AU2021250936B2

AU2021250936B2 - Trolley with Movable Shelves and a Self-Locking Mechanism

Info

Publication number: AU2021250936B2
Application number: AU2021250936A
Authority: AU
Inventors: Dean Bowd-Seeley; Greg Haydon; James Palmer Shaw; David John Wright; Geoffrey Lee Wright; Stephen Geoffrey Wright
Original assignee: Logan Cove Pty Ltd
Current assignee: Logan Cove Pty Ltd
Priority date: 2020-10-16
Filing date: 2021-10-14
Publication date: 2025-05-29
Anticipated expiration: 2041-10-14
Also published as: AU2021106973A4; ZA202107866B; AU2021250936A1

Abstract

A trolley comprising a mobile frame for supporting a plurality of shelves each for receiving a load, and a support mechanism for supporting the shelves and for moving the shelves in a circulating manner such that each of the shelves is moveable to a loading/unloading position, wherein the movement of the shelves is controlled by a self-locking worm drive. -1/6 2-2 Mn -Icz ZZS 1 i: 0 59 ucsz ltz,_ZWOMM Ma I Q N ls 10 d'zszItz sp;i ssz!--tz --A-b 5 M-SiSRIM-M m N k OMME 'R MW W4 Sz mm§ O-On k H% RNS-411M s N _ M- zz m _M,_MZM_ MMvidionl tM 12 24 i 38 ,26 12 Nn NV71 sz 30 YP_ 34 R M §:k Q E M H MS. Qz ZQZ: Mn tz::Z, -z g -psuzaz E MOO Vf 70 : !gg gngs m ON NOMr lpmrMm Q IN Zg!'Z'2*%, FS S-Z ERMA% M R_ MON -0 zQ2 MH zkM P 40 90 FIGURE 1

Description

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FIGURE 1

Trolley with Movable Shelves and a Self-Locking Mechanism

Field of the Invention

[0001] The present invention relates to a trolley with movable shelves and a self-locking mechanism.

Background

[0002] Mineral exploration involves identifying geological features worth mining. Commonly, in order to identify the presence and volume of a target geological feature, samples are extracted from a target geological feature for analysis. Often, the samples are cored from the geological feature using a core drill producing a generally cylindrical "core sample".

[0003] These core samples are often wet due to the presence of water in the geological feature and/or due to the use of water as a coolant/lubricant in the drilling operation to extract the core sample.

[0004] At present, these core samples are transported for drying on a multi-tray trolley. Due to the weight of the core samples, hand loading and unloading the trolley can involve bending to place or remove the heavy core sample at the appropriate level of the tray in the trolley. This creates an undesirable risk of injury.

[0005] The present invention seeks to provide an improved trolley.

[0006] The discussion of the background art is intended to facilitate an understanding of the present invention only. It should be appreciated that the discussion is not an acknowledgement or admission that any of the material referred to was part of the common general knowledge as at the priority date of the application.

Summary of Invention

[0007] According to a first aspect of the invention there is provided a trolley comprising a mobile frame for supporting a plurality of shelves each for receiving a load, and a support mechanism for supporting the shelves and for moving the shelves in a circulating manner such that each of the shelves is moveable to a loading/unloading position, wherein the movement of the shelves is controlled by a self-locking worm drive.

[0008] In an embodiment, the worm drive comprises a worm wheel operatively associated with a worm screw such that a leading face of the worm screw engages with a radial surface of a tooth of the worm wheel such that a drive force exerted by the leading face of the worm screw is substantially evenly distributed across a thickness of the radial surface of the tooth of the worm wheel.

[0009] In an embodiment a net load induced force, comprising a force created by a load in each of the shelves, is exerted by the radial surface of the tooth of the worm wheel on the worm screw without inducing rotation of the worm screw thereby locking the self-locking worm drive.

[0010] In an embodiment, the thickness of the radial surface of the tooth of the worm wheel is substantially parallel to an axis of rotation of the worm wheel. In an embodiment, substantially the full thickness of the radial surface is in contact with the worm screw.

