Year: 1886

page_text: Date of Application, 25th Oct., 1886.
Complete Left, 20th July, 1887.
Complete Accepted, 9th Sept., 1887.
I, ALFRED WALTER DOLLOND, of 66 Hurlingham Road, Fulham, in the County of
Middlesex, Clerk do hereby declare the nature of this invention to be as follows:-
My invention relates to tripod stands for supporting Photographic Cameras, or
Scientific Instruments. For convenience in use such stands may have legs adjustable
to various lengths. I make the upper portion of the legs of my stand in any of the
forms usually found convenient. I prefer those forms in which the upper portion of
the legs consists of two rods or laths, formed at the top so as to engage with the
tripod top. At the lower end of the upper portion of the legs I fix a block pierced
with a hole through which the lowest length of the legs slides up into or beside the
upper portion. In order that the legs may be conveniently fixed at the required
height, I make the lower or sliding portion of the legs in my stand of rods of a
spiral, curved, or snail shape in section; that is of a form such that, as the leg is turned
completely round on its axis, the outer surface continually recedes from that axis.
I make the hole in the block, through which the leg slides, of a corresponding shape,
and of such size that the leg may slide easily through it.
While the leg slides in the hole in such a position that the form of the leg and
that of the hole correspond, the leg may be slid up through the block, or drawn out,
very readily. When however the leg is revolved on its axis, so that the most
projecting portion of the leg encounters the decreasing surface of the hole, it jains
and becomes fast.
Therefore, in use, the sliding portion of the leg is withdrawn to the required
extent, and then partially revolved on its axis until it becomes fixed with a firmness
corresponding to the amount of force employed in revolving it.
The leg is unfixed by revolving it in the opposite direction, and may then be
easily slid completely into the upper portion and is ready for carriage.

page_text: The sliding rods of the form described may be applied so as to form the lower
part of the legs of stands with several folds.
The legs may, if required, be made of metal tubing of a form so that one portion
slides within another, provided that the tubing is of the curved, or spiral form
described.
The legs may be made of wood, metal, or other suitable substance, or of a
combination of substances.
1000
COMPLETE SPECIFICATION.
Improvements in Tripod Camera Stands.
I, ALFRED WALTER DOLLOND of 66 Hurlingham Road, Fulham, London, in the
County of Middlesex, Clerk, 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 to tripod stands for supporting Photographic Cameras or
Scientific Instruments. My invention may be employed with that form of leg in
which one part is arranged to slide within or beside another.
The sliding part in my stand leg consists of a rod or tube of a spiral, curved, or
snail shape in section, as shown in Fig. I A. This rod is arranged so as to slide
through a block pierced with a hole of a shape corresponding to the shape of the rod
but rather larger to allow free movement, as shown by the aperture in B, Fig. I.
When the rod is held in such a position that its shape corresponds to that of the hole,
as in Fig. I, it will slide very readily. But when it is rotated on its axis with some
force in the direction shown by the arrow in Fig. II, it jams very tightly and will
remain fixed during use. It may be instantly released by being rotated in the opposite
direction, and then slides as may be required.
The block through which the sliding portion of the leg passes may be attached to
the other portions of the leg in any convenient manner.
The block may be of any convenient external form, and may be in more than one
part, provided that the hole through it be substantially of the form indicated.
In Fig. III 1 show a side view of a block b, b, attached to the upper portions c, c, of
a leg of a stand of a common form. The rod a, a, in this case, when loosened will

page_text: slide up between the upper side pieces of the legs c, c, for convenience of carriage, or
for adjusting the length of the leg.
In use the sliding leg is held in the position indicated by Fig. I and slid in or out
as may be required. It is fixed or unfixed by rotation as before described. Springs
or catches may be introduced to afford additional security if required.
The legs may be made of metal tubing adjustable by telescopic action, provided
that the sliding portion is of the curved or spiral form described.
My invention does not relate to the general arrangements of stand legs, or to the
means of attaching the legs to the top of the stand.
Having now particularly described and ascertained the nature of my said Invention,
and in what manner the same is to be performed, I declare that what I claim is:
I. The employment of sliding portions of tripod legs of the shape herein described
and indicated or of any mere modification of such shape.
II. The arrangement whereby legs of such shape slide through holes of a
corresponding or nearly corresponding shape, substantially as described and
indicated.
III. The method of fixing and unfixing sliding portions of the shape described
when extended to the required length substantially as described and indicated.
Dated this 20th day of July 1887.