US979531A - Instrument for surveying and like purposes. - Google Patents

Description

E. H. V. MBLVILL. INSTRUMENT FOR SURVEYING AND LIKE PURPOSES.

APPLIOATION FILED JUNE 1, 1910.

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III'IIII E. H. V. MELVILL. INSTRUMENT FOR SURVEYING AND LIKE PURPOSES.

APPLIOATION FILED JUNE 1. 1910.

Patented Dec. 27, 1910.

2 EHSETB-BEEBT 2-.

Em a EDW'ARID HARKER "JINTCENT MELVILL, F JOHANNESB'UBG, TEAN'SVAAL.

INSTRUMENT FOE SURVEYING AND LIKE PURPOSES.

Specification of Letters Patent.

Patented Dec. 2?, 1919.

Application filed June 1, 1910. Serial No. 564,507.

To all whom it may concern:

cnx'r Mnnvrnn, engineer and surveyor, a subject of the King of Great Britain, residing at New Stock Exchange Building, Johannesburg, Transvaal, have invented new and useful Improvements in Instruments for Surveying and Like Purposes, of which the followin is a specification.

he purpose of the present invention is to provide a simple, compact and light instrument which is of very general utility for making observations in surveying and allied work.

The complete instrument comprises essentially the following parts: a graduated limb; a support therefor; a universal oint arrangement in the support by means of which the limb may be positioned horizontally, in any vertical plane, or in intermediate planes; an alidade mounted for rotation on the limb; and sighting moans upon the alidade.

In the accompanying drawings: Figure I is an elevation of the complete instrument illustrating its two principal positions: Fig. ii is a view of the upper part of the instrument detached and viewed from above: Fig. Ill is similar view of a modified form.

Referring to Figs. 1 and H, the limb 1 is formed below with a threaded socket 2 for detachably securing it to its support in the usual manner. Upon its upper side the limb is furnished with an axis upon which the alidade 3 rotates. A window 4t is formed in the alidade for observing the usual graduated circle 5 upon the limb and the vernier 6 upon the alidade. For reading the vernier, a microscope 7 of any appropriate type may be hinged to a ring 8 encircling the axis. 9 is the clamp for fixing the alidade to the limb and 10 the tangent screw for accurately adjusting the limb after such fixing. The sighting means, in this form of the invention consists of the folding sight vanes 11 and 12 arranged diametrically upon the alidade. lhe ocular vane 11 is formed with a vertical slit 13 and a pin hole 14; while the foresight vane 12 is complementally fitted with a vertical wire 15 and a cross wire 16. Suitable leveling devices are fitted for setting the alidade and limb both horizontally and vertically. These, as shown, consist of bubble tubes 17 and 18 disposed on the alidade parallel therewith and perpendicular to one another. Said tubes 17 and 1S serve for setting the alidade and limb 1 w horizontal and sight from the face of the e it known that I, EDWARD Hannnn 1) 'rl former. If preferred a single circular or box level may be used in their stead. F or the vertical set-ting, tube 19 is fixed perpendicularly to the alidade and passes through the same to afford the greatest effective length without projecting to an inconvenient extent. It sights from the edge of the alidade. A further bubble tube 20 disposed similarly to tube 17 but sighting from the edge of the alidade, is provided for such purposes as setting the zero of the limb when taking vertical angles, or when using the instrument as a clinometer as described below. In some cases, a single internally barrel shaped tube sighting both from the face and the edge of the alidade may be substi tutcd for tubes 17 and 20. 21 is a magnetic compass which in this instance is of the trough type. It is furnished with the usual graduations 22. To adapt the instrument for use as a clinometer for setting on inclined surfaces, a fiduciary surface 23 is attached to the limb so that when the vernier reads zero on the graduated circle 5, such fiduciary surface is pa'allel with the line of sight. The support shown in Fig. 1 includes a base plate 24: suitably formed below for attachment. to a tripod or other appropriate stand. 26 is a leveling plate adjustable angularly with respect to the base plate 24L by well known leveling screws 27 and counter plungers 28. Said plates 26 carries a vertical axis 29 upon which a socket 30 revolves: 31 being a clamp for locking said parts together. 32 is a bubble tube mounted upon the socket for setting axis 29 truly vertical. Socket 30 carries at its upper end the socket 33 of a ball and socket joint; the ball of which is denoted by Atone side, socket 33 is formed with a slot to permit the ball and parts above it to V be turned through an angle of not less than 90, that is from the vertical to the horizontal position. The socket 30 and axis 529 together with the ball 3% and socket 33 constitute the universal joint device which is the essential feature of the support. The ball and socket pair is conveniently employed because in addition to the large angular movement permitted by slot 35, it affords the limited universal adjustment of the supported instrument, for which it is commonly employed in surveying apparatus; but as occasion requires the ball and socket may be substituted by a simple pivot,

