×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Force of a 3-6 Ton Trailer on a hook to a bus?

Force of a 3-6 Ton Trailer on a hook to a bus?

Force of a 3-6 Ton Trailer on a hook to a bus?

(OP)
Hello everyone

I am working out the apropiate size of the end transverse beam in a coach/bus which has a 3 to6 Ton trail tied to a hook in that beam. Does anybody know the appropiate horizontal/vertical force magnitude that I should take into account for my calculations? I consider braking (1 g) as the maximum effort. Is that right or do I miss some other extreme situation?

Thank you everybody

PedroRB

RE: Force of a 3-6 Ton Trailer on a hook to a bus?

In the absence of any better info chassis parts are often designed to 3g vertical inputs, 2g longitudinal, and 1 g lateral, to the wheels. Determining how these loads relate to the tow ball is a task for the designer!

Cheers

Greg Locock

RE: Force of a 3-6 Ton Trailer on a hook to a bus?

Hi,
The following equations are from SAE standard J684, regarding testing of the receiver tube, which ties into your beam.

1.  V = .47R + 480
    L = .47R + 480
2.  L = -(.23R + 1530)
    V = .15R
3.  L = .23R + 1530
    V = .15R
4.  T = .20R + 500

Where V is the vertical force, positive in the downward direction; L is the horizontal force, positive in the forward direction towards the cab; T is the transverse force; R is the hitch rating, in your case 12,000#.  
Remember, these are the loads at the the ball.  You will get a moment from the vertical force multiplied by the distance from the ball to the beam.
Good luck,
hauptmann


RE: Force of a 3-6 Ton Trailer on a hook to a bus?

(OP)
Thank you all.

Just a pair of questions, Hauptmann, about the equations: are the forces expressed in Pounds or Newtons? What´s the hitch ratio? Is the SAE Standard J684 available in internet for free?

PedroRB

RE: Force of a 3-6 Ton Trailer on a hook to a bus?

PedroRB,
All the forces are in pounds.  The hitch will be rated at a weight representing the maximum allowable towable weight,  12,000 lb for your case.  I do not know of any site with this standard available.  We have the three volume set of SAE standards which covers just about everything you might have questions about.  You can buy it online at sae.org for about $50.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources