1. While letters patent for a combination are not infringed if a
material part of it is omitted, yet if a part which is only
formally omitted is supplied by a mechanical equivalent performing
the same office and producing the same result, they are
infringed.
2. The courts in this country cannot declare that any one of the
elements entering into such a combination is immaterial. They can
only decide whether a part omitted by the alleged infringer is
supplied by an equivalent device.
3. Reissued letters patent No. 5808, granted March 24, 1874,
being a reissue of original letters No. 109,372 granted Nov. 22,
1870, to Phinehas Ball, and Benaiah Fitts, for an improvement in
liquid meters, are not infringed by letters patent No. 144,747,
granted Nov. 18, 1873, to Henry A. Desper, for an improvement in
fluid meters.
The facts are stated in the opinion of the Court.
MR. JUSTICE BRADLEY delivered the opinion of the Court.
This is a bill in equity filed by the Union Water Meter Company,
the appellant, to restrain the infringement of a patent and for an
account of profits and damages. The letters patent alleged to be
infringed are reissued letters No. 5806, being a reissue of
original letters patent No. 109,372, granted 22d
Page 101 U. S. 333
November, 1870, to Phinehas Ball and Benaiah Fitts for certain
improvements in water meters; the reissue being made to the
complainant as assignee, on the 24th of March, 1874. The
defendants, by their answer, deny that the reissued patent was for
the same invention described in the original; aver that the
invention claimed was covered by another patent granted 20th July,
1869, to the same patentees, Ball and Fitts; deny that they were
the first and original inventors of the alleged improvement,
specifying various older patents in which, as they allege, it was
described, and divers persons who had known and used it; deny
infringement; and aver that all water meters made by the defendants
are constructed according to letters patent No. 144,747, granted
18th November, 1873, to Henry A. Desper, one of the defendants,
except in the omission of a certain adjusting screw.
The water meter which is the subject of the patent consists of
two parallel horizontal cylinders, each traversed by two pistons,
connected together by a connecting rod of such length that when one
piston is at one end of the cylinder the other is at a sufficient
distance from the other end, to leave the requisite space to be
filled with the quantity of water to be measured at each stroke.
This water being discharged, the pistons are made to traverse the
cylinder and allow the opposite end to be filled with water, and
discharged in like manner. By this reciprocating motion of the
pistons, regulated quantities of water are constantly received and
discharged into and out of the two ends of the cylinder
alternately. The pressure of the water from the source of supply,
admitted by means of proper valves, gives to the pistons this
reciprocating motion. The valve gear between the two parallel
cylinders is so arranged as to cause the pistons in one cylinder to
move in an opposite direction from those in the other. A rotary
valve is used for both cylinders, situated between and below them,
being circular, or funnel shaped, having holes, or ports, in its
side for the induction and eduction of the water into and out of
the cylinders, and being crowned with a bevel gear to give it a
circular motion. Across and over the valve, extending from one
piston rod to the other, is placed a shaft, having a crank at each
end, and a bevel pinion near one of the cranks, meshing into
the
Page 101 U. S. 334
bevel gear of the valve; the two cranks are arranged at right
angles with each other, and each has a crank pin which is inserted
in a slot made in the centre of the piston rod with which it is
connected -- the side of the cylinder being removed, or open,
between the end portions that receive the water. The slot which
receives the crank pin is perpendicular, and at right angles with
the length of the piston rod, and is wider than the diameter of the
pin, and enlarged in the middle in order to give the pin room, and
allow the crank to turn freely over after the piston has been
stopped. The pistons are prevented from coming into contact with
the ends of the cylinders by means of adjusting stops, slightly
projecting therefrom inside. Projecting stops for arresting the
movement of the pistons, and much of the mechanical arrangement
between the crankshaft and the slots in the piston rods, used for
giving the proper motion to the crankshaft, are to be found
described in a patent granted to Mr. Ericsson in 1851 for a water
meter having slide valves instead of a rotary valve, but in which a
rotary motion was communicated to the indicator.
The patent in question does not cover any of the separate parts
of the meter, it being conceded that these were all known and used
before the application for the patent. The claim relied on by the
complainant is for a combination only, being the fourth claim in
the reissued patent, which is in the following words:
"4. The combination in a liquid meter of the following
instrumentalities, to wit, a rotary valve
g, provided with
suitable ports or openings, through which the liquid to be measured
can be supplied to the meter and discharged therefrom; two
cylinders,
b and
b', for the reception and
measurement of the liquid; the double acting pistons
c and
c', each carrying a rod
d, and each of these
provided with a single cam slot
e, arranged as described,
and of a width greater than the diameter of the wrist
n of
the crankshaft, so as to permit of the adjustment of the pistons,
that they may discharge at each stroke, as nearly as possible, the
exact quantity of water required of them, and so as to allow each
of the crank wrists
n freely to pass its dead centre after
its own piston has ceased to act on it; adjusting stops
o,
by means of which the adjustment of the length of the stroke of the
pistons at either end is effected;
Page 101 U. S. 335
and lastly a crankshaft i, through which motion from the pistons
is imparted to the valves, the whole operating in the manner
substantially as described."
