AN IMPROVED DOOR KNOCKER
Year: 1876

page_text: LETTERS PATENT to Richard Locke Johnson, of No. 2, Bury Place, Blooms-
bury Square, London, in the County of Middlesex, Physician, for the
Invention of "AN IMPROVED DOOR KNOCKER."
PROVISIONAL SPECIFICATION left by the said Richard Locke Johnson at
the Office of the Commissioners of Patents on the 29th June 1876.
RICHARD LOCKE JOHNSON, of No. 2, Bury Place, Bloomsbury Square, London,
in the County of Middlesex, Physician. "AN IMPROVED DOOR KNOCKER."
The object of my Invention is to provide a cheap and convenient knocker, which
striking on the inside of the door, and thereby concentrating the sound within the
house or apartment, need not be of such large dimensions as ordinary outside
knockers. A further advantage of this system of knocker being that it cannot be
readily removed or injured by mischievous persons.
I propose to construct the striker or hammer of my door knocker in the form of
a crank, either in one or more pieces; one of the crank arms, which I will term the
outside lever, passes through the door, either projecting on the outside, being flush
therewith, or even countersunk therein so as to be reached only by the finger or
thumb; the other end of the crank or inside lever forms the actual hammer,
producing the sound by striking upon the bearing or bearings of the crank or upon
the door itself.
The crank is pinned upon or otherwise set to hinge or pivot upon a bearing or
bearings fixed to the inside of the door. This knocker will be actuated by simply
pressing upon the outside lever or by pulling it up or down accordingly as it is
sunk in or projects outside the door, thereby causing the inside lever to work on
the hinge pin and strike against the bearing or the back of the door, or upon a
plate or boss fixed thereto.
If the crank is made in two pieces the two levers will be joined in the bearing
or bearings, and the outside lever will be perforated so that it may be pinned longer
or shorter to suit the thickness of the door, or this may be regulated by screwing

page_text: up the outer button knob or handle more or less closely to the outside of the
door. This knocker may work in conjunction with a bell, like certain ordinary
knockers.
I may find it desirable to counterweight the crank or to use a spring, also to add
another lever to the crank so that the knocker may strike both by the to-and-fro
or the up-and-down movement of the outside lever.
My improved knocker may be made of wrought or of cast iron, or any suitable
metal or material, and of any shape and dimensions.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Richard Locke Johnson in the Great Seal Patent Office on the
29th December 1876.
RICHARD LOCKE JOHNSON, of No. 2, Bury Place, Bloomsbury Square, London,
in the County of Middlesex, Physician. "AN IMPROVED DOOR KNOCKER."
The object of my Invention is to provide a cheap and convenient knocker, which
striking on the inside of the door, and thereby concentrating the sound within the
house or building, need not be of such large dimensions as the ordinary external
knockers, a further advantage of my Invention being that it entirely precludes all
danger of the knocker being either removed or injured by mischievous persons.
And in order that my said Invention may be better understood and practically,
carried into operation I will now, with the aid of the accompanying Drawings
(whereon similar letters of reference indicate corresponding parts) proceed more
particularly to describe the same. I construct the striker or hammer (a) of my
improved door knocker in the form of a crank, which crank I prefer to form in
one piece, but if desired it may be formed either in one or more pieces. One of
the crank arms b', which I will term the outside lever, passes through the thickness
of the door, and being either provided with a suitable handle at its outer extremity
projecting slightly beyond the exterior of the door, as shewn at c, Figure 1, or
having a small projecting knob or stud which may either be countersunk the same
as a bell handle, and so be flush with the external surface of the door, or may be
made to lie flush therewith without being so countersunk, and so as to allow of its
being reached and compressed by the finger or thumb only, or it may form a slight
projection beyond the surface of the door, as shewn at c', Figure 2. The upper
end of the crank or inside lever b forms the actual hammer a, which produces the
sound by striking upon the bearing or bearings of the crank or upon a suitable
boss or projection formed thereon, or upon the back of the door itself.
The crank is pinned or otherwise set to hinge or pivot upon a second bearing or
bracket or bearings or brackets (e) fixed to the inside of the door by screws, or in
any other convenient manner. The knocker is actuated by simply pressing upon
the external end c of the crank arm 61 of the lever b, or such crank arm may be
made to move either up or down longitudinally, laterally, or obliquely, as may be
desired, according to the direction of the slot which is made in the shield plate h
and also accordingly as the handle or knob or other projection is arranged on the
outside of the door, thereby causing the inside lever 6 to work on the hinge pin e¹
and strike against the bearing fixed to the back of the door or on the back of the
door itself or upon a plate or boss affixed thereto, as before described.
If the crank be made in two pieces I prefer that they should be joined in the
bracket or bearing or brackets or bearings e. I also prefer that the inner end of
the lever or crank arm b¹ be perforated, as shewn in the Drawing at f, so that it
may be pinned longer or shorter to suit the thickness of the door; or this may be
regulated by screwing up the outer button, knob, or handle c more or less closely to

