A gravitational battery system and components therefor

Abstract

In a first aspect, the present invention relates to a gravitational battery system comprising a substantially vertical shaft having an upper and lower location, a vertical transport means connected to a motor-generator, a gripper assembly mechanically connected to the vertical transport means and arranged to be raised and lowered along the shaft, and at least one weighted object. Also provided in a further aspect is a gripper assembly to grip and suspend a weighted object, comprising a gripper body, at least two gripper arms actuatable in a gripping and an opening direction, an engaging portion on a second end of each of the at least two gripper arms, and a secondary frame connected to each of the at least two gripper arms.

Description

A GRAVI TATI ONAL BATTERY SYSTEM AN D COMPON ENTS THEREFORPRI ORI TY CLAI M

[0001] The present application claims priority from AU 2023900644, filed in Australia on 9 March 2023. The contents of the priority application are hereby incorporated herein by reference.TECHNI CAL Fl ELD

[0002] The present invention relates generally to the field of gripper assemblies and more particularly to the field of gripper assemblies for raising and lowering objects down vertical shafts.BACKGROUN D

[0003] The principle of a gravitational battery is to take advantage of the change in gravitational potential energy by moving a mass vertically through the gravitational field. By hoisting a weight to an upper location at one point in time energy can be converted into a potential. By releasing the weight to a lower location at another point in time the potential can be reconverted into electrical energy.

[0004] The present invention was motivated in part by a desire to convert legacy m ines into providers of green energy, in particular through the repurposing of disused m ine shafts. The gravitational battery of the present invention was therefore informed in part by the need to install the battery in a brownfield setting where a range of conditions exist that are not ideally suited to battery design.

[0005] I n broad terms, considerations of the present invention included the minim isation of complexity, the minimisation of cost including through modular design, the use of proven technologies where possible, the minim isation of inshaft installation, the minim isation of shaft access requirements, the minim isation of maintenance exposure, maxim isation of operating life, andcompatibility of design with the realities of remote operations. More particular problems are addressed below.

[0006] The selection of the weights used in the gravitational battery is a significant problem . The choice of weights influences the energy capacity of the gravitational battery and the equipment used to mobilise the weights. The issue of energy capacity favours the use of multiple weights with concom itant problems in how to stack, stow, and handle the multiple weights. These factors are further confounded by the selection of materials used in the fabrication of the weights and the available volume in the battery. A gravitational battery comprising m ultiple weights mobilised in a shaft necessitates a means for reliably stacking those weights at the bottom of the shaft. A vertical string of weights is potentially quite unstable, however there is a trade-off to be considered between the stability of the stacked weights and minim ising in-shaft installations. Weights suspended by cable also tend to rotate about a vertical axis and translate in one or more horizontal axes; degrees of motion which require control. The use of multiple weights also requires a means for reversibly coupling the weights to the hoist, which is not a straightforward problem in a vertical shaft since the coupling means m ust be operated blind at the bottom of the shaft. Furthermore, the coupling means must be highly reliable due to the potentially catastrophic consequences of dropping heavy weights down onto shaft infrastructure.

[0007] Problems in the use of multiple weights are also encountered topside of the shaft. The weights m ust be mobilised horizontally at the upper end, which is problematic, firstly because it requires the reversible coupling of each individual weight to the hoist, and secondly because it requires a means for the horizontal transfer of the weights to and from the shaft. Also topside of the shaft, the logistical management of multiple weights in a laydown yard can be problematic. The number of weights required for the gravitational battery to be economic, as well as the rate at which those weights must be mobilised to and from the shaft to provide commercially feasible power output of for example 5MW, requires a handling means that is fit for purpose.

[0008] Problems are also encountered in the gripping mechanism . Prior art gripping mechanisms are typically impractical, complex and requiring power, which presents the issue of providing electricity as the gripping mechanism ascends or descends the mineshaft without increasing the static weight of the mechanism . As the static weight of the gripping mechanism is constant, it does not contribute to the ability of the system to store or release electricity through gravitational potential energy, and therefore there is a need to provide a reliable gripping mechanism that reduces complexity and / or does not require power.

[0009] The present invention arose out of a desire to overcome or at least ameliorate some of the deficiencies of the prior art.DI SCLOSURE OF THE I NVENTI ON

[0010] I n a first aspect, the present invention relates to a gravitational battery system comprising a substantially vertical shaft having an upper location and a lower location, a vertical transport means connected to a motor-generator, a gripper assembly comprising gripper arms, the gripper assembly being mechanically connected to the vertical transport means and arranged to be raised and lowered along the shaft between the upper and lower locations, at least one weighted object adapted to be gripped by and suspended from the gripper arms of the gripper assembly, a first laydown area, proximal to the upper location of the shaft, for storing the at least one weighted object, and a second laydown area, proximal to the lower location of the shaft, for storing the at least one weighted object. I n an embodiment, the lowering of the gripper assembly by the vertical transport means drives the motor-generator to operate as a generator, and operating the motor-generator as a motor drives the vertical transport means to raise the gripper assembly.

[0011] I n an embodiment, the vertical transport means comprises a cable winder rotatably connected to the motor-generator with at least one cable cooperating with the winder.

