ELECTRICITY GENERATION FOR PEDALLED VEHICLES

Abstract: A generator (3) mounted within the tread portion (2) of a pedal (20) of a bicycle or the like is driven via pulleys (4) and (5) of unequal diameter and a gear box (7) so that the speed of rotation of the rotor of the generator is a multiple of the speed of relative rotation between the spindle (1) of the pedal and the tread portion (2) when the latter is held horizontal by a foot resting on it and the crank (not shown) from which the spindle (1) extends is rotated to propel the bicycle. The gearing up of the generator enables sufficient output voltage to illuminate an array (9) of LEDs and charge a capacitor (8) which will keep then illuminated while the pedal is temporarily stationary.

Description: 1 "EaECTRICITY G.ENERATION FOR PED.ALLED VEHICLES" This .invention relates to electricity generation for pedalled vehicles and more particularly to improvements .in the generation of electricity by pedal power and its use .in contribut.ing to road safety. Pedalled vel-icles such as bicycles are particularly vulnerable to road accidents not only .because they offer little or no protection to the rider but pr.imarily .because the drivers of other vehicles may not see them, especially .in the dark or poor weather conditions. It is of course mandatoiry in most countries for bicycles to use lights .in the dark and most are equipped with reflectors, but conventional lighting systems leave much to be desired. If lighting is by dry .batteries these may fail or the rider may s.imply fail to turn them on. The drawbacks of convention^ generators, either .incorporated in a wheel hub or driven by a tyre, .include the fact tliat they make pedalling .harder, which is a disincentive to us.ing them, and tihat the illumination they provide ceases as scon as the bicycle stops, representing a considerable danger e.g. when the bicycle is waiting at traffic lights or at a road junction. Reflectors are of course only effective when illuminated by the oncoming vehicle, which will not occur if the latter has no adequate lights or is approactung at an angle. In recent years I^Ds (light emitting diodes) have .been used either instead of or to supplement light .bulbs. Taking advantage of the.ir relatively low power cor-sumption it is practicable to have them permanently in use, even in daylight. Flasliing .LEDs attract attention and it lias been appreciated that it is particularly advantageous to mount them upon the pedals. The.ir rotary motion attracts attention and moreover an oncoming driver can judge his orientation relative to the bicycle by whether the rotating .LEDs descr-Lbe a circle (when at right angles) a vertical line (when in front or .behind) or an elipse when approacήing at an angle. D.irection can of course .be judged by the colour of the visile .LEDs, usually red indicating the rear of the bicycle and a white or green light indicat.ing ttiat it is approaching. While the use of LEDs on the pedals of a bicycle is hlgHLy advantageous, if their power is derived from a dry battery th s may fail unbelmownst to the rider and in any event the use of dry batteries is undesirable if it can be avoided .both because of their high cost and the env^on ental problems associated with their disposal. Japanese Patent Publication No. 07291174A and United States Patent No. 5662405 propose the modification of a bicycle pedal to serve as a generator of electricity to illuπάnate LEDs mounted on the frame or tread portion of the pedal. Permanent magnets are attached to the pedal stiaft or sp.indle and the pedal frame or tread portion is provided with windings or solenoids and relative rotation .between the peπnanent magnets and the wirings as relative rotation occurs between the pedal sp.indle and tread portion generates current by magnetic induction on the same principles as .in the case of a conventional bicycle dynamo. The voltage generated by an inductance generator is a function of the number of Waincbngs of the stator and the speed of rotation of the rotor. The essential weakness of a system such as descr.ilDed .in the said Japanese patent publication resides in the relatively very low speed of rotation " of the rotor or spindle under normal circumstances. A pedal spindle will rotate only once relative to the tread portion or frame mounted upon it for every revolution of the crank on which the sp-indle is mounted. A cyclist typically will pedal at .between 30 and 60 revolutions of the pedal crank per minute. Jaι>anese Patent publication No. 07291174A recognises this problem but the only solution proposed is to increase the number of Wairidings. The present Applic-ants .have calculated that this is .impracticable because it would .increase unacceptably the cost and/or size of the stator component, .bearing in mind that this is to be inco.rporated in the tread portion of a pedal. .Another disadvantage of using the pedal sp.indle itself as the rotor is that it, and the associated .bearings, will .be subjected to the wear and abuse in service wliich pedal sp.indles usually ejperience. It is preferable that the relatively delicate and accurate bearings of a generator should not .be directly e.xposed to such treatment. A pr.incipal object of the present invention is to iπtprove upon the proposals of the said Japanese Patent publication and offer solutions to the problems associated therewith. In accordance with the .invention there is provided electricity generat.ing apparatus for a vetiicle equipped with pedals, such as a bicycle, where.in at least one said pedal comprises a spindle and a tread portion relatively rotatable about the spindle, electricity generat.ing means mounted upon the tread portion and transmission means .between the spindle and generator such that for each revolution of the spindle relative to the tread portion the generator undergoes more than one revolution. .Preferably the rotor of the generator is rotatably mounted within the tread portion to rotate about an axis generally parallel with t±at of the sp-indle and the generator preferably comprises stator means generally parallel with the sp.indle and stationary relative to the tread portion. The transmission means may drive the rotor of the generator via gears at one end of the generator stator. The transmission means may comprise mesl ng gear wheels of " unequal diameter one of which is stationary relative to the sp-indle and the other of which drives the rotor of the generator or it may comprise pulleys of unequal diameter one of which is stationary relative to the spindle and the other of which drives the rotor of the generator, said pulleys being connected by an endless .belt. The ratio of said gear wheels or of said pulleys is preferably of the order of 2:1. The said gears are preferably .included in a gear .box which lias a 5:1 output ratio. The generator and gear .box may be arranged in longitudijral alignment within the tread portion on one side of the sp-inidle and a capacitor may .be arranged within the tread portion on the opposite side of the sp.indle, the capacitor .be.ing arranged to store electricity generated by the generator. One or more arrays of ISDs may .be mounted on the tread portion and arranged to .be energised by electricity generated by the generator. .LEDs ej osed to view at one side of the tread portion may differ from .LEDs ejposed at the opposite side of the tread portion and the weight of the tread portion may .be different on opposite sides of the spindle such that it adopts a non- ϊiorizontal attitude .before a foot is placed upon it. Alternatively, or in addition, the underside of the tread portion may .have an outward projection. In t ή is way a cyclist can detei ne whether a pedal tread portion is the right way round or not (i.e. to offer the correct LED displays in the correct directions) when pu.tt.ing a foot on it. The said difference b.etween the L.EDs may be one of colour, number, distr.ibution or any combination of these. The arrangement is preferably such that the generator lias an output of approximately 2 volts when relative rotation between the spindle and tread portion is 30 rpm. A preferred embodjjnent of the invention will now be described with reference to the accompanying Drawings, .in which: Figure 1 is a longitudinal section tήrough a bicycle pedal assembly .in accordance with the present invention, Figure 2 is a sectional elevation taken on the l.ine II-II of Figure 1, and Figure 3 is a sectional elevation taken on the l.ine III-III of Figure 1. The bicycle pedal 20 illustrated in Figure 1 is designed to extend at one end 21 from a crank (not shown) of a bicycle. .As is well .known per se the bicycle lias a second crank s.imilarly equipped with a pedal at 180° to the f-irst, and by placing one foot on each pedal and rotat.ing the cranks the cyclist propels the machine. The pedal comprises a sliaft or spindle 1 which will be stationary relative to the associated crank and upon which is mounted a frame or tread portion 2 to .be relatively rotatable by means of bearings 22 and 23. With a cyclists' foot rest.ing on it the tread portion 2 will be held in a .horizontal attitude and so for each full revolution of the crank there is one full revolution of the sp.indle 1 relative to tread portion 2. As so far descr-Uoed the pedal 20 is conventional