Apparatus for retrieving units from a storage system
A storage system and a load handling device for lifting and moving containers stacked in the storage system are described. The storage system includes a plurality of rails or tracks arranged in a grid pattern above the stacks of containers. The grid pattern can include a plurality of grid spaces and each stack is located within a footprint of only a single grid space. The load handling device is configured to move laterally on the rails or tracks above the stacks. The load-handling device includes a container-receiving space located above the rails or tracks in use and a lifting device arranged to lift a container from a stack into the container-receiving space. The load handling device has a footprint that, in use, occupies only a single grid space in the storage system.
1. A storage system comprising:
a first set of parallel rails or tracks and a second set of parallel rails or tracks extending transverse to the first set in a substantially horizontal plane to form a grid pattern including plural grid spaces;
a framework for defining columns beneath the plural grid spaces for retaining plural stacks of containers located beneath the rails, and configured such that each stack will be located within a footprint of a single grid space; and
a load handling device configured to move laterally above the columns on the rails, the load handling device including a container-receiving space located above the rails and a lifting device arranged to lift a single container from a respective column into the container-receiving space;
wherein the load handling device includes an external housing that substantially encloses the container-receiving space;
wherein the load handling device is configured to move in a first direction along the first set of parallel rails or tracks and in a second direction along the second set of parallel rails or tracks;
wherein the load handling device includes a wheel assembly having a first set of wheels for engaging with the first set of parallel rails or tracks to guide movement of the device in the first direction and a second set of wheels for engaging with the second set of parallel rails or tracks to guide movement of the device in the second direction;
wherein the wheels are arranged around a periphery of the container-receiving space; and
wherein the external housing extends no further than the wheels such that the load handling device has a footprint that occupies only a single grid space in the storage system.
2. A storage system according to claim 1 , wherein the lifting device comprises:
a gripper device configured to grip a container from above the grid spaces.
3. A storage system according to claim 2 , wherein the load handling device comprises:
a lifting mechanism configured to raise and lower the gripper device relative to the container-receiving space.
4. A storage system according to claim 1 , wherein each load handling device comprises:
means for selectively engaging and disengaging the first set of wheels with the first set of parallel rails; and
means for selectively engaging and disengaging the second set of wheels with the second set of parallel rails.
5. A load handling device, comprising:
a container-receiving space configured to accommodate a container;
an external housing that substantially encloses the container-receiving space; and
a wheel assembly having a first set of wheels to be engaged with a first set of parallel rails or tracks of a storage system to guide movement of the device in a first direction and a second set of wheels to be engaged with a second set of parallel rails or tracks of the storage system to guide movement of the device in a second direction,
wherein the first and second sets of wheels are arranged around a periphery of the container-receiving space and on an outer surface of the housing, and
wherein the external housing extends no further than the wheels such that the load handling device has a footprint that occupies only a single grid space in the storage system.
6. A load handling device according to claim 5 in combination with a storage system, the storage system comprising:
a first set of parallel rails or tracks and a second set of parallel rails or tracks extending transverse to the first set in a substantially horizontal plane to form a grid pattern including plural grid spaces; and
a framework for defining columns beneath the plural grid spaces for retaining plural stacks of containers located beneath the rails, and configured such that each stack will be located within a footprint of a single grid space.
7. The load handling device according to claim 6 , comprising:
a lifting device configured to lift a container from a stack into the container receiving space,
wherein the load handling device is configured to move in a first direction along the first set of parallel rails or tracks and in a second direction along the second set of parallel rails or tracks, wherein the second direction is transverse to the first direction.
8. The load handling device of claim 6 , wherein the housing is shaped substantially in a cuboid.
9. The load handling device according to claim 5 , comprising:
an upper part housing at least power components, control components, drive components and/or lifting components, and a lower part including the container-receiving space, wherein the lower part is arranged directly beneath the upper part.