154 



BOOKCASE Bolt. 



XIII. 



Description of a very useful Bolt for Bookcase Doors. Bif 

 Mr. Peter Herbert, No. 33, Bozo Street^ Govent 

 Garden*. 



ttTolti"°^ ™*-^' HERBERT presented to the Society a model of his 

 ., ' invention. He intended it for a library book-case bolt, to 



y, / facilitate the opening of both doors at once, and to secure 



"'^■■A\^.: *hesame, without the trouble of bolting two bolts in the 

 common way. It will do for wardrobes, French casements, 

 or folding sash doors, and will also make a good sash fasten- 

 ing, if let into the bottom sash, with a small brass knob to 

 slide as common ; it would bolt in the frame by the side of 

 the sash cord, both sides at once ; and he can also make 

 it answer sundry other useful purposes if required. 



Reference to the Engraving of Mr. Peter Herbert's Bookcase 

 Bolt, Plate IF. Fig. 2. 

 Description. R^ ^ pjg^ 3^ represents the two stiles of the doors of a 

 folding bookcase. 

 M, the key-hole of a lock with two bolts, which are more 

 clearly shewn at Fig. 3, where the back of the lock N 

 shews the two bolts of the lock pressing back a sliding 

 piece, O ; on the front part of this sliding piece in 

 Fig. "-2, two small friction rollers are placed at P, in 

 the act of pressing against two levers, crossing on one 

 common fulcrum R, to each end of which shorter 

 levers, S S, above and below are connected by joints. 

 These short levers act' upon two long bolts, whose ex- 

 tremities are shewn at T T, having each a helical spring 

 at V, V. In the state as engraved, the doors are locked 

 and bolted. 

 On drawing back the bolts of the lock by means of the 

 key, the helical springs V V press against the plates U U, 

 through which the long bolts pass; they force back tiie 

 long bolts and sliding piece O, and allow both the doors to 

 open. 



* Sac. Art. i8o6. Ten guineas were given for this improvement, 



