Flip-up helmet mount for night vision goggle

A flip-up helmet mount for a night vision goggle includes a plurality of nested relatively movable brackets, the first of which is secured to a user's helmet. A second bracket pivots relative to the first to provide flip-up motion for the night vision goggle, and a third of the nested brackets is pivotal on the second bracket to provide a tilt angle adjustment for the night vision viewer. In order to both save battery power, and to prevent the user from inadvertently revealing his position by forgetting to turn off the night vision viewer before flipping it up, the support structure includes a magnetic flux source cooperable with a magnetically-responsive switch of the night vision viewer to maintain the viewer turned on only when the viewer is in its use position. When the viewer is flipped toward its upward position, the magnetic flux source is responsive to a combination of gravitational force and centrifugal force to move away from the magnetically-responsive switch device and effect turning off of the viewer. Because the viewer remains mounted on the flip-up mount during this series of events allowing the user an unobstructed natural view of the environment, the viewer is immediately available to be flipped downwardly to its use position to be placed back into operation. The gravitationally-responsive magnetic flux source moves back into association with the magnetically-responsive switch when the viewer is returned to its use position.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to night vision devices. More particularly, 
the present invention relates to a flip-up helmet mount for a night vision 
goggle of the type which removably and relatively movably attaches to a 
helmet worn by a user of the device. The flip-up mount secures to the 
helmet to thereby support the night vision goggle in front of the user's 
eyes. As thus supported, the night vision device may be used by the wearer 
of the helmet to view a night scene while the user's hands remain free. 
Also, the helmet mount is provided with a device which is responsive to a 
combination of gravity and a particular movement of a portion of the 
helmet mount during flipping up of the goggle to automatically turn off 
the night vision goggle. 
2. Related Technology 
Conventional night vision devices are known which removably attach to a 
support structure secured to a helmet or face mask. These conventional 
night vision devices are relatively movable by manipulation of the support 
structure to align at least one eye piece of the night vision device with 
at least one eye of the user. Additionally, the support structure and 
night vision device are conventionally provided with cooperating 
structural features which insure that the night vision device is 
electrically deactivated when it is removed from the support structure. 
This conventional feature which turns off the night vision device when it 
is removed from the support structure prevents the battery pack of the 
device from being inadvertently exhausted by leaving the night vision 
device on when it is not in use on the support structure. 
A conventional night vision device which includes features turning off, or 
removing electrical power supply to, the night vision device when the 
latter is moved to a flipped-up position is seen in U.S. Pat. No. 
4,449,787, issued 22 May 1984, to James H. Burbo, et al. The teaching of 
the Burbo patent is believed to include the provision of a pair of 
recesses on a first part of the support structure attached to a helmet. A 
second part of the support structure is secured to the night vision device 
and includes a pair of pins receivable into the pair of recesses to 
pivotally attach and support the night vision device. Electrical contact 
between the night vision device and its battery pack is made through the 
engagement of the two parts of the support structure only when the night 
vision device is pivoted to its use position. Thus, when the night vision 
device is pivoted upwardly to allow the user unobstructed vision, power 
supply to the night vision device is interrupted. Thus the available power 
is conserved, and the night vision device is not inadvertently left on 
when not in use. 
However, the support structure and electrical power interruption features 
of the Burbo device necessarily result in conduction of electrical power 
to the night vision device by way of electrical contacts which are 
exposed. In effect, these exposed contacts are switch contacts because 
they close and open in response to the pivotal movement of the night 
vision device between its use and flipped-up positions. As a first 
consideration, such exposed electrical switch contacts are highly subject 
to damage which can interfere with the conduction of electrical power to 
the night vision device. Secondly, deterioration of the electrical switch 
contacts can result from environmental factors. That is, environmental 
factors may cause corrosion, oxidation, and other deterioration of such 
exposed electrical contacts. These deteriorations of the electrical 
contacts may includes such undesirable effects as pitting, the formation 
of nonconductive oxide coatings, the introduction of environmental dust 
and dirt into the contact interface, and the formation of other films or 
coatings on the exposed contacts. Of course, all of these environmental 
effects are detrimental to the reliable conduction of electrical power to 
the night vision device. The result is that such exposed electrical 
contacts switch contacts compromise the service reliability of the night 
vision device, and cause the device to be frail instead of rugged and able 
to withstand the handling to which such devices are subjected in their use 
environment. 
