This invention relates to an assisted pendulum device and particularly but not exclusively an assisted pendulum device for use in transporting water uphill.

A significant proportion of the total energy consumption in the world today may be attributed to the transportation of materials. Some transportation requirements are complex and span vast geographical areas, thereby leaving limited transportation options. For example, transportation of goods overseas must generally be effected by shipping or air freighting, whilst transportation of fluids is generally effected by large underground pipe networks. However, some transportation requirements comprise continuous or repeated transportation of the same materials over a moderately small distance and therefore other transportation methods may be suitable.

The applicant has recognised that current transportation methods generally consume more energy than required to do the transportation task.

In accordance with the present invention, as seen from a first aspect, there is provided an assisted pendulum device comprising a pendulum bob coupled to a pendulum arm such that the bob is arranged to swing under the action of gravity from a first position to a second position, the device further comprising assistance means for driving the pendulum bob from the second position to a third position at a greater height than the second position.

The first position is preferably defined by the position at which the bob, coupled to the arm, is released. It will be appreciated that if there were no energy losses due to friction and/or air-resistance then the second position would be at the same height as the first position. In reality, the second position is likely to be marginally lower than the first position. The third position is preferably at a greater height than the first position. In this way the final height of the bob of the assisted pendulum is greater than the initial height.

The arm may be rotatably coupled to a body about a first rotation axis. The first rotation axis is preferably disposed intermediate first and second ends of the arm such that the first rotation axis divides the arm in to an upper portion and a lower portion.

The pendulum bob may comprise materials that a user wishes to transport. Accordingly, one advantage of the present invention is that it enables the transportation of materials from the first position to the second position without the requirement for any external power, thereby minimising the total power required in order to transport materials from the first position to the third position. The pendulum arm may releasably engage the pendulum bob. Alternatively, the bob may be fixedly coupled to the arm.

The bob may be coupled to a lower end of the lower portion of the arm. Alternatively, the pendulum bob may be arranged to move relative to the pendulum arm in a direction substantially parallel to a longitudinal direction of the arm. The pendulum bob may be arranged to move towards a distal end the arm as the pendulum bob moves from the first position to the third position. In this way, the distance between the first axis and the pendulum bob increases as the pendulum bob moves from the first position to the third position. The distal end of the arm may comprise a U-shaped portion arranged to engage the pendulum bob and prevent further movement away from the first axis.

The body may be rotatably mounted about a second rotation axis. Preferably the second rotation axis is not collinear with the first rotation axis. The first rotation axis is preferably rotatable about the second rotation axis.

Preferably the device comprises trigger means arranged for activating the assistance means to drive the pendulum bob from the second position to the third position in accordance with a stimulus.

The trigger means may comprise position measurement means for measuring the position of the bob. Said position measurement means may comprise a sensor, which may be a light sensor adapted to detect a reduction in light as the pendulum arm and/or pendulum bob passes thereby. Alternatively, or in addition thereto, the position measurement means may comprise copper brushes arranged to contact the arm at a given position thereof, the copper brushes being configured to pass a current through the arm to complete an electric circuit. The trigger means may be arranged to activate the assistance means when the bob reaches a certain position. Said position is preferably closer to the second position than the first position, and most preferably substantially equal to the second position.

Alternatively, or in addition thereto, the trigger means may comprise velocity measurement means for measuring the velocity of the pendulum bob. The trigger means may be arranged to activate the assistance means when the velocity of the pendulum bob is below a lower threshold value.

The device may comprise a processor adapted to predict a future position and/or future velocity of the pendulum bob based on the current position and and/or the current speed.

The trigger means may be arranged to activate the assistance means at a future time at which the processor has predicted the position and/or the velocity of the pendulum bob will be equal to a pre-determined position and/or velocity.

The pendulum bob may comprise a cavity for holding a fluid such as water. Preferably the cavity comprises sealing means, which may be arranged to allow fluid to enter the cavity at the first position of the pendulum bob. Preferably the sealing means is arranged to seal said fluid within the cavity as the pendulum bob passes from the first position to the third position. The sealing means may be arranged to allow fluid to exit the cavity at the third position of the pendulum bob. The opening and closing of the sealing means may be controlled by the processor. Alternatively, or in addition thereto, the pendulum bob may be detachably coupled to the pendulum arm. The bob is preferably arranged to engage with the arm at the first position and preferably arranged to disengage with the arm at the third position. The engagement and disengagement of the pendulum bob may be controlled by the processor. Once disengaged, the bob may pass onto a track, which may be an inclined track such that once the bob is decoupled from the arm the bob travels downwardly along the inclined track from an upper end to a lower end thereof. Preferably the height of the upper end of the inclined track is substantially equal to the third height. The height of the lower end of the inclined track may be substantially equal to the first height.

