GB2613951A

GB2613951A - Drive assembly

Info

Publication number: GB2613951A
Application number: GB2216285.3A
Authority: GB
Inventors: Gittins John
Original assignee: Allett Ltd
Current assignee: Allett Ltd
Priority date: 2021-11-02
Filing date: 2022-11-02
Publication date: 2023-06-21
Anticipated expiration: 2042-11-02
Also published as: GB2613951B; GB202216285D0; GB202115758D0

Abstract

A drive assembly 100 comprising a drive member 1, a roller 3 and a freewheel 2. The freewheel switches between a locked (fig.9) and unlocked (fig.11) configuration. The freewheel transmits torque from the drive member to the roller in the locked configuration and allow the roller to rotate freely in the unlocked configuration. The unlocked configuration is achieved by rotating the roller relative to the drive member and the locked configuration is achieved by rotating the drive member relative to the roller. The freewheel may comprise a hub (fig.2, 27), fixing elements (fig.6, 271), a cam (fig.2, 26) rotatably fixed to a drive shaft 1, a housing (fig.2, 25) and rolling elements (fig.2, 28) between fixing elements, extending between clutch and housing surfaces, contact the surfaces in the locked configuration such that the housing drives the roller. A switch gear may drive the hub using a friction fit.

Description

DRIVE ASSEMBLY

TECHNICAL FIELD

The present invention relates to a drive assembly for a mower and a mower comprising the drive assembly.

BACKGROUND

A self-propelled mower typically comprises one or more traction elements to propel the mower along the ground in use and one or more cutting elements for cutting grass.

Self-propelled mowers include walk-behind mowers, which typically comprise a handle which a user holds as they walk behind the mower in use. Self-propelled mowers include rotary mowers and cylinder mowers. A rotary mower typically comprises traction elements in the form of a plurality of wheels and a cutting element in the form of a rotary blade configured to rotate about a vertical axis in use. A cylinder mower typically comprises traction elements in the form of one or more rollers and a cutting element in the form of a cylinder blade configured to rotate about a horizontal axis in use.

A cylinder mower is used to create the 'striped' lawn effect typically seen, for example, in a sports environment, such as on a football pitch or tennis court. The roller, as well as propelling the mower along the ground, flattens the cut grass such that the blades of grass in a strip of grass are aligned in a single direction. A rotary mower would not be suitable for this application The one or more traction elements of a walk-behind self-propelled mower are typically configured to propel the mower in a forward direction only. To change the direction of travel of the mower, a user is required to manually manoeuvre the mower. This often requires having to pull the mower backwards. This requires having to overcome the inertia of the drive train of the mower, which often requires significant physical effort. In addition, the traction of the wheels or roller of a mower on grass may not be sufficient to overcome the braking effect of the drive train, thereby causing the wheels or rollers to slide and potentially damage the grass.

Known solutions require the user to first switch off a power source, such as an internal combustion engine or an electric motor, configured to drive the one or more traction elements and then manually disengage the drive train. For example, where drive is transmitted from the power source to the one or more traction elements via a belt and pulley system, a user may be required to manually release the tension in the belt to disengage the drive train.

SUMMARY

A first aspect of the invention provides a drive assembly for a mower. The drive assembly comprises a drive member, a roller, and a freewheel mechanism. The freewheel mechanism is switchable between a locked configuration and an unlocked configuration. The freewheel mechanism is configured to transmit torque from the drive member to the roller in the locked configuration and allow the roller to rotate freely relative to the drive member in the unlocked configuration. The freewheel mechanism is switchablc from the locked configuration to the unlocked configuration by rotating the roller relative to the drive member and switchable from the unlocked IS configuration to the locked configuration be rotating the drive member relative to the roller.

In use, the drive assembly may form part of a drive train of a walk-behind self-propelled cylinder mower. The drive member may be configured to transmit torque from a power source of the mower to the roller via the freewheel mechanism. in the unlocked configuration, the freewheel mechanism allows the roller to rotate freely relative to drive member in a first direction and a second direction, opposite the first direction. This enables a user of the mower to manually push the mower forwards or pull the mower backwards without having to overcome the inertia of the drive train and may prevent damage to grass through sliding of the roller.

