WO2009006704A1

WO2009006704A1 - Drive mechanism

Info

Publication number: WO2009006704A1
Application number: PCT/AU2008/001026
Authority: WO
Inventors: Manuel Vieira Barreiro
Original assignee: Barreiro Technologies Pty Ltd
Priority date: 2007-07-11
Filing date: 2008-07-11
Publication date: 2009-01-15
Also published as: EP2215358A1; JP2010534796A; AU2008274823A1; WO2009006704A9; AP2010005149A0

Abstract

A apparatus in the form of a torsional propulsion device functioning as an engine (10) for delivery of sustained mechanical power over an extended duration with only intermittent energy input. The engine (10) comprises an input shaft (11), an output shaft (13) and a drive mechanism (40) therebetween. The drive mechanism (40) comprises a drive gear (45), an input mechanism (71), and a spring mechanism (73) operably connected to the drive gear 45. The spring mechanism (73) is adapted to be loaded by the input mechanism (71) during the loading event. The loaded spring mechanism (73) is adapted to rotate the drive gear (45) in a driving direction during a driving event, the driving event being of a duration exceeding that of the loading event. The duration of the driving event is significantly greater than the duration of the loading event such that the drive mechanism (40) can deliver output energy for an extended duration as compared to the duration of energy input. Typically, the duration of the driving event is of at least an order of magnitude greater than the duration of the loading event.

Description

Drive Mechanism

Field of the Invention

This invention relates to a drive mechanism and to apparatus incorporating such a drive mechanism.

One particular application of the drive mechanism according to the invention is in apparatus capable of sustained delivery of mechanical energy with intermittent energy input. Such apparatus may, for example, operate as an engine for delivery of mechanical work for an extended duration in comparison to the duration of energy input into the engine.

Background Art

With a typical engine, input energy is delivered to the engine in a substantially constant manner for conversion into output energy (in the form of mechanical work). By way of example, in the operation of an electric motor, input electrical energy is delivered continuously to the motor for conversion into output energy in the form of mechanical work.

There are circumstances where it is desirable to have an engine which can provide a sustained energy output with only intermittent energy input. One such circumstance is where an engine is required to drive an electrodynamic machine for producing electrical power at a location where a reticulated power supply is unavailable. Some of the electrical power so produced can be utilised to operate the source providing the intermittent input energy.

It is against this background that the present invention was developed.

Disclosure of the Invention

According to a first aspect of the invention there is provided a drive mechanism comprising a drive gear rotatable in a driving direction about an axis during a driving event, a spring mechanism having a loaded condition and an unloaded condition, an input mechanism for loading the spring mechanism during a loading event, the spring mechanism when in the loaded condition being adapted to rotate the drive gear in the driving direction during the driving event, the driving event being of a duration exceeding that of the loading event.

Preferably, the duration of the driving event is significantly greater than the duration of the loading event such that the drive mechanism can deliver output energy for an extended duration as compared to the duration of energy input. Typically, the duration of the driving event is of at least an order of magnitude greater than the duration of the loading event.

Preferably, the axis is defined by an input shaft. In this way, the drive gear is supported for rotatiop about the input shaft.

Preferably, the spring mechanism comprises a spring having opposed first and second ends, the first end being fixed with respect to the drive gear at a location offset with respect to the axis of rotation of the drive gear.

^

Preferably, the spring comprises a helical tension spring adapted to undergo loading during extension thereof.

Preferably, the drive mechanism comprises a portion about which the spring can wrap during extension thereof.

Preferably, the drive gear is rotatably supported on the input mechanism.

Preferably, the input mechanism comprises epicyclic gearing having an input portion and an output portion. In one arrangement, the drive gear is rotatably supported on the output of the input mechanism. In this way, the drive gear is supported for rotation about the input shaft.

Typically, the input portion comprises the sun gear of the epicyclic gearing and, the output portion comprises the ring gear. With this arrangement, the portion of the drive mechanism about which the spring can wrap during extension thereof may comprise a loading plate fixed to the ring gear for rotation therewith. The loading plate may be provided with a circumferential ledge about which the extending spring can progressively locate during the loading event. The circumferential ledge is preferably configured as a channel in which the extending spring can be received. Typically, the channel is substantially arcuate in cross-section to provide a cradle for the extending spring.

Preferably the drive gear comprises an inner portion rotatably supported on the ring gear of the input mechanism (typically through a bearing) and an outer portion provided with gear teeth. The inner portion may be configured as a central annular disk and the outer portion may be configured as a rim.

The spring mechanism may comprise a further helical tension » spring. This increases the spring force available for driving the drive gear. Preferably, the two of the helical tension springs are disposed on opposed side of the central annular disk. With such an arrangement, there is preferably a further loading plate associated with further helical spring, with the two loading plates being disposed on opposed sides of the ring ge,ar.

According to a second aspect of the invention there is provided a drive mechanism comprising a drive gear rotatable about a shaft, a spring mechanism having a loaded condition and an unloaded condition, the spring mechanism when in the loaded condition being adapted to rotate the drive gear about the shaft, and an input mechanism for loading the spring mechanism upon rotation of the shaft relative to the drive gear.

Typically, the first direction of -rotation of the drive shaft constitutes a driving direction for the drive gear.

According to a third aspect of the invention there is provided apparatus incorporating a drive mechanism according to the first or second aspects of the invention. The apparatus may be capable of providing a sustained energy output over an extended duration with only intermittent energy input.

