Field

The present invention relates to a device for adjusting the position of a component relative to a support to which the component is mounted. The invention also relates to an assembly which includes the device, the support and the component. Moreover, the invention relates to a method of forming such an assembly, including in particular a retrofit method.

Background

One application of the invention is adjustment of tension in a chain or belt trained over a sprocket or pulley, respectively, of which the component is comprised. Another application of the invention is adjustment of the position of a wheel, which is supported from the support and of which the component is comprised, arranged to engage a surface of the ground to hold the support clear of the ground, such that a spacing between the support and the ground is adjusted. Yet another application of the invention is adjustment of the position of a gauge wheel, which is supported from the support and of which the component is comprised, arranged to engage a surface of the ground upon the displacement of an implement, in a direction from the support to the ground, reaching a threshold - which may be such that the implement is above the ground, is in contact with the ground surface or at least partially penetrates the ground - to preclude further displacement of the implement, beyond the threshold, in said direction.

Satisfactory operation of a chain or belt drive assembly typically requires that tension in the chain or belt be maintained within a particular range during operation. Frequently necessary to this end is an arrangement dedicated specifically to imparting loading to the chain or belt which is transverse to, though generally coplanar, with the direction of travel of the chain/belt. Such an arrangement often comprises a sprocket or pulley, commonly termed “an idler” over which the chain or belt, respectively, is trained, and a mechanism to adjust the position of the sprocket/pulley relative to the chain/belt to control the degree of engagement between the sprocket/pulley and the chain/belt, and thus the tension in the latter.

In one conventional such arrangement, the structure from which the sprocket/pulley is supported is configured with a slot, and a bolt is received centrally through the sprocket/pulley (typically to form a fit with a bearing in/of the sprocket/pulley) and also through the slot, and fastened by a nut tightened on the end of the bolt, whereby the sprocket/pulley is rotatably mounted to the structure adjacent one side of the slot and maintained against the chain or sprocket by frictional engagement between the structure and the assembly comprising the nut/bolt and sprocket/pulley. Loosening of the nut allows for translational sliding of the bolt/nut and sprocket/pulley assembly relative to the support structure, and thus movement of the bolt along the slot to adjust the position of the sprocket/pulley relative to the chain/belt to increase or decrease the degree of engagement between the sprocket/pulley and the chain/belt and thus the tension in the latter (prior to retightening of the nut to fasten the assembly, again via the aforementioned frictional engagement).

An advantage of such an arrangement is that it is simple and inexpensive to implement. A disadvantage of such an arrangement, however, is that the frictional engagement may be insufficient to hold the idler in position against the reaction force exerted on it by the chain/belt. This disadvantage may be realised in particular where the drive assembly is run in reverse, whereby the chain/belt section against which the sprocket/pulley bears is a “driving” section, instead of a “driven” section, and subjected to considerable tension by the drive source, such that the reaction force it exerts on the sprocket/pulley is large.

Summary of the Invention

According to a first aspect of the present invention, there is provided a device for adjusting the position of a component, relative to a support to which the component is mounted via a member received by a track with which the support is configured, the device comprising a body and being configured to be coupled to the support such that the body is rotatable relative to the support, in one of clockwise and anticlockwise directions, about an axis which is perpendicular to the track, the body including a radially outwardly facing cam surface which is arranged to abut the member slidably and is of increasing radial distance from the axis in the other of said directions, such that the rotation of the body in said one direction effects a net displacement of said member, relative to the support, along the track, in a direction away from said axis, and thus adjustment of said position.

According to a second aspect of the present invention, there is provided an assembly comprising: a device according to any one of the preceding claims; said support, configured with said track; said component; and said member, wherein: the component is mounted to said support such that said member is received by said track; and said device is coupled to the support such that that the body is rotatable relative to the support in said one direction about said axis, such that the rotation of the body effects the displacement of said member, relative to the support, along the track and thus said adjustment.

In a preferred embodiment of the invention, said member comprises or defines a shaft which is received by the track and on which the component is mounted.

Preferably, the device comprises a fitting which is engageable with a corresponding fitting portion on the support such that the body is coupled to the support. Preferably, the fitting comprises a projection extending from the body to be engageable with the fitting portion.

Preferably, the projection is arranged to be received in a slot defining said track, said slot thus defining the fitting portion. Preferably, the projection is arranged to be received in an end of said slot away from which said member is displaced, relative to the support, by said rotation, the end thus defining the fitting portion.

Preferably, the projection comprises a pin or shaft.

