IMPROVEMENTS IN INDICATOR LOCKS
Year: 1881

page_text: LETTERS PATENT to Alexander Melville Clark, of 58, Chancery Lane, in the
County of Middlesex, Patent Agent, for an Invention of "IMPROVEMENTS
IN INDICATOR LOCKS." A communication from abroad by the Eagle Lock
Company (Incorporated), of Terryville, Litchfield County, State of Connecticut,
United States of America.
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark
at the Office of the Commissioners of Patents on the 24th March 1881.
ALEXANDER MELVILLE CLARK, of 58, Chancery Lane, in the County of
Middlesex, Patent Agent. "IMPROVEMENTS IN INDICATOR LOCKS." [A com-
munication from abroad by the Eagle Lock Company (Incorporated), of Terryville,
Litchfield County, State of Connecticut, United States of America.]
This Invention relates to certain improvements in indicator pad-locks in which
a change is made in the indicator wheel and a different set of symbols, figures, or
letters made to show through openings in the case for the purpose of enabling the
proper authorities to detect any surreptitious opening of the lock. The Invention
has reference more particularly to that type of lock in which an annular indicator
turns loosely in a peripheral seat in the lock case, and the improvements consist,
first, in the peculiar construction of the annular indicator wheel; secondly, in its
combination with the bolt mechanism; thirdly, in the peculiar construction of the
bolt mechanism; fourthly, in the peculiar construction of the case; and, fifthly,
in a modified structure of case when made of sheet metal, as hereafter
described.
The lock case is formed of three parts, the middle portion of which is cast and
has a web or partition and a peripheral rim or flange and the other parts of which
are simple face plates. The partition of the middle piece is not midway of the
rim, but a little nearer the one face plate than the other, so that it forms with the
latter face plate a deep compartment for the bolt mechanism and with the former
face plate a shallower compartment for the indicator mechanism. In attaching
D

page_text: these face plates permanently to the central piece the peripheral rim of the latter
is formed with shoulders, which project through slots in the edge of the plates and
are rivetted down to tightly hold the same. Upon the partition of the middle
section is formed the key pin adapted to receive the key which is formed with two
diametrical bits. The shackle bar is pivoted at one end and provided with one or
more notches at its other end for engagement with the locking bar. This locking
bar has a tooth or lug, which engages with the notch of the shackle bar and
upon its rear side another lug for engagement with the tumbler. The tumbler is
pivoted upon a centre pin, and is normally held down by a spring, and is provided
with a notch, which when the tumbler is raised receives the lug on the back of the
locking bar and allows the latter to be withdrawn from the shackle. This tumbler
is slotted and guided in its movement by a pin. The locking bar is pivoted on a
pin, and has its lower end bent around and under the key pin, while the tumbler
rests above it, so that immediately after one bit of the key acts upon the tumbler
to raise it the other bit acts upon the locking bar to withdraw it from the shackle,
the locking bar being forced into engagement with the shackle by a spring. On
the opposite side of the shackle bar to, the locking bar I place a seat or abutment
pivoted upon a pin. To the lower end of this seat or abutment I joint the upper
end of a curved lever fulcrumed upon the pin which forms the centre of the
locking bar. This abutment has a lug, which when the locking bar is engaged
with the shackle, rests in a recess of said locking bar, and which lug, when the
locking bar is drawn back, rests against a shoulder of the locking bar and holds it
back. Now the point of contact of the end of the shackle bar with the abutment
I arrange to be inside of the fulcrum pin of the abutment, so that when the shackle
bar is closed its end strikes the abutment and turns it, causing its lug to pass off
the shoulder of the locking bar into the recess, at which time the locking bar is
forced by its spring into engagement with the shackle.
The function of the curved lever is as follows:-When the locking bar is being
withdrawn from the shackle the same bit of the key which acts upon the locking
bar also acts upon the lower end of the curved lever, throwing it outward and its
upper end inward, which movement tilts the abutment outward and raises its lug
to a position where it rests against the shoulder of the locking bar.