[0011] In an embodiment, the worm screw is operatively associated with a drive means connected to a drive shaft. The drive means comprises a handle.

[0012] In an embodiment, the worm screw is oriented at an angle equal to a lead angle of the worm screw relative to the plane of rotation of the worm wheel, wherein the radial surface of the tooth of the worm wheel is substantially parallel and abutted to the leading face of the worm screw. The drive means may be operatively connected to the worm screw by way of a universal joint such that the drive shaft forms an acute angle to an axis of rotation of the worm screw.

[0013] In an embodiment, the handle is configured to rotate in both directions wherein the plurality of shelves can be circulated in a bi-directional manner subject to the direction of rotation of said worm screw. In an embodiment, the worm drive is self-locking in both directions.

[0014] In an embodiment, the worm screw or the worm wheel, or both, comprise a self lubricating/low friction material. The self-lubricating material may be phosphor bronze. The phosphor bronze may be 5% phosphor bronze such as AS1567 GR UNS-C51800.

[0015] In an embodiment, the leading face of the worm screw is engaged with an at least one leading face of the tooth of the worm wheel and a trailing face of the worm screw is engaged with an at least one trailing face of the tooth of the worm wheel such that the backlash in the worm wheel is minimal or eliminated. The leading face and the trailing face of the worm screw may be a helical shape.

[0016] In an embodiment, a distance in the axial direction of a void between adjacent leading and trailing faces of the worm screw is substantially the same as a distance between opposed faces of a tooth of the worm wheel such that there is negligible backlash in the worm screw.

[0017] In an embodiment, the trolley further comprises a cover, wherein the cover prevents access to each load supported by each of the plurality of shelves other than through an opening in the cover positioned at the loading/unloading position.

[0018] In an embodiment, the shelves circulate through a generally vertical orientation.

[0019] In an embodiment, the support mechanism comprises at least two circulating loops connected by a plurality of horizontal members for supporting a plurality of shelves therefrom.

[0020] In an embodiment, the loops are synchronized in their movement by the horizontal members.

[0021] In an embodiment, the worm wheel is coupled to a sprocket that drives the loops.

[0022] In an embodiment, each of the plurality of shelves are removably and rotatably associated with the plurality of horizontal members extending between the at least two circulating loops.

[0023] In an embodiment, the shelves are configured to direct their supported load to a longitudinal centre of the shelf under the influence of gravity.

[0024] In an embodiment, the trays are separable from the shelves. In an embodiment, the trays are loaded in a location away from the trolley. In an embodiment, the shelves comprise a tray supporting means for receiving a tray during loading/unloading of a tray. In an embodiment, the tray comprises one or more supports configured for facilitating handling and movement of the trays.

[0025] In an embodiment, the support mechanism is heat tolerant so that it is able to be heated in an oven. Advantageously, the phosphor bronze of the worm drive is heat tolerant. More advantageously a lubricant is not needed to be applied to the worm drive when the trolley has been or is to be in the heated oven.

[0026] According to a second aspect of the invention there is provided a method for producing a trolley comprising manufacturing a mobile frame, supporting a plurality of shelves from the mobile frame, connecting a support mechanism to support the shelves and move the shelves in a circulating manner to a loading/unloading position, and controlling the movement of the shelves with a self-locking worm drive.

[0027] In an embodiment control of the movement comprises engaging a leading face of the worm screw with the radial surface of a tooth of the worm wheel and exerting a drive force from the leading face of the worm screw substantially evenly distributed across a thickness of the radial surface of the tooth of the worm wheel.

[0028] According to a third aspect of the invention there is provided a method for moving and self-locking a plurality of movable shelves of a trolley comprising activating a drive means, the drive means driving a worm drive connected to a support mechanism, wherein the support mechanism is supported by a mobile frame of the trolley is supporting a plurality of movable shelves, moving the plurality of shelves supported by the support mechanism when the worm drive is activated, ceasing to activate the drive means and self-locking the worm drive when the drive means is ceased to be activated preventing the movement of the plurality of shelves.