[0012] I n an embodiment, the shaft is provided with a means for guiding the gripper assembly, with one of the at least one weighted objects gripped thereby and suspended therefrom , to the second laydown area.

[0013] I n an embodiment, the weighted object comprises an upper portion, a body portion, and a base portion. I n an embodiment, at least one of the upper portion, base portion and / or the body portion are detachable from the weighted object. I n an alternate embodiment, the weighted object is essentially monolithic.

[0014] I n an embodiment, the gravitational battery system further comprises at least one fastening means arranged to fasten the upper portion and base portion together such that the body portion is clamped between the upper portion and base portion.

[0015] I n an embodiment, the upper portion comprises an upper surface adapted to receive a base portion of a further object that is stacked thereupon.

[0016] I n an embodiment, the upper portion comprises a prom inence upwardly extending from the upper surface, and the base portion comprises a complementary recess on an underside thereof.

[0017] I n an embodiment, the upper portion is shaped to outwardly extend beyond a circumference of the body portion in at least one horizontal direction, thereby forming at least one peripheral region thereof, and the weighted object is gripped and suspended by an engaging portion of one of the gripper arms of the gripper assembly upwardly bearing against an underside of the at least one peripheral region.

[0018] I n an embodiment, the upper portion or body portion comprises a pair of opposing apertures, each adapted to receive an engaging portion of one of the gripper arms of the gripper assembly. I n an embodiment, the opposing apertures are connected to one another through the weighted object.

[0019] I n an embodiment, at least the body portion of the weighted object comprises a spool, coil or reel of material.

[0020] I n an embodiment, the body portion is formed from a plurality of stacked elements arranged between the upper and base portions.

[0021] A further aspect of the present invention may lie in a gripper assembly to grip and suspend a weighted object, comprising a gripper body, at least two gripper arms downwardly extending therefrom and actuatable in a gripping direction and an opening direction, each gripper arm having a first end and second end, a primary connection between the gripper body and the first end of each of the at least two gripper arms, an engaging portion on the second end of each of the at least two gripper arms, and a secondary frame connected to each of the at least two gripper arms by a secondary connection, the secondary frame being mobile, relative to the gripper body, in a first and a second, opposing, direction. I n an embodiment, the primary and secondary connections are flexible and are adapted such that relative movement of the secondary frame in the first or second direction induces actuation of the at least two gripper arms in the gripping or opening direction, respectively, and actuation of the at least two gripper arms in the gripping or opening direction induces relative movement of the secondary frame in the first or second direction, respectively.

[0022] I n an embodiment, each gripper arm comprises a spacer portion that extends at least partially laterally outward from the first end.

[0023] I n an embodiment, the secondary frame is pivotably connected to each of the at least two gripper arms at a secondary connection location on the gripper arm that is arranged laterally outward with respect to the primary connection between the gripper body and the same gripper arm . I n an embodiment, the spacer portion extends between the first end and the secondary connection location. I n an embodiment, each gripper arm comprises an outwardly-extending protrusion, the secondary connection location being located thereupon.

[0024] I n an embodiment, the secondary frame is movable between a first and second position, the second position is in the second direction from the first position, and the gripper assembly is adapted such that the secondary frame is biased to move, in the first direction, towards the first position. I n an embodiment, the first position is below the second position, such that the secondary frame is at least partially biased to move in the first direction by gravity.

[0025] I n an embodiment, the gripper assembly further comprises at least one resiliently-flexible return structure arranged to bias the secondary frame to move in the first direction. I n an embodiment, the resiliently-flexible return structure comprises a spring mechanism .

[0026] I n an embodiment, the gripper assembly further comprises a locking means arranged to temporarily and reversibly lock the secondary frame in the second position. I n an embodiment, the locking means comprises a first and second latch component, the first latch component being mounted to the secondary frame and the second latch component being mounted to the gripper body, and a driving means arranged to drive the first latch component into and / or out of latching fit with the second latch component when the secondary frame is in the second position. I n an embodiment, the driving means comprises a driving rod and a cam mechanism , the driving rod is slidable with respect to at least one of the gripper body and the secondary frame, and being arranged to actuate the cam mechanism upon sliding, and the actuatable cam mechanism is arranged to drive the first latch component upon actuation thereof.

[0027] I n an embodiment, the primary connection between each of the at least two gripper arms and the gripper body is a double-hinge connection comprising a linkage hingedly connected at an end thereof to the gripper body and hingedly connected at an opposing end to the first end of the respective gripper arm .

[0028] I n an embodiment, the secondary connection between each of the at least two gripper arms and the secondary frame is a pivotable connection.

[0029] I n an embodiment, the engaging portion of each of the at least two gripper arms is shaped to comprise a downwardly- and inwardly- facing guide surface adapted to bear against an outer edge of an upper surface of an object to be gripped as the gripper assembly is lowered thereover. I n an embodiment, the guide surface is shaped such that, as the object to be gripped upwardly bears thereagainst, the at least two gripper arms are urged to actuate outwardly in the opening direction.

[0030] I n an embodiment, the engaging portion of each of the at least two gripper arms is shaped to comprise an upwardly-angled surface arranged to upwardly bear against a surface of the object when the particular gripper arm is in the gripping configuration.

