U-bolts

FIRST General Forum
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Posted by Patrick Dingle at 1/27/2001 1:26 AM EST

Other on team #639, Red B^2, from Ithaca High School and Cornell University.

There was some brief discussion on the General Forum about using U-clamps/bolts to mount the drill motors to the robot. Let’s say, hypothetically, that our team is using the drill motors, and hypothetically, we are considering clamping them on with large U-bolts. Does anyone have any wisdom about mounting motors with U-bolts? Or is it a bad idea in general?

Thanks
Patrick Dingle
Team 639 - Ithaca High School & Cornell University
[email protected]

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Posted by Glenn M. Krcek at 1/27/2001 4:37 AM EST

Other on team #226, Manhatan Project, from Troy and Athens High and GM CRW.

In Reply to: U-bolts
Posted by Patrick Dingle on 1/27/2001 1:26 AM EST:

: There was some brief discussion on the General Forum about using U-clamps/bolts to mount the drill motors to the robot. Let’s say, hypothetically, that our team is using the drill motors, and hypothetically, we are considering clamping them on with large U-bolts. Does anyone have any wisdom about mounting motors with U-bolts? Or is it a bad idea in general?

We mounted our drill motors using 3 U-bolts last year and it worked just fine. A couple recomendations:

  1. The Robot drive shaft should be supported on it’s own bearings so the drill motor brgs have no side loads.
  2. Let the drill motor find its own centerline (alignment to the drive shaft).
  3. Nest the motor there after it is secured to the drive shaft.
  4. The motor should be secured with the U-bolts but not overtightened.

The finalists are not the real winners of FIRST, it’s all the participants that are the real winners.

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Posted by Ken Wilson at 1/27/2001 4:50 AM EST

Engineer on team #248, FEMEX, from Philadelphia Girls High and PECO Energy Company.

In Reply to: U-bolts
Posted by Patrick Dingle on 1/27/2001 1:26 AM EST:

: There was some brief discussion on the General Forum about using U-clamps/bolts to mount the drill motors to the robot. Let’s say, hypothetically, that our team is using the drill motors, and hypothetically, we are considering clamping them on with large U-bolts. Does anyone have any wisdom about mounting motors with U-bolts? Or is it a bad idea in general?

: Thanks
: Patrick Dingle
: Team 639 - Ithaca High School & Cornell University
: [email protected]

I don’t think you’ll get enough contact area between the oddly shaped housing and the u-bolt ID. The clamping force will be distributed over these small areas > stress > housing distortion >clamp relaxation> bolt retorquing. All that could compromise alignment of your drivetrain.

Our first year - we milled the handles off to achieve a flat mounting surface (housings sitting upright)and confined the now oval shaped base within a lexan plate slotted to receive hose clamps (2). There was some loosening, but worked OK.

Last year we again milled handles off and milled a flat in the speed selector plate for an inverted mount. We then cut 1" HDPE block with slots to capture the handle bore and bolted through it to the baseplate A lot of effort - but worked well. We also incorporated Dr. Joe’s motor mod (HIGHLY RECOMMENDED) and dispensed w/ the clutches.

This year we’ve taken the advice of Drs. Johnson and Baker in mounting our drill assemblies, resulting in a structurally sound, accessible and cooler (thermal and visual aspects) design.

If all that is way too much work - I’d use hose clamps first and u-bolts only if I could “gasket” the clamping surface of the housing to better distribute the clamp force over the surface.

e-mail me w/ any questions @ [email protected]

call me kenny TEAM 248 - Phila. HS for Girls

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