. So far I have only described the construction and operation of the locking
mechanism. I will now proceed to describe the construction of the indicator
mechanism and its cooperation with the locking mechanism. The main indicator
wheel is of annular form and turns loosely in a seat at the opposite side of the
partition to the bolt mechanism. This ring or wheel has a ring of teeth upon its
flat side next the partition, which are received in a recess on said partition and has
upon its outer face a ring of crown teeth projecting at right angles from the
periphery of the ring, while a recess in its outer face is filled with celluloid or other
equivalent material to give a good background for the figures or letters that are
placed thereon. Meshing with the crown teeth of this wheel are three subsidiary
indicator wheels, which are carried by pins that are attached to the face plate on
the back side of the lock. Each one of these wheels is provided with a ring of
figures or letters, which show through openings in the case and the teeth of which
wheels and the numbers or letters thereon are arranged for a differential effect to
prevent the easy recurrence of the same symbols. Where the indications on the
ring or annular wheel show through the case this face plate is depressed to bring
the case down to the plane of this wheel. Now to connect these wheels with the
bolt mechanism the middle plate or partition of the case is cut away just opposite
the teeth on the back of the annular dial and a pawl is jointed to the upper end of
the locking bar and protrudes through the opening in the middle partition and acts
upon the teeth of the indicator wheel to move it and change the indications every
time the locking bar is withdrawn. I may, however, not use an articulated or
jointed pawl, but may have a rigid stud or spur formed on the side of the locking
bar, which spur acts upon the teeth of the annular indicator to move it. In such
case, however, the locking bar must be connected with its fulcrum pin loosely, so as

page_text: to permit the slight lateral variation necessary to allow the spur to pass over the
teeth of the indicator and the locking bar and spur will be forced against the teeth
of the indicator ring by a flat spring on the face plate.
than
To lock the indicator ring so as to prevent its being moved by other agency
the locking bar I employ an elbow lever fulcrumed upon the same pin with the
tumbler, and the arms of which lever are pressed upwardly by the tension of a
spring. The upper one of the arms of this elbow lever has its end bent and
extended through an opening in the middle partition, where it engages with the
teeth of the indicator ring, while its lower end rests beneath the key pin in position
to be struck by the key bit.
Now, in opening the lock the lower bit of the key first depresses the lower arm of
the elbow lever and removes its upper arm from the teeth of the main indicator
wheel. Immediately following this the opposite bit of the key raises the tumbler
until its notch is opposite the lug of the locking bar, when the other bit of the key
strikes the lower end of the locking bar and withdraws it from the shackle, at
same time moving the indicator wheels through the agency of the pawl above.
I will now proceed to describe a sheet metal lock case forming part of this
Invention. This part of the Invention relates to a novel construction of lock
case designed to meet the requirements of that type of indicator pad lock already
described in which the bolt mechanism and indicator mechanism are arranged in
different planes with a supporting plate between the same. The object sought is
to combine an economy in the manufacture of the case with intrinsic merit in its
structure, the principle points aimed at being the largest amount of room for the
indicator mechanism in the smallest compass of case, and such a structure of a
three part case as will avoid strain on the rivets. These ends are attained by this
improved case which I will now proceed to describe in detail.
The case is constructed of three parts of substantially the same diameter and
connected by peripheral joints. The back plate is made cup shape with a consider-
able rim or peripheral portion. The intermediate supporting plate for the indicator
mechanism is more or less cut out and is also made with a peripheral rim
corresponding in diameter to the rim of the back plate, while the front plate is a
plain flat disc. All these parts are in practice made of sheet steel, and the back
and intermediate parts which have rims are struck up cold. The object in thus
striking up these parts from sheet metal is to ensure a uniform thickness of metal
and to facilitate the finishing of the case. These parts of the case are all of the
same diameter, and the two parts which are made cup shaped have the bottom
edge of one cup shaped piece fitting against the rim of the other cup shaped piece.
Although the three parts of the lock case are all cut from the same thickness of
metal the central portions of the middle plate are afterwards reduced in thickness
except at the edges where the full strength of the metal is required for the rivets.
Between the rear and intermediate parts the bolt mechanism is to be arranged,
while between the intermediate and front parts is contained the indicator mechanism
which is carried by the intermediate plate, and the figures on the dials of which
mechanism show through suitable holes in the front face plate, which holes are
located (as is also the key hole) at such points as the peculiar mechanism of the
lock may necessitate or render desirable.