A user is able to switch the freewheel mechanism from the locked configuration to the unlocked configuration by initially manually, pushing or pulling the mower, causing the roller to rotate relative to the drive member and switch the freewheel mechanism to the unlocked configuration. The freewheel mechanism can be switched from the unlocked configuration to the locked configuration by engaging the power source, causing the drive member to rotate relative to the roller and switch the freewheel mechanism to the locked configuration. The user is not required to carry out any additional actions to switch the freewheel mechanism between the locked and unlocked configurations.

The freewheel mechanism may be switchable between a first locked configuration, the unlocked configuration, and a second locked configuration. The freewheel mechanism may be configured to transmit torque in a first direction from the drive member to the roller in the first locked configuration. The freewheel mechanism may be configured to transmit torque in a second direction from the drive member to the roller in the second locked configuration. The second direction may be opposite the first direction.

The freewheel mechanism may be switchable from the first locked configuration to the unlocked configuration by rotating the roller in the second direction. The freewheel mechanism may be switchable from the second locked configuration to the unlocked configuration by rotating the roller in the first direction. The freewheel mechanism may be switchable from either the first locked configuration or the second locked configuration by rotating the roller in the first direction or the second direction. I5

The drive member may comprise a drive shaft. The drive shaft may comprise a stub shaft. In other embodiments, the drive member may comprise a drive gear. The freewheel mechanism may comprise: a cam; a clutch hub; a plurality of rolling elements; a clutch housing; a drive gear a roller drive gear; a switch gear; and/or a roller ring gear.

The cam may be rotatably fixed to the drive shaft. The clutch hub may comprise a plurality of fixed elements which may be configured to surround and receive the cam. The fixed elements may define a plurality of spaces therebetween. The clutch housing may be configured to receive the clutch hub. The plurality of rolling elements may be configured to be received within the spaces between the fixed elements of the clutch hub to extend between a drive surface of the cam and a circumferential internal surface of the clutch housing. The drive gear may be configured to be driven by the clutch housing. The roller drive gear may be configured to be driven by the drive gear.

The roller drive gear may be configured to drive the roller. The switch gear may be configured to drive the clutch hub. The roller ring gear may be configured to be driven by the roller. The roller ring gear may be configured to drive the switch gear.

The roller ring gear may be attached to the roller. The roller ring gear may be a plastic ring gear. The roller ring gear may be an injection-moulded ring gear. The roller ring gear may comprise a unitary part. The roller drive gear may be attached to the roller ring gear. The roller ring gear may comprise mounting features for attaching the roller drive gear to the roller ring gear. The roller ring gear may comprise a hub. The hub may comprise mounting features for attaching the roller drive gear to the roller ring gear.

The plurality of rolling elements may be configured to adopt a locked position when the freewheel mechanism is in the locked configuration. The plurality of rolling elements may be configured to adopt an unlocked position when the freewheel mechanism is in the unlocked configuration. The rolling elements may contact the drive surface of the cam and the circumferential internal surface of the clutch housing when in the locked position to transfer drive between the cam and the dutch housing. The rolling elements may be spaced apart from one or both of the drive surface of the cam and the circumferential internal surface of the clutch housing when in the unlocked position to allow the dutch housing to rotate freely relative to the cam. The clutch hub may be configured to be rotated by the drive shaft relative to the cam to cause the fixed elements to move the rolling elements to adopt the unlocked position from the locked position. The cam may be configured to be rotated by the drive shaft relative to the clutch hub to cause the rolling elements to adopt locked position from the unlocked position.

The freewheel mechanism comprises a friction member and a spring. The friction member and the spring may be configured to provide a friction fit between the clutch hub and the switch gear. A friction fit may allow for easy replacement of the switch gear during servicing without the need to also replace the clutch hub which may not need replacing. For example, replacement of the switch gear would also require replacement of the dutch hub if the switch gear and dutch hub were provided as a single part.

The switch gear may bc plastic. This advantageously reduces the weight of thc drive assembly compared to if the switch gear was metal, for example. The inventors have found that a plastic gear is capable of withstanding the loads required of the switch gear and so a heavier metal gear, for example, is not required.

The roller may comprise a comprises a first section and a second section. The drive assembly may comprise a differential. The differential may be configured to allow the first section and the second section to rotate at different speeds.

The drive assembly may comprise a pulley assembly configured to transmit torque from a power source to the drive member. The pulley assembly may comprise a drive pulley, a driven pulley, and a belt configured to transmit torque from the driven pulley to the drive pulley. The driven pulley may be configured to transmit torque from the belt to the drive member.

