Improvements relating to Frameless Spectacles and Eye-glasses.
Year: 1896

page_text: Date of Application, 24th Dec., 1896-Accepted, 13th Mar., 1897
COMPLETE SPECIFICATION.
Improvements relating to Frameless Spectacles and Eye-glasses.
We, WALTER SCOTT ESSICK, Machinist, WILLIAM WALLACE ESSIOK, Manufacturer,
HENRY FEINSTEIN, Salesman, all of Reading, Pennyslvania, U.S.A. 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:-
Our invention relates to frameless spectacles and eye glasses and particularly to
the manner of attaching the necessary fittings to the frameless lenses.
These fittings are commonly secured to the lenses by means of clamping screws or
rivets each of which passes through a perforation in the lens and engages a
correspondingly perforated clamping ear or ears which form part of the fittings
whother the latter be arranged for use as a nose piece connection, a temple connection,
or a handle. These ears, aud the fittings of which they form a part, are commonly
made of metal, and the inner face of each ear is drawn tightly into.contact with
the surface of the lens hy the clamping screw. In practice this necessitates, vory
careful workmanship to avoid so straining the lens on the one hand, as to cause it
to crack either in the act of clamping the fitting to it or thereafter in the ordinary
handling of the finished article; and on the other hand to avoid a looseness of
connection which is very unsatisfactory. The purpose of our invention is to
overcome these difficulties; that is to enable the fitting ears to be clamped against
the surface of a lens with any desirable amount of pressure not only without danger
of straining or cracking the lens but so as to overcome the weakness naturally caused
by the perforation provided for the passage of the clamping screw; which form of
connection for the fittings is generally used notwithstanding the resulting difficulties
above referred to.
In Figure 1 of the accompanying drawing we have indicated an ordinary fitting
as commonly attached to a frameless lens, the latter being shown of plano-convex
form. It will at once be noticed that the oar a which contacts with the convex fuce
of the lens necessarily bears on the edge of the perforation in the lens so that when
the clamping screw c is drawn up practically the whole strain comes at its point of
greatest weakness thus tending to start a fracture even when only a moderate
clamping pressure is brought upon it. But it is also evident that this clamping
pressure is brought to bear at the most ineffective point for firmly attaching the
fitting to the lens being as near as possible to the centre on which the fitting tends
to turn and thus causing any strain upon the projecting portion of the fitting to act
at a considerable leverage, and necessitating a correspondingly greater clamping
pressure with the accompanying increased likelihood of breakage. In the case of
the ear b, contacting with a flat lens surface, the likelihood of breakage being caused
by the clamping pressure is much less, yet there is no certainty that this pressure will
be evenly distributed over the lens surface covered by the ear, and any inequality
will tend to cause a fracture; moreover even if it were fairly distributed over the
whole surface it would not be as effective in firmly clamping the parts as we now
find it possible to make it.
Having long experienced these difficulties in connection with this universally used
form of fitting we finally conceived the idea that to avoid them, that portion of the
lens surface immediately around the perforation should be entirely freed from the

page_text: clamping pressure, and that the latter should be distributed as evenly as possible.
around said perforation at as great a distance therefrom as is practicable. To meet
the requirements thus theoretically determined upon we have changed the form of
the contacting face of the ears as indicated in Figures 2 and 8.
Figure 2 is a longitudinal section of a fitting embodying our improvements, shown
attached to a lens ; and Figure.3. is a sectional plan view of the fitting on the line a
of Figure 2.
The clamping ear d is of ordinary size and is connected with the body D of the
fitting as usual by an arm g, which latter however we preferably reduce in thickness
so as to make it sufficiently yielding in the plane of the clamping screw to permit
the clamping ear to properly adjust itself to the surface of the lens as hereafter
described. In order to insure proper contact with the surface of the lens as already
explained we provide the inner face of the clamping ear with an outer bearing f
at a distance from the perforation for the screw c, and with that portion of the lens
immediately surrounding the perforation therein for the passage of the clamping
screw c, no matter what the shape of the lens. This outer bearing is preferably,
reduced to a sufficiently thin edge to permit of the metal being slightly bent or
crushed by the clamping pressure so as to make it conform exactly to the lens
surface, thereby insuring an unbroken line of contact around the hole; and this.
result is facilitated by the yielding connection g between the ear and the body of.
the fitting, which allows the bearing ring f to be drawn down evenly all around even
though it is not properly set to the lens before the clamping screw is tightened up,
as indicated in Figure 2 (see lower ear).
The necessary strength is given to this connection by making it relatively wide,
thus combining ample rigidity with the capacity to yield in the plane of the screw.
for the purpose described.
The effect of this improved construction is important both in facilitating the
operation of attaching the fitting and in rendering the connection more firm and
safe. The lens is freed from all contact with the fitting adjacent to the perforation,
and the clamping pressure on the bearing f may be increased to any possible
extent without injury to the lens such pressure on the contrary positively preventing.
breakage of the lens through the perforation, which has been heretofore the great
source of weakness in this class of spectacles. Moreover the effectiveness of the
clamping pressure, as well as the amount of pressure which it is safe to apply, is
so greatly increased that the straps h which are ordinarily employed to prevent
turning of the fitting may be dispensed with if desired.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we'
claim is :-
1. A perforated spectacle lens having a fitting clamped thereto by means of a
clamping screw engaging a perforated ear of said fitting, the inner face of which
ear is recessed to form an outer bearing against the lens and to leave a portion of
the lens immediately surrounding the perforation free from pressure, substantially as
and for the purpose set forth.
2. A fitting for a perforated spectacle lons having a perforated clamping ear and
an outer bearing formed on the inner face of said ear and adapted to set against the
surface of the lens at a distance from the perforation in the latter substantially as
and for the purpose set forth.
3. A fitting for a perforated spectacle lens having a perforated clamping ear
recessed on its inner face so as to form an outer edge of inetal adapted to contact
with the face of the lens and to conform to the latter under clamping pressure,
substantially as and for the purpose set forth.
4. A fitting for a perforated spectacle lens having a perforated clamping ear with
an outer bearing formed on the inner face thereof and adapted to set against the
surface of the lens at a distance from the perforation in the latter and a yielding

page_text: connection substantially as described between said ear and the body of the fitting
adapted to permit adjustment of the ear to its seat upon theilens under pressure of
the clamping screw substantially and for the purpose set forth.
Dated this 24th day of December 1896.
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents.