WO2020049582A1

WO2020049582A1 - Ternate cross staff

Info

Publication number: WO2020049582A1
Application number: PCT/IN2019/000031
Authority: WO
Inventors: N Nagarathinam; M Balaji; Basil Johnson; S Thatchinamoorthi; R Muthumaran
Original assignee: N Nagarathinam; M Balaji; Basil Johnson; S Thatchinamoorthi; R Muthumaran
Priority date: 2018-09-07
Filing date: 2019-09-04
Publication date: 2020-03-12

Abstract

Research project deals, intent of the setting out of right angles and accurate centring over the survey station will be done over this method of apparatus and carrying the combustion of prism with reduction of cost. The cross staff is worked the triangulation principle. The ternate cross staff is used for viewing the object by stacking of prism below and above the plain object vane. The objects are clearly viewed and coincide with the line obtained the straight cross hair despite that, laser will be provided for day-to-night time periods and illuminated coat will be provided over the staff. The target objects are aligned to coincide with the cross hair when the objects are setting out. The cross staffs ate properly setting over the survey station by adjusting screws and accurately levelled by sprit level. The ternate cross staff is used to setting out the offsets for various survey station like highways and sewer lines.

Description

TERNATE CROSS STAFF

1.1.1 DEFINITION:

Surveying is the art of making horizontal measurements to ascertain the relative positions of different objects on the surface of the earth. Leveling is the art of determining the vertical distances or elevations of different objects on the surface of the earth. Although surveying and leveling are quite often considered as different operations, in a collective sense surveying includes leveling. Thus the observations made in surveying and leveling are plotted on a map or plan to obtain the shape and extent of any portion of earth’s surface.

1.1.2 OBJECTIVE OF SURVEY:

The preliminary object of surveying and leveling is the preparation of a plan or map. A plan or map is the plotting made using the observations and computations made in a survey. A plan or map is drawn adopting some scale. The drawing made is called a map if the scale is small, e.g., a map of India, and is called a plan if the scale is large, e.g., a plan of a building. In general, in a plan or map only horizontal distances are shown. However, sometimes vertical distances are also represented approximately by means of contour lines, hachure or other systems.

1.2 CLASSIFICATION OF SURVEYING:

i. Geodetic Surveying

• Geodetic surveying is also called trigonometrically surveying which deals with long distances and larger areas. Thus in geodetic surveying the curvature of the earth is taken into consideration. It is widely used to determine the precise positions on the surface of the earth. These distinct points are called control stations which are used in engineering surveys, topographical surveys, cadastral surveys, etc. This survey conducted in India by Survey of India. ii. Plane Surveying

• Plane surveying is adopted for small distances and small areas. In this survey the effect of curvature of the earth is ignored and the line connecting two points is treated as a straight line and the figure formed by joining these points is a plane triangle. This survey needs only the knowledge of geometry and plane trigonometry. Generally, surveys up to an area of 260 sq. km are covered by plane surveying. The degree of accuracy expected in plane surveying is comparatively low. This survey is conducted by the Public Works Department, Railways Department, etc.

1.3 PRINCIPLES OF SURVEYING:

General principles of surveying comprise of the following:

• To work from the whole to part

• To locate a new station by at least two points.

1.4 CHAIN SURVEYING:

• To obtain necessary data for the description of the boundaries of a land.

• To find the area of a land.

• To collect necessary data for preparing a plan

• To re- establish the boundaries of an area already surveyed.

• To divide the given land into a number of units of required sizes.

1.5.1. CHAIN:

• Chains are used to measure horizontal distances. Chains are formed of straight links of galvanized mild steel wire called links.

• The chain is made of mind steel. The ends of the chin are provided with brass handles for dragging the chain on the ground the outside of the handle is the zero point or the end point of the chain and the length of the chain measured from the outside of one handle to the outside of the other. The length of a link is the distance between the centers of the two consecutive middle rings.

_• The end links include the handles. Metallic tags are indicators of the chain to facilitate quick reading of fraction of chain in surveying measurements. Metric survey chains are available in lengths of 20m and 30m. The 20m chain contains 100 links whereas 30m. Chain contains 150 links. One link of both the type of chain measure 20cm. 5.2 ARROWS:

• AJTOWS or making pins are made of tempered steel wire 4mm in diameter and generally 10 arrows are supplied with a chain. An arrow is inserted into the ground after the chain length is measured on the ground. Usually the length of an arrow is 40crri and one end of it is made sharp and the other end is bent into a circle for facility of carrying. 5.3. PEGS:

• Wooden pegs are used to mark the positions of the stations terminal points of a survey line. They are made of hard timber, generally 2.5cm or 3 cm square and 15cm long, tapered at the end. 5.4. RANGING RODS:

• The ranging rods are used for making the positions of stations and for ranging the lines. They are made of ell seasoned straight grained timber teak. They circular in cross section of 3cm diameter and have a length of either 2 or 3cm, length being more common. They are shod at the bottom with a heavy iron points. In order to make them visible at a distance, they are pained alternatively black and white or red and white. 1.5.5. OFFSET ROD:

• Offset rod is similar to that of ranging rod. They are should with pointed iron shoe at one end, ad provided with a notch or a hook at the other for pulling or pushing the chain through a hedges or other obstructions.

