In view of the previous state of the art, the claims in the
patent granted to Charles B. Bristol, May 16, 1865, for an
improvement in harness hooks or snaps must be restricted to the
precise form and arrangement of parts described in the
specification and to the purpose therein indicated.
Bill in equity to restrain alleged infringements of letters
patent. Decree for complainants. Respondents appealed. The case is
stated in the opinion of the Court. The following are the figures
referred to in the opinion.
image:a
Page 121 U. S. 479
image:b
MR. JUSTICE BRADLEY delivered the opinion of the Court.
This is a suit on a patent granted to Charles B. Bristol, May
16, 1865, for an improvement in harness hooks or snaps, the
complainants being assignees of the patent. These hooks are usually
attached to the end of a strap or chain for the purpose of
fastening it to a ring or staple, as in the case of a tie-strap for
fastening a horse to a post. The small hook by which a watch chain
is fastened to the ring or stem of the watch is an example. It has
a movable part called the tongue, which is connected to the shank
of the hook by a pivot, and is kept in place against the end of the
hook by the pressure of a spring acting between the shank and the
tongue. The tongue may be pressed inward, so as to admit the ring
or staple, and is thrust back to its place by the action of the
spring. In some form or other, the implement has long been in use.
The patent in question relates to the mode of arranging the spring
in the tongue and of attaching both to the shank of the hook. The
complainants' expert says:
"The invention shown and described in the patent of Bristol is
an improvement in that class of snap hooks in which the tongue is
pivoted in a recess between two cheeks in the shank. In this
recess, a coil spring is arranged around the pivot so that the two
ends of the spring bear one upon the tongue and the other upon the
body of the hook, tending to press the tongue up against the end of
the hook, but yet permit the tongue to be depressed to open the
Page 121 U. S. 480
hook. In this class of hooks prior to Bristol, the tongue was
cast with a recess upon its under side to form two cheeks
corresponding to the cheeks in the shank of the hook. The cheeks on
the tongue were drilled corresponding to the hole through the
cheeks in the shank, so that a rivet could be inserted through the
sides of the shank and both sides of the tongue to form the pivot
on which the tongue would turn. The coil of the spring was arranged
around the pivot, the two ends bearing one upon the shank and one
upon the hook, as before described."
The principle of this arrangement was exhibited in many
different forms. Sometimes the spring merely passed around the
pivot without any coil; sometimes a straight spring was so secured
to the one part, and made to press against the other, as to effect
the same object. One would hardly suppose that a patentable
invention could have been made in relation to this little device.
But many patents have been and probably more will be granted. The
Bristol patent now sued on is one of the latest in the series which
has been brought to our attention.
The particular contrivance which is claimed as an invention in
this patent may be described as follows: instead of having a
separate pivot or pin, to pass through the cheeks or ears of the
hook and tongue for the purpose of connecting them together and
holding the coil of the spring, a small projection or fulcrum, to
answer the purpose of a pivot, is cast as a part of one of the
cheeks of the hook, on its inner side, and the cheeks (being made
of malleable cast-iron) are spread further apart, and the recess
between them is thus wider than they are intended to be when the
article is finished. The coil of the spring is placed on the
projecting fulcrum. The tongue is made with a recess as usual, but
one side of this recess is left open, the other side having the
ordinary cheek perforated with a hole to admit the fulcrum pivot.
The tongue, thus constructed, is placed in the recess of the hook
and slipped over the spring and pivot, and then, by means of a vice
or press, the outside cheeks of the hook are squeezed together
until the fulcrum pivot passes through the hole in the cheek of
the
Page 121 U. S. 481
tongue, and comes in contact with the opposite cheek of the
hook. The patentee, after having described the construction of the
several parts, explains the mode of putting them together as
follows:
"Having made the parts as before described, I place the spiral
spring, Fig. 4, on the projection or pin
n, Fig. 2, and
slip the tongue, Fig. 3, onto the projection or fulcrum pin
n so that the spring, Fig. 4, will rest in and be enclosed
by the recess
r with the two tangential parts
h
and
i pointing towards the hook
a. I then place
the article in a proper vice or press, and close up the cavity
between
c and
d until the pin
n comes in
contact with the side or ear
c, Fig. 2, when the whole
will appear as represented in Fig. 1 (except the strap A), and will
be ready for use or sale."
The claim of the patent is as follows, namely:
"What I claim as my invention, and desire to secure by letters
patent is --"
"1. The combination of the tongue
g with the spiral
spring, Fig. 4, when the spring works on the torsion principle, and
rests in a recess (as
r) in the rear end of the tongue,
substantially as herein described."
"2. The combination of the fulcrum pin
n with the
tongue
g when the pin
g is cast in one of the
ears, and the recess or cavity is fitted to be closed,
substantially as herein described."
Only the first claim is relied on in the present suit, as the
defendants do not use the fulcrum pivot, cast with the cheek of the
hook, but the ordinary pivot, inserted in holes in both cheeks.
The defense is threefold, namely: 1st. That the supposed
invention was described in previous patents. 2d. That in view of
the state of the art, the device claimed as new was not a
patentable invention. 3d. That upon a proper construction of the
patent, the defendants do not infringe it.