Preferably, the apparatus comprises a plurality of drive mechanisms according to the first or second aspects of the invention.

The plurality of drive mechanisms may be arranged in banks, each bank comprising one or more of the drive mechanisms mounted on an input shaft, the input shaft comprising part of the input mechanism for each drive mechanism on the input shaft.

Preferably, the sun gear of each drive mechanism is mounted for rotation with the input shaft on which the respective gear mechanism is mounted.

Each input shaft may receive input torque in any appropriate way. While, the input torque can be delivered to one end of each input shaft, it may be convenient that input torque be delivered to the input shaft at both ends thereof. The may be achieved by provision of a torque delivery mechanism, such as a hydraulic motor, at each end of each input shaft.

Preferably, each bank of drive mechanisms is in driving engagement with an output shaft. More particularly, the drive gears of drive mechanisms may be in meshing engagement with pinions mounted on the output shaft to provide direct driving engagement therewith.

The output shaft may comprise one of a plurality of output shafts each having pinions thereon, the arrangement being that at least one bank of drive mechanisms is in driving engagement with each output shaft.

A flywheel may be mounted on at least one output shaft.

Where there are a plurality of output shafts, they may be drivingly interconnected through a drive transfer mechanism such as, for example, a chain and sprocket assembly. T/AU2008/001026

- 5 -

Preferably each pinion is mounted on its respective output shaft to transmit drive thereto upon rotation of the pinion in one direction while not transmitting drive thereto upon rotation of the pinion in other direction.

This may be achieved by mounting the pinion on the output shaft through a clutch bearing which transmits rotation of the pinion to the shaft upon rotation of the pinion in said one direction while allowing the pinion to freewheel with respect to the output shaft when rotated in the other direction.

Preferably, the drive mechanisms in each bank are adapted to undergo rotation, sequentially.

A control means may be provided to restrain rotation of the drive gear of each drive mechanism until the immediately preceding drive mechanism has attained a certain condition, whereupon the drive gear is released to undergo rotation under the influence of its respective spring mechanism.

According to a fourth aspect of the invention there is provided apparatus comprising an input and an output, the input comprising an input shaft, a drive gear adapted to rotate about the input shaft, a spring mechanism having a loaded condition and an unloaded condition, the spring mechanism when in the loaded condition being adapted to rotate the drive gear about the input shaft, loading mechanism for loading the spring mechanism upon rotation of the input shaft relative to the drive gear, the spring mechanism when in the about the input shaft, the drive gear being drivingly connected to the output to impart rotational torque thereto when rotating in the driving direction.

Preferably, the drive gear rotates in the driving direction during a driving event, and the spring is loaded during a loading event, the driving event being of a duration exceeding that of the loading event.

Preferably, the output comprises an output shaft with which the drive gear is in driving engagement. Preferably, the input comprises an input shaft rotatable in one direction (being a loading direction) but constrained against rotation in the reverse direction. In this regard, the input shaft may be supported at one end by a clutch bearing. Preferably, the input shaft supported at both ends by respective clutch bearings.

Preferably a torque delivery mechanism is provided for selectively applying rotation torque to the input shaft to cause rotation thereof in the loading direction. The torque delivery mechanism may comprise a drive device, such as, for example, a hydraulic drive. There may be two drive devices, one drivingly connected to each end of the input shaft.

The input mechanism may comprise an epicyclic gearing having an input portion and an output portion. Typically, the input portion comprises the sun gear of the epicyclic gearing and the output portion comprises the ring gear.

Brief Description of the Drawings

The invention will be better understood by reference to the following description of several specific embodiments thereof, as shown in the accompanying drawings in which:

Figure 1 is a schematic perspective view (from one side) of apparatus according to a first embodiment;

Figure 2 is a schematic perspective view (from the other side) of the apparatus according to the first embodiment;

Figure 3 is a schematic perspective view (from one side) of apparatus, with an exterior covering removed to reveal banks of drive mechanisms forming part of the apparatus;

Figure 4 is a schematic perspective view (from the other side) of apparatus, with an exterior covering removed to reveal the banks of drive mechanisms; Figure 5 is a schematic perspective view (from one side) of apparatus, with the banks of drive mechanisms removed to reveal other componentry;

Figure 6 is a schematic perspective view (from the other side) of apparatus, with the banks of drive mechanisms removed to reveal other componentry;

Figure 7 is an exploded perspective view showing one bank of drive mechanisms and end plates between which the bank is supported;

Figure 8 is a perspective view of one of the drive mechanisms;

Figure 9 is a side view of figure 8;

Figure 10 is a perspective view of a one drive mechanism;

Figure 11 is an elevational view of Figure 10;

Figure 12 is a perspective view of a part of one drive mechanism, viewed from one side thereof;

Figure 13 is a view similar to figure 12 but viewed from another side thereof;

Figure 14 is a further elevational view of the drive mechanism;

Figure 15 is an exploded view of one of the drive mechanisms;

Figure 16 is a further exploded view, showing part of the drive mechanism;

Figure 17 is a perspective view of a drive gear forming part of the drive mechanism; Figure 18 is an elevational view of the drive gear;

Figure 19 is a side view of the drive gear;

Figure 20 is an elevational view of part of the drive mechanism, viewed from one side thereof, showing in particular one spring in the unloaded condition;