The pendulum device may be arranged to assist the pendulum bob in a first angular direction and in a second angular direction. In this embodiment, the third position of the first swing may define the first position of a second swing of the pendulum, the second swing being in an opposite angular direction to the first swing. In this embodiment, the height of the pendulum bob at the third position of the second swing will be greater than the height of the pendulum bob at the third position of the third swing. Alternatively, the pendulum device may be arranged to assist the pendulum bob in one angular direction only, the second angular direction comprising no assistance such that the height of the pendulum bob at the end of the swing is substantially equal to the height of the pendulum bob at the beginning of the swing.

The assistance means is preferably adapted to drive rotation of the pendulum arm about the first axis in said angular direction of travel of the pendulum bob in its passage from the first position to the second position.

The assistance means may comprise a hammer arranged to strike the arm and/or the bob. The hammer is preferably arranged to strike the arm and/or bob at least before the bob reaches the second position. The hammer may be arranged to remain in contact with the arm and/or bob for a set distance or a set time period after striking the arm and/or bob.

The hammer may apply a force to the arm and/or bob for at least part of the time or distance during which the hammer is engaged therewith. Preferably the hammer is arranged to apply a force to the arm and/or bob for all of the time or distance during which the formation is engaged therewith.

The force exerted by the hammer may comprise a component in the upward direction. Preferably the hammer is arranged to exert a force in a direction substantially parallel to a direction of motion of the bob at the time at which the force is exerted. More preferably, the hammer is arranged to exert a force in an angular direction substantially equal to the angular direction of motion of the pendulum bob in its passage from the first position to the second position. The hammer may be configured to receive energy from an external source. The hammer may be actuated by an electromagnet, the electromagnet preferably being arranged to receive energy from an external power source such as a battery. Preferably the hammer is formed of a magnetic material and hence urged towards the arm and/or bob upon energisation of the electromagnet. In this embodiment, the trigger means may comprise an electronic switch arranged to selectively connect the electromagnet with the power source.

Alternatively or in addition thereto, the assistance means may comprise means for rotating the body portion about the second rotation axis.

In the embodiment in which the assistance means comprises means for rotation the body portion about the second rotation axis, the assistance means may comprise means for substantially preventing rotation of the pendulum arm about the first axis at least in an angular direction opposite to the angular direction of travel of the pendulum bob in its passage from the first position to the second position. Preferably the assistance means comprises means for substantially preventing any rotation of the pendulum arm about the first axis.

Said means for rotating the body portion about the second rotation axis may comprise a motor. Alternatively, or in addition thereto, said means for rotating the body portion about the second rotation axis may comprise a weighted member fixedly coupled to the body. The weighted member may be integral with the formation or may be separate therefrom. The weighted member is preferably arranged to move from a higher position when the pendulum bob is at the first position to a lower position when the pendulum bob is at the second position, the movement of the weighted member preferably being effected by rotation of the body about the second axis. The weighted member may be reset to the higher position after the pendulum bob has arrived at the third position, this preferably being effected by external resetting means configured to rotate the body of the pendulum. The mass of the weighted member may be selected in accordance with the mass of the bob and the required height difference between the second and third positions of the bob:

h(third position) - h(SeCOnd position) = Ahweighed member ^■ (mweighted member / rribob)

Where Ahweighted member is the height difference between the initial and final positions of the weighted member; m _W eighted member is the mass of the weighted member; and, rribob is the mass of the bob. It will be appreciated that the above calculation is based on the assumption that the mass of the arm is negligible and there are no frictional losses of energy. The device may comprise releasable locking means, the locking means being arranged to substantially prevent rotation of the body about the second rotation axis when engaged therewith and permit rotation of the body about the second rotation axis when disengaged therewith. In this embodiment, the trigger means may be arranged to selectively disengage the locking means to enable the gravitational force acting on the weighted member to drive rotation of the body about the second rotation axis.

The assistance means may comprise a formation arranged to releasably engage the arm and/or the bob.

The formation may be fixedly coupled to the body such that the rotation of the body about the second axis drives the formation.