so that no further description is considered necessary. In accordance with the present invention, however, there is disposed at the distal end of the spindle 1 and stationary with respect thereto a pulley 4 which is connected by an endless b.elt 6 to a smaller pulley 5 with a ratio of 2:1. The pulley 5 is at one end of and drives the gears of a gear box 7 which in turn drives the rotor of a generator 3, the gear box having the effect that the rotor of the generator 3 is rotated at five times the speed of the pulley 5. The assembly of gear lxjx 7 and generator 3 is a proprietary product readily available on the market so tήat no further description thereof is considered necessary. It is .housed within the tread 2 on one side of the sp.indle 1. Housed in the tread 2 on the opposite side of the spindle is a capacitor 8 which is arranged to store electricity generated by the generator 3 so as to continue to energise an array 9 of LEDs, if for only a short t:Lme, after the generator ceases to rotate either because the bicycle is stationaiy or because the cyclist is free-wheeling. It will be seen tnat by this arrangement for each full rotation of the crank, and with the tread 2 held horizontal by a foot placed upon its upper surface 14, there will be one full revolution of the pulley 4 relative to the tread 2 and in consequence the rotor of the generator will be rotated at a speed wliich is a multiple of the speed of rotation of the crank, typically 300 .rpm when the rate of rotation of the crank is between 30 and 60 rp . A speed of rotation of the rotor of the generator of 300 rpm is sufficient to output 2 volts or more, tnis .being the .πiiiiirπum required simultaneously to energise the LEDs 9 and charge the capacitor 8. The array 9 of LEDs mounted on a circuit board 10 is housed in a lens 13 at the distal end of the pedal tread portion 2 and mirrored surfaces 12 witlύn the lens are arranged to project light beams in the fore and aft direction Where there is no mirrored surface opposite an LED its light beam is projected laterally outwardly of the bicycle. In a modification which is not illustrated the mountings of the mirrored surfaces 12 .instead of .be.ing integral with the material of the lens are free to rotate relative thereto and are eccentrically weighted so that the respective mirrored surface will maint^-in the same attitude .irrespective of the angular position of the pedal. In this way they will project light beams .in the fore and aft direction regardless of the pedal orientation. The light emitted rearwardly may be red and the light emitted forwardly and laterally may be of a different colour, such as wϊiite, so that the drivers of other vehicles will Jσiow in which direction the bicycle is travelling. To prevent placing a foot on the pedal with the tread the wrong way round (i.e. so tliat red light shows forward) the pedal has a projection 15 on its underside which will alert a rider if he places his foot on it and/or the assembly 3,7 is of greater weight than the capacitor 8 so tnat the pedal assumes a non-horizontal attitude when there is no foot upon it. .Preferably the heavier assembly 3,7 is in the rear section 11 of the pedal so tliat the pedal will tilt backward. When mount.ing the bicycle the rider will .know tliat the pedal should be tilt.ing .backward rather than fo.rward .before placing a foot upon it. Pedals according to tnis embod.iment will .be supplied .in pairs, the two pedals of each pair having oppositely-handed screw threads for engagement with the cranks so tliat they cannot .be fitted the wrong way round. It will be evident tliat both pedals of the same bicycle or other pedal driven or pedal equipped vehicle may s.imilarly be provided with electricity generataing and/or capacitor and/or .LED means. It will also .be evident tliat the electricity generated by the generator 3 might be used .instead or additionally to energise some other device such as a sonic alarm. The present invention provides for the first t.ime a practicable way of aclιiev.ing that a bicycle or the l.ike will .be provided with a lighting or other alarm or ale.rt.ing system which does not rely either upon batteries or upon the rider remenibering to .switch it on. The system is an .in-.built and foolproof safety feature which could be made mandatory for bicycles without unacceptably .increasing thei cost or having .implications for the environment .such as arise from the use of batteries. A further advantage is that pedals according to the .invention may .be offered as replacement or "retro fit" items, so tliat exist.ing macnines can be equipped with them at little cost as well as new ones.

