Surveying Instrument
Year: 1887

page_text: Date of Application, 3rd May, 1887.
Specification Accepted, 14th June, 1887.
Figure, 1, is a perspective view of the parts of my apparatus separated from each.
other.
and
Figure, 2, is a like view of the same combined for use.
Figure, 3, is a side elevation of my apparatus having attached thereto a plane board
Figure, 4, is a vertical central section of the same.
Letters of like name and kind refer to like parts in each of the figures.
My invention is designed mainly for use in connection with Plane Table Surveying
Instruments, but is equally applicable for other forms of surveying and engineering
instruments, photographic cameras, etc. and has for its object the ready and accurate
horizontal adjustment of such instruments and the rotation of the same without
change of such adjustment, to which end said invention.
Consists, principally, in a tripod head for surveying instruments in which is
combined a leveling mechanism, and a mechanism for circumferential adjustment that
act independently and the axes of whose motions intersect at a point within or above
the instrument supporting table, substantially as and for the purpose hereinafter
specified.
It consists, farther, in a tripod head for surveying instruments in which the axial
bearing for the supporting table is in part formed by a spindle that is journaled
within a bearing which is fitted to and adapted to be moved upon or over the face of
a relatively fixed concave plate and is in part formed by the direct bearing of a
convex boss upon the face of said concave plate, substantially as and for the purpose
hereinafter shown.
It consists, farther, in a tripod head for surveying instruments, in which the sup-
porting table is independently journalled within a convex plate and a concave plate
that are combined and adapted to bear upon and move over the opposite sides of a

page_text: stationary concavo-convex plate, and by a relatively inward pressure to be engaged
with and locked upon the same substantially as and for the purpose hereinafter set
forth.
It consists, farther in a tripod head for surveying instruments in which the
supporting table is independently journalled within a movable convex plate that rests
upon the concave face of a stationary concavo-convex annular plate, is provided with
a hollow axial spindle which extends through a central opening in the same and is
combined with a movable concave plate that fits over said spindle and bears upon the
convex face of said stationary plate, and a nut which fits upon a threaded portion of
said spindle, and is adapted to press said movable plates by a relatively inward move-
ment, firmly against and lock the same upon the faces of said stationary plate,
substantially as and for the purpose hereinafter shown and described.
It consists farther, as an improvement in tripod-heads for surveying instruments,
in the combination in one organization of the following elements: viz. A stationary
annular concavo convex plate that is adapted to be connected with and supported by
pivoted legs, a movable convex plate provided with a hollow axial spindle, a movable
concave plate which is fitted over and upon said spindle, means substantially as shown
whereby said movable plates may be pressed toward each other and caused to bear
upon the opposite faces of said stationary plate, and an axial spindle that is adapted
to pass into and rotate independently within said hollow spindle, and at its upper end
is adapted to be attached to an instrument supporting table, substantially as and for
the purpose hereinafter specified.
It consists, farther as an improvement in tripod heads for surveying instruments, in
the combination of the following elements: viz. a stationary annular concavo-convex
plate, a movable convex plate, and a movable concave plate, that are adapted to bear
upon the opposite faces of said stationary plate and are combined by means of a
hollow axial spindle having a peripheral thread and an encircling nut, and a spindle
which is journalled within said hollow spindle and has its upper end adapted to receive
an instrument supporting table, and at said end is provided with an annular convex
boss that conforms to and rests upon the upper concave face of said plate substantially
as and for the purpose hereinafter shown.
It consists farther, as an improvement in tripod heads for surveying instruments, in
the combination of the following elements: viz. a stationary annular concavo-convex
plate, a movable convex plate and a movable concave plate, that are adapted to bear
upon the relatively opposite faces of said stationary plate, and are combined by means
of a hollow axial spindlo provided with a peripheral thread and encircling nut, a
spindle which has its upper end adapted to receive an instrument supporting table
journalled within said hollow spindle, and means substantially as shown whereby said
journalled spindle may be locked in place and preventing from rotating, when desired,
substantially as and for the purpose hereinafter set forth.
It consists finally, as an improvement in tripod heads for surveying instruments, in
the combination of the stationary annular concavo convex. plate, the movable convex
plate provided with the hollow peripherally threaded spindle and encircling nut, the
movable concave plate adapted to fit over said spindle and the table supporting and
journaling spindle which has a threaded lower end and an encircling nut and at its
upper end is provided with an annular boss that has a convex lower side and at its
upper side is adapted to be connected with an instrument supporting table, substantially
as and for the purpose hereinafter shown and described.
In the carrying of my invention into practice, I employ an annular concavo-convex
plate, A, that at suitable points around its periphery is provided with lugs, a, which
are each adapted to have pivoted thereon the upper ends of a bifurcated supporting
leg, B. Within the upper concave side of the plate, A, is placed a plate, U, which
preferably has a hemispherical form with its convex side uppermost and its edge, c,
which is considerably broadened-resting upon and conforming to the curvature of
the upper face of said plate. From the centre of said plate, C, a hollow spindle, c¹,
extends downward through the central opening, a¹, of said plate, A, and upon its lower
portion is provided with a peripheral thread, c³, and wing nut, D.

