Note: Descriptions are shown in the official language in which they were submitted.
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BCCP 1 2
I~5PROVE~NTS IN OR ~EL~TING ~O PROTECTIVE H~3LMETS
This invention concerns improvements in or relating to
protective helmets for use by operatives in indu~trial
environments.
In particular, although not exclusively, the invention has
reference to auch helmets for use in the mining or quarrying
industrie~ wherein the need for protective headwear is
e~pecially acute. Protection ia required not only to
prevent physical injury but also to avoid and indeed minimise
damage to the respiratory organ~, to the aural, ocular and
olfactory sense~.
Protective helmets in the form of powered helmet respirator~
are already known and generally include a protective ~hell
within which i5 provided means for introducing a filtered air
3upply between the wearer' 9 face and a visor which may assume
a f$xed dispo~ition on the shell or may be pivotally mounted
outside the #hell to allow movement into and out of an
operable, ie protective, position in front of a wearer'~ face.
It is also known to provide protective heImets with ear
defender~ mounted externally of the shell and pivotable
between operative and inoperative position The problem is
that because of their location exteriorly of the shell, they
can become snagged on equipment which occa3ions discomfort to
the wearer, and damage or dislodgement of the ear defender.
It has been and remain~ a feature of known powered helmet
respirators that they are cumbersome and also heavy and
poorly balanced when provided with respirator fans and
filter, face visor and ear defenders, with conse~uential user
res1stance.
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It is therefore an object of the present invention to provide
an improved protective helmet.
According to the invention there is provided a protective
helmet including a protective ahell for accommodating a
wearer's head, a visor at the front part of the shell and
retractable therewithin, the shell being provided with an ear
defender at each side thereof, each ear defender being
substantially within the profile of the shell, an air duct
defined within the shell and having an inlet towards the rear
part of the shell and a number of outlets associated with the
front part of the shell and diracted on to the internal
surface of the visor and at least some of its marginal edges
which in use extend adjacent the wearer's face, a filter
associated with the duct, and an air mover for introducing
air to the duct.
Advantageously the air duct extends from the occipital region
to terminate at the front part of the shell in the or each
outlet which in use supplies air to the top part of the visox
when in its operational extended position in front of a
wearer' facej such that the interior of the visor is ~wept
wi~h air. Preferably thar~ is provided a plurality of
outlets for the air duct, the outlets being directed ~uch as
in use to ~weep the interior of the vi~or with air and to
target the marginal edges o~ the visor lying adjacent the
wearer's face thereby to provide a pneumatic seal therearound
to minimise the ingrass of injuriou~ atmospheric pollutant~.
An inner protective s~in is disposed within the shell in
spaced relation thereto, the skin conveniently defining the
duct between it and the internal surfa~e of the shell.
The air duct extends over a sub~tantial part of its length
between the shell and the inner skin, the inner skin being
bifurcated at the front part of the ahell to provide both the
number of outlets and the space for visor retraction.
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The shell may be formed to give at it3 rear part an outer
wall and at its front part an inner wall, the front part
being provided with a cover to define a channel within which
the visor may retract. The cover in such an embodiment is
so formed as to give the helmet a continuous or substantially
continuous outer profile. The cover may for convenience be
removable and replaceable, suitable fixtures being provided
for that purpose.
The filter may conveniently extend across the inlet ko the
duct, and the air mover may be disposed within the duct in
rearwards of the crown of the shell. The air mover is
constituted by at lea#t one fan, preferably hattery powered.
~he visor may be removably mounted in a carrier having a
renewable transparent section constituting the visor per
se. Alternatively, the carrier may comprise a frame into
which a renewable transparent section may be insertabla.
The visor carrier may be slidably mounted to the interior of
the shell by means oP side supports each having slot~ with
which bushes on the carrier engage to afford in use and
arcuate slidin~ motion for the visor into and out of an
operative position in front of the wearer's face.
~ach ear defender may conveniently be provided substantially
within the profile of the helmet thereby to secure that there
are no protuberances which in use could constitute a source
of danger by snagging.
The front part of the shell may be peaked and be provided
with protective side cheeks which in use complement the vi or
and the ear defender# to provide continuity arGund the
wearer's face. The side cheeks form a proximity seal
between the visor frame and the wearer's face, thus providing
enhanced protection from side drau~ht~ of contarninated air.
