Step 1: Making V-box: deforming PVC tube
The form of the V-bow allows the dog to insert the ball into the box correctly. It doesn't matter in from which direction he is approaching the box, the ball will always end up in the slot.
You start from a standard PVC tube with an inner diameter of 12 centimeters. Cut it to a length of 22 centimeters. Then take a hot air blower to heat the tube so it can easily be deformed. Then apply a wooden planch with dimensions 10cm x 30cm and insert it in the PVC tube. Apply pressure until the back of the tube is flattened.
The back should be flattened because this side will be next to the legs of the person in the wheelchair. Comfort and volume reduction are the main reasons for the deformation of the tube.
Step 2: Making V-box: Slope and slot
From several tests, we concluded that the suitable slope towards the slot should be 45 degrees. The slot is necessary to attach the collar to the wheelchair so that the dog can independently put on and take off his leash and collar.
The width of the slot depends on the outer diameter of small, transparent tube that will be shown in step 6. Here we use a width of 1 centimeter. Make sure that the slot is deep enough: here it is 7.5 centimeters. Don't forget to round the corners so that the rope containing the golf ball is guided smoothly into the slot. Finish it with a file and sandpaper in order to remove chips so that neither the dog nor his owner can hurt himself.
Step 3: Making V-box: Fixing holes
In order to fix an iron bar to the V-box, some holes need to be drilled. We drilled 6 holes with the same diameter of the bolts (6 millimeters). These holes are at the same position as the wholes that will be drilled in the iron bar. Here the horizontal distance between two holes is 6 centimeters. We made six holes so that the user can chose the most comfortable position of the box.
Step 4: Fixation bar To create a fixation bar, you need an iron bar, an iron saw, a drill and brazing tools along with tin.
First cut the iron bar in 3 pieces, each time at an angle of 45 degrees.
The first part measures 12.5 centimeters.
The second part measures 9 centimeters.
The third part measures 20 centimeters.
Each time the longest distance was measured.
Connect the parts using the Brazer technique. Be careful: cool the bar with cold water before touching it with bare hands. Drill two holes in the piece that measures 12.5 centimeters in order to attach it to the V-box using the bolts, nuts and washers. The next step is inserting the bar into the tube under the armrest. Clamp the bar with a bolt shown on the last picture. Finish the bar with a file and sandpaper to achieve a clean result.
The tube under the armrest is a standard part that can easily be bought and attached to any electric wheelchair. This fixation method is just a suggestion. There exist several ways to connect this part to a wheelchair, depending on the type of wheelchair.
Step 5: Collar and detaching system
The ball that will be attached to the collar first needs a hole through which a rope can be put. The rope has a length of 15 centimeters, but this dimension will vary from dog to dog. Make a firm knot at the end of the rope to fix the rope to the ball. Then apply a small PVC tube to protect the rope and to prevent that it will twist and weave when the dog wants to grab it. It is important that the rope is connected to the collar firmly. We sewed the rope on the fabric collar.
Step 6: Making leash
To prevent the rope from fraying, we melted the ends of each rope before we started braiding.
Cut 3 ropes at a length of 160 centimeters to become a leash with a length of 70 centimeters. Leashes that are normally used for assistant dogs are always more or less 70 centimeters. Fold the 3 ropes in two, around the ring on the collar. We start braiding around the ring, because this connection should be as light as possible to make the system function properly. The technique that is applied is the classic braiding technique, which is very easy, only you should use two ropes at a time instead of one. In this way a double braid is created. The last step is to apply a little bit of glue at the end of the braid. Fold the braid and use one of the six ropes to twist around the little loop. This loop can be used to attach the leash to the wheelchair, for example by putting it over a hook.
Author: Korneel De Viaene found on Instructables.com