1.5.6. PLUMBING ROD:

• While chaining along sloping ground, a plump is required to transfer the points to the ground. It is also used for accurate centering of the theodolite compass, plane table etc. over a station mark and for testing the vertically of ranging poles.

2. INSTRUMENTS USED FOR SETTING OUT RIGHTANGLES

2.1 CROSS STAFF:

The cross staff is used for,

• Finding out foot of the perpendicular from a given point to a line.

• Setting right angle at a given point on a line.

The cross staff are generally following types,

1. Open cross staff

2. The French and

3. The Adjustable

4. Optional Square

5. Prism square, the first one is commonly use.

2.1.1 OPEN CROSS STAFF:

• It consists of two parts: - 1) the head; 2) the leg. The common type of cross staff consists of 4 metal arms with vertical slits for sighting through. The head is fixed to the top of an iron stand about 1.2 to 1.5 m long this is driven in to the ground. For setting perpendiculars lines, one pair of opposite arms is aligned with the chain line._. It is specially used for setting off and marking contour lines.

In setting out a right angle at point on the chain line:

• The cross staff is held vertically over the given point on the chain and turn until the ranging road at either end of the chain line is bisected the line of slight through 1 pair of the opposite slits. Then the line through the other pair of slits which is at right angles to the chain line through the other pair of slits which is at right angles to the chain line. Line may be marked by a ranging rod at inconvenient point on the sighted.

2.1.2. FRENCH CROSS STAFF:

• The octagonal form cross staff is the French cross staff. It consists of an octagonal brass tube with slits on all eight sides. If has an alternate vertical slit and an opposite vertical window with a vertical horse hair or affine wire on each of the four sides. These are used for setting our right angles. On the other side are vertical slits, which are at 45 degrees to those previously mentioned, for setting out angles of 45 degrees.

• The base carries a socket so that it may be fitted on the pointed staff when the instrument is to be used. The sight being too close (only 8 cm apart) it is inferior to the open type

2.1.3. ADJUSTABLE CROSS STAFF:

• It consists of a brass cylindrical tube about 8 cm in diameter and 1 cm in deep, and is divided in the centre. The upper cylinder can be rotated relatively to the lower one by a circular rack and pinion arrangement actuated by screw. Both are provided with sighting slits. The lower part is graduated to degrees and sub divisions, while the upper one carries a Venire. Thus it may be used for setting out angles of any magnitude. It has a magnetic compass at the top, which may serve to take the bearing of the line. 1.4. OPTICAL SQUARE:

• An optional square is a compact hand instrument used in setting out right angles with greater accuracy than a cross staff. It consists of a circular box about 5 cm in diameter and 1.25 cm deep in which two mirrors are fitted at right angles to the plane of instruments. The mirror‘h⁵ called the horizontal glass which is half silvered and half uncovered. The mirror is known as index glass is known as wholly silvered. There are three openings on the side of box at e, b and c. the opening e is pin hole for eye, b is small rectangular slot placed opposite to pin hole and c is large rectangular slot placed at right angle to line joining e & b

• The surveyor simply turns the optical square upside down which throws the aperture for the object on that side. 1.5 PRISM SQUARE:

• It is a modem instrument and is a very use full for setting out right angles. It is based on the same principles as the optical square and is used in same manner. It requires no adjustment, since the angle between reflecting surface of the prism (45 degree) is fixed. It is unaffected by dust & can be used in poor light. For taking offset to an object the observer holds the instrument in his hand & slights directly over the prism at ringing of station.

DESCRIPTION OF THE PROJECT

Setting out of right angles and accurate centering over the survey stations will be done over this method of apparatus and carrying the combination of prism with reduction cost. The cross staff is worked under the triangulation principle. The Temate cross staff is used for viewing the objects by stacking of prism above and below the plain object vane. The objects are clearly viewed and coincide with the line obtaining the straight cross hairs. The target objects are aligned to coincide with the cross hairs when the objects are setting out. The cross staffs are properly setting over the survey station by adjusting screws and accurately levelled by sprit level by that, used to view the objects in the 3D view of the sights.