Another conventional night vision device is known in accord with U.S. Pat. 
No. 4,672,194, issued 9 Jun. 1987, to William A. Kastendieck, et al. This 
Kastendieck patent is believed to teach a night vision device which 
includes a head gear, and a night vision goggle. The goggle includes a 
power supply circuit having a magnetically-responsive switch in series 
with a bi-stable latching relay controlling power supply to the image 
intensifier tube of the goggle. This magnetically-responsive switch is 
arranged to remain closed, and to keep the power supply relay closed, so 
long as the switch is subjected to a sufficient magnetic flux. The head 
gear for the night vision device includes a permanent magnet disposed so 
that it is close to the magnetically-responsive switch when the goggle is 
on the head gear. When the goggle is removed from the head gear, the 
magnetically-responsive switch is moved away from the permanent magnet so 
that the switch opens, an electrical pulse moves the bi-stable relay to an 
open condition, and electrical power to the night vision goggle is 
interrupted. Thus, the goggle is prevented from inadvertently being left 
on when it is removed from the head gear and is not in use. Also, it is 
recognized that inadvertently leaving the night vision goggle on when it 
is not in use can attract the attention of hostile personnel to the 
phosphor yellow/green light emitted from the eyepieces of the goggle. 
However, the night vision device according to the Kastendieck patent does 
not provide for the night vision goggle to be pivoted to a flipped-up 
position while yet supported on the head gear. In order to obtain an 
unobstructed view with the unaided eyes, a user of the Kastendieck device 
must remove the night vision goggle from its position on the head gear in 
front of the user's eyes. 
Another factor to be considered with night vision devices like those taught 
by Burbo and Kastendieck is the severe use environment in which the 
devices may be used, along with the high reliability required from the 
devices in these severe use environments. The use environments for night 
vision devices may include police use or combat conditions in which heat, 
cold, moisture, dust, dirt, bumping, impact, and rough handling of the 
night vision devices by the users are common. Yet, despite these severe 
use conditions, the reliability of the night vision devices should be very 
high. In other words, the devices should be rugged in order to function 
reliably in such environmental conditions and after such rough handling. 
Also, the operative mechanisms should be simple, rugged, straight forward, 
and direct acting in their principles of operation, while still 
accomplishing the desired operational aspects for the devices. The 
environmental factors of moisture, dust, and dirt must be sealed out of 
the operating mechanism, or allowances made for proper operation of the 
devices despite such environmental contaminants in the devices. In view of 
these factors, the frail devices like that taught by Burbo fall far short 
of the operational robustness required for night vision devices. The 
device taught by Kastendieck is deficient in its operational aspects 
because, among other reasons, it cannot be flipped up to allow the user an 
unobstructed natural view while keeping the user's hands free. 
SUMMARY OF THE INVENTION 
In view of the above, a primary object for the present invention is to 
provide a flip-up helmet mount for a night vision goggle which is strong, 
rugged and reliable, and which includes a device for automatically turning 
off the night vision goggle in response to flipping up of the goggle while 
allowing the user freedom of head movement without unintended interruption 
of the night vision provided by the goggle. 
Another object for the present invention is to provide a flip-up helmet 
mount for a night vision goggle in which the device for automatically 
turning off the goggle when the latter is flipped up is environmentally 
isolated to be free of interference with its operation by moisture, dust, 
and dirt, for example. 
Still another object for the present invention is to provide such a flip-up 
helmet mount for a night vision goggle in which the flip-up hinge 
structure is relatively free moving but also provides a desirable degree 
of pivotal friction so that the goggle does not fall freely in the event 
that the user neglects to fully raise the goggle into its flipped-up 
position. 
Yet another object for the present invention is to provide such a flip-up 
helmet mount for a night vision goggle which is easily and inexpensively 
adapted for use on a variety of helmets. 
Another object for the present invention is to provide a flip-up helmet 
mount for a night vision goggle which mounts to the helmet using a minimum 
of securing structures which are easily and quickly attached and detached 
from the helmet, and yet which is securely and reliably attached to the 
helmet. 
Accordingly, the present invention provides a flip-up helmet mount for a 
night vision goggle having a first bracket which secures to the helmet 
with a broad-based hook-like member engaging the brim of the helmet, and 
defining abutment surfaces engaging the front surface of the helmet, and 
engaging a with a single tension strap member extending to the rear edge 
of the helmet to engage this rear edge with a hook; the first bracket 
defines a transverse boss in which is pivotally and frictionally carried a 
bushing member, the bushing member is drivingly engaged by a second 
bracket member which includes a pair of spaced apart flanges straddling 
the first bracket member, for flip-up movement relative thereto with 
pivoting of the bushing member in the boss, near their forward ends the 
pair of flanges of the second bracket member are joined to one another by 
a web, a third bracket member likewise includes a pair of flanges which 
straddle and lie adjacent to the pair of flanges of the second bracket 
member, the second bracket member pivotally carries the third bracket 
member and also carries a locking member which passes through the bushing 
member and actuate slots in the pair of flanges of the third bracket 
member, this locking member clamps the second and third bracket members 
together in a selected position of tilt relative to the user's helmet, the 
flanges of the third bracket member are also joined to one another by a 
respective web for simultaneous tilting movements and each carries one of 
a pair of forwardly extending guide ways upon which is slidably received a 
carriage member, this carriage member defines a socket into which a tang 
portion of a night vision goggle is receivable, also the carriage member 
carries a magnetic device effective to retain the night vision goggle 
activated, this magnetic device is responsive to gravity and flip-up 
movement of the goggle to turn off the goggle. 
An advantage of the present invention resides in the improved user safety 
resulting from automatically turning off the night vision goggle whenever 
it is flipped to its up position, and thereby extinguishing the 
yellow/green phosphor light emission from the eye pieces of the night 
vision goggle. In this up position of the night vision goggle, the eye 
pieces of the goggle are disposed forwardly of the user and possibly 
toward hostile personnel. Were the night vision goggle left on, its 
yellow/green phosphor light emissions could provide an aiming point for 
these hostile personnel. 
Additionally, in its flipped-up position, the night vision goggle is above 
the user's line of sight. Thus, even if a warning light were provided on 
the exterior of the goggle to indicate to the user that the goggle had 
been left on, this warning light might easily be missed by the user. 
Additionally, such a warning light could possibly give away the user's 
position even when the goggle was in its lowered use position. 
Also, the magnetic device is advantageously sealed from the use environment 
so that moisture, dust, and dirt cannot enter to interfere with the 
operation of this important safety mechanism. 
Still further, the magnetic device has only a single moving part which 
relies upon a combination of gravitational force and centrifugal force 
resulting from the flipping-up movement of the night vision goggle to 
insure positive movement of the magnetic device to turn off the goggle. 
Advantageously, the required combination of gravitational and centrifugal 
forces necessary to effect a turning off of the night vision goggle are 
not likely to occur during wearing and use of the goggle, even it the user 
bows or raises the head to look vertically down or vertically up, 
respectively. 
Another advantage resides in the ease with which the present flip-up helmet 
mount can be attached to a helmet. That is, only a single broad-based hook 
structure need be engaged with the helmet brim with the first bracket 
member engaging the helmet front surface. Next, the tension strap is 
hooked to the helmet rear edge, and drawn tight with an over-center 
buckle. Removal of the flip-up helmet mount from a user's helmet is the 
reverse of the above. 
Finally, an important advantage of the present invention resides in the 
inherently strong, rugged structure implementing the present invention. 
This structure, by its design well withstands the rigors of the severe use 
environment in which such night vision goggles are used commonly. As a 
result, users of the invention benefit from an increased availability of 
the night vision goggles, and decreased risk that their goggles will by 
unusable or have their utility of use compromised by some failure of the 
helmet mount structure used with the goggles.

DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION 
Referring to all of the drawing Figures in conjunction with one another, 
and especially referring first to FIGS. 1, 2, and 10 in conjunction, a 
human operator 10 is shown using a night vision device 12. The operator 10 
wears a helmet 14 carrying a flip-up helmet mount, generally referenced 
with the numeral 16. This flip-up helmet mount 16 includes a first bracket 
member 18 securing to the helmet 14 with a broad-based hook member 20 
(best seen viewing FIG. 10). This hook member includes a pair of laterally 
spaced apart hook portions 22 which are defined at respective ends of a 
cross bar portion 24 of the hook member. These hook portions 22 engage 
under the brim of the helmet 14, as is best seen viewing FIG. 1. This hook 
member 20 also includes a flange portion, generally referenced with the 
numeral 26, which is removably and adjustably secured to the first bracket 
member 18 to attach the hook member 20 thereto. 
The flange portion 26 takes the form of a pair of vertically extending arms 
28 which are spaced laterally apart to abut corresponding mounting 
surfaces 30 of the first bracket member 18. Each one of these pair of arms 
28 defines an upper and a lower one of two vertically spaced pairs of 
holes 32, the respective lower pair of which receives the pair of screws 
34, as seen in FIG. 10. The screws are threadably received by 
corresponding holes (not shown) of the first bracket member 18. Because 
the hook member 20 may be vertically adjusted relative to the first 
bracket member 18 by placing the pair of screws 34 in either the upper or 
lower pair of holes 32, and the hook member 20 secures to the helmet 14 at 
its brim, the first bracket member has an increment of vertical adjustment 
relative to the helmet 14, as is indicated by arrow 36, viewing FIG. 10. 
Viewing FIG. 10 in conjunction with FIGS. 1 and 2, it is seen that the 
first bracket member 18 defines an abutment surface 38 engaging the outer 
front surface of the helmet 14, as is best seen in FIG. 1. At its upper 
extent, the first bracket member includes a pair of upwardly extending 
arms 40 carrying a pair of spaced apart cross bars 42. The cross bars 42 
cooperate with the arms 40 and the remainder of the first bracket member 
18 to define a pair of slots 44. Received through the slots 44 and around 
the cross bars 42 in a self-cinching serpentine path is a web strap 
portion 46 of an elongate strap assembly 47. A free end 48 of the strap 46 
is available above and behind the first bracket member 18 to tighten the 
mounting of the flip-up helmet mount 16 on the helmet 14, as will be 
explained. 
At a rear end 50 of the strap 46, a pawl member 52 is secured to the strap. 
This pawl member 52 receives the end of an elongate rachet tongue member 
54. Spaced along the length of the rachet tongue member 54 is a plurality 
of rachet teeth 57, each of which is engageable with the pawl member 52 to 
selectively alter the length of the strap assembly 47. At the rear of the 
rachet tongue member 54 is secured an over-center buckle assembly, 
referenced with the numeral 56. This bucket 56 carries at its aft end a 
hook portion 58 which engages the helmet 14 at its rear edge, as is seen 
in FIG. 2. 
Returning to a consideration of FIGS. 1 and 2, it is seen that the first 
bracket member 18 defines a transverse boss 60 having a transverse stepped 
through bore 61 therein (best seen in FIGS. 3, 4 and 7). This stepped 
through bore 61 includes a smaller diameter center bore portion 61a, and 
larger diameter end bore portions 61b. A bushing member 62 is 
non-rotationally received in the center bore portion 61a. Rotationally 
received in the bushing member 62 is a cylindrical journal member 63 
having a through bore 64. About the journal member and within each of the 
bore portions 61b is received first a pair of elastomeric O-ring members 
65, then a felt washer 66, and finally a Delrin washer 67. The sizing of 
the bore portion 61b, journal member 63, and O-rings 65 is such that the 
latter are radially distorted to frictionally engage between the boss 60 
and journal member 63. The Delrin washers 67 serve as shield washers to 
exclude large dust particles from the bore 61, while the felt washers 66 
exclude five environmental dust particles. Consequently, the O-ring 
members 65 provide a smooth frictionally-controlled pivotal motion of 
journal member 63 in the bore 61, and a smooth controlled flip-up motion 
for the night vision device 12. That is, the journal member 63 includes an 
axially projecting interrupted key 68 at each end. As will be seen, the 
night vision device 12 is coupled with the journal member 63 in such a way 
as to be restrained from a pivotal free fall toward its use position 
should the operation 10 not detent the viewer in its flipped-up position. 
