ISO INTERNATIONAL STANDARD 12858-3 First edition 2005-02-01 Optics and optical instruments Ancillary devices for geodetic instruments Part 3: Tribrachs Optique et instruments d'optique -Equipements annexes pour les instruments géodésiques Partie 3:Embases Reference number ISO 12858-3:2005(E) ISO @ ISO 2005 ISO12858-3:2005(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In accepts no liability in this area Adobeis atrademarkofAdobeSystems Incorporated. the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below. ? ISO2005 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 IsO's memberbody in the country of the requester. ISO copyright office Case postale 56.CH-1211Geneva 20 Tel. + 4122 749 01 11 Fax + 41 22 749 09 47 E-mail [email protected] Web www.iso.org Published in Switzerland ii ISO 2005-All rights reserved ISO 12858-3:2005(E) Contents Page Foreword iv Introduction 1 Scope 2 Normative references 3 Terms and definitions 4 Type W tribrachs. 4.1 Nomenclature .. 4.2 General features Dimensions 5 Type Z tribrachs . 5.1 Nomenclature .... 5.2 Generalfeatures Dimensions 6 Requirements 6.1 General... 6.2 Connection between the tribrach and the tripod. 6.3 Torsional rigidity.. 6.4 Foot screw.. 10 6.5 Protectionfromcorrosion. 10 6.6 Clampknoborclampscrew 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 stability... 11 Iso2005-All rightsreserved ili ISO 12858-3:2005(E) Foreword 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 International Standards are drafted in accordance with the rules given in the ISO/lEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as ar International Standard requires approval by at least 75 % of the member bodies casting a vote. 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 Geodeticandsurveying instruments. Iso 12858 consists of the following parts, under the general title Optics and optical instruments Ancillary devicesforgeodeticinstruments: Part1:Invarlevelling staffs Part 2: Tripods 一 Part 3:Tribrachs iv ISO 2005- All rights reserved ISO12858-3:2005(E) Introduction ISO12858 Additional parts, covering further ancillary devices, may be added to IsO 12858 as the need arises @ISO2005-All rights reserved V INTERNATIONAL STANDARD ISO12858-3:2005(E) Optics and optical instruments Ancillary devices for geodetic instruments Part 3: Tribrachs Scope connectionoftheinstrument'sbodywithitsbase The requirements in this part of isO 12858, however, do not guarantee the full interchangeability of the instrument's 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 tribrach in use, categorized in this part of sO 12858 as Types W and Z. This part of isO 12858 is applicable to tribrachs which are used for levels, theodolites, tacheometers, GPS e