Improvements in Means or Apparatus for Supporting and Adjusting the Level of Surveyors' Levels, or other Scientific Instruments.
Year: 1893

page_text: Date of Application, 28th June, 1893
Complete Specification Left, 27th Mar., 1894-Accepted, 5th May, 1894
PROVISIONAL SPECIFICATION.
Improvements in Means or Apparatus for Supporting and Adjusting
the Level of Surveyors' Levels, or other Scientific Instruments.
I, FLETCHER FRANCIS SHERIDAN KELSEY of 9 Grosvenor Place in the City
of Bath and County of Somerset Civil Engineer, do hereby declare the nature of
this invention to be as follows:-
This invention relates to means or apparatus for supporting surveyor's levels
or other scientific instruments and for use in adjusting the level of such instruments
in use with rapidity.
In carrying out my invention I employ the following devices which I will for the
sake of illustration describe as applied to an ordinary dumpy level that is to
say I provide the ordinary hinged legs or other legs which are pivotted to a
platform.
The instrument is removable affixed in use to a stem from a ball, as by a screwed
sleeve taking on to a screwed stem, and this ball rests in a socket supported or
formed in the platform. The form of socket I prefer consists of three or other
number of antifriction wheels, rollers or balls.
The ball above its seat is held in place by a ring plate which is fixed by a clamp
and screw stem or it may be by a fly nut or other similar device may be locked to
the platform and so jam the ball in the socket and hold it tightly when so
required.
66
"
Pendent from and rigidly fixed in the ball at its upper end is a rod which at its
lower end carries (removably) a plumb, bob or weight so that the stem is by
gravity kept upright and the instrument supported by it approximately level.
For finer, or final adjustment I provide on the lower part of the instrument and
between it and the connection to the stem a hinged connection consisting of two
plates preferably wedge formed centred together at the ends having the greater
diameter and having the approach of their opposite ends regulated and secured in
assigned position by a suitably formed regulating screw bolt and socket, the bolt
being operated by a fly or like hold or a single wedged piece hinged to the ordinary
base of the instrument may be similarly adjusted.
By means of a small mirror placed at an angle of 45° at one end of the spirit
level attached to the telescope the surveyor can (without removing his eye from
the eye-piece) see that the telescope is perfectly level at the moment when he takes
his reading on the staff.
For packing and carriage I prefer to form on the inside of each leg a suitably
shaped shoe or part into which a part of the weight of the rod may lie and when
the legs are drawn together the weight will be encompassed by these parts and by
the aid of catches on the parts the whole may be securely locked together.
Although I have described the invention in connection with a dumpy level it is
also applicable to other mathematical and scientific instruments in which accuracy
of level is essential.
09th day of June 1802

page_text: COMPLETE SPECIFICATION.
Improvements in Means or Apparatus for Supporting and Adjusting
the Level of Surveyors' Levels, or other Scientific Instruments.
I FLETCHER FRANCIS SHERIDAN KELSEY of 9 Grosvenor Place in the City
of Bath and County of Somerset, Civil Engineer, 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 :-
This invention relates to means or apparatus for supporting surveyor's levels or
other scientific instruments and for use in adjusting the level of such instruments in
use with rapidity.
In carrying out my invention I employ the following devices which I will for the
sake of illustration describe as applied to an ordinary dumpy level that is to say I
provide the ordinary hinged legs or other legs which are pivoted to a platform.
The portion of the instrument requiring adjustment is, when in use, affixed at
right angles to the end of a rod passed through the centre of a ball, a sufficient
length of the rod projecting beyond the ball to admit of the aforesaid portion being
firmly screwed to it and this ball rests in a socket supported or formed in the
platform.
The form of socket I prefer consists of three or other number of antifriction
wheels, rollers or balls.
To the lower end of the rod a bob or plumb weight (removable) is attached so
that the rod is by gravity kept perpendicular and the telescope at right angles to it
approximately level. The ball above its seat is held in place by a hinged ring
plate which is fixed by a clamp and screw stem or it may be by a fly nut or other
similar device may be locked to the platform and so jam the ball in the socket and
hold it tightly.
For finer or final adjustment I provide on the lower part of the instrument and
between it and the connection to the rod a hinged connection consisting of two
plates preferably wedge formed hinged together at the ends having the greater
diameter and having the approach of their opposite ends regulated and secured in
assigned position by a suitably formed regulating screw bolt and socket the bolt
being operated by a fly or like hold or a single wedge piece hinged to the ordinary
base of the instrument may be similarly adjusted.
By means of a small mirror placed at an angle of 45° at one end of the spirit
level attached to the telescope the surveyor can (without removing his eye from
the eye piece) see that the telescope is perfectly level at the moment when he
takes his reading on the staff.
For packing and carriage I prefer to form on the inside of each leg a suitably
shaped shoe or part into which a part of the weight of the rod may lie and when
the legs are drawn together the weight will be encompassed by these parts and by
the aid of catches on the parts the whole may be securely locked together.
Although I have described the invention in connection with a dumpy level it is
also applicable to other mathematical and scientific instruments in which accuracy
of level is essential.
DESCRIPTION OF THE DRAWINGS.
Fig. 1 shews a sectional elevation of a dumpy level and tripod stand with hinged
legs according to the invention.
Fig. 2 is a plan view of the same taken sectionally at about the line AA of
Fig. 1 the upper leaf of the clamp d' being removed.
Fig. 3 is a sectional view of the clamp portions around the ball, the leaves of the
clamp being here shown opened one from the other.
Fig. 4 is a cross sectional view of the legs of the tripod, in the position they
assume when folded each half leg on its fellow, and assembled fitted around the bob:

page_text: or weight of the pendulum adjustment, and held tightly thereto, with the three
shoes interposed, by means of the three latches f³.
Fig. 5 is an external view of portions of the tripod legs at about a point inter-
mediate of the parts a and y Fig. 1, and supposed to be broken out at those points
of the legs the legs however in this fig. being closed together and latched.
Fig. 6 shews the two halves of one leg folded together and hooked. In this fig.
as well as in other of the figures portions of the tripod legs have been shewn as
broken out for convenience of the drawings. a is a dumpy level. b is one leaf of
a hinged connection, being the under half, 6* the hinge thereof. 6 is a screw
with thumb head passing through the screwed socket attached to the leaf b¹ and
engaging in another socket in the leaf b, so as to serve as an adjustment of level of
the instrument. c is a small mirror mounted at an angle of say 45° to the plane of
the level to facilitate reading of its indications.
On the underside of the leaf 6' is a short screw threaded female socket d adapted
to be removably secured on the screwed stem d projecting upwardly from the
ball drigidly attached to the stem d³ at the end of which is the double weight or
bob d¹. This ball d' sockets on three antifriction wheels of which one d' is shown
in side view in Fig. 1, in side view and perspective elevation in Fig. 3. and, by
dotted lines chiefly, in the plan view Fig. 2. The ball d³ takes its position on these
wheels determined by the vertical position of the rod d. This rough adjustment
being arrived at, the upper leaf of the clamp (said clamp being formed by the
said upper leaf and the lower leaf d and wheels d³) is closed down onto the ball
and locked thereonto by means of the latch e, which latch is passed over the
tongue d projecting from the leaf de causing it to be depressed. Normally the
tongue d³ is kept raised from the ball d² by spring d.
The upper part of the ball d³ may be covered with chamois leather or like material
or roughened or otherwise adapted to increase frictional contact to the upper half
of the clamp which half is or may be similarly packed. Side stops d¹º to centralize
the closing of the leaf de may be provided on the top of lower leaf d'. This
part forms the platform of the instrument and to it are hinged the tripod legs f.
At adjusted distances down these legs f to grasp the bob or weight d' when closed
thereon are three shoes f¹ internally packed, as with leather, each forming a socket
of one third of a circle, to be each locked to its neighbouring shoe by a latch ƒ'
and catch are books for hooking the folded half legs together. h are hinges
between the half legs.
When the half legs are open and in correct line, a sleeve h¹ of substantially
cylindrical form is slidden over the joint giving it rigidity, but for folding this
sleeve is slidden back.
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 :-
1. The combination and arrangement of parts of means or apparatus for supporting
and rapidly adjusting the level of surveyor's levels or other scientific instruments
whereby a preliminary adjustment by means of a pendulum support and single
screw final adjustment can be attained substantially as set forth.
2. The combination or arrangement and construction of the parts forming the
final adjustment of the instrument for use substantially as and for the purpose
herein set forth and shewn by the drawings.
3. The construction and arrangement of parts of folding legs of surveyor's levels
or other scientific instruments, substantially as set forth.
Dated the 27th day of March 1894
WM. BROOKES & SON,
55 & 56, Chancery Lane, London, Agents for the Applicant.