​ What are some linear motion options for moving multiple loads independently?

From a mechanical perspective, one of the more challenging applications in linear motion traditionally involves moving two or more loads independently, as required by some handling, transportation, and inspection applications. While using multiple linear systems or pre-assembled actuators is a simple mechanical solution, this option typically requires a significant amount of space and cost. But there are several types of linear systems that allow users to install multiple loads and move each load independently.

One of the most common linear motion systems used to move multiple loads independently is the linear motor. Most linear motor designs (with or without iron cores) use thrusters that contain windings and are directly fed, so multiple thrusters can be mounted on the rail and controlled using different travel curves and strokes. Linear motors with multiple thrusters or sliders are usually used for high dynamic movements that require very precise control of speed or position. In fact, many conveyor systems based on linear motors are based on the concept of linear motors with multiple thrusters.

Because each thruster (slider) is directly powered, linear motors are ideal for applications where multiple loads need to be moved independently.

Another traditional linear motion system that allows multiple loads to move independently is the rack and pinion drive. Because the motor and gearbox are mounted directly onto the pinion, it is relatively simple to mount additional motor-pinion combinations on a single rack, each programmed for a specific stroke and movement curve. Rack and pinion systems with multiple independent sliders are ideal for large gantry frames and transportation applications, often used in robotic transmission units.

The pinion is driven directly by a motor-transmission combination, making it easy to assemble multiple pinion gears onto a single rack, with each pinion driven independently.

In a two-belt design, one belt is fixed and the other drives around a driven pinion with idler rollers on each side.独立移动多

But not the typical pulley arrangement many of us are familiar with. This type of linear actuator uses two belts configured in a specific way, similar to a rack and pinion drive.

A belt is static and mechanically secured to the base, for example by squeezing - similar to the rack in rack and pinion drives. The other belt is a short, continuous loop that snakes through the motor driven pinion and through the idler wheels on either side of the pinion. The load is connected to a slider that contains the moving motor-pinion combination. As with rack and pinion systems, the dual belt actuator design makes it simple to add more sliders (each with its own motor pinion assembly) and control them independently. The dual belt design also places tension where the belt meets the pinion, thereby eliminating clearance and minimizing belt stretch.

There are also actuator designs that use two ball or lead screws - one with left-hand thread and one with right-handed tread - pinned or welded together. Each screw has a nut and slider, and a motor drives the entire assembly. This setting allows the sliders to move at the same time, but in opposite directions - using the same moving profile towards or away from each other. This arrangement is less flexible than the linear motor, rack and pinion, or double belt designs described above, but is useful in applications that require pinch-type motion with precise force and speed control.

Some screw driven actuators contain left - and right-handed screws, are welded or mechanically connected and are driven by a single motor. Each screw has a nut, so loads move toward or away from each other in the same moving profile.

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