ISO 8624-2011 pdf free download

ISO 8624-2011 pdf free download.Ophthalmic optics Spectacle frames Measuring system and terminology
Optique ophtalmique — Mon tures de lunettes — Système de mesure et terminologie.
NOTE For spectacle frames having a significant face form angle (A.13), the boxed centre distance shall be measured between the boxed centres (2.1) marked on the back surfaces of lenses of appropnate base curve fitted to the frame. See FIgure 4.
2.5
distance between lenses
horizontal distance between the nasal vertical sides of the rectangular boxes Which circumscribe the right and left lens shapes (A.1O)
See Figure 1.
NOTE Former users of the obsolete datum system should note that this is the datum measurement minimum between lenses”
2.6
overall length of side
I
length from the intersection of the dowel screw’s axis with the median plane of the joint to the end of the side and parallel to the centreline of it, the drop having been straightened
See Figure 2.
NOTE For sides without a joint, the side should be held open at (90 ) to the front or to that part of the side that is intended to be attached to the front, and the length measurement is from the end of the side to the front less 10 mm. See Figure 3.
3 Measuring system
The measuring system for spectacle frames shall be in accordance with Figures 1 to 4, as defined in Clause 2.
If codes are used in spectacle frame documentation, the symbols given for the terms defined in Clause 2 shall be employed.
The measuring system comprises several horizontal and vertical dimensions and reference points. The knowledge of these is necessary for the manufacturing, ordering and adjustment of spectacle frames as well as for the exact mounting of spectacle lenses into spectacle frames.
The measuring system is based on the boxed lens (boxing) system, which uses a rectangle tangential to the lens shape as the basis for the determination of the dimensions of the spectacle front. The upper tangent is common to both lens shapes and shall be regarded as horizontal, except in the case of spectacle frames having a significant face form angle, for which the line touching the uppermost edges of the right and left lens shapes shall be regarded as horizontal.ISO 8624-2011 pdf free download.