Three-wheel cargo cart with adjustable handle height
View Patent ↗A hand propelled three wheeled cart for transporting miscellaneous cargo. The basic cart has a single front wheel with two solid rear supports, such as a standard wheelbarrow. The two rear wheels are attached to a lever that is pivotally connected to the lever mounting support brackets. Lifting the handles pries the two rear wheels, into position, elevating the rear cart support legs off the ground. This cam action reduces the operators lifting effort and improves the lateral stability of the cart. Releasing the handles automatically anchors the cart.
1. A three-wheeled cargo cart
comprising a tub;
a right side tub rear support; a
left side tub rear support;
a first front wheel configured to rotate on a first front wheel axle;
a right side tub lifting handle having a proximal end, and a distal end supported by the first front wheel axle;
a left side tub lifting handle having a proximal end, and a distal end supported by the first front wheel axle;
a right side lever and wheel assembly comprising
a lever having a proximal end and a distal end and a pivot point provided between the proximal end and the distal end,
a lever handle provided on the proximal end of the lever, and
a right side rear wheel configured to rotate in proximity to the distal end of the lever;
a left side lever and wheel assembly comprising
a lever having a proximal end and a distal end and a pivot point provided between the proximal end and the distal end,
a lever handle provided on the proximal end of the lever, and
a left side rear wheel configured to rotate in proximity to the distal end of the lever;
a right hand pivot bracket attached to the tub or attached to the right lifting handle in proximity to the proximal end of the right lifting handle, the right hand pivot bracket comprising
a plurality of adjustment notches, and
a right lever stop cam;
a left hand pivot bracket attached to the tub or attached to the right lifting handle in proximity to the proximal end of the right lifting handle, the right hand pivot bracket comprising
a plurality of adjustment notches, and a
left lever stop cam; and
a crossmember shaft comprising
a right end portion pivotally attached to the right side lever pivot point and to the right hand pivot bracket thereby permitting the right side lever to pivot relative to the right hand pivot bracket, so that as the right side handle is raised, the right rear wheel is lowered, and as the right side handle is lowered, the right rear wheel is raised, and
a left end portion pivotally attached to the left side lever pivot point and to the left hand pivot bracket thereby permitting the left side lever to pivot relative to the left hand pivot bracket, so that as the left side handle is raised, the left rear wheel is lowered, and as the left side handle is lowered, the left rear wheel is raised.
2. The three-wheeled cargo cart of claim 1 further
comprising a stop cross bar comprising
a right end insertable into a selected adjustment notch of the plurality of adjustment notches in the right hand pivot bracket, and
a left end insertable into a selected adjustment notch of the plurality of adjustment notches in the left hand pivot bracket.
3. The three-wheeled cargo cart of claim 1 further comprising a right side tensioning element and a left side tensioning element.
4. The three-wheeled cargo cart of claim 3 wherein
the right hand pivot bracket further comprises a bolt or peg retention feature; and
the right side tensioning element further comprises an elastic band looped over a right end portion of the stop cross bar and looped over the bolt or peg retention feature, such that the elastic band holds the right end portion of the stop cross bar in one of the plurality of adjustment notches.
5. The three-wheeled cargo cart of claim 3 wherein
the right hand pivot bracket further comprises a bolt, peg, or slot retention feature; and
the right side tensioning element further comprises a spring having a first end attached to a right end portion of the crossmember stop bar and a second end attached to the bolt, peg, or slot retention feature, such that the spring holds the right end portion of the crossmember stop bar in one of the plurality of adjustment notches, thereby securing the right side lever at a desired pivot position.
6. The three-wheeled cargo cart of claim 3 further comprising
a rigid coupling extending between the right hand pivot bracket and the left hand pivot bracket.
7. The three-wheeled cargo cart of claim 1 further comprising a second front wheel.
8. The three-wheeled cargo cart of claim 1 wherein
the right hand pivot bracket, the left hand pivot bracket, the right rear support, and the left rear support are integral to the tub.
