Drafting system and apparatus

In a drafting system for drawing perspective views and the like, the combination comprising:

• a drawing board surface having a drawing sheet superposed thereon, a horizon line and a vanishing point on the horizon line;
• a pivot pin secured upright at the first vanishing point;
• a thin, flat, elongated ruling blade body having a pair of oppositely disposed flat sides, a pair of oppositely disposed parallel ruling edges extending along the body and a pair of oppositely disposed end edges at the ends of said body, a center groove in at least one of said sides, and a removable reference head detachably mounted on said blade body, said reference head having a top portion and a pair of depending side portions forming a channel sized to receive said body, the side portions having inside guide faces for guiding movement of said reference head along said ruling edges of the blade body, one of said side portions extending laterally beyond one of said ruling edges and having at least one pin-receiving hole arranged to position said blade body on a drawing board surface, said reference head having locking means releasably locking said head to said body including a shaft having an eccentric cam disposed within said center groove, said cam being positioned to move against either of a pair of inside faces forming the sides of said center groove to wedge a ruling edge against the adjacent guide faces of said reference head.

In a drafting system for drawing perspective views and the like, the combination comprising:

• a drawing board surface having a drawing sheet superposed thereon, a horizon line, a first and second vanishing point on the horizon line;
• a first pivot pin secured upright at the first vanishing point;
• a second pivot pin secured upright at the second vanishing point;
• a first ruling blade having a thin, flat, elongated body with a pair of oppositely disposed flat sides, a pair of oppositely disposed parallel ruling edges extending along the body and a pair of oppositely disposed end edges, a center groove in at least one of said sides;
• a removable reference head detachably mounted on said blade body, said reference head having a top portion and a pair of depending side portions forming a channel sized to receive said body, the side portions having inside guide faces for guiding movement of said reference head along said ruling edges of said blade body, one of said side portions extending laterally beyond one of said ruling edges and having at least one pin-receiving hole in line with said one ruling edge whereby said first ruling blade is edge-pivoted about one of said first and second vanishing points for drawing a perspective line up to one of said vanishing points;
• and
• a second ruling blade having a laterally projecting head portion with a pin-receiving slot in line with a ruling edge receiving said second pivot pin at the other of said first and second vanishing points.

In a drafting system for drawing perspective views and the like, the combination comprising:

• a drawing board surface having a drawing sheet superposed thereon, a horizon line, a first and second vanishing point on the horizon line;
• a first pivot pin secured upright at the first vanishing point;
• a second pivot pin secured upright at the second vanishing point;
• a ruling blade having a pair of oppositely disposed flat sides, a pair of oppositely disposed parallel ruling edges extending along the body and a pair of oppositely disposed end edges, a center groove in at least one of said sides providing a pair of inside wall surfaces;
• a pair of removable reference heads, each reference head shaped in the form of a T-square head releasably attached at opposite positions on the ruling blade, each of said T-square heads having a locking cam selectively engageable with one of the inside wall surfaces of the blade and each having a plurality of pin-receiving holes at spaced intervals therealong, one of the pin-receiving holes of one of said T-square heads receiving the first pivot pin and one of the pin-receiving holes of said other T-square head receiving the second pivot pin to support the blade in a horizontal position parallel to the horizon line for use in drawing horizontal and vertical lines referenced to said vanishing points.