The belt may be a fixed tension belt. The pulley assembly may not comprise any means to selectively release tension in the belt.

The drive assembly may remove the need for means to manually release tension in the belt, such as a belt clutch. Belt clutches typically require frequent maintenance and adjustment. They can also be unreliable; for example, they can slip. The drive assembly of the present invention may remove the need for a belt clutch, thereby reducing the overall maintenance requirements and improving the overall reliability of a mower comprising the drive assembly.

Although the drive assembly of the first aspect of the invention is particularly suited to mowers, it will be appreciated that it is also applicable to any suitable self-propelled machinery or equipment comprising a roller. For example, the invention is also applicable to self-propelled turf rollers which do not necessarily comprise a cutting element.

A second aspect of the invention provides a mower comprising the drive assembly of the first aspect of the invention. The mower may comprise a cylinder blade. The mower may comprise a walk-behind self-propelled cylinder mower.

The mower may comprise a first motor configured to deliver torque to the drive member and a second motor configured to deliver torque to the cylinder blade.

A third aspect of the invention provides an item of equipment comprising the drive assembly of the first aspect of the invention. The item of equipment may be any suitable item which utilises a roller, such as a self-propelled turf roller which does not necessarily comprise a cutting clement.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings: Figure 1 shows a schematic isometric view of a drive assembly for a mower according to an embodiment of the invention; Figure 2 shows a schematic isometric view of components of a freewheel mechanism of the drive assembly of Figure 1; Figure 3 shows a schematic isometric view of a drive gear and a clutch housing of the freewheel mechanism; Figure 4 shows a schematic front view of a projection of the clutch housing received IS within a bore of the drive gear; Figure 5 shows a further schematic isometric view of the clutch housing; Figure 6 shows a schematic isometric view of the clutch housing, and a cam, a clutch hub, and rolling elements of the freewheel mechanism; Figure 7 shows a schematic isometric view of the clutch hub, and a switch gear, a friction member, and a spring of the freewheel mechanism; Figure 8 shows a schematic front view of the clutch hub relative to the clutch housing, the drive gear and a drive shaft of the freewheel mechanism when the drive assembly is assembled; Figure 9 shows a schematic front view of components of the freewheel mechanism with the freewheel mechanism in a locked configuration; Figure 10 shows the torque flow through a portion of the drive assembly when the freewheel mechanism is in the locked configuration; Figure 11 shows a schematic front view of components of the freewheel mechanism with the freewheel mechanism in an unlocked configuration; Figure 12 shows a schematic isometric view of the drive assembly with a first section of a roller of the drive assembly removed; Figure 13 shows a schematic close-up view of a differential of the drive assembly; Figure 14 shows a schematic isometric view of a mower comprising the drive assembly; Figure 15 shows a schematic dose-up view of the mower in which various components of the drive assembly are visible; and Figure 16 shows a schematic close-up view of the mower with a fairing panel removed.

DETAILED DESCRIPTION

Figure 1 shows a schematic isometric view of a drive assembly 100 for a mower according to an embodiment of the invention. The drive assembly 100 comprises a drive member 1, a roller 3, and a freewheel mechanism 2. In this embodiment, the drive member 1 comprises a drive shaft configured to be driven by a power source such as an electric motor or an internal combustion engine. The freewheel mechanism 2 is switchable between a locked configuration and an unlocked configuration. The freewheel mechanism 2 is configured to transmit torque from thc drive shaft 1 to the roller 3 in the locked configuration and allow the roller 3 to rotate freely relative to the drive shaft 1 in the unlocked configuration. The freewheel mechanism 2 is switchable from the locked configuration to the unlocked configuration by rotating the roller 3 relative to the drive shaft 1 and switchablc from the unlocked configuration to the locked configuration be rotating the drive shaft 1 relative to the roller 3.

in this embodiment, the roller 3 comprises a first section 31 and a second section 32, described in further detail below. In other embodiments, the roller 3 may comprise a single section.

The freewheel mechanism 2 comprises a drive gear 21, a switch gear 22, a roller ring gear 23, and a roller drive gear 24. The drive gear 21 and the switch gear 22 are arranged coaxially with the drive shaft 1. The drive shaft 1 comprises a stub shaft configured to be driven at an end thereof distal from the drive gear 21. The drive gear 21 is configured to drive the roller drive gear 24 and the roller drive gear 24 is configured to drive the roller 3 via a central axle. The roller ring gear 23 is configured to drive the switch gear 22.

