Improvements in or relating to Globes or Protectors for Electric and other Lighting Apparatus.
Year: 1899

page_text: Date of Application, 1st May, 1899
Comalada Cannifontina Laft
3000
4716
000
PROVISIONAL SPECIFICATION.
Improvements in or relating to Globes or Protectors for Electric and
other Lighting Apparatus.
We, JAMES GRAY PENNYCUICK, of 302, Wellington Street West, Sanitary
Engineer and FREDERIC WILLIAM BARRETT, of 48. Yorkville Avenue, Lucical
Engineer, both in the City of Toronto, in the County of York and Province of
Ontario, Canada, do hereby declare the nature of this invention to be as follows:-
The object of our invention is to devise a globe or envelope for electric and
other lamps, which will so deflect the light from the lamp as to give an increased
field of illumination of equal intensity at all points in any given plane at right
angles to the axis of the cone, and it consists, essentially, in forming upon the globe
a series of external prisms above and below a neutral line, the prisms above the
neutral line being adapted to deflect incident rays from the centre of illumination
to or below the horizontal, and the prisms below the neutral line to deflect incident
rays up towards the horizontal, the whole being constructed in detail substantially
as hereinafter more specifically described.
Under ordinary circumstances a large percentage of the light rays given off by
a lamp travel upward, and are lost in the air without in any way being effective
for illuminating the ground, or other surface beneath the lamp. There is also
a zone or circle of intense light thrown downward in the immediate vicinity of
the lamp, so that a small area receives an excessive amount of light, particularly
in the case of a strong light like an electric-are lamp very dazzling to the eye.
while at a distance the light soon becomes deficient. We obviate this difficulty
by so constructing prisms at the upper portion of our globe, that they will inter-
cept the upwardly travelling rays and deflect them downward so that they will,
after leaving the outer surface of the globe, travel in a direction slightly inclined
below the plane of the source of light in the lamp: further by means of the
prisms in the lower section of the glohe, we intercept the intense band of light
travelling downward from the lamp, and so refract and deflect it upward that a
large proportion will, after leaving the outer surface of the globe, travel in a
direction more nearly horizontal to the plane of the source of light. The result
of this double action in the upper and lower sections of the globe. is to vastly
increase the field of illumination of a lamp, and to produce a cone of illumination
of equal intensity at all points in any given plane at right angles to the axis of
the cone.
There is usually a circle below the lamp deficient in illumination owing to
the shadows cast from its base. To illuminate this circle we form at the bottom
of the globe a series of prisms intended to divert the light incident upon them
inward towards the perpendicular, so destroying the shadows.
Dated this 1st day of May 1899.
BOULT & WADE.
Agents for the Applicants.

page_text: Improvements in or relating to Globes or Frotectors for Electric and
other Lighting Apparatus.
We, JAMES GRAY PENNYCCK, formerly of 302, Wellington Street West, but
now of Cor. Binscarth and Glen Roads, Sanitary Engineer, and FREDERIC WILLIAM
BARRETT, of 48, Yorkville Avenue, Lucical Engineer, both of the City of Toronto,
County of York and Province of Ontario, Canada, do hereby declare the nature of
this invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
The abject of our invention is to devise a globe or envelop for electric and
other lamps which will so deffect the light from the lamp as to give an increased
field of illumination and produce a cone of illumination of equal intensity at all
points in any given plane at right angles to the axis of the cone; and it consists,
essentially, in forming upon the globe a series of external prisms above and below
a neutral line, the prisms above the neutral line being adapted to deflect incident
rays from the centre of illumination towards the horizontal and the prisms below
the neutral line in deflect incident rays outwardly towards the horizontal, the
whole being constructed in detail substantially as hereinafter more specifically
described and then definitely claimed.
The drawing represents a cross-section of one-half of a lamp-globe constructed
in accordance with our invention.
Indre ordinary circumstances a large percentage of the light-rays given off by
a lamp travel upward and are lost in the air without in any way being effective
for illuminating the ground, or other surface beneath the lamp. There is also
a zone or circle of intense light thrown downward in the immediate vicinity of
the lamp, so that a small area receives an excessive amount of light, particularly
in the case of a strong light like an electric-are lamp, very dazzling to the eye.
while at a distance the light soon becomes deficient. We obviate this difficulty
by so constructing prisms at the upper portion of our globe that they will inter-
cept the upwardly-traveling rays and deflect them downward, so that they will.
after leaving the outer surface of the globe, travel in a direction slightly inclined
below the plane of the source of light in the lamp. Further, by means of the
prisms in the lower section of the globe we intercept the intense band of light
traveling downward from the lamp and so refract and deflect it upward that a
large proportion will, after leaving the outer surface of the globe, travel in a
direction more nearly horizontal to the plane of the source of light. The result
of this double action in the upper and lower sections of the globe is to vastly
increase the field of illumination of a lamp and to produce a cone of illumination
of more equal intensity at all points in any given plane at right angles to the
axis of the cone than is given by a bare light.
There is usually a circle below the lamp deficient in illumination owing to
the shadows cast from its base. To illuminate this circle, we form at the bottom
of the globe a series of prisms intended to divert the light incident upon them
inward toward the vertical, so destroying the shadows.
Referring to the drawing, A represents the centre of illumination, which may
be taken as the average position of the are in an electric-are light.
Bis the globe, having a series of annular prisms formed upon its outer surface.
These prisms are formed in four sets C. D. E, and F. The upper sets of prisms
are adapted to deflect the upwardly-traveling rays from the centre of illumination
and bend them downward toward the horizontal. With the extreme uppermost
prisms C total internal reflection will occur, which effects the same result as the

