Self-Jumping and Pogo Bikes and a Cargo Trike

Jacknife design produces a different kind of trick.

It jumps from any flat surface at any time, no ramp.

ULTIMATE AIR, best of twelve prototypes. ULTIMATE AIR, other side. ULTIMATE AIR high. The rider stands on the pedals during the jump. ---------------------------------------------------------------------------- OPERATION OF A JUMP BIKE: All the jump bike versions jackknife the bike frame to thrust the bike frame and rider up from the road to produce the jump. Like when a rider does a bunny hop on a BMX bike. They throw their weight up and then pull the bike up with them. With these bikes, the bike does the work. The rider should pedal during the lifting action to add more height to the jump and again to un-jack- knife the bike upon landing. That way the rider's weight will sling the bike forward as the bike reaches its low position. (A lift spring is helpful to produce an easy, high, clean jump. Then the frame is pushed up by the pushrod on the lift crank plus the spring. This thrusts the rider up and produces the jump. A 10" lift of the bottom bracket occurs in about 50" of forward motion. This geometry produces good jump action while maintaining good road traction, but without creating undue braking reaction. The procedure for any jump is to get up to speed, shift weight in line with the lift axis, draw the feet into the shoe bar, squeeze the lift lever and then let the bike launch the bike and rider. Keep holding the lift lever in. Land and let the lift mechanism push the bike forward as it drops to the low position. This is like dropping onto the back slope of a high, wide speed bump. Release the lift lever when the bike is at the bottom. ---------------------------------------------------------------------------- ULTIMATE AIR is a modified 24" DBX Vanquish full-suspension bike that was made into the present jump bike prototype. The rear shifter was deactivated, but any cog can be selected by manually moving the chain guide while stopped. The front shifter was removed because the chain has to swing down during a jump, but any of the three speeds can be selected manually while stopped. The rear brake lever is used for the lift lever, so that brake was removed. To get as much lift as possible, the stock rear geometry has been modified. A 10" extension from the frame pivot extends the wheelbase while leaving the ground clearance the same when riding low. The suspension fork is stock. The lift cog on the left side of the rear wheel hub is 24T and is bolted to where a brake disc would go. The chainring on the pivoting rear frame is 50T. The circumference of a 24" wheel is 6.3 ft. With a 50:24 ratio, full height is reached in 6.4 ft. Pushrod action is 10" if the crank radius is 5" and this results in a 13" lift. A 4" crank radius produces an 11" lift. The lift-assist spring. This is an essential component. The spring selected depends on the rider's weight and preference. The jackknife-action bikes are coverered by our U.S. 6,209,899 patent, Apr. 3 2001. ----------------------------------------------------------------------------- THE POGO BIKE This version has no mechanical lift, just springs. We noticed that a suspension bike's rear spring alone without the damper allows for a pogo-stick-like action. So the next step was to provide much more travel in front and in back. A long-travel fork in front with fiberglass- bow springs was used. This allows 11 inches of travel. The bows are from two pogo sticks. The pogo stick bow springs. Two rear springs end to end are used in back. This allows 7 inches of travel. The bike could be made lighter by using a telescoping front fork instead of the trolley-on-stanchions used here. The trolley rollers are Delrin. Cruiser bars were needed to hold the rider's feet onto the pedals while jumping. From the other side. This Pogo Bike is U.S. patent number 9,079,628 of 2015. The prototype was constructed using our modest machine shop and it would be easy enough for anyone so interested to make their own. Steel cable was used on the prototype to keep the rear wheel from flopping down when airborne or when the bike is picked up. ----------------------------------------------------------------------------- A CARGO TRIKE A KHS Latte folding bike can be made into a good box-in-front, drive-wheel- in-back cargo trike with front wheels steering. The stem, handlebars, fork, front wheel, front fender and kickstand were removed. The KHS Latte. Where the bike folds will be turned over so it goes down to the head tube under the cargo box. The steer tube is cut away from the fork. The steer tube is welded to a 3" riser tube which is welded to the 1 & 1/2" square steel cross tube under the cargo bed. The central folding joint has been modified. One undersized hole was drilled to 3/8". One place with no hole was drilled to 3/8" for the 5" long bolts. The top holes in the down tube hinge also need to be drilled out at a 20-degree angle for the 5" bolts. A steel plate holds the head tube vertical. The 1/8" steel plate is bent at 20 degrees. The bottom "ear" on the hinge was cut off instead of cutting out the steel plate to accommodate it. The dimensions of the plate. Drill the four 3/8" holes before bending the plate on the dotted line. The bolts required to mount the plate are (2) 3/8" x 5" and (2) 3/8" x 1". Use nylon-locking nuts. The cross tube TIG-welded to the 3" riser from the steer tube is 1/16" wall x 1 1/2" square. The length is determined by the width of the box to be made. The tubing used for the handlebar is 1/2" EMT bent with a standard bender. The ends are in the holes in the forks and held with a 1/4" x 1 1/2" bolts. The fork risers are 1/16" wall x 1 & 1/4" square x 3 & 1/2" high box iron welded to the cross tube and one fork leg is welded to the riser. The fork is welded to the outside of the riser here, but welding it to the front or back of the riser would keep the overall width (36 & 1/2" here) narrower. The frame minus the plywood base for the cargo box. The 1 & 1/2" x 24" long perforated angle iron is bolted to the cross tube. The total weight here is 33 lbs. The trike only has a coaster brake. The trike with 1/4" ply base. The ply is bolted to the perforated angle iron. The box was formed using animal cage mesh 1" x 1" square, 24" x 8 feet. The bottom is thin 24" x 24" aluminum. The mesh is closed with nylon ties and nylon ties secure the mesh to the aluminum which has had holes punched for them. The plywood and the mesh box are light duty designed for recycling aluminum cans and scrap pieces of aluminum. The box full of cans can be lifted off and dumped out. Or the box can be secured to the plywood and a trash bag put into the box. We could not find a rectangular plastic bin of the right size to use for cargo. The trike complete. ____________________________________________________________________________