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Topic: Tribrach (instrument)

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	Tribrach (Site not responding. Last check: 2007-10-18)
		A tribrach is a metrical foot used in formal poetry.
		A tribrach is used to iteratively and simultaneously realize the dual requirements placed on a theodolite mounted for measurement over a benchmark: that it be centered and levelled.
		Usually the tribrach also contains a forced centering mechanism, allowing the theodolite to be replaced by a target, optical plummet or other instrument to the same position with sub-mm precision, by just loosening and re-tightening a locking screw.
	www.guajara.com /wiki/en/wikipedia/t/tr/tribrach.html (262 words)

	Tribrach - Wikipedia, the free encyclopedia
		Tribrach (poetry), a metrical foot of three short syllables.
		Tribrach (instrument), a device used in surveying for leveling and centering.
		This is a disambiguation page: a list of articles associated with the same title.
	en.wikipedia.org /wiki/Tribrach (89 words)

	Survey Manual Version January 2000 (Site not responding. Last check: 2007-10-18)
		Whenever possible, select instrument stations where operation is not dangerous to the instrument operator, the crew, or the instrument. Select stable ground for the tripod feet. Do not set an instrument closely in front of, or behind, a vehicle or equipment which is likely to move. Take a safe route to all setups.
		Tribrachs are an integral part of the precision equipment and should be handled accordingly. They should be transported in separate compartments or other containers to prevent damage to the base surfaces, bulls eye level, and optical plummet eye piece. Over tightening of the tripod fastener screw can put undue pressure on the leveling plate.
		The tribrach mounted traverse target sets are recommended for all baseline traverse surveys, and other control surveys, when they are available. The tribrach contained optical plummet and target configuration provide the most positive daytime sight available. Several illumination kits, consisting of a light bulb case and battery case, are available for nighttime surveys.
	www.state.nj.us /transportation/eng/documents/survey/Chapter5.htm (2713 words)

	WSLS - Wisconsin Society of Land Surveyors
		If the circular level in a tribrach is out of adjustment it will become apparent when you place an instrument in it and then have to move the foot screws quite a bit to get accurately level.
		Tribrach adjustments are totally independent; changing the adjustment of the level vial has no effect whatever on the adjustment of the optical plummet.
		In theory the plane of the tribrach is the flat surface on which base of the instrument rests.
	www.wsls.org /tribrach.htm (807 words)

	Wikipedia: Tribrach
		In surveying science, a tribrach means an instrument attachment plate containing three thumbscrews (see theodolite).
		Both metal plates making up the tribrach have a large circular hole in the center, through which goes the attachment screw of the theodolite.
		In this way, it is possible to mount the instrument firmly, but freely (within some inches) choose the horizontal position of attachment.
	www.factbook.org /wikipedia/en/t/tr/tribrach.html (251 words)

	Chapter 5
		As optical instruments progressed, the development of optics allowed the telescope to become shortened to the point that the optics could be rotated 360° horizontally.
		An instrument constant can be either positive or negative and may change due to the phase shifts in the circuitry.
		The algebraic sum of the instrument and the prism constants are referred to as the total constant.
	www.globalsecurity.org /military/library/policy/army/fm/3-34-331/ch5.htm (7122 words)

	SECO Manufacturing Company, Incorporated -- www.surveying.com
		Place the tribrach to be adjusted on top of the adjuster so that it is upsidedown looking at the target on the ceiling.
		Using the leveling screws of the bottom tribrach, point the crosshair of the tribrach being tested to coincide with the target.
		Place the #2002 in the tribrach and level the tribrach using the vial on the #2002.
	www.surveying.com /tech_tips/details.asp?techTipNo=12 (374 words)

	WSDOT Survey (Site not responding. Last check: 2007-10-18)
		However, to assure that the measuring capabilities of an instrument have not significantly deteriorated, a known distance of high accuracy or, preferably, a sequence of distances forming a calibration range or base line is required.
		For a total station the instruments EDM should be checked not only directly to the calibrated baseline itself, but also in conjunction with the methods that will be used to perform the survey such as with a data collector and downloading the data into a survey processing surveying program.
		If the instrument and reflector are at a height of 1.5 meters (4.92 ft.) over the marks and one division out of level, then the equipment can be off the point by 0.14 mm (0.0005 ft.) and 0.43 mm (0.0014 ft) respectively, or a total of 0.57 mm (0.0019 ft.).
	www.wsdot.wa.gov /eesc/CAE/survey/baseline_calibrations.htm (2648 words)

	Instrument Maintenance - Archives - Point of Beginning (Site not responding. Last check: 2007-10-18)
		The instrument is used on jobsites where it is exposed to blowing dust and inclement weather.
		The minor cleaning involves cleaning the tribrach, the tangents, the focus assemblies, the exterior of the instrument, as well as the case and accessories.
		The tribrach and tangents are removed from the instrument and disassembled.
	www.pobonline.com /CDA/Archives/1255f0b5ba0f6010VgnVCM100000f932a8c0____ (1275 words)

