Certain Improvements in the Manufacture of Thumb Latches.
Year: 1885

page_text: Certain Improvements in the Manufacture of Thumb Latches.
I, JOHN LARGE, of New Summer Street, Birmingham, Warwickshire, Hinge,
Latch and Bolt Manufacturer, do hereby declare the nature of my invention for
31 to be as
CERTAIN IMPROVEMENTS IN THE MANUFACTURE OF THUMB LATCHES
follows:-
"
My Invention has reference to certain improvements in the manufacture of
thumb latches the chief object being to provide an improved means of attaching
the fulcrum-pin, on which the "thumb-bit" turns, to the door-plate by means of a
single piece of sheet or cast metal rivetted or otherwise attached thereto, instead of
as at present, by means of two pieces of sheet metal, for instance as in what are
known as "Norfolk" latches, or by forging the handle into a peculiar form
therefor, for instance as in what are known as "Suffolk" latches. By my
Invention the cost of manufacture is diminished and I am enabled to obtain greater
durability of the "thumb-bit" fulcrum-pin as it is held more firmly and more
completely protected from corrosion by the action of the weather.
"
I will first describe my Invention more particularly as applied to what are
known as "Suffolk" latches. According to this application of my Invention instead
of forming the handle with a slotted top part through which the "thumb-bit"
passes and to which it is pivotted by a pin passing therethrough I form the handle
proper separate from the top part and I make the top part either from sheet or
cast metal slotted for the thumb-bit" to pass through. Between the said metal
top part (which may be of any convenient shape) and the door-plate I provide a
fulcrum-pin which crosses the said slotted part and on which the "thumb-bit" is
pivotted, the door-plate or the top part or both being bulged outwardly to form a
recess therefor. The upper end of the handle passes through the metal top part
and is rivetted thereto the said metal top part being also rivetted to the door-plate.
I sometimes make the upper end of the handle to pass through the door-plate as
well as through the metal top part and to be rivetted thereto to increase the
strength of the same.
In applying my Invention to what is known as a "Norfolk" latch, instead of
attaching the "thumb-bit" fulcrum-pin to the door plate by holding it between

page_text: the same and the metal top part rivetted thereto as before described with reference
to a "Suffolk" latch I make the said sheet or cast metal top part so as to pass
around the said fulcrum pin which may be rivetted at the ends, and I rivet the
said metal top part to the door-plate either by an independent rivet or rivets or by
passing the handle therethrough and through the door-plate and rivetting it to the
same.
The metal top part for either a "Norfolk," "Suffolk" or other latch may be
attached either to the front or back of the door-plate but I prefer to attach it to
the front as it then forms no obstruction to the fixing of the latch on the door.

