IMPROVEMENTS IN DOOR, LOCK OR LATCH CHECKS
Year: 1882

page_text: cr
"
LETTERS PATENT to Walter Alfred Barlow of 6 St Pauls Churchyard in
the city of London Patent Agent and Engineer for an Invention of
IMPROVEMENTS IN DOOR, LOCK OR LATCH CHECKS Communicated to
him from abroad by Friedrich Wilhelm Boldt and Peter Christian Anton
Vogel trading under the firm of Boldt & Vogel of Hamburg in the German
Empire
PROVISIONAL SPECIFICATION left by the said Walter Alfred Barlow at
the Office of the Commissioners of Patents on the 4th October 1882.
"
WALTER ALFRED BARLOW of 6 St. Pauls Churchyard in the City of London
Patent Agent and Engineer "IMPROVEMENTS IN DOOR LOCK OR LATCH CHECKS.'
A communication from [abroad by] Friedrich Wilhelm Boldt and Peter Christian
Anton Vogel trading under the firm of "Boldt & Vogel" of Hamberg [sic] in the
German Empire
This invention relates to certain improvements, in door checks and consists in
the combination with a locking plate, of a hinged check bar, a pear shaped slot in
said Check bar; an incline formed on one edge of the check bar and a latch with a
spring bolt having a conical or beviled head so that when the door is closed the
bolt engages automatically with the check bar.
•
It is a well known fact that door checks would be used much more extensively
than they are at present if in addition to their great advantages of forming a
protection against thieves, beggars, and of allowing communication with persons
outside without giving them admission into the house such door checks were free
from the disadvantage or inconvenience viz.--that if a person opens the door in
going out the door check must necessarily be disengaged and in most cases a second
person is required to throw the door check again into action, or the person having
opened the door must perform this operation by means of a key or otherwise, and
if this operation is forgotten the door check is useless.
In order to overcome this disadvantage we have constructed a door check which
is automatically thrown in a position to operate by the act of closing the door.
The apparatus is constructed as follows:-
The locking plate is provided with a hinged check bar within which is a pear

page_text: shaped slot and from its edge projects an incline. When the check bar is free to
follow its inherent gravity it drops into a slot formed for its reception in the locking
plato.
The latch is provided with a bolt which is subjected to the action of a spring
having a tendency to throw the bolt outwards. Said bolt can be moved back
against the action of the spring by a button on the inside or by a key from the
inside of the door. The head of the bolt is conical or bevilled and when the door
is closed it rides up on the incline of the check bar and after having passed this
incline it passes through the largo end of the pear shaped slot.
If the door is now opened without throwing. back the bolt said bolt throws the
check bar up into an inclined position and as the body of the bolt slides out into
the narrow part of the slot, the lead catches behind the edges of said slot and
the door can only be opened as far as the check bar will permit.
If a person desires to go out of the door the bolt is pressed back by means of
the button and when the door is closed the head of the bolt engages again
automatically with the slot of the check bar.
In the same manner a person provided with a proper key can throw the bolt
back from the outside and after entering and closing the door the door check is
automatically thrown into operation.
If the latch is by a lever or other convenient mechanical arrangement connected
to the spring bolt of the lock of the door, the door can by means of the .check
button and Check key at same time be locked and opened.
From the foregoing description it will be seen that this improved door check is
always in proper position for operation and at the same time persons provided with
a proper key can enter without the aid of a second person.
1

