LOCKS. Dooa-Locas.—Yale Locks.—A late improvement. in Yale locks is the longitudi nal corrugation of the key and corresponding alteration of the escutcheon, the ping in which is provided with a key-way having corresponding corrugations throughout its entire length, so that the key and key-way engage with each other at all points. A section of the escutcheon and corru gated key is shown in Fig. 1. This construction prevents tilting of the key, and renders access to the tumblers more diffi cult.
The Yale front-door lock, shown in Fig. 2. is so made that during the day the latch-bolt may be operated from with out by a Yale corrugated key. At night the dead bolt may be locked from within by another Yale key of different bitting. and under the latter circumstances the Yale key first mentioned will act, first, to unlock the dead bolt by making a full revolution, and then by a further movement to retract the hitch. This arrangement gives the house holder an single Yale key to operate both latch and dead bolts at any time, rendering it impossible for him to be locked out at night, and at the same time permits the house to be locked from within by a key which can not be used by any one to effect an entrance. The nr rangement of parts will be understood by to Pig. 2. The dcad-bolt A is Made with n double tail and two dogging-levers B II connected together by a link. When either of the eseuteheon-plugs is rotated, the cam Con the end of the plug will depress its dog ging-lever and enter the corresponding talon, thus moving the bolt without regard to the position of the other dogging-lever. The lateh-bolt 0 is operated by the ladl-erank which is mounted on the bolt, so that when the dead-bolt is shot the (ail of the bell-erank is out of the we of the cam on the escutcheon E (this being the escutcheon for tho outside of the door). and hence
the latch can be operated only by the key after the bolt has been retracted. The latch-bolt may be operated by the knobs at II, and these being provided with split-hub and swivel-spin dle, the outside knob may be stopped by the stop lever L. The escutcheon C is used only for locking the dead-bolt from the inside, and the escutcheon E makes a whole revolution to unlock the dead-bolt, and a further partial revolution to retract the latch ; or, if the dead-bolt is not shot, the latter motion alone is made.
The Sargent "Easy Spring" Lock is illustrated in Fig. 3, which shows the interior mechanism. The construction is such that the bolt can be reversed so as to make the lock either " right " or "left hand " before it is applied to the door. The spring at tachment causes the door to latch gently when closed. This consists simply of a stiff spiral spring so arranged as to operate under a long leverage on the latch-bolt, and at a direct pull on the knob.
A Keyless Latch-Lock.—Fig. 4 shows a cross section of a door exposing a keyless spring latch lock, made by the Miller Lock Co., of Philadelphia, in place. The door may he unlatched from the inside by turning the knob shown in above cut, and the latch may be "thrown off" by the stayback. Light is not required in opening the latch from inside the door. From outside the door it is unlocked by turn ing the dial, as in opening an ordinary safe, but in less time, being necessary to turn once only to each of the three members of the combination.