Wheelbarrow construction

1. An improved wheelbarrow construction comprising:

a receptacle unit including an enlarged receptacle body;

a main load support unit operatively connected to said receptacle unit, and a first frame member having a pair of rearwardly extending support arms each provided with adjustable handle means;

a forward wheel assembly operatively connected to said main support unit;

a rear wheel trailer unit comprising a second frame member pivotally secured on one end to the main load support unit and provided on the other end with a pair of wheel assemblies; wherein each of said pair of wheel assemblies comprise: a caster wheel and axle operatively connected to a wheel support bracket having a hollow tubular caster swivel projecting upwardly therefrom;

an automatic brake unit associated with each of the said pair of wheel assemblies, and comprising an elongated brake plunger element including an elongated plunger shaft mounted for reciprocation within the hollow tubular caster shafts of said wheel assemblies, secured on one end to said first frame member; and provided on the other end with an enlarged brake pad, which is adapted to releasably engage the pair of wheel assemblies, wherein the automatic brake unit is disposed intermediate the main load support unit and the rear wheel trailer unit wherein, said first and second frame members comprise generally U-shaped frame members, wherein the pair of rearwardly extending support arms have outboard ends and a cross-piece element that extends between said outboard ends, and the second frame member is provided with a pair of forwardly extending support arms; and

a brake override means disposed intermediate the main load support unit and the rear wheel trailer unit, whereby the brake override means is adapted to hold the said elongated brake plunger element out of engagement with said pair of wheel assemblies to temperarily disable said automatic brake unit.

2. The improved wheelbarrow construction as in claim 1 wherein the brake override means comprises: a generally L-shaped bracket member, pivotally connected to the second frame member, wherein one of the legs of the bracket member forms an actuating lever and the other leg of the bracket member forms a support brace.

3. The improved wheelbarrow construction as in claim 2 wherein the main load support unit is vertically displaceable relative to the wheeled trailer unit and said support brace is dimensioned to engage the cross-piece element of the first frame member at a vertical height sufficient to disengage the said elongated plunger elements from contact with said pair of wheel assemblies.

4. The improved wheelbarrow construction as in claim 1 wherein the adjustable handle means comprise:

a pair of inboard bracket elements pivotally secured to the outboard ends of the support arms on the main load support unit;

angled intermediate handle sections operatively secured to each of the inboard bracket elements; and,

elongated hand grip elements associated with each of the angled intermediate handle sections.

5. The improved wheelbarrow construction as in claim 4 wherein each of the inboard bracket elements is provided with an enlarged forwardly extending fulcrum arm which is operatively connected to said automatic brake unit.

6. The improved wheelbarrow construction as in claim 5 wherein the operative connection between the fulcrum arms and the automatic brake unit comprises:

an adjustable spacer member disposed proximate each end of the cross-piece element of the first generally U-shaped frame member,

7. The improved wheelbarrow construction as in claim 6 wherein the adjustable spacer member comprises:

a generally L-shaped rod element pivotally connected on one end to a yoke element that is mounted on said cross-piece element, wherein the other end of said rod element is provided with threads which cooperate with a plurality of threaded fasteners to captively engage said fulcrum arm.