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Walter Alfred Barlow in the Great Seal Patent Office on the
4th April 1883..
WALTER, ALFRED BARLOW of. 6 St. Pauls Churchyard in the City of London
Patent Agent and Engineer "IMPROVEMENTS IN DOOR, LOCK, OR LATCH CHECKS;":
a communication, to me from abroad by Friedrich Wilhelm Boldt, and Peter
Christian Anton Vogel trading under the firm of Boldt and Vogel of Hamburg in:
the German Empire.
:
.:
This Invention relates to certain improvements in door checks and consists in
the combination with a locking plate, of a hinged check-bar; a pear shaped slot in
said check bar, an incline formed on one edge of the check bar and a latch with a
spring bolt having a conical or beveled head, so that when the door is closed the
bolt engages automatically with the check bar.
It is a well known fact that door-checks would be used. much more extensively
than they are at present; if, in addition to their great advantages of, forming a
protection against thieves, beggars unauthorized persons and so forth and of
allowing communication with persons outside without giving them admission into
the house such door checks were free from the disadvantage or inconvenience viz,
that if a person opens the door in going out, the door check must necessarily be
disengaged and in most cases a second person is required to throw the door check,
again into action; or the person having opened the door must perform this operation
by means of a key or otherwise and if this operation is forgotten the door check is
useless.
In order to overcome this disadvantage there has been constructed a door check
which is automatically thrown in position to operate by the act of closing
the door.
The invention is illustrated in the accompanying drawings wherein :-
Fig. 1 represents an inside view of portion of a door provided with this improved
door check; Fig. 2 is a horizontal section of the same through line x, x Fig. 1 ;
Fig. 3 is a face view of the lock plate showing the pivoted or hinged check bar.
partly raised; Fig. 4 is a horizontal section through line y, y, Fig. 3; Fig. 5 is an
inside view of the latch; Fig. 6 is a transverse vertical section of the same; Fig. 7
is a like view to that shown in Fig. 1 illustrating means for locking the door by
giving further throw to the bolt; Fig. 8 is a like view of this modification to Fig. 3
but without the check bar raised; Fig. 9 is a horizontal view of Fig. 7 partly in
section.
Similar letters indicate corresponding parts.
The apparatus is constructed as follows:-
The locking plate A is provided with a hinged check bar B within which is a
pear shaped slot a and from its edge projects an incline b. When the check bar is
free to follow its inherent gravity it drops into a slot formed for its reception in
the locking plate as shown in Figs. 1 and 2 and 7 and 9.
The latch C is provided with a bolt D which is subjected to the action of a
spring c having a tendency to throw the bolt outwards as shown in Figs. 1, 2 and 5.
Said bolt can be moved back against the action of the spring by a button d on the
inside or by a key K from the inside of the door. The head e of the bolt is conical
or bevilled and when the door is closed it rides up on the incline b of the check
bar B and after having passed this incline it passes through the large end of the
pear shaped slot a.

page_text: If the door is now opened without throwing back the bolt D said bolt throws
the check bar up into an inclined position as shown in Fig. 3 and as the body of
the bolt slides out into the narrow part of the slot a the head e catches behind the
edges of said slot and the door can only be opened as far as the check-bar will
permit.
If a person desires to go out of the door, the bolt D is pressed back by means of
the button & and when the door is closed the head of the bolt engages again
automatically with the slot a of the check bar
In the same manner a person provided with a proper key K can throw the bolt D
back from the outside and after entering and closing the door the door check is
automatically thrown into operation.
When the latch is by a lever or other convenient mechanical arrangement con-
nected to the spring bolt of the lock of the door, the door can by means of the
check button and check key at same time be locked and opened.
According to a modification as shown in Figs. 7, 8 and 9 the bolt D has greater
play towards the door post so that if pushed further towards the door post it will
catch the behind the locking plate A and positively bolt or lock the door. In
the said Figs. 7, 8 and 9 the bolt is shown engaging with the check bar B only.
From the foregoing description it will be seen that this improved door check is
always in proper position for operation and at the same time persons provided with
a proper key can enter without the aid of a second person.
Having now described the nature and particulars of the said Invention I
claim:-
In door, lock or latch checks, the combination of the locking plate A, the check
bar B, hinged therein, the pearshaped slot a in said check bar and the spring
bolt D of the lock, said bolt D having a conical or bevilled lead e and whether
said bolt D be operated by key, handle or push button, the whole constructed and
operating as herein set forth and shown by the drawings.
In witness whereof I the said Walter Alfred Barlow have hereunto set iny
hand and seal this twenty ninth day of March in the year of our Lord one
thousand eight hundred and eighty three