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This Instructable is for a wheelchair carrier to attach to the tow ball of a standard car.  This is primarily for someone who has to transport a passenger needing a wheelchair but without easy access to get the wheelchair in and out of the car.

This idea came about when I tried to find something to assist my mother to take my grandma and her wheelchair out shopping.  My mum is unable to lift the wheelchair in and out of the boot – and the options out there for tow ball fitted wheelchair carriers were very limited and still required significant lifting.

The photo is of prototype 5.  It is almost the final design.  Prototype 5 + fix 4 bugs = final design!

The drawing is the final design.  Ooh, pretty :)

This wheelchair holder has been designed to:
  •  minimise lifting
  •  fold up when empty
  •  be as easy as possible to build
  •  still allow rear access to the car
  •  be easily removable
  •  be as lightweight as possible, and
  •  only use materials readily available at a big hardware store.

To complete this project, you will need to have access to a welder and a basic knowledge of welding.  An angle grinder will also come in handy but if you want the extra effort, a hacksaw will do.

Final special notes: 
This is designed to load a wheelchair from the footpath side for left-hand drive countries (I'm in Australia).  I recommend that you reverse the images in these instructions if you are in a right-hand drive country.
Please check the applicable laws in your state before using.

Step 1: What You Need

Tools:
  •  welder and welding bits (gloves, mask, rods, wire brush)
  •  drill and assorted drill bits
  •  angle grinder and/or hacksaw (preferably both)
  •  self-drilling screws (approx 10mm long) or pop-rivets
  •  metal file (preferably one with both a flat and round side)
  •  pencil or marker pen to mark metal
  •  hammer and large screw (or nail or other pointy hard metal-thing) to pre-mark holes
  •  some useful combination of workbench/saw horses and vices/clamps.

Materials:

  •  aluminium plate - 300mm x 350mm
  •  3 chain links at least 40mm long
  •  3m (3000mm) of 25mm box section (steel tubing with a square cross-section)
  •  3m of 20mm box section
  •  3m of 25mm angle iron (steel lengths with an L shape cross-section)
  •  2 steel brackets - 3mm thick - 240mm x 50mm x 80mm (see Step 7 for a picture)
  •  door latch (see Step 5 for a picture of the preferred type)
  •  self-drilling screws or pop-rivets - 10mm long
  •  1 x bolt - 40mm long, approx 6.5mm in diameter
  •  1 x bolt - 60mm long, approx 6.5mm in diameter
  •  1 x nylon locking nut to suit shorter bolt
  •  2 x washers to suit shorter bolt
  •  1 x normal nut to suit longer bolt
  •  1 x wing nut to suit longer bolt

  •  2 elastic straps with hooks on either end - approx 600mm long when not being stretched (these are to hold the wheelchair in place during transporting and to hold the carrier in the folded up position when not being used
  •  1 elastic strap with hooks on either end - approx 450mm long when not being stretched (this is to hold the foot pedal up during transporting

Step 2: Building the Main Frame

a) Cut the materials to the lengths and amounts shown in Image 1.

b) Weld hinges between the two long sections, 150mm from each end.  Remember to leave a 4mm gap between the lengths (see Image 2) 

c) Weld shorter box section (320mm) at right-angles underneath the hinged lengths (using the small pieces of angle iron as reinforcing brackets).  Please do NOT weld to both long sections, only the one shown in Image 3 with the brackets attached.
After welding, the long length at the back should still be able to swing upwards on the hinges.

d) Weld the hinges to the shorter length (the one sticking out).  The hinges should be at least 40mm from the inner and outer edges (see Image 4).  Eventually then ramp will attach onto this.  

e) Weld vertical frame together (150mm, 215mm and 125mm box section lengths).  Two important notes see (Image 5):
  •  there should be a hole pointing up on one side.  A pole will insert into this later so you will need to keep it clear of welding blobs, and
  •  we will be welding more stuff onto the back of this frame in Step 2-f.  I suggest just adding a few welds to hold it together, complete the construction in 2-f, then weld all the joins.

f) Weld the two 100mm sections to the back of the frame, see Image 6.  It is important to get them as parallel as possible because posts attached to the mounting plate will slide into these sections.

Step 3: The Ramp

a) Cut the materials to the lengths and amounts shown in Image 7.

b) Weld the 3 x 300mm box sections in a ladder formation to the 2 x 1000mm angle iron lengths.  Also weld the 2x 300mm half-box section lengths and the 2x half-chain links on.  See Image 8 for measurements.

Important: make sure the 300mm lengths are at right-angles to the long lengths (otherwise the ramp may foul the main frame). Also, to fit the bars in properly, you may need to trim the bottom edge from the ends (see zoom on Image 8).

c) Attach main frame to the ramp by welding the hinges to the middle 300mm box section (the right-hand end of the main frame should line up with the end of the ramp).  See Image 9

d) Weld front wheel support bar (300mm box section and 2 x 60mm box section, welded in a U shape) in place 150mm from the right-hand side of the ramp as per Image 9.

