Note: Descriptions are shown in the official language in which they were submitted.
-` ~03B3~
FACE SHIELD FILTER PLATE RETENTION
This invention relates to face-protecting devices
of the type utilized by welders and more particularly to
improvements in retaining filter plates in the viewing ports
thereof.
Background Of The Invention
Welders and others wear shields or helmets to pro-
tect their faces and eyes from infrared, ultra-violet and
part of the visible light emanating from the work area. To
this end, the shields are provided with a viewing port which
halds an eye-protecting light filter screen of a translucent
material to filter light rays, particularly ultra-violet and
infrared rays. Usually a relatively inexpensive clear glass
or plastic is placed over the light filtering screen to pro-
tect the filter from flying sparks and molten metal such as
encountered in welding.
Filter plate as used herein encompasses both
panes of material, the one that filters radiation and
the overlying protective glass or plastic plate which
is generally used to protect the filter. Prior art filter
plate holders are generally inserted into the welder's shield
or helmet from the rear or interior by snap action and
generally involve a mechanism whereby the filter plates are
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held against the inside of the helmet surface by spring retainer
meanæ.
Recent industry safety regulationæ impoæe more stringent
requirements on eye-protecting devices such as welder's shields or
helmet$ and require that they meet certain standards, particulary
with respect to increased impact resistance. Filter plate holders
which are inserted in shields or helmets from inside the helmet
and held against the interior surface of the shield often do not
meet the more stringent standards with respect to impact
resistance.
SuaaarY of the Invention
The present invention provides means for retaining
filter plates over the view port of a face-protecting device
whereby the filter plates are supported on the exterior of the
face-protecting device by a recessed support ledge and retained in
positlon by a filter plate retainer having fastening means for
attachment to the face protecting device.
Specifically, the invention provides in a face-
protecting device having a viewing port therein, the improvement
which comprises supporting a filter plate on a support ledge of a
face-protecting device and retaining the filter plate on the
exterior of said face-protecting device by a flexible filter plate
retainer provided with integral fastening means projecting
inwardly therefrom and means for adjustably engaging the fastening
mean~ with the face-protecting device.
The invention also provides a filter plate retainer for
use with a face-protecting device having a viewing port therein
with an adjacent support ledge, said retainer comprising an
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integral flexible frame of a size and shape to surround the
viewing port, said frame carrying integral fastening means
projec~ing inwardly therefrom and means for adjustably engaging
the fa$tening means with the face protecting device.
The invention also provides in combination, a face-
protecting device having a viewing port therein with an adjacent
support ledge and a filter plate retainer comprising an integral
flexible frame of a size and shape to surround the viewing port,
said frame carrying integral fastening meanæ projecting inwardly
therefrom and means for adjustably engaging the fastening means
with the face-protecting device.
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In one presently preferred embodiment, the present
invention involves a filter plate retainer for use with face-
protecting devices having a viewing port therein surrounded
by a slotted recessed support ledge. The retainer comprises
an integral flexible frame of a size and shape to surround
the viewing port. The frame is provided with fastening means
for attachment to the face-protecting device from the
exterior thereof. The retainer is attached to the exterior
of the face-protecting device over the filter plates. The
retainer is adapted for use with face shields in general
having a recessed support ledge surrounding the viewing port
and provided with means to receive the fastening means pro-
vided on the retainer.
Description Of The Drawings
Figure 1 is a perspective partial view of a typical
face-protecting device such as a welder's shield or helmet
with the filter plate retainer of the invention attached in
place.
Figure 2 is a view similar to Figure 1 showing the
méthod of assembling the filter plates and plate retainer for
attachment to the device.
Figure 3 is a plan view of a plate retainer in
accordance with this invention.
Figure 4 is a view taken on the line 4-4 of
Figure 3.
Figure S is a view taken on the line 5-5 of
Figure 3.
Description Of Preferred Embodiments
The filter plate retainer of this invention is
adapted for exterior attachment to a face-protecting device
such as a welder's shield or helmet, a typical device being
designated by the numeral 10. Such devices have a view port
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11 over which one or more filter plates 13 and 14 are placed.
Usually a gasket 15 is employed between the plates.
According to one presently preferred embodiment,
the plate retainer comprises a generally rectangular flexible
S frame 16 formed of L-shaped flanged top 18, bottom 20 and
sides members 22 and 24 which form an integral unit. The
retainer is formed of a sturdy, non-flammable, heat resistant
material such as glass-filled nylon or the like. The size of
the retainer will vary according to the size and shape of the
viewing port of the welder's shield which are typically
rectangular in shape and 2" X 4-1/4" or 3" X 5-1/4" or 4-
lt2" X 5-3/4" in size. The retainer can be readily formed by
known procedures, such as injection molding.