Several prior patents were given in evidence which show, if not
an entire anticipation of, at least a very near approach to, the
invention claimed.
In 1852, a patent was issued to Palmer & Simmons for an
approved hook for whiffletrees, embodying the same principle
Page 121 U. S. 482
as the snap hook, in which the recess of the tongue, enclosing
the spiral spring, having precisely the same object as the recess
of the tongue and spring in Bristol's and other snap hooks, had but
one cheek, the other side of the recess being open until it was
applied to the end of the whiffletree supporting the hook, by which
it was closed up when the parts were brought together. The
connection of the two was made by a pivot passing entirely through
the cheek of the tongue and the coil spring enclosed therein, and
into the end of the whiffletree. This pivot had a broad head, which
compressed the tongue and kept it in place in the same manner as is
done by the cheek of the hook in Bristol's snap hook.
In 1859 one Daniel H. Hull patented a trace fastener which
contained a similar device so far as the arrangement of the tongue
and spring are concerned. The tongue, called in the patent the
latch, had a recess containing the spring, which was open on the
inside, opposite to a slight recess in the slotted fastener, which
corresponded to the hook in the snap hook. The pivot on which the
tongue moved, and which passed through the spiral spring, was of
the usual kind, and not cast as part of the fastener or of the
latch.
In January, 1864, a patent was granted to one C. S. Abeel for an
improvement in safety hooks in which he dispensed with both the
ears of the tongue by the use of one or two straight springs, one
end of which was inserted in a slight groove in the recess or
chamber of the hook and the other resting against the tongue either
in a groove or against a projection or shoulder.
In December of the same year, a patent was granted to Oliver S.
Judd for an improvement in snap hooks in which the spring was
arranged in the recess of the tongue, and operated exactly like the
spring in Bristol's hook, the only difference between the two being
that in Judd's hook the pivot passed through both the hook and the
tongue, and the latter had two cheeks, one on each side of its
recess. The arrangement of the spiral spring, with both tangential
ends projecting forward toward the hook, was precisely like
Bristol's.
Page 121 U. S. 483
These prior patents exhibit every feature of the Bristol snap
hook, described in the patent sued on, except the single one of the
fulcrum pivot cast as part of the cheek of the hook, and not
passing through holes in both ears. This fulcrum is the only
novelty shown in the patent, and this is not used by the
defendants. The snap hook made by them has the same pivot which is
used in Judd's hook, inserted in the same way, and passing through
both cheeks of the hook. The only particular in which it differs
from Judd's is that the tongue has but one cheek, and only one end
of the coiled spring projects forward, toward the hook, resting
against the tongue, while the other end projects backward, and
presses against the side of the recess in the tongue, which is
curved around and prolonged sufficiently for this purpose. It
differs in two respects from the Bristol snap hook, to-wit, in not
using the fixed fulcrum cast as part of the cheek and in not having
both tangential ends of the spring projecting forward toward the
hooks, but having one of the ends projecting backwards, and
pressing not against the tongue itself, but against the opposite
side of its recess, prolonged sufficiently for the purpose.
It is obvious from the foregoing review of prior patents that
the invention of Bristol, if his snap hook contains a patentable
invention, is but one in a series of improvements all having the
same general object and purpose, and that in construing the claims
of his patent, they must be restricted to the precise form and
arrangement of parts described in his specification, and to the
purpose indicated therein. As we have seen, with one exception (the
solid pivot), all the parts are old, and have been used in
combination in other things of the same general character. The use
of a recess in the tongue with one of its ears or cheeks removed
was to adapt it to the new element referred to, namely, the solid
pivot, and although the first claim of the patent is for the tongue
thus constructed, in combination with the spiral spring, as
arranged in connection with it, yet this claim must be construed in
reference to the purpose for which the tongue and spring thus
arranged were intended -- namely for adjustment upon the solid
pivot. Without this relative purpose, the combination
Page 121 U. S. 484
of the tongue and spring, by itself, would be anticipated by the
patent of Palmer and Simmons and that of Hull. If it has any
novelty, it consists in its new application to the snap hook as
devised by Bristol, and this was a snap hook provided with the
peculiar solid pivot or fulcrum pin, which is the subject of his
second claim, and to which, as we have seen, the form and
arrangement of the tongue and spring were specially adapted, and
requisite to its beneficial use. This necessary restriction of the
first claim renders it clear that it is not infringed by the
defendants, for, as before stated, they do not use the solid pivot,
but the old and long used pin, passing through both ears or cheeks
of the tongue and the hook. The defendants also use a different
device from that described by Bristol, in the arrangement of the
spiral spring, the two ends of which, instead of pointing toward
the hook, point in different directions -- one toward the hook, and
pressing against the body of it, and the other in the opposite
direction, and pressing against the side of the recess in the
tongue, which is prolonged and curved around for that purpose.
On the whole view of the case, we are satisfied that the
defendants do not infringe the patent sued on, when construed as it
must be to give it any validity.
The decision of the circuit court must therefore be
reversed, and the case remanded, with instructions to dismiss the
bill.