초록

A hand truck includes a base and a toe-plate shelf coupled to the base. The base includes a truck frame and a wheel unit coupled to the truck frame.

대표청구항 ▼

The invention claimed is: 1. A hand truck comprising a rolling base, a toe-plate shelf coupled to the rolling base, an auxiliary carrier including a movable shelf arranged to lie above the toe-plate shelf and a shelf position changer means for changing the position of the movable shelf on the rolli

The invention claimed is: 1. A hand truck comprising a rolling base, a toe-plate shelf coupled to the rolling base, an auxiliary carrier including a movable shelf arranged to lie above the toe-plate shelf and a shelf position changer means for changing the position of the movable shelf on the rolling base relative to the toe-plate shelf underlying the movable shelf to vary the elevation of the movable shelf above the toe-plate shelf, wherein the shelf position changer includes a shelf mover mounted for up-and-down movement on the rolling base and the movable shelf is coupled to the shelf mover to move therewith between a lowered position near the toe-plate shelf and a raised position elevated above the toe-plate shelf, wherein the rolling base includes a truck frame and a wheel unit coupled to the truck frame, the truck frame includes first and second upright rails arranged to lie in spaced-apart relation to one another and rungs arranged to interconnect the first and second upright rails, and the shelf mover includes a first side leg mounted for sliding movement on the first upright rail, a second side leg mounted for sliding movement on the second upright rail, and a crossbar interconnecting the first and second side legs, and the movable shelf is coupled to the first and second side legs to move therewith, and wherein the first upright rail is formed to include an outer channel, the first side leg of the shelf mover includes an inwardly facing surface facing toward the outer channel, and the shelf mover further includes first, second, and third blocks coupled to the inwardly facing surface of the first side leg and arranged to extend into and move in the outer channel during up-and-down movement of the shelf mover on the rolling base to provide guide means for guiding the shelf mover relative to the truck frame as a user lifts, pivots, lowers, and raises the shelf mover to change elevation of movable shelf relative to the toe-plate shelf. 2. The hand truck of claim 1, wherein the movable shelf is arranged to mate with the toe-plate shelf upon movement of the movable shelf on the rolling base to assume the lowered position to establish a rigidified shelf made of the mating movable and toe-plate shelves. 3. The hand truck of claim 1, wherein the shelf position changer further includes anchor means coupled to the shelf mover for engaging more than one of the rungs included in the truck frame to establish an elevation of the movable shelf above the toe-plate shelf underlying the movable shelf. 4. The hand truck of claim 3, wherein the anchor means is coupled to the crossbar to move therewith during movement of the shelf mover relative to the truck frame. 5. The hand truck of claim 3, wherein the anchor means includes a first anchor coupled to the cross bar of the shelf mover and arranged to lie in spaced-apart relation to the first side rail of the shelf mover to define a rail-receiving space therebetween receiving the first guide rail of the rolling base therein during up-and-down movement of the shelf mover on the rolling base. 6. The hand truck of claim 1, wherein the rolling base is formed to include first and second guide surfaces arranged to lie in spaced-apart relation to one another to define an outer channel therebetween and the shelf mover includes a first side leg arranged to extend along the outer channel and guide means coupled to the first side leg and arranged to extend into the outer channel for engaging the first and second guide surfaces during up-and-down movement of the shelf mover on the rolling base to support the shelf position changer for sliding and pivoting motion relative to the rolling base as the elevation of the movable shelf relative to the toe-plate shelf is changed. 7. The hand truck of claim 6, wherein the guide means includes a lower guide block coupled to a lowermost end of the first side leg, an upper guide block coupled to a middle portion of the first side leg, and a middle pivot block coupled to the first side leg and located midway between the upper and lower guide blocks. 8. The hand truck of claim 7, wherein the shelf mover further includes a handle coupled to an upper portion of the first side leg arranged to extend upwardly from the upper guide block in a direction away from the lower guide block and the shelf position changer further includes an anchor coupled to the handle and arranged to mate with the rolling base to fix a position of the movable shelf relative to the toe-plate shelf and to separate from the rolling base during upward movement of the handle away from the toe-plate shelf and pivoting movement of the handle about a fulcrum established by engagement of the middle pivot block and the second guide surface to allow movement of the movable shelf relative to the toe-plate shelf to assume a new elevation. 9. The hand truck of claim 7, wherein the lower guide block is located along a rear edge of the first side leg to mate in sliding engagement with the first guide surface of the rolling base during up-and-down movement of the shelf mover relative to the rolling base and the upper guide block is located along an opposite front edge of the first side leg to mate in sliding engagement with the second guide surface of the rolling base during up-and-down movement of the shelf mover relative to the rolling base. 10. The hand truck of claim 9, wherein the upper guide block is moved in the outer channel to mate with the second guide surface and the lower guide block is moved in the outer channel to mate with the first guide surface in response to pivoting movement of the shelf position changer about a fulcrum established by engagement of the middle pivot block with the second guide surface. 