1. The substantial equivalent of a thing is, in the sense of the
patent law, the same as the thing itself. Two devices which perform
the same function in substantially the same way, and accomplish
substantially the same result, are therefore the same, though they
may differ in name or form.
2. The combination, consisting of a fixed knife with a striker
and the other means employed to raise the striker and let it fall
to perform the cutting function, embraced by letters patent No.
146,774, issued Jan. 27,1874, to Merrick Murphy, for an improvement
in paper bag machines, is substantially the same thing as the
ascending and descending cutting device embraced by letters patent
No. 24,734, issued July 12, 1859, to William Goodale.
The Union Paper Bag Machine Company, assignee of William
Goodale, to whom letters patent No. 24,734, for an improvement in
machines for making paper bags, were issued July 12, 1859, and
subsequently extended, brought this suit to restrain Merrick Murphy
and R. W. Murphy from infringing said letters. The respondents
justified under letters patent No. 146,774, issued Jan. 27, 1874,
to Merrick Murphy.
Page 97 U. S. 121
The court below dismissed the bill, whereupon the complainants
appealed here.
The remaining facts are stated, and the respective machines
described, in the opinion of the Court.
MR. JUSTICE CLIFFORD delivered the opinion of the Court.
Rights secured to an inventor by letters patent are property
which consists in the exclusive privilege of making and using the
invention, and of vending the same to others to be used, for the
period prescribed by the Patent Act, and the provision is that
every patent and any interest therein shall be assignable in law by
an instrument in writing. Rev.Stat., secs. 4884, 4898.
Letters patent No. 24,734, bearing date July 12, 1859, were
granted to William Goodale for new and useful improvements in
machinery for making paper bags, as more fully described in the
specification. Patents at that date were granted for the period
only of fourteen years, but the record shows that the same was duly
extended for the further term of seven years from the expiration of
the original term, and that the patentee, on the 14th of July, two
days subsequent to the extension of the patent, by an instrument in
writing, sold and assigned all his right, title, and interest in
the patent to the complainants, who instituted the present suit.
What they charge is that the respondents are making and using the
patented improvement the title to which they acquired by virtue of
the aforesaid written assignment.
Service was made and the respondents appeared and filed an
answer, setting up several defenses, all of which are abandoned
except the one denying the charge of infringement. Proofs were
taken and the circuit court, having heard the parties, entered a
decree dismissing the bill of complaint. Prompt appeal to this
Court was taken by the complainants, and they now assign for error
the decree of the circuit court in dismissing the bill of
complaint, it being conceded that it was dismissed upon the ground
that the charge of infringement was not proved.
Page 97 U. S. 122
Machines for making paper bags are old, as both sides admit, and
the evidence in this case shows that they have been constructed by
many persons and in various forms for more than twenty years and
with more or less utility. Neither party in this case claims to be
the original and first inventor of an entire machine of the kind,
nor could such a claim, if made, be sustained, in view of the
admitted state of the art. Improvements in various parts of such a
machine are claimed by the assignor of the complainants, but
inasmuch as the charge of infringement is confined to the first
claim of the patent, it will be sufficient to describe the nature
and operation of the principal device embodied in that claim,
without attempting to give any minute description of the other
parts of the machine.
Seven claims are annexed to the specification, the one in
question being described in substance and effect as follows: making
the cutter which cuts the paper from the roll in such form that in
cutting off the paper it cuts it in the required form to fold into
a bag without further cutting out.
Such a machine, of course, has a frame which supports all its
parts, and it also has a table to support the paper as it is
unwound from the roll and moved forward under the cutter. Prior to
the operation, the roll is prepared, being of the proper width to
fold lengthwise and form the bag. Feed rollers are arranged in the
machine, for moving the paper under the cutter as it is unwound
from the roll, the cutter being attached to a horizontal bar, and
working within vertical guides erected on opposite sides of the
machine. Operating vertically, as the cutter does, it will be
sufficient to state that it derives its upward movement from two
cams on a constantly rotating horizontal shaft, and that it
descends by its own weight, which is sufficient to cause the
cutting of the paper by the cutter, the descent taking place during
the intermissions between the feeding movements of the paper.
Devices and means for forming the bag of the desired length and
width are also shown in the specification and drawings, together
with the devices and means for effecting the side lapping over the
device called the former, and the devices and means for pasting one
edge of the same by passing it over a paste roller, which causes it
to adhere so as to form the seam when
Page 97 U. S. 123
the edges of the blank are folded over by the lappers. Both the
sides of the blank, so called, and the lap at the bottom are pasted
by the means described in the specification, but it is unnecessary
to enter into these details in this investigation, as the charge of
infringement is limited to the first claim.
Evidence of a satisfactory character is exhibited to show that
the assignor of the complainants was the first person to organize
an operative machine to make paper bags from a roll of paper in the
flat sheet by a transverse cut across the same with a knife having
five planes, so that the blanks, so called, when cut and folded,
will present a paper bag of the form and description given in the
specification and drawings of the patent.
