LifeTrac IV/Research Development/Design Criteria

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In order to determine the design the LifeTrac we need initial design specifications. These criteria are goals to aim for during the design analysis process.

Criteria Summary

Criteria Description
Speed 5 mph in 4 wheel drive
Power Power Cubes, 14 gpm auxiliary hydraulics per Power Cube, 1 channel
Motors Four 32 cubic inch hydraulic motors
Vehicle Weight >3000 lb
Load Carrying Capacity 3000 lb
Max Lifting Height 115" from ground
Attachment Plate Range of Motion +15deg / -50deg from horizontal

Detailed Information

Please provide rational and discussion of the specifications here.

Vehicle Speed

5 mph in 4 wheel drive

Vehicle Power

One or two powercubes can be used to provide power to the vehicle.

Drive Motors

Vehicle weight

The heavier the vehicle the higher the load carrying capacity (counter weight to the tipping force of a load). However this must be balanced with motor capability.

Load carrying capacity

  • 3000lb load carrying capacity is chosen as the requirement because that is the weight of a full pallet of compressed earth bricks.
  • Engineering analysis should be performed with a structural safety factor of at least 3.
  • Verification of the load carrying capacity based on geometry and weights should be done here
  • Half the tipping load should be the actual load carrying rating (provided no structural problems)
  • Tipping load to be calculated when load farthest away from vehicle due to radial arm travel

Max Lifting Height

Current lifting height is measured from the the ground to the bottom of the QA plate in the neutral forward facing position when the arms are in the full up position.

115" was chosen as that height allows clearance for when the soil pulverizer is dumping soil into the hopper of the CEB Press.

Bobcats have a range between 95" and 115", so 115" looks to be at the top of this range and not an unreasonable spec. (See the discussion of this page for more details)

Wanted: Does anyone know the industry standard for skid steers?

Attachment Plate Range of Motion

From the forward facing neutral position on the ground, the QA plate should be able to rotate 15deg upwards. This allows for pallets to be tilted towards the vehicle before lifting vertically with the loader arms. This is useful for picking up objects on downward slopes as well.

The QA plate should also be able to rotate 50deg downwards from the horizontal. This is important for dumping contents of the soil pulverizer or dirt bucket into the CEB Press hopper or other high locations such as a pick-up truck bed. The more range in the downward direction the better, but this is generally constrained by structural geometry.