The Differences, Applications and Benefits of Trunnion Indexers
Motion's Lobby Display with a RT250 Drive
Differences
Trunnion Indexers are vertically mounted Rotary Index Tables designed for the unique purpose of creating a plane of rotation perpendicular to the floor. With this system, large sets of tooling can be mounted to simple box frames and rotated above the floor. This allows for multiple sets of tooling to be in place on a single frame (one set for each side), and turned in precise increments for use. Where a process may have previously required multiple stations, a trunnion can place all the necessary tooling in one place, saving significant amounts of floor space.
The physics behind a trunnion indexer are inherently different from those behind a standard configuration rotary table. Rather than the load capacity being dependent on the inertial loading and bearing capacities, a trunnion indexer’s capacity is usually dependent on its static torque output limitations. Here is a list of permissible static output torque values [Nm] for our line of rotary index tables:
| RT160 | RT200 | RT250 | RT400 | RT500 | RT630 | TT315 |
| 400 | 620 | 890 | 3250 | 7500 | 12600 | 2030 |
A properly designed, well balanced trunnion system is capable of moving significant weights at remarkable speeds. Since inertia in a trunnion configuration is exponentially dependent upon system balance, a properly engineered system is necessary for an efficient end product.
Applications
Trunnions can be applied to any number of applications, but they are most commonly used for mounting welding equipment, rotary positioning and the mounting and rotation of parts for assembly purposes. The same custom design elements that can be applied to Motion Index Drives’ RT Series can be applied to the indexer used in a trunnion configuration. Special coatings; continuous, oscillating or flexible modes of operation; custom index times and dwell periods; as well as reinforced cam followers for increased static torque capacities.
Benefits
Several benefits have already been outlined, such as the saved floor space and potential for managed high load capacities in a well engineered system. In addition to these, manufacturing costs of a trunnion system tend to be lower than a standard configuration rotary table. In a properly balanced system, trunnions can allow for drives and frames to be sized down when compared to standard configuration counterparts. As an added note, trunnion drives offer significantly higher accessibility for maintenance purposes, giving owners and operators the opportunity to perform easier maintenance checks and potentially extend the life of the indexer.
