Crossing with thermal expansion joint for a rail-based grid

A storage system comprising a framework structure, the framework structure comprising:

• upright members and a two-dimensional rail system arranged across the top of the upright members,
• wherein the rail system comprises:
• a first set of parallel rails arranged to guide movement of container handling vehicles in a first direction across the top of the frame structure, and
• a second set of parallel rails arranged perpendicular to the first set of rails to guide movement of the container handling vehicles in a second direction which is perpendicular to the first direction,
• the first and second sets of parallel rails dividing the rail system into a plurality of access openings in the rail system for lifting and lowering of a storage container between a position above the rail system and a position below the rail system, and
• wherein the storage system comprises at least one crossing arranged along each rail of the first or second set of parallel rails forming a continuous track from one end of the rail system to an opposite end of the rail system,
• wherein the crossing comprises:
• a first rail extending in a first direction, and
• a second rail extending in a second direction which is perpendicular to the first direction,
• wherein the first and second rails each comprise at least one track for guiding wheels of a container handling vehicle in a longitudinal direction of said rail, the first and second rails engaging one another to form the crossing where the at least one track of the first rail crosses a path of the at least one track of the second rail, the crossing being configured to be supported by an upright member from below, and
• wherein at least one of the first and second rails is provided as a pair of rail sections arranged in an end-to-end manner in the longitudinal direction of said rail, the ends of the rail sections meeting in a central portion of the crossing, and the rail sections being configured to permit a range of movement of one end relative to the other in the longitudinal direction of the said rail so as to provide a thermal expansion joint for the said rail that is arranged within a volume of the crossing defined by the engagement of the first and second rails.

A method of providing a crossing in a grid-based rail system of an automated storage and retrieval system, the crossing allowing for thermal expansion and contraction of rails extending through the crossing;

• the method comprises:
• positioning a pair of rail sections of a first rail extending in a first direction and a second rail extending in a second direction on an underlying supporting upright member, wherein the second direction is perpendicular to the first direction and wherein the first and second rails each comprise at least one track for guiding wheels of a container handling vehicle in a longitudinal direction of said rail;
• wherein the first and second rails engage to form the crossing;
• where at least one track of the first rail crosses a path of the at least one track of the second rail, the rail sections being arranged in an end-to-end manner in a longitudinal direction of a rail and the ends of the rail sections meeting in a central portion of the crossing to permit a range of movement of one end relative to the other in the longitudinal direction of the first or second rail, thereby providing a thermal expansion joint for the first or second rail that is arranged within the crossing within a volume defined by the engagement of the first and second rails.