IMPROVEMENTS IN THE CONSTRUCTION OF SURVEYOR'S LEVELS AND OTHER SURVEYING INSTRU- MENTS
Year: 1863

page_text: LETTERS PATENT to Francis John Pastorelli, of 208, Piccadilly, in the
County of Middlesex, Optician, for the Invention of "IMPROVEMENTS IN
THE CONSTRUCTION OF SURVEYOR'S LEVELS AND OTHER SURVEYING INSTRU-
MENTS."
Sealed the 26th April 1864, and dated the 3rd November 1863.
PROVISIONAL. SPECIFICATION left by the said Francis John Pastorelli
at the Office of the Commissioners of Patents, with his Petition, on the
3rd November 1863.
I, FRANCIS JOHN PASTORELLI, of 208, Piccadilly, in the County of
Middlesex, Optician, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN THE CONSTRUCTION OF SURVEYOR'S LEVELS AND OTHER
SURVEYING INSTRUMENTS," to be as follows:-
The Invention consists in a new method of mounting levels and other
surveying instruments upon the ordinary tripod stand. The metal plate which
screws in the usual manner upon the cup of the tripod has at the centre of its
upper side a globular projection, which enters a socket of corresponding form
at the end of an upright stem, to the upper part of which stem the surveying
instrument is secured, but in such a manner as to rotate in a horizontal plane
in the usual way. The said stem and the instrument it carries resting upon
the globular projection (which with the socket at the end of the said stem

page_text: forms a ball-and-socket joint), may be inclined in any direction with the tripod
plate so as roughly to set the instrument by hand with the aid of the spirit levels
attached to it. In order, however, to adjust the instrument with the exactitude
required, as well as to firmly lock it in any desired position, the stem has
formed upon it an inverted cup, the exterior surface of which is globular and
concentric with the globular projection on the tripod plate. A second plate
or ring surrounds this inverted cup, the edge of the hole through the said
plate fitting the cup and forming a ball-and-socket joint, which allows the
said ring or plate to assume any position with regard to the axis of the stem.
This ring or plate, when firmly pressed upon the inverted cup on the stem,
holds the said stem and the instrument it carries in any desired position.
The binding or locking of the said ring or plate is arranged in the following
manner-The ring has three or four holes formed near its edge, and at
equal distances apart, these holes being countersunk on the upper side,
such countersink being globular; milled-headed screws having globular
projections formed upon them under the milled-heads pass through the
holes in the ring or plate, the globular projections of the screws working
into the countersunk holes of the ring or plate. The ends of the screws
work in nuts, which also have globular projections working into corres-
ponding cups formed in separate blocks screwed upon the upper side of the
tripod plate. By turning these screws the ring or plate through which
the screws pass is forced down upon the exterior surface of the inverted cup
on the stem carrying the instrument, thus fixing the instrument, and at the
same time accurately adjusting it so as to rotate in a perfectly horizontal
plane. By turning the said screws the ring or plate is inclined more or less
with respect to the tripod plate, and carries with it the stem and instrument
attached to it. In order that the adjustment of the instrument by one pair of
screws (4 being used), may not be thrown out by the adjustment of the
instrument by the other pair of screws, it is necessary that the centres of the
globe ends of the nuts in which the screws work should all be in the same
plane with the globular projection in the centre of the tripod plate. In order
to prevent the clamping ring or plate rotating in a horizontal plane inde-
pendently of the tripod plate a stud may be attached to the tripod plate, which
may pass through a hole formed in the ring or clamping plate, such hole not
being cylindrical but countersunk on one or both sides, thus allowing of the
free motion of the said clamping plate except in a horizontal direction. A
tube is fitted to the exterior edge of the clamping plate, which projects down-
wards over the tripod plate so as to exclude dust.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Francis John Pastorelli in the Great Seal Patent Office on
the 3rd May 1864..
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FRANCIS
JOHN PASTORELLI, of 208, Piccadilly, in the County of Middlesex, Optician,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Third day of November, in the year of our Lord
One thousand eight hundred and sixty-three, in the twenty-sixth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto me,.
the said Francis John Pastorelli, Her special licence that I, the said Francis
John Pastorelli, my executors, administrators, and assigns, or such others as I,
the said Francis John Pastorelli, my executors, administrators, and assigns,
should at any time agree with, and no others, from time to time and at all times
thereafter during the term therein expressed, should and lawfully might make,
use, exercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for "IMPROVE-
MENTS IN THE CONSTRUCTION OF SURVEYOR'S LEVELS AND OTHER SURVEYING
INSTRUMENTS," upon the condition (amongst others) that I, the said Francis
John Pastorelli, my executors or administrators, by an instrument in
writing under my, or their, or one of their bands and seal, should parti-
cularly describe and ascertain the nature of the said Invention, and in
what manner the same was to be performed, and cause the same to be
filed in the Great Seal Patent Office within six calendar months next and
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Francis John Pastorelli, do hereby
declare the nature of my said 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 consists in a new method of mounting levels and other
surveying instruments upon the tripod stand. The metal plate which screws
upon the tripod cap has at the centre of its upper side a globular projection,
which enters a socket at the end of an upright stem, to which the surveying.
instrument is secured, but in such manner as to rotate in a horizontal plane.
in the usual way. The said stem and instrument it carries rest upon the
globular projection forming a ball-&-socket joint, and may be inclined in any
direction with the tripod plate, so as roughly to set the instrument by hand;
with the aid of the spirit levels. To adjust the instrument with exactitude, a