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The front part of the shell may be provided with a mount for
a lamp such as is used in underground mining, the lamp being
battery powered. In the one embodiment described above, the
cover would be provided with the mount at the front of the
helmet. The removable cover provides a degree of
versatility whereby different fitments thereto can be
provided on a range of covers.
By way of example only, one embodiment of protective helmet
according to the invention is described below with reference
to the accompanying drawings in which:
Figure 1 i8 a side view of the helmet partly
in section and in position on a
wearer~s head;
Figure 2 is an interior view of the helmet.
Figure 3 is a vertical section through the
centre line of an ear dsfender of the
helmetj and
Figure 4 i~ an exploded view of the ear
defender 3hown in Figure 3.
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Referring to Figures 1 and 2 of the drawings, there is shown
at 1 a protective helmet in the ~orm of a powered helmet
respirator in po~ition on a wearer's head 3, the re~pirator
comprising a protective shell 2 having a rear part 4, a crown
6, a front part 8 and 3ides 10. A head harness (not shown)
2D is provided within the ~hell 2 for comfortabIy seating the
respirator on the wearer's head 3.
An inner skin 12 extends from the rear part 4 to the front
part 8 and de~ines in the occipital region an air inlet 14
acros~ which there is provided a filter 16 of suitable
~ibrous material. The filter 16 i3 clipped into a holder 13
and can thu~ be easily di3mountable and replaceable.
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A further inner skin which CompriSe# parts of the shell 4, 6,
8 extends through 4, 6 and downwards through 8 terminating in
a plurality of outlets 20 in the form of ~lots. An air
duct 22 is thus defined within the shell 2 between it~ inner
surface and the skins 12 and 4, 6 and 8.
A front cover 9 is fixed to the shell 2 to provide a smooth
profile to the helm~t exterior and with the front part of the
protective shell 8, provides a space 42 into whiah the visor
30 may retract.
An air mover in the form of two battery-powered fans 24 i~
located within the duct 22 on sound-absorbing mount~ 26
rearwards of the crown 6 of the shell 2. The power for the
fans 24 i~ conveniently provided by a body mounted battery
pack (not shown) which is of such capacity as additionally to
power a lamp (not ~hown) releasably fixable to the front part
9 on 2 bracket 29 provided for that purpose ~Figure 1).
~ visor 30 comprising a carrier 32 which is r21easably fixed
to a txansparent window 34 i~ slidably and pivotally mounted
on supports 38 fixed to the sides of the helmet shell 2, with
bushes 39 attached to the vi~or carrier 32. The supports 38
have curved ~lots within which ~he bushe~ are adapted to
~lide.
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The visor 30 i~ retractable within a space 42 defined between
part 8 of the shell 2 and the inside wall of the outer cover
9. The visor 30 ha~ a ~top for abutting a cut-off ~witch
(not shown) euch that when the visor is fully extended in
front of the wearer's face, the power to the fan 24 is
initiated. Additionally, in this position, the visor is
sealed against the inner face of the outer cover 9 by a
sealing strip 21. The visor may alternatively seal again~t
the outer face of the shell 8 along it~ lower edge. A
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limited pivoting motion about the lower bush 39 may be
provided to enable the lower part of the visor to move closer
to the wearer's face, and is achieved by a small rece~s in
the slot in the support 38 into which the upper bush may move.
In its operative position as shown in Figure 1, the visor 30
in conjunction with cheek plates 52 and ear defenders 60, to
be described later, on the sides 10 of the shell 2 gives
panoramic protection for the front and sides of the wearer's
face.
The visor 30 may be provided with a range of proximity seals
5not shown) to reduce the distance between the visor margins
and the wearer's face for the purpose of ~urther minimising
the ingress of contaminated air into the wearer's breathing
zone.
With reference to Figure 1, there i~ shown on one side of the
powered helmet respirator 1 an ear de~ender 60 which is
~ecured to the shell 2. A corresponding ear defender ~not
shown) is provided on the other aide o the shell. The ear
defender 60 conform~ to the general profile of the helmet 1.
Re~erring now more specificall~ to Figures 3 and 4, each ear
defender 60 inaludes an outer aover 101 provided to form an
attachment to the helmet 1 and to contain a main body shell
102 of the defender. The main body shell 102 ia attached in
spaced relation to an apertured back plate 103 enclosing
2S sound absorbing material 104 therebetween.
