Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Locking device for helmet visor
BACKGROUND OF THE INVENTION
The present invention concerns a locking device
enabling a helmet visor to be held in a given position.
Helmets comprising at least one visor lock are used in
particular, although not exclusively, by aircraft and
helicopter pilots.
Por example the helmet bearing the reference OS 458,
manufactured by the Optique Scientifique Gueneau company,
comprises two retractable visors, one transparent and the
other forming a sunscreen
The transparent visor is intended, in particular, to
protect the pilot in the event of a shock inside the
cockpit and to protect him from the blast in the event of
ejection or canopy damage; for this reason the transparent
visor must remain lowered for the whole duration of the
flight. On the OS 458 helmet the two visors are maneuvered
~; using two mechanisms, one on the left-hand side of the
helmet, the other on the right-hand side. The transparent
visor, controlled by the right-hand mechanism, is held in
the lowered position by a locking device comprising a
spiral spring; this locking proves insufficient in the
'~ case of ejection at high speed.
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SUMMARY OF THE INVENTION
The present invention eliminates this disadvantage,
while enabling the locking device according to the
25 invention to be mounted on equipment initially equipped
with~a locking device according to the prior art.
The locking device described uses a safety catch
providing positive locking. ~
The present invention provides for a helmet locking
30 device to lock a first mechanical assembly comprising a
v1sor, with respect to a second mechanical assembly
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comprising a helmet shell, the first assembly being
rotatably mounted about a main axis for rotating with
respect to the second assembly in such a way that it can be
moved between two extreme angular positions, the device
comprising a secondary axis approximately parallel to the
main axis, a safety catch pivoting around the secondary
axis, a spring to hold the safety catch, and a hook to
engage the catch when the first assembly is in a
predetermined one of the two extreme positions, the spring
acting on the catch to hold it in the hook, and in which
the catch with the spring forms part of one of the two
assemblies, and the hook forms part of the other one.
BRIEF DESCRIPTION OF THE DRAWING
The invention will be better understood and other
characteristics will appear on reading the description
given below with reference to the appended drawings of
which:
- Figure 1 represents a helmet according to the prior
art,
- Figure 2 represents a partial view of a helmet
according to the invention.
On the different figures, corresponding parts are
2S designated by the same references.
MORE DETAI~ED DESCRIPTION
Figure 1 represents the anti-shock helmet made by
Optique Scientifique Gueneau under the reference OS 458 and
intended in particular for aircraft pilots. This helmet
comprises a helmet shell 1, and two visors one of which is
a sunscreen and the other, 2, a transparent screen; the
two visors are controlled by mechanisms situated
respectively on the left-hand side and on the right-hand
side of the shell. In Figure 1 only the transparent visor,
2, is shown; its two extreme positions when it is lowered
and raised, 2a and 2b respectively, are indicated.
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The visor 2 turns about a mechanical axis, A, fixed to
the shell and is attached to an operating lever 5. A
spiral spring 6, one end of which is fixed to the axis A,
acts on the lever 5 to push and hold the visor 2 to its
5 lowered position.
A formed plate 3, fixed to the shell 1 by five screws
such as 31, protects the lever 5 and its spiral spring
which are enclosed between the external wall of the shell
and the plate. A cutaway X, in the plate 3, reveals the
10 lever S and the spring 6. The plate has an arc-shaped
hole 30 in which lies the mechanical axis B fixed to the
lever 5 and parallel to the axis A. An operating knob 40,
fixed to the axis B, enables manual raising or lowering of
the visor 2. The visor 2 is maintained in raised position
15 by an automatic locking not shown on the diagram.
The force exerted by the spiral spring 6 may be
insufficient, under certain conditions of use, to hold the
visor 2 in lowered position. This is why the helmet
according to Figure 1 has been modified, as indicated in
20 Figure 2.
Figure 2 shows how, by modification of the original
operating knob 40 and by addition of a hook 10, the visor
is held positively in the lowered position.
The hook 10 is fixed to the helmet by at least two of
25 the screws holding the plate 3 to the shell 1.
The original knob 40 is replaced by a knob 4 which is
shown partially cut away; the edges Y of this cutaway have
been hatched in Figure 2.
The body 41 of the knob 4 is considerably larger than
the original knob 40 so that it can accommodate a
mechanical assembly which can be seen through the cutaway
and which, together with the hook 10, constitutes a lock
preventing the visor 2 from raising accidentally.
The body 41 of the knob 4 is mounted, in the same way
35 as the knob 40 in Figure 1, on the axis B which can move
along the arc-shaped slot.
;~ The mechanical assembly contained in the body of the
~ ~ ~ knob comprises:
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- a catch 7, pivoting about a mechanical axis C, fi~ed
to the body ~1 of the knob 4 and parallel to the axes A and
B; this catch engages in the hook 10 when the visor is
lowered,
- a coil spring 8, one end of which is fixed to the
body of the knob and the other end of which exerts pressure
on the catch 7 holding it engaged in the hook 10,
- and a release button 9 formed of a head external to
the body 41 of the knob 4 and attached to a pin which
slides within the body of the knob.
In addition, an elastic stop 11 intended to absorb
play is fixed to the body of the knob in a position where
it comes into contact with the hook lO when it engages the
catch 7. The visor 2 is lowered by exerting pressure with
the thumb of the right hand, as indicated in Figure 2, on
the rear part of the body of the knob; at the end of
travel the catch locks in automatically.
The visor 2 is raised simply by pressing with the
index finger of the right hand, as indicated in Figure 2,
on the head of the release button 9; this action brings
the pin of the release button 9 into contact with the
catch 7 which then pivots about the axis C and disengages
the hook 10.
It should be noted that the position of the axis C is
such that the force on the visor, exposed to a blast, is
not transmitted to the spring 8.
The present invention is not limited to the example
described. For instance, the mechanical assembly contained
in the body of the knob 4 in Figure 2 may be modified by
making the stop 11 adjustable by a screw system in order to
adapt the visor position to the shape of the pilot's face.
To do this the stop 11 is attached to the head of a screw
and the hook 10 comprises two parts: the screw attached to
the stop and a fixed part which is connected to the shell 1
in the same way as the hook 10 in Figure 2, and into which
the stop screw is screwed to a greater or lesser depth. It
is then the head of this screw which constitutes the hook.
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in Figure 2, this hook and therefore the hook of the
catch 7 must be slightly shifted downwards because of the
presence of one of the two screws which flx the hook 10 to
the shelL l.
In the same way, although the above description
concerns a specific helmet, designed for aircraft and
helicopter pilots, the invention is applicable to any
helmet equipped with a visor and in particular to helmets
for motorcyclists, car drivers and people practising
10 hazardous sports.
Very generally speaking, the invention concerns any
device for locking a visor in an extreme position, i.e. in
raised or lowered position, which comprises a mobile catch
and a fixed hook; and, inversely to what is described with
reference to Figure 2, the catch may have its mechanical
axis fixed to the shell of the helmet while the hook may
pivot with the visor.
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