Improvements in Hydraulic Rivetters.
Year: 1888

page_text: Date of Application, 29th Sept., 1888
Complete Specification Left, 28th June, 1889-Accepted, 28th Sept., 1889
PROVISIONAL SPECIFICATION.
Improvements in Hydraulic Rivetters.
A communication from VICTOR SCHÖNBACH, of Karolinenthal, in the Empire of
Austria, Engineer.
1, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex, M.I.M.E.
do hereby declare the nature of this invention to be as follows :-
This invention relates to an improvement in those hydraulic rivetters in each of
which besides a rivetting ram a second ram is employed for closing the plates. Some
of the machines hitherto known for example those constructed by Messrs. Fielding
and Platt of Gloucester, consume pressure water during the whole stroke, whereas in
the rivetter hereinafter described pressure water is used only during the active or
working part of the stroke, both rams being moved up to their working position by
means of an auxiliary piston common to both. As will be hereinafter shown this
end is attained by limiting the relative stroke of one ram in reference to the other in
such a way, that the inactive stroke is the same for both.
The auxiliary piston can be attached either to the rivetting ram or to the plate-
closing ram.
Each of these last mentioned arrangements are hereinafter described separately.
In the arrangement wherein the piston-rod of the auxiliary piston is rigidly con-
nected with the rivetting ram the closing-tool and the cupping-die are both arranged
eccentrically in reference to their respective rams. The same construction can how-
ever be applied with advantage, when both tools and their rams are arranged in the
same axis. The relative stroke of the closing ram within the rivetting-ram is limited
by a collar screwed on a rod. If the tools are arranged concentrically the motion of
the inner ram is limited by a flange attached to the outer rain. The closing-tool is of
a peculiar form being provided with a gap, which allows the rivet-head or bolt to be
swung in or out freely. The depth of this gap depends on the total stroke of the
cupping-die and the relative stroke of the closing ram, within the rivetting ram. The
total stroke of the cupping die is, as may be easily verified: St = 28 d + d
being the diameter of the rivet bolt.
The length Si =15d+ is the inactive or lost part of the stroke as during this
part of the stroke the tools are only moved up to their working position. During the
remaining or working part of the stroke Sw = St Si the rivet-head is formed.
The plate-closing tool is by the length Sw in advance of the cupping tool, and it is
evident that the depth of the gap in the closing tool must be also equal to Sw. In
order to be flush with the plates the closing tool must thus advance by the same way Si
as the cupping tool before it reaches the rivet. Both motions can therefore be per-
formed simultaneously by means of one auxiliary piston.
-
At the end of the pressure stroke the cupping-die as well as the closing tool is flush
with the plates, and it is therefore evident, that the relative stroke of both, and of
course, of their rams, also must be equal to Sw.
From what has been said it follows that the depth of the gap must be equal to the
working or useful stroke (Sw) of the cupping-dio and equal also to the relative stroke
of the closing ram within the rivetting ram.
=
1) we have =
St
Si 1.5 d
With rivets of one inch in diameter (d
= 0.6
2.8 d + T
and Swo = St.- Si = St - 0-6 St 0.4 St. viz. the working stroke is only 40 per cent.
of the total stroke. With smaller rivets the working stroke is even less, down to
30 per cent. of the total stroke.
From the preceding explanation the working of the machine will be easily under-
stood. The pressure-cylinder is preferably of gun metal and screwed into the frame,

page_text: To
the plate-closing ram moves within the rivetting ram, the parts which carry the
cupping-tool and the closing tool respectively serve also as guides for the rams.
