90% of small U.S. construction companies have safety programs, but only a third have programs to improve the ergonomics of workers’ environments. It’s too bad, because the risk of musculoskeletal disorders (MSDs) is especially high in construction workers. Plus annual wage and salary losses are estimated at $46 million for the U.S. private-construction sector. Workers […]
Ball + leadscrew driven
Electric actuators displace other motion options — including manual designs: A Motion Trends report
Today, electric actuators are easier than ever to specify and install. Value-add services from component suppliers as well as application-specific actuator product lines (especially for battery-powered designs in mobile equipment and consumer use) eliminate many integration tasks for OEMs and end users. These are trends supported in part by a movement Design World has tracked […]
Beam deflection equations for linear systems
When a linear guide, such as a round shaft or profiled rail, deflects or sags, the bearings that travel along the guide experience edge loading (a higher load concentrated at the ends of the bearing), which can cause rough, irregular movement, increased wear, and reduced bearing life. And when a linear guide is incorporated into […]
When should you lubricate a lead screw?
It’s expected that a ball screw, with metal-on-metal rolling contact between the balls and the raceways, will require periodic lubrication with either grease or oil. One of the advantages that lead screws have over ball screws is that they can often operate without lubrication — eliminating maintenance and the potential hazards that come with using […]
When is resolution important for linear systems?
Accuracy and repeatability are standard specifications that describe how a linear motion system behaves along its travel and how closely it reaches the intended position. Resolution, on the other hand, is less often included in performance data for linear motion systems, but it can be equally important as accuracy and repeatability in some applications. In […]
Ball screw preload: What you need to know
When a linear motion application requires high thrust force and rigidity along with good positioning accuracy, a preloaded ball screw assembly is often the best choice. Manufacturers offer ball screw preload amounts ranging from just 1 or 2 percent for applications where backlash would be detrimental, up to 10 percent or greater for applications that […]
Gallery: Rod style actuator variations and uses
Linear actuators can generally be classified as either slider style or rod style. With a slider style actuator, the motion is constrained to the limits of the housing length and the load is mounted to a slider or table. With a rod style actuator, motion is produced by a rod that extends and retracts from […]
Can a linear actuator provide the rigidity and accuracy of a linear stage?
Although there are no industry standards that define linear actuators and linear stages, generally accepted terminology indicates that a linear actuator is typically constructed with an aluminum extrusion or base, while a linear stage is typically built on a flat, machined steel or granite base. This distinction implies that linear actuators can provide longer strokes […]
Tolomatic electric actuators with longer strokes (to replace fluid-power cylinders)
Tolomatic high force electric rod-style actuators now feature stroke lengths to 1.5 m (60 in.) for more flexibility for converting motion control applications with hydraulic or pneumatic cylinders to electric linear motion. Designed for high duty-cycle performance in demanding applications, the RSX, RSA and ERD electric rod-style product families use planetary roller screws for longer […]
Lead screw selection: What should I consider besides diameter and lead?
Once you’ve gone through the process of sizing a lead screw, you know what diameter and lead will provide the required load capacity, speed, and back driving torque for the application. But there are hundreds — maybe thousands — of lead screw designs on the market. Beyond the basics of diameter and lead, how do you […]
