Preliminary design problem

A client needs to test small, load-bearing, mechanical release links. The client tells you that the links will be flat, at most 4” long by 1.5” wide by 1/2” thick. There is a nominal 3” distance between the two ½” holes in the links that are used to connect to the loads. The links contain a mechanism that will cause the link to come apart and release the load when it is activated.

The client wants you to design a test fixture for these links. It needs to

  • Provide 5/8” long, ½” diameter pins that are nominally 3” apart (should be readily adjustable) to connect the links to applied loads
  • Be able to apply up to 20-lb to the link
  • Be strong enough to put significant load, up to 100-lb, on the link
  • Be able to test the links in both tension and compression
  • Be able to move as the release mechanisms are activated – not a significant amount, but enough to show that the load has been completely released
  • Be compact and efficient, but also contains enough extra room for sensors and instrumentation, which are yet to be determined
  • Be small and light enough to transport, and both clear and “elegant” enough to use for client demonstrations
  • Incorporate most, if not all, of the ideas in Elements of Mechanical Design

For Wednesday, January 21, 2015:

Prepare a brief, 2-3 page, description of a preliminary design that incorporates as many as possible of the features above. Present your design as annotated sketches and/or CAD drawings, with a description of how each of the requirements above is satisfied, or not.

Phase II

Revise your design of January 21, 2015, to include the following new specifications:

  • A total weight of not more than 5-lb (not including any external weights, if used for loading)
  • Must fit within a volume of 8” x 11” x 4” (high) or less
  • A factor of safety between 1.5 and 2.5, given a 100-lb load on the link (in either tension or compression)
  • Must be completely mechanical in function
  • Design cannot look like the designs presented by Greg Hickman or Dr. Latcha

Turn in a report on March 11, 2015 that includes:

  • A detailed design – CAD models, material specifications, FEA of critical and load-bearing components, complete bill of materials.
  • Discussion of how your new design satisfies more of the Elements of Mechanical Design (see link on syllabus) than your original design

Phase III

You have been assigned to design groups, and are to consolidate your ideas so far into a solution that will satisfy the requirements of the project, address the feedback you’ve been given individually, and meet most if not all of the guidelines discussed in class for successful mechanical design.

A formal report is due on April 20, 2014. Please turn in a hard copy to Dr. Latcha no later than 6:30 pm on Monday April 20, 2014. Use the guidelines linked to from the ME 486 syllabus to prepare your report

In addition to these guidelines, in the discussion each group member will include descriptions of his/her two previous attempts, including graphics, a brief description of how the devices function and the feedback given. These descriptions need not be more than one page for each group member.