To fasten the three parts of the case together I resort to a peculiar construction
and mode of operation. If the three parts of the case are connected by a set of
rivets of the same length, all passing through all three parts, much valuable space
in the indicator compartment is sacrificed and the movement of the parts therein
interfered with, and besides the case is weak, for diagonal blows on the lock case
are liable to make the parts grind on each other and strain the rivets. I employ
but one rivet which passes through the whole lock, and this fastens the front and
back parts together, then I attach to the back side of the back part three short
rivets that fasten the intermediate and back parts together, and then to the top
side of the intermediate part I attach another short rivet that fastens the
intermediate and front parts together.

page_text: Now in rivetting up these parts I first attach the front and intermediate parts
by swedging the rivet, which can be done without strain to the parts, since both
ends of the rivet are accessible, so that one end may have a rest while the other
end is being hammered. Then I fasten these two parts to the back part by
successively rivetting the one long and three short rivets. Of these rivets the long
one has both ends accessible so that it may have a rest on one side while it is
being hammered on the other, but the three short rivets rely for their resistance to
the rivetting strain upon the middle plate. To prevent springing this plate, which
might render the indicator mechanism inoperative, these rivets are placed close to
the periphery, where they have the strength of the rim to sustain the strain, and
they are made with broad shoulders, and besides a greater thickness of metal is
left in the plate just adjacent to the rim, so that the combined influence of location,
strength of metal, and size of shoulder, permit this rivetting to be successfully
accomplished without involving any springing of the parts or other objectionable
incidents.
To prevent the parts of the case from moving over each other when struck by
an obliquely delivered blow I rebate the adjacent edges of each of the parts at the
peripheral joints, so that each part fits into the next to make, when the parts are
rivetted, a firm and rigid whole. For receiving the shackle bar I construct a
peculiar pocket rivet or fulcrum joint as follows:--The rear part is formed with an
opening in its rim and is provided with an ear. I then form separately a piece
having an ear with a fulcrum pin which is milled to form a shoulder and whose
end passes through a perforation in the first ear. With the separate ear is formed
a curved right angular segment which, when the ears are fitted together, closes all
communication between the inside of the lock and the fulcrum seat. This segment
has two lugs which are designed to pass through two slots in the rear part and be
rivetted. These lugs are however not absolutely necessary, for the sides of the
segment bear against the rim of the rear part and prevent it from being pulled out,
while shoulders prevent the piece from being pushed in or moved side ways
whenever the intermediate part is rivetted down in place, the said part having a
hole which fits over the separate ear and co-operates with it to hold it as just
described.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alexander Melville Clark in the Great Seal Patent Office on the
23rd September 1881.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of
Middlesex, Patent Agent. "IMPROVEMENTS IN INDICATOR LOCKS." A com-
munication from abroad by the Eagle Lock Company (Incorporated), of Terryville,
Litchfield County, State of Connecticut, United States of America.
This Invention relates to certain improvements in indicator padlocks in which a
change is made in the indicator wheel, and a different set of symbols, figures, or
letters made to show through openings in the case for the purpose of enabling the
proper authorities to detect any surreptitious opening of the lock. The Invention
has reference more particularly to that type of lock in which an annular indicator
turns loosely in a peripheral seat in the lock case, and the improvements consist,
first, in the peculiar construction of the annular indicator wheel; secondly, in its
combination with the bolt mechanism; thirdly, in the peculiar construction of the
bolt mechanism; fourthly, in the peculiar construction of the case; and fifthly,
in a modified structure of case when made of sheet metal, as hereinafter fully
described.
In order that the Invention may be more readily understood I have illustrated
it in the accompanying Drawings, and will proceed to describe it in reference
thereto.
Figure 1 is a view of the locking mechanism for the shackle bar with the front
plate removed, the shackle being shown in its locked position; Figure 2 is the
same view showing the unlocked position; Figure 3 is a vertical section through
line x, x, of Figure 1; Figures 4, 5, 6, are respectively a front, back, and sectional
view of the indicator ring, the filling or enamel which carries the letters being
left out; Figure 7 is a sectional view of the middle portion of the case; Figure 8
is an inside view of the rear face plate, to which a portion of the indicator wheels
are attached, and through which the letters show.