The formation is preferably arranged to engage the upper portion of the arm. The formation is preferably arranged to engage the arm and/or the bob at least before the pendulum bob reaches the second position. Preferably the formation is arranged to disengage the arm and/or bob at least before the pendulum bob reaches the third position. Preferably the formation is arranged to selectively physically abut the arm and/or the bob, the formation preferably being configured to exert a force on the arm and/or bob when in physical contact therewith.

The formation may be arranged to strike the arm and/or the bob i.e. the formation may have a non-zero velocity at the moment at which the formation initially contacts the arm. The formation is preferably arranged to strike the arm and/or bob at least before the pendulum bob reaches the second position. The formation may be arranged to remain in contact with the arm and/or bob for a set distance or a set time period after striking the arm and/or bob.

Alternatively the formation may be arranged to magnetically engage the arm. Said magnetic engagement may comprise an attractive magnetic force provided on a side of the arm and/or bob proximal to the third position. Alternatively, said magnetic engagement may comprise a repulsive magnetic force provided on a side of the arm and/or bob distal from the third position. Preferably said magnetic engagement is provided by an electromagnet, thereby enabling rapid engagement and disengagement of the formation.

The formation may apply a force to the arm and/or bob for at least part of the time or distance during which the formation is engaged therewith. Preferably the formation is arranged to apply a force to the arm and/or bob for all of the time or distance during which the formation is engaged therewith.

The force exerted by the formation may comprise a component in the upward direction. Preferably the formation is arranged to exert a force in a direction substantially parallel to a direction of motion of the bob at the time at which the force is exerted. More preferably, the formation is arranged to exert a force in an angular direction substantially equal to the angular direction of motion of the pendulum bob in its passage from the first position to the second position.

The formation may be reconfigurable between an operative configuration and an inoperative configuration, the inoperative configuration being such that the arm may pass the formation without engaging therewith and the operative configuration being such that the arm abuts the formation and is unable to pass thereby. The formation may be raised relative to the body in the operative configuration and may be retracted relative to the body or coplanar with the body in the inoperative configuration. The formation is preferably in the inoperative configuration when the pendulum bob is at the first position, and is preferably reconfigured to the operative configuration at least before the pendulum bob has reaches the second position. Preferably the trigger means is arranged to reconfigure the formation from the inoperative configuration to the operative configuration. The trigger means may be arranged to disengage the locking means to enable the gravitational force acting on the formation to drive rotation of the body about the second rotation axis. Alternatively, or in addition thereto, the trigger means may be arranged to energise the motor for rotating the body portion about the second rotation axis. Alternatively, the formation may remain fixed. In this arrangement a moveable plate located on the upper portion of a pendulum arm is arranged to allow the pendulum arm to pass the formation when in an open position, with the locking means disengaged, and once the body is released about the second rotation axis. With the locking means disengaged the formation abuts the plate that has been triggered to close, in order to apply a force to the pendulum arm.

A second assisted pendulum device may be provided, the second assisted pendulum device comprising a pendulum arm, wherein the first and second assisted pendulum devices are arranged such that the pendulum bob of the first assisted pendulum device decouples from the arm of the first assisted pendulum device at the third position thereof and couples to the arm of the second assisted pendulum device, the position at which the pendulum bob couples to the arm of the second assisted pendulum device defining the first position of the second assisted pendulum device.

The second assisted pendulum device may comprise any of the above-described features.

Alternatively, or in addition thereto, the second pendulum device may comprise a second pendulum bob and may be arranged such that material contained within the pendulum bob of the first assisted pendulum device passes from the pendulum bob of the first assisted pendulum device to the pendulum bob of the second assisted pendulum device at the third position of the former. The position at which the material enters the pendulum bob of the second assisted pendulum device may define the first position of the second assisted pendulum device. Alternatively, the pendulum bob of the second assisted pendulum device may be subsequently raised to the first position after the material has been introduced to the pendulum bob.

Preferably the assisted pendulum devices are positioned on an inclined surface such that the axis of rotation of the pendulum arm of the second pendulum device is positioned at a greater height than the axis of rotation of the pendulum arm of the first assisted pendulum device.

Further assisted pendulum devices may be provided and arranged such that a pendulum bob may travel from one device to another and/or material contained within a pendulum bob may travel from one device to another as described above.

It will be appreciated that the above-described system is suitable for transporting a pendulum bob, or the contents thereof, over an extended distance.

