scope:

INTRODUCTION

This module describes the design of lever frames and associated interlocking. See also the mechanical handbook, NR/GN/SIG/19014.

Although this module is not in itself mandatory, use of mechanical locking will satisfy the principles given in Section 2 of this Part of the Standard if the appropriate sections are complied with. The application of the principles and requirements to mechanical and electro-mechanical interlockings are summarised in Sections 4 and 5, respectively.

The design details required for a mechanical interlocking are described in NR/L2/SIG/11201, Module A2. Examples relating to the typical layout shown in Figure:10 are given in Figures:11 to 14.

Most of the locking terms used in this Module are illustrated in the figures. Where other former regional terms are found describing these items, care should be taken to avoid ambiguity. For instance, locks and notches are also known as nibs (or wedges) and ports. Tappets can be known as swords, irons or blades. Locking bars can be referred to as bridles, and studs as drivers.