35 of said rectangular tightening nut 34 has a notch 36 formed therein which opens into the longitudinal edge 35 and is adapted to receive a guide and stop member 37 projecting from one of the longitudinal walls 38 of said rectangular recess 33 thus preventing any untimely rotation of the tightening nut 34 a pair of tapped holes 39 40 are formed through this nut 34 and the distance 41 between centres of the holes 12 13 formed through the body 2 to permit a bidirectional adjustment of the striker plate 1 the face plate 21 comprises at the level of the fastening members securing the body 2 of striker plate 1 to the rectangular tightening nut 34 polygonal apertures 43 44 of which the distance between centres 45 is equal to the above defined distances between centres 41 42 these apertures 43 44 have a substantially square configuration and their four corners 46 47 48 49 are rounded as shown at 50 51 52 53 with a radius depending on the diameter of the fixing members not shown whereas the difference between the length 54 of the sides 55 56 and the diameter of the fixing members not shown depends on the desired amplitude of vertical and or horizontal adjustment of the position of the striker plate for this purpose the height 57 and width 58 of face plate 21 are inferior to the height 59 and width 60 of recess 11 thus providing spaces 61 62 of a width 63 64 corresponding to the amplitude of said adjustment respectively on the other hand the height 65 and width 66 of the rectangular tightening nut 34 are smaller than the height 67 and width 68 of recess 33 of face plate 21 thus providing spaces 69 70.