Diameter (effective) A distance between the bead seats (for the tire), as measured in the plane of the rim and through the axis of the hub which is or will be attached, or which is integral with the rim. Contemporary clincher tires today have wires embedded on both beads of the tire so wires fit inside the edges of the rim to hold the tire in place when it is fully inflated.
His 1882 patent became the ancestor of all clincher tires, the design found on modern bikes and cars. Jeffery, developed an improved tire with a wire that was embedded in the rubber of the tire, and the wire could be tightened onto the rim. Bicycle manufacturer and inventor, Thomas B. The surface for receiving the tube was not very secure thus causing the tires to sometimes come off the rims. Jeffery's 1882 clincher rim patent Design The first pneumatic tires for bicycles were simple tubes in shape secured to the wooden outer concave surfaced circumference of the wheel by glue and air pressure pressing them against it. The design also allows for alternative, purpose-built cart-bodies to be dropped in place on an existing cart chassis.Thomas B. The Malawi Cart was designed so that its body four sidewalls and most of the floor can be easily removed without tools (it is fastened in place by four wooden swivel catches) to facilitate the carriage of long poles and planks. Where available, the far stronger Westrick (or Endrick) pattern rims should be employed. The rims commonly available in Malawi are of the archaic and inherently weak Westwood pattern. In Malawi, the cost of a rear wheel differs from the cost of a front wheel merely by the price of the four extra spokes. They have 40 spokes (as against a front wheels’ 36), their axles are longer and thicker and their ball bearings larger. The rear wheels were chosen over front wheels because of their greater strength.
The Malawi Cart rides on two 28-inch bicycle rear wheels. Several large (8mm x 15mm) bolts were used in the prototype, but when such bolts were found to be unavailable in the nearest large town, widely available and cheaper bicycle rear axles were substituted for them in all later models. Fasteners are common nails, along with a few wood screws and small bolts. The Malawi Cart was designed to require only common lumber and two ordinary bicycle wheels. Designed to require only common lumberĪll of these earlier designs however, have only limited potential for widespread adoption in SSA due to their use of these expensive, difficult-towork and/or hard-to-find building materials. (Sullivan, 1983 Hathway, 1985 Barwell et al. The cart derives from existing bicycle-wheel-handcart designs, most of which have until now been executed in steel, plywood, or some combination of the two.
“ The Malawi Cart” has been designed for smallholder farmers and by city dwellers for whom animal drawn carts are unaffordable or impractical or both. An affordable bicycle-wheel wood-frame handcart has been developed in Malawi for agriculture rural and urban transport.