HOME  |  NEWS  |  BLOGS  |  MESSAGES  |  FEATURES  |  VIDEOS  |  WEBINARS  |  INDUSTRIES  |  FOCUS ON FUNDAMENTALS
  |  REGISTER  |  LOGIN  |  HELP
<<  <  Page 2/3  >  >>
Tool_maker
User Rank
Platinum
Re: A really practical gadget
Tool_maker   1/3/2013 1:02:46 PM
NO RATINGS
  I am with you Myron. In my years in the shop I straightened dozens of shafts, just as you describe. You put a block under the shaft/plate or whatever, at each end of the distortion, bent side up, and then apply pressure until it overbends. Measure with a straight edge and dial indicator, aplly that lesson and try again If there is a formula for how much over bend is required I have never seen it. This is also a problem I run into quite often in pressforming shallow bends. It may take many tries before you get to the right point of elastic deformation and it stays where you want it to be. 

  This device would have to be recalibrated everytime one of the points of contact has been changed. I can see where it would be usefull on a repetative operation (same shaft/same offset), but for just general arbor press bending, I think it would be a toy that would end up in a corner somewhere while work was being done.

MYRONB
User Rank
Gold
Re: A really practical gadget
MYRONB   12/28/2012 12:41:39 PM
NO RATINGS
If the only object is to straighten a piece of metal, then shouldn't we just apply enough force to "overbend" the workpiece to allow for springback and then measure the piece for straightness?   Then, if necessary, hit the piece again and re-measure as necessary.  It seems we just need a press with sufficient force to bend the metal. 

I had the damaged journals of of a race-engine crankshaft welded and the rebuild shop did just as I described above to straighten the shaft before machining and grinding the journals.  The press operation  was done by "eyeball",and precision measurements were made  with a dial indicator to check concentricity.  That crank lasted several seasons with many sprints up to 9.000 rpm with no problems.    Unless there is more to this story, I'm not sure why a force gauge is required.

Best regards,  Myron Boyajian

enauman
User Rank
Iron
Re: What am I missing?
enauman   12/23/2012 2:28:06 AM
NO RATINGS
The comment about the number of pumps on the handle was editorial and has nothing to do with the calibration or operation of this system.  I was trying to relate how one goes about straightening something on a press that has no force indication or pressure gage.  In which case, the only way to crudely estimate the force applied between successive 'trys' is to count the pulls on the handle.

enauman
User Rank
Iron
Re: who made the front panel?
enauman   12/22/2012 9:34:06 PM
NO RATINGS
I made the front panel.  I used BobArt (from BobCAD) to generate the engraving artwork.  I have a 10x54 3 axis CNC vertical mill in my garage that I used to cut the panel and engrave it.  I also use the mill to make my own Printed Circuit Bords.

RichardBradleySmith
User Rank
Bronze
More: Hydraulics in the AC72s.
RichardBradleySmith   12/21/2012 2:50:51 PM
NO RATINGS
In case you missed it: "We have 38 hydraulic cylinders. We want to avoid running hydraulic piping to each of them, because that would be heavy, so we have electrovalves embedded in the wing to actuate the hydraulics. But if you had two wires, positive and negative, running to each electrovalve, your wing would look like a PG&E substation, and that's heavy too, so we use a CAN-bus [controlled area network] with far fewer wires. Still, it's incredibly complex.

"We wind up with lot of hydraulics," Cayard says, "and the America's Cup rules don't allow stored power, so two of our eleven guys—we think, two—will be grinding a primary winch all the race long.  Not to trim, but to maintain pressure in the hydraulic tank so that any time someone wants to open a hydraulic valve to trim the wing, there will be pressure to make that happen."

Full story:  http://blueplanettimes.com/?p=8022

bob from maine
User Rank
Platinum
Re: A really practical gadget
bob from maine   12/21/2012 2:37:52 PM
NO RATINGS
The one I built has a pressure gauge like the one shown. The pressure on the gauge directly correlates to the pressure applied to the component being bent/mangled/distressed. The gauge displays psig which can be fairly easily converted to lbs of force. If I was developing a process and had to train someone else to use this device, I think this display would be much more useful. Good idea.

