Improvements in the Method of Mounting Photographic and other Lenses.
Year: 1889

page_text: Date of Application, 3rd Aug., 1889-Accepted, 19th Oct., 1889
COMPLETE SPECIFICATION.
Improvements in the Method of Mounting Photographic and other
Lenses.
I, DAVID WILLIAM NOAKES of 9 Billingsgate Street, Greenwich in the county of
Kent, Manufacturing Optician 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 :-
My invention relates more especially to double or combination lenses where the
stops or diaphragms or exposure shutters are introduced between the lenses-
Hitherto most lenses fitted with a series of stops or diaphragms have been so mounted
that the stops have been introduced between the lenses by means of a slot cut in the
len's mount, with the consequent tendency of the light to leak in to the interior of
the lens Again when exposure shutters are used especially those working between
the lenses and without means of adjustment so as to reduce or enlarge the extent of
their opening, there has been difficulty in limiting the aperture of the lens to the
intensity ratio required-To obviate these and other defects I mount one or more of
the lenses of the combination (preferably the front lens or lenses) in a distinct and
separate tube marked A in the drawing Fig. 1., this is made to fit the outer or
jacket tube B in such a manner as to withdraw easily, a stop of the largest aperture
intended to be used is fixed at C-Other stops of varying intensity ratios are easily
introduced by withdrawing the tube A and inserting a stop of the character & shape
of C Fig. 2. and then replacing tube A in its working position.
The same procedure is also adopted to introduce the stops when an exposure
shutter is fixed to the body of the mount or to the front lens, thus enabling any of a
series of stops to be instantly introduced without displacing the shutter.
When the lenses are of a large or heavy character, in order to make the inner
tube A fit the outer tube B in such a manner that the inner tube cannot slip out by
means of its own weight or being inaccurately fitted, I mount on the outer tube B.
Fig. 3. a divided brass band having two ears or lugs which are drawn together by
means of a screw, the outer tube B being slotted in several places to admit of sufficient
contraction.
Or in some cases I fit on the inner tube A a small stud which engages in a bayonet
joint cut in the outer tube B as shown at Fig. 4.
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 is
1st. The method of mounting one or more lenses of a double or combination lens,
in an inner tube that can he withdrawn and replaced readily, substantially as and
for the purposes set forth.
2nd. The mode of tightening the outer tube by means of a slit band & set screw
substantially as here set forth.
3rd. The mode of locking the inner to the outer tube by means of a pin engaging
in a bayonet slot substantially as here set forth.
Dated this Second day of August 1889.
DA
LUULADI
NOAK
KES.