Coupled with and carried by the journal member 63 is a second bracket 
member 72. This bracket member 72 includes a pair of spaced apart flange 
portions 74, which are coupled together by a transverse web portion 76. At 
their proximal ends, the flange portions 74 each define an inwardly 
extending boss portion 78 (seen in FIG. 1). These boss portions 78 each 
define a key way 80 (seen in FIG. 7) and one of a pair of transversely 
aligned bores 2. One of the bosses 78 also defines an outwardly disposed 
slot 84 traversing the respective bore 82 (as is best seen in FIG. 7 shown 
in dashed lines). The bosses 78 of the second bracket member 72 are 
aligned with the journal member 63, so that the keys 68 are received into 
the key ways 80. Received through the bores 82 of the second bracket 
member and through the aligned bore 64 of the journal member 63 is a clamp 
pin 85. This clamp pin 85 includes a central cylindrical section 86 
separating opposite head 87 and threaded end 88 sections. Adjacent the 
head section 87, the clamp pin 85 carries a cross pin 92 which is received 
in the slot 84. Consequently, the clamp pin is non-rotational in the bores 
64, 82, but has a limited degree of axial freedom of movement in these 
bores. 
At the distal end of the second bracket member 72, each of the flanges 74 
defines a respective ear portion 94 (seen in FIGS. 3 and 4) having a 
threaded bore 96. Threadably received into the bores 96 are a pair of 
shoulder screws 98. The shoulder screws 98 pivotally carry a third bracket 
member 100. This third bracket member 100 also includes a pair of spaced 
apart flange portions 102, 104 which straddle and are adjacent to the 
flanges 74 of the second bracket member 72. That is, each of the flange 
portions 102, 104 defines a respective through bore 106 pivotally 
receiving one of the shoulder screws 98. At the clamp pin 85, the flanges 
102,104 each define an arcuate slot 108, which are of sufficient dimension 
to pass the cross pin 92. The clamp pin 85 is passed into the bores 64, 82 
by first inserting the thread section 88 through the arcuate slot 108 of 
flange portion 102. Cross pin 92 passes through the slot 108 to be 
received into slot 84 of one of the bosses 78 to non-rotationally receive 
the clamp pin 85. On the threaded section 88 of the clamp pin 85, a 
respective locking knob 110 is threadably carried and engages it and the 
head section 86 with the corresponding flange portion 102, 104 of the 
third bracket member 100 to retain this bracket member in a selected 
pivotal position or tilt position relative to the second bracket member 
72. Within a respective counter bore 112 of the locking knob 110, a 
retention member 114 is received, and is secured essentially non-removably 
to the clamp pin 85. That is, the retention member 114 may define a 
threaded blind bore (viewing FIG. 7) and be threadably received on the 
clamp pin 85 with a thread locking material to prevent removal of the knob 
110 except with the use of tools and deliberate force sufficient to break 
the thread locking material. 
Generally above and generally below the second bracket member 72, the third 
bracket member 100 includes a pair of webs 116 and 118, respectively, 
which connect and are integral with the flanges 102, 104. These webs 116, 
118 unite the flanges 102, 104 for pivotal motion in unison about the 
shoulder screws 98. As the flanges 102, 104 pivot on the shoulder screws 
98, the portion of these flanges adjacent to the clamp pin 85 sweep past 
this clamp pin so that this pin traverses the arcuate slots 108. 
Both in front of and behind the pivot screws 98, the flanges 102,104 each 
define a pair of depending ears 120, 122. A pair of guide ways 124 extend 
between the pairs of ears 120, 122. These guide ways 124 each define 
plural inwardly disposed teeth 126 spaced along their length (viewing FIG. 
8). Slidably received on the guide ways 124 is a carriage member 128. The 
carriage member 128 defines a laterally extending pair of recessed 130, 
each of which slidably receives a release bottom member 132, a portion of 
which extends outwardly of the recess 130 to be exposed on the carriage 
member 128. A respective spring 134 urges each of the release button 
members 132 outwardly so that respective teeth 136 thereof engage the 
teeth 126 of the guide ways 124. This carriage member 128 also defines a 
forwardly opening wedge-shaped recess 138 which receives a rearwardly 
extending tang 139 (only a portion of which is visible in the drawing 
Figures) of the night vision device 12. 