11. The hand truck of claim 6, wherein the rolling base includes a first upright rail formed to include the first and second guide surfaces and the outer channel and the first side leg is arranged to move along the first upright rail during up-and-down movement of the shelf position changer on the rolling base. 12. A hand truck comprising a rolling base, a toe-plate shelf coupled to the rolling base, an auxiliary carrier including a movable shelf arranged to lie above the toe-plate shelf and a shelf position changer means for changing the position of the movable shelf on the rolling base relative to the toe-plate shelf underlying the movable shelf to vary the elevation of the movable shelf above the toe-plate shelf, and wherein the rolling base includes a series of vertically spaced-apart rungs and the shelf position changer further includes anchor means for engaging more than one of the rungs to establish an elevation of the movable shelf above the toe-plate shelf underlying the movable shelf. 13. The hand truck of claim 12, wherein the shelf position changer further includes a shelf mover mounted on the rolling base for up-and-down movement relative to the rungs and arranged to interconnect the movable shelf and the anchor means, the shelf mover includes a handle adapted to be gripped by a user to control the location of the shelf mover relative to the rungs, and the anchor means is coupled to the handle. 14. The hand truck of claim 12, wherein the anchor means includes a hook configured to mate with each of the rungs. 15. A hand truck comprising a rolling base, a toe-plate shelf coupled to the rolling base, an auxiliary carrier mounted on the rolling base for movement relative to the toe-plate shelf, wherein the auxiliary carrier includes a movable shelf, a shelf mover, and an anchor coupled to the shelf mover, the movable shelf is coupled to the shelf mover to move up and down with the shelf mover on the rolling base and relative to the toe-plate shelf underlying the movable shelf, and the anchor is configured to mate with the rolling base to limit the movement of the shelf mover and the movable base relative to the rolling base and to separate from the rolling base in response to movement of the shelf mover away from the toe-plate shelf to change the position of the movable shelf on the rolling base so as to vary the elevation of the movable shelf relative to the toe-plate shelf underlying the movable shelf and wherein the rolling base includes a truck frame and a wheel unit coupled to the truck frame, the truck frame includes first and second upright rails arranged to lie in spaced-apart relation to one another and rungs arranged to interconnect the first and second upright rails, and the shelf mover includes a first side leg mounted for sliding movement on the first upright rail, a second side leg mounted for sliding movement on the second upright rail, and a crossbar interconnecting the first and second side legs, and the movable shelf is coupled to the first and second side legs to move therewith. 16. The hand truck of claim 15, wherein the movable shelf is arranged to mate with the toe-plate shelf upon movement of the movable shelf on the rolling base to assume a lowered position to establish a rigidified shelf made of the mating movable and toe-plate shelves. 17. A hand truck comprising a rolling base, a toe-plate shelf coupled to the rolling base, and an auxiliary carrier including a movable shelf arranged to lie above the toe-plate shelf and a shelf position changer means for changing the position of the movable shelf on the rolling base relative to the toe-plate shelf underlying the movable shelf to vary the elevation of the movable shelf above the toe-plate shelf, wherein the shelf position changer includes a shelf mover mounted for up-and-down movement on the rolling base and the movable shelf is coupled to the shelf mover to move therewith between a lowered position near the toe-plate shelf and a raised position elevated above the toe-plate shelf, wherein the rolling base includes a truck frame and a wheel unit coupled to the truck frame, the truck frame includes first and second upright rails arranged to lie in spaced-apart relation to one another and rungs arranged to interconnect the first and second upright rails, and the shelf mover includes a first side leg mounted for sliding movement on the first upright rail, a second side leg mounted for sliding movement on the second upright rail, and a crossbar interconnecting the first and second side legs, and the movable shelf is coupled to the first and second side legs to move therewith, and wherein the shelf position changer further includes anchor means coupled to the shelf mover for engaging more than one of the rungs included in the truck frame to establish an elevation of the movable shelf above the toe-plate shelf underlying the movable shelf. 18. A hand truck comprising a rolling base, a toe-plate shelf coupled to the rolling base, and an auxiliary carrier including a movable shelf arranged to lie above the toe-plate shelf and a shelf position changer means for changing the position of the movable shelf on the rolling base relative to the toe-plate shelf underlying the movable shelf to vary the elevation of the movable shelf above the toe-plate shelf, wherein the shelf position changer includes a shelf mover mounted for up-and-down movement on the rolling base and the movable shelf is coupled to the shelf mover to move therewith between a lowered position near the toe-plate shelf and a raised position elevated above the toe-plate shelf, wherein the rolling base is formed to include first and second guide surfaces arranged to lie in spaced-apart relation to one another to define an outer channel therebetween and the shelf mover includes a first side leg arranged to extend along the outer channel and guide means coupled to the first side leg and arranged to extend into the outer channel for engaging the first and second guide surfaces during up-and-down movement of the shelf mover on the rolling base to support the shelf position changer for sliding and pivoting motion relative to the rolling base as the elevation of the movable shelf relative to the toe-plate shelf is changed, and wherein the guide means includes a lower guide block coupled to a lowermost end of the first side leg, an upper guide block coupled to a middle portion of the first side leg, and a middle pivot block coupled to the first side leg and located midway between the upper and lower guide blocks.