Prismatic Daylight Reflectors and Pavement Lights, each Prism having a Curved Surface.
Year: 1897

page_text: Date of Application, 13th July, 1897-Accepted, 28th Aug., 1897
COMPLETE SPECIFICATION.
Prismatic Daylight Reflectors and Pavement Lights, each Prism
having a Curved Surface.
I, JOHN MEIGGS EWEN, of No. 1129 The Rookery, Chicago, County of Cook,
State of Illinois, United States of America, Mechanical Engineer, do hereby declare
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 prism lights for receiving and directing light into a
room or apartment to be lighted, and has for its object to provide a form of prism
light which, when placed at an inclination to the vertical, will receive and
transmit all the light falling upon its receiving surface from a given direction
through the prisms to the other side in such manner that such light will be
partly thrown into substantially horizontal lines and the remainder will be con-
verged on a line a little farther from 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, but parallel to the plane receiving surface.
My invention is illustrated in the accompanying drawings, wherein
Figure 1 is a view of my prism plate, each prism having one plane surface
and one curved surface.
Figure 2 is a similar view in which the plane and curved surfaces are reversed.
Figure 3 is an enlarged view of the prisms of Figure 1, and
Figure 4 is an enlarged view of the prisms of Figure 2.
Figure 5 is an enlarged sectional view of a canopy provided with a series of
these prisms, thus illustrating their use and operation.
Doubtless there may be other forms of these prisms and both surfaces may
be curved so as to get the desired result without departing from the spirit of
my invention.
A is the body of the prism light having a receiving surface D and the prisms B B
each having a lower surface C and an upper surface E.
In Figures 1 and 3 the upper surface E is plane and in Figures 2 and 4 the
upper surface is curved. The passage of the light through these prisms is
indicated by the dotted lines, a small quantity of light being converged on a
line below the upper prism in Figure 3 and a considerable quantity of light
being converged on each line in Figure 4.
E is a canopy frame containing a set of my prisms and it is preferably hinged
at F to the window frame G.
This form of prism light is peculiarly adapted for canopies and the like, the
light being received from above and being thrown by the canopy through an
opening beneath into the room to be lighted. Of course it is applicable to light
a room of which it forms in part the inclined roof or 'cover, such as in various
forms of sky-light work.
There are various forms of prism lights which may be placed vertically in
a window and which will then project the light into the room in substantially
horizontal lines. If such prism lights be inclined, as indicated in the drawing,

page_text: they may still throw some light received from a certain direction into the room,
but they will throw a certain amount of light against the preceding prism, and
in the case of prism lights intended only to operate by refraction other difficulties
and disadvantages arise if they are attempted to be used in a sharply inclined
plane.
I have spoken of my improvement as a prism light, of course it is evident
that the invention may be applicable to a set or series of prisms not made integral
with each other, as is the case with prism lights as that term is ordinarily used;
and moreover, if desired, the invention can be incorporated in a series of parts
more closely approximating what is known as prism tiles, such as are used for
pavements and the like.
Having now particularly described and ascertained the nature of the said in-
vention and in what manner the same is to be performed, I declare that what I
claim is:-
1. A prism light for canopies having the prisms with sides shaped substantially
as described and for the purpose specified.
2. A canopy prism light consisting of a frame and a series of prism tiles of
the shape as shown and specified placed in such frame to form a canopy light.
Dated this 13th day of July 1897.
For the Applicant,
W. LLOYD WISE,
46 Lincoln's Inn Fields, London, W.C., Chartered Patent Agent.