Usability of a Compliant Deltoid Mechanism as a Motion Transmission in Civil Engineering Machinery

Recent advances in battery and actuator technologies enable their use in various small- and mid-sized devices in civil engineering. The principle of operation of most devices in civil engineering is based on rotary motions originating from combustion engines that are converted to linear motions via slider cranks. These relatively high-revving combustion engines require the use of a transmission in order to achieve lower frequencies on the output which is a necessity in most applications, e.g. for ground compacting vibrating tampers, which need tamping frequencies of about 16 Hz. The use of linear actuators or plunger coils bear the potential of reducing the number of parts while enhancing the efficiency. For the use of linear actuators different mechanisms can be utilized. This paper describes the classical slider crank for converting rotary into linear motions and two mechanisms for use with linear actuators or plunger coils, the double slider mechanism and the deltoid mechanism. All three mechanisms are described and analyzed. The deltoid mechanism is selected to be used in a demonstrator. The mechanism’s links and hinges are simplified using a compliant structure design. This compliant design and its construction and calculation process is described. The demonstrator is then built up and tested measuring its linear motion optically.