Optical: systems and elements – Having significant infrared or ultraviolet property – Having ultraviolet absorbing or shielding property
Patent
1991-11-21
1993-03-02
Arnold, Bruce Y.
Optical: systems and elements
Having significant infrared or ultraviolet property
Having ultraviolet absorbing or shielding property
359350, 359892, 2 12, 2 15, 219147, G02B 522
Patent
active
051914689
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to welder's helmets of the kind which are fitted with so-called fast filters, i.e. a light filter which remains comparatively clear until subjected to the effect of welding light, whereupon the filter darkens, normally through switching of the polarization of one or more liquid crystal layers in combination with polarizing filters.
Helmets that are fitted with permanent filters are used solely during an actual welding operation, and when no welding is in progress, the filters, and possible also parts of the helmet, are moved out of the way. Welder's helmets fitted with so-called fast filters, however, are normally worn constantly during work and may often be provided, comfortably, with "air conditioning" and perhaps also with earphones or hearing protectors, these facilities being appreciated in some industrial environments.
One drawback with helmets of this kind is that because the wearer can only see straight ahead through the fast filter, he loses the comprehension of space. Many workmen find this uncomfortable and the lowered perception may result in an accident or injury.
An object of the invention is to provide an improvement in this regard. This object is achieved in accordance with the invention with a welder's helmet having the characteristic features set forth in claim 1.
Thus, according to the invention, separate filter windows are disposed on respective sides of the fast filter. These windows will preferably have a given filter factor, in order to give equilibrium and freedom from dazzle. The welding light generated will result in significant illumination of the surroundings, as will also the light generated by other welding operations, particularly in workshops in which several welders are at work. Accordingly, the filter windows will preferably have a given filter effect in the visible range and will also preferably give low transmission in the UV-range and in the IR-range.
Known to the art are welder's helmets that are fitted with conventional filter glass and which have a large, integrated front window. This front window has a higher density in the center thereof, so as to protect the wearer against welding light which falls immediately on the eyes, and a lower density at the sides of the window. One problem with a helmet construction of this kind is that direct welding light will enter the helmet and illuminate the face of the wearer, such that the face becomes suffused with light within the helmet. The illuminated face of the wearer of the helmet is reflected in the rear side of the filter part of higher density, therewith decreasing the contrast. Furthermore, the general brightness to which the eyes are subjected causes the eyes to adjust to an excessively high light density. When the welding operation has been completed, it takes time for the eyes to adjust to the reduced brightness. An object of the invention is to improve the field of vision, without suffering these drawbacks.
BRIEF DESCRIPTION OF THE DRAWING
The invention will now be described in more detail with reference to an exemplifying embodiment thereof and with reference to the accompanying drawing, which illustrates a welder's helmet.
DETAILED DESCRIPTION OF THE INVENTION
The welder's helmet 1 illustrated in the drawing comprises a curved, plastic face mask. The helmet further comprises a head strap 2 which is tightened around the head of the wearer, so as to support the helmet. The face mask is pivotally attached to the head strap at two points thereon, one of said points being referenced 5 in the drawing while the other point on the other side of the face mask is not visible in the drawing. The face mask can thus be pivoted about these pivot attachments, so as to enable the mask to be raised and leave the face free.
The helmet further includes a framed welding glass 3 which is mounted opposite the position of the wearer's eyes. This glass is of the fast-filter type and may be a filter glass of the kind marketed by us under the trademark "Speedglas", which comprises in sequence an interfe
REFERENCES:
patent: Re29684 (1978-06-01), Gordon
patent: 3756692 (1973-09-01), Scott
patent: 3868727 (1975-03-01), Paschall
patent: 4039254 (1977-08-01), Harsch
patent: 4707860 (1987-11-01), Holmstrom
patent: 4863244 (1989-09-01), Fuerthbauer et al.
Arnold Bruce Y.
Hornell Elektrooptik AB
Ryan J. P.
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