Figure 21 is a view similar to Figure 20 but from the other side thereof, showing in particular the other spring in the unloaded condition;

Figure 22 is an elevationai view of part of the drive mechanism, viewed from one side thereof, showing in particular one spring in the fully loaded condition;

Figure 23 is a view similar to Figure 22 but from the other side thereof, showing in particular the other spring in the fully loaded condition;

Figure 24 is an elevational view of a bank of drive mechanisms;

Figure 25 is a plan view of Figure 24;

Figure 26 is an underside view of Figure 24;

Figure 27 is a view of the bank of drive mechanisms of Figure 24 viewed from one side thereof;

Figure 28 is a view of the bank of drive mechanisms of Figure 24 viewed from one side thereof;

Figure 29 is a perspective view of one of the drive mechanisms showing in particular a cam thereon;

Figure 30 is an elevational view of the drive mechanism of Figure 29; Figure 31 is a plan view of the drive mechanism of Figure 29;

Figure 32 is a side view of the drive mechanism of Figure 29;

Figure 33 is a fragmentary view the drive mechanism of Figure 29 on an enlarged scale showing the cam;

Figure 34 is a perspective view of another of the drive mechanisms showing in particular a locking lug thereon;

Figure 35 is an elevational view of the drive mechanism of Figure 34, showing in particular the locking lug and also a cam on the drive mechanism;

Figure 36 is a plan view of the drive mechanism of Figure 34;

Figure 37 is a side view of the drive mechanism of Figure 34;

Figure 38 is a fragmentary view the drive mechanism of Figure 34 on an enlarged scale showing the cam;

Figure 39 is a fragmentary view the drive mechanism of Figure 34 on an enlarged scale showing the locking lug;

Figure 40 is a perspective view of still another of the drive mechanisms showing in particular a locking lug thereon;

Figure 41 is an elevational view of the drive mechanism of Figure 40;

Figure 42 is a plan view of the drive mechanism of Figure 40;

Figure 43 is a side view of the drive mechanism of Figure 40;

Figure 44 is a fragmentary view the drive mechanism of Figure 40 on an enlarged scale showing the locking lug; Figure 45 is a perspective view of a control means for controlling rotation of the drive mechanisms in each bank thereof in a timed sequence;

Figure 46 is an elevational view of the control means;

Figure 47 is a plan view of the control means;

Figure 48 is an underside view of the control means;

Figure 49 is a view of the control means from one side thereof;

Figure 50 is a view of the control means from the side thereof;

Figure 51 is a schematic perspective view (from one side) of apparatus according to a second emBodiment;

Figure 52 is a schematic perspective view (from the other side) of the apparatus according to the second embodiment;

Figure 53 is a side view of the apparatus;

Figure 54 is a plan view of the apparatus;

Figure 55 is an underside view of the apparatus;

Figure 56 is a further view of the apparatus;

Figure 57 is a section on line 56-56 of Figure 56; and

Figure 58 is a section on line 57-57 of Figure 56. Best Mode(s) for Carrying Out the Invention

The first embodiment, which is shown in Figures 1 to 50, is directed to a apparatus in the form of a torsional propulsion device functioning as an engine 10 for delivery of sustained mechanical power over an extended duration with only intermittent energy input.

The engine 10 may be used for any appropriate purpose. One possible application of the engine 10 may be to drive an electrodynamic machine for generating electrical energy, some of which may be used in operation of the engine.

The engine 10 according to the first embodiment comprises a plurality of input shafts 11, a first output shaft 13 and a second output shaft 15, each rotatably supported between two spaced end members configured as end plates 17, 18. A removable exterior covering 19 extends between the end plates 17, 18.

In this embodiment there are four input shafts 11, although not all input shafts are shown in the drawings.

Each input shaft 11 is supported for rotation in one direction while being constrained against rotation in the other direction. In the arrangement shown, each input shaft 11 is supported, at its ends on clutch bearings 12 which are adapted to permit rotation of the shaft in the one direction while preventing rotation in the other direction. The clutch bearings 12 are mounted on the end plates 17, 18.

Each input shaft 11 comprises a plurality of shaft sections 21 each having a first end 23 and a second end 25 configured for engagement with a coupling element (not shown), the purpose of which will be explained later.

Torque delivery mechanisms 26 are connected to the ends of the input shafts 11 to selectively deliver rotational torque tp the input shafts to cause them to rotate in said one direction. In the arrangement shown, each torque delivery mechanism 26 comprises a hydraulic drive 27 mounted on the adjacent end plate 17, 18. The hydraulic drives 27 are incorporated in a hydraulic system 28 which also incorporates a reservoir 29 for the hydraulic fluid and a hydraulic motors 30 for generating fluid flow to operate the hydraulic drives 27. The reservoir 29 is mounted on end plate 17.

Limit switches are provided to control operation of the hydraulics system; that is, to regulate the extent of rotation of each input shaft 11 under the control of the hydraulic system.

The first output shaft 13 has one end 31 , which is adjacent end plate 18, adapted to deliver shaft power. The other end of the first output shaft 13, which is adjacent end plate 17, is obscured in the drawings by the hydraulic fluid reservoir 29.

The second output shaft 15 has one end which extends beyond end plate 17 and which supports a flywheel 33. The flywheel 33 is disposed adjacent the hydraulic fluid reservoir 29. The flywheel is configured to generate air flow upon rotation thereof. With this arrangement, air flow created by the rotating flywheel 33 can pass over the hydraulic system 28 (including the fluid reservoir 29) to assist cooling of hydraulic fluid contained therein.