[0031] I n an embodiment, the gripper assembly may be used as a coupling means of a gravitational battery, the object being a massive weight thereof.

[0032] Further or alternative embodiments of the invention may be disclosed herein or may otherwise become apparent to the person skilled in the art through the disclosure herein. These and other embodiments are considered to fall within the scope and object of the invention.DESCRI PTI ON OF Fl GURES

[0033] Embodiments of the present invention will now be described in relation to figures, wherein:Figure 1 is a diagram of an embodiment of a gravitational battery system of the present invention;Figure 2 is an embodiment of a guiding means thereof;Figures 3-5 depict various embodiments of a weighted object thereof;Figure 6 depicts an embodiment of a gripping assembly of a second aspect of the invention;Figures 7A-7C depict various embodiments of gripper arms thereof;Figures 8A & 8B depict embodiments of pivotable connections thereof;Figures 9 & 10 depict embodiments of the gripper assembly at different stages of opening and closing the gripper arms;Figure 1 1 depicts an embodiment of a return mechanism of the gripper assembly;Figure 12 depicts an embodiment of a guiding protrusion of the same;Figures 13- 18 depict a locking means of the same;Figures 19A & 19B depict an embodiment of a double-hinge mechanism employed by certain embodiments of the gripper assembly; andFigures 20A & 20B depict certain embodiments of an engaging portion of the gripper arms of the same.DETAI LED DESCRI PTI ON OF PREFERRED EMBODI MENTS

[0034] I n a first aspect, the present invention may comprise a gravitational battery system comprising a substantially vertical shaft and a means of raising or lowering weighted objects along the shaft, wherein lowering of the weighted object drives a motor-generator to operate as a generator (thereby discharging electrical power from the battery) .

[0035] I n an embodiment and with reference to Figure 1 there is depicted a gravitational battery system 10 arranged for storing energy from , or releasing energy to, an electrical grid (not shown) . The system 10 may comprise a substantially vertical shaft 12 having an upper location 12A and a lower location 12B, a vertical transport means 14 that is electrically connected to a motorgenerator 16, a gripper assembly 18 that is mechanically connected to the vertical transport means 14 and arranged to be raised and lowered along the shaft between the upper and lower locations, and at least one weighted object 20 adapted to be gripped by and suspended from the gripper assembly. I n an embodiment, the gripper assembly 18 may comprise at least a pair of gripper arms with which to grip the weighted object 20. The system may further comprise a first laydown area 22, which is proximal to the upper location 12A of the shaft 12, for storing the at least one weighted object, and a second laydown area 24, which is located at or proximal to the lower location 12B of the shaft 12, for storing the at least one weighted object after it has been lowered.

[0036] I n an embodiment, the electrical connection between the motorgenerator 16 and the electrical grid, and the connection between the motor-generator 16 and vertical transport means 14, are each configured such that the motor-generator is able to draw electricity from the electrical grid in order to operate as a motor, thereby driving the vertical transport means to raise the gripper assembly (and a weighted object gripped thereby) , and store the drawn electricity as gravitational potential energy in the raised weighted object 20. Furthermore, the vertical transport means 14 lowering the weighted object 20 drives the motor-generator 16 to operate as a generator, thereby converting the stored gravitational potential energy into electricity which is subsequently able to be released into the electrical grid.

[0037] I n an embodiment, the vertical transport means may comprise a cable wound around a cable winder 14A that is rotatably connected to the motorgenerator 16.

[0038] Turning to Figure 2, in an embodiment the shaft 12 may be provided with a guiding means 26 arranged to guide the vertical movement of the gripper assembly 18 therealong and towards the second laydown area 24. I n an embodiment, the guiding means 26 may comprise one or more substantially rigid guides 28 that are each configured to inhibit or restrict movement of the gripper assembly 18 in a corresponding horizontal direction.

[0039] I n a further embodiment, the rigid guides 28 may comprise rails, tracks, or runners. I n a further embodiment, the guiding means 26 may comprise at least one pair 30 of guides 28 arranged to receive a portion of the gripper assembly 18 therewithin. I n a further embodiment, the guiding means 26 may comprise more than one pair 30 of guides 28, each configured to accommodate a different portion of the gripper assembly therebetween. I n an embodiment, the guiding means 26 extends for at least a substantial portion of the length of the vertical shaft 12.The Weighted Object

[0040] I n an embodiment and with reference to Figs. 3 & 4, the weighted object 20 may comprise an upper portion 32, a body portion 34, and a base portion 36.

[0041] I n an embodiment and with particular reference to Fig. 3, at least one of the upper portion 32, base portion 36 and / or the body portion 34 may be detachable from the weighted object 20. I n an embodiment, the weighted object 20 may further comprise at least one fastening means 38 arranged to fasten the upper portion 32 and base portion 36 together, such that the body portion 34 is clamped therebetween. I n a further embodiment, the weighted object may be essentially able to be disassembled. This may improve the ability for the weighted object 20 to be transported, stored, maintained or modified as necessary. I n an alternate embodiment, then weighted object 20 may be essentially monolithic and not adapted to be disassembled.

