• What was needed: iglidur slewing ring bearing PRT-01-60-TO-HTD8M with outer drive ring
• Requirements: A light and compact solution was sought for the bearing and drive of the rotary disc, which at the same time has a high mechanical load capacity.
• Industry: Camera and film technology
• Success for the customer: The iglidur bearing is an cost-effective and lightweight alternative to roller bearings. It offers sufficiently high resilience in all directions and suppresses vibrations.

The two rotary discs at the top and bottom of the rotary table were mounted with iglidur PRT slewing crane bearings.

Problem

Rotary tables are used in product photography in order to be able to take products fully or semi-automatically from all sides.
However, the rotary table implemented in this application can also present products that do not have flat surfaces or are very narrow (e.g. inline skates or smart phones). It is fixed in place thanks to another rotating plate above the product. A pivot bearing is also used for this purpose, which moves synchronously with the rotary disc below. In order to be able to fix products of different heights between the two plates, the upper rotary disc can also be adjusted in height.
This adjustment is made by means of two electric lifting columns in the front area of the rotary table. The rear area, on the other hand, should be kept free in order to keep the time required for post-processing the images as low as possible. Since the two columns cannot carry much weight, the rotating unit attached to them should be made as light as possible.
In addition, the objects are often clamped off-centre, especially in the case of holders for a 2nd rotary axis, and this leads to an asymmetrical load on the bearing. This load situation is difficult to control with simple plain bearings. A solution that was as light and compact as possible and required only a few components was sought for the bearing and drive of the rotary disc. A high mechanical resilience combined with low speeds was also required.

Solution

The iglidur slewing ring bearing PRT-01-60-TO-HTD8M with an outer drive ring made of aluminium particularly meets the requirements of the application. Compared to conventional solutions with roller bearings, it is significantly lighter and affordable, but at the same time offers sufficiently high load capacities in all directions. The integrated external toothing also enables a direct drive via a stepper motor with a gearbox. Since an additional gear reduction (i=3) was achieved via the ratio of the outer circumference of the bearing to the outer circumference of the drive wheel, the motor could be dimensioned correspondingly smaller, which further reduced costs and weight. The vibration-dampening specifications of the slewing ring plain bearings also have a positive effect. In conjunction with the toothed belt, possible vibrations that could be induced by the stepper motor are effectively suppressed. The drive generates a smooth, even rotary movement without causing the sheet metal parts used for the housing to vibrate. The sliding elements of the PRT slewing ring bearing are made of the maintenance-free material iglidur J, which runs completely lubrication-free. The function of the rotary table bearing is thus ensured in the long term and even under high loads.

The second platform at the top makes it easy to fix uneven objects. The height of the platform is moved via the two columns.

In detail: The iglidur PRT slewing ring bearing. In use, it allows a vibration-free, light and cost-effective bearing of the rotary disc.