The roller ring gear 23 is attached to the first section 31 of the roller 3 for rotation with the first section 31 of the roller 3. In this embodiment, the roller ring gear 23 comprises a single unitary injection moulded plastic part. The roller ring gear 23 comprises a plurality of attachment features 231 for attaching the roller ring gear 23 to the roller 3. The roller ring gear 23 further comprises a hub 232 comprising a plurality of mounting features (not shown) for mounting the roller drive gear 24 to the roller ring gear 23 for rotation with the roller ring gear 23. In this embodiment, the roller drive gear 24 comprises a metal part.

Figure 2 shows a schematic isometric view of components of the freewheel mechanism 2. The freewheel mechanism 2 further comprises a clutch housing 25, a cam 26, a clutch hub 27, a plurality of rolling elements 28, a friction member 29, a spring 210, a plurality of washers 211, and a retaining clip 212. When the drive assembly 100 is assembled, each of the components shown in Figure 2 are arranged coaxially about the drive shaft 1. The washers 211 and retaining clip 212 are arranged on an end of the drive shaft 1 to retain the components in position.

Figure 3 shows a schematic isometric view of the drive gear 21 and the clutch housing 25. The clutch housing 25 comprises a housing portion 251 and a projection 252 extending from the housing portion 251. The clutch housing 25 comprises a central longitudinal bore extending through the housing portion 251 and the projection 252. When the drive assembly 100 is assembled, the drive shaft 1 extends through the longitudinal bore of the clutch housing 25 and the clutch housing 25 is free to rotate relative to the drive shaft 1. The clutch housing 25 may be mounted to the drive shaft 1 via a suitable bearing to allow the clutch housing 25 to rotate freely about the drive shaft 1. The drive gear 211 comprises a central bore 211 configured to receive the projection 252 of the dutch housing 25.

Figure 4 shows a schematic front view of the projection 252 received within the bore 211 of the drive gear 21. The bore 211 and the projection 252 are shaped such that when the projection 252 is received within the bore 211, an initial rotation of the clutch housing 25 can cause the projection 252 to rotate within the bore 211 without any transmission of torque from the clutch housing 25 to the drive gear 21. Following the initial rotation, an external surface of the projection 252 will come into contact with an internal surface of the bore 211. Further rotation of the clutch housing 25 in the same direction will then cause the drive gear 211 to rotate with the clutch housing 25.

Figure 5 shows a further schematic isometric view of the clutch housing 25. The housing portion 251 comprises a circumferential internal surface 2511 defining an internal volume 2512 Figure 6 shows a schematic isometric view of the clutch housing 25, the cam 26, the clutch hub 27, and the rolling elements 28. When the drive assembly 100 is assembled, the cam 26 is rotatably fixed to the drive shaft 1, such that the cam 26 rotates with the drive shaft I. The clutch hub 27 comprises a plurality of fixed elements 271 which are configured to surround and receive the cam 26. The fixed elements 271 define a plurality of spaces therebetween and the rolling elements 28 are configured to be received within the spaces, as shown in Figure 6. Embodiments of the invention may comprise any suitable number of fixed and rolling elements. The internal volume 2512 of the housing portion 251 of the clutch housing 25 is configured to receive the clutch hub 27 and the cam 26, with the rolling elements 28 received within the spaces between the fixed elements 271 of the clutch hub 27 and extending between the cam 26 and the circumferential internal surface 2511 of the clutch housing 25.

Figure 7 shows a schematic isometric view of the switch gear 22, the clutch hub 27, the friction member 29, and the spring 210. The clutch hub 27 comprises a tubular projection 272 extending from an axial surface of the clutch hub 27. The friction member 29 is arranged on the axial surface. The switch gear 22 comprises an axial inner surface 221 and a central bore 222. When the drive assembly 100 is assembled, the tubular projection 272 is received within the central bore 222 of the switch gear 22 and the spring 210 is received on the tubular projection 210, arranged between the axial surface of the clutch hub 27 and the axial inner surface 221 of the switch gear 22.