In accordance with the present invention, as seen from a second aspect, there is provided a method of transporting material, the method comprising the steps of: providing assistance means as hereinbefore described;

coupling said material to a pendulum arm and releasing said material, coupled to said pendulum arm, from a first position; and,

engaging the assistance means with the pendulum arm at least prior to said material reaching a position in which the gravitational potential energy of the pendulum provided by the said material at the first position has been exhausted. Said material may define a pendulum bob, which may be directly coupled to the pendulum arm. Alternatively, the step of coupling the material to the pendulum arm may comprise introducing the material to a cavity within a pendulum bob, the pendulum bob being fixedly or detachably coupled to the pendulum arm. The method may further comprise the step of decoupling said material from said pendulum arm, said step preferably being carried out after when said material is at a height greater than the height of the first position.

An embodiment of the present invention will now be described by way of example only and with reference to the accompanying drawings, in which: Figure 1 (a) is a side view of an assisted pendulum device in accordance with the present invention, the device being shown in the first position; Figure 1 (b) is a side view of the device of figure 1 (a), the device being shown in the lowermost position;

Figure 1 (c) is a side view of the device of figures 1 (a) and (b), the device being shown in a position in which the arm passes over the formation;

Figure 1 (d) is a side view of the device of figures 1 (a) to (c), the device being shown in the second position;

Figure 1 (e) is a side view of the device of figures 1 (a) to (d), the device being shown in the third position; and,

Figure 2 is a side view of an alternative embodiment of an assisted pendulum device in accordance with the present invention, the device being shown in the lowermost position;

Referring to figures 1 (a) to 1 (e) of the drawings, there is illustrated an assisted pendulum device 10 in accordance with an embodiment the present invention, the device being shown in a different position in each of figures. The device 10 comprises a pendulum arm 11 coupled at its proximal end to a substantially disc-like body 12. The arm 1 1 is pivotally coupled to the body 12 so as to allow rotation of the arm 1 1 about a first axis 13. The first rotation axis 13 is disposed intermediate proximal and distal ends of the arm 1 1 such that the first rotation axis 13 divides the arm 11 in to an upper portion and a lower portion. The arm 11 is displaced from the plane of the body 12 by a small distance so as to enable the arm 1 1 to rotate about the first axis 13 without frictionally engaging the body 12.

The body 12 is rotatable about a second axis 14 in a direction substantially perpendicular to the plane of the body 12. In the illustrated embodiment, the second axis 14 is located at the centre-point of the disc-like body 12. The second axis 14 is oriented substantially parallel the first axis 13 but is radially displaced therefrom. Accordingly, the first axis 13 is configured to pivot about the second axis 14 upon rotation of the body 12 about the latter. A distal end of the pendulum arm 1 1 is coupled to a pendulum bob 15. In one embodiment the pendulum bob 15 may be releasably coupled to the pendulum arm 1 1. In this embodiment the distal end of the pendulum arm 1 1 comprises means (not shown) for selectively engaging the pendulum bob 15. Said means may comprise a U-shaped bracket having upper and lower arms, a closed end in the direction of travel of the pendulum bob 15 and an open opposing end. Accordingly, as the pendulum arm 1 1 is raised to a certain threshold angle, the pendulum bob 15 may move, under the action of gravity, out of the open end of the U-shaped bracket. An alternative means for selectively engaging the pendulum bob 15 may comprise forming the pendulum bob 15 of a magnetic material and providing an electromagnet at the distal end of the pendulum arm 11.

Assistance means in the form of a formation is provided on the body 12 of the device 10. In the illustrated embodiment, the formation takes the form of an abutment 16 that may be raised and lowered in order to engage or disengage the formation with the pendulum arm 11. The abutment 16 illustrated in the figures comprises a cylindrical rod-like shape, but it will be appreciated that other shapes and sizes are within the scope of the present invention. It will also be appreciated that other formations that do not necessarily abut the pendulum arm 1 1 but engage therewith by an alternative means such as magnetic attraction or repulsion are within the scope of the present invention.

The abutment 16 is reconfigurable between an operative configuration and an inoperative configuration. In the operative configuration the abutment 16 protrudes outwardly from the plane of the body 12 to a distance at least equal to the distance between the arm 1 1 and the plane of the body 12 so as to enable the rod 16 to engage the arm 1 1. Conversely, in the inoperative configuration the abutment 16 is either recessed, coplanar with the plane of the body 12 or protrudes outwardly from the plane of the body 12 to a distance less than the distance between the arm 1 1 and the plane of the body 12. Accordingly, when the abutment 16 is in the inoperative configuration the arm 1 1 is able to pass over the abutment 16 without engaging therewith.