A cooling system comprising a fan 30 is provided for cooling hydraulic fluid contained in the hydraulic system 28.

The output shafts 13, 15 are drivingly interconnected by a chain and sprocket assembly 16 located on the outer side of end plate 18.

Shaft power delivered by the engine 10 can be extracted from either or both of the output shafts 13, 15. In this embodiment, the shaft power is extracted from the flywheel 33.

Each input shaft 11 supports a plurality of drive mechanisms 40 between the end plates 17, 18. In the arrangement shown, each input shaft 11 supports a bank of four drive mechanisms 41 , _.42, 43 and 44. There are four banks of drive mechanisms 40 in this embodiment, one corresponding to each of the four input shafts 11.

The drive mechanisms 41 , 42, 43 and 44 in each bank are adapted to drivingiy rotate in timed sequence, as will be explained later.

Each drive mechanism 40 is drivingiy connected to either the first output shaft 13 or the second output shaft 15. The first output shaft 13 has four pinions 51 mounted for rotation therewith, and the second output shaft 15 also has four pinions 53 mounted for rotation therewith. Each pinion 51 , 53 is mounted on its respective output shaft 13,15 through a clutch bearing (not shown) which transmits rotation of the pinion to the output shaft upon rotation of the pinion in one direction while ^allowing the pinion to freewheel with respect to the output shaft when rotated in the other direction. Each drive mechanism 40 has a drive gear 45 incorporating gear teeth 47 for meshing engagement with one of the pinions 51 , 53 to provide the driving connection between the drive mechanism 40 and the output shaft 13, 15.

In the arrangement shown, there are four banks 60 of drive mechanisms 40, with two banks 61 , 62 drivingiy connected to output shaft 13 and the other two banks 63, 64 drivingiy connected to output shaft 15.

Each drive mechanism 40 comprises the respective drive gear 45, an input mechanism 71 , and a spring mechanism 73 operably connected to the drive gear 45. The spring mechanism 73 is adapted to be loaded by the input mechanism 71 during the loading event. The loaded spring mechanism 73 is adapted to rotate the drive gear in a driving direction during a driving event, the driving event being of a duration exceeding that of the loading event.

The duration of the driving event is significantly greater than the duration of the loading event such that the drive mechanism 40 can deliver output energy for an extended duration as compared to the duration of energy input. Typically, the duration of the driving event is of at least an order of magnitude greater than the duration of the loading event.

The spring mechanism 73 comprises two helical tension springs 75 adapted to undergo loading during extension thereof. Each spring 75 has a first end 76 and a second end 77.

The drive gear 45 comprises an inner portion 81 and an outer portion 83 provided with the gear teeth 47. The inner portion 81 is configured as a annular disk 85 having a central opening 87. The outer portion 83 is configured as a rim 89 with the gear teeth 47 provided on the outer circumferential face thereof.

The input mechanism 71 comprises epicyclic (or planetary) gearing 91 having an inner sun gear _k93, planetary gears 95 and an outer ring gear 97. , The sun gear 93 is mounted on the respective input shaft 11 for rotation therewith. More particularly, the sun gear 93 is mounted on one of the shaft sections 21. The planetary gears are each mounted on a carrier 99 configured as a carrier plate.

The ring gear 97 carries two loading plates 101 , one on each side of the ring gear. Each loading plate 101 has an inner portion 103 adapted to be fastened to the ring gear 97 for rotation therewith. Each loading plate 101 also has a circumferential guide surface 105 which comprises an annular ledge and about which a respective one of the springs 75 can progressively locate during the loading event. The circumferential guide surface 105 is configured as a channel 107 in which the extending spring can be received. The channel 107 is substantially arcuate in cross-section to provide a cradle for the extending spring 75.

The drive gear 45 is rotatably supported on the ring gear 97 by a bearing 111 which in the arrangement shown is a roller bearing.

The bearing 111 has a radially inner portion 113 fixed to the ring gear 97 and a radially outer portion 115 fixed to the annular disk 85 of the drive gear 45, the outer portion 115 being accommodated in the central opening 87 of the annular disk 85.

Each spring 75 has its first end 76 anchored to a mounting pin 121 on the annular disk 85 of the drive gear 45 and its second end 77 anchored to a mounting pin 123 on the respective loading plate 101. With this arrangement, each spring 75 is caused to undergo loading through progressive extension the loading plate 101 to which it is connected rotates with the ring gear 97 upon rotation of the respective input shaft 11. At this stage, the drive gear 45 to which the extending springs 75 are connected is restrained against rotation under the influence of the progressively increasing spring force imposed on it by the extending spring by virtue of the meshing engagement with one or more other drive mechanisms, the output shaft 13 or the second output shaft 15, as the case may be. As each spring 75 expands, it wraps around the guide surface 105 of its respective loading plate 101 , as best seen in Figure 18. This is advantageous, as if allows the springs to extend but in a compact manner. The guide surface 105, and the associated channel 107, guide the spring 75 as it extends during the loading event.

The springs 75 are shown in the unloaded condition in Figures 17, 24 and 25, and are shown in the fully loaded condition in Figures 14, 15, 26 and 27. The loaded condition of each spring 75 corresponds to any extension of the spring, between the fully loaded condition and a condition immediately prior to the unloaded condition, during which the spring is in a state to exert an effective spring force.