Figure 8 shows a schematic front view of the clutch hub 27 relative to the clutch housing 25, the drive gear 21 and the drive shaft 1 when the drive assembly 100 is assembled. The tubular projection 272 of the clutch hub 27 comprises a central longitudinal bore 2721 configured to receive a portion of the drive shaft I. The bore 2721 and the portion of the drive shaft 1 are shaped such that an initial rotation of the shaft 1 within the bore 2721 can be allowed before any torque is transmitted from the drive shaft 1 to the clutch hub 27, and an initial rotation of the clutch hub 27 relative to the drive shaft 1 is allowed before any resistive torque is transmitted from the drive shaft 1 to the clutch hub 27. Following an initial rotation of the drive shaft 1 within the bore 2721, an external surface of the shaft 1 will come into contact with an internal surface of the bore 2721. Further rotation of the shaft 1 in the same direction will then cause the clutch hub 27 to rotate with the shaft 1.

Referring back to Figure 7, when the switch gear 22 and the dutch hub 27 are stationary, the spring 210 urges the axial inner surface 221 of the switch gear 22 into contact with the friction member 29, providing a friction fit between the switch gear 22 and the clutch hub 27. When the switch gear 22 is rotated from a stationary position, the friction fit means that the switch gear 22 transmits torque to the clutch hub 27. This may cause an initial movement of the clutch hub 27 relative to the drive shaft 1, as described with reference to Figure 8. Following the initial movement, the drive shaft 1 will transmit a resistive torque to the clutch hub 27. This resistive torque will be transmitted to the switch gear 22 due to the friction fit between the switch gear 22 and the clutch hub 27 provided by the friction member 29 and the spring 210. The friction member 29 and the spring 210 are configured such that if a torque applied to the switch gear 22 is greater than the resistive torque of the drive shaft 1 on the clutch hub 27, the torque applied to the switch gear 22 will overcome the friction fit and the switch gear 22 will rotate relative to the clutch hub 27, In this embodiment, the freewheel mechanism 2 is switchable between a first locked configuration, the unlocked configuration, and a second locked configuration. Figure 9 shows a schematic front view of components of the freewheel mechanism 2 with the freewheel mechanism 2 in the first locked configuration. The cam 26 comprises a plurality of drive surfaces 261, with each rolling element 28 arranged between the circumferential internal surface 2511 of the clutch housing 25 and one of the drive surfaces 261 when the freewheel mechanism 2 is assembled. In the first and second locked configurations, the rolling elements 28 adopt a locked position in which the rolling elements 28 contact the drive surface 261 of the cam 26 and the circumferential internal surface 2511 of the clutch housing 25 (see Figures 5 and 6). In this position, the rolling elements 28 are essentially wedged between the drive surface 261 of the cam 26 and the circumferential internal surface 2511 of the clutch housing 25. This causes the clutch housing 25 to rotate with the cam 26 when the cam 26 is rotated by the drive shaft 1. Rotation of the clutch housing 25 then drives rotation of the drive gear 21, which in turn drives rotation of the roller 3 via the roller drive gear 24.

In the first locked configuration, each rolling element 28 contacts the respective drive surface 261 of the cam 26 at a point to the left of the centre of the drive surface 261 as shown in Figure 9. When torque is applied to the drive shaft 1 in the direction of the arrow shown in Figure 9, with the freewheel mechanism 2 in the first locked configuration, this torque is transmitted to the clutch housing 25. In the second locked configuration, each rolling element 28 contacts the respective drive surface 261 of the cam 26 at a point to the right of the centre of the drive surface 261 as shown in Figure 9. When torque is applied to the drive shaft 1 in the opposite direction of the arrow shown in Figure 9, with the freewheel mechanism 2 in the second locked configuration, this torque is transmitted to the clutch housing 25. In use, this allows the roller 3 to be driven in a clockwise or ant clockwise direction, thereby moving a I5 mower comprising the roller 3 in a forwards or reverse direction.

Figure 10 shows the torque flow through a portion of the drive assembly 100 when the freewheel mechanism 2 is in the first or second locked configuration. The direction of torque flow is indicated by the arrows. The drive shaft 1 is driven by an external power source, such as an electric motor or an internal combustion engine. The drive shaft 1 drives rotation of the cam 26, the cam 26 drives rotation of the clutch hub 27, the dutch hub 27 drives rotation of the clutch housing 25, and the clutch housing 25 drives rotation of the drive gear 21.

