초록

A multi-mode load carrier is convertible to assume a storage mode, a cart mode, and a hand-truck mode. The load carrier includes a rolling base and a base pusher having a handgrip.

대표청구항 ▼

1. A collapsible load carrier comprising a rolling base including a load-support frame, a left front wheel unit mounted for pivotable movement on the load-support frame about a left pivot axis between a folded storage position and an unfolded rolling position, a right front wheel unit mounted for pi

1. A collapsible load carrier comprising a rolling base including a load-support frame, a left front wheel unit mounted for pivotable movement on the load-support frame about a left pivot axis between a folded storage position and an unfolded rolling position, a right front wheel unit mounted for pivotable movement on the load-support frame about a right pivot axis between a folded storage position and an unfolded rolling position, and a spring yieldably pivoting each front wheel unit about its pivot axis normally to assume the folded storage position, the folded storage position associated with a flat storage mode of the load carrier in which front wheels in the front wheel units disengage ground underlying the rolling base and a front wheel in the left front wheel unit is arranged to extend toward a front wheel in the right front wheel unit, and the unfolded rolling position associated with a front-and-rear-wheel cart mode of the load carrier in which the front wheels in the front wheel units are arranged to engage and roll on ground underlying the rolling base and rotate about a common axis of rotation,a base pusher mounted for pivotable movement relative to the load-support frame of the rolling base about a base-pusher pivot axis from a stored position arranged to lie alongside and on top of the load-support frame of the rolling base toward a 2-wheel hand-truck position to lie in generally coplanar relation to the load-support frame of the rolling base to define an included angle of about 180° therebetween, andload-carrier mode changer means for pivoting the left and right front wheel units about their pivot axes to move relative to the load-support frame of the rolling base from the folded storage position to the unfolded rolling position to cause front wheels included in the front wheel units to engage and roll on ground underlying the rolling base in response to pivoting movement of the base pusher relative to the load-support frame about the base-pusher pivot axis from the stored position on top of the load-support frame toward the 2-wheel hand-truck position to cause the rear wheel included in the base pusher to engage and roll on ground underlying the rolling base to establish a 2-wheel hand-truck mode of the load carrier. 2. The load carrier of claim 1, wherein the left front wheel unit includes a wheel support formed to include a cam block and a left front wheel, the right front wheel unit includes a wheel support formed to include a cam block and a right front wheel, and the load carrier mode changer means includes a spreader plate configured to engage cam blocks of the left front wheel unit and the right front wheel unit to move the left front wheel unit and the right front wheel unit toward the unfolded rolling position in response to movement of the base pusher away from the stored position toward the 2-wheel hand-truck position. 3. The load carrier of claim 2, wherein the spreader plate of the load carrier mode changer is coupled to the load support frame of the rolling base to pivot relative to the load support frame of the rolling base in response to movement of the base pusher away from the stored position toward the 2-wheel hand-truck position. 4. The load carrier of claim 1, wherein the load-carrier mode changer means includes a front linkage coupled to the left and right front wheel units and a rear linkage coupled to the base pusher and mounted for movement relative to the front linkage between a first position on the front linkage associated with the flat storage mode and the front-and-rear-wheel cart mode of the load carrier and a second position located on the front linkage between the first position and the front wheel units and associated with the 2-wheel hand-truck mode of the load carrier. 5. The load carrier of claim 4, wherein the front linkage includes a slidable spreader driver mounted for sliding movement on the load-support frame and a wheel spreader coupled to the slidable spreader driver and arranged to engage a cam provided on each of the left and right front wheel units to move the left and right front wheel units against motion-resisting forces applied to the left and right front wheel units by the spring from the folded storage positions toward the unfolded rolling positions in response to movement of the base pusher about the base-pusher pivot axis away from the stored position toward the 2-wheel hand-truck position to move, in unison, the rear linkage, the slidable spreader driver, and the wheel spreader as a unit toward the front wheels so that the left and right front wheel units are spread apart to cause the front wheels in the left and right front