ULTRALIGHT Torque Limiters – Quick Reacting and Readily Available Model SLE : Pressreleases

R+W America Press

Proper torque overload protection is often omitted from machine design due to concerns over size, inertia, and performance – not to mention long lead times. The R+W ULTRALIGHT SLE series helps to address all of these concerns with a compact low inertia design that runs with zero backlash and disengages in the shortest possible time at overload. It’s also available for delivery in just a few days.

Precision ball-detent torque limiters have long been considered the standard for fast reacting, accurate and repeatable overload disengagement devices. Being part of the mechanical system, they are literally best positioned to respond to torque overload and protect equipment from damage in case of a machine jam, crash, or other malfunction. This is because they react to real time forces rather than estimating the torque generated by the motor electronically, which also tends to neglect system inertia. In many situations, the built-up inertia is significant enough to damage critical components in the driveline if the forces are not mitigated during an overload event.

Even with this being the case, older torque limiter designs pose problems for more up to date machines and business models alike. Most new industrial equipment is designed to run with unprecedented speed, accuracy, and energy efficiency. Older torque limiter designs are relatively large and heavy compared with standard servo couplings, which can make them unsuitable for fast accelerations. Compounding the issue is that most precision ball-detent torque limiters are made to order and can take many weeks to deliver, whereas the drives, motors, gearboxes, couplings etc. that they would be used with are often available for delivery in a matter of days. As a result, many engineers are left to assume the elevated risk of torque overload damage and costly machine downtime.

These obstacles can be overcome with the ULTRALIGHT SLE series. By incorporating lighter materials into its proven ball-detent design and integrating it directly into its SERVOMAX EKL compact elastomer couplings, R+W has been able to dramatically reduce the size, weight, and inertia of inline ball-detent safety couplings with the model SLE. Compared with using standard precision shaft couplings, the increased size and inertia associated with adding mechanical overload protection is rendered nearly negligible. The further advantage is that the modular design allows for subassemblies to be stocked in advance of customer orders, and then to be bored (keyway optional) and set to the correct disengagement torque. Bypassing the traditional method of starting to build the clutch after the bore diameter has been selected reduces the lead time to a fraction of what it used to be.

All of this adds up to the old trade-offs associated with use of mechanical overload disengagement devices being significantly reduced – meaning torque limiters belong in high tech machines.