	FIIG T370 Index
		A small device consisting of a level vial or vials mounted in a bracket which is held against or fastened to a level rod to determine whether the rod is being held in a vertical position.
		An instrument used to establish the horizontal plane of a course line as in laying brick or stone walls, foundations, buildings, roads, etc. It consists of a lightweight pocket type level with hooks at each end for attaching on or hooking over a line.
		It consists of a graduated vial with a liquid bubble and is attached to the rotor case of a gyrocompass.
	www.dlis.dla.mil /fiigdata/T3700/ainindex.htm (851 words)

	CFJ-IIB W.Measure 8304
		This instrument is clearly not a derivative of the Warren-Knight instrument.
		I suspect that this instrument was influenced by the Russian AWT Instrument and the Soviet ATK-2 Instrument.
		A unique (shared with the AWT instrument) aspect of this theodolite is that the reticule assembly is mechanically connected to the body of the theodolite not to the eyepiece tube.
	www.csulb.edu /~mbrenner/cfj-iib_w_measure_8304.htm (343 words)

	Tooling Stands
		Cast iron trivets are a convenient means of setting up instruments on surface plates, machine tables, the floor, or any place where the line of sight is close to the supporting surface.
		Controls: The instrument mount is raised and lowered by a recirculating ball nut lead screw.
		Raising and lowering of the instrument mount is controlled by means of a capstan with pinion gear, ratchet and clamping lever.
	www.mindspring.com /~optical/bstands.htm (1098 words)

	Descripson of the WILD Theodolites and Accessories
		The Wild RKI Self-Reducing Alidade is a robust, compact and easily-handled instrument which combines a telescopic alidade, a self-reducing Tacheometer and a convenient plotting device, with a large selection of interchangeable scales, for the immediate and neat plotting of detail by bearing arid distance.
		Particularly attractive is the ability to set up the transmitter- antenna unit in its tribrach on a tripod or observing pillar and, by means of an extra long cable, to operate the instrument from the shelter of a vehicle.
		Being detachable from the tribrach the ZNL (which has a plumbing accuracy of 1/30 000) can be centered over or under the required point and then replaced by the theodolite with guaranteed forced-centering.
	www.wild-heerbrugg.com /theodolites2.htm (2696 words)

	Total Distance Station and Surveying
		Supporting the instrument with one hand, screw the centering bolt on the bottom of the tripod into the bottom of the instrument so it is secured.
		Move the instrument so that the plate level #22 is parallel in a line between leveling screws A and B #9.
		Center the instrument over the surveying point: Slightly loosen the centering bolt (see step 2 from the "Centering the Tripod" section); and, looking through the optical plummet eyepiece #17, slide the instrument over the head of the tripod so that the instrument is exactly centered over the target.
	www.cst.cmich.edu /users/franc1m/esc334/exercises/total_distance_station_and_survey.htm (1568 words)

	0301
		It is the simplest form of levelling instrument consisting of two main parts: the tribrach and the telescope.
		The tribrach has four foot screws which may be rotated to allow the telescope to give the required horizontal line-of-sight.
		The level is fitted with a long sensitive bubble tube attached to the top of the telescope which enables the line-of-sight (line of collimation), as defined by the cross hairs, to form a horizontal line which is perpendicular to the direction of gravity at that point.
	www.gmat.unsw.edu.au /currentstudents/ug/projects/f_pall/html/l1.html (353 words)

	GIAA Mailbag: On Tribrachs and Phase Error with Targets - Archives - Point of Beginning (Site not responding. Last check: 2007-10-18)
		The wobbling or “rocking” you experience is due to wear on the instrument’s base or the contact points, or movement of the contact points on the tribrach.
		On many tribrachs, as this mechanism pulls the instrument or target down onto the contact points, it may cause a slight rotation of the instrument or target.
		As the distance between the instrument and the target increases, the lit part of the target or the shaded part of the target, depending on observing conditions, including background, may become so dominant that the observer erroneously aligns the cross hairs with the apparent width of the target rather than its true width.
	www.pobonline.com /CDA/Archives/b492be768d0f6010VgnVCM100000f932a8c0____ (748 words)

	GPS Survey Equipment
		Basic instrumentation for a GPS network survey includes multiple sets of receivers, antennas, fixed-height tripods, and meteorological instruments.
		The compatibility of mixing different instrument models or brands should be demonstrated by performing a validation survey.
		Tribrachs used shall be of suitable quality and condition for high-accuracy surveys.
	www.ngs.noaa.gov /PROJECTS/GPSmanual/equipment.htm (842 words)

	810 Portable Stand
		The stand comes with a set of short legs, a set of long legs, and a set of trivet points that may be mounted directly in the three sockets on the tribrach plate, for setting the stand almost directly on the floor or other work surface.
		Almost anything will fit on it because it is equipped not only with the 3½" x 8 standard external instrument mount threads, but also our dovetail receptacle and the 2.825" x 20 internal thread found on many of our intermediate tubes.
		Below left: The 810 stand assembled with the short instrument mount tube and the short legs.
	www.brunson.us /Products/810.asp (434 words)

	Levelling - A Tutorial
		The instrument is secured to the tripod head using the tripod screw.
		Spherical level is a bubble spirit level attached to the tribrach and referenced to the axis of the telescope.
		The instrument can be rotated by hand, using the 'gun sight' on top of the telescope to find the staff.
	www.filter.ac.uk /database/getinsight.php?id=45&seq=6 (315 words)

	Portland Precision Instrument & Repair Co.
		Topcon tribrachs are recommended for accurate plumbing of Topcon total stations, theodolites, reflector systems and other accessories.
		Topcon tribrachs feature a special US Patented optical system that allows for quick and accurate checking and adjustment of the optical line of sight.
		This is accomplished simply by using the optical plummet in a Topcon instrument's alidade in conjunction with the optical plummet in the tribrach.
	www.portlandprecision.com /survey_accessories_prisms.html (161 words)

	Electronic Surveying Measurement (Site not responding. Last check: 2007-10-18)
		Mounted on a tribrach or to a theodolite.
		The instrument is turned on to insure it is in good working order.
		The height of the prism and instrument are measured and recorded.
	class.et.byu.edu /ce113sp/notes/Chapter5.html (569 words)

	Watts Mark V
		Other changes from the MK IIII include the relocating of a bubble level from the top of the tribrach base to the body of the theodolite, and the addition of a key lock on the wood case of the instrument.
		The instrument pictured, produced in 1968, was in the service of a British Military Unit.
		There are two pins on the tip of this instrument that serve as contacts to an attachable battery case.
	www.csulb.edu /~mbrenner/watts2.htm (416 words)

	Field Supplies Tribrachs , Tribrach Adapters
		The base plate is a universal 5/8" x 11 with circular leveling vial that has a sensitivity of 10'/2mm.
		This Zeiss/Wild rotating tribrach adapter with a removable center adapts retro prisms to Wild-type tribrachs and has removable Zeiss plug for adapting prisms to Zeiss tribrachs.
		This rotatable friction top adapter allows the prism to be pointed after installation in the tribrach.
	www.instrumentsales1.com /online-store/scstore/fs-15.htm (188 words)

	Tribrach - TheBestLinks.com - Poetry, OED, Metrical foot, Short syllable, ... (Site not responding. Last check: 2007-10-18)
		Tribrach - TheBestLinks.com - Poetry, OED, Metrical foot, Short syllable,...
		Tribrach, Poetry, OED, Metrical foot, Short syllable, Theodolite, Level...
		When tightened, this screw firmly attaches the theodolite, placed atop the tribrach, to a flange pressing against the bottom surface of the tribrach.
	www.thebestlinks.com /Tribrach.html (286 words)

	Leica Total Station Field Procedures Document
		Remove Tribrach (13) from instrument by rotating the fl lever on the Tribrach counterclockwise until freed from the Tripod.
		Using the three foot-screws (1), level the Tribrach (13) using the bullseye level on the Tribrach.
		Remove the Station and Tribrach by unscrewing the large metal hand screw in the center of the tripod.
	www.geology.iupui.edu /academics/classes/G303/Maps/procedures.htm (1021 words)

	0418
		The instrument features a slot for an electronic data recording card.
		The instrument comes with two padded plastic transport cases, one for use with mounted gyro bridge (350 x 280 x 490 mm) and one for the original instrument (350 x 280 x 450 mm).
		The instrument has a fl gunsight and belongs to the second series of TC1600 manufactured, with an EDM unit length of 3 m.
	www.gmat.unsw.edu.au /currentstudents/ug/projects/f_pall/html/e18.html (138 words)

	Forensicmapping.com - Training
		If your instrument is equipped with a laser plummet (shown above) and once the Instrument is leveled, the precise R.P. location should be marked or otherwise noted.
		Once you have leveled the Instrument, it is then time to Zero-SET the Instrument towards a northerly, compass direction, a topic covered elsewhere.
		It is fair to note that so long as the Instrument is leveled within a reasonable time ~ that it is leveled to the extent that it permits distance measurements, no matter the procedure to get it level, you should be ready to commence your scene diagramming efforts.
	www.forensicmapping.com /sceneworks/levelingtips.htm (628 words)

	Seco Tripods (Site not responding. Last check: 2007-10-18)
		It fits all ‘wild-type’ tribrachs with 5/8 x 11 mounting stud.
		The base will accept any 5/8 x 11 instrument and features a precision brass slow-motion tangent screw.
		It’s ideal for all instruments, total stations, robotics, and GPS gear.
	shopping.netsuite.com /s.nl/c.ACCT107460/sc.2/category.95/.f (226 words)

	[No title] (Site not responding. Last check: 2007-10-18)
		You need to do this for the first setup in case you move the instrument or power off before you're done collecting data here.
		IMPORTANT - make sure the bottom silver piece of the AE is tight against the tripod, tribrach adapter or staff - and does not rotate during use.
		If a second instrument point is required, shoot it last and store it using the Point button.
	www.lasertech.com /ftp/techdocs/tutorials/AE_QM4_qref.txt (409 words)

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