In the Drawing A, A1, A2, represent the case of the lock formed of three parts,
the middle portion A¹ of which is cast and has a web or partition and a peripheral
rim or flange, and the other parts A, A², of which are simple face plates. The
web portion of the middle piece is not midway of the rim, but a little to one side,
so that it forms in connection with the face plate A a deep compartment for the
bolt mechanism, and with the face plate A² a shallower compartment for the
indicator mechanism. In attaching these face plates permanently to the central piece
the peripheral rim of the latter is formed with shoulders a which project through slots
in the edge of the plates, and are rivetted down to tightly hold the same. Upon
the web portion of the middle section is formed the key pin b, Figure 3, adapted
to receive the key which is formed with two diametrical bits. B is the shackle
bar pivoted upon a pin at one end; and provided with one or more notches at its
other end for engagement with the locking bar C. This locking bar has. a tooth or
lug c which engages with the notch of the shackle bar, and upon its back side a
lug d for engagement with the tumbler. D is the tumbler pivoted upon a centre
pin e. This tumbler is normally held down by a spring f, and provided with a
notch g, which notch when the tumbler is raised receives the lug & on the back of
the locking bar, and allows the latter to be withdrawn from the shackle. This
tumbler is slotted and guided in its movement by pin h. The locking bar C is
pivoted upon a pin i, and has its lower end bent around and under the key pin,
while the tumbler rests above it, so that immediately after one bit of the key acts
upon the tumbler to raise it the other bit acts upon the locking bar to withdraw it

page_text: from the shackle. The locking bar C is forced into engagement with the shackle
bar by spring j. On the opposite side of the shackle bar to the locking bar there
is a seat or abutment K. pivoted upon a pin k. To the lower end of the seat or
abutment I joint the upper end of a curved lever E fulcrumed upon the pin which
forms the centre of the locking bar. This abutment K has a lug m, which when
the locking bar is engaged with the shackle rests in a recess n of said locking bar,
and which lug when the locking bar is drawn back rests against the shoulder o of
the locking bar and holds it back, as shown in Figure 2. Now the point of contact
.of the end of the shackle bar with the abutment is. arranged to be inside of the
fulcrum pin of the abutment, so that when the shackle bar is closed its end strikes
the abutment and turns it, causing its lug m to pass off shoulder o into recess n, at
which time the tension of spring ; forces the locking bar into engagement with
the shackle.
The function of lever E is as follows:-When the locking bar is being with-
drawn from the shackle the same bit of the key which acts upon the locking bar
also acts upon the lower end of lever E, throwing it outward, and its upper end
inward, which movement it will be seen tilts the abutment K outward and raises
its lug m to a position where it rests against the shoulder o of the locking bar.
So far I have only described the construction and operation of the locking
mechanism. I will now proceed to describe the construction of the indicator
mechanism and its cooperation with the locking mechanism. F is the main
indicator wheel; it is of an annular form, and turns loosely in a seat on the
opposite side of the web or partition to the bolt mechanism. This ring or wheel
has (see Figures 4, 5, 6) a ring of teeth t upon its flat side next to the partition,
which are received in a recess in said partition, and has upon its outer face a ring
of crown teeth t¹ projecting at right angles from the periphery of the ring, while
a recess in its outer face is filled with celluloid or other equivalent material, as
shown in black in Figure 3, to give a good back-ground for the figures or letters
that are placed thereon. Meshing with the crown teeth of this wheel are three
subsidiary indicator wheels G, G1, G2, which are carried by pins that are attached
to the face plate A' on the back side of the lock. Each one of these wheels is
provided with a ring of figures or letters which show through openings in the case
for each, and the teeth of which wheels and the numbers or letters thereon are
arranged for a differential effect to prevent the easy recurrence of the same symbols.
Where the indications on the ring or annular wheel show through the case, this
face plate is depressed as at g to bring the case down to the plane of this wheel.
Now to connect these wheels with the bolt mechanism the middle plate or partition
of the case is cut away just opposite the teeth on the back of the annular dial F,
and a pawl H is jointed to the upper end of the locking bar C, and protrudes
through the opening in the middle partition, and acts upon the teeth on the back
of the indicator wheel F to move it and change the indications every time the
locking bar is withdrawn. I may not however use an articulated or jointed pawl
as shown, but may have a rigid stud or spur formed on the side of the locking bar,
which spur acts upon the teeth of the annular indicator to move it. In such case
however the locking bar must be connected with its fulcrum pin loosely, so as to
permit the slight lateral variation necessary to allow the spur to pass over the
teeth of the indicator, and the locking bar and spur will be forced against the teeth
of the indicator ring by a flat spring on the face plate. For locking the indicator
ring against being moved by other agency than the locking bar I employ an elbow
lever I fulcrumed upon the same pin with the tumbler, and the arms of which
lever are pressed upwardly by the tension of the spring r. The upper one of the
arms of this elbow lever has its end bent and extended through an opening in the
middle partition, where it engages with the teeth on the back of the indicator ring,
while its lower end rests beneath the key pin in position to be struck by the key
bit.