In one preferred form, the outer peripheral facing
surfaces of the top, bottom and side members of the frame
member are bevelled inwardly as at 18a, 20a, 22a and 24a so
as to create an attractive picture frame effect. The top,
bottom and sides of the frame function as cantilever spring-
like elements to resiliently grip the filter plates. Four
notches 27 are provided, preferably at each corner of the
frame, which permit the said frame members to more freely
flex.
The frame is also provided with inwardly projecting
perimeter flanges 18b, 20b, 22b and 24b. These perimeter
flanges surround the edges of the stack of filter plates 13
and 14 and gasket 15 (if used) and maintain the plates in
alignment. These perimeter flanges project inwardly a
distance less than the thickness of the stack of filter
plates to be retained. In addition to holding the filter
plates in alignment and providing support to the frame, the
perimeter flanges also function as a barrier to light rays
emanating from welding activity.
As shown in the drawings, closely adjacent to each
side 22 and 24 of the frame 16 are fastening means comprising
two spaced planarly aligned locking fingers designated by the
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numerals 30, 32, 34 and 36 which extend inwardly in a plane
generally normal to the frame. One or more gripping barbs 40
are provided on either the interior or exterior surfaces of
each of the locking fingers. The barbs on one locking finger
are off-set, or not planarly aligned with the barbs on the
planarly aligned adjacent locking finger so as to accommodate
filter plate stacks of different thicknesses and to lock them
snugly in the viewing port of the face-protecting device.
Thus, the barbs 40 on locking finger 30 are non-planarly
aligned with barbs 40 on the adjacent locking finger 32 and
the same is true with the barbs on the adjacent locking
fingers 34 and 36. In a less preferred embodiment, a single
locking finger can be used on each side of the frame and with
a desired number of relatively small finer barbs thereon.
The use of two locking fingers carrying relatively larger
barbs is preferred for better tolerance of abuse and better
wear resistance. Other fastening means, such as, for
example, rotary tab members adapted to pass through keyhole
slots in the shield can be employed.
The plate retainer of this invention can be used
with various face-protecting devices such as welder's shields
or helmets and the like, such as, for example, as shown in
United States patent Nos. 1,508,907, 3,257,667, 3,577,563 and
others. The only modification of some such shields is that
they be provided with a slotted recessed support ledge 42
around the periphery of the viewing port. If desired, such
recessed support ledge 42 can be provided with spaced
upstanding lugs 43 to serve as centering means for the
innermost filter plate. The retainer frame is pushed in
around the centering lugs 43. The face-protecting device
should also be provided with slots 44 in the sides of the
shpport ledge 42 to receive the gripping fingers 30, 32, 34
and 36 of the filter plate retainer.
In assembling the eye-protecting piece in the
protective shield, a translucent light filter plate 13 is
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placed on the recessed support ledge 42 of the shield. Then,
if desired, a gasket 15 is placed thereover followed by a
protective glass or plastic plate 14. The retainer frame is
then placed over the stack of filter plates with the locking
fingers 30, 32, 34 and 36 being pushed through the slots 44
in the shield support ledge 42. Depending upon the thickness
of the stack of filter plates, the flat surface of one of the
barbs 40 on the locking fingers at each side of the frame
will then engage the sharp edge 45 of the support ledge 42.
The range of resilient grip of the frame will ideally be
equal to or greater than the pitch or spacing between
adjacent barbs.
The slots 44 in the shield support ledge 42 are
preferably somewhat larger than the locking fingers for
ease in engagement and disengagement which can be easily
accomplished by laterally deflecting the flexible fingers
to disengage the barbs from the edge of the support ledge.
Because of the required clearance of slots 44, preferably
a rub rail 48 is provided on the exterior of the inwardly
projecting side flanges 22b and 24b of the frame so as to
prevent the possibility of light entering the slots 44 when
the eye-piece is assembled. The rub rails 48, by virtue of
an interference fit press firmly against the side perimeter
walls of the recessed view port of the shield thus causing
the rub rails' supporting flanges 22b and 24b to flex in-
wardly. By virtue of this inward flexure and the flexibility
of the retainer frame itself, the locking fingers that carry
the barbs press firmly against the edge of the slots in the
shield support ledge. Notches 50 and 52 are preferably
provided in the sides and top and bottom of the frame so as
to accommodate and fit around lugs 43 on the support ledge of
the face shield.
As will be appreciated, the filter plates are
located on the outside of the face-protecting device and are
firmly retained against a recessed support ledge surrounding
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the view port by the filter plate retainer of this inven-
tion. This insures that the filter plate exhibit good
resistance to impact forces. Moreover, with the filter plate
retainer of this invention, filter plates can easily be
changed or inserted without the use of special tools. Filter
plates, including a gasket between the plates, can be readily
loaded into the view ports of a face-protecting device from
the outside of the device and firmly retained by the retainer
which is substantially flush with the face of the device.
Those modifications and equivalents which fall
within the spirit of the invention are to be considered a
part thereof.
WHAT IS CLAIMED IS:
