When selecting actuators for applications such as folding sprayer booms, agricultural OEMs used to have the choice of either hydraulic or pneumatic. Now, however, the latest generation of linear actuators, such as the H-Track from Thomson Industries, are said to offer the required performance without the traditional drawbacks of these other technologies. With the H-Track electro-hydraulic

NSK explains why its ball screw actuators and linear guides are meeting the demands of medical imaging and MRI equipment

NSK offers linear motion systems that are said to be suited to the accuracy and precision of medical imaging equipment such as MRI (magnetic resonance imaging) scanners


ithin the healthcare industry, medical imaging and MRI

equipment needs to be reliable and high performance, as uneven surfaces or inconsistent movements can produce unreliable results or information that can lead to sub-standard care for patients. Designers of such systems therefore need to consider every component – including the ball screw actuators and linear guides. To meet the requirements, NSK offers

“As the linear guides use precision technology, advanced surface treatments and

high-quality lubricants,

they are better equipped to move components along linear planes

without unnecessary friction”

linear motion systems that are said to be suited to the accuracy and precision demands of medical imaging equipment. In MRI scanners, for example, one of the most important components required for successful operation is the motorised ball screw which utilises cylindrical motion to move the machine’s imaging equipment along a plane with extreme accuracy and precision. Since this equipment is large and complex, these ball screws must accommodate heavy loads and produce movement that is sufficiently smooth and consistent to generate clear and reliable results. MRI technology also requires the use

of high magnetic force, so the ball screws and other components need to function in this type of environment without affecting the machine’s energy. According to NSK, its ball screws are ideal for use in MRI scanners as they provide both the load-bearing capabilities and smooth movement required. Smooth motion not only contributes to accurate results – thus avoiding potentially disastrous misdiagnosis – but improves patient comfort and safety during scans, the company explains.

16 NOVEMBER 2020 | DESIGN SOLUTIONS Some types of ball screw feature

circular arc grooves, but with these the balls can get wedged. NSK, however, uses offset gothic-style arch grooves to avoid this by minimising the available clearance between the balls and grooves. In addition, durability is boosted through the use of purified alloy steel, while any potential for backlash is eliminated thanks to an application of preload. NSK’s linear guides are also found

widely in medical imaging devices. Designed to move various components along a single plane, these deliver smooth motion, functionality and reliable movement over a significant period of time. As the linear guides use precision technology, advanced surface treatments and high-quality lubricants, they are better equipped to move components along linear planes without unnecessary friction. Over the long term, this capability reduces the opportunity for wear, boosting the uptime and operational life of medical imaging systems. The company’s NH linear guides are

said to offer double the lifespan of conventional products due to the inclusion of features such as specially developed ball groove geometry. These also provide high dynamic load rating, long maintenance intervals, low noise output and simple installation. To further meet application demands,

the company’s linear guides and ball screws can be customised to suit specific requirements.

NSK Europe


actuator, the motor, pump and valves are integrated into a mini ‘Power Pack’ mounted onto the cylinder. This allows completely self-contained hydraulic actuation without the need for external pipework. This is also able to exert forces up to 22kN and is designed to withstand the punishment that would destroy many other electric actuators, the company claims. Lubricated for life, H-Track is

connected via two wires, with all external pipework eliminated, expediting installation and maintenance. Eliminating pipework also negates the risk of crop contamination due to fluid leakage. Space efficiency is also enhanced, as

the self-contained H-Track combines all of its required features within the power pack and cylinder. Packaging is consequently improved as well as overall weight, helping to improve efficiency. Another advantage is the reduced

power requirements of the H-Track. Without the requirement to power external systems, the H-Track is less power intensive, improving energy efficiency. Additional capabilities include an immunity to vibrational drifting and hydraulic self-locking when load is reversed. The compact pump and valves can also be configured to the requirements of each application. H-Track can be specified in either

IP67 or IP69K ingress protection ratings, with a standard operating temperature range of between -40˚C and 82˚C.

Thomson Industries

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