The night vision device 12 includes a conventional night vision viewer 140, 
which as illustrated, takes the form of an AN/PVS-7B goggle. This night 
vision goggle 140 includes a single objective lens 141, a housing 142, and 
a pair of eye pieces 144 aligned with respective eyes of the operator 10. 
To use the night vision goggle 140, the operator 10 places it in the use 
position depicted in FIGS. 1, and 2, and looks into eye pieces 144 to see 
an enhanced image representative of the low-level light from a night time 
scene which has entered objective lens 141. As those ordinarily skilled in 
the pertinent arts will appreciate, the night vision goggle 140 includes a 
power supply in the form of a battery pack internal to the housing 142. 
Internally of the night vision viewer, a power supply circuit provides 
power to an image intensifier tube, which is well known in the pertinent 
arts, and which supplies to the eye pieces 144 an intensified image in 
phosphor yellow/green light of the night time scene viewed via the 
objective lens 141. Also, the power supply circuit includes a 
magnetically-responsive sensor or switch, which is schematically indicated 
at 146 on FIG. 2. This sensor or switch 146 maintains electrical power 
supply to the goggle 140 once it is turned on by the operator 10 only so 
long as a magnetic field of sufficient strength is supplied to the switch 
146, similarly in operative concept to that described above with reference 
to the Kastendieck patent. 
However, as is illustrated in FIG. 4, the flip-up helmet mount 16 allows 
the operator 10 to flip up the night vision goggle 140 to a second 
position in which the goggle 12 is above the line of sight of the operator 
10. This flipped-up position of the night vision viewer allows the 
operator completely unobstructed vision with unaided eyes. As FIG. 4 
clearly shows, however, should the operator 10 forget to turn off the 
night vision goggle 140 before moving it to its flipped-up position, the 
phosphor yellow/green light emitted from the eyepieces 144 would be 
visible to possibly hostile personnel forwardly of the operator 10. This 
phosphor yellow/green light would appear as a pair of small yellow/green 
spot lights, and would be visible for a distance of several kilometers at 
night under battle field conditions. 
Accordingly, in order to provide the necessary magnetic flux to the switch 
146 while at the same time insuring that the magnetic field is removed 
from the switch 146 when the goggle 140 is pivoted to its flipped-up 
position, as depicted in FIG. 4, the flip-up helmet mount 16 includes a 
device (generally referenced with the numeral 148) which is responsive to 
a combination of gravity and centrifugal force effective during the 
flipping-up movement of the night vision goggle to turn the latter off. 
However, as will be explained, the device 148 allows complete freedom of 
head movement for the operator 10 without false turn offs of the goggle 
140. 
Viewing now FIGS. 2, 3, 4, 9a, and 9b in conjunction, it is seen that the 
device 148 includes a dependent housing portion 150 of the carriage member 
128. The housing portion 150 is located immediately above the magnetically 
responsive switch or sensor 146 of the night vision goggle 140, as is seen 
in FIGS. 2 and 3. This housing portion defines a S-shaped laterally and 
vertically extending cavity 152 (a backwards S-shape as seen in these 
drawing Figures). The cavity 152 is perhaps more accurately described as 
question mark shaped (? ), although the question mark is only right side 
up when the flip-up mount is inverted in its flipped up position seen in 
FIG. 4. The cavity 152 in longitudinal cross section includes a re-entrant 
cove portion 154, which is analogous to the top curlicue of the question 
mark shape. This cove portion 154 is separated somewhat from the remainder 
of the cavity 152 by a protruding lip feature 156. As is seen in FIGS. 3 
and 9b, the cove 154 is at the bottom of the cavity 152 when the flip-up 
mount 12 is in its use position. The cavity 152 is closed at one end by a 
cover part 158 of the housing portion 150, viewing FIG. 9a. 
Movably received in the cavity 152 is an elongate round cylindrical bar 
magnet member 160. This bar magnet member 160 provides sufficient magnetic 
flux to the sensor 146 to keep the night vision goggle 140 turned on so 
long as the magnet member 160 is in or immediately adjacent to the 
re-entrant cove portion 154 of the cavity 152, viewing FIGS. 3 and 9b. As 
FIG. 5 illustrates, if the user 10 turns his head to look vertically 
downwardly, the bar magnet 160 rolls to the bottom of the cavity 152, and 
remains adjacent to the re-entrant cove 154 because the cavity 152 is 
angulated rearwardly and upwardly relative to the user 10 and with respect 
to the horizontal. FIG. 6 similarly shows that even should the user turn 
his head upwardly entirely to a vertically upward direction of view, the 
bar magnet 160 will be retained in the cove portion 154 by the protruding 
lip 156. Consequently, the night vision viewer 140 will be maintained on 
regardless of the head movements made by the user 10. 
