From pick-and-place equipment to linear transfer lines, moving work pieces and finished products from point A to point B is a major part of today’s production environments. In many cases, speed, precision and safety are top priorities. Protecting both operators and equipment from impact forces is a critical task—one that is often accomplished with shock absorbers and safety dampers. In the case of linear modules that must endure high speeds and loads, safety dampers provide insurance against impact damage.
Michigan-based ACE Controls designs safety shock absorbers to protect people and equipment in emergency stop situations. With up to 300% higher capacity than traditional shock absorber designs, ACE’s SCS33 to SCS64 dampers enable true linear deceleration to protect machinery. An upgraded orifice design creates a higher capacity in a more compact size. These safety dampers are more suitable for applications on automatic transfer machines, robot systems and other applications where uncontrolled motion could result in damage or danger.
These safety dampers were recently chosen to provide extra insurance for a widely used linear module assembly. The Bosch Rexroth Omega modules feature drive components on the carriage, enabling a variety of configurations used especially for long strokes in either a vertical or horizontal position. In this particular module, there are three sizes with main body widths of 55, 85 and 120 mm and lengths to 5,500 mm. The repeatability and rigidity of this module make it well suited to long strokes with speeds to 5 m/sec and accelerations to 50 m/sec2.
However, some end users of this linear module system require extra insurance against runaway motion should an unforeseen emergency occur.
Due to the loads and speeds involved in many linear motion applications, the module’s design engineers wanted to create an optional industrial impact damper to protect the Z-axis against uncontrolled motion. Working together with ACE engineers, safety dampers were carefully designed over a nine-month period to work perfectly with the linear modules. Compared to standard hydraulic industrial impact dampers, ACE safety dampers were specifically designed for emergency use only. In this scenario, three load ranges from 20 to 90 kg, at impact speeds to 5 m/sec, had to be accounted for.
Several hydraulic safety dampers were considered. A slightly elevated impact speed was assumed in all cases to give the linear modules some flexibility. While the SCS33-50 impact damper with maximum energy absorptions of 620 Nm per stroke would have worked for the lower load ranges, the calculation showed that the larger SCS45-75 was needed to handle the higher moving mass (maximum 90 kg) for the 1,654.6 Nm per stroke. The result was that the linear modules were now more than capable of providing reliable service in an emergency.
Filed Under: Cylinders & Actuators