page_text: well as to firmly lock it, the stem has formed upon it an inverted cup, the
exterior of which is globular & concentric with the globular projection on the
tripod plate. A second plate or ring surrounds this inverted cup, the edge of
the hole through the said plate fitting the cup & forming a ball-and-socket
joint, which allows the said ring or plate to assume any position with regard
to the axis of the stem. This ring or plate, when firmly pressed upon the
inverted cup, holds it & the stem & instrument in any desired position. The
binding or locking of the said ring or plate is arranged in the following
manner-The ring has three or four holes formed near its edge and at
equal distances apart; these holes are countersunk on the upper side in a
globular form. Milled-headed screws having globular projections attached to
them, or made separately as hereafter described, pass through the holes in the
ring or plate, the globular projections under the milled heads of the screws
working in the countersunk holes. The ends of the milled-headed screws
work in nuts, which also have globular projections working in corresponding
cups formed in separate blocks screwed upon the upper side of the tripod
plate. By turning these screws the plate through which they pass is forced
down upon the exterior surface of the inverted cup on the stem carrying the
instrument, allowing the latter to be adjusted so as to rotate in a horizontal
plane. In order that the adjustment of the instrument may not be thrown
out by one pair of screws, after the first pair (when four are used) have been
set, it is necessary that the centres of the globe ends of the nuts in which the
screws work should all be in the same plane with the globular projection in
the centre of the tripod plate. To prevent the clamping ring or plate from
rotating in a horizontal plane independently of the tripod plate, a stud may be
attached to the tripod plate, which may pass through a hole formed in the
ring or clamping plate, such hole not being cylindrical but countersunk on
one or both sides, thus allowing of the free motion of the said plate except in
the horizontal direction. A tube may be fitted to the exterior edge of the
clamping plate, projecting downwards over the tripod plate so as to exclude
dust.
Having stated the nature of my Invention, I will now proceed more fully to
describe the manner of performing the same, reference being made to the
accompanying illustrations, which shew a practical way of the said Invention
being carried out.
Fig. 1 shews an elevation, partly in section, of my Invention as applied to a
surveyor's level. A is the lower parallel plate screwed upon the tripod head;
B is the ball joint in centre of said plate, the end of the stem C being cupped
to correspond with the projection on the plate. The instrument revolves on

page_text: the stem C in the usual way; D is an inverted cup, cast with the stem or axis
C, and upon which inverted cup the upper parallel plate presses; F, F, are
the clamping screws, having milled heads at their upper ends and globular
projections formed with them, or made separately as shewn in Fig. 2, at H;
these projections work in the upper parallel plate or ring, and the lower ends
of the said screws work in the movable nuts G, each of which forms a ball-
&-socket joint. There may be three or four of these clamping or milled-
headed screws. The movable nuts are carried by the lower parallel plate A.
The cup D is concentric with the ball-&-socket joint B, and this & the
ball-&-sockets of the nuts G are in the same geometrical plane. When the
globular projection under the milled-head screw heads are made separately, as
in Fig. 2, small recesses are turned both in the under side of the milled heads
and also in the upper or flat side of the globe pieces H, so that a small spring
may be introduced between them. In the Figure this spring is shewn com-
pressed. Its object is to prevent the falling or inclination of the instrument
on one side when the clamping screws are loosened, the friction between the
inverted cup & the parallel plate E not being sufficient to retain the level
in an upright position. The small spirial springs slightly increases this fric-
tion within small limits, & so prevent the falling over of the instrument,
although they in no way impede the tightening up of the screws & the firm
clamping of the plate E upon the inverted cup D.
In witness whereof, I, the said Francis John Pastorelli, have hereunto.
set my hand and seal, this Third day of May, in the year of our Lord
One thousand eight hundred and sixty-four.
F. J. PASTORELLI. (L.S.)