[0042] I n an embodiment and with reference to Figs. 3 & 4, the upper portion 32 may comprise an upper surface 40 that is adapted to receive a base portion 36 of a further object 20 that is stacked thereupon. Such an adaptation may, for example, comprise a flat upper surface. I n a further embodiment and with particular reference to Figure 4, the adaptation may at least partially comprise a prominence 42 that is upwardly extending from the upper surface 40. The base portion may comprise a complementary recess (not visible) on an underside thereof.

[0043] With return reference to Fig. 3, in an embodiment the upper portion 32 may be shaped to outwardly extend beyond a circumference of the body portion 34 in at least one horizontal direction, thereby forming at least one peripheral region 32A thereof. I n such an embodiment, the weighted object 20 may be gripped and suspended by an engaging portion of a gripper arm of the gripper assembly 18 upwardly bearing against an underside 44 of the at least one peripheral region.

[0044] With return reference to Fig. 4, in an alternate embodiment the upper portion 32 or body portion 34 may comprise a pair of opposing apertures 46, each adapted to receive an engaging portion of one of the gripper arms of the gripper assembly therewithin. I n a further embodiment, the opposing apertures 46 may be connected to one another through the weighted object 20.

[0045] I n an embodiment and as depicted in Fig. 3, the body portion 34 may be formed from a plurality of stacked elements arranged between the upper and base portions. Such an embodiment may enable the weight of the weighted object to be adjusted depending upon the demands placed upon the gravitational battery system .

[0046] I n an embodiment, at least the body portion 34 of the weighted object 20 may comprises a spool, coil or reel of material. Said spool, coil or reel may be encased in a casing. I n an embodiment, the body portion may be formed from a coil of rolled steel, with the horizontal apertures 46 residing at the centre of the steel coil. The steel coils may be fabricated from standardised steel m ill coils. As depicted in Fig. 4, the body portion may be encased in a casing.

[0047] I n a further alternate embodiment and with reference to Figure 5, the body portion 34 may comprise a hollow outer casing that is able to be packed or filled with a filler material 34A. Figure 5 depicts an embodiment of the weighted object 20 (top) and a cross-section thereof along line A-A (bottom) . By way of non-lim iting example, the filler material may be waste material such as slag, excess construction material, or similar; metallic material such as weights, scrap metal, ingots, or metal dust (sintered or unsintered) ; cementitious material; rock, gravel, sand and / or other ground material, including spent or waste material generated by mining; and so on. The body portion 34 may be sealed in order to contain the filler material 34A. The sealing of the body portion 34 may be by the upper portion 32 and / or the base portion 36 (as depicted in Figure 5) , or the body portion 34 may be a self-contained casing with the upper and base portions 32, 36 affixed thereto.The Gripper Assembly

[0048] A further aspect of the invention may lie in a gripper assembly to grip and suspend a weighted object. I n an embodiment and with reference to Fig. 6, the gripper assembly 100 may comprise a gripper body 102, at least two gripper arms 104 downwardly extending therefrom , and a secondary frame 106 connected to each of the at least two gripper arms.

[0049] I n an embodiment, the gripper assembly 100 may be used as a coupling means of a gravitational battery system . I n a further embodiment, the gripper assembly 100 may be a gripper assembly 18 of an embodiment of a gravitational battery system 10 of the first aspect of the present invention.

[0050] I n an embodiment, the gripper arms 104 may be actuatable in a gripping direction and an opening direction, as indicated by the curved, doubleheaded arrow in Fig. 6. The gripping direction may comprise movement of the at least two gripper arms 104 inwardly, or otherwise towards one another. The opening direction may comprise movement in an opposing direction to the gripping direction.

[0051] I n an embodiment, each gripper arm may comprise a first end 104A and second end 104B. I n an embodiment, the gripper assembly may comprise a primary connection 108 between the gripper body 102 and the first end 104A of each of the at least two gripper arms. I n such an embodiment, the connection between the secondary frame 106 and each of the at least two gripper arms 104 may be a secondary connection 1 10. I n an embodiment, the secondary connection 1 10 between each of the at least two gripper arms 104 and the secondary frame 106 may be a pivotable connection.

[0052] I n an embodiment, the gripper arms may each comprise an engaging portion 1 12 on the second end 104B thereof. I n an embodiment and with reference to Figs 6 & 7A-7C, the gripper arms 104 may be shaped to pick up and grip a weighted object 1 14 therebetween. As the skilled person will appreciate, the gripper arms 104 depicted in Fig. 6 have an engaging portion 1 12 that is shaped to engage with a surface 1 14B of the object 1 14, but this is exemplary only. As per Figures 6A-6C, the engaging portion 1 12 may comprise a variety of forms depending upon the shape, material and orientation of the weighted object 1 14 that is to be gripped and suspended, without departing from the scope and / or object of the invention described herein.

[0053] I n an embodiment, the secondary frame 106 may be mobile, relative to the gripper body 102, in a first and a second direction, depicted in Fig. 6 as a vertical double-headed arrow. The second direction may be an opposingdirection to the first direction. I n a further embodiment, the primary and secondary connections 108, 1 10 are flexible and are adapted such that relative movement of the secondary frame 106 in the first or second direction induces actuation of the at least two gripper arms 104 in the gripping or opening direction, respectively, and actuation of the at least two gripper arms 104 in the gripping or opening direction induces relative movement of the secondary frame 106 in the first or second direction, respectively. I n such an embodiment, actuation or movement of either the gripper arms or the secondary frame induces movement of the other.