Brief Description of Drawings

[0029] A preferred embodiment of the invention will now be described with reference to the following drawings, in which:

Figure 1 is an isometric view of a trolley according to an embodiment of the present invention;

Figure 2 is an isometric view of a cross-section 2-2 of the trolley of Figure 1, with a side panel of a cover removed;

Figure 3 is an isometric view of the self-locking support mechanism;

Figure 4 is an isometric view of the self-locking support mechanism with the handle arranged a different angle;

Figure 5 is an isometric view of the self-locking support mechanism engaged with a larger wheel further engaged with one of a circulating loop;

Figure 6 is a top view of the alignment of the worm screw and worm wheel of the self-locking worm drive;

Figure 7 is an isometric view of the worm wheel.

Figure 8 is a side view of a cross-section 2-2 of the trolley of Figure 1, with a side panel of a cover removed.

Description of Embodiments

[0030] Referring to Figure 1, there is shown a trolley 5 with movable shelves 12 driven by a self locking support mechanism 40 (seen in Figures 3 through 5), the trolley 5 comprising a mobile frame 10 for supporting a plurality of shelves 12, or trays, each capable of receiving a load. The plurality of shelves 12 move in a circulating manner whereby each of the shelves 12 is moveable to an opening 38 in the cover 34 of the trolley at a loading/unloading position. The movement of the shelves 12 is controlled by a self-locking worm drive 42 (shown in Figure 3). The opening 38 makes the loading/unloading position at a height which is conducive to proper manual handling practices for loading/unloading a load into/from the plurality of shelves 12.

[0031] The shelves 12, or trays, may comprise at least one hole or perforation 30 in each of the shelves 12, or trays to support ventilation and/or reduce weight. The shelves 12 are circulated in a generally vertical orientation. The shelves 12, or trays, may also be configured to direct their supported loads to a longitudinal centre of the shelve 12 under the influence of gravity. The shelves 12 may be formed in this manner or deformed manually for this purpose.

[0032] In one embodiment, each of the trays are separable from a respective shelf 12. The shelves 12 comprise a tray supporting means. Each shelf 12 may support one or more trays. A tray supporting means may include, but is not limited to, a cradle, support members, mesh, wire frame, etc. Each tray may comprise one or more supports for receiving lifting means to facilitate the handling and movement of a respective tray including for example in or in association with the cradle. In this manner the samples in the tray may be loaded into a respective tray at a separate location to prepare for loading/unloading into a respective shelf 12 of the trolley 5.

[0033] The trolley 5 further comprises forklift tine receiving pockets/tubes 90 suitable for lifting and moving by a forklift. The mobile frame 10 of the trolley 5 comprises wheels 40 for ease of moving the trolley 5 to a desired location, particularly when there is limited room for a forklift. The frame may also have one or more side panels 70 which at least provide strength, rigidity and a member to support the mounting of internal components of the trolley 5.

[0034] Figure 2 shows the trolley 5 on the mobile frame 10 with the support mechanism for supporting the plurality of shelves 12. In this embodiment, the support mechanism comprises at vertically spaced apart wheels 18, such as large sprocket wheels 181. Each side of the trolley has a pair of vertically spaced apart wheels 18. The vertically spaced apart wheels 18, or large sprocket wheels 181, are mounted on the mobile frame 10 of the trolley by stub axles 14A and 14B such that the sprocket wheels 181 are free to rotate.

[0035] The vertically spaced apart wheels 18 engage with a plurality of parallel links 22 joined at their ends to form a loop 20 for engaging and circulating the loop 20 around the two vertically spaced apart wheels 18. In another embodiment, the loop may be a belt or other material suitable for creating a loop 20 and the vertically spaced apart wheels 18 can be any wheel compatible with the chosen loop 20. Accordingly, in this embodiment, the support mechanism comprises two circulating loops. The cover 34 prevents interference with the lower most shelf 12"', the back line of shelves 12', and the upper most shelf 12" until they have circulated to the opening 38.