The loading event is rapid, typically occurring within the duration of a few seconds. The rapid loading is achieved in this embodiment through use of the epicyclic gearing 91. At the completion of the loading event, the springs 75 are fully extended. The spring force imposed by the extended springs 75 acts in the drive gear 45 to cause it to rotate. The rotating drive gear 45 transmits rotational torque to any rotating element with which it is in meshing engagement (being one or more other drive mechanisms, the first output shaft 13 or the second output shaft 15, as the case may be). In this way, rotational torque of the drive mechanism is ultimately transmitted to the output shaft 13, as previously explained.

Torque is delivered to the various input shafts 11 in timed sequence. In this embodiment, where there are four input shafts 11 ,. torque is delivered to the input shafts in a cyclical fashion at intervals of %, Vz, % and 1. In this way, the banks of drive mechanisms 40 are loaded in a timed sequence such that each is about 90° out of phase with another during operation of the engine.

Torque may be delivered to the input shafts periodically as necessary according to the load demands on the engine. In circumstances where there is no load demand on the engine, the springs 73 can remain in the loaded condition in readipess to deliver drive to the drive gears 45 when necessary in order to meet any subsequent load demand on the engine.

As mentioned earlier, the drive mechanisms 41 , 42, 43 and 44 in each bank 60 of drive mechanisms are adapted to drivingly rotate, and thereby apply rotational torque to the respective output shaft 13, 15, in timed sequence. In this regard, a control means 130 is provided for controlling the timing of rotation of the drive gears 45 in each bank 60.

In this embodiment, rotation of the drive gear 45 of each drive mechanism 40 commences once the drive gear of the preceding drive mechanism has undergone about % of its drive rotation cycle. Rotation commences with the first drive mechanism 41 , and then drive mechanisms 42, 43 and 44 follow sequentially. Because the pinions 51, 53 can freewheel on the output shafts 13,

15 as previously explained, it is possible for the drive gears 45 of some drive mechanisms 40 to rotate while others do not rotate.

The control means 130 associated with each bank 60 comprises a releasable locking mechanisms 131 associated with each of the drive mechanisms which follow the first drive mechanism. With this arrangement, there is releasable locking mechanism 131 a associated with the second drive mechanism 42, releasable locking mechanism 131 b associated vyith the third drive mechanism 43, and releasable locking mechanism 131c associated with the fourth drive mechanism 44.

Each releasable locking mechanism 131 comprises a pawl 133 engageable with

5 a restraining portion 135 on the respective drive gear 45. The restraining portion

135 comprises a lug 137, the. arrangement being that engagement of the pawl

133 with the lug 137 locks the drive gear 45 against rotation. Each lug 137 comprises a locking face 138 with which the pawl can engage to lock the drive gear 45 against rotation and a ramp face 139 over which the pawl can ride to

10 engage the locking face 138. The pawls 133 are mounted on a common shaft

141 for limited pivotal movement between engaging and release conditions with respect to the lugs 137. The common shaft 141 is supported between the end

< plates 17, 18 and is fixed against rotation. <

A spring 143 biases each pawl 133 into its engaging condition. The spring 143 15 acts between the pawl 133 and the common shaft 141.

The control means 130 associated with each bank ^βO also comprises a cam . mechanism 150 associated with each of the drive mechanisms 41, 42_S 43 and 44.

Each cam mechanism 150 comprises a cam 151 provided on the periphery of -20 the respective drive gear 45 and a cam follower 153 for engagement with the cam 151 upon rotation of the drive gear 45.

The cam follower 153 associated with the drive gear 45 of the first drive mechanism 41 is supported on a finger 155. The finger 155 is pivotally mounted on the common shaft 141 for limited pivotal movement between two end 25 positions, one corresponding to the fail of the cam follower 153 and the other corresponding to the rise of the cam follower 153. A spring 157 biases the finger 155 to the end position corresponding to the fall of the cam follower 153. The cam followers 153 associated with the other drive mechanisms 42, 43 and 44 are supported on the respective pawls 133. The pivotal mounting of the pawls 133 on the common shaft 141 accommodates not only movement of the pawls between the engaging and release conditions with respect to the lugs 137, but also rise and fall of the cam followers 153 with respect to the cams 151. The springs 143, in biasing the pawls 133 into the engaging condition with respect to the lugs 137, also biases the pawls into positions corresponding to the fall of the cam followers 153.

In the arrangement shown, the cam followers 153 are configured as rollers.

The control means 130 associated with each bank 60 also comprises an actuating mechanism 160 operably interconnecting the releasable locking mechanisms 131 and the cam mechanisms 150. The actuating mechanism 160 comprises a series of actuating sleeves 161 rotatably supported on the common shaft 141. One sleeve 161a is associated with the finger 155 mounted on the shaft 141 , and the other sleeves 161 b, 161c and 161d are associated with the pawls 133. Each sleeve 161 has an aperture 165 through which the finger 155 or one of the pawls 133 extends (as the case may be). The finger 155 and the pawls 133 are close fits in their respective apertures 165, such that pivotal movement of the finger 155 cause rotation of its sleeve 161a about the shaft 141 and pivotal movement of each pawl 133 causes rotation of its respective sleeve 161 b, 161 c, 161 d about the shaft 141.