9. The three-wheeled cargo cart of claim 1 further
comprising a right rear wheel load sensor;
a left rear wheel load sensor; and
an alarm activated by the right and left rear load sensor.
10. The wheelbarrow conversion kit of claim 1 wherein
the right hand pivot bracket is attached to a right lifting handle which is cut off in proximity to the right rear support; and
the left hand pivot bracket is attached to a left lifting handle which is cut off in proximity to the left rear support.
11. A method of adjusting a three-wheeled cargo cart to minimize the downward travel of the handles, the method comprising
providing a three wheel cart comprising a
tub;
a right side tub rear support; a
left side tub rear support;
a first front wheel configured to rotate on a first front wheel axle;
a right side tub lifting handle having a proximal end, and a distal end supported by the first front wheel axle;
a left side tub lifting handle having a proximal end, and a distal end supported by the first front wheel axle;
a right side lever and wheel assembly comprising
a lever having a proximal end and a distal end and a pivot point provided between the proximal end and the distal end,
a lever handle provided on the proximal end of the lever, and
a right side rear wheel configured to rotate in proximity to the distal end of the lever;
a left side lever and wheel assembly comprising
a lever having a proximal end and a distal end and a pivot point provided between the proximal end and the distal end,
a lever handle provided on the proximal end of the lever, and
a left side rear wheel configured to rotate in proximity to the distal end of the lever;
a right hand pivot bracket attached to the tub or attached to the right lifting handle in proximity to the proximal end of the right lifting handle, the right hand pivot bracket comprising
a plurality of adjustment notches, and
a right lever stop cam;
a left hand pivot bracket attached to the tub or attached to the right lifting handle in proximity to the proximal end of the right lifting handle, the right hand pivot bracket comprising
a plurality of adjustment notches, and a
left lever stop cam; and
a crossmember shaft comprising
a right end portion pivotally attached to the right side lever pivot point and to the right hand pivot bracket thereby permitting the right side lever to pivot relative to the right hand pivot bracket, so that as the right side handle is raised, the right rear wheel is lowered, and as the right side handle is lowered, the right rear wheel is raised, and
a left end portion pivotally attached to the left side lever pivot point and to the left hand pivot bracket thereby permitting the left side lever to pivot relative to the left hand pivot bracket, so that as the left side handle is raised, the left rear wheel is lowered, and as the left side handle is lowered, the left rear wheel is raised; and
a stop cross bar comprising
a right end insertable into a selected adjustment notch of the plurality of adjustment notches in the right hand pivot bracket, and
a left end insertable into a selected adjustment notch of the plurality of adjustment notches in the left hand pivot bracket; and
adjusting the right lever stop cam and the left lever stop cam by
with the cart parked on a flat surface, articulating the right lever and the left lever so that the right wheel and left wheel are resting on the surface,
rotating the right lever stop cam and the left lever stop cam until they touch the right lever and left lever, respectively, and
securing right lever stop cam and the left lever stop cam.
