GrabCAD Backhoe Redesign for Fabrication

Based on backhoe results from GrabCAD - http://grabcad.com/challenges/lifetrac-backhoe

Modifications for Fabrication

Main item: resesign for 'stock steel erector-set, Lego-set-like design while retaining performance and ease of use. Allow for replacement of boom/stick elements with longer or shorter versions.

• Need to work out specifics of rotation mechanism
• Simplify boom and stick for use of standard stock steel like the LifeTrac frame - 4x4x1/4 or x 3/8 tubing
• Design quick attach buckets
• Design for disassembly whenever possible
• Retain design for quick attach (QA) plate with seat.
• Will need to acknowledge tractor steering from the seat - such as additional wheel control valve for LifeTrac wheeels.
• Will need to acknowledge migration to Bobcat standard quick attach plate, with universal breadboard quick attach plate for rapid prototyping of attachments - there is insufficient flexibility in QA attachment with Bobcat standard alone

Questions from Lenny-Wayne Patterson

1. Do you want me to deal with any part of the "Universal-Attachment-Mount" I have some ideas.

• Yes! We would like to go from LifeTrac standard to Bobcat standard quick attach plate.

1. Is there any way to get the files of the LifeTrec Backhoe and Tractor in different formats? Like .STEP or .STL I joined the "GrabCAD" group but I could not open any of the files that were offered.

• Please ask somebody to do that conversion - can Parker do that for you?

1. I didn't notice any mention of Quick Disconnects for the Hydraulics. I'm assuming the Backhoe will feed from the Tractor?

• Yes, all should be quick connect. Even on the backhoe itself, since we are going hypermodular. Since driver is on quick attach, will also need to add wheel/loader control for access by operator when he's not in the cab.

1. I believe the rotating mechanism on the Backhoe is ingenious but would be better served with a single cyl that is double acting, double ended rod, with center piston. i.e. where the body moves side to side and the multi-chain is attached to each end of the body.

• Sure, details need to be worked out.

1. Will the Cylinders be off the shelf parts or will we be designing them as well. I was thinking a cut down Drive Shaft could serve as the body and the End Plates and Piston would have to be machined from Aircraft quality Aluminum. Just thinking outside the box. But from a safety standpoint off the shelf would be best.

• Off shelf, until we recruit a Master Prototyper to fabricate these in house.

1. I have some concerns about the Tractors Lifting arms "rear pivoting point"! They are way to high on the tractor it would tend to top heavy and may even flip. And as it is drawn it seems like you a barely loading the lifting Cyls.

• Right. Limit is 2500 lb right now before back comes off the ground. May want to shorten height of frame.

1. To deal with the steering of the tractor from the backhoe seat I will have to see more details of the tractor. I know that's my problem, right? hehe But do you steer the tractor with hydraulics? Sort of like a tank, right stick controls right wheels and same for the left?

• Yes.