Below are the guidelines which if obeyed, the patent drawings will be acceptable to all (USPTO, EPO, PCT etc.).
Colour of Drawings
Black and white drawings are normally required. But coloured drawings are permitted in specific cases with prior permission.
Sheet Size
The size of the sheets for drawings must be A4 (21.0 cm by 29.7 cm) or Letter Paper (21.6 cm. by 27.9) cm
Margins
The following margins should be left blank (with no borderlines):
- Top: 25mm
- Left Side: 25 mm
- Right Side: 15mm
- Bottom: 10 mm
Views
The drawing must contain as many views as necessary to show the invention in entirety. They may be the following:
- Front View/ Elevation
- Rear View
- Right Side View
- Left Side View
- Top View/ Plan
- Bottom View
- Perspective View
- Isometric View
- Detailed View/ Enlarged View
- Partial View
- Sectional View
- Partial Sectional View
- Exploded View
- Assembled View
Note:
- Views should not have the center lines
- In an EXPLODED VIEW, the separated parts should be embraced by a bracket
- PARTIAL VIEWS drawn on separate sheets must always be capable of being linked edge to edge so that no partial view contains parts of another partial view. A smaller-scale view should be included showing the whole view formed by the partial views and indicating the positions of the parts shown.
- The plane upon which a SECTIONAL VIEW is taken should be indicated on the view from which the section is cut by a broken line. The ends of the broken line should be designated by Arabic or Roman numerals corresponding to the view number of the sectional view and should have arrows to indicate the direction of sight. Hatching must be used to indicate section portions of an object. Hatching should not impede the clear reading of the reference characters and lead lines. If it is not possible to place reference characters outside the hatched area, the hatching may be broken off wherever reference characters are inserted.
- An ALTERNATE POSITION may be shown by a broken line superimposed upon a suitable view if this can be done without crowding; otherwise, a separate view must be used for this purpose.
Graphic Forms in Drawings
- Chemical or mathematical formulas, tables, computer program listings, and waveforms may be submitted as drawings. They are subject to the same requirements as drawings.
- Each chemical or mathematical formula must be labelled as a separate figure, using brackets when necessary
- Each group of waveforms must be presented as a single figure, using a common vertical axis with time extending along the horizontal axis.
- Each individual waveform discussed in the specification must be identified with a separate letter designation adjacent to the vertical axis.
Arrangement of Views
- All views on the same sheet should stand in the same direction and, if possible, stand so that they can be read with the sheet held in an upright position (i.e. the Portrait orientation).
- If views wider than the width of the sheet are necessary for the clearest illustration, the Landscape orientation may be used such that the top of the sheet is on the right hand side and the margins are left unchanged.
Front Page View
One of the views should be suitable for inclusion on the front page of the patent application publication.
Scale
The scale of the drawing must not be shown and should be sufficient enough so that the details are not crowded even after the reduction in size to its two thirds.
Character of Lines, Letters & Numbers
Every line, number, and letter must be durable, clean, black, sufficiently dense and dark, and uniformly thick and well-defined. The weight of all lines and letters must be heavy enough to permit adequate reproduction. Lines and strokes of different thicknesses may be used in the same drawing where different thicknesses have a different meaning.
Shading
The use of shading in views is encouraged if it aids in understanding the invention and if it does not reduce legibility. Shading is used to indicate the surface or shape of spherical, cylindrical, and conical elements of an object.
Legends
Suitable descriptive legends may be used. They should contain as few words as possible.
Numbers, Letters & Reference Characters
- Numerals are preferred for reference characters.
- They must not be used in association with brackets or inverted commas, or encircled
- They must be oriented in the same direction as the view.
- Numbers, letters, and reference characters must measure at least 0.32 cm in height
- They should not cross or intersect with the lines.
- They should not be placed upon hatched or shaded surfaces. When necessary, such as indicating a surface or cross section, a reference character may be underlined and a blank space may be left in the hatching or shading where the character occurs so that it appears distinct.
Lead Lines
- These lines may be straight or curved and should be as short as possible.
- They must originate in the immediate proximity of the reference character and extend to the feature indicated.
- Lead lines must not cross each other.
- Lead lines are required for each reference character except for those which indicate the surface or cross section on which they are placed. Such a reference character must be underlined to make it clear that a lead line has not been left out by mistake.
Arrows
Arrows may be used at the ends of lines, provided that their meaning is clear, as follows:
- on a lead line, a freestanding arrow to indicate the entire section toward which it points;
- on a lead line, an arrow touching a line to indicate the surface shown by the line looking along the direction of the arrow; or
- to show the direction of movement
Numbering of Sheets of Drawings
- The sheets of drawings should be numbered in Arabic Numerals.
- These numbers, if present, must be placed in the middle of the top of the sheet, but not in the margin.
- The numbers can be placed on the right-hand side if the drawing extends too close to the middle of the top margin.
- The numbering should be larger than the numbers used as reference characters to avoid confusion.
- confusion. The number of each sheet should be shown by two Arabic numerals placed on either side of an oblique line, with the first being the sheet number and the second being the total number of sheets of drawings
