US Patent 7633000 U-joint for double pedal

A drum pedal assembly for connecting a first pedal to a support holding a beater arm may include a telescoping transmission shaft having yokes attached to shaft ends, yokes having bosses, universal joints rotatably attached to bosses and using trunnions, second yokes having bosses attached to universal joints using additional trunnions. The second yokes may rotatably attach a drive assembly rotatably attached to first pedal and an attachment arbor attached to beater arm to facilitate rotation of beater arm when first pedal is depressed. Configuration of assembly, including that of universal joints, may help reduce backlash or vibration in assembly.