Figure II shows a schematic front view of components of the freewheel mechanism 2 with the freewheel mechanism 2 in the unlocked configuration. In the unlocked configuration, the rolling elements 28 adopt an unlocked position in which the rolling elements 28 are spaced apart from one or both of the respective drive surface 261 of the cam 26 and the circumferential internal surface 2511 of the clutch housing 25, depending on the position of a particular rolling clement 28 during rotation of the cam 26 and the clutch hub 27. For example, with the cam 26 and the clutch hub 27 in a stationary position, a rolling element 28 at the bottom of the clutch housing 25, with respect to the direction of gravity, will rest on the internal surface 2511 of the clutch housing 25 and will be spaced apart from the drive surface 261 of the cam 26. A rolling element 28 at the top of the clutch housing 25 will rest on the drive surface 261 of the cam 26 and will be spaced apart from the internal surface 251! of the clutch housing 25. The rolling elements 28 are aligned with a centre point of the respective drive surface 261, as shown in Figure 11. In the unlocked configuration, the cam 26 and the clutch hub 27 are able to rotate freely within the clutch housing 25.

To switch the freewheel mechanism 2 from the first or second locked configuration to the unlocked configuration, with the components of the drive assembly 100 in a stationary position, an initial rotation of the roller 3 is performed. This drives the switch gear 22 to rotate, via the roller ring gear 23, which in turn drives the clutch hub 27 to rotate relative to the drive shaft 1 and the cam 26. As described above, the central longitudinal bore 2721 of the tubular projection 272 of the clutch hub 27 and the portion of the drive shaft I received by the longitudinal bore 2721 are shaped to allow an initial rotation of the clutch hub 27 relative to the drive shaft 1 (sec Figure 8). At the same time, the roller drive gear 24 drives the drive gear 21 to rotate in the IS opposite direction to the switch gear 22. As described above, the dutch housing 25 is free to rotate relative to the drive shaft 1. The drive gear 21 therefore drives the clutch housing 25 to rotate relative to the drive shaft 1.

The rotation of the clutch hub 27 causes the fixed elements 271 of the clutch hub 27 to push the rolling elements 2/1 into the unlocked position. Further rotation of the roller 3 will drive the switch gear 22 to overcome the friction coupling between the switch gear 22 and the dutch hub 27, allowing the switch gear 22, and therefore the roller 3, to rotate freely relative to the clutch hub 27 and the drive shaft I. As described above, the clutch housing 25 is free to rotate relative to the drive shaft 1. Further rotation of the roller 3 will therefore also drive the drive gear 21 and the clutch housing 25 to rotate freely relative to the drive shaft 1.

It will be appreciated that the direction of the initial rotation of the roller 3 required to switch the freewheel mechanism 2 from the first or second locked configuration to the unlocked configuration will be the opposite direction to that in which the roller 3 is driven to rotate when torque is transmitted from the drive shaft 1 in the respective locked configuration. For example, referring to Figure 9 with the freewheel mechanism 2 in the first locked configuration, clockwise rotation of the drive shaft 1 will cause clockwise rotation of the drive gear 21 as viewed in Figure 9. Due to the arrangement of the drive gear 21 and the roller drive gear 24 (see Figure 1), this will cause an anti-clockwise rotation of the roller 3 as viewed in the same direction as Figure 9. With the components of the drive assembly 100 in a stationary position, clockwise rotation of the roller 3 will cause a clockwise rotation of the switch gear 22 due to the arrangement of the roller ring gear 23 and the switch gear 22 (see Figure 1).

This in turn will cause a clockwise rotation of the clutch hub 27, which will cause the fixed elements 271 to push the roller elements 28 to the right, as viewed in Figure 9, towards the centre of the respective drive surface 261 of the cam 26 and into the unlocked position.

In other embodiments, the freewheel mechanism 2 may be configured such that an initial rotation of the roller 3 in either direction when the components of the drive assembly 100 are in a stationary position and the freewheel mechanism 2 is in either the first or second locked configuration, will switch the freewheel mechanism 2 to the unlocked configuration.

To switch the freewheel mechanism 2 from the unlocked configuration to the locked configuration, with the components of the drive assembly 100 in a stationary position, an initial rotation of the drive shaft 1 is performed. This causes the cam 26 to rotate relative to the clutch hub 27, the rolling elements 28 and the clutch housing 25. The cam 26 will rotate to a position at which the rolling elements 28 are in the locked position Figure 12 shows a schematic isometric view of the drive assembly 100 with the first section of the roller 3 removed. The roller 3 further comprises a drive hub 33 which is rotationally fixed to the roller drive gear 24, such that the drive hub 33 rotates with the roller drive gear 24. When the roller 3 is assembled, the first section of the roller 3 is rotationally fixed to the drive hub 33, such that the first section rotates with the drive hub 33. As such, the freewheel mechanism 2 transmits torque to the first section of the roller 3, via the drive hub 33, when the freewheel mechanism 2 is in the locked configuration.

