Achieving high-bay efficiency with aisle-changing cranes

The latest technology in aisle-changing automated storage and retrieval cranes provide significant advantages compared to using dedicated-aisle cranes in high-bay warehouses.

TO REMAIN competitive in the modern warehousing environment, distribution centres require systems that offer the flexibility to adjust quickly and accurately to market conditions, such as meeting shortened lead times. 

The most streamlined warehouses today are highly automated facilities, with maximised high-bay, high-density storage that utilises automated storage and retrieval systems (ASRS). Central to the ASRS is its stacker cranes which permit full-pallet load and layered-pallet inventory to be moved quickly, safely and precisely within a high-bay warehouse environment. 

 Efficient, flexible design

Modern cranes operate within a set of top and bottom rails, eliminating the need for any flat-floor requirements. Since the crane is stabilised by the rail connections, greater load capacities are available, as well as higher rack heights, when compared to free roaming lift trucks. ASRS cranes have a high efficiency of cycle time, a calculation of the movement of product within a DC's storage system.

Many manual operations in a warehouse transport product in only one direction, then return with an empty load. Stacker cranes place a load into a rack position, and then retrieve a load from storage on their way back out, optimising the crane's movements. This helps to reduce operating and distribution costs in the warehouse, including the number of people required to operate the warehouse, thus allowing DC's to operate at a more cost-efficient level.

The latest generation of cranes incorporate a unique flexibility, allowing single-deep, double-deep, triple-deep and up to 20-deep pallet stacking utilising telescopic forks and shuttle cars, with the flexibility to handle one load at a time or multiple loads. 

High-speed PLCs with integrated controls architecture monitor the movements of the cranes. Receiving directions from the distribution center's warehouse management system (WMS) and warehouse control system (WCS) via Ethernet, the cranes utilise barcode technology to direct their movement in the high-bay and the crane's movement of pallets.

The most efficient stacker cranes that provide the lowest operating cost per hour are now fully A/C powered. This eliminates the costs associated with DC batteries, charging, and associated maintenance. Such cranes have also eliminated hydraulics, which greatly reduces maintenance costs.
Although aisle-changing capability in stacker cranes has been around in some form since the early 1990's, the speed and efficiency with which these new cranes can now execute aisle changes makes them a serious option for use in any DC interested in reducing operational costs while improving throughput.

Reducing costs

Most high-rise warehouses use ASRS cranes that are only capable of travelling in a straight line, in one aisle. The limitation of such a dedicated-aisle crane is that one crane is required to service each storage aisle in a warehouse. 

As cranes are a major part of the cost of high-bay warehouse solutions, by reducing the numbers of cranes significant savings can be realised. The number of stacker cranes can be matched to the warehouse throughput instead of the number of aisles, therefore reducing the capital investment.

Unlike earlier models of aisle-changing cranes which had limitations in their aisle-changing flexibility, some of the latest stacker cranes have been designed with efficient aisle-changing capabilities. For example, warehousing stacker crane manufacturer LTW Intralogistics has produced a crane that travels to the end of an aisle, then travels perpendicular to the aisle and enters another aisle to continue storing and retrieving pallets. 

The company has designed a specialised track to facilitate the move, which requires no transfer mechanisms, supervision equipment or costly and time-consuming maintenance, problems that have plagued earlier aisle-changing cranes. 

The track enables the crane to smoothly rotate around the end of the aisle on a curved track, without leaving the track. It makes for an easy and fast transition between aisles. The ability to switch aisles increases redundancy, in the event that a crane would go out of service. Each pallet position then becomes 100 percent accessible. This also allows cranes to be easily moved off line when service is required into an off-line maintenance area. 

If an ASRS solution in place in a distribution facility has ten aisles and is employing ten stacker cranes each operating in its respective aisle, if a stacker crane breaks down there is no way to get products out of that aisle. With aisle-changing cranes operating in a situation like this, the DC operator could easily move the disabled crane to the maintenance area and the remaining cranes could complete the tasks required in that aisle. The redundancy system would assure that the pallets are retrieved. This is very important to maintaining a high level of delivery assurance. 

Patrick Roberts writes for Logistics Automation.

Konecranes supplies container handling equipment to Estonia

In April 2012, Konecranes received an order for two Rubber-Tired Gantry (RTG) cranes and two BOXRUNNER straddle carriers from the Estonian company A.S. Muuga Container Terminal (Muuga CT).

Konecranes has previously delivered three STS cranes and one RMG crane to the company, and expects to deliver the new straddle carriers in 2012, with the RTGs following in 2013.

Muuga CT is a multifunctional container terminal, handling both containers and Ro-Ro cargo in the port of Muuga. It is 100% owned by Transiidikeskuse AS. The container terminal has an annual capacity of 450,000 TEUs and plans to expand it.