The actuating sleeves 161 are connected one to another through a lost-motion coupling 177. Adjacent ends of the sleeves 161 are configured to provide a projection 171 and a recess 173, the arrangement being that the projection 171 on one sleeve 161 is received in the recess 173 of the adjacent sleeve, and vice versa. In each case, the recess 173 is larger than the projection 171 so that there is some lost-motion in the coupling therebetween upon rotation of one sleeve with respect to the sleeve adjacent thereto. The effect of this is that one sleeve 161 can rotate about the shaft 141 to a limited extent before that rotation is transmitted to the adjacent sleeve 161. This thus provides the lost-motion coupling 177. In the arrangement shown, the ends of the sleeves 161 are configured to provide the projection 171 and recess 173 by removal of a segment of each sleeve at the respective end thereof. The segment removed (which leads to the creation of the recess 173) is radially larger than the segment remaining (which defines the projection 171).

Operation of the control means 130 will now be described in relation to operation of one of the banks 60. Following the loading event for the drive mechanisms 40 in the bank, the drive gear 45 of the first drive mechanism 41 commences to rotate under the influence of its spring mechanism 73. At this stage, the other three drive gears 42, 43 and 44 are restrained against rotation by engagement of the pawls 133 with the lugs 137.

As the drive gear 45 rotates, the cam 151 approaches the respective cam follower 153. Once the drive gear 45 has completed a prescribed extent of its rotation (for example, VA of the rotation), the cam 151 contacts the cam follower 153. This causes the cam follower 153 to rise, so causing the finger 155 to pivot on the shaft 141. The pivotal movement of the finger 155 causes rotation of the first actuating sleeve 161a about the shaft 141 , as previously explained. The coupling 177 then causes the adjacent second sleeve 161b to rotate, so causing the pawl 133 engaging the lug 137 on the drive gear of the second drive mechanism 42 to release that lug. This allows rotation of the drive gear 45 of the second drive mechanism 42 to commence rotation also. Now the drive gears 45 for both the first and second drive mechanisms 41 , 42 are undergoing rotation and transferring torque to the particular output shaft 13, 15 with which they are in driving engagement. Because of the lost-motion coupling 177 between the second sleeve 161b and the third sleeve 161c adjacent thereto, rotation of the second sleeve 161b in response to rotation of the first sleeve 161a is not transmitted to the third sleeve 161c.

Once the drive gear 45 of the second drive mechanism 42 has completed a prescribed extent of its rotation (for example, ^ΛA of the rotation), the cam 151 ' thereon contacts the cam follower 153 associated with the second sleeve 161 b. This causes the cam follower 153 to rise, so causing the respective pawl 133 to pivot on the shaft 141. The pivotal movement of the pawl 133 causes rotation of the second actuating sleeve 161b about the shaft 141, as previously explained. The coupling 177 then causes the adjacent third sleeve 161c to rotate, so causing the pawl 133 engaging the lug 137 on the drive gear of the third drive mechanism 43 to release that lug. This allows rotation of the drive gear 45 of the third drive mechanism 43 to commence rotation also. Now the drive gears 45 for the first, second and third drive mechanisrns 41 , 42, 43 are undergoing rotation and transferring torque to the particular output shaft 13, 15 with which they are in driving engagement. Because of the lost-motion coupling 177 between the third sleeve 161c and the fourth sleeve 161d adjacent thereto, rotation of the third sleeve 161c in response to rotation of the second sleeve 161d is not transmitted to the fourth sleeve 161d.

Once the drive gear 45 of the third drive mechanism 43 has completed a prescribed extent of its rotation (for example, ^ΛA of the rotation), the cam 151 thereon contacts the cam follower 153 associated with the third sleeve 161c.

This causes the cam follower 153 to rise, so causing the respective pawl 133 to pivot on the shaft 141. The pivotal movement of the pawl 133 causes rotation of the third actuating sleeve 161c about the shaft 141 , as previously explained. The coupling 177 then causes the adjacent fourth sleeve 161d to rotate, so causing the pawl 133 engaging the lug 137 on the drive gear of the fourth drive mechanism 44 to release that lug. This allows rotation of the drive gear 45 of the fourth drive mechanism 44 to commence rotation also. Now the drive gears 45 for the first, second, third and fourth drive mechanisms 41 , 42, 43, 44 are undergoing rotation and transferring torque to the particular output shaft 13, 15 with which they are in driving engagement.

The drive gears 45 complete their rotations sequentially. Each drive gear 45 completes its rotation at a predetermined angular position. In this way, the pawls 133 engage their respective lugs 137 in readiness for the next loading event, and the cycle repeats. The various banks 60 are loaded sequentially, with overlapping of the operation of the banks, so that toque is delivered to the output shafts 13, 15 in a somewhat uniform matter when there is a load demand on the engine.10.

The engine may also continue to operate for some time after cessation of operation of the torque delivery mechanisms 26, owing to the presence of the flywheel 33.

The engine is of modular construction, allowing any number of drive mechanisms 40 in each bank. This is facilitated by the sectional construction of each input shaft 11 involving shaft sections 21. Indeed, each drive mechanism 40 is of unitary construction, as best seen in Figures 12 and 13, involving a shaft section 21 connected to the sun gear 93 of the epicyclic gearing 91 associated with the particular drive mechanism. ln,this way, a number of drive mechanisms can be < installed in series, with coupling elements (not shown) interconnecting the series of shaft sections 21.