the rivetting ram the auxiliary. piston is attached by a rod, an admission valve is pro-
vided for the large ram, and by another valve the water admitted to the auxiliary
piston as well as to the smaller or closing ram. The front side of the auxiliary
piston is in constant communication with the admission port of the valve by means of
a lateral passage, being thus always under pressure. The mode of working is as
follows: The pressure water having been admitted it passes behind the auxiliary
piston and flows through an axial boring of its piston-rod into the space between the
rivetting and cupping rams forcing them apart so that both rams henceforth act as one
piece. By a pressure corresponding to the sectional area of the piston rod both rams
are pressed forward in union through the length Si. until the closing tool reaches the
plates. During this part of the stroke the rivetting ram admission valve is put to
exhaust so that the space behind the said ram takes in waste water from the exhaust-
tube (the outfall of the exhaust being at an elevated point above the machine), thus
it is evident that during the inactive stroke Si no water from the accumulator is used
behind the rivetting ram. After the closing tool has reached the plates pressure
water is admitted by one valve to the space behind the rivetting ram (the other valve
remaining open to pressure as before). The rivetting ram is now driven forward by
a pressure corresponding to the difference of the areas of the two rams and by this
pressure the rivet head is formed. During this part of the stroke the water in the
space between both rams is in constant communication with the water behind the
rivetting rain, the pressure in both spaces being equal to the working pressure; any
water therefore, which is forced out of the space between the rams enters as driving.
water behind the rivetting ram. At the same time the closing tool is pressed against
the plates by a pressure equal to the sectional area of the closing ram." The quantity
of water consumed during this working part of the stroke is equal to the difference
of the sectional areas of the two rams multiplied by the length Sw. As the area of
the closing ram is generally 04 of the area of the rivetting ram the quantity con-
sumed will be (designing by B and C the areas of the rivetting and closing rams
respectively) Q = (B C) Sw
(B 0.4 B) Sw 0-6 B Sw and as (with
rivets of one inch) Sw ==== 0.4 St: Q == 0.6 B. 0.4 St = 0.24 B St.
=
-
-
=
In some of those hydraulic rivetters for example in those constructed by Fielding
and Platt where both rams consume pressure water during the whole stroke, the con-
sumption is Q B St. and it is evident that the consumption of the herein described
machine is only about a quarter of that. The rivet head having been formed both
the before-mentioned valves are put to exhaust and the rams are drawn back by the
pressure acting on the annular area of the front side of the auxiliary piston this side
of the piston being in constant communication with the pressure-water, as has been
shown above.
At the end of the return stroke both rams must necessarily take their original
position as will be shown presently. If the rivetting ram only is drawn back-the
closing ram remaining stationary in consequence of frictional resistance—the before
mentioned collar strikes the closing ram after the rivetting rain has inoved through
the length Sw. and both rams move in union being in their correct original mutual
position. Should however the closing ram move simultaneously with the rivetting
ram from the beginning, the shoulder of the closing tool strikes the frame after the
rams have moved through Si and stops it, the rivetting ram proceeding then alone
through the length Sw. to the end of the stroke.
In either case the distance between both rams at the end of the stroke is Sw. and
as the space between the rivetting and closing rams is in communication with the
exhaust, it is filled with waste water, so that at the beginning of the next stroke no
water has to be introduced into this space.
Besides the quantity of water already mentioned as used during the working stroke
of the rams (0.24 B St) another quantity is consumed by the auxiliary piston, this
quantity being about 0.08 0.10 B St. In a rivetter as constructed by Messrs.
Fielding and Platt two return rams are used which together consume the same
,

page_text: quantity of water as the auxiliary piston of the herein described machine. Thus the
total consumption of water during one operation is on an average 1:10 B St in the
said Fielding and Platt's hydraulic rivetter and all others of similar construction, as
against 0.33 B St in the machine herein described, which represents an economy of
70 per cent. If the water enclosed in the space between the rivetting and closing
rams is relieved from pressure the full pressure corresponding to the area of the
rivetting ram can be brought to hear upon the rivet..