The drive assembly 100 further comprises a differential 4. The differential 4 comprises a drive shaft 41 which is rotationally fixed to the roller drive gear 24, such that the drive section half-shaft 41 rotates with the roller drive gear 24.

Figure 13 shows a schematic close-up view of the differential 4 of the drive assembly 100. The differential 4 comprises a drive gear 42, two pinion gears 43 (one of which is removed from Figure 13 for clarity), a pinion carrier 44, and a driven gear 45. The drive gear 42 is configured to be driven by the drive shaft 41. The pinion carrier 44 carries the pinion gears 43, which are configured to transmit torque from the drive gear 42 to the driven gear 45. The driven gear 45 is rotationally fixed to the driven section 32 of the roller such that when the freewheel mechanism is in the locked configuration, drive is transmitted from the drive shaft to the roller drive gear, from the roller drive gear to the drive shaft 41, from the drive shaft 41 to the driven gear 45, via the pinion gears 43, and from the driven gear 45 to the second section 32 of the roller. The differential 4 allows the first and second sections of the roller to rotate at different speeds.

Figure 14 shows a schematic isometric view of a mower 10 comprising the dris assembly 100. The mower 10 comprises a handle 101 which allows a user to manoeuvre the mower 10. One or more controls for controlling operation of the mower 10 may be mounted to the handle 101. The mower 10 further comprises a cylinder blade (not shown) to provide the cutting function of the mower 10.

Figure 15 shows a schematic close-up view of the mower 10 in which various components of the drive assembly 100 are visible. The mower 10 comprises a fairing pan& 102 arranged to cover components of the drive assembly 100.

Figure 16 shows a schematic close-up view of the mower 10 with the fairing panel 102 removed. The drive assembly 100 further comprises a pulley assembly 5. The pulley assembly 5 comprises a drive pulley 51, a driven pulley 52, and a belt 53 configured to transmit torque from the driven pulley 51 to the drive pulley 52. The belt 53 is a fixed tension belt, in this embodiment, the mower 10 comprises a first electric motor (not shown) configured to drive the driven pulley 51. In other embodiments, the mower may comprise an internal combustion engine configured to drive the driven pulley 51. The mower 10 comprises a second electric motor (not shown) configured to drive the cylinder blade. The driven pulley 52 is mounted on an end of the drive shaft 1 distal from the drive gear 21 and is configured to drive the drive shaft 1. When the freewheel mechanism is in the first or second locked configuration, the freewheel mechanism transmits torque from the first electric motor, via the pully assembly 5, to the roller 3. When the freewheel mechanism is in the unlocked configuration, the roller 3 is able to rotate freely relative to the pulley mechanism 5.

In some embodiments, the drive assembly may be configured to move the mower 10 in a forward direction when the freewheel mechanism is in the first locked configuration. To switch the freewheel mechanism from the first locked configuration to the unlocked configuration in use, a user first brings the mower 10 to a stationary position and disengages a dutch between the first electric motor and the drive shaft to allow the drive shaft to come to a stationary position. The user then pulls the mower 10 towards them from the stationary position via the handle 101, to affect an initial rotation of the roller 3 and switch the freewheel mechanism to the unlocked configuration, in some embodiments, the freewheel mechanism may be configured such that pushing the mower 10 forwards switches the freewheel mechanism from the first locked configuration to the unlocked configuration. With the freewheel mechanism in the unlocked configuration, the user is able to manually push the mower in a forward direction or pull the mower 10 in a backward direction, via the handle, without having to overcome the inertia of the electric motor. To switch the freewheel mechanism to the locked configuration, the user brings the mower 10 to a stationary position before switching the first electric motor on to cause an initial rotation of the drive shaft.