page_text: refraction occurring in the prisms 1. The upper middle set of prisms 1) refract
or divert the light incident thereon downward and outwardly in a direction more
nearly horizontal than when emergent from the centre of illumination. The set
of prisms E refract the incident light-rays in an upward direction, so that they
travel outwardly to a much greater distance than would be reached by the path
taken by the downward rays: The set of prisms Fare adapted to bend the rays
of light incident thereon in toward the vertical, and thus illuminate the circle
directly below the lamp. It will be noted that the refracting-surfaces and a
of each prism are, as far as possible, varied in angle according to their position
with regard to the centre of illumination, so that the light incident upon them
may be directed to the proper place to send the greatest volume of light in the
direction required and so produce the equality of illumination aimed at. It will
further be noted that the inactive surfaces of the prisms are set at such an angle
that at any given point the surface of any given face is coincident or parallel
with the path in the glass which the incident ray falling upon the prism from the
centre of illumination will take when deflected by the refractive effect of the glass
in passing through it. In regard to said inactive surfaces of the prisms just
referred to, we may state. further, that as soon as a ray of light strikes the curved
inner surface of the globe its path is deflected, and if the surfaces & were set at
an angle to this path the light on striking the surfaces would either be refracted
or reflected, according to the angles at which they were set. It is therefore essen-
tial if these surfaces be inactive that they be parallel to the path of the ray of
light through the glass of the globe at the point at which they are set. Thus these
surfaces neither intercept nor divert any of the light from the source
illumination.
of
The globe is preferably circular in horizontal section, though polygonal or other
forms might be adopted. In vertical section the globe may also be varied in
shape to suit the source of illumination with which it is to be used.
It must be remembered that in all cases the internal surface of the globe forms
one of the refracting sides of each prism, so that the curvature of the globe is
such as to give with the angle of the outer refracting-surface of each prism the
proper degree of refraction.
Although we use the words "much more equal intensity." it would be correct
to say "equal intensity" if the cone of illumination were made small and the
prisms correctly calculated and distributed.
Having now particularly described and ascertained the nature of this said
invention, and in what manner the same is to be performed, we declare that what
we claim is :-
1. A glass lamp globe or envelop having a series of external horizontal prisms
formed thereon, each having at least two active surfaces. the angle between the
active surfaces of the prisms being varied according to the position a particular
prism may occupy with regard to the centre of illumination and according to the
curvature of the vertical section of the globe. the angles being arranged to pro-
duce a cone of illumination of much more equal intensity than is given by a bare
light, substantially as and for the purpose specified.
2. A glass lamp globe or envelop having a series of external horizontal prisms
formed thereon, each having at least two active surfaces and one neutral surface set
at such an angle that it is coincident with or parallel to the path in the glass which
an incident ray falling on the prism from the centre of illumination will take
when deflected by the refractive effect of the prism, the angle between the active
surfaces of the prisms being varied according to the position a particular prism
may occupy with regard to the centre of illumination and according to the curva-
ture of the vertical section of the globe, the angles being arranged to produce
a cone of illumination of much more equal intensity than is given by a bare light,
substantially as and for the purpose specified.
8. A lamp globe or envelop having a series of external horizontal prisms formed

page_text: thereon in three sets, the upper set being adapted to deflect incident rays from the
centre of illumination toward the horizontal, the middle set to deflect incident rays
outwardly toward the horizontal and the lower set to deflect incident rays down
toward the vertical, so as to produce a cone of illumination of much more equal
intensity at all points in any given plane at right angles to the axis of the come
than is given by a bare light, substantially as and for the purpose specified.
4.A glass lamp globe or envelop having a series of external horizontal prisms
formed thereon above and below a neutral line, the prisms above the neutral lino
being adapted to deflect incident rays from the centre of illumination toward the
horizontal, and the prisms below the neutral line to deflect incident rays outwardly
Toward the horizontal, each prism having one face coincident at any given point
with a line parallel to the path of the glass which an incident ray will take when
deflected by the refractive effect of the glass prism, the angle between the active
surfaces of the prisms being varied according to the position a particular prism
may occupy with regard to the centre of illumination and according to the curva-
ture of the vertical section of the globe, the angles being arranged to produce
cone of illumination of much more equal intensity than is given by a bare light,
substantially as and for the purpose specified.
A glass lamp globe or envelop having a series of external prisms formed
thereon above and below a neutral line, the prisms above the neutral line being
adapted to deflect incident rays from the centre of illumination toward the hori
zontal, and the prisms below the neutral line to deflect incident rays toward the
horizontal. the active surfaces of the prisms being varied in angle according to
their position with regard to the centre of illumination, the effect of the varying
prisms being to produce a cone of illumination of much more equal intensity at
all points in any given plane at right angles to the axis of the cone than is given
by a bare light, substantially as and for the purpose specified.
Dated this 4th day of January 1900.
BOULT, WADE & KILBURN,
Agents for the Applicants.