Lifting assembly

A container lifting assembly for raising and/or lowering containers stacked in stacks in a grid storage structure, the lifting assembly comprising:

• a gripping device configured to releasably grip a container;
• a raising and lowering mechanism configured to raise and lower the gripping device, wherein the raising and lowering mechanism includes:
• a first shaft, a second shaft, a first spool and a second spool on the first shaft, and a third spool and a fourth spool on the second shaft;
• a first tether, a second tether, a third tether, and a fourth tether configured to wind and unwind from the first, second, third, and fourth spools respectively, wherein the first, second, third, and fourth tethers are connected to the gripping device, wherein the first and second spools are configured to rotate in an opposite direction to the third and fourth spools to wind and unwind the first, second, third, and fourth tethers to raise and lower the gripping device;
• a timing belt;
• a motor;
• and
• first and second pulleys on the first and second shafts respectively, the first and second pulleys being arranged to be driven by the motor in opposite directions via the timing belt;
• and
• wherein the first, second, third, and fourth tethers are configured such that a point at which each tether winds and unwinds to or from a respective spool is at or near a respective corner of the container lifting assembly.

A method of raising and/or lowering a container from a stack of containers, in a grid storage structure including a plurality of tracks arranged to form a grid having a grid pattern above the stacks of containers, and with a load handling device which incudes:

• a body housing a driving mechanism operatively arranged for moving the load handling device on the grid;
• and a container lifting assembly including:
• a gripping device configured to releasably grip a container;
• a raising and lowering mechanism configured to raise and lower the gripping device, wherein the raising and lowering mechanism includes:
• a first shaft, a second shaft, a first spool and a second spool on the first shaft, and a third spool and a fourth spool on the second shaft;
• a first tether, a second tether, a third tether, and a fourth tether configured to wind and unwind from the first, second, third, and fourth spools respectively, wherein the first, second, third, and fourth tethers are connected to the gripping device, wherein the first and second spools are configured to rotate in an opposite direction to the third and fourth spools to wind and unwind the first, second, third, and fourth tethers to raise and lower the gripping device;
• a timing belt;
• a motor;
• and
• first and second pulleys on the first and second shafts respectively, the first and second pulleys being arranged to be driven by the motor in opposite directions via the timing belt;
• and
• wherein the first, second, third, and fourth tethers are configured such that a point at which each tether winds and unwinds to or from a respective spool is at or near a respective corner of the container lifting assembly,
• the container lifting assembly being configured to raise and lower the gripping device relative to the body and for raising and lowering containers stacked in stacks;
• the method comprising the steps of:
• actuating the motor so as to unwind the at least one of the tethers and lower the gripping device relative to the body;
• actuating the gripping device to grip a container;
• and
• actuating the motor so as to wind at least one of the tethers and raise the gripping device relative to the body.