Improvements in Surveying Instruments to be Used in Mines or Elsewhere.
Year: 1898

page_text: Date of Application, 7th Dec., 1898
Complete Specification Left, 7th Sept., 1899 -Accepted, 7th Oct., 1899
PROVISIONAL SPECIFICATION.
Improvements in Surveying Instruments to be Used in Mines or
Elsewhere.
We, THOMAS ALOYSUIS O'DONAHUE, Surveyor, of 35, Princess Street, Wigan,
and JOSEPH HALDEN, of the Firm of J. Halden & Co., Opticians and Surveying
Instrument Makers, of S, Albert Square, Manchester, both in the County of
Lancaster, do hereby declare the nature of this invention to be as follows:-
This invention relates to surveying instruments such as miners' dials and
the like, the object of the invention being to dispense with an external arc or
other external device for reading vertical angles.
For this purpose one of the pivots or trunnions of the rocking ring or limb
which carries the sights or telescope is fixed upon the said rocking ring or limb
and is made to project inside the compass of the instrument where a small fine
toothed bevel wheel or sector is fixed thereon gearing with an exactly similarly
toothed wheel or sector, capable of revolving or rocking on a vertical axis on
which is fixed a finger or index moving along a suitable graduated arc or dial
on the face of the compass in a curve concentric with the said axis.
Thus the angle of any inclination of the rocking ring or limb is indicated
exactly by the movement of the finger aforesaid along the arc or dial and the
reading of vertical angles can be accomplished without any external parts on
the instrument, and on the same face or plate on which the horizontal angles
are indicated.
We do not limit ourselves to the exact construction hereinbefore described
as the same may be varied so long as the principal feature of our invention is
adhered to which is the passing of the pivot through to the inside of the casing
of the compass so that all the mechanism for reading the vertical angles is
contained therein as well as the levels and compass.
By this arrangement the vertical angles can be more easily read, and the
mechanism above described is less liable to derangement than is an external
arc, and forms no obstruction to the manipulation of the instrument.
Dated this 6th day of December 1898.
Improvements in Surveying Instruments to be Used in Mines or
Elsewhere.
We, THOMAS ALOYSUIS O'DONAHUE, Surveyor, of 35, Princess Street, Wigan,
nd JOSEPHI HALDEN, of the Firm of J. Halden & Co., Opticians and Surveying
071

page_text: Instrument Makers, of 8, Albert Square, Manchester, both in the County of
Lancaster, 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 surveying instruments such as miners' dials and
the like, the object of the invention being to dispense with an external arc or
other external device for reading vertical angles.
In the accompanying drawing, Fig. 1 is a sectional elevation of a dial such
as hereinbefore named, Fig. 2 is a plan of the same, and Fig. 3 is a side view
of a small portion of the rocking ring. In these illustrations similar letters
refer to similar parts.
For the purpose of this invention one of the pivots or trunions a that is fitted
in the rocking ring b which carries the sights or telescope is formed to project
inside said ring; a fine toothed bevel wheel or sector c is fitted on the projecting
portion a of said trunnion and gears into a precisely similarly toothed wheel
or sector c that is fitted to the outer end of a finger or index which is capable
of moving or turning on a vertical axis as d, the inner or index end of the
finger being thereby caused to move along a suitably graduated arc or dial as e
on the face of the compass in a curve concentric with the said axis. The angle
of any inclination of the rocking ring or limb is indicated exactly by the
movement of the index end of the finger d along the arc or dial e and the
reading of vertical angles can thereby be accomplished without any external
parts on the instrument and on the same face or plate on which the horizontal
angles are indicated.
We do not confine ourselves to the precise construction hereinbefore described
as a variation may be made without departing from the main feature of our
invention, which is the extension of the pivot on the inside of the casing of
the compass in combination with mechanism for reading the vertical angles
therein, as well as the levels and compass.
By this arrangement the vertical angles can be more easily read and the
mechanism is less liable to derangement and does not obstruct the manipulation
of the instrument.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is :-
1. In miners' dials and like surveying instruments the combination with the
pivot or pivots on a rocking ring that carries the sights or telescope, of a finger
or index moving or turning on a vertical axis and actuated by a bevel wheel or
sector fitted on an extension of one of said pivots which is formed to project
inside the rocking ring, the inner or index end of said finger being thereby
caused to move along a graduated are on the face of the compass in the manner
and for the purpose substantially as hereinbefore described.
2. A miners' dial or like surveying instrument in which the angle or inclina-
tion of the rocking ring and the reading of the vertical angles is accomplished
on the same face or plate on which the horizontal angles are indicated without
any external parts on the instrument in the manner substantially as herein-
before described.