old invention. An inventor is entitled to all the capacities of his
invention.


COMBINATION CLAIMS.

Many people have an erroneous notion regarding patent claims, and
consider the expression "combination" as an element of weakness. The
fact is, that all mechanical claims that are good for anything are
combination claims. No claim for an individual mechanical element has
come under my notice for many years and I doubt if a new mechanical
element has been lately invented. All claims resolve themselves into
combinations, whether so expressed or not. Combination does not
necessarily imply separateness of elements. The improved carpet tack
is after all but a peculiar combination of body and head and barbs.
The erroneous public contempt for combination claims is based upon the
legal maxim, that if you break the combination you avoid the claim and
escape infringement, and this legal maxim should be well understood in
formulating the claims. If the claim calls for five elements and the
competitor can omit one of the elements, he escapes infringement.
Therefore, the claim is good only when it recites no elements which
are not essential.

Many inventors labor under the delusion that a claim is strong in
proportion to the extent of its array of elements. The exact opposite
is the truth, and that claim is the strongest which recites the
fewest number of elements. It is the duty of the inventor to analyze
his invention and know what is and what is not essential to its
realization. It is the duty of the patent solicitor to sift out the
essential from the non-essential, and to draft claims covering broad