Referring to Figures 51 to 55, there is shown apparatus in the form of a torsional propulsion device functioning as an engine 200 for delivery of sustained mechanical power over an extended duration with only intermittent energy input. The engine 200 is of a simpler and more compact construction than the engine 10 according to the first embodiment. The engine 200 may be used for any appropriate purpose. One possible application of the engine 200 may be to power a lightweight motor vehicle such as a motorcycle or auto-rickshaw.

The engine 200 according to the second embodiment comprises input shaft 201 and an output shaft 203, each rotatably supported within a frame structure 205.

The input shaft 201 is supported for rotation in one direction while being constrained against rotation in the other direction.

The input shaft 201 supports a plurality of drive mechanisms 210. In the arrangement shown, the input shaft. 201 supports a bank of two drive mechanisms 211 , 212. The drive mechanisms 211 , 212 are essentially of the same construction, and operate in a similar way, as the drive mechanisms 40 in the first embodiment.

The drive mechanisms 211, 212 in the bank are adapted to drivingly rotate in timed sequence. While not shown in the drawings, the engine 200 incorporates a further input shaft supporting a further bank of two drive mechanisms. With this arrangement, the engine 200 has four drive mechanisms adapted to drivingly rotate in timed sequence, as was the case in the first embodiment.

A torque delivery mechanism 215 is provided to selectively deliver rotational torque to the input shaft 201 to cause it to rotate in said one direction. In the arrangement shown, the two drive mechanisms 211 , 212 are in spaced apart relation on the input shaft 201 , and the torque delivery mechanism 215 is operably coupled to the section of the input shaft 201 between the two d/ive mechanisms 211, 212.

The torque delivery mechanism 215 comprises a rack and pinion mechanism 217. The rack and pinion mechanism 217 comprises a pinion 219 mounted on the input shaft 201 and a rack 221 in meshing engagement with the pinion. The pinion 219 is mounted on the input shaft 201 through a clutch bearing (not shown) which transmits rotation of the pinion to the input shaft upon rotation of the pinion in one direction while allowing the pinion to freewheel with respect to the input shaft when rotated in the other direction.

A power device 223 is provided for selectively actuating the rack. In the arrangement illustrated, the power device 223 comprises a hydraulic ram 225.

Each drive mechanism 211 , 212 is drivingly connected to the output shaft 203. The output shaft 203 has two pinions 231 , 232 mounted for rotation therewith. Each pinion 231 , 232 is mounted on the output shaft 203 through a respective clutch bearing 233 which transmits rotation of the pinion to the output shaft upon rotation of the pinion in one direction while allowing the pinion to freewheel with respect to the output shaft when - rotated in the other direction. Each drive mechanism 211 , 212 has a drive gear 235 incorporating gear teeth 237 for meshing engagement with the respective pinion 231 , 232 to provide the driving connection between the drive mechanism and the output shaft 203..

Shaft power delivered by the engine 200 can be extracted from the output shaft 203 via an output gear 237..

A control means (not shown) is provided for controlling operation of the engine to cause the four drive mechanisms (only two of which appear in the drawings, as previously mentioned) to drivingly rotate in timed sequence to deliver shaft power on a continuous basis while the engine is in operation. The engine operation involves intermittent actuation of the torque delivery mechanism 215, as was the case with the first embodiment.

From the forgoing, it is evident that the present embodiments each provides an engine capable of sustained delivery of mechanical, energy with intermittent energy input. The engine operates to deliver mechanical energy for an extended duration in comparison to the duration of energy input into the engine.

Improvements and modifications may be incorporated without departing from the scope of the invention.

Throughout the specification, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

Claims

_The Claims Defining the Invention are as Follows:

1. A drive mechanism comprising a drive gear rotatable in a driving direction about an axis during a driving event, a spring mechanism having a loaded condition and an unloaded condition, an input mechanism for loading the spring mechanism during a loading event, the spring mechanism when in the loaded condition being adapted to rotate the drive gear in the driving direction during the driving event, the driving event being of a duration exceeding that of the loading event.

2. A drive mechanism according to claim 1 wherein the duration of the driving event is significantly greater than the duration of the loading event such that the drive mechanism can deliver output energy for an extended duration as compared to the duration of energy input.

3. A drive mechanism according to claim 2 wherein the duration of the driving event is of at least an order of magnitude greater than the duration of the loading event.

4. A drive mechanism according to claim 1 , 2 or 3 wherein the axis is defined by an input shaft and the drive gear is supported for rotation about the input shaft.

5. A drive mechanism according to any one of the preceding claims wherein the spring mechanism comprises a spring having opposed first and second ends, the first end being fixed with respect to the drive gear at a location offset with respect to the axis of rotation of the drive gear.

6. A drive mechanism according to claim 5 wherein the spring comprises a helical tension spring adapted to undergo loading during extension thereof.

7. A drive mechanism according to claim 5 or 6 further comprising a portion about which the spring can wrap during extension thereof.

8. A drive mechanism according to any one of the preceding claims wherein the drive gear is rotatably supported on the input mechanism. __

9. A drive mechanism according to any one of the preceding claims wherein the input mechanism comprises epicyclic gearing having an input portion and an output portion. I

10.A drive mechanism according to claim 9 wherein the drive gear is rotatably supported on the output of the input mechanism.