Transiidikeskuse AS Chairman of the Board, Erik Laidvee, explained that the company chose Konecranes as its equipment supplier "due to our good experience with the previous deliveries of quay cranes and the RMG crane that we already have in our terminal."

"The local service has been excellent, and we are very happy with the fast response time whenever we have needed assistance from Konecranes," he added.

The RTG cranes Konecranes will deliver are equipped with a range of features, including an Autosteering feature which keeps the crane on a pre-programmed straight driving path, helping to improve safety and increase productivity.

Container handling efficiency is further increased by the Autostop feature, which assists the driver by automatically stopping the crane in the correct position for the target container or slot.

The CMS Remote Station crane monitoring system provides reports on crane failures and also provides the container terminal control room with the same information. An eco-efficient, fuel-saving system will also be included, which is designed to significantly reduce fuel consumption by eliminating high-speed idling, as well as reducing noise and emissions.

The BOXRUNNER straddle carriers are of 1-over-1 diesel electric design, and have a speed of 30 km/h, with four wheels out of six driven.

Both the RTGs and the BOXRUNNERs are equipped with the latest operator cabin design from Konecranes. In this design, special attention has been paid to ergonomics and visibility. The improved cabin has 60% more glass than conventional cabin designs.

Bauer supply gear motors for crane used to construct the longest cable-stayed bridge in the world

A crane manufactured by Mostovik Crane has been specially designed to complete a huge regeneration project of Russky Island, Russia, aimed at developing the area into a large-scale, contemporary tourist resort.

The development included the construction of a cable stayed bridge that would connect the island to the mainland Muravyov-Amursky Peninsula.

The unique crane was required to operate under extreme weather conditions including high speed winds and temperatures of -30°C during the winter months. Bauer was chosen by Mostovik to deliver suitable geared motors to complete the construction of the crane.

The Bauer BF Series geared motors, with torques form 10100 – 13400NM have set new standards for dependability and efficiency and were chosen for the total flexibility they provide as they can be mounted in any required position.

Bauer’s geared motors were particularly well suited to the Russky Island bridge application guaranteeing absolute reliability as they are concealed to IP65 as standard (IP66 optional) against dust and water spray.  The geared motors also provide comprehensive corrosion protection.

The erection of the bridge’s central span, made up of a hundred and three panels and weighing a total of twenty three thousand tonnes, was one of the most challenging phases of its construction, with the last section being lifted into place on April 2.

The completed structure is the world’s longest cable stayed bridge; reaching 70m above water level, stretching 1104m at is central width and pylons 320m in height supporting stay cables 580m in length.

In September, 2012, the regenerated Russky Island site will host the 24th meeting of the Asia-Pacific Economic Cooperation (APEC) leaders.

Konecranes receives significant industrial crane order from Indian steel manufacturer

Konecranes has announced that during the first quarter of 2012, it received one of the biggest single orders in terms of number of cranes and value to be supplied by the company to the Indian crane industry.

Totalling approximately EUR 9 million, the order is for 21 heavy duty industrial cranes that will be delivered to steel manufacturer JSW Steel's Torranagallu plant by the end of 2012.

JSW Steel is a large private sector steel manufacturer, and the flagship company of the Indian JSW Group. The JSW Group is present in several sectors including steel, energy, minerals, port and infrastructure, cement and aluminium.

The cranes to be supplied by Konecranes are fully automated, with lifting capacities that range from 15 to 60 tons. They will be integrated into JSW Steel's state of the art automated coil yard management system in the company's plant at Torranagallu, Karnataka.

Konecranes' Indian company WMI Konecranes India Ltd has been JSW Steel's preferred crane supplier right from the inception of this plant.

To date, WMI Konecranes has supplied more than 4,000 cranes to clients in India.

Photo: a Creative Commons Attribution (2.0) image from SignalPAD's Flickr photo stream.

Court “soft” on safety breach penatly for crane company

The Western Australian Supreme Court’s decision to halve crane company D&G Hoist’s $180,000 fine for breaching workplace safety laws, which resulted in the death of a 22-year old worker in 2007, was “too light” a punishment, according to the deceased’s parents, ” The West Australian reports.

Luke Murrie, had only been working at the Malaga yard for only a few weeks when a 375kg stack of gear fell on him, resulting in his death.

The company was initially fined $180,000, which included a $90,000 fine for the company, and $45,000 each for of the two directors, David Keating and Luigi "Gino" Decesare.

The penalty was reduced to a total $90,000, $70,000 for the company and $10,000 for the directors on appeal earlier this year.

Western Australia’s safety watchdog, WorkSafe, is appealing against the Supreme Court’s decision.

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