1、 Reference number ISO 12858-3:2005(E) ISO 2005INTERNATIONAL STANDARD ISO 12858-3 First edition 2005-02-01 Optics and optical instruments Ancillary devices for geodetic instruments Part 3: Tribrachs Optique et instruments doptique quipements annexes pour les instruments godsiques Partie 3: Embases IS
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5、iven below. ISO 2005 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs memb
6、er body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2005 All rights reservedISO 12858-3:2005(E) ISO 2005 All rights reserved iiiContents Pa
7、ge Foreword iv Introduction v 1 Scope 1 2 Normative references. 1 3 Terms and definitions. 1 4 Type W tribrachs . 2 4.1 Nomenclature 2 4.2 General features Dimensions 3 5 Type Z tribrachs 6 5.1 Nomenclature 6 5.2 General features Dimensions 7 6 Requirements 9 6.1 General. 9 6.2 Connection between th
8、e tribrach and the tripod. 9 6.3 Torsional rigidity. 9 6.4 Foot screw. 10 6.5 Protection from corrosion 10 6.6 Clamp knob or clamp screw 10 6.6.1 Type W 10 6.6.2 Type Z. 10 6.7 Circular level 10 7 Designation and marking. 10 Annex A (informative) Recommendations for Type W tribrachs with improved st
9、ability. 11 ISO 12858-3:2005(E) iv ISO 2005 All rights reservedForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical com
10、mittees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
11、 International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft Internatio
12、nal Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be t
13、he subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 12858-3 was prepared by Technical Committee ISO/TC 172, Optics and photonics, Subcommittee SC 6, Geodetic and surveying instruments. ISO 12858 consists of the following parts, under the
14、general title Optics and optical instruments Ancillary devices for geodetic instruments: Part 1: Invar levelling staffs Part 2: Tripods Part 3: Tribrachs ISO 12858-3:2005(E) ISO 2005 All rights reserved vIntroduction ISO 12858 consists of a series of parts which detail specifications for ancilliary
15、devices to be used with geodetic instruments in surveying. This third part specifies requirements for Tribrachs. Additional parts, covering further ancillary devices, may be added to ISO 12858 as the need arises. INTERNATIONAL STANDARD ISO 12858-3:2005(E) ISO 2005 All rights reserved 1Optics and opt
16、ical instruments Ancillary devices for geodetic instruments Part 3: Tribrachs 1 Scope This part of ISO 12858 specifies the most important requirements of tribrachs used in geodesy for the connection of the instruments body with its base. The requirements in this part of lSO 12858, however, do not gu
17、arantee the full interchangeability of the instruments body with tribrachs of different manufacturers, but give the detailed specifications of the clamp system to ensure the reliable mounting and clamping without prejudicing their performance and their usefulness. There are mainly two types of tribr
18、ach in use, categorized in this part of ISO 12858 as Types W and Z. This part of ISO 12858 is applicable to tribrachs which are used for levels, theodolites, tacheometers, GPS equipment, EDM instruments and in combination with targets, reflectors, antennae etc. 2 Normative references The following r
19、eferenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 2768-1, General tolerances Part 1: Tolerances for linear and
20、 angular dimensions without individual tolerance indications ISO 9849, Optics and optical instruments Geodetic and surveying instruments Vocabulary ISO 12858-2:1999, Optics and optical instruments Ancillary devices for geodetic instruments Tripods 3 Terms and definitions For the purposes of this doc
21、ument, the terms and definitions given in ISO 9849 apply. ISO 12858-3:2005(E) 2 ISO 2005 All rights reserved4 Type W tribrachs 4.1 Nomenclature The names of the most important parts of a Type W tribrach are given in Figure 1. Key 1 pivot 2 hook 3 guide hole 4 circular level 5 socket 6 clamp knob 7 f
22、oot-screw cap 8 tribrach plate 9 foot-screw knob 10 base plate 11 fixing star Figure 1 Nomenclature for Type W tribrachs ISO 12858-3:2005(E) ISO 2005 All rights reserved 34.2 General features Dimensions The mechanical properties and the base part of instruments shall comply with the values given in
23、Table 1. The shape of the tribrach and the body as shown in Figures 2, 3 and 4 are examples for information only. Table 1 Mechanical properties of Type W tribrachs Dimensions Description Symbol Unit Nom. Tol. Figure No. Centring diameter A mm 80 0,02 0,07 2 Pitch circle diameter B mm 65 2 Pitch circ
24、le angle C 120 2 Orientation tolerance of hook flank a mm 0,1 2 Location tolerance of hook flank b mm 0,2 2 Lead angle of hook flank D 95 3 Angle of hook flank E 120 3 Radial height of root F mm 1 0,1 3 Working position of bearing flank (58) G mm 3,5 3 Axial height of bearing flank (58) H mm 7,88 3
25、Flank location tolerance c mm 0,04 3 Angularity of flank d mm 0,025 3 Diameter of hook I mm 11 0 0,05 3 ISO 12858-3:2005(E) 4 ISO 2005 All rights reservedKey 1 hook (see Figure 3) NOTE See Table 1 for explanation of symbols. Figure 2 Vertical axis holder of the instrument NOTE See Table 1 for explan
