GB2413016A

GB2413016A - Electric generator for operation by passing vehicles.

Info

Publication number: GB2413016A
Application number: GB0426098A
Authority: GB
Inventors: Maurice Raymond Mclaren; Robert Taylor
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-04-08
Filing date: 2004-11-24
Publication date: 2005-10-12
Anticipated expiration: 2024-11-24
Also published as: GB2413016B; GB0408031D0; GB0426098D0

Abstract

An electrical generator 16 mounted in a housing 10 detachable from the traction housing 4 is driven via gearing 14 and optional one way clutch 15 by a traction roller 6 mounted in a road surface for continuous rotation by passing vehicles. Elements 12 rigidly secure the housings together and a grease filled seal formed by cups 35,36 mounting lip seal elements is provided. Grease may be added to cavity 40 via bore 47 and the apertures 41 in the housing walls may be elongate so as to permit removal of the shaft 7 and roller 6 in situ.. The roller may be replaced by an endless belt and the housing 10 may be detachable. Generators may be provided at each end of the roller. The system supplies load 24 and charges a battery bank 21 via a charge controller 20. The generator may be used to power street lighting, traffic lights, road signs etc. or for recharging stations for electric-powered vehicles, etc..

Description

ELECTRICAL GENERATOR FOR OPERATION BY PASSING

VEHICLES

TECHNICAL FIELD OF THE INVENTION

This invention relates to an electrical generator for operation by passing vehicles.

BACKGROUND

Various electrical generators for operation by passing vehicles have previously been disclosed. A common form of generator uses the weight of passing vehicles to depress a pressure plate and/or pump a fluid, which is in turn used to drive an electricity generating device via a suitable intermediate mechanism. In general, such generators are only capable of recovering a limited amount of energy from a moving vehicle which only makes contact with the device for a small fraction of a second. The pressure plate must also be restored to its starting position after passage of a vehicle so that there is a finite recovery time which further limits the amount of energy which can be recovered.

It is also known to use an endless traction surface such as a belt or roller which is moved by the wheels of passing vehicles. Such devices are - 2 capable of rotating substantially continuously so that they are capable of providing a continuous output torque which may, in turn, be used to drive an electricity generating device. One problem with such devices is that it is difficult to prevent surface water from reaching the electrical part of the installation, necessitating frequent maintenance and repair. This is expensive in terms of parts and labour, and is also inconvenient, involving serious disruption to traffic flow.

It has been proposed to mount the generating devices separate from the traction section of the device at the side of a roadway, but this requires complex and expensive drive arrangements which may themselves be prone to failure under heavy traffic. When such failures do occur the disruption to traffic may be even greater.

The present invention seeks to provide a new and inventive form of electrical generator for operation by passing vehicles which is reliable and capable of operating for long periods without intervention, and which can also be serviced with minimum cost and disruption to traffic flow when necessary.

SUMMARY OF THE INVENTION

The present invention provides an electrical generator for operation by vehicles travailing along a road surface, which includes: - a traction housing containing a traction member having a traction surface for mounting generally coplanar with the road surface and which is arranged such that the traction surface can move continuously in a direction opposed to the direction of travel of the vehicle whereby a vehicle travailing over the traction surface moves the traction member; - 3 - a waterproof housing containing an electricity generating device, and which is rigidly connected to the traction housing by releasable coupling means, the traction member being operably coupled to the electricity generating device via drive means which passes through the walls of both housings.

The drive means may comprise a shaft which passes through the walls of the housings and enters the waterproof housing through a seal assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

The following description and the accompanying drawings referred to therein are included by way of non-limiting example in order to illustrate how the invention may be put into practice. In the drawings: Fiqure 1 is a general view of an electrical generator in accordance with the invention, installed in a road surface for operation by a passing motor vehicle; Figure 2 is a side view of the electrical generator, partly sectioned; Figure 3 is a plan view of the generator; Finure 4 is an end view of the generator, partly sectioned; Fiqure 5 is a section through the sealing arrangement between the two housings of the generator; - 4 Finure 6 is a transverse sectional view of the sealing arrangement; and Figure 7 is a schematic diagram of the electrical generator.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring to Fig. 1, an electrical generator 1 is installed in a road surface 2 for operation by a motor vehicle 3.