In the arrangement wherein the piston-rod of the auxiliary piston is rigidly attached
to the plate-closing ram, the relative stroke of the closing ram within the rivetting ram
is again equal to Sw; the closing ram is prevented from moving further on by the
shoulder of a thicker part of the auxiliary piston rod, which shoulder comes in contact
with the said rivetting ram. The closing tool in this construction is without a gap,
both tools standing in their initial position at the same distance from the plates. The
economy of water-consumption is less than in the other arrangement herein before
described; on the other hand this second construction is somewhat simpler if-as
usual-the rams are placed out of line with the tools, as parts necessary in such
former arrangement are in this one dispensed with. Another advantage is the absence
of the gap in the closing tool and the possibility of using the closing ram as the
rivetting ram for light work the closing tool being replaced in this case by a
cupping die.
The machine works in the following way:
At the beginning both tools are flush with one another, the two valves being both
put to exhaust. The auxiliary piston pressure water is admitted and by means of the
axial passage in the piston rod it is also admitted to the space between the two rams.
The closing ram yields to the pressure and moves on until the before mentioned
shoulder strikes the rivetting ram. At this moment the closing tool is by Sw in
advance of the cupping die. In consequence of the internal pressure within the
space between the rams the closing ram is rigidly united with the rivetting ram, both
rams forming practically one piece.
By the pressure acting on the auxiliary piston both rams advance now in union
through the length Si until the closing tool reaches the plates, whereas the cupping
die just touches the rivet shaft being at the distance Sw from the plates. Both rams
have thus moved through the length Si by the sole action of the auxiliary piston and
with a water consumption corresponding to the area of this piston only, as the space
behind the rivetting ram has been filled by waste water.
The rains having reached a certain position pressure water is admitted to the back
of the rivetting ram and the rivet head is formed by the cupping die advancing
through the length Sw. The total forming pressure corresponds to the difference of
the areas of the two rams and as the water pressed out of the diminishing space
between the two rams enters the increasing space behind the rivetting ram being thus
completely utilised the consumption of the pressure water is B Sw = 0.4 B St.
The rivet having been formed both valves are put to exhaust and by the pressure
acting on the annular front area of the auxiliary piston the rams are drawn back. If
the space between the two rams is relieved froin pressure the total area of the
rivetting ram can be used for bringing an extra strong pressure to bear on the
rivet.
If the closing tool is replaced by a cupping die the closing ram can be used as a
rivetting ram for light work. As the consumption of water for operating the auxiliary
pision is equal to about 014 B St the total consumption during one operation is
0.40 B St + 0.14 B St: 0.54 B St which, as compared with the consumption of the
rivetters hitherto known (11 B St) represents an economy of 50 per cent.
Dated this 29th day of September 1888.
=

page_text: COMPLETE SPECIFICATION.
Improvements in Hydraulic Rivetters.
A communication from VICTOR SCHONBACH, of Karolinenthal, in the Empire of
Austria, Engineer.
I ALFRED JULIUS BOULT of 323 High Holborn, in the County of Middlesex,
M.I.M.E., 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 :-
This invention relates to an improvement in those hydraulic rivetters in each of
which besides a rivetting ram a second ram is employed for closing the plates. Some
of the machines hitherto known for example those constructed by Messrs. Fielding and
Platt of Gloucester consume pressure-water during the whole stroke, whereas in the
rivetter hereinafter described pressure water is used only during the active or working
part of the stroke, both rams being moved up to their working position by means of
an auxiliary piston common to both.
As will be hereinafter shown, this end is attained by limiting the relative stroke of
one ram in reference to the other in such a way, that the inactive stroke is the
same for both.
From the dependence of the relative stroke of one ram in reference to the other it
is possible to set the two rivet-heads at one stroke.
The auxiliary piston can be attached either to the rivetting ram or to the plate-
closing-ram.
Each of these last mentioned arrangements are hereinafter described separately.
The arrangement wherein the piston-rod of the auxiliary piston is rigidly connected
with the rivetting-ram is shown by the cross-section in fig. 1 sheet 1 of the accom-
panying drawings. In this figure the closing-tool and the cupping die are both
arranged eccentrically in reference to their respective rams. The same construction
can, however, be applied with advantage when both rams and tools are arranged in
the same axis. The relative stroke of the closing-ram C within the rivetting ram B
is limited by the collar m, screwed on the rod l. If the tools are arranged concen-
trically the motion of the inner ram C is limited by a flange attached to the
outer ram B.
