Improvements in and in Connection with Door Letter-box Indicators.
Year: 1887

page_text: [Communicated from abroad by ALBERT FRANK HOCHSTADTER, of the City and State
of New York, United States of America, Merchant.]
Improvements in and in Connection with Door Letter-box Indicators.
I, HERBERT JOHN ALLISON, of 52 Chancery Lane, London, in the county of
Middlesex, Patent Agent, 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:-
My invention has for its object the construction of a suitable indicator which will,
whenever a letter is dropped into the mail box, show that there is mail in the box, for
the person in whose office or room the indicator is placed. This invention is intended
more particularly for use in office buildings, apartment houses and residences which
have a letter box into which the postman drops the mail for the person whose box it is.
In the drawings Figure 1, is a front view of the indicator case, which in this figure
is shown as also containing a clock. The slide of the case is represented as being
drawn nearly out, so as to expose the interior connections to view.
Figure 2 is a detached view taken at right angles to Figure 1, and shows the mail
indicator lever and connections on an enlarged scale.
Figure 3, represents the letter box when open, and shows the metallic inclines LL,
which form a chute for the letters when the door of the box is closed. In this figure
the mail rack which makes the electric circuit appears in front view.
Figures 4 and 5, are respectively an end view and a plan of the letter rack, the
front view of which is shown in Figure 3, such end and plan views being on an
enlarged scale.
In these drawings, similar reference letters indicate corresponding parts.

page_text: A represents a thin metallic cross piece within the indicator case. B is a lever arm
carrying a gong hammer, and B' represents a gong. C represents lugs or brackets
to which the cross bar A is pivoted. These brackets are secured by screws to a
base E¹. D represents the pivot screws by which the cross bar A is pivoted to the
brackets C. Fis the mail indicator lever which extends from the side of the cross
bar A. G is the metallic support to which an electro-magnet G¹ is secured at one
end, and at the other end this support G has an adjustment or limit serew F', which
limits the downward motion of the lever F. HH represent binding posts holding
wires from which the electric current is conveyed to the indicator. I represents a
slide having an opening K, which exposes the indicator to view when there is any
mail in the box.
case.
In Figure 3, the rack shown in the lower part of the mail box is constructed of a
balance rod g, the ends of which are pivoted by the screws f to brackets h, which are
screwed to the bottom of the box; this rod has extension arms d, d, and is balanced
by a weight e. The outer ends of the extension arms are bent as shown in figure 4,
and upon these ends a small platinum wire c is secured. These platinum wires
connect when the circuit is closed with the platinum contact piece b, shown in
figures 4 and 5 as being secured to the cross piece j. The platinum contact pieces b
connect with the wires secured by the binding posts H'H', one of which is connected
with a battery shown in Figure 3, and with one of the binding posts of the indicator
When the door of the letter box is closed, the metallic inclines L, L, one of
which is secured inside to the back wall thereof, and the other to the inside of the
door, together form a chute for the mail when it is put through the opening in the
letter box. The mail as it is put in, is directed by this chute to the rack M, and as it
strikes the rack, the weight thereof will be sufficient to overcome the weight e which
counterbalances the extension arms of the rod g, and the effect will be to tip the
extension arms down far enough to cause the platinum wires c, on the ends of these
arms d, to come in contact with the pieces b, and thus the circuit will be closed and
the electrical current will pass to the indicator and raise the lever F, while at the
same time the gong will ring. The mail indicator will then remain stationary until
the letters or other mail is removed from the letter box, and during all the time that
the letter box contains any mail, the indicator will be exposed to view through the
opening K, of the slide I. When the mail is removed from the letter box, the indicator
lever F will be dropped again and disappear from sight.
I have shown the indicator case as being made to enclose a clock, because if one be
absent from his office or room when the mail is dropped into the letter box, he will
not hear the ringing of the gong, but would be likely to look at the clock to see the
time of day upon his return and his attention would be at once directed to the fact,
that there was some mail for him. This form of indicator however is not absolutely
essential to my invention as I may vary it by dispensing with the clock entirely, or it
may be constructed in a different form, as, for instance, instead of having the lever
behind the slide, as shown, an opening could be made in the lower part of the case
and a button or other device passed out of the opening by the electrical current when
the mail was deposited in the box.
In practice I locate the indicator in the room most used by the party for whom it is
constructed, and the letter box may be placed in the hall of an office building, or at
the side of the door or other convenient place of an apartment or dwelling house.
The advantages derived from the use of a mail indicator, which by the gravity of
the mail, will show that the postman has been around, are considerable, because it
often happens that the postman has to ring the bell, and wait for some one to open
the door, if no regular letter box is used; and when letter boxes are used, it also often
happens that through forgetfulness or negligence the mail remains in the box for a
considerable time after its delivery. But in the use of an electrical indicator, the
postman does not need to wait, nor does the mail remain longer than is necessary, and
if the party be in his room or office, he is instantly warned of the delivery of the mail,
and hence the conveniences of such a contrivance are apparent.

page_text: 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 :--
In combination with an indicator, a letter box having secured therein posts h, h,
rod g, pivotally connected with said posts, weight e, secured to said rod, one or more
arms & extending from said rod and being provided at the outer end thereof, with
contact piece or pieces c, said letter box being also provided with contact piece or
pieces b, corresponding to those on the arms d and electrical connections to operate
the indicator when said pieces c and are brought into contact with each other,
substantially as described.
ALLISON BROS.,
Agents for the Applicant.