Narrow Aisle Stacker CraneAbstract:A narrow aisle stacker crane is provided, which includes a base unit capable of traveling along aisles in a warehouse and a mast structure that is connected to the base unit. The mast structure may have a height greater than approximately 10 m. A hoisting carriage for an operator, with an attached load carrying platform, is included and is arranged to travel vertically along the mast. The base unit, the hoisting carriage and the load-carrying platform are sized to travel along warehouse aisles of 0.9 m to 1 m in width. The velocity of the base unit in a horizontal direction may be between 1 m is to 5 m/s. The velocity of the hoisting carriage and load-carrying platform in the vertical direction may be less than 1.5 m/s. Horizontal movement of the base unit and vertical movement of the hoisting carriage and load-carrying platform may take place at the same time, so that fast item placement and retrieval can take place despite relatively low movement speeds.Description:FIELD OF THE INVENTIONThis invention relates to lifting or stacker cranes. More particularly, this invention relates to a narrow aisle stacker crane for use in a warehousing system.BACKGROUNDTraditional warehousing systems involve the use of large, single-storey warehouses having wide aisles that are placed between storage areas, such as shelving, to provide passages for fork-lift trucks or other goods conveyancing equipment. However, high land costs have meant that traditional single-storey warehouse models are not cost-effective in many instances. Various other drawbacks exist.It is desirable to provide a system of operating a warehouse facility to achieve a greater space efficiency than is currently achievable. Ideally, the warehouse facility should include narrow aisles that are placed between storage areas. The storage areas should be built to a greater height than current systems in order to maximize storage space on the same footprint of land.Many systems for improving storage efficiency have been proposed. However, a need still exists for stacker cranes that enable warehouses to be constructed with space efficient designs having narrow aisles between storage areas.SUMMARY OF THE INVENTIONVarious aspects of the invention overcome at least some of these and other drawbacks of existing systems. According to one arrangement, the invention provides a stacker crane for use in warehouses, among other facilities. The stacker crane includes a base unit that is capable of traveling between aisles in a warehouse. According to one arrangement of the invention, the base unit may includes a transport mechanism, such as wheels. According to another arrangement of the invention, the base unit may be configured to run along a rail system.According to one arrangement, the base unit may be coupled to a mast structure that ascends upward to enable access to storage areas, such as shelving, in a warehouse environment. According to one arrangement, the mast structure may ascend to a height greater than 10 m. The mast structure may be moveably supported at an upper end by a guiding rail system or other supporting system.According to one arrangement of the invention, a hoisting carriage may be provided that travels vertically along the mast structure. According to another arrangement of the invention, the hoisting carriage may be provided to travel horizontally relative to the mast structure. According to another arrangement of the invention, the hoisting carriage may be configured to include a load-carrying platform that receives palletized goods, containers of goods, loose goods and/or other load configurations from the storage areas of the warehouse environment.According to one arrangement of the invention, the hoisting carriage may be configured to carry an operator thereon. According to one arrangement of the invention, operator controls may be included in the hoisting carriage. According to another arrangement of the invention, the operator controls may include a contact pad that is engaged by the operator's back, such that the crane will not operate unless the operator is seated.According to one arrangement of the invention, at least one motor may be provided to impart motive forces to the hoisting carriage and the base unit. According to one arrangement of the invention, the base unit, the hoisting carriage and the load-carrying platform may be sized to travel along aisles having widths of approximately 0.8 m to approximately 1.3 m. According to another arrangement of the invention, the base unit may be imparted with a horizontal velocity for moving the narrow aisle crane across a floor at approximately 1 m/s to approximately 5 m/s. According to one arrangement, the horizontal velocity may be provided along a direction that is substantially horizontal relative to the floor. According to one arrangement of the invention, the hoisting carriage and load-carrying platform may be imparted with a vertical velocity for moving the hoisting carriage and load-carrying platform along the mast structure at less than approximately 1.5 m/s. According to one arrangement of the invention, the vertical velocity may be provided along a direction that is substantially vertical relative to the floor.According to one arrangement of the invention, the movement of the base unit in the substantially horizontal direction may proceed concurrently with the movement of the hoisting carriage and the load-carrying platform in the substantially vertical direction. The resultant concurrent movement of the hoisting carriage and the load-carrying platform in the horizontal and vertical directions relative to the floor increases the speed of arrival to the designated location, despite the relatively slow individual velocities of the base unit in the horizontal direction and the hoisting carriage and the load-carrying platform in the vertical direction.According to another arrangement of the invention, the base unit may be designed with a horizontal velocity of approximately 1.5 m/s to approximately 3 m/s. According to another arrangement of the invention, the hoisting carriage and load-carrying platform may be designed to include a vertical velocity of approximately 0.25 m/s to approximately 