Patent attributes
A pedestrian pushbutton for activating a traffic device. A plunger mounted in a housing impinges on a piezo element when pressed. O-rings between the bolts that secure the plunger to the housing and the housing bias the plunger inwardly. A foam disk under the piezo element, or a resilient stem bumper on the back of the plunger, or both, bias the plunger outwardly with a force about equal to the inwardly biasing force of the O-rings on the bolts. Thus, the opposing resilient members maintain the plunger at neutral buoyancy when at rest. An O-ring disposed between the edge of the plunger and the opening in the housing centers the plunger. The pushbutton may include light and sound assemblies to confirm to the pedestrian visually and audibly that the pushbutton has been engaged. The sound chamber may be tuned based on the Helmholtz formula to achieve an optimum frequency.