page_text: the outside of the door. My improved knocker may also, if desired, be made to.
work in conjunction with a bell in the same manner as many ordinary knockers:
and bells.
I sometimes find it desirable to counterweight the crank, and in this case I
prefer to fix a suitable collar or neck on the lever arm or spindle b¹ to prevent the
stud or knob projecting too far beyond the external surface of the door. Some-
times I prefer to use a spring or too add another lever to the crank so that the
knocker may strike both by the to-and-fro or the up-and-down movement, or by
the compression of the outside lever.
My improved knocker may be made of wrought, or of cast iron or brass, or of
any other suitable metal or material and of any shane and dimensions
DESCRIPTION OF THE DRAWINGS.
Figure 1 of the accompanying Drawings is a side view of my improved arrange-
ment of knocker, furnished on the outside with a handle or knob c, which is made
to move up and down, or laterally or obliquely, or to be compressed as already
described. a is the hammer; b, the lever actuating such hammer; 6¹, the crank
arm or spindle, with the perforations f formed at its inner end to allow of the
length thereof being adapted to the thickness of the door; e, the bracket or
support, and e¹, the pivot joint whereon the lever b works when actuated by the
crank arm b¹. In this arrangement I prefer to make the fore part of the head or
hammer of the knocker larger and heavier than the rear so as to ensure its effective
action, as shown in the Drawing.
Figure 2 shews a side view of the alternative arrangement herein-before
described of a stud or knob c to be compressed or moved up or down, or laterally,
or otherwise. When this arrangement is adopted I prefer to make the back of the
head or hammer of the knocker rather larger and heavier than the fore part so as
to ensure its effective action, as shewn in the Drawing. The nut or collar on the
spindle or lever arm b¹ is indicated at c³ in this Figure.
Figure 3 is a plan view, and shews the metal base plate or bearing g which is
screwed or otherwise fastened to the inside of the door.
Figures 4, 5, 6, 7, are four views of the shield plate h which is affixed to the
exterior of the door to prevent its being worn by the action of the knob or other
projection formed on or attached to the external end of the crank arm b¹, and
shew such plate formed either with a longitudinal, lateral, or oblique slot therein,
or an annular or any other conveniently shaped orifice to allow of the necessary
play of the knob, handle, or other projection. The shield plate h may be of any
other shape than that shewn in the Drawings if desired.
Having now particularly described and ascertained the nature of my said
Invention, and the manner of carrying the same into effect, I would have it
understood that I do not wish to confine myself to the precise details of con-
struction herein-before set forth, as the same may be modified without departing
from the principle of my Invention by springs, hinges, or other suitable means, but
what I claim and desire to secure by the herein-before in part recited Letters
Patent is,
1. The fixing a knocker internally instead of externally, as hitherto, for the
purpose of giving a louder and clearer alarum to the inmates, and also for the
purpose of preventing any wilful injury thereto by any mischievous person or
persons.
2. The arrangement of the hammer head, lever, and crank handle, with the
metal or other bearings and brackets or supports, substantially as herein-before
described and illustrated.
3. The moving the handle of the knocker either longitudinally, laterally, or
obliquely, or compressing the same, substantially as herein-before described.
In conclusion I would add that my improved knocker inay be made either plain

page_text: or ornamental, and that it is both inexpensive and also far more elegant in
appearance than those now in general use.
In witness whereof, I, the said Richard Locke Johnson, have hereunto set my
hand and seal this Twenty-eighth day of December in the year of our
Lord One thousand eight hundred and seventy-six.
RICHARD LOCKE JOHNSON. (L.S.)