Introduction: Powerlift Tractor Step Assistive Technology

By Visit Disability Work Tools!
About: I started out my agricultural engineering career serving farmers with disabilities for Breaking New Ground at Purdue University. I then moved to Lowell, Michigan to be a dairy farmer and started a vegetable ma…

A powerlift step uses a 12V electric linear actuator to raise a worker to a utility tractor operator’s station without climbing. The steps up to the operator’s stations are steep and tall. Workers often cannot safely climb and lift themselves with one leg, especially when they have knee surgery. They can use a powerlift step to raise up and then walk directly from the step to the tractor seat without climbing. The powerlift step needs 300-pound capacity, raise at least 16-inches, have 12” x 14” standing surface, not damage crops during tractor use, and maintain existing tractor ground clearance. This simple design uses a 'tube sliding in a tube' concept.

Supplies

1pc Bar grate 14-1/2" wide x 12" deep

1pc 1-1/2"x1-1/2"x1/4" angle 14-1/2" long step support.

2pcs 1/4"x2" flat stock 15" long (This is the toe kick and bar grate nose.)

1pc 1/4"x5"x12" long flat stock (This is the fixed machine mounting plate.)

1pc 1/4"x4"x12" long flat stock (This is the 'sandwich' machine mounting plate.)

1pc 1/4" wall 1-1/2" sq tube 4" long (This is the lower actuator mount tube.)

1 pc 1/4" wall 1-1/2" sq tube 16" long (This is the step platform support.)

1 pc 1/4" wall 1-1/2" sq tube 32" long (This is the slide tube.)

1pc 3/16" wall 2" sq tube 48" long (This is the vertical guide mast.)

1pc 3/16" wall 2" sq tube 18" long (This is the machine mounting frame.)

1pc 1/4" x 2" flat stock (This is the vertical guide mast gusset.)

1 pc 1/2-13 x3-1/2" bolt upper actuator mounting bolt

1pc 1/2-13x5" lower actuator mounting bolt.

850-pound 12V electric linear actuator 16-inch stroke (www.progressiveautomations.com Model: PA-17-16-850)

12V electric controller for actuator (www.summitracing.com item SUM-931200-19)



Step 1: Cut Your Parts

Prepare area for fabrication, clean, organize and gather necessary materials. Cut out bar grate step material, trim ends of bars to square remove sharp edges and burrs. Cut out remaining materials found in supplies list, remove sharp edges and burrs.

Step 2: Platform Safety Welding

A smooth 'nose' bar on the front of the step platform will help prevent tripping on the sharp corners of the bar grate. A toe kick bar on the back of the platform will keep feet safely on the platform. Place and attach step nose and toe kick in an off set fashion so that the top of nose sits flush with step top, and toe kick top extends above step to prevent toes extending beyond step which may cause injury. Tack in place, then run quality welds on each bar minimum one side.

Step 3: Slide Tube Framing

Drill 1/2" hole through both sides of lower actuator mount tube (1/4" wall, 1-1/2" sq tube, 4" long) 3/4" from end, centered within the 1-1/2" tube. Place (note orientation) and tack weld to step platform support tube (1/4" wall 1-1/2" sq tube, 16-1/2" long), once square, finish welding all joints. Place and square vertical slide tube (1/4" wall, 1-1/2" sq tube, 32" long) tack weld in place (note orientation).

Step 4: Platform Attachment

  1. Place the bar grate from "step 2" on the platform support tube from "step 3" offset by 2-inches in both directions as shown.
  2. Tack weld in place.
  3. Add bar grate step support ( 1/4" thick, 1-1/2x1-1/2 angle, 14-1/2" long) as shown for added step support.
  4. Once placed and square, weld securely in place as shown.

Step 5: Vertical Guide Mast

  1. Position the machine mounting frame (3/16" wall, 2" sq tube, 18" long) flush and square to the bottom end of the vertical guide mast (3/16" wall, 2" sq tube, 48" long).
  2. Tack weld the mounting frame to the guide mast and double check to make sure it is square and flush.
  3. Add support gusset (1/4" thick, 2" wide, 4" long) to intersection of tubes as shown.
  4. Weld all joints.
  5. Place machine mounting plate (1/4" thick, 5" wide, 14-1/2" long) flush with the end of the machine mounting frame and offset 3/4 inch.
  6. Weld the machine mounting plate onto the mounting frame as shown.

NOTE: The machine mounting frame and plate should be configured based on your specific tractor. Sometimes the mounting plate needs to be vertical vs. horizontal so it can bolt into existing holes on the tractor frame. Sometimes it needs to be mounted part way up the vertical guide mast.

Step 6: Assembly & Actuator Attachment

  1. Insert the slide tube into the vertical guide mast with mounting frame parallel to the step platform.
  2. Install lower 1/2-13 x 5" bolt through the hole in the slide tube.
  3. Remove the actuator from its delivery packaging.
  4. Mount the small end of the actuator on the slide tube bolt.
  5. Mark proper location for 1/2-13 x3-1/2" upper actuator mounting bolt.
  6. Remove the actuator and weld the mounting bolt securely in place on the vertical guide mast.
  7. If desired weld a hand grip on the vertical guide mast for a more stable transport.

NOTE: When assembling slide tube into the vertical mast guide, make sure that at no time the step platform 'swings' under the mounting frame in such a way that the user's feet might be pinched.

Step 7: Installation on Tractor

  1. Place the mounting plate of the powerlift step on the tractor operator station and clamp in place.
  2. Place a matching steel plate underneath the operator station and clamp in place. The mounting plates above and below will 'sandwich' the operator station surface.
  3. Drill through both steel plates and the operator station and through bolt with 3/8" grade 8 bolts and locking nuts.
  4. If needed, weld or bolt additional steel material to reinforce the operator station. The tractor shown has had a 1 1/2-inch steel tube welded onto the loader bracket to support the weight of the powerlift step on the operator station.
  5. Connect the 12V controller wires to the powerlift step actuator wires.
  6. Connect the controller wires to the tractor battery terminals. Always include a fused link near the battery to protect the controller and actuator from overheating.
  7. A heavy duty tractor magnet can be used to mount the controller in a convenient location for operating the lift while holding onto the vertical guide mast for support.

Step 8: Powerlift Step Safety

  1. The operator weight limit is 300 pounds. 
  2. Always hold the vertical guide mast or rigid structure on tractor when lifting or lowering. 
  3. As medically necessary, have an attendant nearby or on call to assist while operating the powerlift step and a cell phone to call for assistance.
  4. The operator is responsible to follow medical advice regarding appropriate work tasks for their physical condition. 
  5. Beware of pinch points where the actuator rod retracts. Keep feet on step surface while moving up or down.
  6. Do not operate the powerlift step if you are unable to easily control the up and down motion of with the control switch.


Step 9: Powerlift Step Maintenance

  1. Stand on the platform and grip handle with one hand and hold the controller in the other.
  2. Press the up or down button on the controller to move.
  3. Make sure the platform is raised at least 15” above the ground before driving the equipment. Raising the platform to maximum height during tractor operation will tuck it closer to the cab and reduce the likelihood of striking the step on obstacles.
  4. Inspect the bolts and welds daily during use for wear. Maintain paint.
  5. Be careful to not trip when stepping on and off the platform.
  6. Raising or lowering the platform to maximum position and continuing to hold the controller button excessively will damage the actuator.