Portable surgical microscope moved cleanly

The microscope is primarily used by ophthalmologists worldwide for cataract surgery. It enables the disease, by far the most common cause of blindness worldwide, to be surgically removed relatively easily and helps people to regain their sight.

The microscope stand is a multi-jointed, manually moved arm system in which all the main joints are equipped with rotary bearings. Both radial and radial-axial bearings are required here.

In addition, the parallelogram arms require bearings at their joints and an internal guide for the clamping baffle plate.

Due to the required smooth running properties, only rolling bearings were used originally. However, as these take up a lot of installation space and are relatively heavy, the developers looked for a more compact, lighter alternative. Metallic plain bearings were ruled out due to their repeated need for lubrication and the resulting risk of contamination.

Installation space, cost and maintenance considerations clearly favoured our plastic bearings made from iglidur G, the all-round material with very good friction coefficients.

Cylindrical iglidur G plain bearings are used in the main joints, where they not only fulfil bearing functions but also enable the joint to be clamped due to the local radial pressure on the bearing. In addition, larger flanged bushings are also installed as radial/thrust bearings in the main joints.

Smaller flanged bushings allow direct integration into the sheet metal components of the parallelogram arm without additional bearing mounting parts. They also offer the option of using commercially available hinge pins instead of expensive production parts.

An iglidur G thrust washer is used to lock the parallelogram arm.

The advantages of plastic bearings in terms of space requirements, price, installation effort, freedom from maintenance and hygiene more than compensate for the minimal loss of smoothness.