The generator is shown in more detail in Fig.s 2, 3 and 4, and includes an elongate traction housing 4 having a removable top plate 4a with a rectangular opening 5. A traction roller 6, fixedly mounted on a shaft 7, is supported inside the housing and rotatably journalled in self-aligning bearings 8 and 9, which are removably fixed to a heavy duty support structure 30 by bearing housings 31. The roller has a cylindrical external traction surface 11, of rubber, polymer or other friction material, which substantially fills the opening 5, lying substantially co- planar with the top plate 4a of the housing.

One end of the shaft 7 passes through the end wall of the housing 4 into a waterproof generator housing 10 having a removable top plate 1 Oa with a suitable sealing gasket. The generator housing 10 is releasably connected to the drive housing 4 by heavy duty waterproof fasteners 12, such as bolts with copper washers and acorn nuts. The two housings are thus prevented from moving relative to each other. Inside the generator housing 10, the shaft 7 is drivingly engaged with an electricity generating device 16 via a gear train 14 and an optional unidirectional clutch 15. The electricity generating device 16 may be an alternator, dynamo or other - 5 rotor-and-stator type device.

The fasteners 12 directly clamp together the opposing walls of the housings 4 and 10, preferably with a sealing gasket sandwiched between the walls, surrounding the shaft 7. As shown in Fig. 5, the shaft 7 passes through a seal assembly which comprises a pair of plates 35 and 36 secured on opposite sides of the opposing walls, e.g. by bolts inserted through holes 37. Sealing gaskets may be interposed between the plates and the housing walls. The opposed inside faces of the two plates 35 and 36 each have an annular recess 38 to receive a water seals 39. The two seals 39 bound a grease cavity 40 formed by enlarged and slightly elongated apertures 41 through which the shaft 7 is inserted. The slightly elongate shape of the apertures 41 enables the shaft 7 and roller 6 to be removed from and inserted into the traction housing 4 while the housing remains in situ. Each of the seals 39 comprises an outer lip seal 44 with a V-shaped groove on its inner face in which a wedge-section pressure ring is inserted. The cavity 40 may be filled with grease via a duct 47 formed by a drilling in either of the opposed housing walls. The pressure of grease within the cavity 40 thus urges the pressure rings 45 against the lip seals 44 causing the lip at the radially inner edge of the V to bear against the shaft 7 and the radially outer lip to bear against the outer surface of the recess 38.

It is important that during assembly of the generator the plates 35 and 36 should be accurately aligned so that they do not cause the shaft to bind or impair operation of the water seal assembly. The outer faces of the plates are therefore formed with annular recesses 50 to receive axially split collets which centre the shaft relative to the plates. Once the plates are secured by the bolts inserted through holes 37 the collets can be removed allowing the shaft to rotate freely. - 6

When cars or other motor vehicles pass over the generator 1 the vehicle tyres briefly engage the traction surface of the roller 6 and impart rotational movement to the shaft 7, which thereby drives the generating device 16. With forward movement of the vehicle 3, rotation of the wheels in direction A imparts an opposite rotational movement to the friction roller 6 in direction B. In moderately heavy traffic, the friction roller continuously rotates in direction B to provide a substantially constant electrical output from the generating device 16.

As shown in Fig. 5, the electrical output from the generator 1 is fed to a charge controller 20 which supplies a constant charging current to a battery bank 21, which may be rated at any suitable voltage. The batteries store the electrical power to provide a constant electrical output even during periods when no vehicles are passing. The electrical components may all be housed within the waterproof box 4.

If the electricity generating device 16 generates a direct current, any vehicle which passes over the device in a reverse direction is prevented from reverse-charging the battery bank by the unidirectional clutch 15.

Other means of preventing reverse operation may be used such as a ratchet arrangement for the roller or by connecting a rectifier arrangement in the output of the generating device. However, devices which provide an alternating current output may operate in both directions.

The generator may be used to provide power in remote locations, or anywhere where an independent power source is required for any kind of consumer unit 24, e.g. street lights, traffic signals, illuminated road signs, etc. - 7 The generator is also particularly suitable for use in charging stations for electric vehicles or pickup points for replacement vehicle batteries. Ideal locations include motorway service areas, city centre car parks and airport car parks.

