| Sitting pretty |
New Demag DC electric chain hoists in the field
The new DC electric chain hoists made by Demag Cranes & Components have passed one of their first field tests at the Wörth plant of the renowned seat manufacturer Grammer. The hoists, which are each fitted with a Manulift control handle, provide above all a high level of ergonomic handling and performance as well as reliability and a long service life.
Established in 1999, Grammer Wörth GmbH is part of the Grammer Group, which achieved sales of almost Euro 800 million with 7000 employees in 26 subsidiaries last year.
The company is located on the premises of DaimlerChrysler in Wörth-Rhein, in the Rhineland Palatinate region, and mainly supplies the automotive manufacturer's truck production facility there with seats. Grammer Wörth supplied 42,000 seats to DaimlerChrysler in 2003 alone, deliveries this year are expected to rise to some 45,000 units. The range of seat variants is manufactured from 72 basic versions, which Grammer Wörth GmbH receives from a Turkish sister company.
Improved ergonomics and performance
For handling the seats, Grammer uses three of the new DC electric chain hoists fitted with Manulift control handles supplied by Demag Cranes & Components from Wetter/Ruhr. By means of a quick-change coupling, the Manulift unit can be used to connect customer-specific tools for handling the seats, among other items. This enables the operator to move the load horizontally with one hand; at the same time he can control the infinitely variable lifting and lowering speed with his thumb. The combination of DC electric chain hoist and Manulift unit results in an ergonomic workplace device, which protects workers from excessive physical burden.
The assembly workers at Grammer also benefit from the ergonomic design, particularly when they have to position the seats with one hand with such precision that they can be bolted into place, while the load is guided with the other hand.
The new hoists enable the company to achieve a tangible increase in throughput in this sector, which works in two shifts, and to meet one of the main demands of the just-in-time operation at the DaimlerChrysler plant. In addition to the high performance, Grammer demanded a sufficient load capacity for the chain hoists and smooth handling, to ensure that the seats reach the customer in perfect condition.
Operating sequence
The three DC electric chain hoists are in operation at various points along the assembly line. Grammer uses one of them at the infeed station to the roller conveyor installation which transports the seats through the assembly line. The employees who work here remove the relevant seat from its original packing using the chain hoist and place it precisely on the load carrier. When the seat has been bolted together, it is transported by the roller conveyor for further assembly and a check and then to final inspection. An automatic line finally leads direct to the truck.
The other two chain hoists with Manulift are installed at an outfeed station for any reworking and at a repair station.
Wide range of integrated standards
Besides the ergonomic benefits and its state-of-the-art technology, the new DC electric chain hoist also offers a wider range of integrated standards. This means that customers already benefit from product features in the standard design, which are otherwise only available as costly options, or not at all.
These include the monitored brake and slipping clutch principle based on speed. This technical innovation ensures maximum safety and reliability and minimised maintenance thanks to low wear; this benefit also contributes significantly towards a longer service life. In addition, the brake and slipping clutch principle prevents the load from creeping or slipping as the result of an operating error. Other examples for the extended standard are operating limit switches for the highest and lowest hook positions and an elapsed operating time counter. Furthermore, Demag generally supplies the chain hoist with two hoist speeds.
Higher availability
Due to the 2m+ classification according to FEM, the DCM electric chain hoists used by Grammer are rated for service lives of at least 1,900 hours at full load. This additional availability provides considerable advantages for two-shift operation, since repairs and general overhauls only have to be carried out at a much later date. In order to secure the availability of the hoists and, therefore, continued production further, the units can be swapped with each other in the event of a malfunction. The installations are fitted with plug-and-socket connections as standard – for the power supply and control cable, for example – and can easily be changed by the operator himself. Grammer has also concluded a maintenance and service agreement with Demag. The agreement includes annual maintenance intervals and regular checks of the installations according to statutory accident prevention regulations.
Good experience
When Grammer was looking for a supplier for hoists to replace the existing equipment, the decision was made relatively quickly in favour of Demag Cranes & Components. Reasons for this were the close proximity to the customer, good value for money and the maintenance work provided by Demag Cranes & Components. Furthermore, Grammer was also able to refer to the good experience of its Turkish sister company, which has been using Demag chain hoists on its seven assembly lines for years.
In order also to meet rising demand, Grammer designed the system in such a way that the infeed station can be extended. In this case, the workplace could be expanded and a second slewing jib crane with an electric chain hoist installed.
