Linear motion solutions for OEMs

Traditional linear motion solutions require external guidance. However, a new linear motion approach eliminates external guides, is self-lubricating, and fits small applications commonly found in laboratory settings. The Glide Screw offers laboratory automation and medical instrument original equipment manufacturers (OEMs) something smaller, simpler, and more reliable than traditional options in many applications. In addition, it offers engineers a more compact solution while reducing downtime and lowering cost of ownership.

Featuring a smaller footprint than traditional round, plain, or profile rail bearing and screw systems, the system supports smaller instrument designs, making space available for additional functionality. It uses the outside of the screw as a bearing surface, removing the need for external guides, significantly reducing the size of the solution, and eliminating alignment issues during installation. Typical installation, surface preparation, and alignment takes one quarter of the time needed to install a profile rail-guided system.
 

Device design

As simple as a screw and a nut, the component can handle axial, radial, and moment loads. It has a bearing-grade finish with radial bearings that slide along the outside of the screw. The bearing interface is between the inside races of the radial bearings and outside diameter of the screw. Opposing reactionary forces handle radial loads where the bearings contact the outside of the screw. Twisting or moment loads also transition through the bearings.

Offering nearly maintenance-free operation, it uses an integrated, self-lubricating, lube-for-life system. A polymer block, contained within the lead nut, acts as a sponge with lubricant infused within its pores. As the nut moves along the screw, a small amount of lubricant diffuses from it. This keeps the Glide Screw lubricated and removes the need for any oil or grease within the laboratory environment, eliminating contamination risk.
 

Reliable precision

In a busy laboratory, instrument failure and downtime can be costly. A simplified design offers a much lower component count than traditional solutions, reducing the risk of failure and making the system easier to design into a machine. With no need to align for correct operation, there is no risk of misalignment, which can cause premature failure.

Offering a high level of precision for a range of medical applications, it handles small samples in diagnostic instruments and is efficient in dispensing pumps that have very little side load. In these applications, a profile rail is over-engineered. Even with little side load, traditional screws need some guidance to avoid problems with binding or chatter. The Glide Screw handles the pumping push/pull axial force and uses the outside diameter of the screw for guidance, eliminating the need for a micro-guide.

For pumping applications, it offers higher reliability and simpler maintenance and is a good option where many pumps need to be clustered together and a small footprint maintained. It gives OEMs greater freedom of design to ensure competitive advantage without traditional non-value-added cost.

Where extremely high precision is required, a ball screw may still be needed but, for many medical applications, the Glide Screw can easily meet requirements. It’s less expensive than the using precision-ground miniature ball screws and provides linear motion that is elegant, simple, and reliable.
 

Medical instrument market

The component’s design strips away things that add cost, complexity, and potential areas of failure, offering OEMs the possibility to reduce production cost, increase reliability, increase functionality, and reduce cost of ownership.

The device removes the need to over-design the instrument as it provides just the right solution with a long service and component life. The base product can also be customized to match engineering instrument requirements.

As an alternative to expensive, precision ground ball screws, the Glide Screw provides pre-alignment for easy assembly and a compact solution, which can improve the design of the final product. It allows engineers to identify inefficiencies previously accepted because of technology constraints and the potential for adding competitive advantage.

Engineers are able to re-think design possibilities with small devices when considering the Glide Screw, a highly reliable component for operation in small applications.

Thomson Industries Inc.
www.thomsonlinear.com

About the author: Jonathan Wray is the global product line manager – screws for Thomson Industries Inc. and can be reached at info@thomsonlinear.com.

Single pogo pin board-to-board contacts

The 70-9150 series single pogo pin board-to-board contacts provide low-cost, off-the-shelf connector solutions for a range of applications. Enabling design flexibility in pin count and placement location, the series features gold plating for high reliability and signal integrity and high-force stainless steel springs that facilitates consistent mechanical and electrical performance for up to 10,000 cycles.

Designed to mate with gold-plated PCB pads or flat contacts in docking or cradle applications, 70-9150 series contacts are suited to charging, data transfer, or programming interfaces for portable devices. Single pogo pin contacts are suitable as an interface between medical or measurement devices and their pluggable, disposable components.

Available in five contact heights – 1.9mm to 2.3mm, 2.4mm to 2.8mm, 2.9mm to 3.4mm, 3.9mm to 4.5mm, and 4.9mm to 5.5mm – AVX’s 70-9150 series is rated for operating temperatures spanning -40°C to 125°C and 1A current. Voltage rating for the series is based on placement distance. RoHS-compliant, the 70-9150 series is comprised of brass contacts with gold-over-nickel plating and SUS 304 grade stainless steel springs with a nominal 60g per contact spring force to maintain electrical connection in harsh environment applications.

AVX Corp.
www.avx.com