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Crane Classification “C”: This CMAA service rating covers cranes where operation requirements are moderate. In this type of service the crane will handle loads which average 50 percent of rated capacity with 5 to 10 lifts per hour. These lifts will average 15 feet, not over 50 percent of the lift at rated capacity. All Rapistak Corporation stackers are Class “C” rated unless otherwise specified.

CMAA (Crane Manufacturer’s Association of America): CMAA is an organization of leading electric overhead traveling crane manufacturers in the United States, for the purpose of promoting standardization and providing a basis for equipment classification. The CMAA is an independent incorporated trade association affiliated with The United States Division of Material Handling Industry (MHI).

Bridge Assembly:  The bridge travels the full length of the rack on a runway. The bridge wheels ride on rail attached to the top of the rack. The bridge can be manually operated or motorized.

Trolley Assembly: The trolley rides on top of the bridge assembly and travels back and forth the width of the system aisle. The trolley can be manually operated or motorized.

Mast Assembly: The mast is bolted to the underside of the trolley via a rotation bearing. This allows for 360 degree continuous rotation. The mast hangs down to within a few inches of the floor. An adjustable toe guard mounted to the base of the mast allows you to adjust the minimum clearance between the bottom of the mast and the floor. Thus preventing operator injury from his/her foot getting caught beneath the mast during operation. Rotation of the mast can be manually operated or motorized.

Hoist Assembly: The hoist is located at the top of the mast assembly. It is used for lifting and lowering of the carriage. A chain hoist is typically used. The hoist assembly is ALWAYS motorized.

Manual Operation: Refers to a specific direction of travel which requires a person to apply force in order to move. This can be for the bridge, trolley or rotation motion on the stacker crane.

Motorized Operation: Refers to a specific direction of travel which utilizes a motor. It does not require a person to apply force in order to move. This can be for the bridge, trolley or rotation motion. The hoist motion is always motorized.

Carriage/Fork Assembly: The carriage assembly is located inside the mast assembly. The forks are attached to the carriage assembly. The hoist is used to lift and lower the carriage/fork assembly. The forks are used to handle the product and/or pallet.

Freefall Safety Device: A safety mechanism integrated with the carriage/fork assembly. In case of slack or broken chain the free fall device engages the inside of the mast assembly to prevent the load from falling to the ground. Thus preventing product damage and operator injury.

Mast Back Stop: An adjustable guard mounted to the top of the mast assembly. This guard strikes against a backstop beam on the rack to prevent the operator from pinning themselves between the mast and rack while backing up.

VFC: Variable Frequency Drives (VFC) are used to electronically control the speeds of a given function. This allows the operator to use the equipment at a speed which is most efficient and safe while having the ability to run the equipment at maximum speed. Use of VFC technology also prevents premature component failure associated with hard starts and stops of the equipment, common with older contactor controls. This is accomplished through a ramp up and ramp down feature used to control the acceleration and deceleration of a given function. All motorized functions come standard with VFC control EXCEPT the hoist.

Upright Frame: Vertical weldment which is pre-assembled at the factory. Two of these vertical upright frames comprise one section of racking.

Rack Section:  A section is one standing unit. It is comprised of two upright frames and stands on one side of an aisle. Two or more sections standing side by side make up a row of rack.

Bay: One bay of rack consists of two sections on opposing sides of the aisle facing one another.   I.E.   7-bay single aisle PROSTAK contains (7) sections of racking on the right side of the aisle and (7) sections of racking on the left side of the aisle. Therefore there are (14) total sections in a (7) bay single aisle system, and the system consists of two rows of racking. 

Vertical/Top X-Brace: X-brace panels are bolted to the top of each section. Depending on the height, an X-brace panel may be added at the mid point vertically of a section. These help prevent buckling and add to the rigidity of the section. Thus providing smoother operation through minimizing movement from down aisle and cross aisle forces created by the crane travel.

Horizontal X-Brace: X-Brace panels bolted to the rear of a section. Typically (3) panels per section are used. These help prevent buckling and add to the rigidity of the section. Thus providing smoother operation through minimizing movement from down aisle and cross aisle forces created by the crane travel.

Pallet: The pallet is the load carrying component of the rack. On PROSTAK systems the pallet not only serves as the product handling component outside of the system but acts as the shelf inside the rack. These pallets are removable and adjustable in 4” increments and allow for high density storage through the best possible use of space available. They are available in a variety of standard sizes.

ASCE Rail: The rail is mounted on top of the rack and is what the bridge travels on. Commonly called the runway. Rail can be mounted directly to the top of the uprights or may be mounted to a structural wide flange beam called the runway support beam which is then mounted to the upright frame. Standard rail used is 30# ASCE rail.

Conductor Bar: Power to the system is provided through the conductor bar. There are 4 bars used, three for power and one for ground. The bar is mounted to the top of the upright frames and run the length of the system.

Runout: A run out is a section of runway that extends past the last bay of racking. A run out is typically used for product transfer outside of the racking. Run outs can be small or large depending on the requirement. A typical run out is 3-4 feet which requires no additional supports. As the run out length increases, additional supports in the form of columns will be needed.

Crossover: Crossovers are used on double and triple aisle systems. A crossover allows the stacker crane to move from one aisle to another. Crossovers can be strategically placed in the system in several combinations. One option is to place the crossover at or near the center of the system. A second option is to place the crossover at only one end of the system. A third option is to place crossovers on both ends of the system. Yet another option is to use a crossover in the center as well as at one end of the system. And finally you can use a crossover at both ends of the system as well as in the center. One or more sections are removed from the center rows of racking allowing access to the second or third aisle of a system. Commonly used on larger systems this improves cycle time and increases the productivity of the system.

Access Aisle: An access aisle can be used on single or multiple aisle systems. One or more sections are removed from the outside row of rack. This allows for product drop off and pick-up from a secondary point in the system. Access aisles can also be used for through traffic such as fork lifts or other in plant vehicles.