Move and fix samples safely

In order to be able to process samples in biomedical research with high throughput, laboratory personnel need ergonomic workstations. When redesigning a sample head holder, the engineers opted for high-quality mechanical machine elements that safely regulate speeds and reliably fix masses weighing up to 10 kilograms.

Breaking unconventional ground in design solutions is part of tech-solute GmbH's daily business. The Bruchsal-based company, which specialises in technical product innovations, was founded in 2002 by Dr.-Ing. Marcus Saak and Dr.-Ing. Dirk Schweinberger, who were then mechanical engineers at the Institute for Product Development (IPEK) at the University of Karlsruhe. While their focus at the beginning was purely on concept development, the range of services offered by their company expanded with the increasing wishes of customers to implement technical ideas through to near-series designs.

Accordingly, tech-solute today develops a variety of ideas under the management of the two owners until they are ready for series production, creates functional models as well as prototypes and accompanies the process of its own and the customer's innovation development. For example, tech-solute recently developed and prototyped an assembly aid for working on laboratory samples for a customer in the field of biomedical measurement technology. This new design makes it possible to move the sample head freely in different planes and to position it without force. The mounting aid is then securely fixed in the best possible position for the staff and the samples. For this purpose, the application combines four clamping elements and a gas pressure spring from ACE Stoßdämpfer GmbH in one design.

Fast, cost-effective and efficient solution sought

By cleverly combining these and other components and thanks to agile product development, the mechanical development team around project manager Philipp Aders from tech-solute succeeded in building a functional sample head holder as a prototype in a short time, which has already proven itself in production tests. Dirk Schweinberger comments on the procedure: "Since we were looking for a fast, cost-effective and efficient solution, the plan was to use standard components. We knew the advantages of ACE's machine elements from past projects. For example, the clamping elements allow fixing in any position, and thanks to the gas pressure spring, the up and down movements are jerk-free and power-saving." In accordance with the order and the requirements of modern laboratory work, the handling comfort for the operating personnel of the sample head is in the foreground. The new design of tech-solute makes it possible to adjust all four axes individually. Only one hand is needed to release the respective axis and the other to reposition the specimen. Compared to the ball vices previously used by the customer for this purpose, the operation has been made easier in the truest sense of the word.

"Up to now, it happened in the laboratory that the direction of movement was not always really predictable with a sample weight of up to ten kilograms. This meant that the staff had to additionally secure, hold and align the samples manually," Philipp Aders describes the previously cumbersome, time-consuming and error-prone work process. The new mounting aid, on the other hand, allows for contemporary mounting, says the designer, who adds: "Thanks to the four axes, the specimen can now be positioned in such a way that all areas where assembly and soldering are required can be reached comfortably without the fitters having to contort."

High-quality series components found

The assembly aid is attached to a height-adjustable table on which there is a vertical linear guide made of aluminium. This makes it possible to move the entire rod end up and down relative to the table top, electrically driven. To facilitate lifting and lowering of the specimen head holder, a gas pressure spring of the type GS-22-250 from ACE is installed. When selecting these, the desired rapid implementation was supported by the calculation and configuration tools on the ACE Stoßdämpfer GmbH homepage.

Customer-specific designs and orders are thus possible within a short time. In the case of ACE industrial gas springs, the subsequent customised filling and delivery usually takes place within one working day. Gas pressure or gas traction springs are best used when reliable support of muscle power by means of a hydraulically functioning machine element is desired. Once the sample head holder is in the desired position thanks to the mechanical assistance, a clamping unit for linear guides from ACE takes over the locking function.

The machine element of the type Locked PLK30-1-4B is characterised by its compact design and stands for highest holding forces even with greased rails. "It is released via a button on the joint head, which releases the clamping unit by applying pressure," says Philipp Aders, pleased with the precise hold and the ease of work. Further clamping forces act on the housing, which is mounted on the linear slide. This is where the first rotation axis of the assembly aid, arranged perpendicular to the linear guide, can be found. Two type R70-4B rotary clamping units from ACE are responsible for rotation and locking. In addition, a rod clamping element of type PN63-20-2-4B is installed centrally between the rotation clamps.

In addition, slide bearings ensure that only rotation and no translation is possible when the rod clamping is released and that the axle is supported in the intended position. These three axes are used for flexible orientation of the sample head. All components for fixing are released via pneumatic valves and are tightened in the normal state. For the rotation of the sample head around its own axis, the tech-solute team has provided a bearing via three rollers, which is held by a brake block. The inner ring of this bearing can be split and makes it possible to attach a variety of different specimen heads to the mounting aid. Business manager Dr.-Ing. Dirk Schweinberger sums up: "As requested by our customer, an overall design has been created that allows an optimal interplay between controlled movement and secure fixation in any position desired by the laboratory staff."