ISO/TS TECHNICAL SPECIFICATION 19837 First edition 2018-03 Safety of machinery - Trapped key interlocking devices Principles for design and selection Securite desmachines-Dispositifs deverrouillage a cle captive- Principesdeconceptionetsélection Referencenumber IS0/TS19837:2018(E) ISO @IS0 2018 IS0/TS19837:2018(E) COPYRIGHTPROTECTEDDOCUMENT IS02018 All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting below or Iso's member body in the country of the requester. ISO copyright office CP 401 : Ch. de Blandonnet 8 CH-1214 Vernier, Geneva Phone:+41227490111 Fax: +41 22 749 09 47 Email: copyright@iso.org Website: www.iso.org Published in Switzerland ii @ IS0 2018 - All rights reserved IS0/TS19837:2018(E) Contents Page Foreword ..V 1 Scope ..1 2 Normativereferences 3 Terms and definitions 4 Symbolsandabbreviatedterms 5 Operatingprinciples andtypicalforms oftrapped keyinterlocking system ..5 5.1 General .5 5.2 Functional decompositionofatrappedkeyinterlocking system ..8 5.2.1 Isolation control.. .9 5.2.2 Intermediate transfer ..12 5.2.3 Access control. .13 6 General requirements for the design of Trapped Key interlocking device .13 6.1 ..13 General 6.2 Devicearchitectureandpositivemechanicalaction ..13 6.3 Endurance/Strength .14 6.3.1 General. .14 6.3.2 Resistancetoshockandvibration ..14 6.3.3 Mechanical life .14 6.3.4 Rotary actuators for access locks .14 6.3.5 Key retention. ..15 6.4 Systematics .15 6.5 Safety FMEA/FTA .15 6.6 ValidatingPerformanceLevel .15 6.7 Design to minimize defeat. ..16 6.7.1 General. ..16 6.7.2 Schemedesign forease ofuse. .16 6.7.3 Coded actuators. .16 6.7.4 Reproduction of keys .16 6.8 Clearances and creepage distances .17 6.9 Isolation control. .17 6.9.1 General. ..17 6.9.2 Direct mechanical action (Power interlocking) .17 6.9.3 Solenoid controlled switch .17 6.10 Access control .17 6.10.1 Escape release ..17 6.10.2 Emergency release ..18 6.10.3 Auxiliary release. ..18 7 System configuration .18 7.1 General .18 7.2 Key coding. .18 7.3 Keytransferplan .19 7.4 System selection .19 7.4.1 General. .19 7.4.2 Isolation control .19 7.4.3 Intermediatetransfer Access control. ..19 7.4.4 8 Information foruse. ..19 Annex A (informative) Examples of trapped key interlock devices .20 Annex B (informative) FMEA analysis -Typical failure modes for consideration in trapped keysystems .26 @ IS0 2018 - All rights reserved ii