Lubrication-free plastic bearings for ergonomic office chair

Sprawling explicitly allowed: That is the feature of this high-quality office chair from Nowy Styl GmbH, developed by the famous French architect Françoise-Hélène Jourda. A healthy and stable spine is fostered by the constant change between hollow and rounded backs. Four patents ensure the extraordinary seating comfort. Lubrication-free and maintenance-free iglidur polymer plain bearings from igus also ensure the absolutely essential smooth operation in the various settings.

"Research results have shown that leaning against the backrest in slight kyphosis relieves the spinal column most effectively," reports Corinna Graf, Marketing Manager at Nowy Styl GmbH in Ebermannsdorf. "Independent studies have further shown that, as a rule, very few users utilise all available seating functions despite appropriate briefing on their office chairs. " These findings have been incorporated in the development of the Galileo executive chair, whose settings are largely automatic. The internationally renowned French architect and designer Françoise-Hélène Jourda gave it its distinctive look.

Problem

The office chair should not make any noise during adjustment and use. In addition, lubricants should be avoided to prevent contamination and maintenance costs. The metallic bearings and needle roller bearings previously used in this chair were also custom-made and very expensive to produce.

Solution

With the standard materials iglidur G and J a large variety of plain bearings is available. Special requests can be implemented easily and flexibly. At the same time, both materials offer a wear-resistant solution for the office chair that requires no additional lubricants. Maintenance of the bearing points is therefore not necessary.

"Today we can say that they are proving themselves. So far we have not had any complaints. “

Franz Eckert, design manager, about the decision to use iglidur plain bearings.

Four times patented chair

The office and contract chair manufacturer has decided to use iglidur plastic bearings from igus GmbH instead of metal or needle roller bearings. They are lubrication-free and therefore maintenance-free as well as extremely versatile and are available either from the catalogue range or as a tailor-made special solution with no minimum order quantity. They are basically optimised in terms of coefficients of friction and wear. In addition to the very good price/performance ratio, the high degree of quietness speaks for its use in this high-quality office chair. Plain bearings made of the materials iglidur J and iglidur G prove their versatility for the various pivoting movements and iglidur J liner from the drylin R range do the same for linear movements.

Four patents have been incorporated into the inner workings of Galileo, which, together with the further development of the proven and patented "Glide-Tec" mechanism, redefine ergonomic sitting. The central element is the "Glide-Tec+" mechanism - a movable seat surface which, in combination with a patented three-dimensional movable backrest, enables optimum mobility when sitting. Added to this are the support of the ergonomically desirable change between hollow and round back by the patent for supported lordosis-kyphosis movement as well as patents for a simplified seat depth adjustment and automatic weight adjustment.

Seat depth adjustment of the office chair with iglidur plain bearings

JUM liners for seat depth adjustment. Works noiselessly and smoothly.

Lubrication-free plain bearings for the kinematics

With the patented "Glide-Tec+" motion kinematics, the high-performance plastic plain bearings show their strength. The lordosis-kyphosis adaptation, a kind of artificial spine, is the special highlight of the chair. Movable plastic elements rest on two curved metal rods that rotate when the user leans back. This bends the support elements in such a way that the shape of the backrest precisely matches the respective seating position. It is one of the most flexible backrests in the world.

The rotary motion is implemented by flanged bearings made of the versatile material iglidur J. In this application, it features a hard-chromed shaft for maximum wear resistance and noise-free operation. Due to the necessary tolerance compensation and in order to reliably support ease of movement, compensate for any play and achieve the required low noise level, the plain bearings are pre-loaded. "For a chair in this price segment, squeaking, creaking or juddering should never actually occur," confirms the head of design, Franz Eckert.

The plain bearings in the office chair are designed for a weight of up to 200 kilograms. If the user sits down, the weight is measured automatically. When this high pressure load occurs, the material iglidur G demonstrates its strength. It is an economical universal bearing with flange, which is available from stock in over 650 dimensions. The main design advantage in this application is that it can permanently withstand the high static loads without being damaged.

iglidur G bearings permanently withstand the high pressure load during automatic adjustment and sitting.

In the area of seat depth adjustment, here a pure linear movement, JUM liner made of the material iglidur J displays its strength. Due to the special crossbar structure, they are predestined for linear movements, have low coefficients of friction and, with stainless steel as counter partner, have the very good running performance and noise behaviour required in the long term. "The dreaded stick-slip effect does not occur anywhere," the design manager points out an essential aspect. "All settings function reliably and noiselessly. “

Positive aspects can also be seen in the absence of lubrication. The high-quality office chair is available in innumerable variants and is assembled according to customer specifications at the company site. "Since the fitter no longer has to grease anything, the risk of unintentional soiling of the very high-quality seat or backrest upholstery is reduced," Eckert comments.

Standard parts in focus

In the executive chair, which has been on the market since 2006, only standard plain bearings from the extensive igus modular system, which has the right bearing for almost every application, are used. Special solutions for plain bearings should be avoided from the outset in order to concentrate on the main topic - the ergonomics of the chair. Extensive sampling and technical consultations took place prior to development.

The bearings have subsequently been subjected to a wide range of tests on in-house test rigs. The main focus here was on smooth running, low noise, robustness and durability. "But it is only during actual on-site use that it becomes apparent whether all requirements are met," says Eckert. "Today we can say that they are proving themselves. So far we have not had any complaints. " The decision for using the plastic bearings has also paid off in terms of economic efficiency. The savings achieved by using igus plain bearings are estimated at around 50 percent.

Cinema seat with popcorn chute

The polymer bearings are now successfully used in other chairs of the manufacturer. In the case of cinema seats, for example, which incidentally can also be equipped with a popcorn chute to make it fall to the floor in the desired direction, thus facilitating cleaning work, they ensure extreme robustness. Here, all rotating bearing points are equipped with polymer bearings.

With the high-quality office chair Galileo, a triad of design, ergonomics and seating comfort has been realised. The functions support the human being's natural urge to move even when seated and keep the back healthy. "Even sprawling does no harm," says the Marketing Manager in conclusion. The design manager adds: "The polymer bearings help to implement the respective motion sequences without any problems. “