The assistance means further comprises external driving means in the form of a motor (not shown). The motor is configured to selectively rotate the body 12 of the device 10.

A trigger means (not shown) is arranged to reconfigure the abutment 16 between the operative and inoperative configurations. In particular, the trigger means is arranged to reconfigure the abutment 16 from the inoperative configuration to the operative configuration once the upper portion of the arm 1 1 has moved from a proximal side of the abutment 16 with respect to the direction of motion of the upper portion of the arm 11 to a distal side of the abutment 16 with respect to the direction of motion of the upper portion of the arm 1 1. The trigger means is further arranged to engage the motor to drive rotation of the body 12 and disengage the motor to cease rotation of the body 12. In particular, the trigger means is arranged to engage the motor once the abutment 16 has been reconfigured to the operative configuration and disengage the motor once the pendulum bob 15 has reached the desired height. The trigger means of the illustrated embodiment comprises a sensor arranged to detect the pendulum arm 1 1 as it passes in front of the abutment 16, as illustrated in figure 1 (c). The trigger means may, for example, comprise a light sensor disposed within the abutment 16 and configured to detect the reduction in light caused by the arm 1 1 passing thereover. Alternatively, the trigger means may comprise copper brushes arranged to contact the arm 1 1 at a given position thereof, the copper brushes being configured to pass a current through the arm 1 1 to complete an electric circuit.

In use, the pendulum is bob 15 is coupled to the pendulum arm 11 and raised to a first position having a first height hi , as illustrated in figure 1 (a). Alternatively, the arm 1 1 may be raised prior to coupling the bob 15 thereto, the bob 15 being coupled at the first height hi . When in the first position, the abutment 16 is in the inoperative configuration i.e. is in the configuration that enables the upper portion of the arm 11 to pass the abutment 16 without any physical contact therebetween. The pendulum bob 15, coupled to the pendulum arm 1 1 , is then released from the first height hi and allowed to swing downwardly under the action of gravity. In the figures, the first position is shown left of the axis of rotation 13 of the pendulum arm 1 1 and thus the bob 15 swings in a anticlockwise direction.

Figure 1 (b) illustrates the lowermost position of the pendulum bob 15. The pendulum bob 15 passes through this position, the kinetic energy of the bob 15 at the lowermost position being converted into gravitational potential energy as the bob 15 moves upwardly towards the second position illustrated in figure 1 (d).

Initially, the upper portion of the pendulum arm 1 1 initially moves towards the abutment 16 as the pendulum bob 15 swings downwardly, the pendulum arm 11 subsequently passing the abutment 16 as the pendulum bob swings from the first position to the second position illustrated in figure 1 (d). Figure 1 (c) illustrates the position in which the upper portion of the arm 11 crosses the abutment 16. At this point the abutment 16 is still in the inoperative configuration 16 so the upper portion of the arm 1 1 does not contact the abutment; rather, the upper portion of the arm 11 is allowed to fully pass the abutment 16. After the upper portion of the pendulum arm 1 1 has fully passed the abutment 16, the abutment is reconfigured to the operative configuration, which in the illustrated embodiment comprises raising the abutment to a height at least equal to the spacing between the plane of the body 12 and the pendulum arm 1 1. This reconfiguration is initiated by the trigger means, which in the illustrated embodiment comprises a sensor. Figure 1 (d) illustrates a second position of the pendulum bob 15. In this position, the pendulum bob 15 has reached a second height i2, which is the maximum height that is attainable under the natural i.e. unassisted swing of the pendulum. The second height i2 is substantially equal to the first height hi providing frictional loses are minimal. In the absence of the assistance means, the pendulum bob 15 would come to a momentary stop at the second position and subsequently fall downwardly in an opposite angular direction to the angular direction of travel between the first and second positions i.e. in an clockwise direction. However, the assistance means of the present invention prevent this from occurring: the abutment 16 is engaged with the upper end of the arm 11 at the second position and acts to prevent clockwise rotation of the arm 11 about the first axis 13. In addition, the trigger means energises the motor, which causes the body 12 to rotate anticlockwise about the second axis 14. Since the abutment 16 prevents rotation of the arm 1 1 relative to the body 12, the anticlockwise rotation of the body 12 is translated into anticlockwise rotation of the pendulum bob 15. The pendulum bob 15 is therefore driven upwardly from the second position, to a third position illustrated as illustrated in figure 1 (e). The height of the third position hz may be varied by carrying the length of time for which the motor is engaged. Importantly, the height of the third position hz is greater than the height of the second position i2 and hence greater than the height of the first position hi . In this way, the assistance means has increased the height of the pendulum bob 15.

