top button
Flag Notify
    Connect to us
      Facebook Login
      Site Registration Why to Join

    Get Free Puzzle Updates

Facebook Login
Site Registration

Why in all over the world man hole top cap is round?

0 votes
33 views
Why in all over the world man hole top cap is round?
posted Jul 1, 2015 by anonymous

Share this puzzle
Facebook Share Button Twitter Share Button Google+ Share Button LinkedIn Share Button Multiple Social Share Button

1 Answer

0 votes
  1. A round manhole cover cannot fall through its circular opening, whereas a square manhole cover might fall in if it were inserted diagonally in the hole. The existence of a "lip" holding up the lid means that the underlying hole is smaller than the cover, so that other shapes might suffice.
  2. Round tubes are the strongest and most material-efficient shape against the compression of the earth around them.
  3. A round manhole cover of a given diameter has a smaller surface area than a square cover of the same width, thus less material is needed to cast the manhole cover, meaning lower cost.
  4. The bearing surfaces of manhole frames and covers are machined to assure flatness and prevent them from becoming dislodged by traffic. Round castings are much easier to machine using a lathe.
  5. Circular covers do not need to be rotated to align with the manhole.
  6. A round manhole cover can be more easily moved by being rolled.
  7. A round manhole cover can be easily locked in place with a quarter turn (as is done in countries like France), which makes them hard to open without a special tool. Lockable covers do not have to be made as heavy, because traffic passing over them cannot lift them up by suction.
answer Aug 1 by Hanifa Mammadov



Similar Puzzles
+2 votes

Ten men were in a boat on the river Ganga. The boat turns over, and all men sink to the bottom of the river, yet not a single man got wet!

WHY?

0 votes

A man from Switzerland is stuck in Germany during the World War II.

The only way to escape is to cross a bridge over a river from Germany to Switzerland.

There is a sentry beside the bridge who comes out every three minutes.

If the man goes from Germany to Switzerland, he will be shot.

If he wants to go from Switzerland to Germany, he will be taken back to Switzerland.

It takes six minutes to walks & four minutes if he runs.
How does the man escape?

0 votes

Belonging to a creature with claws curled
I can lead you to the top of the world
Of a ladle I'm part
On a mariner's chart
Prominent on a black canopy pearled

What am I?

Contact Us
+91 9880187415
sales@queryhome.net
support@queryhome.net
#280, 3rd floor, 5th Main
6th Sector, HSR Layout
Bangalore-560102
Karnataka INDIA.
QUERY HOME
...