Over the years, the USPTO has used many schemes to provide a framework that
is uniform for the entire classification system as well as to provide schemes
that optimize a class’s usefulness as a search aid.
The current philosophy
on the organization of patent data was formulated in early 1964 and set
forth in the publication "Development and Use
of Patent Classification Systems" (DUPACS). This publication
was issued in January 1966 and is now out of print; however, a number of
copies still exist in each group in the Examining Corps.
DUPACS sets forth a
model (shown below) that should be used in the creation of a new classification
system; i.e., a class. However, this model is a theoretical
standard and many deviations will be found in practice. The
primary reason for these deviations is that all classes are built based
upon a thorough review of the art to be contained in the new class. The
structure of the class is dictated by the art itself. This review of the
actual documents frequently causes modification of the theoretical model.
The specific arrangement
of subclasses within a schedule will define that schedule’s hierarchy as
noted in the main portion of this handbook. The hierarchy will almost invariably
arrange the subject matter with the most complicated and comprehensive material
at the top of the schedule and the simpler material at a lower position
in the schedule.
Further, all modern
schedules exhibit exhaustive subclasses. This concept is discussed in depth
in the main body of this handbook.
With these preliminary
thoughts and reservations, a discussion about the preferred theoretical
structure of the "Modern" class will now take place.
The
"modern" class is often represented as an inverted right triangle.
As you can see in the
above scheme, the subject matter is arranged from the most complicated (the
top of the triangle) to the simplest (the bottom of the triangle).
A, AB, Ap, and X are the four characters of subject matter in the
above scheme. "A" represents the basic subject
matter of the class, e.g., in a class of pumps.
- "A"
would be the types of pumps found in the class (e.g., jet pumps, reciprocating
pumps, etc.);
- "AB"
represents the basic subject matter combined with subject matter having
a different proximate function, effect, or product; that is, the subject
matter of another class (e.g., a pump combined with and driven by a vehicle);
- "Ap"
represents the basic subject matter combined with a perfecting feature,
i.e., some structure that enhances or improves the operation of basic
subject matter device (e.g., an intercooler located between stages of
a pump which improves the overall efficiency of the pump by carrying away
unwanted heat generated during the pump’s operation);
- "X"
represents the subcombinations of the basic subject matter or elements
peculiar to or associated with the basic subject matter, when such subcombinations
or elements are not specifically provided for in some other class (e.g.,
pump casings, etc.).
In addition to subclasses
providing for the above noted material, modern schedules frequently provide
for the following additional concepts:
a.
Condition Response (Automatic Control)
b. Measuring and Testing
c. Special "A"
d. Convertible
e. Combined
f. Plural "A"
g. Miscellaneous
A brief description
of each of the above types of subclasses is given below.
Condition Response (Automatic Control)
Condition response is
a broad concept that embraces the variant, Automatic Control, within its
boundaries. Condition responsive subclasses are intended to provide a home
for devices that include a means to sense a randomly
occurring condition or change in condition that will effect a change
in the operation of a device provided for in the class. This concept embraces
devices as complicated as a milling machine with means to sense the position
of a cutting head and acts to disable the machine if any misalignment is
sensed. It also includes within its scope a device as simple as a pressure
biased check valve, wherein the under surface of the valve seat senses fluid
pressure which causes the valve to unseat when the pressure against the
underside of the seat reaches a predetermined point.
"Automatic Control"
is a more restrictive concept that includes means to sense a randomly occurring
condition or change of conditions that operates on a separate
means to effect control of an apparatus, e.g., the milling machine
mentioned above. This concept requires a sensor, e.g., a slipper or feeler
located adjacent to the system, which senses a condition or change in condition,
e.g., tool misalignment. Once this condition is sensed, the sensing means
operates on another device, e.g., a switch or valve, which controls a different
medium to regulate the operation of the controlled device. There has been
a tendency in recent years to move away from the title "Automatic Control"
and to substitute the title similar to "Control Means Responsive to Sensed
Condition."
Another concept closely
allied to Automatic Control is Programmed or
Cyclic Control. These devices frequently include sensors;
however, the device employing the sensors merely performs repetitive operations.
There is a basic "law of the machine" and the sensors are actuated in sequence
to control the operation of the device based on that law. In other words,
the condition sensed is predictable rather than random.
Also embraced by this
concept are those devices that employ stored intelligence (e.g., magnetic
tape) to control the operation of the machine in a prescribed, repetitive
fashion.
These subclasses are
generally grouped in the same area of the schedule and this area is generally
located relatively high in the schedule.
Measuring
and Testing
Many classes provide for their basic subject matter combined with some type
of measuring or testing device. This represents a special type of "AB"
combined subclass, but is no different in character than any other "AB"
type subclass. In fact, its only distinction is its frequent occurrence.
Combined subclasses
drawn to a class’s basic subject matter combined with heating or cooling
means or lubricating means are also frequently found in many modern classes.
Special
"A"
It frequently happens that special collections of unique basic subject matter
are provided for very high in the class schedule. These collections are
of special search value and could get lost if they were positioned lower
in the schedule. This collection will also appear above the "Combined"
subclass even though they are not very complicated and are not drawn to
combinations or basic subject matter plus perfecting feature. An example
of one such collection is drawn to getter type pumps in Class 417.
Convertible
This subclass provides for devices which, while they are the basic subject
matter of one class, are intended to be changed into the basic subject matter
of another class by a rearrangement of their parts. This concept also provides
for the change of one type of device provided for in a given class into
a different type of device also provided for in the same class by rearrangement
of the parts of the device.
Combined
As previously noted
in this handbook, "Combined" represents a dividing
point in the schedule. Unless a note to the contrary appears, the subclass
is exhaustive of all combinations, i.e., "AB"
type and "Ap" type subclasses not provided
for higher in the schedule.
Generally, all subclasses
appearing below "Combined" will be drawn to
either the basic subject matter of the class or to the subcombination and
elements peculiar to or associated with that subject matter.
Therefore, a "Combined"
subclass, in practice, is a "Miscellaneous" subclass for combinations not
provided for elsewhere.
Plural
"A"
Another type of collection that frequently appears in a modern schedule
is one drawn to systems employing multiple devices provided for in the class.
The multiple devices may be of the same type or they may be different types,
e.g., two diaphragm pumps connected in series or a diaphragm pump and a
reciprocating piston type arranged in the same fashion.
This subclass is usually
positioned immediately below the "Combined"
subclass.
Miscellaneous
In many modern schedules,
the last subclass contained in the schedule is "Miscellaneous."
This subclass is defined
in extremely broad terms and is intended to be exhaustive of all subject
matter admitted to the class but not provided for higher in the class. Each "Main
Line" subclass is exhaustive for the material provided for in that
main line; however, there will often be a residue of material that does
not fit the existing "Main Lines." If a "Combined" subclass exists in the
schedule, only unprovided for basic subject matter and unprovided for subcombinations
and elements will be found in "Miscellaneous." It must be remembered that
"Combined" is exhaustive of combinations of the basic subject matter and
the subject matter of some other class.
In conclusion, the above
model is a theoretical model, and many deviations will be found in practice,
e.g., Classes 198 and 251 contain no "Combined" subclass even though they
are modern classes. This omission was a conscious act of the Classifier
involved and was dictated by the nature of the art embraced by the class.
One must always carefully
review a schedule while using it to look for exceptions from this model.
Index
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