Claims: CLAIMS : 1. Electricity generat.ing apparatus for a vehicle equipped with pedals, such as a bicycle, wherein at least one said pedal (20) coπprises a spindle (1) and a tread portion (2) relatively rotatable about the sp.indle (1), characterised in tliat electricity generating means (3) is mounted upon the tread portion (2) and .in tliat transmission means (4,5,6,7) is provided .between the sp.indle (1) and generator (3) such tliat for each revolution of the spindle (1) relative to the tread portion (2) the generator (3) undergoes more tήan one revolution. 2. Apparatus as cla.imed in claim 1, characterised in tnat the rotor of the generator (3) is rotatably mounted within the tread portion (2) to rotate about an axis generally parallel with tliat of the spindle (1). 3. .Apparatus as cla-Lmed in either preceding clam, characterised in tliat the generator (3) comprises stator means generally parallel with the -spindle (1) and stationary relative to the tread portion (2). 4. Apparatus as claimed in any one of the preceding claims, characterised .in ttiat the transmission means (4,5,6) drives the rotor of the generator (3) via gears (7) at one end of the generator (3) stator. 5. .Apparatus as claimed in any one of the preced-Lng claims, characterised .in that the transinission means (4,5,6,7) comprises meslύng gear wheels of unequal diameter. 6. Apparatus as claimed .in any one of the preceding claims, cliaracterised in tliat the transmission means (4,5,6,7) comprises pulleys (4,5) of unequal diameter one (4) of which is stationary relative to the sp.indle (1) and the otlier (5) of wliich drives the rotor of the generator (3), said pulleys (4,5) be.ing connected by an endless .belt (6) . 7. Apparatus as claimed in claijn 5 or claim. 6 characterised .in that the ratio of said pulleys (4,5) is of the order of 2:1. 8 8. Apparatus as claimed in claim 4, or any of claims 5-7 as appendant to claim 4, characterised in tliat the gears are included .in a gear box (7) which has a 5:1 output ratio. 9. Apparatus as cla.imed in clam 8, characterised in that the generator (3) and gear .box (7) are arranged in longitud.inal alignment witlun the tread portion (2) on one side of the spindle (1) and a capacitor (8) is arranged witlύn the tread portion (2) on the opposite side of the sp.indle (1), the capacitor (8) .being arranged to store electricity generated by the generator (3). 10. Apparatus as claimed in any one of the preced.ing claijns characterised in tliat it comprises one or more arrays of LEDs (9) mounted on the tread portion (2) and arranged to .be energised by electricity generated by the generator (3). 11. Apparatus as claimed in claim 10 characterised in tliat said LEDs (9) are mounted witliin a lens (13) at the end of said pedal (20) which in use is remote from the associated crank and further diaracterised JLn tliat mirrored surfaces (12) are provided within said lens (13) arranged to project light from selected ones of said LEDs (9) in the fore and aft direction. 12. .Apparatus as claimed in cla 11, characterised in tliat said .mirrored .surfaces (12) are mounted within tlie lens (13) so as to be freely rotatable and each is eccentrically weighted so as to tend to retain the same attitude .irre.spective of the angular orientation of the pedal (20). 13. .Apparatus as claimed .in any of cla-lms 10-12 as appendant to claim 9, diaracterised in that L.EDs (9) ejposed to view at one side of the tread portion (2) differ from LEDs (9) ej osed at the opposite side of the tread portion (2) and in tliat means (15) is provided to encourage the selection of a particular orientation of the pedal (20) when a foot is placed upon it. 14. Apparatus as cla.imed in claJLm 13 characterised in tliat the said difference is .in colour, number and/or distr-Lbution. 15. Apparatus as claimed in claim 11 characterised .in tliat the weight of the tread portion is different on opposite sides of the sp.indle (1) such that it adopts a non-horizontal attitude before a foot is placed upon it. 16. Apparatus as cla.imed .in any one of claims 11 - 15, characterised .in that the underside of the pedal (20) has a projection (15). 17. Apparatus as claimed in any one of the preced.ing cla.ims characterised in that the arrangement is such that the generator (3) has an output of approximately 2 volts when relative rotation between the sp.indle (1) and tread portion (2) is 30 rpm.

Inventors: HICKS RICHARD BANFIELD, HICKS, RICHARD, BANFIELD
Applicants: PEDALITE LTD, PEDALITE LIMITED
Application year: 1999
Main classification: B62J6
IPC codes: B62J3, B62J6, B62M3, H02K7, H02K11, H02P9