However, as FIG. 4 shows, when the user flips up the night vision goggle, 
the carriage member 128 is essentially inverted, and the bar magnet 160 
will be gravitationally moved out of and away from the cove portion 154 of 
cavity 152. The bar magnet member 160 is moved to an opposite end portion 
162 of the cavity 152 which is sufficiently far from the sensor 146 that 
the night vision goggle 140 is turned off. FIG. 4 shows that the bar 
magnet 160 is moved to the end 162 of cavity by gravity alone if the 
flipping-up motion of the goggle 140 is done slowly. That is, the angular 
movement of the goggle to its flipped-up position shown in FIG. 4 is 
sufficient that the round bar magnet member 160 will roll over the lip 
156, and will then fall to the other end 162 of this cavity. However, in 
the usual conditions of use of the night vision goggles 140, the 
flipping-up motion of the goggle would be just that--a quick flip-up 
motion. During such a quick flip-up motion, the night vision goggle 140 
and the carriage 128 move in an arc centered at the bore 61 of boss 60. 
Consequently, a centrifugal force is effective on the bar magnet member 
160, as is indicated on FIG. 9b with the arrow 164. This centrifugal force 
is effective to assist in quickly dislodging the bar magnet member 160 
from the cove portion 154, and to start this round bar magnet member 
rolling around the curlicue of the cavity 152 toward the opposite end 162. 
This combination of centrifugal force and the changing orientation of the 
cavity 152 with respect to gravity during the flip-up motion is effective 
to very quickly move the bar magnet member 160 away from the sensor 146, 
turning off the night vision goggle 140. This early moving of the bar 
magnet 160, and early turning off of the night vision device 12, has a 
great tactical advantage in many use conditions for the night vision 
device 12. That is, as soon as the night vision device 12 is started in 
its flip-up motion away from the user's eyes, the eyecups 144 come away 
from the user's face, which is then illuminated by the yellow/green light 
from these eyepieces. Potentially hostile personnel forward of the user 
may be alerted to the user's presence by this illumination. However, this 
light is for the most part blocked by the body of the night vision device 
itself. Also, the night vision device in its flip-up motion is on its way 
to a position (FIG. 4) in which the eyepieces 144 face toward the 
potentially hostile personnel. The light from the eyepieces 144 must be 
extinguished as soon as is possible in this flip-up motion to insure that 
little or no light is projected toward the hostile personnel. The early 
movement of the bar magnet member 160 of the present invention by a 
combination of gravitational and centrifugal forces effects this early 
turning off of the night vision device. 
As a result, by the time the goggle 140 reaches its flipped-up position 
depicted in FIG. 3, the phosphor yellow/green light from the eye pieces 
144 has been extinguished. Thus, the user 10 enjoys a much improved safety 
in the use of the night vision device 10, while still enjoying the 
convenience in use which is afforded by a flip-up mount. That is, the 
night vision viewer 32 is immediately available for its next use simply by 
flipping it down from the position of FIG. 3 to the use position 
illustrated by FIGS. 1 and 2. During this return to the use position, the 
bar magnet member 160 rolls from end 162 of the cavity 152 back to the 
curlicue end adjacent to and into the cove portion 154. Thus, when the 
user engages the switch of the goggle 140 to initially turn it on, this 
goggle stays on under the influence of magnet 152 acting on sensor 146. 
The user 10 need not remove the night vision goggle 140 from its mount in 
order to have clear, unobstructed vision with the unaided eyes. Further, 
the operator 10 need not remember to turn off the goggle 140 each time a 
view with the unaided eyes is desired. Simply moving the goggle 140 up to 
its flipped-up position will safely extinguish the phosphor yellow/green 
illumination from the eye pieces 144, as well as saving battery power by 
turning off the goggle 140. 