The closing tool k is of a peculiar form being provided with a gap, which allows
the rivet head or bolt to be swung in or out freely. The depth of this gap depends
on the total stroke of the cupping-die and the relative stroke of the ram within the
ram B. This will be easily understood by referring to the figures I. II. III. I
shows the position of the tools when both rams are drawn back, the rivet to be
formed being already inserted in the cup of the back-frame. The total stroke of the
cupping die is, as may be easily verified, st = 2.8 d +, d being the diameter of the
The length si 15 d is the inactive or last part of the stroke, as during
this part of the stroke, the tools are only moved up to their working position. During
the remaining or working part of the stroke sw =st -
si the rivet head is
formed.
rivet bolt.
=
The plate-closing tool is by the length su in advance of the cupping die, and it
is evident that the depth of the gap in the closing-tool must at least be equal to sw.
In order to be flush with the plates the closing-tool must thus advance by the same
way si as the cupping-tool before it reaches the rivet. Both motions can therefore be
performed simultaneously by means of one:auxiliary piston..
At the end of the pressure stroke the cupping die as well as the closing-tool is flush
with the plates, and it is therefore evident, that the relative stroke of both, and of
course, of their rams must be equal to sw.
1II shows, the initial position, it also shows how the rivet is swung in between the
cupping die and the closing-tool through the gap of the latter.

page_text: From what has been said it follows that the working or useful stroke (sw) of the
cupping-die must be equal to the relative stroke of the ram C within the ram B.
1.5 d
With rivets of one inch in diameter (d == 1) we have
sto = st -
st ·2·8d+ T
=
0.6 and
sist06 st = 04 st viz. the working stroke is only 40 per cent. of
the total stroke. With smaller rivets the working stroke is even less down to 30
per cent. of the total stroke.
From the preceding explanation as well as from fig. 1 the working of the machine
will be easily understood. The pressure cylinder A is preferably of gun metal and
screwed into the frame. B is the large cupping-ram, C the plate-closing-ram which
moves within the ram B; the parts b and c which carry the cupping tool and closing
tool respectively serve also as guides for the rams.
To the ram B the auxiliary piston H is attached by the rod D. S is the admission-
valve for the large ram B, whereas by the valve S₁ the pressure water is admitted to
the auxiliary piston H as well as to the smaller ram C. The front side of the auxiliary
piston is in constant communication with the admission port of the valve by means of
the lateral passage a, being thus always under pressure. The mode of working is as
follows: The pressure water having been admitted by the valve S¹, it passes behind
the piston H and flows through the axial boring of the piston-rod D into the space
between the rains B and C and thus forces them apart from each other, so that both
rams henceforth act as one piece.
By a pressure corresponding to the sectional area of the piston-rod D both rams
are pressed forward in unison through the length si until the closing-tool reaches
the plates.
During this part of the stroke the valve S is put to exhaust so that the space
behind the ram B takes in waste-water from the exhaust-tube (the-outfall of the
exhaust being at an elevated point above the machine) thus it is evident that
during the inactive stroke si no water from the accumulator is used behind the
ram B.
After the closing-tool has reached the plates pressure-water is admitted by the
valve S to the space behind the ram B (the valve 'S' remaining open to the pressure
as before).
The ram B is now driven forward by a pressure corresponding to the difference of
the areas of B and C and by this pressure the rivet-head is formed. During this part
of the stroke the water in all the space between both rams is in constant communica-
tion with the water behind the ram B, the pressure in both spaces being equal to the
working-pressure, any water, therefore, which is forced out of the space between the
rams enters as driving-water behind the ram B. At the same time the closing-tool is
pressed against the plates by a pressure equal to the sectional area of the ram C. The
quantity of water consumed during this working-part of the stroke is equal to the
difference of the sectional areas of B and multiplied by the length sw. As the
area of C is generally about 0'4 of the area of B, the quantity consumed will be
(designing by B and the areas of the rivetting and closing rams respectively:
0.6 B sw,
0.4 B) 810 =
and as (with rivets of about one
0-6 B. 04 st = 0.24 B st.
