1. Field of the Invention
This invention relates generally to actuators for ergonomic systems and, more particularly, to actuator systems for seat adjustments.
2. Related Art
Ergonomic supports for seats, such as lumbar and bolster systems, are typically moved by means of actuators that can be operated by hand or driven by a motor. Four-way power lumbar devices, with an arching mode and a translation mode, have traditionally required a motor for each mode of operation. In comparison, the invention set forth by U.S. Pat. No. 6,050,641 is a four-way power lumbar system that requires only a single-motor and reduces the duplication of gearbox components. Prior to this invention, U.S. Pat. Nos. 5,197,780 and 5,217,278 had only described four-way lumbar devices that were manually operated by a single control knob.
While these devices are an improvement over the conventional four-way lumbar devices that required multiple motors or multiple control knobs, the highly competitive markets for furniture and automotive seats place a premium on continued optimization of devices that provide comfort and convenience for seat occupants. In particular, there is a need for improved actuation systems that are less prone to failures and more efficiently transfer power to the actuators. For example, with regard to the manually-operated four-way lumbar systems, the gearing systems are inefficient because, in addition to the gears, they have a transmission that requires at least one non-gear alignment device to maintain the proper engagement between the driver gear and the driven gears. Therefore, such devices have an alignment device that is necessary for the convenient operation of the lumbar system and increase the potential for a failure in the system.
Additionally, there is a need for actuation systems that are more modular, increasing the commonality of parts between two-way and four-way power lumbar devices, manually-operated and motor-driven actuation systems, and lumbar systems and bolster systems. For example, the prior art actuation units and driven gears are designed to fit within a single housing along with the driver gears and the transmission system, thereby limiting the range of motion that is capable for the actuation units themselves. Different types of lumbar devices and bolster devices are typically designed to provide different levels of support and often require different levels of actuation, thereby affecting the size of the actuators. The prior art devices do not easily allow for changing the actuators according to various sizing requirements, and the confined housing could prevent the same actuation system from being used for different lumbar devices or for a lumbar device and a bolster device. Therefore, entirely different actuation systems would need to be designed, and separately manufactured, depending on the actuators' usage, range of motion, and sizing.