[0036] Figure 3 shows the self-locking support mechanism 40 which is operatively associable with the trolley 5 (seen in Figures 1 and 2) on the mobile frame 10 for supporting a plurality of shelves 12. A self-locking worm drive 42 of the support mechanism 40 is shown comprising a worm wheel 44 and worm screw 46. The self-locking worm drive 42 is supported within a housing 41 such that the worm screw 46 is oriented at an angle with respect to the worm wheel 44 as described further below in relation to Figure 4. The worm screw 46 is operable by way of a shaft 54 rotated by activation of a drive means, such as a handle 26. There is a universal joint 52 in between the worm screw 46 and the shaft 54 to account for the unaligned orientation of the worm screw 46 (due to the angle of the worm screw 46). The activation of the handle 26 (by cranking) rotates the shaft 54 and universal joint 52 causing the worm screw 46 to rotate thereby driving the worm wheel 44. The worm wheel 44 is coupled to a drive shaft 48. Drive shaft 48 further has drive sprocket 50 coupled to it. The shaft 48 is positioned to allow drive sprocket 50 to operatively engage with the sprocket wheel 181 (as seen in Figure 5). In this embodiment, drive shaft 48 extends across trolley 5 where there is another sprocket (not shown) operatively engaged with another sprocket wheel (not shown). The worm wheel 44 may also be directly coupled to a sprocket that drives the loop or loops 20.

[0037] Referring to Figure 4, the worm screw 46 is operatively associated with the drive means through drive shaft 54. The drive means may be a handle 26'. The orientation of the handle 26 may be configured in a plane that is offset but parallel to the plane with the worm wheel 46 by way of a gearbox 30 which is configured to transmit rotational force at an angle necessary to drive the worm screw 46 of the self-locking worm drive 42. The handle 26' may be operatively connected to the worm screw 46 by way of the universal joint 52 such that the rotational axis of the drive shaft 54 forms the acute angle to the axis of rotation 60 of the worm screw 46. The person skilled in the art would appreciate that the orientation of the handle 26 is adaptable to account for the structure of the trolley 5, clearance of the circulating loops 20 (seen in Figure 5), and the positioning and type of handle can be modified from those shown in Figures 3 and 4.

[0038] The handle 26 is configured to rotate in a both directions thereby allowing the plurality of shelves 12 to be circulated in a bi-directional manner subject to the direction of rotation of the worm screw 46. The drive means may be of a different form to that of a handle.

[0039] The worm wheel 44 is operatively associated with a worm screw 46 wherein the leading face of a helical thread 70 of the worm screw 46 is engaged with one or more of the radial surfaces of a tooth 72 or teeth of the worm wheel 44 such that the worm screw 46 can exert a drive force that is substantially evenly distributed across a thickness of the radial surface 74 of the tooth 72 or teeth of the worm wheel 46.

[0040] Thus when the worm screw 46 is rotated by the shaft 54 the thread 70 rotates and applies a force to a face of one or more of the teeth 72 of the worm wheel 46 causing it to move within a helical groove 74 of the worm screw 46, thereby rotating the worm wheel 44. Rotation of the worm screw 46 in the opposite direction applies a force to the opposite face of the tooth 72 of the worm wheel 44 causing the worm wheel 44 to rotate in the opposite direction. The worm wheel 44 is affixed to a drive shaft 48 which further comprises a drive sprocket 50 which is operatively engaged with the upper wheel of the vertically spaced apart wheels 18 to drive the larger sprocket wheel 181 when the worm wheel 44 is rotated and thereby circulating the loop 20 shown in Figure 5.

[0041] In this embodiment, the drive shaft 48 extends horizontally across the trolley 5 to drive the upper wheel of the pair of vertically spaced apart wheels 18 located on the opposite side of the trolley 5. Furthermore, there are a plurality of horizontal support members 24 wherein each end is attached to one of the loops 20, respectively. The horizontal members 24 and horizontal drive shaft 54 support, and may assist in synchronising the circulation of the shelves 12.