A cruciform spring 105 is held in po0ition within the body
~hell 102 and is engaged by a telephone activator/release
knob 106 provided with a sealing face 106a for abutting a
seat 114 formed around an orifice 114a extending axially
through the body shell 102, the arrangement being such that
when the knob 106 is depre~ed against the action of the
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spring 105, the orifice 114a iB opened allowing sound to pa~
inwardly of the ear de~ender in use toward~ the ear of a
helmet wearer through the apertured back plate 103. Release
of pressure on the knob 106 allows the spring 105 to return
the knob to a sealing position in relation to the orifice
114a thereby restoring the ear defender to it~ noise
attenuating role.
An ear qeal 113 is secured to the backplate 103 in a po~ition
comfortable to the wearer, and forms a contact seal with that
part of the weaxer'~ head immediately surrounding the ear.
Wire-form springs 107 support the body shell 102 inside the
outer cover 101 such that when the body shell 102 i~ pushed
into the cover 101, the springs 107 hold the shell 102
thexein using the 'over centre' principle. When the body
shell 102 is pushed in the oppo~ite direction, the spring3
107 press the ear defender seal 113 again~t the wearer's head
wlth the co rect pres~ure for providing noise attenuation.
The springs 107 are attached to the outer cover 101 using
vibration damper~ 108.
In u~e, in order permit the u~e of a telephone, the telephone
earpiece tnot ~hown) i~ brought into contact with the knob
106 and pres~ure applied suPficiently to depress th~ ~pring
105 and thus open the orifice 114a, The outer part of the
telephone earpiece is pre~sed against a seal 110 provided on
the body shell 102 to exclude external noise. In this mode,
sound from the telephone ear piece is transmitted via the
orifice 114a, through the body shell 102 and the apertured
backplate 103 to the wearer's ear. Removal of the telephone
earpiece from contact with the knob 106 automatically allows
the ear defender to revert to its full attenuation mode.
A reflective Rtrip 109 is wrapped around that part of the
body ~hell 102 ~uch that when the ear defender i~ in it~
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non-operative (parked) position, when no sound attenuation is
effected, the reflective strip i8 visible externally of the
outsr cover 101. When the ear defender is in its operative
position, the reflective strip 109 is not readily visible.
The outer cover 101 i8 fitted with means for a-ttachment to a
helmet in one of several positions to suit the width of the
wearer's head. The attachment may be effected by screws 112
or by any other suitable means.
The relatively forward part of the outer cover 101 i8
provided with a pair of tabs 115 having a serie~ of holes
capable of accepting a visor atop peg 111. The peg 111 ia
secured into a pair of holeY best suited to the wearer to
provide a comfortable and effective position for holding the
visor clo~e to, but not in contact with the wearer~ face.
In use, the helmet 1 fits snugly and comfortably on the
wearer~s head 3 initially with the visor 30 in its retracted
position within the space 42, the fans 24 being stationary.
Downward movement of the visor 30 brings it into its
operative position as shown in ~igure 1. At the same time
release of the cut-off switch ~not ahown) allows power to be
restored to the fans 24 which accordingly induce an air flow
through the inlet 14 and the filter 16 into the duct 22 and
thence to the outlets 20 whence it travels downwards between
the visor 34 and the face of the wearer to ventilate same
with filtered air and to provide cooling. By virtue of the
slot form of the outlets 20 and the close fitting of the
visor 30 with the cheek plates 52 and ear defenders 60, a
screen of air passes in a concentrated flow over the nose and
mouth of the wearer, the air flow passing out between the
lower margins of the visor 30 and the wearer's chin, and
lower part~ o~ the cheeks.
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The ear defender~ 60 are within the general profile o the
shell 2 of the helmet 1, and present no projection likely to
be a hazard. Operation of a fully integrated and custom
designed helmet according to the present invention in which
the ear defenders are within the profile of the shell enables
noise attenuation to be achieved effectively.
The present invention thus provide~ a comprehensive and
versatile powered helmet respirator possessing an optimum of
protective features whilst being le~s cumbersome and less
weighty than its antecedents. Equally, replacement of the
filter and of the vi~or window are facilitated thus reducing
cost and time spent in repair.
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