[0054] I n an embodiment and with particular reference to Figs. 7B & 7C, each gripper arm 104 may comprise a spacer portion 1 16 that extends at least partially laterally outward from the first end 104A. As depicted, the spacer portion 1 16 does not need to extend perfectly laterally or have a specific shape, but rather merely adds outward lateral spacing to a portion of the gripper arm 104. I n particular, the spacer portion 1 16 may be shaped and / or arranged such that the second end 104B of the gripper arm 104 is arranged laterally outward with respect to the first end 104A. This may, for example, promote improved leverage, or may enable wide objects to be gripped and suspended without increasing the overall size profile of the gripper assembly 100

[0055] I n an embodiment and with reference to Figs. 8A & 8B, the secondary frame 106 may be connected to each of the at least two gripper arms 104 at a secondary connection location 1 10A on the gripper arm that is arranged laterally outward with respect to the primary connection 108 between the gripper body 102 and the same gripper arm . With reference to Figure 8A, in an embodiment the secondary connection location 1 10A may be on a protrusion 1 18 extending laterally outward from the gripper arm 104. The protrusion 1 18 may therefore support the secondary connection location 1 10A laterally outward with respect to the primary connection 108 between the gripper body 102 and the same gripper arm 104. With reference to Figure 8B, in an embodiment wherein the gripper arm 104 comprises an at least partially laterally extending spacer portion 1 16, the spacer portion 1 16 may extend between the first end 104A and the secondary connection location 1 10A. The skilled person will appreciate that the presence of a protrusion 1 18 is not m utually exclusive with the presence of aspacer portion 1 16, and an embodiment of the gripper arm 104 may comprise both.

[0056] I n an embodiment and with reference to Figs. 9 & 10, the secondary frame 106 may be movable between a first and second position 106- 1 , 106-2. The second position 106-2 is in the second direction from the first position 106- 1 . I n a further embodiment, the gripper assembly 100 is adapted such that the secondary frame 106 is biased to move in the first direction and thus towards the first position 106- 1 . Figs. 8 & 9 depict two different embodiments of primary connections 108.

[0057] I n one further embodiment, the first position 106-1 may be below the second position 106-2, such that the secondary frame 106 is at least partially biased to move in the first direction by gravity. For example, as the gripper arms 104 move outward the secondary frame 106 is elevated against gravity. The weight of the secondary frame 106 may therefore act to urge the gripper arms 104 inwards and therefore moving in a gripping direction. I n a second further embodiment and with reference to Figs 10, the gripper assembly 100 may comprise at least one resiliently-flexible return structure 120 that is arranged to bias the secondary frame 106 to move in the first direction. As depicted in Fig 10, the resiliently-flexible return structure 120 may be mounted to the gripper body 102, may be mounted to the secondary frame 106, or may be between the secondary frame 106 and the gripper arms 104. Further embodiments may include m ultiple arrangements of the resiliently-flexible return structure 120. I n a further embodiment, the resiliently-flexible return structure 120 may comprise a spring mechanism .

[0058] I n a further embodiment, the gripper assembly may be adapted so that the secondary frame 106 is at least partially biased to move in the first direction both by gravity and by a resiliently-flexible return structure 120.

[0059] I n an embodiment and with reference to Fig. 12, the secondary frame 106 may comprise a guiding protrusion 106A that downwardly extends therefrom . I n an embodiment, the guiding protrusion 106A may be adapted to bear against an upper surface 1 14A of the object 1 14. Said guiding protrusion106A may be adapted or arranged to help centre or position the gripper assembly 100 in an appropriate position above the object. I n an embodiment, said guiding protrusion 106A may be adapted or arranged to bear against the upper surface 1 14A of the object 1 14 when the secondary frame 106 is at a desired height thereabove.

[0060] I n an embodiment and with reference to Figs. 13 & 14, the gripper assembly may further comprise a locking means 122 that is arranged to temporarily and reversibly lock the secondary frame 106 in the second position 106-2 (known hereafter as the ‘locking configuration’) . I n a further embodiment and with particular reference to Fig 14, the locking means 122 may further comprise a first and complementary second latch component 124,126, the first latch component 124 being mounted to the secondary frame 106 and the second latch component 126 being mounted to the gripper body 102. The first and second latch components 124, 126 may latch together in a latching fit, thereby engaging the locking configuration.

[0061] The locking means 122 may further comprise a driving means 128 that is arranged to drive the first latch component 124 into and / or out of latching fit with the second latch component 126 when the secondary frame 106 is in the second position 106-2. I n a further embodiment, the driving means 128 may comprise a driving rod 130 and a cam mechanism 132. The driving rod 130 may slidably mounted to, and be slidable with respect to, at least one of the gripper body 102 and the secondary frame 106, and may be arranged to actuate the cam mechanism 132 upon sliding. I n such an embodiment, the actuatable cam mechanism 132 may be arranged to drive the first latch component 124 upon being actuated. I n a further embodiment, the gripper assembly 100 may be arranged such that opening the gripper arms 104 enough to extend around and subsequently grip a weighted object of a particular size does not induce sufficient relative movement of the secondary frame 106 to reach the second position 106-2. The person skilled in the art will appreciate that the gripper assembly may be resized in order to grip weighted objects of different sizes and that such a modification does not represent a departure from the object of the invention.Automated Gripping and Release Mechanism

[0062] I n an embodiment, the gripper assembly may be adapted to operate essentially autonomously and without the need for specific controls to actuate the at least two gripper arms 104.