=
(B
-
C)820 = (B
inch) sw = 04 st: Q
1
-
In some of those well known hydraulic rivetters for example those constructed by
Fielding and Platt, where both rams consume pressure water during the whole stroke;
the consumption is Q₁ B st, and it is evident, that the consumption of the herein
described machine is only about a quarter of that.
-
The rivet-head having been formed both the valves S and S are put to exhaust and
the rams are drawn back by the pressure acting on the annular area of the front side
of the piston H, this side of the piston being in constant communication with the
pressure-water, as has been shown above.
At the end of the return-stroke both rams must necessarily take their original
position, as will be shown presently.
If B only is drawn back, C remaining stationary in consequence of frictional
resistance the collar m strikes the ram C, after B has moved through the length sw,

page_text: and then both rams move in union being in their correct original mutual position.
Should, however, C move simultaneously with B from the beginning, the shoulder of
the closing-tool strikes the frame, after the rams have moved through the length si,
and stops it, B then proceeding alone through the length sw to the end of the stroke.
In either case the distance between both rams at the end of the stroke is sw, and as 5
the space between B and C is in communication, with the exhaust, it is filled with
waste-water, so that at the beginning of the next stroke no water has to be introduced
into this space.
Besides the quantity of water already mentioned as used during the working stroke
of the rams (0.24 B st) another quantity is consumed by the auxiliary piston, this 1
quantity being about 0.08 0.10 B st.
-
In a rivetter as constructed by Messrs. Fielding and Platt, two return-rams are
used, which together consume the same quantity of water as the auxiliary piston of
the herein described machine.
Thus the total consumption of water during one operation is on an average 11 B st 1
in the said Fielding and Platt's hydraulic rivetter and all others of similar construc-
tion as against 0.33 B st in the machine herein described, which represents an economy
of 70 per cent.
If the water enclosed in the space between B and C is relieved from pressure, the
full pressure corresponding to the area of the ram B can be brought to bear upon 2
the rivet.
For forming both rivet heads at one stroke, only the total stroke st of the cupping
die requires to be equal to 2 st¹, if st is here the total stroke in reference to one
head.
In this case st₁ = 2d
st¹ =
st=
2 d + ¾/
2.8 d + g
1.5 st.
whilst in the former case st = 28 d therefore 2
st and with rivets about one inch we have sti
=
0.75 st therefore
Figures 1-6 sheet 2 of the accompanying drawing shows the different positions
during the rivetting. Fig. 1 shows the initial position with the rivet (which is cut
exactly to the desired length) swung in between the cupping dies through the gap of a
the closing-tool.
When the plates are brought close to the closing-tool as in fig. 2 the space between
the plates and the movable cupping tool is equal to the length of the rivet bolt, which
gives the material for one rivet-head.
When the valve S is put to admission the cupping-die and the closing tool advance a
in union, until the rivet bolt reaches the fixed cupping-tool as in fig. 3. If the length
of the rivet bolt be correct, the bolts which overhang the plates must be of the same.
length. Next pressure-water is admitted to the back of the piston B by the valve S
and because the closing-tool offers no resistance, the closing-tool advances with the
cupping-die and the rivet-head on the fixed cupping-tool is formed as in fig. 4. 4
Experience shows, that no material passes through the plates to the other side, but the
rivet-bolt will be chained and prevent an overflow of the material.
When this head is formed on the fixed tool, the closing-tool is then in close contact
to it, and the plates are pressed together and during this pressing the second rivet
head is formed in the former described way with the difference of the pressures of the 4
rivetting ram and plate closing-ram see fig. 5.