12. A wheelbarrow conversion kit, for converting a wheelbarrow comprising a tub, a frontwheel, a right and a left rear support, a right support arm, and a left support arm, the wheelbarrow conversion kit comprising
a right side lever and wheel assembly comprising
a lever having a proximal end and a distal end and a pivot point provided between the proximal end and the distal end,
a lever handle provided on the proximal end of the lever, and
a right side rear wheel configured to rotate in proximity to the distal end of the lever;
a left side lever and wheel assembly comprising
a lever having a proximal end and a distal end and a pivot point provided between the proximal end and the distal end,
a lever handle provided on the proximal end of the lever, and
a left side rear wheel configured to rotate in proximity to the distal end of the lever;
a right hand pivot bracket attached to the tub or attached to the right lifting handle in proximity to the proximal end of the right lifting handle, the right hand pivot bracket comprising
a plurality of adjustment notches, and
a right lever stop cam;
a left hand pivot bracket attached to the tub or attached to the right lifting handle in proximity to the proximal end of the right lifting handle, the right hand pivot bracket comprising
a plurality of adjustment notches, and a
left lever stop cam; and
a crossmember shaft comprising
a right end portion pivotally attached to the right side lever pivot point and to the right hand pivot bracket thereby permitting the right side lever to pivot relative to the right hand pivot bracket, so that as the right side handle is raised, the right rear wheel is lowered, and as the right side handle is lowered, the right rear wheel is raised, and
a left end portion pivotally attached to the left side lever pivot point and to the left hand pivot bracket thereby permitting the left side lever to pivot relative to the left hand pivot bracket, so that as the left side handle is raised, the left rear wheel is lowered, and as the left side handle is lowered, the left rear wheel is raised.
13. The wheelbarrow conversion kit of claim 12 further
comprising a stop cross bar comprising
a right end insert-able into a selected adjustment notch of the plurality of adjustment notches in the right hand pivot bracket, and
a left end insert-able into a selected adjustment notch of the plurality of adjustment notches in the left hand pivot bracket.
14. The wheelbarrow conversion kit of claim 12 further comprises a right side spring or elastic band tensioning element and a left side spring or elastic band tensioning element.
15. The wheelbarrow conversion kit of claim 12 further comprising
a rigid coupling extending between the right hand pivot bracket and the left hand pivot bracket.
16. The wheelbarrow conversion kit of claim 12 further
comprising a right rear wheel load sensor;
a left rear wheel load sensor; and
an alarm activated by the right and left rear load sensor.
17. The wheelbarrow conversion kit of claim 12 wherein
the right side lever and wheel assembly, the left side lever and wheel assembly, the right hand pivot bracket, the left hand pivot bracket, and the crossmember shaft are configured
to permit the right side lever to pivot relative to the right hand pivot bracket, so that as the right side handle is raised, the right rear wheel is lowered below a bottom portion of the right rear support, and as the right side handle is lowered, the right rear wheel is raised above the bottom portion of the right rear support, and
to permit the left side lever to pivot relative to the left hand pivot bracket, so that as the left side handle is raised, the left rear wheel is lowered below a bottom portion of the left rear support, and as the left side handle is lowered, the left rear wheel is raised above the bottom portion of the left rear support.
18. The wheelbarrow conversion kit of claim 12 wherein
the right side lever and wheel assembly, the left side lever and wheel assembly, the right hand pivot bracket, the left hand pivot bracket, and the crossmember shaft are configured to permit the converted wheelbarrow to be operated in a first single plank mode where an operator lifts the rear two wheels off the ground to obtain normal wheelbarrow maneuverability, or to be operated in a rear wheel mode where an operator lowers the right and left wheels to reduce lifting effort and to improve lateral stability.
19. The wheelbarrow conversion kit of claim 18 wherein
the right side lever and wheel assembly, the left side lever and wheel assembly, the right hand pivot bracket, the left hand pivot bracket, and the crossmember shaft are configured to permit the operator to independently select desired heights of the right lever handle and the left lever handle.
20. The wheelbarrow conversion kit of claim 18 wherein
the right side lever and wheel assembly, the left side lever and wheel assembly, the right hand pivot bracket, the left hand pivot bracket, and the crossmember shaft are configured to require the right lever handle and the left lever handle to be adjustable to a common height.
21. The wheelbarrow conversion kit of claim 12 wherein
the right side lever and wheel assembly, the left side lever and wheel assembly, the right hand pivot bracket, the left hand pivot bracket, and the crossmember shaft are configured
to permit the right side lever to pivot in a cam action relative to the right hand pivot bracket right lever stop cam, and
to permit the left side lever to pivot in a cam action relative to the left hand pivot bracket left lever stop cam.