GB578524A - A new or improved lock and key comprising indicator mechanism of the position of thelock on withdrawal of the key - Google Patents

Abstract

578,524. Keys. MEFINA SOC. ANON. Dec. 6, 1943, No. 20355. Convention date, Nov. 4, 1942. [Class 44] A flat type key has an indicator device arranged within the flat handle to show whether its last use was for locking or unlocking. As shown, the indicator comprises a cranked lever 27 pivoted at 28 in a recess 22 in the key handle 19, the recess having a cover-plate 23. Registering apertures are formed at 24 in the key handle and cover plate, and a blind aperture or depression is provided at 2 in the recess 22. One arm 30 of the lever extends beyond the apertures and has a hump 31 adapted to snap into the recesses to maintain the lever in each of its extreme positions. The lock, shown of rotating barrel type has a drum 12 with outer and inner end plates 13, 14 spaced apart. These plates have diametrically disposed embossments 17, 18 respectively, projecting into the space between the plates and serving to oscillate lever 27 as the key is rotated, the bosses being situated at opposite sides of the key-hole aperature 15, 16. The key has a notch between its handle 19 and bit 20, the other arm 29 of lever 27 extending into this notch as shown. When the key is fully home the notch registers with the plates 13, 14 with the end of arm 29 disposed in the space between them as in Fig. 2. When the key is given a complete clockwise rotation, Fig. 1, to effect locking, arm 29 is oscillated by the embossments 18, 17 in succession, the final movement given by embossment 17 leaving the lever in the full-line position, Fig. 2, with the arm 30 obturating the apertures at 24, to show that locking has been effected by the key. With anticlockwise movement to effect unlocking, the final movement to the lever is given by embossment 18, leaving the lever in the dotted-line position, Fig. 2, with the apertures at 24 uncovered. Alternatively, the indicator may be governed by cams or a helical groove, and may be arranged to slide instead of rocking.