As a patient in hospital, it can seem as though one day lasts more than 24 hours. Television and reading is often the favourite pastime for many. To enable the patient to conveniently position the TV for his or her sitting or lying position, more and more hospitals are equipping their stations with height-adjustable pivoting arms, which are simply mounted to the bedside table. However, hardly anyone knows that these pivoting arms come from a family business in Münsterland. For a hygienic and smooth adjustment of the arms, the mechanical engineering company has been relying on the lubrication-free and maintenance-free plain bearings from igus for years.
However, the first height-adjustable pivot arm developed in early 2000 was not for everyday office needs, but for medical technology. "Siemens enquired for a custom solution for mounting a TV/telephone system to patient beds in hospitals", says Herbert Schwering. The screen arm had to be very smooth and individually adjustable so that the patient can align the screen according to their individual needs with little effort. Said and done! And in this way the passionate designer developed a height-adjustable pivot arm.
For the screen adjustment, a plain bearing was sought that would allow easy adjustment. . Due to hygiene regulations in hospitals, the bearing point should not be lubricated. Plain bearings with a long service life are of great advantage here, as there is no need for replacement.
With our bearings made of iglidur G material and thrust washers made of iglidur W300 a perfect combination was put together in this application. The dry lubricants incorporated in the material mean that no additional lubrication or sealing of the bearing point is necessary . The good coefficient of friction ensures a long service life and easy adjustment of the monitor .
The pivot arm has a swivel range of –18 to +38 degrees from the horizontal. The monitor support can be tilted from –30 to +20 degrees. In order to implement these movements smoothly, the company mainly relied on lightweight components such as steel, aluminium or plastic in its construction. For mounting the arm, Herbert Schwerings went straight to the motion plastics specialist igus. "We have been using igus components for decades and are always very satisfied with the quality of the products and the advice", says the designer. "That is why we also thought of the igus bushings when mounting the adjustable arm." “
Eight plain bearings made of wear-resistant high-performance plastic iglidur G are used in each arm. Like all iglidur polymers, the all-rounder material is lubrication-free and therefore maintenance-free. Very important because the medical environment poses the highest hygiene demands on the technology used. Another criterion is the noise intensity. The plain bearings are very quiet during motion and ensure adequate support. The price was also relevant: "The plain bearings not only have to be abrasion-resistant and durable, but also have a good price/performance ratio. The company igus was able to do this to our satisfaction with iglidur G," says Martina Schwering. The qualified industrial engineer has been in the management of the family business since 2014.
"It is important to us to be able to handle a large number of enquiries quickly and at short notice, which is why we manufacture our pivot arms in our own production facility", says Herbert Schwering. The company receives the raw material for the inner workings of the arms as a specially produced aluminium extruded profile. The profile is cut to the appropriate length on site and processed on the most modern CNC machines. The eight plain bearings are then pressed into the ends of the profiles.
Then an employee assembles them with various other components: the powder-coated cover plates, the device carrier and the fastening piece for mounting on the bedside table. Another advantage of the pivot arm is that the cables from the television and telephone can be integrated directly into the arm. The proverbial cable spaghetti is therefore avoided and ensures increased safety and hygiene in the hospital.
Depending on the type of monitor, a special tension spring is used to balance the weight so that the pivot arm can carry different loads. There is also a brake integrated in each arm, which can compensate for different loads during use. "If the patient removes the handset from the pivot arm, for example, the arm should not lift; here the brake helps to stabilise", explains Herbert Schwering. Maschinenbau Schwering sells up to 6,000 height-adjustable pivot arms every year. A large part of which is marketed by Siemens to hospitals worldwide.
The family business relies on igus high-performance polymers not only in the height-adjustable pivot arm, but also in other screen adjustments. For example, iglidur plain bearings and thrust washers are used for the new monitor adjustments of a large American phone company.
In the new screen adjustment system, the monitor can be turned using an iglidur W300 thrust washer. The lubrication-free long-term endurance runner impresses here mainly by its low coefficient of friction, very long service life and extremely high wear resistance. An iglidur G plain bearing ensures an easy and quiet tilting of the device carrier. "We will continue to rely on igus plain bearing technology for further projects in the future", says Herbert Schwering.
To the products used