Larger generators may be constructed with multiple rollers driving separate or a common electricity generating device via respective clutches.

Since the electricity producing equipment is enclosed in a separate housing from the traction roller 6 different kinds of electricity generating device can be used with a standard drive unit. The advantages are as follows: a. The power section is kept dry.

b. Alternative power generating devices can be used with a standard drive unit.

c. The power section can be separately ventilated to remove heat.

d. The power unit can be removed separately from the traction housing for repair or modification.

e. Power generating devices could be mounted at both ends of the drive unit drivingly connected to the traction member, e.g. to satisfy different voltage requirements.

f. Should local requirements change the generator unit can easily be changed while the traction roller housing remains in situ.

g. No special measures are required to prevent entry of water into the traction roller housing.

It will be appreciated that the features disclosed herein may be present in - 8 any feasible combination. Whilst the above description lays emphasis on those areas which, in combination, are believed to be new, protection is claimed for any inventive combination of the features disclosed herein.

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Claims

1. An electrical generator for operation by vehicles travailing along a road surface, which includes: - a traction housing containing a traction member having a traction surface for mounting generally coplanar with the road surface and which is arranged such that the traction surface can move continuously in a direction opposed to the direction of travel of the vehicle whereby a vehicle travailing over the traction surface moves the traction member; - a waterproof housing containing an electricity generating device, and which is rigidly connected to the traction housing by releasable coupling means, the traction member being operably coupled to the electricity generating device via drive means which passes through the walls of both housings.

2. An electrical generator according to Claim 1 in which the drive means comprises a shaft which passes through the walls of the housings.

3. An electrical generator according to Claim 2 in which the shaft enters the waterproof housing through a seal assembly.

4. An electrical generator according to Claim 3 in which the seal assembly includes a cavity through which the shaft passes andwhich is packed with grease, and a pair of ring seals which bound the cavity surrounding the shaft.

5. An electrical generator according to Claim 4 in which each ring seal comprises a sealing lip which is urged into contact with the shaft - 10 by pressure of grease within the cavity.

6. An electrical generator according to Claim 4 or 5 in which the ring seals are received in recesses in respective plates secured on opposite sides of the cavity.

7. An electrical generator according to Claim 4, 5 or 6 in which the cavity communicates with a grease duct through which the cavity may be filled with grease.

8. An electrical generator according to Claim 7 in which the grease duct is formed in the wall of the waterproof housing.

9. An electrical generator according to any preceding claim in which the cavity is at least partially formed by an aperture in the wall of the waterproof housing.

10. An electrical generator according to Claim 9 in which the aperture is of elongate shape.

11. An electrical generator according to any preceding claim in which opposing walls of the two housings are sandwiched together with an intervening sealing gasket.

12. An electrical generator according to Claim 11 as appended to any of Claims 4 to 10 in which the cavity is partially formed by an aperture in the wall of the traction housing.

13. An electrical generator according to Claim 12 in which the aperture in the wall of the traction housing is of elongate shape.

14. An electrical generator according to Claim 12 or 13 as appended to Claim 7 in which the grease duct is formed in one of said opposing walls.

15. An electrical generator according to any preceding claim in which the traction surface is endless.

16. An electrical generator according to Claim 15 in which the traction surface is provided by a substantially cylindrical surface of the traction member.

17. An electrical generator according to any preceding claim in which the traction member drives the electricity generating device via a unidirectional clutch.

18. An electrical generator according to Claim 17 in which the unidirectional clutch is contained within the waterproof housing.

19. An electrical generator according to any preceding claim in which the electricity generating device provides electrical power to charge a battery bank.

20. An electrical generator according to Claim 19 in which the battery bank is contained within the waterproof housing.

21. An electrical generator according to Claim 19 or 20 in which the electricity generating device provides electrical power to the battery bank via a constant current charge controller. - 12

22. An electrical generator according to Claim 21 in which the constant current charge controller is contained within the waterproof housing.

23. An electrical generator according to any preceding claim which is installed in a recharging station for electric-powered vehicles.

24. An electrical generator according to any preceding claim in which two power generating devices in separate housings are mounted at opposite ends of the traction member housing both drivably connected to the traction member.

25. An electrical generator for operation by vehicles travailing along a road surface which is substantially as described with reference to the drawings.

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