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.
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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 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 an 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, and a spring yieldably pivoting each front wheel unit about its pivot axis normally to assume the folded storage position,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 to an upright cart position to cause a rear wheel included in the base pusher to engage and roll on ground underlying the rolling base, 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 through a first pivot angle to the upright cart position to cause the rear wheel included in the base pusher to engage and roll on ground underlying the rolling base to establish a front-and-rear-wheel cart mode of the load carrier. 2. The load carrier of claim 1, wherein the base pusher is also movable about the base-pusher pivot axis from the stored position in the first direction past the upright cart position to reach a 2-wheel hand-truck position to lie in generally coplanar relation to the top of the load-support frame of the rolling base to define an included angle of about 180° therebetween to establish a 2-wheel hand-truck mode of the load carrier in which the rolling base is supported for rolling movement only on the front wheels upon movement of the rolling base and the base pusher as a unit to disengage any rear wheel in the base pusher from the ground underlying the rolling base. 3. The load carrier of claim 2, wherein the load-carrier mode changer means includes a front linkage coupled to the left and right front wheel units and mounted for sliding movement on the load-support frame of the rolling base 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 and the base pusher is configured to pivot about the base-pusher pivot axis in the first direction from the upright cart position to the 2-wheel hand-truck position while the front linkage remains in a stationary position on the load-support frame of the rolling base during movement of the rear linkage relative to the front linkage from the first position to the second position to establish the 2-wheel hand-truck mode of the load carrier. 4. The load carrier of claim 3, 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 to the unfolded rolling positions in response to movement of the base pusher about the base-pusher pivot axis in the first direction 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. 5. The load carrier of claim 4, wherein the rear linkage includes a pusher rotator mounted for movement on the slidable spreader driver of the front linkage between the first and second positions and a push rod coupled to the pusher rotator and to the base pusher to cooperate with the pusher rotator while the pusher rotator remains in the first position to convert pivoting motion of the base pusher about the base-pusher pivot axis into sliding motion of the slidable spreader driver on the load-support frame in a direction toward the front wheels to urge the wheel spreader into camming engagement with the left and right front wheel units to move those wheel units from their folded storage positions to their unfolded rolling positions. 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 7, 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 through a second pivot angle 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 and the rear linkage includes a pusher rotator mounted for movement on the slidable spreader driver between the first and second positions and a push rod coupled to the pusher rotator and to the base pusher. 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 to change the load carrier from the flat storage mode to the front-and-rear-wheel cart mode. 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 90° upon movement of the base pusher to the upright cart position and 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. The load carrier of claim 8, wherein each of the first and second pivot angles is about 90°. 14. 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 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 an 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, and a spring yieldably pivoting each front wheel unit about its pivot axis normally to assume the folded storage position,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 to an upright cart 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 when the load carrier is in the flat storage mode to move each of the front wheel units from the folded storage position to the unfolded rolling position to establish the front-and-rear-wheel cart mode of the load carrier. 15. The load carrier of claim 14, 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. 16. The load carrier of claim 15, 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. 17. The load carrier of claim 15, 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, 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 the first direction 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 n response to movement of the rear linkage relative to the front linkage from the first position to the second position. 18. The load carrier of claim 17, wherein the rear linkage includes a pusher rotator mounted for movement on the front linkage between the first and second positions and a push rod pivotably coupled to each of the pusher rotator and the base pusher. 19. The load carrier of claim 18, wherein the pusher rotator is mounted on the front linkage for pivotable movement about a rotator pivot axis between the first and second positions. 20. The load carrier of claim 17, 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 and the rear linkage includes a pusher rotator mounted for movement on the slidable spreader driver between the first and second positions and a push rod coupled to the pusher rotator and to the base pusher. 21. The load carrier of claim 1, wherein the base pusher includes a push handle and an outrigger wheel unit coupled to the push handle to move therewith and configured to include the rear wheel. 22. The load carrier of claim 21, wherein each of the left and right front wheels has a first diameter and the rear wheel has a second diameter that is less than the first diameter. 23. The load carrier of claim 22, wherein the second diameter is about half of the first diameter. 24. The load carrier of claim 21, wherein the outrigger wheel unit includes a horizontally extending wheel support coupled to the push handle to move therewith relative to the rolling base during pivotable movement of the base pusher about the base-pusher pivot axis and the rear wheel is coupled to the horizontally extending wheel support to move therewith. 25. The load carrier of claim 21, wherein the outrigger wheel unit includes a first caster including the rear wheel, a second caster including a second rear wheel, and a caster-support rail arranged to interconnect the first and second casters and coupled to the push handle to move therewith. 26. The load carrier of claim 25, wherein the push handle includes a leg mounted on the load-support frame for pivotable movement about the base-pusher pivot axis, the leg includes an upper portion above the base pusher axis and a lower portion below the base-pusher axis, and the caster-support rail is coupled to the lower portion of the leg of the push handle. 27. The load carrier of claim 26, wherein the base pusher is also movable about the base-pusher pivot axis from the stored position in the first direction past the upright cart position to reach a 2-wheel hand-truck position to lie in generally coplanar relation to the top of the load-support frame of the rolling base to define an included angle of about 180° therebetween to establish a 2-wheel hand-truck mode of the load carrier in which the rolling base is supported for rolling movement only on the front wheels upon movement of the rolling base and the base pusher as a unit to disengage any rear wheel in the base pusher from the ground underlying the rolling base and wherein the load-carrier mode changer means includes a front linkage coupled to the left and right front wheel units and mounted for sliding movement on the load-support frame of the rolling base and a rear linkage coupled to the lower portion of the leg of the push handle of 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 and the base pusher is configured to pivot about the base-pusher pivot axis in the first direction from the upright cart position to the 2-wheel hand-truck position while the front linkage remains in a stationary position on the load-support frame of the rolling base during movement of the rear linkage relative to the front linkage from the first position to the second position to establish the 2-wheel hand-truck mode of the load carrier.
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이 특허에 인용된 특허 (27)
Meier James W., Brake and retractable rear stabilizer apparatus for a hand dolly.
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