To facilitate orientation of the zero of the graduated circle 5 the ball 34: may support an axis 36 carrying a socket 3'? to which the limb 1 is detachably screwed. 38 is a clamp for fixing said socket to said axis and 39 a tangent screw for accurately adjusting the relative position of said parts. It is to be understood that provided the universal movement as described is afforded, the construction of thesupport may be varied to any desired extent.

Fig. III shows a form of the upper part of the instrument which is designed for rather more accurate observations than that described. To this end the sighting means consists of a telescope 40 which, in order to minimize the height of the instrument and enhance its compactness, is positioned approximately at the level of the alidade 3 and eccentrically therewith. The telescope is pivoted to revolve perpendicularly to the alidade for the purpose, for example, of projecting into the plane of measurement an object lying outside of said plane. The flange 41, of the telescope and the adjacent fixed flange 42 are marked with graduations 43 which enable the telescope to be placed parallel with the alidade or at any desired angle therewith. a4 is a clamping screw for the telescope axis. The alidade is furnished with two windows at and verniers 6 in order that readings may be taken with the telescope successively to one side and the other of the line of sight, to compensate for its eccentricity. In this form of instrument the magnetic compass 21 is preferably of the telescopic variety, as illustrated.

The following examples will illustrate briefly some uses to which the instrument may be put: it being assumed that the instrument is assembled and mounted upon its tripod, as seen in Fig. I. In measuring horizontal angles, the axis of the alidade 3 is set vertically by bubble tubes 1'? and 1.8 (as shown by the full lines of Fig. I) the line of sight directed successively to the datum point and the object, and the differences of the readings at the graduated circle 5 taken. Thus, to find the magnetic bear ing of an object, the alidade is clamped to the limb with the vernier 6 reading zero on the graduated circle The limb and ali dade together are next rotated on axis 36 until the zero of the compass scale 22 registers zero with the point of the compass needle, whereupon the limb is clamped firmly to the support. The alidade is then freed and the line of sight directed to the object, when the reading on the graduated circle gives the desired bearing. To measure vertical angles, the instrument is rotated about the ball joint to bring the axis of the alidade horizontal which is indicated by level 19. ,This disposition of the instrument is indicated by the dotted lines in Fig.

I. After turning the instrument about axis 29 into the required vertical plane, the angle in question is measured in the usual way by directing the line of sight first to the datum point and then to the object and taking the difference of the readings on the graduated circle. Measurement of vertical angles from a horizontal datum plane is effected by setting the zero of the graduated circle as in the case of the magnetic bearing described hereinbefore, but employing the level 20 as the indicator instead of the compass needle. It is advantageous when taking vertical angles first to put axis 29 vertical by means of level 32, so that the alidade, having once been placed vertically, will maintain its vertical position when rotated about said axis to take observations in different vertical planes. In the same way bearings and angles in any inclined plane may be taken directly upon first setting the alidade in the required plane, which may be done by judgment or by sighting to known points in the plane. In this case the zero is oriented, when required, by observation of some known point.

From the foregoing description it will be evident that owing to its universally jointed support, the one graduated circle 5 may be employed to measure angles in any plane, whether vertical, inclined or horizontal.

