Improved Door Lock.
Year: 1897

page_text: Date of Application, 18th May, 1897-Accepted, 28th Aug., 1897
COMPLETE SPECIFICATION.
Improved Door Lock.
I, WILLIAM HENRY HOFFMANN, Merchant of No. 270 West Broadway in the
City of New York, in the County of New York and State of New York, in the
United States of America, 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:-
This invention relates to a new and improved door lock, which is so constructed
that it can readily be locked or unlocked from the outside or inside and is provided
with a series of bolts, the entire device being simple in construction, strong and
lurable.
The bolts are mounted to slide on a door and are engaged by a cam piece adapted
to be turned by means of a knob and locked in place by a tumbler, which can be
disengaged therefrom by means of a suitable key, all as will be fully described and
set forth hereinafter.
In the accompanying drawings forming a part of this specification and in which
like letters of reference indicate like parts in all the figures
Figure 1 is an elevation of part of a door provided with my improved lock.
Figure 2 is an elevation of the lock mechanism, the outer cover plate being
removed.
Figure 3 is an inner face view of said cover plate.
Figure 4 is a view similar to Figure 2 showing the parts in another position.
Figure 5 is a vertical transverse sectional view on the line 5 5 of Figure 4.
The lock casing A is to be mortised into a door m in the usual way or secured on
the inner face and in the top, bottom and outer edge wall of the casing, the three
bolts B1 B2 B3 are guided, the bolt B' extending to the swinging edge, the bolt B³
to the top edge and the bolt B3 to the bottom edge of the door, the bolts being
suitably guided on the door to slide lengthwise.
Each bolt is provided at its inner end with a notch or transverse groove a for
receiving the cam ridge C formed on a cam piece I located within the casing A
provided with a hub d and secured on a knob spindle E mounted to turn in the
casing and extending transversely through the door and casing and projecting
from both faces of the door.
Tumblers F are pivoted at F1 to the inner surface of the cover plate A¹ and their
free ends are provided each with a nose F which are pressed downward by a
spring G to engage said noses with a lug D¹ on the cam piece D and lock the same
A flat lever H is
in vertical position with the several bolts thrown out or shot.
pivoted at H¹ to the inner side of the cover plate A¹ and is provided at its lower end
with a handle knob H2 which passes through a curved slot I in the cover plate and
at its upper end sail lever H has a lateral flange J which can act on the rounded
shoulders K on the bottom edges of the tumblers F and rest against the adjacent
straight shoulders L on the tumblers.
A key can be passed through the key hole M in the casing and the prongs on its
bit can pass through the slots N in a key guard plate to prevent the use of

page_text: improper keys, the ends of the bit prongs acting on the upper edges of the tumblers
to raise the ends having the noses F2.
The spring P acting on the lug D2 of the cam piece D tends to throw the same
into vertical position.
The operation is as follows:
Figure 2 shows the bolts shot and the same locked in place so that it is impossible
to open the door by turning the knob, the cam piece D being locked in place by
the tumblers F.
To unlock the door from the outside the proper key is inserted through the
key hole M and turned to cause its bit to disengage the tumblers F from the
lug D whereupon the cam piece I can be turned by means of the knob spindle E
to withdraw the bolts as shown in Fig. 4.
Before releasing the knob spindle and while the cam piece D is in the position
shown in Figure 4 the lever H is shifted to rest against the shoulder L as shown
in Figure 4 and thereby hold the tumblers in raised position to prevent their
engaging the lug D¹ on the cam piece D when the latter, after the releasing of the
knob spindle is thrown by its spring P into the vertical position.
The door can now be opened and closed by means of the knob spindle in the
usual manner.
If the door is to be locked from the inside the lever H is shifted to release the
tumblers which then engage the lug D¹ on the cam piece D as soon as the latter
assumes the vertical position. To lock the door from the outside it is only
necessary to turn the knob spindle from the inside, to withdraw the bolts, then
open the door, adjust the lever H so as to release the tumblers and then close the
door from the outside whereupon the tumblers will at once engage and lock the
cam piece D and thereby the bolts.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
1. The combination with a lock casing, of a series of bolts guided to move in
the direction of their length only and each composed of a single continuous piece,
a rotative cam piece mounted to turn in said casing, and engaging the inner end
of each bolt, a tumbler in the casing for engaging and locking the cam piece, a
lever for shifting the tumbler and means for turning the cam piece, substantially
as herein shown and described.
2. The combination with a lock casing, of a series of bolts guided to move in
the direction of their length only and each composed of a single continuous piece;
a cam piece mounted to turn in the casing and engaging the inner end of each
bolt, a tumbler in the casing for engaging the cam piece, a lever for shifting the
tumbler, a key guard below a key hole in the casing and means for turning the
cam piece, substantially as herein shown and described.
TONGUE & BIRKBECK,
Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicant.