IMPROVE- MENTS IN LOCKS
Year: 1865

page_text: PROVISIONAL SPECIFICATION left by William Hodson at the Office of
the Commissioners of Patents, with his Petition, on the 22nd May
1865. A communication from abroad by James Hutson, residing at
Janesville, in the State of Wisconsin, in the United States of America.
I, WILLIAM HODSON, of Candlesby House, Spilsby, in the County of
Lincoln, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN LOCKS," to be as follows:-
This Invention has reference more particularly to locks for doors, and
consists in so arranging a lock in combination with a sliding plate actuated by
the key, that when the door is locked from the inside such plate is slid in
front of the outside keyhole, thereby closing it, and thus preventing any
tampering with the lock from the outside, in which position the plate is held
as firmly as the bolt. Furthermore, the lock is so arranged that the door can
be locked from the outside without moving the sliding plate, whereby the
unlocking of the door from the inside is prevented. For this purpose a plate.
is arranged to slide backwards and forwards between grooves upon the
external surface of the outer plate of the lock. This sliding plate has a key-
hole which, when in its backward position, i.e., when the bolt of the lock is.
not shot, is situated over the keyhole of the outer plate so that the key can
be inserted, but when the plate is slid forward by the action of locking the
door from the inside, the body of the sliding plate covers the keyhole of the
outer plate of the lock. A stud attached to the sliding plate passes through a slot
in the outer lock plate, and is fixed inside the lock to a supplemental bolt which

page_text: is actuated by the key in the ordinary manner, and which only serves to impart
the before-described motion to the sliding plate. The lock has, furthermore,
an ordinary bolt, the shooting of which locks the door, and the motion of
which is regulated by means of a stud upon the same passing into notches in
a tumbler of the ordinary description. This tumbler has other notches
into which fits a stud on the supplemental bolt to the sliding plate, so that on
moving both this and the locking bolt by the operation of locking from the
inside both bolts are held securely in the locked position by the respective
notches of the tumbler. The beard of the key is so formed by cutting away a
portion of its lower end, that when inserted from the inside it actuates both
the locking bolt and the supplemental bolt as described, but when inserted
from the outside it only actuates the locking bolt, leaving the supplemental
bolt, and consequently the sliding plate, stationary. It will be seen that if
when the parts of the lock are in this position the key is inserted from the
inside it cannot be turned so as to unlock the door, as in endeavouring to do
so a portion of the beard will come in contact with the supplemental bolt in
its backward position, and its further motion will consequently be arrested.
Instead of having only one tumbler to the two bolts as described, a separate
tumbler may be provided to each bolt. The edges of the keyhole in the
sliding plate are bevilled off on the outside surface so as not to afford any
shoulder for a lever to have purchase against in endeavouring to force back
the plate so as to uncover the keyhole of the lock when the door is locked
from the inside.
Although I have described the sliding plate as applied to an ordinary
tumbler lock it may also be applied to locks having several tumblers, or to
locks having wards and no tumblers save the one requisite for the supple-
mental bolt.
Although I have stated that this Invention is particularly applicable to door
locks, yet it is evidently also applicable to any locks in which it is desirable to
close the keyhole when the bolt is shot or in which the locking may be
effected on both sides of the lock.