Improvements in Multiple-key Locks.
Year: 1891

page_text: Date of Application, 29th Dec., 1891
Complete Specification Left, 19th Sept., 1892-Accepted, 3rd Dec., 1892
PROVISIONAL SPECIFICATION.
Improvements in Multiple-key Locks.
A communication from HENRY ELLIOT, of Los Angeles, County of Los Angeles,
State of California, United States of America, Landlord.
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of
Middlesex, M.I.M.E., do hereby declare the nature of this invention to be as
follows:-
The object of my invention is to provide means whereby the person having
primary control of a room or other enclosure can allow a lessee or other person
to have joint access thereto while excluding others, and can, at pleasure, prevent
such other person from gaining access.
My invention comprises a lock provided with two dissimilar keys and with a
bolt having two dissimilar sets of key receiving notches whereby the second key
is adapted to engage the bolt and move it forward a distance after the first key
has moved the bolt the usual distance, thus causing the first key to be inopera-
tive until the second key is used to partially return the bolt.
The accompanying drawings illustrate my invention.
Fig. 1 shows the interior of the lock with the bolt in its withdrawn position
ready to be driven forward by the first key of the series.
Fig. 2 shows the lock with the bolt projected to its first locked position and
ready to be withdrawn by the first key of the series or to be further advanced by
the second key of the series.
Fig. 3 shows the lock with the bolt fully advanced by the second key of the
series and in position to be retracted by such second key.
Fig. 4 shows a portion of the lock in cross-section with the first key of the series
inserted and turned to engage the bolt and dog.
Fig. 5 shows a portion of the lock in cross-section, with the second key of the
series inserted and turned to engage the bolt and dog.
A is a bolt provided with a series of two key receiving notches B, C, unlike in
depth. D is the dog provided with a series of bolt-retaining lugs or catches E, F,
arranged to engage the bolt pin or lug G which normally rests in the notches a, b, c
which are arranged to receive it when the dog is at rest. H, H' are the keys.
To economize space, I chamber the bolt with the recess I to receive the end of
the dog and its spring J when the bolt is retracted.
In practice it is designed for the landlord or other principal to retain one each
of the keys H and H', while the tenant or other one having secondary rights, is
given the first key H of the series. The landlord and tenant each have control
over the lock so long as the first key only is applied in fastening the lock.
In case the tenant fails to settle his bill, or if for any other reason it should be
desired to exclude him from his room, the second key H of the series is applied to
further advance the bolt to the position shown in Fig. 3, and then the first key H
becomes useless until the second key H¹ is applied to again throw the bolt into the
position shown in Fig. 2.
L represents one wall of the case of the lock provided with the key-hole M.
Dated this 29th day of December 1891.

page_text: COMPLETE SPECIFICATION.
Improvements in Multiple-key Locks.
A communication from HENRY ELLIOT, of Los Angeles, County of Los Angeles,
State of California, United States of America, Landlord.
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
Member of the Institution of Mechanical Engineers, do hereby declare the nature
of this invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
The object of this invention is to provide means whereby the person having
primary control of a room or other enclosure can allow a lessee or other person to
have joint access thereto while excluding others, and can, at pleasure, prevent such
other person from gaining access.
A further object is to provide means whereby door lock can be made proof
against pass or skeleton keys.
The invention comprises a lock having its bolt provided with a series of dissimilar
key receiving notches so arranged with relation to the key hole, that the bolt may
be successively advanced or retracted by a series of dissimilar keys applied in
rotation in said key-hole.
The accompanying drawings illustrate this invention.
Fig. 1 shows the interior of the lock with the bolt in its withdrawn position
ready to be driven forward by the first key of the series.
Fig. 2 shows the lock with the bolt projected to its first locked position and
ready to be withdrawn by the first key of the series or to be further advanced by
the second key of the series.
Fig. 3 shows the lock with the bolt fully advanced by the second key of the
series and in position to be retracted by such second key.
Fig. 4 shows a portion of the lock in cross-section with the first key of the
series inserted and turned to engage the bolt and dog.
Fig. 5 shows a portion of the lock in cross-section, with the second key of the
series inserted and turned to engage the bolt and dog.
A is a bolt provided with a series of two key-receiving notches B, C, unlike in
depth. D is the dog provided with a series of bolt-retaining lugs or catches E, F,
arranged to engage the bolt pin or lug G which rests in the notches ს, C which
are arranged to receive it when the dog is at rest in either of its three positions.
H, H' are the keys.
a,
To economize space, the bolt is chambered with the recess I to receive the end of
the dog and its spring J when the bolt is retracted.
In practice it is designed for the landlord or other principal to retain one each
of the keys H and H', while the tenant or other one having secondary rights, is
given the first key H of the series. Thus the landlord and tenant each have control
over the lock so long as the first key only is applied in fastening the lock.
In case the tenant fails to settle his bill, or if for any other reason it should be
desired to exclude him from his room, the second key H¹ of the series is applied
to further advance the bolt to the position shown in Fig. 3, and then the first
key H becomes useless until the second key H' is applied to again throw the
bolt into the position shown in Fig. 2.
L represents one wall of the case of the lock provided with the key-hole M.
The two keys in this improved lock are complementary to each other as will be
seen by comparison of Figs. 4 and 5.. That is to say, the ends of the blades of the
two keys would fit each other if set point to point. For this reason when the lock
has been locked with the two keys it cannot be unlocked by a less number of keys
for the key necessary to move it from its third position to its second, is the direct
opposite of that necessary to move it from its second position to its first or unlocked
position.

page_text: It has been found in practice that this necessitates exact construction upon the
part of both such keys so that a superior degree of security results from this
improvement making it impossible, so far as my correspondent is aware to pick the
lock or unlock it without the proper keys, a hairs breadth of error being sufficient
to prevent the key from operating.
Having now particularly described and ascertained the nature of the said inven-
tion, as communicated to me by my foreign correspondent, and in what manner the
same is to be performed, I declare that what I claim is,
A lock provided with two dissimilar keys and with a bolt having two dissimilar
sets of key receiving notches whereby the second key is adapted to engage the bolt
and move it forward a distance after the first key has moved the bolt the usual
distance, thus causing the first key to be inoperative until the second key is used to
partially return the bolt.
10th day of September 1899
W. P. THOMPSON & BOULI,
Agents for the Applicant.