Once the pendulum bob 15 has reached the third position, it may be disengaged with the pendulum arm 1 1. A different pendulum bob may be engaged with the arm 1 1 in its place or the arm 1 1 may be left without a pendulum bob. The trigger means may be configured to detect when the pendulum bob 15 has been disengaged and trigger reconfiguration of the abutment 16 from the operative configuration to the inoperative configuration upon detection of disengagement of the pendulum bob. Once the abutment 16 has been reconfigured to the inoperative configuration, the pendulum arm 1 1 rotates clockwise under the action of gravity. It is envisaged that no assistance will be provided in the clockwise direction and that the angular positions of the first axis 13 and abutment 16 about the second axis 14 will be reset during the clockwise swing such that the pendulum device 10 comprises a continuous cycle having a period defined by an anticlockwise and clockwise swing. However, other embodiments are possible in which the assistance means is arranged to assist the pendulum arm and/or bob in both the clockwise and anticlockwise swings.

In an alternative embodiment, the device comprises the above-described with the exception of a motor. Instead of a motor or other external driving means, a weighted member is fixedly coupled to the body, said weighted member either being integral with the abutment 16 or separated therefrom and having a mass similar to or greater than that of the pendulum bob 15. For example, the device could be substantially identical to that shown in figures 1 (a) to 1 (e), with the abutment 16 comprising a weighted member. In this embodiment, a reduction in height of the weighted member provides for an increase in height of the pendulum bob 15. It will be appreciated that the increase in height of the pendulum bob 15 (Ahbob) is dictated by the decrease in height of the abutment (Ahabutment) and the relative masses of the abutment (m _a butment) and the pendulum bob 15 (rribob):

Ahbob ⁼ Ahabutment ^' (fTlabutment / mbob) In the illustrated embodiment, a radial line from the second axis 14 to the abutment 16 forms an angle Θ of approximately 120 degrees with respect to the vertical when the device 10 is located at the first position as illustrated in figure 1 (a). However, the skilled person will appreciate that said angle Θ is not limited to 120 degrees; any angle other than 0 degrees would enable the formation 16 to move downwardly as the body 12 of the pendulum device 10 rotates from the first position, this reduction in gravitational potential energy of the abutment 16 at the third position relative to the first position facilitating an increase in gravitational potential energy of the pendulum bob 15 at the third position relative to the first position. A releasable locking mechanism (not shown) in the form of a brake such as a disc brake is provided for selectively preventing rotation of the body 12 about the second axis 14. It will be appreciated, however, that the locking mechanism may alternatively take the form of a releasable clamp or other releasable locking or braking mechanisms known in the art. The disc brake is arranged to substantially prevent rotation of the body 12 about the second rotation axis 14 when engaged and permit rotation of the body 12 about the second rotation axis 14 when disengaged.

In the above-described alternative embodiment, the trigger means is arranged to reconfigure the abutment 16 from inoperative configuration to the operative configuration and is further arranged to disengage the brake to enable the gravitational force acting on the abutment 16 to drive rotation of the body 12 about the second rotation axis 14.

With reference to figure 2, in an alternative embodiment of the present invention, the assisted pendulum device 100 comprises an arm 1 11 arranged to rotate about a first axis 113, the first axis being spatially fixed. The arm 111 is coupled at its lower end to a pendulum bob 1 15. Assistance means in the form of a hammer 117 is provided, the hammer 1 17 being arranged to rotate about an a substantially vertical axis to strike the pendulum bob 1 15 and/or pendulum arm 1 11 as the pendulum bob 1 15 travels from the first position to the second position. Since the pendulum bob rotates about a substantially horizontal axis 1 13, the rotation of the hammer 117 about the vertical axis will ensure that the hammer 1 17 does not interfere with the swing of the pendulum bob 115 prior to the hammer 1 17 striking the pendulum arm 11 1. It will be appreciated that the striking action of the hammer 117 increases the kinetic energy of the pendulum bob 1 15 and thus enables the bob to reach a greater final height than the initial height thereof.

The hammer may be arranged to strike the pendulum bob and/or pendulum arm in accordance with a signal received from trigger means such as the sensor described in relation to the embodiment illustrated in figures 1 (a) to 1 (e).