Now in opening the lock it will be seen that the lower bit of the key first
depresses the lower arm of the elbow lever I, and removes its upper arm from the

page_text: teeth of the main indicator wheel F. Immediately following this the opposite bit
of the key raises the tumbler D until its notch g is opposite the lug d of the
locking bar C, when the other bit of the key strikes the lower end of the locking
bar C and withdraws it from the shackle, at same time moving the indicator wheels
through the agency of the pawl above.
Now in defining the Invention more clearly, I would state that I am aware that
it is not new broadly to combine a locking mechanism acting in one plane with an
indicator mechanism acting in another plane by a pawl or jointed piece which
connects the locking mechanism with the indicator mechanism, and I do not claim
this broadly. I do not know however that an indicator wheel having teeth or
notches upon its side has ever been thus combined with the locking mechanism,
and I claim it as a novel and meritorious construction.
I will now proceed to describe a sheet metal lock case of modified construction.
Figure 9 is an inside view of the cup shaped section of the shell which carries
the locking mechanism; Figure 10 is a view of the same part with the middle
plate applied thereto; Figure 11 is a view of the middle plate opposite to that
shown in Figure 10; Figure 12 is a cross section through the line x, x, of Figure 10';
Figure 13 is an edge view of the lock case with the shackle seat in section; Figures
14 and 15 are details of the ear and shackle pin.
This part of the Invention relates to a novel construction of lock case designed
to meet the requirements of that type of indicator padlock already described, in
which the bolt mechanism and indicator mechanism are arranged in different
planes with a supporting plate between the same. The object sought is to combine
an economy in the manufacture of the case with intrinsic merit in its structure,
the principal points aimed at being the largest amount of room for the indicator
mechanism in the smallest compass of case, and such a structure of a three part case
as will avoid strain on the rivets. These ends are attained by this improved case,
which I will now proceed to describe in detail.
Referring to Figures 9 to 15 A, A1, A2, are the three parts of the case of sub-
stantially the same diameter, and connected by peripheral joints. The part A is
the back plate, and is made cup shape with a considerable rim or peripheral portion.
The part A is the intermediate supporting plate for the indicator mechanism,
which plate is more or less cut out, as shown in Figure 11, and is also made with a
peripheral rim corresponding in diameter to the rim of A, while the part A* is a
plain flat disc. All these parts are in practice made of sheet steel, and the parts A
and A' which have rims are struck up cold. The object in thus striking up these
parts from sheet metal is to ensure a uniform thickness of metal and to facilitate the .
finishing of the case. These parts of the case it will be seen are all of the same
diameter, and the two parts which are made cup shaped have the bottom edge of
one cup shaped piece fitting against the rim of the other cup shaped piece. Although
the three parts of the lock case are all cut from the same thickness of metal the
centre portions of the middle plate are afterwards reduced in thickness, except at
the edges, where the full strength of the metal is required for the rivets.
Between the parts A and A' the bolt mechanism is to be arranged, while between
A and A is contained the indicator mechanism which is carried by its supporting
plate A, and the figures on the dials of which mechanism show through suitable
holes in the face plate A³, which holes are located (as is also the key hole) at such
points as the peculiar mechanism of the lock may necessitate or render desirable.
To fasten the three parts of the case together I resort to a peculiar construction and
mode of operation. If the three parts of the case are connected by a set of rivets
of the same length, all passing through all three parts, much valuable space in the
indicator compartment is sacrificed, and the movement of the parts therein inter-
fered with, and besides, the case is weak, for diagonal blows on the lock case are
liable to make the parts grind on each other and strain the rivets. I employ but
one rivet a, which passes through the whole lock, and this fastens the part A to
A2; I attach to the back side of A, Figure 11, three short rivets b, b, b, that fasten

page_text: A to A, and to the top side of A^ I attach another short river, Figures 112,
that fastens A¹ and A* together.
Now in rivetting up these parts I first attach A' and A' by swaging the rivet c,
which can be done without strain to the parts, since both ends of the rivet are
accessible, so that one end may have a rest while the other end is being hammered.
