Lubrication-free lead screw technology in maintenance-free stands for surgical microscopes

• What was needed: space-saving alternative for a linear guide in the AB slide
• Requirements: design as compact as possible, good running properties, low friction, lubrication-free, maintenance-free
• Industry: Medical technology
• Success for the customer: The new trapezoidal spindle and lead screw groove are so compact that several cables could be fed through the centre of the AB slide. This was previously not possible. A clearance-free and low-friction movement also ensures lubrication-free and maintenance-free use over the entire service life.

Some of the stands for surgical microscopes from LEICA Microsystems AG are equipped with a so-called "AB slide". This is located between the support arm and the microscope. It consists of two slides, which are arranged at right angles to each other and have the task of moving the centre of gravity of the microscope including the accessories into the rotary axis so that the microscope can be rotated in a balanced manner. Movement is either manual or motorised.
For a new stand for dental applications, there were special design requirements and the desire for a construction that was as compact as possible. A new AB slide had to be developed to meet these requirements. Existing systems were previously always equipped with two linear guides and a spindle in the A and B slides and were therefore too large.

When developing a new solution that can be used for dental applications, one of the two linear guides was replaced by a dryspin® trapezoidal spindle (TR 10x2) made of stainless steel with a lead screw nut . The system is so compact that several cables could be fed through the centre of the AB slide. This would not have been possible with the previous concept due to a lack of space. The new concept with just one linear guide and one spindle has solved this problem. In addition, the good running properties of the material allow the spindle to be used both as a guide and as a drive unit. A clearance-free and low-friction movement ensures maintenance-free and lubrication-free application over the entire service life, whereby lubricants are not permitted in this area anyway.