[0063] This may be achieved by, in an embodiment, arranging the driving means 128 to drive the locking means 122 towards a locking configuration before the secondary frame 106 has reached the secondary position 106-2. As the secondary frame 106 is not in the second position 106-2, the locking means 122 will not be able to lock - but the locking means will engage and lock the secondary frame 106 into the second position 106-2 the moment that said second position is reached.

[0064] I n an embodiment, the driving means 128 is actuated by the weighted object 1 14, and begins to drive the locking means 122, either before or as the secondary frame 106 moves out of the first position 106- 1 and in the second direction (albeit without the locking means 122 being able to enter the locking configuration). The gripper assembly 100 may therefore grip and lift / suspend a weighted object 1 14 of a particular size, as opening the gripper arms 104 enough to extend around and subsequently grip the weighted object 1 14 of particular size does not induce sufficient relative movement of the secondary frame 106 to reach the second position 106-2.

[0065] The weighted object 1 14 may be released by moving the secondary frame 106 completely into the second position 106-2. When the secondary frame 106 is in the second position 106-2, the gripper arms 104 are actuated in the opening direction and, due to the locking means 122 entering the locking configuration, are held in an open state. As the driving means 128 is actuated by the weighted object 1 14, the driving means will continue to drive and hold the locking means 122 in the locking configuration, thereby retaining the secondary frame 106 in the second position 106-2 until the gripper assembly 100 is moved far enough away from the weighted object that the weighted object can no longer actuate the driving means 128, rather than the secondary frame 106im mediately returning towards the first position 106- 1 due to being biased to move in the first direction.

[0066] The above may now be explained through non-limiting example and with reference to Figs. 15 - 18. I n an embodiment wherein the driving means 128 comprises a slidable driving rod 130 and a cam mechanism 132, the driving rod may have a first rod position wherein it is not engaged with the cam mechanism 132. This first rod position may only be available when the gripper assembly 100 is not loaded with a weighted object 1 14 (See Fig. 15) . This may be achieved by, for example, arranging the slidable driving rod 130 such that a base of the driving rod, in the first rod position, sits either equal to or lower than where an upper surface 1 14A of a weighted object would be when gripped by the gripper assembly.

[0067] I n order to grip a weighted object 1 14 of a particular size, the gripper assembly may move towards said weighted object. The driving rod may be arranged to be slid out of the first rod position upon contacting an upper surface 1 14A of the weighted object 1 14 that is to be gripped and suspended by the gripper assembly 100. Upon sliding out of the first rod position, the cam mechanism 132 may subsequently be actuated, driving the locking means 122 towards a locking configuration. I n such an embodiment, the distance between the first and second positions 106- 1 , 106-2 may be configured to be greater than the distance that the secondary frame 106 moves in the second direction upon the gripper arms 104 opening to receive the weighted object 1 14 therewithin. By moving or lowering the gripper assembly enough that the gripper arms are actuated outwards to a sufficient degree to receive the weighted object but not so far that the secondary frame 106 reaches the second position 106-2, the locking means 122 will not be able to engage in the locking configuration. The secondary frame 106 will subsequently be biased to move in the first direction and back towards the first position 106- 1 , thereby inducing actuation of the at least two gripper arms 104 in the gripping direction, and ultimately gripping the weighted object 1 14 (See Fig. 16) . I n the example depicted in Fig. 16, the driving rod remains elevated out of the first position by the weighted object, and so the locking means 122 are being driven towards alocking configuration by the slidable driving rod 130 urging against the cam mechanism 132.

[0068] With reference to Fig. 17, release of the weighted object 1 14 may be achieved by inducing further movement of the gripper assembly 100 towards the weighted object 1 14. The secondary frame 106 may be impeded from moving any closer to the weighted object 1 14, and so the gripper body 102 will move towards the stationary secondary frame - in other words, the secondary frame 106 will move in the second direction relative to the gripper body 102. This may actuate the gripper arms 104 in the opening direction, releasing the weighted object 1 14. Further movement of the gripper assembly 100 towards the weighted object 1 14 will induce sufficient relative movement of the secondary frame 106 in the second direction to reach the second position 106-2, at which point the locking means 122 will engage in the locking configuration.

[0069] As the weighted object 1 14 is now released, the gripper assembly 100 may be moved away therefrom . With reference to Fig. 18, as the driving rod 130 is actuated by the weighted object 1 14, the driving rod 130 will continue to drive against the cam mechanism 132 until the gripper assembly 100 is far enough away from the weighted object that the driving rod can fully return to the first rod position ( Contrast Fig. 18 to Fig. 15) . This may prevent the secondary frame 106 from being im mediately biased in the first direction and / or the gripper arms 104 from moving in a gripping / closing direction once the weighted object 1 14 is no longer pressing, urging or resting thereagainst.

