Improvements in Vault Lights or Prism Tiles.
Year: 1897

page_text: Improvements in Vault Lights or Prism Tiles.
I, OLIN HANSON BASQUIN of No. 1410 Marquette Building, Chicago, County of
Cook and State of Illinois, United States of America, Gentleman, do hereby de-
clare the nature of my invention, and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement: -
My invention relates to vault lights for diffusing and distributing the light and
bas for its object to provide the new and improved lense or device for this purpose
illustrated in the accompanying drawings, wherein
Figure 1 is a section through a lense or vault light embodying my invention;
Figure 2 is a section through a modified form of my service;
Figure 3 is a section through a further modified form of my device;
Figures 4, 5, and 6 are sections through devices similar to those shown in
Figures 1, 2 and 3 and adapted to be used in places where the exposed surface
instead of being horizontal is at an angle to the horizontal.
Like letters refer to like parts throughout the several figures.
There is a number of vault lights, all of which are more or less adapted for the
use they are intended, and many of which, to some extent at least, accomplish the
purpose desired. Many of these devices have been provided with prisms, having
straight refracting or reflecting surfaces. These vault lights are ordinarily placed
so that their receiving surface is substantially in a horizontal plane and are so con-
structed that the light is thrown in lines approximating the horizontal. The rear
prisms, therefore, are obstructed by the prisms in front and a large amount of the
light is lost. The object of my invention is to form a device which will throw the
hight as nearly horizontal as practicable, and still allow it to pass by the prisms
without being obstructed thereby, thus avoiding the loss of light ordinarily occur-
rng. I have found that the device herein illustrated approaches this result as
near as it is practicable to do so. The several constructions herein shown all
approximate this result by similar means.
Referring now to Figure 1, which shows a body portion A provided with the pro-
jecting parts or prisms B, 1 have found that if the reflecting surface C is curved in
a manner similar to that shown, that is, if it is a convex curve, the rays of light
falling on the receiving surface D and passing through the prism will be reflected
and refracted so as to clear the prism next adjoining as shown, the rays of light
after leaving the prism being thrown in as nearly horizontal lines as is practicable.
The curve given to this surface depends, of course, upon the several conditions and
1, therefore, do not wish to limit myself to any particular curve, the only limita-
tion being that it shall be curved.
Referring now to Figure 2, I have shown a construction for obtaining the same
result when the reflecting surface C is straight. In this case the refracting sur-
face E is curved, such surface being given a convex curve as shown.
In Figure 3 I have shown a construction wherein two curved surfaces are used,
the reflecting surface and the refracting surface E both being curved. In this
construction both curves act to change the direction of the rays of light so as to
make them leave the prisms in as nearly horizontal lines as is practicable and
still have them pass below the adjoining prism or lense.
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page_text: In Figures 4, 5, and 61 have shown the devices illustrated in Figures 1, 2 and
3 modified so as to be adapted for alley lights or sky lights or other places where
the receiving surface is set at an oblique angle to the horizontal. The forms of
vault light herein shown are adapted to be used in positions where the receiving
surface D is in an approximately horizontal plane instead of a vertical plane, and
it will be seen that the desired result may be obtained when the projecting ribs
or prisms are provided with a curved refracting or reflecting plane or when both
these planes are curved.
I do not, of course, presume to have shown in the drawings all the possible forms
by which the result sought can be obtained, and indeed I have designed other
forms than those shown. The ideal device along the lines of my invention would
be one in which all of the rays of light entering, are received and directed for-
wardly so as to meet nearly approach without impinging upon the prisms in front.
Of course, this would be most desirable in such lights ás are called vault lights,.
though it is not material what the name or construction of the device may be other
than that it would be such as to accomplish the result above referred to.
I have spoken of my invention as a vault light; it is more correctly described
however as a Prism tile and I prefer to use that term.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I claim
...
1. A prism tile comprising a part with a substantially plane receiving surface
and a projecting prism having one curved surface, the curvature of such surface
and the character of the other prism surface being such that substantially all the
rays of light falling upon the receiving surface from a given direction will be so
treated successively by the prism surfaces as to be converged substantially along
a line a little farther below the plane of the receiving surface than the lower line
of such prism and in advance of the lower line of such prism by a distance about
equal to the greatest width of such prism in the direction in which the light is to
be thrown.
A prism tile comprising a part with a substantially plane receiving surface
and a projecting prism having one curved surface and one plane surface, the cur-
vature of such surface and the character of the other prism surface being such that
substantially all the rays of light falling upon the receiving surface from a given
direction will be so treated successively by the prism surfaces as to be converged
substantially along a line a little farther below the plane of the receiving surface
than the lower line of such prism and in advance of the lower line of such prism
by a distance about equal to the greatest width of such prism in the direction in
which the light is to be thrown.
3. A prism pavement comprising a series of prism tiles each having a receiv-
ing surface substantially parallel with the pavement surface and a downwardly
projecting prism which is provided with two surfaces transverse to the direction
in which the light is to be thrown, one of such surfaces being curved and the cur-
vature of that surface and the character of the other surface being such that sub-
stantially all the light received on the receiving surface from a given direction is
successively so treated by the prism surface as to be converged along a line just
below the lower line of the next preceding prism.
4. A prism tile comprising a part with a substantially plane receiving surface
and a projecting prism having one curved surface, the curvature of such surface
and the character of the other prism surface being such that part of the rays of
light falling upon the receiving surface from a given direction will be so treated
successively by the prism surfaces as to be converged substantially along a line a
little farther below the plane of the receiving surface than the lower line of such
prism and in advance of the lower line of such prism by a distance about equal
to the greatest width of such prism in the direction in which the light is to be
thrown, and the remainder of the rays will be directed into horizontal lines.

page_text: 5. A prism tile comprising a part with a substantially plane receiving surface
and a projecting prism having one curved surface and one plane surface, the cur-
vature of such surface and the character of the other prism surface being such that
part of the rays of light falling upon the receiving surface from a given direction
will be so treated successively by the prism surfaces as to be converged substan-
tially along a line a little farther below the plane of the receiving surface than
the lower line of such prism and in advance of the lower line of such prism by a
distance about equal to the greatest width of such prism in the direction in which
the light is to be thrown, and the remainder of the rays will be directed into
horizontal lines.
6. A prism pavement comprising a series of prism tiles each having a receiving
surface substantially parallel with the pavement surface and a downwardly projec-
ting prism which is provided with two surfaces transverse to the direction in which
the light is to be thrown, one of such surfaces being curved and the curvature of
that surface and the character of the other surface being such that part of the light
received on the receiving surface from a given direction is successively so treated
by the prism surface as to be converged along a line just below the lower line of
the next preceding prism, and the remainder of the light is directed into horizontal
lines.
7. A vault light or prism tile, as herein described operating as and for the
purpose specified.
F. WISE HOWORTH,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.