Claims

CLAIMSA drive assembly for a mower, comprising: a drive member; a roller; and a freewheel mechanism switchable between a locked configuration and an unlocked configuration, wherein the freewheel mechanism is configured to transmit torque from the drive member to the roller in the locked configuration and allow the roller to rotate freely relative to the drive member in the unlocked configuration; wherein the freewheel mechanism is switchable from the locked configuration to the unlocked configuration by rotating the roller relative to the drive member and switchable from the unlocked configuration to the locked configuration be rotating the drive member relative to the roller.
2. The drive assembly of claim I. wherein in the unlocked configuration, the freewheel mechanism allows the roller to rotate freely relative to the drive member in a first direction and a second direction, opposite the first direction.3. The drive assembly of claim 1 or claim 2, wherein the freewheel mechanism is switchable from the locked configuration to the unlocked configuration by rotating the roller relative to the drive member in either direction.
3. The drive assembly of any preceding claim, wherein the drive member comprises a drive shaft and the freewheel mechanism comprises a cam rotatably fixed to the drive shaft.
4. The drive assembly of claim 3, wherein the freewheel mechanism comprises a clutch hub comprising a plurality of fixed elements configured to surround and receive the cam, the fixed elements defining a plurality of spaces therebetween.
5. The drive assembly of claim 4, wherein the freewheel mechanism comprises a switch gear configured to drive the dutch hub.
6. The drive assembly of claim 5, wherein the freewheel mechanism comprises a roller ring gear configured to be driven by the roller and configured to drive the switch gear; wherein
7, Thc drive assembly of claim 5 or claim 6, wherein the switch gear is plastic.
8. The drive assembly of any preceding claim, wherein the freewheel mechanism comprises a plurality of rolling elements.
9. The drive assembly of claim 8, when dependent on any of claims 4 to 7, wherein the freewheel mechanism comprises a clutch housing configured to receive the clutch hub, wherein the plurality of rolling elements are configured to be received within the spaces between the fixed elements of the clutch hub to extend between a drive surface of the cam and a circumferential internal surface of the clutch housing.
10. The drive assembly of claim 9, wherein the freewheel mechanism comprises a drive gear configured to be driven by the clutch housing.
11. The drive assembly of claim 10, wherein the freewheel mechanism comprises a roller drive gear configured to be driven by the drive gear and configured to drive the roller
12. The drive assembly of any of claims 8 to I I, wherein the plurality of rolling elements are configured to adopt a locked position when the freewheel mechanism is in the locked configuration.
13. The drive assembly of claim 12, when dependent on any of claims 9 to 11, wherein the rolling elements contact the drive surface of the cam and the circumferential internal surface of the clutch housing when in the locked position to transfer drive between the cam and the clutch housing.
14. The drive assembly of any of claims 8 to 13, wherein the plurality of rolling elements are configured to adopt an unlocked position when the freewheel mechanism is in the unlocked configuration.
15. The drive assembly of claim 14, when dependent on any of claims 9 to I I, or when dependent on claim 12, when dependent on any of claims 9 to II, or when dependent on claim 13, wherein the rolling elements are spaced apart from one or both of the drive surface of the cam and the circumferential internal surface of the clutch housing when in the unlocked position to allow the clutch housing to rotate freely relative to the cam,
16. The drive assembly of claim 14 or claim 15, when dependent on claim 12 or claim 13, wherein the dutch hub is configured to be rotated by the drive shaft relative to the cam to cause the fixed elements to move the rolling elements to adopt the unlocked position from the locked position,
17. The drive assembly of claim 16, or claim 14 or claim 15, when dependent on claim 12 or claim 13, wherein the cam is configured to be rotated by the drive shaft relative to the clutch hub to cause the rolling elements to adopt the locked position from the unlocked position.
18. The drive assembly of any preceding claim, wherein the freewheel mechanism comprises a friction member and a spring, wherein the friction member and the spring are configured to provide a friction fit between the clutch hub and the switch gear.
19. The drive assembly of any preceding claim, vherein the roller comprises a first section and a second section, comprising a differential configured to allow the first section and the second section to rotate at different speeds.
20. The drive assembly of any preceding claim, comprising a drive pulley, a driven pulley, and a belt configured to transmit torque from the driven pulley to the drive pulley, wherein the driven pulley is configured to transmit torque from the belt to the drive member.
21. The drive assembly of claim 20, wherein the belt is a fixed tension belt.
22. A mower comprising the drive assembly of any preceding claim.
23. The mower of claim 22, comprising a cylinder blade.
24. The mower of claim 23, comprising a first motor configured to deliver torque to the drive member and a second motor configured to deliver torque to the cylinder blade.