I probably should know this... but it's been awhile since I've had to
deal with any mechanical / GD&T drafting.... got given a drawing today -
something that had ben saved out of Inventor to a DWG file (a piece of
sheet aluminum shaped into a cover panel). Two of the dimensions were
inside an "oval" (actually two half circles with connecting lines..).
It's an associative dimension - measuring the distance between two holes
and of a cutout....
My question is - what sort of dimension is this? What does the oval
represent? Looked on the web today - but couldn't find any reference to
a dimensioning standard of that sort....
(knew I shouldn't use the word 'oval'...)
This isn't really an "oval" - that is just what I called it. Imagine a
circle split down the center vertically, the two halves separated and
the ends connected together with two parallel lines.... basically its
something like the rectangular box that you put a geometric tolerance
value in - but with rounded ends... and there are no ovals on the piece
- it's a piece of flat stock that has been die cut and bent into a shell
for a electronics panel. The measurement is the distance between the
center points of two screw holes...
I've dug through a bunch of my textbooks and reference books and still
can't find what this is suppose to represent.... guess I'm going to have
to find the person that originally did the drawings in Inventor and ask....
No.. I figured it out while at work today (got on to someone's computer
that had Inventor..) - it's something called a "Inspection Dimension",
something apparently used in manufacturing. I'd never seen it used
before myself. Seems that regular AutoCAD has it too (leastwise 2008+ -
it's under the Dimension drop-down menu.
Well, now I've learned two things....
But I thought that a "lozenge" was more of a rhombus - with triangular
ends.. (which apparently is one of the styles for this Inspection
Dimension feature, but I didn't know that at the time). The dimension I
was looking at was the other style with the round ends - is that also
called a "lozenge" too?
Well I've learned something too. At school (a long, long time ago) I
was taught that the capsule shape was a lozenge but mathematics
reserves that word for a rhomboid. "Slot" (or possibly "allantoid")
seems like a better name after all. How about "cartouche", as in the
shape that encloses the pharaoh's name on the Rosetta Stone?
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