Fig. 6 shows again the initial position.
The principal features of this way of rivetting are..
1.) The inactive strokes are executed with the auxiliary piston.
2.) The two rivet heads are formed at one stroke but not simultaneously.
3.) The plate closing is in no way altered, while the first rivet head always will be
formed on the fixed tool at the back-frame.
4.) No special apparatus is required for this mode of working.
The consumption of pressure-water when so working the rivetter is as follows:-
The quantity consumed by the auxiliary piston is about
During the farming of the
0.09 B St
91
-
-
L
0.18 B st.

page_text: 98
=
-
C) sw =
(B
Bs, and during the forming or the second head g
06 sw B. The inactive stroke for one head is here s¹i = 0.7 d + 3r and for rivets
about one inch si = 11 d therefore
=
sti 1.1 d
3't 2.4 d
-
0.46 and swo
=
(10.46) = 0.54 s¹t.
1
sts'is't —¨
The total quantity of pressure-water is therefore for rivets of about one inch
Q 91 + 2 + 493 = B s¹t (0.18 +0.54 + 0.324) Q: 1044 Bt and while-
as has been shown above s¹t = 0.75 st Q = 0.78 B st (st is the total stroke by
the ordinary way of rivetting).
-
Thus the total consumption of pressure-water during the forming of two rivet-heads
is still 30 per cent. less than the consumption in the machines hitherto known (1·1 B st)
for forming only one head.
The arrangement wherein the piston rod of the auxiliary piston is rigidly attached
to the plate-closing-ram C is shown in fig. 2 (sheet I).
The relative stroke of the closing-ram C within the rivetting-ram B is limited by
the shoulder of the thicker part D of the rod D, which shoulder comes in contact
with the ram B.
The relative stroke is therefore equal to sw max: for the thickest rivets. The limit
of the relative stroke of both the rains C and B can be effected in another way, so that
in either case the relative stroke is equal to sw suitable to the corresponding
rivet.
The closing-tool in this construction is without a gap. The economy of water-con-
sumption is less than with the other arrangemnt herein before described; on the
other hand this second construction allows of the ram C being used as a rivetting ram
for light work, the closing tool k being replaced in this case by a cupping-die.
The machine works in the following way :-
At the beginning both tools are in the position I fig. 2 of sheet I. The valves S
and S being both put to exhaust.
Next behind the piston H pressure water is admitted by the valve S' and, by means
of the axial passage in the rod D it is also admitted to the space between the ram B
and C. The ram yields to the pressure and moves on until the shoulder of D¹
strikes the ram B. At this moment the closing-tool is by sw in advance of the
cupping-die see position II in fig. 2 of sheet 1. In consequence of the internal
pressure within the space between the rams the ram C is rigidly united with B, both
rams forming practically one piece.
By the pressure acting on the auxiliary piston H both rams advance now in union
through the length si until the closing-tool k reaches the plates as in the position III
in fig. 2 of sheet I, whereas the cupping-die just touches the rivet-shaft, being at the
distance sw from the plates.
Both rains have thus moved through the length si by the sole action of the
auxiliary piston and with a water-consumption corresponding to the area of this piston
only as the space behind the rivetting-ram B has been filled by waste-water entering
through the valve S.
The rams having reached the position III pressure-water is admitted through the
valve S to the back of the ram B and the rivet-head is formed by the cupping-die
advancing through the length st. The total forming-pressure corresponds to the
difference of the areas of B and C, and as the water pressed out of the diminishing
space between B and Centers the increasing space behind B, being thus completely
utilised the consumption of pressure-water is B sw = 04 B st.
The rivet having been formed both valves are put to exhaust and by the pressure
acting on the annular front-area of the piston H the rams are drawn back.
If the space between B and C is relieved from pressure, the total area of the ram B
can be used for bringing an extra-strong pressure to bear on the rivet.
