent to the first two
threads of each screw and
reinstall the hardware in the
selected holes as needed.
d. Reinstall the energy-
absorbing liner as in
Replacement Procedure 1,
Step 5 (Page 14).
e. Reinstall the earcups as in Replacement Procedure 3, Steps 10 -11
(Page 17).
8
Figure 9. Retention Straps
FRONT STRAPS
CENTER
STRAPS
REAR STRAPS