Tom-R
User Rank
Gold
Re: A really practical gadget
Tom-R   12/21/2012 12:54:57 PM
NO RATINGS
I needed a set of jacks made with pressure gauges like this once. We used them to check the compression force of springs on packaging equipment in several plants. We planned on calibrating them so we knew the force/PSI reading, and then using a table. But a little work by our supplier let us select a hydraulic jack that had a cylinder area close enough to 1" that we could just take the gauge reading in PSI and read it as lbs force. We confirmed it with a force gauge in the shop, and it was bang on.

RandD
User Rank
Iron
Re: A really practical gadget
RandD   12/21/2012 10:30:45 AM
NO RATINGS
In the "old days" a pressure gauge was used, located similarly to the pressure transmitter in this application. On some rams, the gauges were calibrated in lbs (or Tons), rather than psig, or sometimes both. I don't recall ever seeing one with a settable pointer, but that would be an obvious useful feature.

2WheelFlyer
User Rank
Iron
Re: I could really use that
2WheelFlyer   12/21/2012 10:28:52 AM
NO RATINGS
This intriques me. I have a process that could use it with the addition of an adjustable delay at max pressure followed by an output to a hydraulic solinoid to return the ram home.

Thanks for engaging your brain and sharing!

Blue skies.

Please contact me - falconridgeinc@comcast.net

Droid
User Rank
Platinum
What am I missing?
Droid   12/21/2012 9:51:32 AM
NO RATINGS
This is cool.  I built my own 50-ton shop press using old fork-lift rails and would love to have this gadget.

However - Seems like there's some confusion here over relatively simple concepts.  Such as equating the number of pumps on the handle to force? Doesn't the number of pumps equate to the volume of oil going into the ram which would equate to distance of ram travel?  I would have simply gone to Excel; created a nice laminated graph correlating pressure to force and taped it to the press.  

Adding a device to precisely measure the travel distance of the ram could be useful.

<<  <  Page 2/3  >  >>


Partner Zone
Latest Analysis
Dean Kamen tells an audience at MD&M East 2014 how his team created the DEKA Arm to meet DARPA's challenge to design a better prosthetic arm for wounded veterans.
The new draw-it-on-a-napkin is the CAD program. As CAD programs become more ubiquitous and easier to use, they have replaced 2D sketching for early concepting.
These free camps are designed for children ages 10 to 18. Attendees are introduced to 3D CAD software and shown how 3D printers can make their work a reality. Here we check out the stops in California and Utah.
A University of Chicago graduate has invented a compact elliptical trainer that lets people work out at their desk while they work.
Dean Kamen told an audience at MD&M East 2014 that FDA regulators aren't to blame for stalling innovation in the medical device industry. Hear what he had to say.
More:Blogs|News
Design News Webinar Series
7/23/2014 11:00 a.m. California / 2:00 p.m. New York
7/17/2014 11:00 a.m. California / 2:00 p.m. New York
6/25/2014 11:00 a.m. California / 2:00 p.m. New York
5/13/2014 10:00 a.m. California / 1:00 p.m. New York / 6:00 p.m. London
Quick Poll
The Continuing Education Center offers engineers an entirely new way to get the education they need to formulate next-generation solutions.
Aug 4 - 8, Introduction to Linux Device Drivers
SEMESTERS: 1  |  2  |  3  |  4  |  5  |  6


Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.
Next Class: August 12 - 14
Sponsored by igus
Learn More   |   Login   |   Archived Classes
Twitter Feed
Design News Twitter Feed
Like Us on Facebook

Sponsored Content

Technology Marketplace

Copyright © 2014 UBM Canon, A UBM company, All rights reserved. Privacy Policy | Terms of Service