In order to provide retention of the night vision goggle 140 in either of 
its use or flipped-up positions, the first bracket member 18 includes a 
pair of laterally and forwardly extending yieldably shape retaining tongue 
portions 166, 168. These tongue portions are arranged as an upper tongue 
and a lower tongue, one on each side of the boss 60. Each of these tongue 
portions 166, 168 defines a respective one of a pair of transverse grooves 
170. The web portion 76 of the second bracket member 72 includes a 
laterally elongate rib part 172 extending toward the boss 60. This rib 172 
is receivable into either one of the grooves 170 to releasably retain or 
detent the second bracket member in either the use position of FIGS. 1, 2, 
and 3, or in the flipped-up position of FIG. 4. The second bracket member 
72 moves through an angular movement of substantially 180 degrees between 
its use and flipped-up positions. 
In the use of the flip-up helmet mount 16, the operator 10, engages the 
hook member 20 with the brim of his helmet 14 with the abutment surfaces 
38 of the first bracket member 18 in engagement with the front of the 
helmet, extends the strap assembly 47 to the rear of the helmet, and hooks 
the hook member 58 at the rear edge of the helmet. The ratchet tongue 
member 54 in combination with the adjustability of strap 46 at cross bars 
42 is used to adjust the length of the strap assembly 47 for a snug fit on 
various sizes of helmets. Final tightening of the flip-up mount 16 is 
effected with the over-center buckle portion 56. 
As illustrated, the flip-up mount 16 is shown in use on the standard U.S. 
Army Kevlar composite helmet. However, the flip-up mount 16 can easily and 
inexpensively be adapted for use on other helmets having different brim 
shapes by providing a different hook member 20 configured for the 
particular helmet. Once the flip-up mount 16 is secured to the helmet, the 
night vision goggle 140 is attached by inserting the tang 139 into recess 
138, and pivoting the goggle to its use position seen in FIG. 1. As so 
positioned the bar magnet member 160 is positioned to maintain the goggle 
140 turned on once the operator 10 switches it on. When the operator 10 
flips the goggle up to its position seen in FIG. 4, the goggle is 
automatically turned off, as explained above. However, in the event the 
operator does not fully engage the detent features (tongue 168 and rib 
172) in this flipped-up position of the goggle, the goggle will not fall 
freely down but will still be supported because of the selected frictional 
engagement of the journal member 63 in bushing 62. 
In view of the above, it is easily appreciated that the present flip-up 
helmet mount additionally provides a very strong, rugged, and reliable 
mount for the night vision goggle 140, and one which is not frail, easily 
damaged, or readily impeded or compromised in its operation by the 
sometimes rough use and severe operating environments encountered in 
police or military uses, for example. The nested first, second, and third 
bracket members of the present flip-up helmet mount are individually very 
strong, and further mutually support one another in the assembled mount 
16. The broad-based hook member 20 provides secure mounting of the flip-up 
mount 16 to the helmet 14, and is yet easily and quickly removed by the 
simple releasing of the over-center buckle 56. The flip-up mount-16 can be 
adapted to a variety of helmets easily and cheaply with the simple 
provision of an appropriately configured hook member 20. 
Finally, the magnetic device 148 has only a single moving part, is 
responsive to and dependent upon only very dependable forces such as 
gravity and centrifugal force in its operation, does not rely for its 
operation on any other mechanization, such as links, springs, levers, or 
gears, for example, and is consequently very reliable in its operation. 
Additionally, the magnetic device 148 is totally closed to environmental 
contaminations and well endures the rough handling and severe operating 
environments which may be encountered in the use of the night vision 
goggle 140 and flip-up mount 16. 
While the present invention has been depicted, described, and is defined by 
reference to a particularly preferred embodiment of the invention, such 
reference does not imply a limitation on the invention, and no such 
limitation is to be inferred. The invention is capable of considerable 
modification, alteration, and equivalents in form and function, as will 
occur to those ordinarily skilled in the pertinent arts. Accordingly, the 
depicted and described preferred embodiment of the invention is exemplary 
only, and is not exhaustive of the scope of the invention. Consequently, 
the invention is intended to be limited only by the spirit and scope of 
the appended claims, giving full cognizance to equivalents in all 
respects.