Wooden hopping toys
I cannot believe that I have found so many wooden toy projects - and just after Christmas to boot. These wooden hopping toys, movable wooden dinosaurs and ping-pong gun would make great gifts.
To make this project the designer found some internet photos of wooden hopping kangaroo toys and worked backwards by playing around with some variations to make a working model of a kangaroo toy. The kangaroo hops really well, with two different legs for a short hop or longer hop.
Then I wanted to go a step further and make some other kind of hopping animal toy.... that's when I found out that it is HARD to make even a simple mechanical toy work the way you want it to. After many rabbit body variations and different leg designs - varying centre pivot point, body length, leg height etc... I managed to design a hopping rabbit version that really hops. In hindsight, I learned some key factors to consider for the design of hopping toys - mainly, BALANCE and how far you deviate from your prototype design. Making a duck-bill dinosaur from the kangaroo pattern went a lot faster than the rabbit - fewer variables to control.
Anyway, here's what I learned, may it help you design your own hopping toys faster and with less effort than I expended.
YOU WILL NEED:
Pine, supawood or plywood 19mm thick
Optional thin plywood (for legs) - 6mm thick
3mm dowel or bamboo skewer
2 washers, centre hole a bit larger than 6mm (or axle size).
Scroll saw or hand coping saw
Sandpaper and files
Acrylic craft paint or other wood surface finish
Wood board, clip board, or book to provide inclined plane down which the toy hops
1. Drill holes in legs and body. Lower leg hole and eye should be 3mm holes. Upper leg hole 6mm holes to fit pivot axle made from 6mm dowel. Body pivot hole should be greater than 3mm to allow the leg axle to freely rotate. I drilled an 8mm hole.
2. Cut dowels for axle and leg stop - length should be width of body, twice the leg width and a little extra for the washers.
3. Sand edges smooth, clean up drill holes, sand dowels if needed.
4. Assemble: Insert dowels into one leg. Add washer to axle (pivot dowel), insert into body, add the other washer and insert into second leg. Align dowels correctly and press together for a snug fit. DO NOT GLUE the dowel into the holes until you have tested hopping action.
5. The 3mm dowel on the lower part of the leg should swing freely along the belly until it hit the 'stops'/bumps by the front leg and tail. These stops constrain the length of the hop and keep the legs below the body's centre of gravity. If the stop is not there, the legs collapse and you don't get any hops.
6. Use a rough pieces of wood, back of clip board or book to make a ramp, around 25 - 30 degrees slope.
7. Lift kangaroo tail and gently drop, which should start a hopping motion. Vary angle of slope until the kangaroo hops. If the front leg slips or slides down the slope instead of acting as a pivot point, use a little bit of masking tape or rubber cement to add some friction, and/or abrade leg bottom with a file or coarse sandpaper.
8. If kangaroo still doesn't hop, see the section on tweaking the design for more suggestions.
It's a good idea to paint the animals after you have tested them but before final assembly. Push a screwdriver through the centre hole to support them on a drinking glass while you paint with acrylic paints.
Note: this type of toy has small parts which could pose a CHOKING HAZARD, so not for a child under 3-years-old.