adapted for being integrated into the frame front entension refer also to fig3 the hinge base 10 further comprises arm 12 with an extension bent in order to provide the pivot core 13 in order to assemble the parts the barrel 16 is fitted about the pivot core 13 and the temple coil 8 is fitted about the barrel 16 as an alternative the temple coil may be fitted about the barrel and the combination subsequently fitted about the pivot core fitting of the lug 11 into the frame front extension may be undertaken prior to the assembly of the hinge or subsequent to the assembly of the hinge as is considered convenient reference is now made to fig1 for a description of the barrel 16 fig1 shows a barrel according to a first embodiment in views from above from below from the front from the side in sections with the lines a u2014 a and b u2014 b and in isometric view as will appear the barrel basically comprises a member with an axial opening 17 and with an exterior thread comprising groove 19 and ridge 20 the groove 19 is rounded with a shape adapted to match the windings of the temple coil the thread basically comprises about 2 u00bd full revolutions the thread defines axis 25 which is the hinge axis the axial opening 17 has a rectangular section adjacent the top the recess is widened to etablish ledges 21 in the barrel lower portion there is a rounded recess 18 to one side in other embodiments the axial opening 17.