Then I fasten these two parts A' and A¹ to A by successively rivetting a and b, b, b.
Of these rivets a it will be seen has both ends accessible so that it may have a rest
on one side while it is being hammered on the other, but the rivets b it will be
perceived rely for their resistance to the rivetting strain upon the middle plate A'.
To prevent springing this plate, which might render the indicator mechanism
inoperative, the rivets b, b, b, are placed close to the periphery where they have
the strength of the rim to sustain the strain, and they are made with broad
shoulders, and besides a greater thickness of metal is left in the plate just
adjacent to the rim (see Figures 10 and 12), so that the combined influence of
location, strength of metal, and size of shoulder permit this rivetting to be
successfully accomplished without involving any springing of the parts or other
objectionable incidents.
To prevent the parts of the case from moving over each other when struck by
an obliquely delivered blow I rebate the adjacent edges of each of the parts at
the peripheral joints, as in Figure 12, so that each part telescopes a short distance
into the next to make, when the parts are rivetted, a firm and rigid whole. For
receiving the shackle bar I construct a peculiar pocket, rivet, or fulcrum joint as
follows: The part A is formed with an opening in its rim and an ear d. I
then form separately a piece B (Figures 14 and 15) having an ear ƒ with a
'fulcrum pin which is milled to form a shoulder, and whose end passes through
a perforation in the ear d. With the separate ear f is formed a curved right
angular segment g, which, when the ears are fitted together, closes all communi-
cation between the inside of the lock and the fulcrum seat. This segment has
two lugs, which are designed to pass through two slots (h, h, Figure 9) in the
part A and be rivetted. These lugs are however not absolutely necessary, for
the sides of the segment at 1-1, Figure 14, bear against the rim of part A, see
'dotted lines, Figures 9 and 10, and prevent it from being pulled out, while shoulders
2-2, Figure 15, prevent the piece from being pushed in or moved sideways whenever
the part A is rivetted down in place, as in Figure 10, the said part A¹ having
'a hole i, Figure 11, which fits over the ear f, and cooperates with it to hold it as
just described.
Having described the nature of the said Invention, and the manner of performing
the same, I declare that what I claim as the Invention to be protected by the
herein before in part recited Letters Patent is,-
1st. An indicator lock consisting of a locking mechanism acting in one plane,
and a set of indicator wheels resting in a plane parallel to the first, one of said
indicator wheels having teeth or notches upon its back side for movement by the
direct engagement of the locking bar and combined therewith, substantially as
shown and described.
2nd. The indicator ring herein described having a set of teeth or notches on its
back side, and a set of crown teeth on the front side combined with a set of
indicator wheels engaging with these crown teeth and with a locking mechanism
engaging with the teeth or notches on the back side of said ring, as described.
3rd. The combination with a locking mechanism and the indicator mechanism
of a case composed of a middle section having a web portion or partition cast in
one piece with a peripheral rim and two face plates as described.
4th. The case composed of a middle section formed in one piece with a web
portion and peripheral rim with shoulders a, in combination with the face plates
slotted to receive the shoulders a, substantially as described.
5th. The combination with the shakle bar and the locking bar C of the pivoted
abutment or seat K and the lever E, arranged as described to throw back the
abutment and hold the locking bar back when the shackle is out.

page_text: 6th. The combination with the indicator ring having teeth upon the back side
of the locking elbow lever I located in the bolt compartment and extending through
to the indicator ring, substantially as and for the purpose described.
7th. A sheet metal lock case made of three parts of equal diameter with
peripheral joints and rabetted edges, and two of which parts are cup shaped and
the other plain, substantially as and for the purpose described.
8th. The combination of the three parts A, A, A³, of the lock case, the part A¹
having one rivetted connection with A' and one rivetted connection with A, and
the two parts A', A³, being fastened to A by an independent short rivet o passing
only through the bolt mechanism compartment, substantially as and for the purpose
described.
9th. The combination with the part A having an open place in its rim, and an
ear d of the detachable ear f having a curved segment g, the fulcrum pin and the
part A' adapted to cooperate therewith as described.
In witness whereof, I, the said Alexander Melville Clark, have hereunto set
my hand and seal, this Twenty first day of September, A.D. 1881.
A. M. CLARK. (L.S.)