0.75 m/s. According to another arrangement of the invention, the mast height may be greater than approximately 15 m. According to yet another arrangement of the invention, the mast height may be approximately 19 m to approximately 25 m.According to one arrangement of the invention, the base unit may be arranged such that, when completely lowered, the height of the load-carrying platform relative to the floor level is less than approximately 0.75 m. According to another arrangement of the invention, the base unit may be arranged such that, when completely lowered, the height of the load-carrying platform relative to the floor level is between approximately 0.3 m to approximately 0.7 m. According to yet another arrangement of the invention, the base unit may be arranged such that, when completely lowered, the height of the load-carrying platform relative to the floor level is approximately 0.45 m.According to another arrangement of the invention, the mast structure may include a width of approximately 0.6 m to approximately 0.9 m. According to another arrangement of the invention, the mast structure may be configured to support a weight limit for the hoisting carriage and load-carrying platform of approximately 350 kg to approximately 650 kg. According to another arrangement of the invention, the carriage and the load-carrying platform may be sized to travel along warehouse aisles having widths of approximately 0.9 m to approximately 1 m.According to one arrangement of the invention, a transfer structure may be provided for receiving the stacker crane assembly. According to one arrangement of the invention, the transfer structure may include a rail system for guiding the stacker crane assembly onto the transfer structure. In another arrangement, of the invention, the transfer structure may include a vertical support structure that engages the mast structure of the stacker crane. In another arrangement of the invention, the transfer structure may include a transport mechanism that enables the transfer structure to transport the stacker crane between two or more aisles. In another arrangement of the invention, the transfer structure may transport the stacker crane along a path that is substantially perpendicular between the starting aisle rail and the destination aisle rail. In another arrangement of the invention, the transfer structure may transport the stacker crane along a path that is curvilinear between the starting aisle rail and the destination aisle rail.These and other aspects and features of the invention will become apparent upon review of the enclosed drawings and detailed description below. It is also to be understood that both the foregoing general description and the following detailed description are exemplary and not restrictive to the scope of the invention. Numerous other objects, features, and advantages of the invention should become apparent upon a reading of the following detailed description of which is included below.BRIEF DESCRIPTION OF THE DRAWINGSThe accompanying drawings, which are incorporated in and form a part of the specification, illustrate embodiments of the presently disclosed invention and, together with the description, discloses the principles of the invention.ConclusionThe base unit 120 may run on a rail system that is installed along the various aisles, and may be recessed below the floor level. According to one embodiment of the invention, the rail system may be raised above the floor level. According to one arrangement, transfer car running rails may be provided between adjacent rows having rails. The transfer car running rails can be provided to accommodate a transfer car and allow movement between the aisle rails, and may be provided in a perpendicular orientation relative to the rails of adjacent rows. Alternatively, the transfer car running rails may be provided in a non-perpendicular orientations relative to the rails of adjacent rows. One of ordinary skill in the art will readily appreciate that various orientations between the transfer car running rails and the rails of adjacent rows may be employed.The low weight-capacity stacker crane 100 of the present invention, which operates at relatively low speeds can ensure that the rail system may be substantially lighter than those used in conventional stacker crane installations.According to one arrangement of the invention, an upper guiding rail may be provided to engage an upper portion of the mast structure 130 at guiding rollers 325. The upper guiding rail may include a “T” shaped profile, and/or may be affixed to rack portal beams that are provided in a roof portion of a warehouse or other structure.In order to use multiple aisles of a warehouse, either dedicated stacker cranes may be provided, one for each aisle, or the stacker crane must have the ability to move between aisles of the warehouse. There are two main methods of enabling a crane to move between aisles of a warehouse, which are to use a curved rail at the end of an aisle, or to use transfer cars which provide a base into which the crane drives at the end of an aisle. The transfer car can move on rails which extend along the ends of the aisles to align the crane with a rail extending along the length of the adjacent aisle. The crane may then exit the transfer car and move along the new warehouse aisle. There are different ways of achieving appropriate transfer car usage, including a dedicated transfer car for each crane in a warehouse, and a single transfer car for each end of a warehouse that may be called for when needed by an operator. Any of these and other suitable solutions may be employed for moving the stacker crane of the present invention between warehouse aisles, depending on the particular application.The foregoing is provided for purposes of illustrating, explaining, and describing embodiments of this invention. Modifications and adaptations to these embodiments will be apparent to those skilled in the art and may be made without departing from the scope or spirit of this invention. It will be apparent to those skilled in the art that other components performing the same function may be suitably substituted. The scope of the invention is determined solely by the appended claims.