[0070] I n a further embodiment, the locking means 122 may further comprise a return mechanism 134 that is arranged to urge, drive or otherwise bias the locking means 122 into an unlocked configuration. With reference to Fig. 13, this may - for example - comprise a spring-return that is arranged to urge the first latch component 124 out of latching fit with the second latch component 126 when the driving force induced by the driving means 128 is either removed, negated or reversed.

[0071] I n an embodiment and with reference to Figures 19A & 19B, the hinged connection 136 between each of the at least two gripper arms 104 and thegripper body 102 may comprise a double-hinge connection 136. The doublehinge connection 136 may comprise a linkage 138 hingedly connected at an end 138A thereof to the gripper body 102 and hingedly connected at an opposing end 138B to the first end 104 of the respective gripper arm 104. Such an embodiment may provide additional mobility and / or flexibility to the motion of the at least two gripper arms 104.

[0072] I n an embodiment wherein the secondary frame 106 is pivotably connected to each of the at least two gripper arms 104 at a secondary connection location 1 10A, the use of a double-hinge connection 136 arrangement may enable the gripper arms 104 to at least partially swing inwardly and / or outwardly by pivoting about the second connection location 1 10A, with the linkage 138 providing the first end 104A of each gripper arm 104 with a capacity to move inwardly or outwardly with respect to the gripper body 102 as the second end 104B moves outwardly or inwardly, respectively.

[0073] I n an embodiment and with reference to Figure 20A, the second end 104B of each of the at least two gripper arms 104 may be shaped to comprise a downwardly-angled surface 140 arranged to induce outward movement in the respective gripper arm 104 when the weighted object 1 14 upwardly bears thereagainst. I n an embodiment and with reference to Figure 20B, the engaging portion 1 12 of each of the at least two gripper arms 104 may be shaped to comprise an upwardly-angled surface 142 that is arranged to upwardly bear against a surface 1 14B of the object 1 14 when the particular gripper arm 104 is in the gripping configuration. I n a further embodiment, the second end 104B and engaging portion 1 12 of each of the at least two gripper arms 104 may be shaped to comprise both the downwardly-angled surface 140 and the upwardly- angled surface 142.

[0074] While the invention has been described with reference to preferred embodiments above, it will be appreciated by those skilled in the art that it is not lim ited to those embodiments, but may be embodied in many other forms, variations and modifications other than those specifically described. The invention includes all such variation and modifications. The invention also includes all of the steps, features, components and / or devices referred to orindicated in the specification, individually or collectively and any and all combinations or any two or more of the steps or features.

[0075] I n this specification, unless the context clearly indicates otherwise, the word “comprising” is not intended to have the exclusive meaning of the word such as “consisting only of”, but rather has the non-exclusive meaning, in the sense of “including at least”. The same applies, with corresponding gram matical changes, to other forms of the word such as “comprise”, etc.

[0076] Other definitions for selected terms used herein may be found within the detailed description of the invention and apply throughout. Unless otherwise defined, all other scientific and technical terms used herein have the same meaning as com monly understood to one of ordinary skill in the art to which the invention belongs.

[0077] Any promises made in the present document should be understood to relate to some embodiments of the invention, and are not intended to be promises made about the invention in all embodiments. Where there are promises that are deemed to apply to all embodiments of the invention, the applicant / patentee reserves the right to later delete them from the description and they do not rely on these promises for the acceptance or subsequent grant of a patent in any country.

Claims

CLAI MS1 . A gravitational battery system comprising: a substantially vertical shaft having an upper location and a lower location; a vertical transport means connected to a motor-generator; a gripper assembly comprising gripper arms, the gripper assembly being mechanically connected to the vertical transport means and arranged to be raised and lowered along the shaft between the upper and lower locations; at least one weighted object adapted to be gripped by and suspended from the gripper arms of the gripper assembly; a first laydown area, proximal to the upper location of the shaft, for storing the at least one weighted object; and a second laydown area, proximal to the lower location of the shaft, for storing the at least one weighted object; wherein: the lowering of the gripper assembly by the vertical transport means drives the motor-generator to operate as a generator; and operating the motor-generator as a motor drives the vertical transport means to raise the gripper assembly.

2. The gravitational battery system of claim 1 , wherein the vertical transport means comprises a cable winder rotatably connected to the motorgenerator with at least one cable cooperating with the winder.

3. The gravitational battery system of claim 1 or 2, wherein the shaft is provided with a means for guiding the gripper assembly, with one of the at least one weighted objects gripped thereby and suspended therefrom , to the second laydown area.

4. The gravitational battery system of any one of claims 1 to 3, wherein the weighted object comprises an upper portion, a body portion, and a base portion.

5. The gravitational battery system of claim 4, wherein at least one of the upper portion, base portion and / or the body portion are detachable from the weighted object.

6. The gravitational battery system of claim 5, further comprising at least one fastening means arranged to fasten the upper portion and base portion together such that the body portion is clamped between the upper portion and base portion.

7. The gravitational battery system of any one of claims 4 to 6, wherein the upper portion comprises an upper surface adapted to receive a base portion of a further object that is stacked thereupon.