Step 4: The Foot Pedal

a) Cut the materials to the lengths and amounts shown in Image 10.

b) Cut one of the 80mm angle irons to remove a 25mm section.  See Image 11.

c) Drill the 2 x 80mm angle irons (as per Image 12) and weld to the right-hand end of the ramp (the piece cut in Step 4-b should line up with the inner edge of the ramp and both pieces should stick up 25mm above the ramp face.  See Image 12.

Important: do not weld inside the cavity made by the two pieces as another section will bolt in here later.

d) Drill and round off the end of the 400mm box section as per Image 13.

e) Weld together the 400mm and 50mm box sections into al L shape.  Weld the 1/2 chain link onto the side of this L.  See Image 14.

f) Bolt the L section into the angle irons (using a bolt, 2 washers and a nylon locking nut) and ensure that it can easily pivot, from pointing down, up through 270 degrees.

Step 5: Adding the Ramp Latch

Fit the door handle as per Image 15 and the manufacturers instructions.  Please note the direction that the handle should turn, as shown in Image 15.

Special Note: To stop the latch from closing and then continuing past horizontal, you will need to take a piece of metal and weld it to the main frame underneath where the latch is. If this is confusing, you can skip this step for the moment, it will become obvious during the latch testing and my instructions will suddenly make more sense.

Step 6: The Securing Bar

a) Cut a 20mm box section to a length of 600mm and locate a full chain link.  See Image 16.

b) Weld the chain link to the top of the bar so that half of the link's length is above the top of the bar.  Weld a nut or blob of weld to the bar 140mm from the bottom.  This piece of metal should stick out at least 5mm.  It will stop the bar from inserting too far when the project is put together.  See Image 17.

Step 7: The Mounting Plate

a) Cut the materials to the lengths and amounts shown in Image 18.

b) Weld the 2 x steel brackets together to create a single, double-thickness bracket.  Weld the 2 x 150mm box section to the shorter face of the plate so that the ends extend up past the bracket bend.  See Image 19.

Important note: the 150mm sections MUST be parallel or the frame won't slide down onto these pieces.  I suggest you:
  •  weld the first 150mm piece in place, ensuring it is at right-angles to the plate
  •  attach the second piece as accurately as possible using a single, small tack of weld
  •  adjust with a hammer (or cutting and rewelding) and, when lined up and sliding easily onto the mounts on the main frame, then finish the welds.

c) Weld the 2 x angle irons underneath the bracket, from the edge in on a 45 degree angle. See Image 20.

d) Measure your tow bar and drill the hole for the tow bar bolt.  If tow bar not available, drill the hole in the centre of the bracket's top section.

Step 8: Putting It Together

a) Attach the aluminium pieces onto the ramp using the screws or pop-rivets.

b) Slide the mounting plate up into the rear mounts on the main frame ensuring that there is no fouling.  Grind/file as necessary.

c) Slide the securing bar into place into the top of the frame and ensure that it does not foul on anything. Grind/file as necessary.

d) Take the long bolt and the wing nut.  Feed the wing nut onto the bolt and place a welding tack onto the side of the bolt head to keep the wing nut in place.  See Image 21.

e) Drill a hole in the side of one of the mounts on the rear of the frame.  You should be drilling an 8mm hole through two box sections (one inside the other).  Feed the long bolt through this hole and attach the normal nut onto the end.  Do it up so that the bolt is hand tight and place a welding tack onto the nut to secure it to the frame.  Do NOT weld the nut to the bolt.  Now you have a removable bolt, with wing nut end, to stop the frame jumping off the mounting plate.

Step 9: Using the Carrier

No instructables would be complete without instructions for use so...

Unfolding the ramp:
   1   undo the three elastic straps and place them to one side
   2   fold the ramp towards you
   3   fold down the foot pedal

Loading and raising the ramp:
   1   fold the wheelchair so that the sides come together and it becomes thin
   2   push down on the handles to raise the front wheels off the ground
   3   roll the wheelchair on its rear wheels up the ramp until the rear wheels sink part-way into the large hole
   4   lower the front wheels into the smaller wheel hole
   5   hold the wheelchair upright with one hand while you walk to the other side
   6   place your foot onto the foot pedal and push down until the ramp latch engages
   7   secure the wheelchair in place with the two large elastic straps
   8   fold up the foot pedal and use the smaller elastic strap to hold it in place

Lowering the ramp:
   1   undo the elastic strap for the foot pedal and lower the foot pedal
   2   remove the two large elastic straps holding the wheelchair.  Remember, from here on you need to have a hand on the wheelchair to keep it steady
   3   place a small amount of pressure on the foot pedal to take up the weight
   4   turn the latch handle to unlock the ramp
   5   lift the foot to lower the ramp to the ground
   6   push down the handles to raise the small wheels
   7   pull to free the large wheels
   8   roll wheelchair down ramp

Folding the ramp away:
   1   raise ramp so that it is horizontal
   2   fold up foot pedal
   3   lift closest edge of ramp so that it folds up towards car
   4   attach the two large elastic straps to the ramp loops (from one side, up around the securing bar loop and down to the other side)
   5   hook the small elastic strap from the loop on the foot pedal up to the securing bar loop
Fantastic instructions, thank you for sharing.

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