[0042] The shelves 12 are rotatably and removably associated with the plurality of horizontal members 24 which extend between the circulating loops 20. As the shelves 12, which in this embodiment are hung from the horizontal support members 24, are loaded with a sample in each of the plurality of shelves 12 a net load induced force is created, comprising a weight created by a load in each of the shelves 12. The net load induce force is exerted through the large sprocket wheel 181 to the drive sprocket 50 and thereon to the worm wheel 44. The radial surface of the tooth of the worm wheel 44 thereby transmits this net load induced force to the worm screw 46. As the force exerted by the radial surface of the tooth or teeth of the worm wheel 44 is exerted is substantially perpendicular to the face of the worm screw 46, the worm screw 46 is not induced to rotate thereby locking the self-locking worm drive 42.

[0043] Referring to Figure 6, there is a top view of the self-locking worm drive 42 and more specifically shows the alignment of the worm wheel 44 and the worm screw 46. The axis of rotation

60 of the worm screw 46 is oriented at an angle to the axis of rotation 58 of the worm wheel 44. As such, where a force exerted by a weight of a load in the plurality of shelves 12 exerts a force through the drive sprocket 50. The drive sprocket 50 in turn applies a force which induces the rotation of the worm wheel 44. The angle of the axis of rotation 60 of the worm screw 46 is such that when the load force exerted by the worm wheel 44 to the thread 70 of the worm screw 46, the load force is applied by a thickness of the tooth 72 that is substantially parallel with the face of the thread 70 of the worm screw 46. This load force is applied substantially perpendicular to the face of the thread 70 of the worm screw 46 such that it does not induce rotation of the worm screw 46. Where there is no rotation of the worm screw 46 the worm drive 42 is effectively self locked, preventing the shelves 12 from circulating. Accordingly, when the handle 26 is not activated, the circulating plurality of shelves 12 are locked into place by the configuration of the worm drive 42. This can occur in both directions, depending on whether the weight of the load is more on the front or back of the trolley 5.

[0044] Due to the axis of rotation 60 being orientated at an angle, the driving face of the worm screw 46 engages substantially parallel with the radial surfaces of the teeth of the worm wheel 44. In one embodiment, the worm screw 46 is oriented at an anglee substantially equal to a lead angle of the worm screw 46 relative to the plane of rotation of the worm wheel 44, wherein the radial surface of the tooth of the worm wheel 44 is substantially parallel and abutted to the leading face of the worm screw 46. As the face of the teeth of the worm wheel 44 are engaging with a parallel surface of the leading edge of the worm screw 46, the worm wheel 44 can be sourced as a basic gear with radial surfaces parallel to the axis of rotation 58, such as a simple spur gear.

[0045] Referring to Figure 7, there is provided aside view of the trolley 5 with the pair of vertically spaced apart wheels 18, the upper wheel being a larger sprocket wheel 181. The loop 20 comprises a number of individual pairs of parallel links 22 joined at their respective ends such that the loop 20 is engageable with the vertically spaced apart wheels 181. The loop 20 is engaged with the vertically spaced apart wheels 18 wherein the loop 20 has a plurality of horizontal support members 24 extending horizontally across the trolley 5. The shelves 12 hang from the plurality of horizontal support members 24 by one or more hooks 28 spaced longitudinally across the length of the shelves 12. The shelves 12 have a flattened back lip or wall 25 as a guide and to assist in preventing or reducing swaying of the shelves 12 as they circulate into the back line of shelves 12'. There may also be guide members 92 for guiding the flattened back lip or wall 25 of the shelves 12 to prevent or reduce the front line of shelves 12 from swaying.

[0046] The drive sprocket 50 may be directly engaged with the upper wheel of the vertically spaced apart wheels 181 (as seen in Figure 5). Alternatively, for purposes of gear reduction there may be one or more intermediate wheels or gears 184 to alter the manner of circulation of the shelves 12. Intermediate gears 184 can be mounted on side panels 70 (seen in Figure 1) on a stub axle similar to 14A or 14B.