26、ation of symbols. Figure 3 Details of the hook ISO 12858-3:2005(E) ISO 2005 All rights reserved 5Dimensions in millimetres NOTE See Annex A for explanation of symbols. Figure 4 The tribrach dish and fixing star ISO 12858-3:2005(E) 6 ISO 2005 All rights reserved5 Type Z tribrachs 5.1 Nomenclature The
27、 names of the most important parts of a Type Z tribrach are given in Figure 5. Key 1 pivot 2 tribrach plate 3 foot-screw knob 4 base plate 5 clamp screw 6 pivot hole 7 circular level Figure 5 Nomenclature for Type Z tribrachs ISO 12858-3:2005(E) ISO 2005 All rights reserved 75.2 General features Dim
28、ensions The mechanical properties and the base part of instruments shall comply with the values given in Table 2. The shape of the tribrach and the body as shown in Figures 6, 7, 8 and 9 are examples given for information only. Table 2 Mechanical properties of Type Z tribrachs Dimensions Description
29、 Symbol Unit Nom. Tol. a Figure No. Pivot diameter A mm 34 h8 6 Constriction diameter B mm 32,5 6 Pivot length C mm 33 6 Constriction length D mm 17 0,2 0 +6 Pivot partial length E mm 11 0 0,2 6 Tolerance of the orthogonality a mm 0,01 6 Phase angle F 60 6 Contact diameter G mm 45 7 Distance clamp s
30、crew H mm 14 0,2 7 Total pivot hole length I mm 33,5 7 Free diameter pivot hole K mm 35 8 Function diameter pivot hole L mm 33,96 0,04 0 +8 Max. distance to interface N mm 48,2 9 Max. width for an interface O mm 35 9 aFor unspecified tolerances: ISO 2768-m. NOTE See Table 2 for explanation of symbol
31、s. Figure 6 Pivot ISO 12858-3:2005(E) 8 ISO 2005 All rights reservedNOTE See Table 2 for explanation of symbols. Figure 7 Pivot hole NOTE 1 See Table 2 for explanation of symbols. NOTE 2 The shown solution is one of different possibilities. Figure 8 Pivot hole ISO 12858-3:2005(E) ISO 2005 All rights
32、 reserved 9NOTE See Table 2 for explanation of symbols. Figure 9 Space for power and data interface 6 Requirements 6.1 General The tribrach shall be suitable for levelling of surveying instruments by using the levelling mechanism such as levelling screws; centring of surveying instruments with its c
33、entring telescope or through a hole. Material, machining, surface treatment and assembling of the tribrach are left to the manufacturers discretion. 6.2 Connection between the tribrach and the tripod A 5/8 in (inch) nut thread shall be provided in the instrument base plate as specified in ISO 12858-
34、2:1999, 6.3. 6.3 Torsional rigidity The tribrach shall be capable of absorbing, without lasting deformation, the torsion which occurs when the instrument is used. When testing the torsional rigidity, set up and fix the instrument with the tribrach on a hard rigid stand (instead of on a tripod), adju
35、sting the cross-hair on a collimator or any target, applying a torque similar to the one which will be exerted on the tribrach when in the intended use (e.g. 0,3 Nm, 0,5 Nm, etc.) by pushing the side of the instrument in a clockwise direction. After releasing the torque, measure the remaining displa
36、cement in the horizontal angle. Then, repeat the same procedure in an anticlockwise direction, and read the remaining displacement. ISO 12858-3:2005(E) 10 ISO 2005 All rights reservedIt shall be the responsibility of the user to ensure that the tribrach has sufficient torsional rigidity to be compat
37、ible with the accuracy of the instrument. 6.4 Foot screw The levelling mechanism, such as foot screws, shall enable a smooth and fine levelling operation. 6.5 Protection from corrosion All components shall be resistant to, or protected from corrosion. 6.6 Clamp knob or clamp screw 6.6.1 Type W The t
38、ribrach shall be equipped with a clamp knob or corresponding device which turns the fixing star and which operation shall be smooth to assure full function of the clamping mechanism. 6.6.2 Type Z The tribrach shall be equipped with a clamp screw which fixes the pivot without destroying the pivot sur
39、face. 6.7 Circular level The tribrach can be equipped with a circular level. This circular level shall be built at a position on the tribrach that it can be easily seen. 7 Designation and marking The marking shall indicate at least the name or trademark of the manufacture (or the responsible supplie
40、r) of the tribrach. The tribrach may be marked additionally on the flat face of the socket with the designation as shown below for the example of a Type W tribrach. ISO 12858-3:2005(E) ISO 2005 All rights reserved 11Annex A (informative) Recommendations for Type W tribrachs with improved stability A
41、 Type W tribrach with mechanical properties complying with the values given in Table 1 ensures a reliable mounting and clamping without prejudicing its performance and usefulness. For improved stability, however, it is recommended to observe the additional mechanical properties as given in Table A.1
42、. Table A.1 Additional mechanical properties for Type W tribrachs with improved stability Dimensions Description Symbol Unit Nom. Tol. a Figure No. Centring diameter J mm 80 0,03 0 +4 Axial height of working flank of fixing star (58) K mm 7,88 4 Lead angle (58) Pitch P= 16 mm/360 5,02 4 Outer diamet
43、er of fixing star L mm 61 0,3 4 Flank angle of fixing star M 30 4 Angularity of flank angle e mm 0,025 4 Guide hole diameter N mm 13 4 Guide hole diameter O mm 11 0,2 0,05 + +4 aFor unspecified tolerances: ISO 2768-f. ISO 12858-3:2005(E) ICS 17.180.30 Price based on 11 pages ISO 2005 All rights reserved