FIG 1 REPRESENTS THE FULLY INSTALLED FINAL SETUP

FIG 2 REAR VIEW

FIG 3 CROSS SECTIONAL VIEW

3.1 OBJECTIVE:

• To find the foot of the perpendicular from a given point to a chain line.

• To set out a perpendicular at a given point on a chain line.

• To eliminate the errors from misalignment.

• To provide accurate leveling on any surface of earth.

3.2 PRINCIPLE OF THE PROJECT:

A TERNATE CROSS STAFF works on the Laws of Reflection which states that the light from the object falls on one mirror at a 45° angle from the object and is reflected. This reflected light then falls on another mirror and is again reflected until it reaches the human eye. 3.3 DRAWING DESCRIPTION:

FIG 3.3.1 TOP VIEW OF CASING

Fig 3.3.1 shows the internal parts of the casing in which 1. Eye piece are used to focus the object by Simple Glass. 2. The internal pipe is connected between the Eye piece and Object vane.3. All internal elements are covered by cover pipe. 4. A battery is used to gives the power to the Lighting arrangement. S.The clear view of cross hairs in between the prism by lightings.6. The triangular shaped optical prism is fixed outer edge of casing. 7. The object vane is located below the top Prism in which gives straight line object view from Eye piece.

FIG 3.3.2 CROSS SECTION OF CASING

Fig 3.3.2 shows the section view along the longitudinal section from Fig 3.3.1 . it shows 1. The casing is covered top cap. 2. All internal elements are covered by cover pipe. 3. The internal pipe is connected between the Eye piece and Object vane 4. Eye piece are used to focus the object by Simple Glass. 5. The bottom cap is closed to the cover pipe. 6. Median Pipe is connected between Closer pipes to bottom cap. 7. Closer Pipe are connected to the Ranging pole. 8. The clear view of cross hairs in between the prism by lightings. 9. The top Triangular prism is located over the central eye piece. 10. The object vane is located below the top Prism in which gives straight line object view from Eye piece.l l. The bottom Triangular prism is located below the central eye piece.

FIG 3.3.3 REAR VIEW OF CASING

Fig 3.3.3 shows the rear side view of the casing. It consists 1. Adjacent side glass of the top prism.2. The adjacent glass is partially shadow on left side by tap 3. The right half shadow of the bottom prism by tap. 4. The object vane of the straight view glass are located between the two prisms. 5. Adjacent side glass of the top prism. FIG 3.3.4 FRONT VIEW OF CASING

Fig 3.3.4 shows the Front view of the casing in which 1. The central cross hair is used to clear view of object in straight line. 2. The cross hairs are located along lateral direction of the eye piece 3.The clear view of cross hairs by lighting switch.

FIG 3.3.5 BOTTOM VIEW OF CASING

Fig 3.3.5 shows the plan of the tripod in which 1. The plate is consisting the centre hole with bubble tube. 2. The bolts are connected ranging pole and extension pipe 3. The legs are arranged to triangular ends.4. The adjusting screw is connected with bolts. 5. The extension pipe is connected between plate and Ranging pole.

FIG 3.3.6 SECTIONAL VIEW OF CASING

. Fig 3.3.6 shows the sectional view of the tripod in which 1. The extension bolt is connected to the extension pipe. 2. The clip is connection between the plate and legs. 3. The 25 mm legs are connected to clip. 4. The adjusting screws are used to releasing the smaller leg. 5. The 20mm legs are connected to intersecting the longer diameter pipe. 6. The steel shoes are sharpen to connect to the smaller pipe. 7. The extension pipe is connected between plate and Ranging pole. 8. The accurate level of the tripod is done by bubble tube in which 2 nos are located L shape. 9. The whole arrangement of leg is connected to the central plate. 10. The clip bolts are fixed along linearly connected between to the clips.

4. SUMMARY OF THE PROJECT:

• The adjustable prism cross staff consists the three set up of tripod legs, offset rod, casing. Each component is worked separated principles. The tripod legs are consisting the three legs which performing the adjustment in anywhere place of the field by adjusting screws. Offset rod is placed over the center hole of the plate tripod inserting towards the centering.

• Casing is a main component of the cross staff. It is used to obtaining the right angles by provision of the prisms. It contains the hollow circular plastic conduit with plain object vane and top and bottom prism. The prisms are two numbers are fixed above and below the plain object vane. The plain object vane is centrally placed to perpendicular of the casing. The prism is made by one mirror and the two no of glass are fixed by triangular principle. The prism is two numbers are used to alternate placing of viewing right and left of the objects.