[0047] The worm screw 46 or the worm wheel 44, or both, may comprise a self-lubricating material. The self-lubricating/low friction material may be phosphor bronze. The person skilled in the art will appreciate that other non-self-lubricating/low friction materials may be used the self locking worm drive 42 is capable of having a mesh between the worm screw 46 and the worm wheel 44 is suitable for having no substantial backlash without sticking, such as by galling, of the worm wheel 44 and worm screw 46 or excessive wear therebetween. Preferably the phosphor bronze is 5% phosphor bronze such as AS1567 GR UNS-C51800, however, other grades having one or more similar properties may be suitable.

[0048] In an embodiment, the leading face of the worm screw 46 is engaged with an at least one leading face of the tooth 72 of the worm wheel 44 and an a trailing face of the thread 70 of the worm screw 46 is engaged with an at least one trailing face of the tooth 72 of the worm wheel 44 such that the backlash in the worm wheel 44 is minimal or eliminated. The leading face and the trailing face of the worm screw 46 may be a helical shape having a spacing that is substantially the same as the size of the tooth 72 of the worm wheel 44 to be received in the groove 74 formed therebetween.

[0049] In an embodiment, the support mechanism and all components of the trolley 5 are heat tolerant so that it is able to be heated in an oven. Advantageously, the phosphor bronze of the worm drive is heat tolerant. More advantageously a lubricant is not needed to be applied to the worm drive when the trolley has been in or is to be placed in the heated oven.

[0050] The method of operation of the present invention will now be described with reference to the accompanying figures.

[0051] The trolley 5 is able to be loaded with an item, such as a core sample by placing it on the shelf 12 aligned with the opening 38. The crank handle 26 can be rotated in either direction. This will cause the worm screw 46 to turn, which in turn advances the at least two loops 20 and moves the shelves 12 so that the next tray 12 becomes aligned with the opening 38. Once cranking the handle stops 26, the load in one or more of the plurality of shelves 12 will exert a substantially perpendicular force onto the face of the worm screw 46 which is does not induce the worm screw 46 to rotate thereby locking the worm drive 42 and holding the at least two loops 20 in position, so that the next item can be loaded in the next tray 12.

[0052] This process can continue until all of the shelves 12 are full. In doing so, the shelves 12 can rotate about the horizontal bars 24 so as to remain correctly oriented under the influence of gravity, particularly as they pass from the front line to being the bottom tray 12"', upward as the back line of trays 12' and as they pass to being the top tray 12" back to the front line again. The shelves may be formed such that a load under the influence of gravity will move toward the longitudinal centre of the tray.

[0053] The trolley 5 can then be moved, such as into a heated oven to dry the core samples.

[0054] The trolley 5 can also be easily unloaded by taking the item from the shelf 12 aligned with the opening 38. Again, cranking the handle 26 will advance the shelves 12 so that the items can be removed as each tray 12 becomes aligned with the opening 38.

[0055] 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.

[0056] Throughout the specification unless the context requires otherwise, the word "include" or variations such as "includes" or "including", 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.

[0057] Modifications may be made to the present invention within the context of that described and shown in the drawings. Such modifications are intended to form part of the invention described in this specification.

Claims

The Claims Defining the Invention are as Follows

1. A trolley comprising:

a mobile frame for supporting a plurality of shelves each for receiving a load, and

a support mechanism for supporting the shelves and for moving the shelves in a circulating manner such that each of the shelves is moveable to a loading/unloading position,

wherein the movement of the shelves is controlled by a self-locking worm drive, wherein the worm drive comprises a worm wheel operatively associated with a worm screw such that a leading face of the worm screw engages with a radial surface of a tooth of the worm wheel such that a drive force exerted by the leading face of the worm screw is substantially evenly distributed across a thickness of the radial surface of the tooth of the worm wheel, wherein the worm screw is operatively associated with a drive means connected to a drive shaft, wherein the drive means comprises a handle configured to rotate in both directions wherein the plurality of shelves can be circulated in a bi-directional manner subject to the direction of rotation of said worm screw, and wherein the worm screw is oriented at an angle equal to a lead angle of the worm screw relative to the plane of rotation of the worm wheel, wherein the radial surface of the tooth of the worm wheel is substantially parallel and abutted to the leading face of the worm screw..