11. A drive mechanism according to. claim 9 or 10 wherein the input portion comprises the sun gear of the epicyclic gearing and the output portion comprises the ring gear of the epicyciic gearing.

12.A drive mechanism according to claim 11 wherein the portion of the drive mechanism about which the spring can wrap during extension thereof comprises a loading plate fixed to the ring gear for rotation therewith.

13.A drive mechanism according to claim 12 wherein the loading plate is provided with a circumferential ledge about which the extending spring can progressively locate during the loading event.

14.A drive mechanism according to claim 13 wherein the circumferential ledge is configured as a channel in which the extending spring can be received.

15. A drive mechanism according to claim 14 wherein the channel is substantially arcuate in cross-section to provide a cradle for the extending spring.

16.A drive mechanism according to claim 11 wherein the drive gear comprises an inner portion rotatably supported on the ring , gear of the input mechanism and an outer portion provided with gear teeth.

17.A drive mechanism according to claim 16 wherein the inner portion is configured as a central annular disk and the outer portion may be configured as a rim.

18.A drive mechanism according to any one of claims 5 to 17 wherein the spring mechanism comprises a further helical tension spring. _

19. A drive mechanism according to claim 18 wherein the two of the helical tension springs are disposed on opposed side of the central annular disk.

20.A drive mechanism according to claim 19 wherein there is provided a , further loading plate associated with further helical spring, with the two loading plates being disposed on opposed sides of the ring gear.

21.A drive mechanism comprising a drive gear rotatable about a shaft, a spring mechanism having a loaded condition and an unloaded condition, the spring mechanism when in the loaded condition being adapted to rotate the drive gear about the shaft, and an input mechanism for loading the spring mechanism upon rotation of the shaft relative to the drive gear.

22.A drive mechanism according to claim 21 wherein the first direction of rotation of the drive shaft constitutes a driving direction for the drive gear.

23.Apparatus incorporating a drive mechanism according to any one of the preceding claims.

24.Apparatus comprises a plurality of drive mechanisms according to anyone of claims 1 to 22.

25.Apparatus according to claim 24 wherein the plurality of drive mechanisms are arranged in banks, each bank comprising one or more of the drive mechanisms mounted on an input shaft, the input shaft comprising part of the input mechanism for each drive mechanism on the input shaft.

26.Apparatus according to claim 25 wherein the sun gear of each drive mechanism is mounted for rotation with the input shaft on which the respective gear mechanism is mounted.

27.Apparatus according to claim 26 wherein each bank of drive mechanisms is in driving engagement with an output shaft. _

28.Apparatus according to claim 27 wherein the drive gears of drive mechanisms are in _. meshing engagement with pinions mounted on the output shaft to provide direct driving engagement therewith.

29.Apparatus according to claim 28 wherein the output shaft comprises one of a plurality of output shafts each having pinions thereon, the arrangement being that at least one bank of drive mechanisms is in driving engagement with each output shaft.

3O.Apparatus according to claim 29 wherein a flywheel is mounted on at least one output shaft.

31. Apparatus according to claim 29 or 30 wherein the output shafts are drivingly interconnected through a drive transfer mechanism.

32.Apparatus according to claim 29 to 31 wherein the' each pinion is mounted on its respective output shaft to transmit drive thereto upon rotation of the pinion in one direction while not transmitting drive thereto upon rotation of the pinion in other direction.

33.Apparatus according to any one of claims 25 to 32 wherein the drive mechanisms in each bank are adapted to undergo rotation sequentially.

34.Apparatus according to claim 33 further comprising a control means for selectively restraining rotation of the drive gear of each drive mechanism relative to another.

35.Apparatus according to claim 34 wherein the control means is adapted to restrain rotation of the drive gear of each drive mechanism until the immediately preceding drive mechanism has attained a certain condition, whereupon the drive gear is released to undergo rotation under the influence of its respective spring mechanism.

36.Apparatus comprising an input and an output, the input comprising an input shaft, a drfve gear adapted to rotate about the input shaft, a spring mechanism having a loaded condition and an unloaded condition, the spring mechanism _

when in the loaded condition being adapted to rotate the drive gear about the input shaft, loading mechanism for loading the spring mechanism upon rotation of the input shaft relative to the drive gear, the spring mechanism when in the about the input shaft, the drive gear being drivingly connected to the output to impart rotational torque thereto when rotating in the driving direction.

37.Apparatus according to claim 36 wherein the drive gear rotates in the driving direction during a driving event, and the spring is loaded during a loading event, the driving event being of a duration exceeding that of the loading event.

38.Apparatus according to claim 36 or 37 wherein the output comprises an output shaft with which the drive gear is in driving engagement.

39.Apparatus according to claim 36 or 37 wherein the input comprises an input shaft rotatable in one direction (being a loading direction) but constrained ^y against rotation in the reverse direction.

4O.Apparatus according to claim 36 to 39 further comprising a torque delivery mechanism for selectively applying rotation torque to the input shaft to cause rotation thereof in the loading direction.

41.Apparatus according to claim 36 to 39 wherein the input mechanism comprises an epicyclic gearing having an input portion and an output portion.

42.Apparatus according to claim 41 wherein the input portion comprises the sun gear of the epicyclic gearing and the output portion comprises the ring gear of the epicyclic gearing.

43.A drive mechanism substantially as herein described with reference to the accompanying drawings.

44.Apparatus substantially as herein described with reference to the accompanying drawings.