Patent It Yourself - PDF Archive

262 | Patent it YOURSELF
Summary of PTO Drawing Rules (continued)
14. Shading: Objects can be shaded with surface and edge
shadings so that the light appears to come from the
upper left at a 45-degree angle. Thus the shade sides
of all objects (the right and bottom) should be done
with heavier lines. Surface shading should be open.
On perspective views, the closest edges should be
made heavier. Edge and surface shading is mandatory
in design patent applications, and optional in utility
patents.
15. Scale: The scale should be large enough to show the
mechanism without crowding when the drawing
is reduced to two-thirds of its original size for
reproduction. Detailed parts should be shown on a
larger scale, and spread out over two or more sheets if
necessary, to accomplish this, but the number of sheets
should not be more than necessary.
16. Figures: The different views should be consecutively
numbered figures, for example, “Fig. 1A,” “Fig. 1B,” “Fig.
2,” etc. Each figure should be separate and unconnected
with any other figure. If possible, you should number
the figures consecutively on consecutive sheets.
However, if you want to arrange the figures in nonconsecutive
order to use space efficiently, that’s okay,
albeit less desirable.
17. Reference Numerals and Lead Lines: Numbers must
be plain, legible, carefully formed, and not encircled.
They should be at least 3.2 mm ( 1 /8") high. When parts
are complex, they should not be placed so close that
comprehension suffers. They should not cross or mingle
with other lines. When grouped around a part, they
should be placed around the part and connected by
lead lines to the elements to which they refer. They
should not be placed on hatched or shaded surfaces
unless absolutely necessary; if then, they should be
placed in a blank space in the hatching or shading.
(Numerals are preferred to letters.) Arrowheads should
not be used on lead lines, but if a numeral refers to an
entire assembly or group of connected elements, its
lead line can have an arrowhead, or it can be underlined
to distinguish it from the lead lines of numerals that
refer to a single part.
18. No Duplication of Reference Numerals: The same part
in different figures must always be designated by the
same reference numeral. Conversely, the same reference
numeral must never be used to designate different
parts. Numbers with primes and letter suffixes are
considered different numbers.
19. Graphic Symbols: These can be used for conventional
parts, but must be defined in the specification. For
instance, if you use an encircled “M” for a motor,
the specification should say, for example, “A motor,
represented in Fig. 2 by an encircled ‘M.’” Conventional
symbols, such as those approved by the IEEE, ASA, etc.,
or from any standards or symbols book, can be used.
Arrows should be used to show direction of movement,
where necessary.
20. Descriptive Matter: The rules state that descriptive
matter on the drawings is not permitted. I vehemently
oppose this rule, since the use of descriptive matter on
drawings makes them far more meaningful, and since
textbooks, magazine articles, etc., all use drawings with
ample descriptive matter. Unfortunately, this rule is
being enforced now, so just put the figure number and
nothing else under each figure—for example, “Fig. 1,”
and not “Fig. 1—Apparatus in Ready State.”
The Rules do permit (and even require) legends to be
used within rectangular boxes, on flowcharts, piping
(plumbing) lines, or wherever else additional clarity is
highly desirable. If used, the descriptive matter lettering
should be as large as, or larger than, the reference
numerals.
21. Views: The drawings should have as many views
(figures) as are necessary to show the invention. The
views may be plan, sectional, exploded, elevational,
or perspective; detailed larger-scale views of specific
elements should be employed. Engineering views (such
as front, side, bottom, or back) should not normally be
used if perspective views can adequately illustrate the
invention. If exploded views are used, the separated
parts of the same figure must be joined by assembly
lines or embraced by a bracket. (See Fig. 8D.)
A large machine or schematic or flowchart can be
extended over several sheets, but the views should
be arranged to be easily understandable and so that
the sheets can be assembled adjacent each other to
show the entire machine. Never place one figure within
another unless the view is the only one on the sheet.
22. Sectional and Enlarged Views: The plane upon which
a sectional view is taken should be illustrated in the
general view by a broken line, the ends of which should
be designated by numerals corresponding to the figure
number of the sectional view with arrows indicating
the direction in which the sectional view is taken. For
example, suppose your Fig. 1 shows a left-side front