2. A trolley according to claim 1, wherein a net load induced force, comprising a force created by a load in each of the shelves, is exerted by the radial surface of the tooth of the worm wheel on the worm screw without inducing rotation of the worm screw thereby locking the self-locking worm drive.

3. A trolley according to claim 2, wherein the thickness of the radial surface of the tooth of the worm wheel is substantially parallel to an axis of rotation of the worm wheel.

4. A trolley according to claim 2 or 3, wherein substantially the full thickness of the radial surface is in contact with the worm screw.

5. A trolley according to any one of claims 1 to 4, wherein drive means is operatively connected to the worm screw by way of a universal joint such that the drive shaft forms an acute angle to an axis of rotation of the worm screw.

6. A trolley according to any one of claims 1 to 5, wherein the worm screw and/or the worm wheel comprise a self-lubricating/low friction material.

7. A trolley according to claim 6, wherein the self-lubricating/low friction material comprises a phosphor bronze.

8. A trolley according to any one of claims 1 to 7, wherein the leading face of the worm screw is engaged with an at least one leading face of the tooth of the worm wheel and a trailing face of the worm screw is engaged with an at least one trailing face of the tooth of the worm wheel such that the backlash in the worm wheel is minimal or eliminated.

9. A trolley according to any one of claims 1 to 8, wherein the trolley further comprises a cover, wherein the cover prevents access to each load supported by each of the plurality of shelves other than through an opening in the cover positioned at the loading/unloading position.

10. A trolley according to any one of claims 1 to 9, wherein the support mechanism is heat tolerant.

11. A trolley comprising:

a support mechanism for supporting the shelves and for moving the shelves in a circulating manner such that each of the shelves is moveable to a loading/unloading position, wherein the movement of the shelves is controlled by a self-locking worm drive, wherein a net load induced force, comprising a force created by a load in each of the shelves, is exerted by a radial surface of a tooth of a worm wheel on a worm screw without inducing rotation of the worm screw thereby locking the self-locking worm drive.

12. A method for producing a trolley comprising the steps:

manufacturing a mobile frame,

supporting a plurality of shelves from the mobile frame,

connecting a support mechanism to support the shelves and move the shelves in a circulating manner to a loading/unloading position,

and controlling the movement of the shelves with a self-locking worm drive, wherein the self-locking worm drive is configured such that, when a net load induced force, comprising a force created by a load in each of the shelves, is exerted by a radial surface of a tooth of a worm wheel on a worm screw without inducing rotation of the worm screw thereby locking the self-locking worm drive.

13. A method for moving and self-locking a plurality of movable shelves of a trolley, the method comprising the steps:

activating a drive means, the drive means driving a worm drive connected to a support mechanism,

wherein the support mechanism supported by a mobile frame of the trolley is supporting a plurality of movable shelves,

moving the plurality of shelves supported by the support mechanism when the worm drive is activated,

ceasing to activate the drive means and self-locking the worm drive when the drive means is ceased to be activated preventing the movement of the plurality of shelves wherein the worm drive is configured such that, when a net load induced force, comprising a force created by a load in each of the shelves, is exerted by a radial surface of a tooth of a worm wheel on a worm screw without inducing rotation of the worm screw thereby locking the worm drive.

- 1/6 - 14 Oct 2021

2-2 2021250936

10 5

12

24

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30 34

70

40

90

FIGURE 1

- 2/6 - 14 Oct 2021

12’’

18 12 2021250936

14A

20 184

24 50 12’ 12 92

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14B

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FIGURE 2

- 3/6 - 14 Oct 2021

40 50

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18

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FIGURE 5

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58 70 46

44 2021250936

θ

60

74 72

FIGURE 6

72

FIGURE 7

- 6/6 - 14 Oct 2021

18

181 14A

12 2021250936

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178

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20

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FIGURE 8