• The glass portion of the prism are located in eyepiece and the plain object vane are consisting the small diameter straight pipe are closed by glass on two sides such as eye vane and object pieces.

• The objects are accurately aligned by use of cross hairs. The cross hairs are used to fix the coincide the objects on eye piece. The whole setup of the casing is fixed on the offset rod. Offset rod is a made on aluminum pipe with sharp steel shoe at bottom end. The shaded color of the offset rod similar to ranging rods. The red and white colors are coated 9^" height in between these colors.

• The cross staff is viewed in day time the objects are clearly invisible due sun light. The illumination of the sunlight is neglected by use of the lightings. The LED light is fixed along the lateral direction of the casing. The eye piece of the glass is partially closed by insulation red tape. In case of ON the light which provides the cross a hairs and objects are clear visible.

• The centering of the tripod is achieved by sprit level. Sprit level is attached to the top plate of the tripod legs at 90°. The procedures involved similar to the normal cross staff offsetting. The proposed offsets are fixed the station A, B, C from survey station O. The cross staff components are assembled to fix and adjusting over the centering by adjusting screws. The Tripod legs are centrally fixed by the sprit level.

• The survey station O is fixed accurately which starting the offsets of the A, B, C objects. The station A are located straight of the line of sight for required distance. The A station are fixed by plain object vane are used to fix by cross hairs. The station B, C is right and left of the survey station O. The top prism is viewed to fix in order to coincide to the plain object vane at right side of the survey station. Again the procedure is repeated to the bottom prism which fixes the left side of the survey station. The above objects are A, B, C are coinciding on the eye piece.

• Finally, we have check the setting out of the above stations are checked by 3, 4, 5 rule.

ADVANTAGES

FIG 5.1 SURVEY STATION

• The ranging is done by preliminary method of direct ranging by use of ranging rods. But this cross staff is simplifying the direct ranging. Also provides the accuracy of the ranging by the plain object vane glass.

• The distance measured right or left of the chain line to locate the tie line.

FIG 5.2 FOUNDATION MARKING

• The offset measuring for proposed or existing building in which the survey station to tie stations are precise.

FIG 5.3 SETTING OUT OF OFFSET

• Stack out the Foundation marking in all structures such as buildings, industries, etc., • The framed and load bearing structure are must be most precise setting out or stack out by the cross staff. It is also performing accurately and quickly.

• Locate the objects at 180 degrees per person.

FIG 5.4 TRIPOD CENTERING

• The main station to subsidiaiy stations are marked and setting out by one person due to the casing fixtures. When the instrument fixing the survey point of the line is done by adjusting screws and offset rods.

• Locate the instrument over centre line (Centering).

FIG 5.5 SPRIT LEVEL

• The sprit levels are fixed over the tripod connecting plate. It gives the proper lever on anywhere of the field.

• Tripod legs are accurately leveled by sprit level.

FIG 5.6 LIGHT FITTING

• Eliminate the illumination from sunlight by provision of lightings.

• In day time the sun light is shaded the objects on the glass of the casing.

The problem is reduced by the provision of LED lightings.

FIG 5.7 CROSS HAIRS

The objects are aligned to fit the center tine by cross hair.

• The cross hairs are located on the three eye pieces at lateral direction. It is accurately fixed by the 3, 4, 5 rule.

FIG 5.8 PRISM SQUARE ERROR

• Eliminate the errors and misalignment of the prism square. 6. ESTIMATION OF THE PROJECT:

7. RESULT AND CONCLUSION:

The Temate cross staff is used for land survey in our college field. Our college construct on the hilly region in which the cross staff are very useful to marking the ground boundaries, running tracks, Survey laboratory, etc., It gives the accurate level results which get the successful results. The project is newly invented on the linear surveying measurements.

The outcome of the project is overcome the disadvantages of normal type of cross staffs. The demerits of the previous attempt’s was solved by us as merits. Hence the project has provided us lots of knowledge about surveying techniques.

Claims

1. The core components are the following;

a. Light emitting diode

b. Cross hair

c. Adjustable leg

d. Optical triangulation

e. Split level

f. Compass

g. Aluminium Tripod stand

h. Eye piece

i. HV Battery 5V

2. To increase accuracy of range, light emitting diode is used to reduce the variations which is switched on by a ON/OFF switch.

3. Triangle optical is embarked with a cross hair on x,y and z axis

perpendicular to each other on a 90degree angle.

4. Leg adjustable with a two split level to adjust with irregular topography made up of aluminium material.

5. Compass to denote the direction of the point and notable.