Device for generating electricity by pedestrian and vehicular traffic

Energy expended by pedestrian or vehicular traffic is captured by a device which includes a plurality of tread plates which when depressed by traffic thereupon drive rocker arms mounted by one way clutches on a shaft. The rocker arms are spring biased upwardly to keep the tread plates normally raised so that the tread plates return to their initial position after being depressed. Preferably, the shaft is connected to a generator, and the generator to a battery so as to store electrically the energy captured mechanically. By using the aforedescribed configuration a relatively thin device is achieved which can be conveniently installed under a carpet and used in the doorways of buildings or other heavy traffic areas.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to an apparatus for generating electricity, and more 
particularly, this invention relates to apparatus for generating 
electricity by application of gravitational forces due to traffic from 
pedestrians or rolling vehicles. 
2. Prior Art and Other Considerations 
A great deal of energy is expended by and thus available from traffic, such 
as traffic from pedestrians or rolling vehicles. Generally, this energy is 
not recouped and put to useful purposes because to date, there are no 
viable devices for capturing this energy. Pedestrian traffic on city 
streets or in the entrances and exits of buildings is considerable, and in 
view of the growing scarcity of energy, tapping that energy so as to 
recoup some portion of it is one way to save or redirect available energy. 
U.S. Pat. No. 3,944,855 discloses a device for tapping such an energy 
source, however, the device requires a considerable amount of vertical 
room and is therefore not readily adaptable to existing structures. 
Furthermore, the device does not provide a mechanism for continuously 
applying torgue to a generator while a pedestrian or vehicle traverses the 
device. 
Accordingly, there is a need for an apparatus which lends commercial 
viability to the concept of tapping energy made available through the flow 
of pedestrian and vehicular traffic. 
SUMMARY OF THE INVENTION 
In view of the foregoing considerations it is an object of the instant 
invention to provide new and improved apparatus for recouping energy 
expended by traffic flow. To this end, the instant invention contemplates 
a support for carrying tread plates, rocker arms and a torque transmitting 
shaft wherein the tread plates absorb forces created by traffic flow and 
transmit forces through the rocker arms to the shaft. Preferably, the 
shaft transmits the forces in the form of torgue to an electric generator.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT 
Referring now to FIG. 1, there is shown an apparatus 10 in accordance with 
the instant invention wherein a plurality of tread plates 11, are arranged 
in a pair of rows and contained in a low profile unit for installation in 
heavy traffic areas such as the entrances and exists of department stores 
and buildings. Preferrably, the apparatus 10 is self-contained and 
includes an electric generator which is connected to exterior circuitry by 
leads (not shown), or the like, extending from the apparatus. The leads 
are connected to a battery charger (not shown) so as to store electricity 
for general use or for specialized situations such as power failures. 
Preferrably, the apparatus 10 is covered with a plastic sheet 12 to keep 
out dirt and has a profile low enough so that it can be inserted beneath a 
carpet 13 without being particularly obtrusive. Ramps 14 are provided at 
each end of the apparatus 10 so as to provide a smooth contour for the 
apparatus. 
Referring now to FIGS. 2-5, there is shown in FIG. 2 a channel section 20, 
which serves as a support member for a plurality of the tread plates 11. 
The channel 20, has a bottom plate 21, and a pair of upright side plates 
22, which join a pair of top flanges 23 to the bottom plate to form an 
enclosure. The tread plates 11 have spaced tabs 25, thereon which are 
received in spaced, opposed slots 26 cut in the flanges 23, so as to 
pivotally support the tread plates. A plurality of U-shaped bearing boxes 
27 are contained within the channel 20 beneath the top flanges 23. The 
bearing boxes 27 have a shaft 28 journaled therethrough and having axes of 
rotation extending in the same direction as the direction of traffic flow. 