The combination here claimed consists of five parts or elements,
viz., 1st, the rotary valve; 2d, the two cylinders; 3d,
the double acting pistons, connected by a rod having a cam slot at
right angles with the length of the rod; 4th, the adjusting stops;
5th, the crankshaft with its pinion, and cranks, by means of which
rotary motion is imparted from the pistons to the valve. The rotary
valve, and the combination of the cylinders, piston rods,
crankshaft, and rotary valve were the subjects of a previous patent
granted to Ball and Fitts on the 20th of July, 1869. The only
additional elements in the present patent are the adjusting stops
and the rectangular position of the slots in the piston rods.
It is a well known doctrine of patent law, that the claim of a
combination is not infringed if any of the material parts of the
combination are omitted. It is equally well known that if any one
of the parts is only formally omitted, and is supplied by a
mechanical equivalent, performing the same office and producing the
same result, the patent is infringed.
The first question, therefore, is whether the defendants
infringe the claim referred to -- whether they do, in fact, in
their water meters, use all the parts of the combination above
specified.
The meter manufactured by the defendants is different in several
respects from that described in the complainant's patent. It has a
rotary valve like the latter, but without any bevel gear; it also
has two cylinders, with an immaterial difference of position, being
placed at right angles with each other instead of being parallel;
each cylinder is likewise provided with two double acting pistons,
connected by a piston rod, the same as in the complainant's meter;
the cylinder heads are also furnished with Ericsson's stops
projecting inside for arresting the movement of the pistons, though
these stops are fixed and not adjustable. But the meter of the
defendant's has no crankshaft, and no semblance of a crankshaft,
for imparting motion from the pistons to the rotary valve; on the
contrary, their valve is connected directly with the piston rods in
the following
Page 101 U. S. 336
manner; the piston rods cross each other at right angles, having
transverse slots, and being halved together, one lying immediately
on the other, so that the axes of the pistons are in the same
plane. The valve below is connected directly with the piston rods
by a single crank which is keyed on to its upper solid stem, and
has a crank pin which works in the two slots of the respective
piston rods. Thus arranged, the successive reciprocating movements
of the two double pistons impart a circular motion to the valve,
which, by duly arranged induction and eduction ports, alternately
fills and empties the respective cylinders.
From this it appears that, in the construction of defendants'
meter, the crankshaft, with its two cranks, pinion, and gearing
connection (which is an essential feature of the complainant's
meter), is altogether dispensed with. The defendants effect the
desired result of communicating rotary motion to the valve without
any such shaft, or any thing equivalent thereto. The entire part,
with all its appurtenances, is thrown out of their machine. They
use a crank, it is true; but it is attached directly to the rotary
valve, and is a part of it. The use of a crank in converting
reciprocating into rotary motion is an old device. It was applied
to the steam engine a century ago, and has been applied to hundreds
of different machines since that time. Ball and Fitts had no claim
to it, but only to the particular method and device by which they
employed it, in combination with the various other parts of their
meter. Instead of the crankshaft, had they in their patented
combination claimed every method, and all methods, of communicating
motion from the piston rods to the rotary valve by means of a
crank, the defendants' meter would have been an infringement. But
such a claim might not have been valid. At all events, it was not
allowed.
The specification was evidently drawn with great care, and it is
to be presumed that the patentees claimed all that the Patent
Office considered them entitled to. We cannot say that the
crankshaft was an immaterial part of their combination. The patent,
as it stands, occupies very narrow ground. It requires the presence
of every one of the elements specified in the combination secured
by it. We think that the defendants
Page 101 U. S. 337
do not use all of these elements, but that they dispense with
one of them at least which is material in the complainant's meter.
Our conclusion, therefore, is, that they do not infringe the
complainant's patent.
It may be observed, before concluding this opinion, that the
courts of this country cannot always indulge the same latitude
which is exercised by English judges in determining what parts of a
machine are or are not material. Our law requires the patentee to
specify particularly what he claims to be new, and if he claims a
combination of certain elements or parts, we cannot declare that
any one of these elements is immaterial. The patentee makes them
all material by the restricted form of his claim. We can only
decide whether any part omitted by an alleged infringer is supplied
by some other device or instrumentality which is its equivalent. We
think no such equivalent is supplied in this case. The general
construction of the defendants' meter, and the arrangement of its
parts, are so different from that described in the complainant's
patent, and claimed therein, that the defendants are enabled to
dispense with the entire part referred to.
Decree affirmed.