wheel units to rotate about a common axis and on ground underlying the rolling base. 6. The load carrier of claim 1, wherein the load-carrier mode changer means includes a slidable spreader driver mounted for sliding movement on the load-support frame and a wheel spreader coupled to the spreader driver and arranged to engage a cam provided on each of the left and front wheel units and wherein the left and right front wheel units move from the folded storage positions to the unfolded rolling positions during camming engagement with the wheel spreader in response to sliding motion of the slidable spreader driver on the load-support frame toward the front wheels to cause the wheel spreader to move away from the base-pusher pivot axis. 7. The load carrier of claim 6, wherein the wheel spreader includes a proximal portion mounted on the load-support frame for pivotable movement about a spreader-pivot axis and a free portion arranged to pivot about the spreader-pivot axis and engage the cam provided on each of the left and right front wheel units. 8. The load carrier of claim 6, wherein the wheel spreader includes a spreader plate mounted for pivotable movement on the rolling base and a wheel link pivotably coupled to each of the spreader plate and the slidable spreader driver to convert sliding motion of the slidable spreader driver into pivoting motion of spreader plate and wherein the pivoting spreader plate applies a pivot-inducing force to cams included in the left and right front wheel units to pivot the left and right front wheel units from the folded storage positions to the unfolded rolling positions in response to pivoting movement of the base pusher in the first direction about the base-pusher pivot axis to change the load carrier from the flat storage mode to the front-and-rear-wheel cart mode. 9. The load carrier of claim 1, wherein the load-carrier mode changer includes a front linkage coupled to the left and right front wheel units and a rear linkage coupled to the base pusher and mounted for movement on the front linkage between a first position associated with the flat storage mode and the front-and-rear-wheel cart mode of the load carrier and a second position associated with a 2-wheel hand-truck mode of the load carrier, the front and rear linkages cooperate to provide means for pivoting the left and right front wheel units from the folded storage positions to the unfolded rolling positions only when the rear linkage occupies the first position on the front linkage, and the base pusher is arranged to pivot about the base-pusher pivot axis in a direction away from the front wheel units to move relative to the load-support frame of the rolling base from the upright cart position to a laidback hand-truck position to establish a 2-wheel hand-truck mode of the load carrier in response to movement of the rear linkage relative to the front linkage from the first position to the second position. 10. The load carrier of claim 9, wherein the front linkage includes a slidable spreader driver mounted for sliding movement on the load-support frame and a wheel spreader coupled to the slidable spreader driver and arranged to lie in camming engagement with the left and right front wheel units. 11. The load carrier of claim 10, wherein the wheel spreader includes a spreader plate mounted for pivotable movement on the rolling base and a wheel link pivotably coupled to each of the spreader plate and the slidable spreader driver to convert sliding motion of the slidable spreader driver into pivoting motion of spreader plate and wherein the pivoting spreader plate applies a pivot-inducing force to cams included in the left and right front wheel units to pivot the left and right front wheel units from the folded storage positions to the unfolded rolling positions in response to pivoting movement of the base pusher in the first direction about the base-pusher pivot axis. 12. The load carrier of claim 8, wherein the load-support frame and the base pusher cooperate to define therebetween an included angle of about 180° upon movement of the base pusher to the laidback hand-truck position. 13. A collapsible load carrier comprising a rolling base including a load-support frame, a left front wheel unit mounted for pivotable movement on the load-support frame about a left pivot axis between a folded storage position and an unfolded rolling position, a right front wheel unit mounted for pivotable movement on the load-support frame about a right pivot axis between a folded storage position and an unfolded rolling position, and a spring yieldably pivoting each front wheel unit about its pivot axis normally to assume the folded storage position, the folded storage position associated with a flat storage mode of the load carrier in which front wheels in the front wheel units disengage ground underlying the rolling base and a front wheel in the left front wheel unit is arranged to extend toward a front wheel in the right front wheel unit, and the unfolded rolling position associated with a front-and-rear-wheel cart mode of the load carrier in which the front wheels in the front wheel units are arranged to engage