Gravity Light - Concept
Conceptually interesting? yes.
Realistic? ……
Concept
Final mock of PC shell & SS tie-down rings
The goal of this concept is to create a sustained light source for ~15 mins that can be generated with gravitational potential energy as the input.
The device is held up by the SS tie-down rings wrapped around a tall object say a rafter or a tree branch. Three meters of the cord is wrapped around the “Rope_Hub” that is pulled out slowly by a user sitting in a hammock bag attached to the said cord - this is the input torque. When the user’s mass is applied the centripetal force of the rotating drum causes the “fingers” to fly out and engage the “finger gear hub” causing the spur gears to spin and ultimately the generator. It is the resistive torque of this generator (that generates electricity), mass moment of inertia forces, and frictional forces of the system that ultimately resist the user’s input mass. Eventually, the cord will be spent at some time and the system must be reset. When the user’s mass is removed the fingers fall back inwards and the torsion spring which has been wound up during the previous step now retracts the cord and hammock bag allowing the whole system to cycle again. All rotating components (gears, rope_hub…etc) are constrained by snap rings and run on oil-embedded sleeve bearings.
Can see the centripetal fingers that engage/disengage the drum
In reality, the variance of human body weight between users would quickly swing the usable ‘on time’ of the light between too short and not heavy enough to begin the mechanism. Would be better to just have a rope to pull that would wind a spring and store the potential energy instead.