page_text: Certain Improvements in the Manufacture of Thumb Latches.
I, JOHN LARGE, of New Summer Street, Birmingham, Warwickshire, Hinge,
Latch and Bolt Manufacturer, 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 reference being had to the
accompanying drawing and to the letters and Figures marked thereon, that is
to say :-
My Invention has reference to certain improvements in the manufacture of
thumb latches the chief object being to provide an improved means of attaching
the fulcrum-pin, on which the "thumb-bit" turns to the door-plate by means of a
single piece of sheet or cast metal rivetted or otherwise attached thereto; instead
of as at present, by means of two pieces of sheet metal, for instance as in what are
known as "Norfolk" latches, or by forging the handle into a peculiar form
therefor, for instance as in what are known as "Suffolk" latches. By my
Invention the cost of manufacture is diminished and I am enabled to obtain
greater durability of the "thumb-bit" fulcrum-pin as it is held more firmly and
more completely protected from corrosion by the action of the weather.
On the accompanying drawing Fig. 1 represents in front elevation and Fig. 2 in
sectional elevation a "Suffolk" latch constructed according to my Invention and
Figs. 3, 4 and 5 shew parts of the same separately; Fig. 6 illustrates in front
elevation and Fig. 7 in sectional elevation a modified form of the "Suffolk " latch
illustrated by the preceeding Figures; Fig. 8 represents in front elevation and
Fig. 9 in sectional elevation part of a "Norfolk" latch constructed in accordance
with my Invention; Figs. 10 and 10* shew a part of the same separately and
Fig. 8* shews a modified form of the "Norfolk" latch illustrated by Fig. 8.
A is the door-plate of which a is the front and a¹ the back; B is the handle;
C is the thumb-bit and c the fulcrum-pin thereof.
I will first describe my Invention more particularly as applied to what are
known as "Suffolk" latches and for this purpose I will refer more particularly to
Figs. 1 to 5, both inclusive.
According to this example of my Invention instead of forming the handle B
with a slotted top part through which the "thumb-bit" C passes and to which it
is pivotted by a pin passing therethrough I form the handle proper (B) separate
from the top part D and I make the top part D either from sheet metal (see Fig. 4) or
of cast metal (see Figs. 1, 2 and 3) slotted at d for the "thumb-bit" C to pass
through. Between the said metal top part D (which may be of any convenient
shape) and the door-plate A I provide a fulcrum-pin c which crosses the said
slotted part d and on which the "thumb-bit" C is pivotted the door-plate A or the
top part D or both being bulged outwardly or provided with a groove or recess
at for the pin c. I prefer to form a recess in the top part D only as
illustrated so as to maintain the door-plate A flat at the back a¹. The upper
end b¹ of the handle B passes through the metal top part D and is rivetted thereto
the said metal top part being also rivetted to the door-plate A at d². I sometimes
make the upper end 6¹ of the handle B to pass through the door-plate A as well as

page_text: "
through the metal top part D and to be rivetted thereto to increase the strength
of the same.
When the top part D is made of cast metal (see Figs. 1, 2, 3, 6 and 7) I make
the recess a blind at each end so as to more effectually protect the ends of the
pin c from corrosion by wet.
The metal top part D and the handle B may be formed in one piece (see Figs. 6
and 7) and this is especially applicable when the handle is made of cast metal.
In applying my Invention to what is known as a "Norfolk" latch (see Figs. 8,
8*, 9 10 and 10*) instead of attaching the "thumb-bit" fulcrum-pin c to the door-
plate A by holding it between the same and the metal top part D rivetted thereto
as before described with reference to a "Suffolk" latch, I make the said sheet
metal (Fig. 10) or cast metal Fig. 10° top part D₁ so as to pass around the said
fulcrum-pin c (see Figs. 9, 10 and 10*) which may be rivetted at the ends and I rivet
the said metal top part D¹ to the door-plate A either by an independent rivet d³ or
rivets (see Figs. 8 and 9) or by passing the handle B therethrough and through
the door-plate A and rivetting it to the same (see Fig. 8*).
My Invention can be applied to "Gothic" and all other kinds of thumb-latches
similarly as herein before described with reference to a "Norfolk" or "Suffolk "
latch.
"
The metal top part D, D¹ when made separately from the handle B for either a
Norfolk," "Suffolk or other latch may be attached either to the front a or
back a¹ of the door-plate but I prefer to attach it to the front a as illustrated in
my drawing as it then forms no obstruction to the fixing of the latch on the door.
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 improvements in the manufacture of thumb-latches hereinbefore described
and illustrated by Figs. 1, 2, 3, 4, 5, 8, 8, 9 10 and 10 of the accompanying
drawing, that is to say, making the said latches with a separate cast or sheet metal
top part in the several ways described and illustrated and attaching the thumb-bit
fulcrum-pin to the door-plate by means of the said top part substantially as
described and represented.
2. The improvements in the manufacture of thumb-latches hereinbefore described
and illustrated by Figs. 6 and 7 of the accompanying drawing, that is to say,
providing a groove or recess d¹ in the top part of the handle D or in the door-
plate A or in both for the thumb-bit fulcrum-pin c and attaching the thumb-bit
fulcrum-pin to the door-plate by means of the said top part of the handle
substantially as described and represented.
1000