and roll on ground underlying the rolling base and rotate about a common axis of rotation,a base pusher mounted for pivotable movement relative to the load-support frame of the rolling base about a base-pusher pivot axis from a stored position arranged to lie alongside and on top of the load-support frame of the rolling base and associated with the flat storage mode of the load carrier in a first direction toward a laidback hand-truck position to cause a rear wheel included in the base pusher to engage and roll on ground underlying the rolling base, anda load-carrier mode changer including a front linkage mounted for sliding movement on the load-support frame and arranged to engage each of the front wheel units in camming relation and a rear linkage coupled to each of the front linkage and the base pusher and arranged to cooperate with the front linkage to apply a camming force to each of the front wheel units in response to pivoting movement of the base pusher about the base-pusher pivot axis in the first direction. 14. The load carrier of claim 13, wherein the front linkage includes a slidable spreader driver mounted for sliding movement on the load-support frame and a wheel spreader coupled to the slidable spreader driver to lie between the slidable spreader driver and the front wheels and arranged to lie in camming engagement with the front wheel units. 15. The load carrier of claim 14, wherein the wheel spreader includes a spreader plate mounted for pivotable movement on the rolling base and a wheel link pivotably coupled to each of the spreader plate and the slidable spreader driver to convert sliding motion of the slidable spreader driver into pivoting motion of spreader plate and wherein the pivoting spreader plate applies a pivot-inducing force to cams included in the left and right front wheel units to pivot the left and right front wheel units from the folded storage positions to the unfolded rolling positions in response to pivoting movement of the base pusher in the first direction about the base-pusher pivot axis. 16. The load carrier of claim 14, wherein the rear linkage is mounted for movement on the front linkage between a first position associated with the flat storage mode and the front-and-rear-wheel cart mode of the load carrier and a second position associated with the 2-wheel hand-truck mode of the load carrier. 17. The load carrier of claim 13, wherein the load-support frame and the base pusher cooperate to define therebetween an included angle of about 180° upon movement of the base pusher to the laidback hand-truck position. 18. A collapsible load carrier comprising a rolling base including a load-support frame, a left front wheel unit mounted for pivotable movement on the load-support frame about a left pivot axis between a folded storage position and an unfolded rolling position, a right front wheel unit mounted for pivotable movement on the load-support frame about a right pivot axis between a folded storage position and an unfolded rolling position, and a spring yieldably pivoting each front wheel unit about its pivot axis normally to assume the folded storage position, the folded storage position associated with a flat storage mode of the load carrier in which front wheels in the front wheel units disengage ground underlying the rolling base and a front wheel in the left front wheel unit is arranged to extend toward a front wheel in the right front wheel unit, and the unfolded rolling position associated with a front-and-rear-wheel cart mode of the load carrier in which the front wheels in the front wheel units are arranged to engage and roll on ground underlying the rolling base and rotate about a common axis of rotation,a base pusher mounted for pivotable movement relative to the load-support frame of the rolling base about a base-pusher pivot axis from a stored position arranged to lie alongside and on top of the load-support frame of the rolling base and associated with the flat storage mode of the load carrier in a first direction toward a laidback hand-truck position to cause a rear wheel included in the base pusher to engage and roll on ground underlying the rolling base, anda spreader plate mounted for pivotable movement on the rolling base, the spreader plate configured to apply a pivot-inducing force to cams included in the left and right front wheel units to pivot the left and right front wheel units from the folded storage positions to the unfolded rolling positions in response to pivoting movement of the base pusher in the first direction about the base-pusher pivot axis. 19. The collapsible load carrier of claim 18, further comprising a slidable spreader driver mounted for sliding movement on the load-support frame and a wheel link pivotably coupled to each of the spreader plate and the slidable spreader driver to convert sliding motion of the slidable spreader driver into pivoting motion of spreader plate. 20. The collapsible load carrier of claim 18, further comprising a pusher link pivotably coupled to the base pusher at a first end and coupled to the slidable spreader for movement therewith along the load-support frame at a second end.