page_text: Fitted closely over the spindle, c', and against the lower face of the plate, A, is a
second plate, E, which preferably has a hemispherical form and has its edge, e, con-
formed to the curvature of said plate, A, said part being substantially the same as the
plate, C. The nut, D, operates to move said plate, C, and, E, together so as to cause
their engaging faces, c, and, e, to bear upon the faces of said plate, A, with any
desired force. When said nut is sufficiently loosened, said plates, C, and, E, may
he moved laterally in either direction, within the limits of motion permitted the
spindle, c, by the opening, a', and as the faces of said plate, A, are concentric, it
will be seen that such movements will be smooth and with the same friction of parts
at one point as at any other point within the field of motion. Journalled within the
hollow spindle, c¹, is a spindle, F, that closely fills the same, and upon its lower, pro-
jecting end, f, is threaded and provided with a wing nut, G. The upper end of said
spindle is provided with a circular head, f', which upon its lower side forms an
annular boss, that conforms to the curvature of the upper face of the plate A, and
bears
upon the
same, outside of the plate, C, such bearing furnishing the entire
support for said spindle and leaving said plate, C, free from any downward pressure
except such as is produced by its own weight, the weight of the lower plate E, and
the operation of the nut, D.
The upper side of the head, f, is provided with a central peripherally threaded
hub, f, upon which is fitted a plate, H, that has a corresponding interiorily threaded
opening, h. Said plate extends outward to or slightly beyond said head and has a
firm bearing upon the upper surface of the same. For the purpose of lessening the
weight of said head it is provided with an annular groove, f, which extends from a
point near its hub nearly to its outer edge, as shown and leaves a bearing for said
plate, H, only at the inner and outer portions of said head. Said plate, H, receives
and has secured to its upper side a plane table, I, or equivalent part, for the support
of the instruments which are to be employed.
In the use of my apparatus, the legs of the tripod are firmly seated upon the
ground, the confining nuts loosened and the table adjusted to a perfectly horizontal
position by such movement, as may be necessary, of the engaging parts over or upon
the concavo convex plate, after which, by tightening the upper nut, the plates, C,
and, E, will be caused to firmly grasp said plate and operate to preserve the adjust-
ment thus effected. While the table is thus held in a horizontal position, it is free to
be turned upon its axis and may be readily locked in or released from any desired
circumferential position, by tightening or loosening the lower nut, without in any
manner affecting the horizontal adjustment.
Having now particularly described and ascertained the nature of the said invention
and in what manner the same is to be performed I declare that what I claim is.
1. A tripod head for surveying instruments in which is combined a leveling
mechanism, and a mechanism for circumferential adjustment that act independently
and the axes of whose motions intersect at a point within or above the instrument
supporting table, substantially as and for the purpose specified.
2. A tripod head for surveying instruments in which the axial bearing for the
supporting table is in part formed by a spindle that is journalled within a bearing
which is fitted to and adapted to be moved upon or over the face of a relatively fixed
concave plate, and is in part formed by the direct bearing of a convex boss upon the
face of said concave plate, substantially as and for the purpose shown..
3. A tripod head for surveying instruments in which the supporting table is
independently journalled within a convex plate and a concave plate that are combined
and adapted to bear upon and move over the opposite sides of a stationary concavo
convex plate, and by a relatively inward pressure to be engaged with and locked upon
the same, substantially as and for the purposes set forth.
4. A tripod head for surveying instruments, in which the supporting table is
independently journalled within a movable convex plate that rests upon the concave
face of a stationary concavo convex annular plate, is provided with a hollow axial
spindle which extends through a centre opening in the same and is combined with

page_text: '
a movable concave plate that fits over said spindle, and bears upon the convex
face of said stationary plate, and a nut which fits upon a threaded portion of said
spindle and is adapted to press said movable plates by a relatively inward movement,
firmly against and lock the same upon the faces of said stationary plate, substantially
as and for the purpose shown and described.
5. As an improvement in tripod heads for surveying instruments the combination.
in one organization of the following elements: viz. a stationary annular concavo-
convex plate that is adapted to be connected with and supported by pivoted legs, a
movable convex plate provided with a hollow axial spindle a movable concave plate
which is fitted over and upon said spindle, means, substantially as shown whereby said
movable plates may be pressed toward each other and caused to bear upon the opposite
faces of said stationary plate, and an axial spindle that is adapted to pass into and
rotate independently within said hollow spindle, and at its upper end is adapted to be
attached to an instrument supporting table, substantially as and for the purpose
specified.
6. As an improvement in tripod heads for surveying instruments, the combination
of the following elements: viz. a stationary annular concavo-convex plate, a movable
convex plate and a movable concave plate, that are adapted to hear upon the opposite
faces of said stationary plate, and are combined by means of a hollow axial spindle
having a peripheral thread and an encircling nut and a spindle which is journalled
within said hollow spindle, and has its upper end adapted to receive an instrument
supporting table, and at said end is provided with an annular convex boss that
conforms to and rests upon the upper concave face of said plate, substantially as and
for the purpose shown.."
7. As an improvement in tripod heads for surveying instruments the combination
of the following elements: viz. a stationary annular concavo convex plate, a movable
convex plate and a movable concave plate, that are adapted to bear upon the relatively
opposite faces of said stationary plate, and are combined by means of a hollow axial
spindle provided with a peripheral thread and encircling nut a spindle which has its
upper end adapted to receive an instrument supporting table, is journalled within said
hollow spindle, and means substantially as shown, whereby said journalled spindle may
be locked in place and prevented from rotating, when desired substantially as and for
the purpose set forth.
8. As an improvement in tripod heads for surveying instruments, the combination
of the stationary, annular concavo-convex plate, the movable convex plate provided
with the hollow peripherally threaded spindle and encircling nut, the movable concave
plate adapted to fit over said spindle and the table supporting and journaling spindle
which has a threaded lower end and an encircling nut, and at its upper end is provided
with an annular boss that has a convex lower side and at its upper side is adapted to
be connected with an instrument supporting table, substantially as and for the purpose
shown and described.
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