The shaft 28 is used to transmit torque to a generator, as will be 
explained hereinafter. Each bearing box 27 has a rocker arm 30 mounted 
therein and secured to the shaft 28 by a one-way clutch 31. The one way 
clutch may be of the roller-ratchet type such as the roller-ratchet clutch 
52 shown in U.S. Pat. No. 1,916,873 issued to E. B. Wiggins on July 4, 
1933. The one-way clutches 31 engage when the rocker arms 30 pivot in one 
direction and disengage when the rocker arms pivot in the opposite 
direction to let the rocker arms 30 return freely to the raised position. 
Each rocker arm 30 is biased to a raised position by a spring 33 which has 
one tail 34 resting on the bottom of the bearing box 27 and a second tail 
35 received in an opening 36 in the rocker arm. 
As seen in FIG. 5, each tread plate 11 has its free end 37 resting on a 
rocker arm 30, which rocker arm projects through a space 38 between the 
tabs 25, of the next tread plate 11. When a person steps on a tread plate 
11, the tread plate moves from its raised position shown in FIG. 5 to a 
relatively flush lower position causing the rocker arm 30 to move from its 
raised position to its lowered position. The one-way clutch 31, engages as 
the rocker arm moves from its raised to its lower position thereby 
rotating the shaft 28. When the person's foot moves off the tread plate 
11, the spring 33 rotates the rocker arm to its raised position thereby 
raising the tread plate 11 to its raised position so that a subsequent 
foot step can depress the tread plate and turn the shaft 28 further. Since 
there are a plurality of plates 11, the shaft 28 will tend to rotate 
continuously as a pedestrian walks along the unit 10. Accordingly, a 
generator connected to the shaft 28 will continuously generate electrical 
power. Preferrably, a battery charger is connected to the generator so as 
to charge a battery and store energy as traffic moves along the apparatus. 
FIGS. 5, 6, and 7 show a proposed commercial application of the preferred 
embodiment wherein a generator 40 is connected to a pair of parallel 
shafts 28 via a train of gears 41 which gear down the torque in shafts 28 
and provide a high speed input to the generator. As seen in FIG. 8, the 
generator and gear train are disposed between a pair of channels 20 
arranged in parallel which mount parallel rows of tread plates 11 in the 
manner shown in FIG. 1. The shafts 28 are geared by miter gears 44 to a 
transverse shaft 45 which in turn is geared by a mitor gear 46 to an input 
shaft 47 of the gear train 41. In this way, a relatively compact torque 
transmitting arrangement is achieved having a high speed output. 
As seen in FIG. 6, the generator 40 is configured with a low profile and 
the gear train 41 has the gears arranged in a horizontal array with axes 
perpendicular to the tread plates 11 to also provide a low profile. 
Accordingly, both the gear train 41 and generator 40 can be contained 
within the thin unit 10 shown in FIG. 1. The gear train 41 converts the 
relatively low speed and high force applied to shaft 28 and through shaft 
45 to a high speed rotation in generator 40, which rotation is maintained 
due to the inertia of the device even when there is relatively 
intermittent force applied to the tread plates 11 of the unit 10. 
Due to the relatively high impulse necessary to impart starting torque to 
the generator, it is preferable to include a spiral spring 50 between the 
gear train 41 and rotor 51 of the generator 40. As is seen in FIG. 10, the 
rotor 51 is fixed to a shaft 52 on which a rotor disc 53 is also fixed. 
The shaft 52 is journalled in casing 55 which contains the generator 40 
and gear train 41 so as to rotate freely in the casing. The gear train 41 
ends with a pinion gear 58 which is freely rotatable on the shaft 52 and a 
fly wheel 60 is fixed to the pinion gear and also freely rotatable on the 
shaft. The spring 50 has one end 63 fixed to the fly wheel 60 and the 
other end 64 fixed to the rotor disc 53. 
Upon applying torque to the fly wheel 60 by pinion gear 58, the spring 50 
is wound to the point where the force stored therein exceeds the force 
necessary to overcome the moment of inertia of the rotor 51 at which time 
the rotor begins to turn. Consequently, the high torque necessary to start 
rotation of the rotor is created by storing energy in the spring 50 until 
sufficient energy is available. 
The foregoing embodiment is merely illustrative of the invention which is 
to be limited only by the following appended claims.