If the closing-tool is replaced by a cupping-die the ram C can be used as a
rivetting-ram for light work. As the consumption of water for operating the
auxiliary piston H is in this manner of working equal to about 0.14 B st, the total

page_text: consumption during one operation is 0.4 B st, + 0.14 B st = 0.54 B st, which, as
compared with the consumption of rivetters such as those, constructed by Fielding &
Platt 11 B st represents an economy of 50 per cent.
The manner in which the two rivet-heads are set at one stroke by this construction
is similar to the manner herein before described with reference to the other arrange-
ment, only with this difference, that the plate-closing-tool and the cupping-die have in
their initial positions not yet reached that relative position, which is necessary to the
exact distribution of the material.
This position is attained, when the thicker part D¹ of the rod of the auxiliary
piston strikes the rivetting-ram B, or when the relative stroke of the two pistons (
and B is limited, in another way. In this position the plate closing-tool is by the
lengths in advance of the cupping-tool.
The figures 7-12 of the sheet II of the drawings shows the different positions
during the rivetting.
In the fig. 7 both tools are in their initial positions, the plates with the rivet bolt
are swung
in and the plates are brought close to the closing tool. The valve S¹ is put
to admission, and the closing-tool advances alone until the relative stroke of C within
B is limited see figure 8. From this moment the closing tool advances in union with
the cupping-die until the rivet bolt is in contact with both cupping dies as in figure 9.
In this position the same quantity of material is distributed to both sides of the
plates.
Now the valve S is put to admission the rivet head in the cup of the back frame is
formed by the rain B as shown in figure 10 and the plates have been pressed together
and during this pressing the second head is formed as in figure 11 by the pressure
corresponding to the difference of B and C.
Figure 12 shows again the initial position.
=
=
=
=
=
Pressure water is used. By the ram C during the motion of the closing tool alone
the quantity q Cs w by the auxiliary piston the quantity 92 0.14 BS¹t=
0.28 Bst by the rau B during the forming of the first head q Bs and during
the forming of the second head q (B-C) s¹ w. The total consumption is there-
fore Q 9² + 9 +93 +94 and with rivets about one inch Q = Bst (0.4 x 0.54
+0.28 +054+0.6 × 0.54) Q = 1.36 Bs t and because s¹ t 0.75 st
1.02 Bst. Therefore by this operation of forming both rivet heads the con-
sumption of pressure water is yet less than that consumed in machines hitherto known
(11 Bst) which form only one head.
Q
=
-
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me by my
foreign correspondent, I declare that what I claim is :-
1. In hydraulic rivetters, where besides a rivetting-ram another ram is used for
closing the plates: the combination of the closing-rain with the rivetting-ram in such
a way, that the closing-ram in reference to the rivetting-ram can move only through
a length so which is equal to the working stroke of the cupping-die during the actual
forming of the rivet-head, both rams being arranged in such a manner, that after the
closing-ram has moved within the rivetting-ram through the aforesaid length sur, both
rams move in union being held rigidly together, by the internal pressure of the water
and thus forming practically one piece; these rams being actuated by one auxiliary
piston and thus moved together through a length si, corresponding to all the inactive
part of the stroke; the piston rod of the auxiliary piston being rigidly attached
either to the rivetting ram or to the closing-ram, substantially as described and illus-
trated in the accompanying drawings.
2. In a hydraulic rivetting-machine, such as herein before described the use of a
peculiar form of the closing-tool, this tool being provided with a gap of a depth at
least equal to the way through which the cupping-die moves during the actual
formation of the rivet-head, substantially as described and illustrated in the accom-
panying specification.

page_text: 3. In hydraulic rivetters such as hereinbefore described the setting without
special apparatus and with a minimum consumption of pressure-water of two rivet-
heads at one stroke at different times in such a way, that the first head is formed by
the cupping-die of the back-frame, that hereon the plates were pressed together and
during this pressing the second head is formed.
Dated this 08th day of June 1889
W. P. THOMPSON & BOULT,
Agents.