When employing the instrument as a clinometer for measuring the inclination of a sloping surface, the upper part is removed from the support and the fiduciary surface 23 is placed upon the surface in question. The alidade being then set to bring bubble tube 20 horizontal. the reading of the graduated circle will give the required measurenent.

The instrument has here been described as embodying all the important elements desirable to adapt it for a very wide range of uses, but according to the special purpose for which it is projected, it may be modified in details without varying it essentially. Thus, in some cases, the magnetic compass may be omitted: or in an instrumentintended for stope measurements in the plane of the stope, the bubble tubes or at least those marked 17, 18 and 19 may be suppressed. Again, as already mentioned, the support may be very considerably modified provided it embodies means for universally positioning the limb and alidade.

What I claim and desire to secure by Letters Patent is 1. In a surveying instrument, the combination of a limb, a support therefor including universal limb may be adjusted in a multiplicity of planar positions including both horizontal and vertical planes, an alidade mounted for rotation upon the limb, and sighting means upon the alidade.

jointing means whereby the l 2. In a surveying instrument, the combination of a limb, a support therefor including universal jointing means whereby the limb may be adjusted in a multiplicity of planar positions including both horizontal and vertical planes, an alidade mounted for rotation upon the limb, sighting means upon the alidade, and level means for setting the limb and alidade in both vertical and horizontal planes.

3. In a surveying instrument, the combination of a limb, a support therefor including universal jointing means whereby the limb may be adjusted in a multiplicity of planar positions including both horizontal and vertical planes, an alidade mounted for rotation upon the limb, sighting means upon the alidade and means for indicating datum positions of the limb.

i. In a surveying instrument, the combination of a limb, a support therefor including universal jointing means whereby the limb may be adjusted in a multiplicity of planar positions including both horizontal and vertical planes, an alidade mounted for rotation upon the limb, sighting means upon the alidade, and a magnetic compass for orienting the zero of the limb.

5. In a surveying instrument, the combination of a limb, a support therefor including universal jointing means whereby the limb may be adjusted in a multiplicity of planar positions including both horizontal. and vertical planes, an alidade mounted for rotation upon the limb, sighting means upon the alidade, and a bubble tube for setting the limb to a datum position in vertical planes.

6. In a surveying instrument, the combination of a limb, a support therefor, an alidade, sighting means on the alidade, said support including a vertical axis, a ball joint positioned above said axis and being capable of universal movement within a limited range and being also capable of movement through at least 90 in one plane.

7. In a surveying instrument, the combination of a limb, a support therefor, an alidade and sighting means thereon, said support including a vertical axis, leveling means for setting said axis truly vertical,

and a joint above the axis affording angular movement of the upper part of the support with respect to said vertical axis of at least 90.

8. A support for a surveying instrument having means at the top for securing the instrument thereto and being constructed for movement to level the instrument and including universal jointing means affording the upper part of the support movement into any plane in relation to the base thereof said support including an axis below the universal jointing means.

9. A support for a surveying instrument having means at the top for securing the instrument thereto and being constructed for movement to level the instrument and including universal jointing means afiording the upper part of the support movement into any plane in relation to the base thereof, said support also including an axis above the universal jointing means, whereby the instrument may be rotated with respect thereto and an axis below the universal jointing means.

10. In a surveying instrument, the combination of a limb formed for attachment to a support, an alidade mounted for rotation thereon, sighting means carried by the alidade, a bubble tube upon the alidade parallel therewith and an extension of the limb providing a plane face the length of which is parallel with the plane of the limb, said face forming a fiduciary surface for setting upon another surface of which the inclination is required to be measured.

11. In a surveying instrument, the combination of a limb, an alidade mounted for rotation thereon, and a sighting telescope eccentrically mounted upon the alidade, and being pivoted to rotate perpendicularly thereto about an axis. approximately in the plane of the alidade.

In testimony whereof I affix my signature in presence of two witnesses.

EDWARD HARKER VINTCENT MELVILL.

"Witnesses \VnsLnY E. JOHN, J. VVARREN VENNING.

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