8. The gravitational battery system of any one of claims 4 to 7, wherein the upper portion comprises a prom inence upwardly extending from the upper surface; and the base portion comprises a complementary recess on an underside thereof.

9. The gravitational battery system of any one of claims 4 to 8, wherein the upper portion is shaped to outwardly extend beyond a circumference of the body portion in at least one horizontal direction, thereby form ing at least one peripheral region thereof; and the weighted object is gripped and suspended by an engaging portion of one of the gripper arms of the gripper assembly upwardly bearing against an underside of the at least one peripheral region.

10. The gravitational battery system of any one of claims 4 to 8, wherein the upper portion or body portion comprises a pair of opposing apertures, each adapted to receive an engaging portion of one of the gripper arms of the gripper assembly.1 1 . The gravitational battery system of claim 10, wherein the opposing apertures are connected to one another through the weighted object.

12. The gravitational battery system of any one of claims 4 to 1 1 , wherein at least the body portion of the weighted object comprises a spool, coil or reel of material.

13. The gravitational battery system of any one of claims 4 to 1 1 , wherein the body portion is formed from a plurality of stacked elements arranged between the upper and base portions.

14. A gripper assembly to grip and suspend a weighted object, the gripper assembly comprising: a gripper body; at least two gripper arms downwardly extending therefrom and actuatable in a gripping direction and an opening direction, each gripper arm having a first end and second end; a primary connection between the gripper body and the first end of each of the at least two gripper arms; an engaging portion on the second end of each of the at least two gripper arms; and a secondary frame connected to each of the at least two gripper arms by a secondary connection, the secondary frame being mobile, relative to the gripper body, in a first and a second, opposing, direction; wherein the primary and secondary connections are flexible and are adapted such that: relative movement of the secondary frame in the first or second direction induces actuation of the at least two gripper arms in the gripping or opening direction, respectively; and actuation of the at least two gripper arms in the gripping or opening direction induces relative movement of the secondary frame in the first or second direction, respectively.

15. The gripper assembly of claim 14, wherein each gripper arm comprises a spacer portion that extends at least partially laterally outward from the first end.

16. The gripper assembly of claim 14 or 15, wherein the secondary frame is pivotably connected to each of the at least two gripper arms at a secondary connection location on the gripper arm that is arranged laterally outward with respect to the primary connection between the gripper body and the same gripper arm .

17. The gripper assembly of claim 16 when dependent upon claim 15, wherein the spacer portion extends between the first end and the secondary connection location.

18. The gripper assembly of claim 16, wherein each gripper arm comprises an outwardly-extending protrusion, the secondary connection location being located thereupon.

19. The gripper assembly of any one of claims 14 to 18, wherein the secondary frame is movable between a first and second position; the second position is in the second direction from the first position; and the gripper assembly is adapted such that the secondary frame is biased to move, in the first direction, towards the first position.

20. The gripper assembly of claim 19, wherein the first position is below the second position, such that the secondary frame is at least partially biased to move in the first direction by gravity.21 . The gripper assembly of claim 19 or 20, further comprising at least one resiliently-flexible return structure arranged to bias the secondary frame to move in the first direction.

22. The gripper assembly of claim 21 , wherein the resiliently-flexible return structure comprises a spring mechanism .

23. The gripper assembly of any one of claims 19 to 22, further comprising a locking means arranged to temporarily and reversibly lock the secondary frame in the second position.

24. The gripper assembly of claim 23, wherein the locking means comprises: a first and second latch component, the first latch component being mounted to the secondary frame and the second latch component being mounted to the gripper body; and a driving means arranged to drive the first latch component into and / or out of latching fit with the second latch component when the secondary frame is in the second position.

25. The gripper assembly of claim 24, wherein the driving means comprises a driving rod and a cam mechanism ; the driving rod is slidable with respect to at least one of the gripper body and the secondary frame, and being arranged to actuate the cam mechanism upon sliding; and the actuatable cam mechanism is arranged to drive the first latch component upon actuation thereof.

26. The gripper assembly of any one of claims 14 to 25, wherein the primary connection between each of the at least two gripper arms and the gripper body is a double-hinge connection comprising a linkage hingedly connected at an end thereof to the gripper body and hingedly connected at an opposing end to the first end of the respective gripper arm .

27. The gripper assembly of any one of claims 14 to 26, wherein the secondary connection between each of the at least two gripper arms and the secondary frame is a pivotable connection.

28. The gripper assembly of any one of claims 14 to 27, wherein the engaging portion of each of the at least two gripper arms is shaped to comprise a downwardly- and inwardly- facing guide surface adapted to bear against anouter edge of an upper surface of an object to be gripped as the gripper assembly is lowered thereover.

29. The gripper assembly of claim 28 wherein the guide surface is shaped such that, as the object to be gripped upwardly bears thereagainst, the at least two gripper arms are urged to actuate outwardly in the opening direction.

30. The gripper assembly of any one of claims 14 to 29, wherein the engaging portion of each of the at least two gripper arms is shaped to comprise an upwardly-angled surface arranged to upwardly bear against a surface of the object when the particular gripper arm is in the gripping configuration.31 . The gripper assembly of any one of claims 14 to 30, when used as a coupling means of a gravitational battery, the object being a massive weight thereof.

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