Wide differences exist in the arrangement of the devices
composing the operative parts of the respondents' machine in
question, from those exhibited in the machine of the complainants;
but the frames are not substantially different, and the machine of
the respondents has two uprights which afford bearings for the
shaft and for the roller on which the paper is wound, and for two
sets of feed rollers which perform the same function as the feed
rollers in the complainants' patent. Instead of the cutter arranged
to ascend and descend, as described in the complainants'
specification, the respondents have a knife with a serrated edge,
which is attached to the bed beneath the shaft on a line with the
feed rollers, lying on its side, so that the paper, when moved by
the rollers, will pass freely over it, as it extends slightly
beyond the edge of the bed. Being attached to the bed, the knife,
though it is substantially in the form of the cutter employed in
the complainants' machine, neither rises nor falls, nor would it
perform any function whatever in the machine were it not for the
striker, which is a straight piece of metal with a blunt edge made
to revolve with the shaft, which, by the aid of certain other
devices, first causes it to rise, and then throws it sharply down
in such a manner that it makes a vertical blow upon the paper,
causing the knife to sever it as effectually as the cutter does in
the complainants' machine, showing that the two devices, to wit,
the knife and the striker, operating together, perform the exact
same function as that performed in the complainants' machine by the
ascent and descent of the cutter.
Page 97 U. S. 124
Argument to show that the form of the knife and the cutter are
substantially the same is quite unnecessary, as that is proved to a
demonstration by a comparison of the two devices. Nor can it make
any difference that the cutter is made to cut the paper by its own
gravity, while the knife is made to cut by the fall of a device
which performs no other function than to fall upon the paper at the
proper moment, and cause the stationary knife to cut for the same
purpose.
Decided support to that proposition is found in the testimony of
the expert witness examined for the complainants. He testifies that
he finds in the patent of the respondents the representation of a
cutter for forming paper bags, so shaped that, in the operation of
separating the blanks from the roll of paper in the formation of
bags, it will perform the same function as the cutter in the
complainants' machine, giving as his reason for the conclusion that
the serrated edge of the knife, as it is there called, is so shaped
as to form a blank for the bags, so that the seam may be made in
the middle of the bag, and that the bottom is provided with a lap
so that both parts may be firmly pasted together, and the top
provided with a lip for the convenience of opening the bag when it
is used.
Explanations of a valuable character are also made by the same
witness in respect to the particular form of the knife employed by
the respondents in their machine when used to form the lip at the
top or bottom of the bag. Speaking of the fact that the knife used
by the respondents has serrations or teeth of different degrees of
depth, he says that their outer points all coincide with the same
straight line across the paper, and that the operation of cutting,
when it has progressed to the depth of the small teeth in the
knife, becomes substantially the same as that performed by the
cutter in the complainants' machine, for the reason that the rest
of the cutting is continued by a series of cutting edges that have
a lap at the bottom and a lip at the top, or, in other words, the
cutting that is commenced in a straight line ceases as soon as the
small teeth cease to cut, and then the coarser teeth continue the
cutting operation down to their full extent, and constitute a
cutter substantially like the one employed in the complainants'
machine.
Suppose the explanation last given is too theoretical for
practical
Page 97 U. S. 125
application, still we are all of the opinion that the knife and
the striker employed by the respondents perform substantially the
same function as the cutter in the complainants' machine, with the
devices for raising it up and letting it drop upon the paper as it
is moved forward by the rollers.
Except where form is of the essence of the invention, it has but
little weight in the decision of such an issue, the correct rule
being that in determining the question of infringement, the court
or jury, as the case may be, are not to judge about similarities or
differences by the names of things, but are to look at the machines
or their several devices or elements in the light of what they do
or what office or function they perform and how they perform it,
and to find that one thing is substantially the same as another if
it performs substantially the same function in substantially the
same way to obtain the same result, always bearing in mind that
devices in a patented machine are different in the sense of the
patent law when they perform different functions or in a different
way, or produce a substantially different result.
Nor is it safe to give much heed to the fact that the
corresponding device in two machines organized to accomplish the
same result is different in shape or form the one from the other,
as it is necessary in every such investigation to look at the mode
of operation or the way the device works, and at the result, as
well as at the means by which the result is attained.
Inquiries of this kind are often attended with difficulty, but
if special attention is given to such portions of a given device as
really does the work, so as not to give undue importance to other
parts of the same which are only used as a convenient mode of
constructing the entire device, the difficulty attending the
investigation will be greatly diminished, if not entirely overcome.
Cahoon v. Ring, 1 Cliff. 620.
Authorities concur that the substantial equivalent of a thing,
in the sense of the patent law, is the same as the thing itself, so
that if two devices do the same work in substantially the same way
and accomplish substantially the same result, they are the same,
even though they differ in name, form, or shape. Curtis, Patents
(4th ed.), sec. 310.
Page 97 U. S. 126
Apply that principle to the case before Court and it is clear
that the knife in the respondents' machine, when considered in
connection with the striker, is substantially the same thing as the
cutter in the machine of the complainants when put in operation by
the means employed to raise it and let it fall to perform the
cutting function, without which the machine would be of no
value.
Tested by these considerations, it is clear that the decree of
the circuit court is erroneous even if the construction of the
patent is that which the respondents assume it to be, as they do
not contend that the claim for the cutter used by the complainants,
as embodied in the first claim of their patent, is invalid.
The decree will be reversed and the cause remanded with
directions to enter a decree in favor of the complainants and for
further proceedings in conformity with the opinion of this court,
and it is
So ordered.