Preferably, the cam surface is configured such that a rate of increase in the radial distance of said portions thereof from the axis decreases in said one direction.

Preferably, the cam surface is configured so as to tend, and/or such that said portions thereof tend, towards and/or approach being tangential in said one direction.

Preferably, the cam surface portions substantially conform to or approximate an involute of a curve about said axis. Preferably, the cam surface portions substantially conform to or approximate an involute of a circle about said axis.

Preferably, the body is configured with a track arranged to receive said member, the track defining said radially outwardly facing cam surface and defining a radially inwardly facing surface which is radially outward of and extends generally parallel to the radially outwardly facing cam surface and is arranged to abut the member, such that one of the body and the member is retained to the other, and/or arranged to abut the member slidably, such that rotation of the body relative to said support in said other direction effects displacement of said member, relative to the support, along the track in a direction towards said axis, and thus adjustment of said position whereby said inwardly facing surface is an inwardly facing cam surface. Preferably, the device comprises a channel or slot defining the track with which the body is configured.

In the device according to a preferred embodiment of the invention, the device - preferably the body thereof- is configured with indicia arranged to indicate, for each of plural positions along the surface, a value corresponding to a spacing between the axis and the member when abutted by a said radially outwardly facing cam surface portion at that position and/or corresponding to a spacing between a reference position on the track and the member when abutted by a said radially outwardly facing cam surface portion at that position. Preferably, the indicia are arranged on the body radially outward of the radially inwardly facing surface. Preferably, the indicia are arranged on a face of the body opposite to said face which is perpendicular to said axis. Preferably, the device is configured so as to be compressed between said member and said support under loading borne by the component in a direction towards said axis to preclude the member from being displaced, relative to the support, along the track in that direction. In a preferred embodiment of the invention, the device is for adjusting the position of a rotatable component of which the component which is mounted to the support is comprised.

In a preferred embodiment of the invention, the device is for adjusting the position of a sprocket or pulley of which said rotatable component is comprised.

In a preferred embodiment of the invention, the device is for adjusting the position of a chain- or belt-tensioning sprocket or pulley constituting said sprocket or pulley of which said rotatable component is comprised. In preferred versions of embodiments of the invention, including of embodiments in which the device is for adjusting the position of a said sprocket or said pulley, the device is configured or arranged such that the rotation of the body in said one direction effects absolute movement of said member and thus said displacement of said member relative to the support. Preferably, in such versions, the device is configured or arranged such that said axis remains fixed relative to said support during said movement and/or said support remains absolutely stationary during said movement.

In a preferred embodiment of the invention, the device is for adjusting the position of a wheel of which said rotatable component is comprised. In a preferred embodiment of the invention, the device is for adjusting the position of a ground- engaging wheel constituting said wheel of which said rotatable component is comprised.

In a preferred embodiment of the invention, the device is for adjusting the position of a ground- engaging wheel arranged to support said support over the ground and constituting said wheel of which said rotatable component is comprised.

In a preferred embodiment of the invention, the device is for adjusting the position of a gauge wheel constituting said wheel of which said rotatable component is comprised Preferably, the device is hand-operable such that the rotation of said body can be effected. Preferably, the body is hand-graspable such that the rotation thereof can be effected. Alternatively, the device may be engageable by a tool, e.g. a wrenching tool, operable to apply torque to the body to rotate the body. Preferably, the body comprises a face which is perpendicular to said axis and receivable against a corresponding face of said support so as to slide thereagainst during the rotation.

Preferably, the body is releasably lockable against said rotation relative to the support, so as to retain said member in its position.

Preferably, the assembly includes a fastening assembly which comprises said member and a bearing portion attached to said member, and configured such that the body is arranged between said bearing portion and said support and the fastening assembly is tightenable to clamp the body between the bearing portion and the support, thereby frictionally locking the body against said rotation relative to the support, and loosenable to permit said rotation.

Preferably, the track with which said support is configured is linear. Preferably, the support comprises a plate configured with said track.

The assembly according to a preferred embodiment is such that said direction away from the axis is a direction towards a chain or belt trained over the sprocket or pulley whereby, upon the displacement of said member, relative to the support, in that direction, a load which is transverse to the chain or belt and perpendicular to said axis and which is exerted on the chain or belt by the pulley or sprocket over which it is trained, and thus tension in the chain or belt, is increased.

Preferably, in the assembly of that embodiment, the body is configured with the track defining said radially outwardly facing cam surface and radially inwardly facing surface, such that said direction towards the axis is a direction away from the chain or belt whereby, upon the displacement of said member, relative to the support, in that direction, said load exerted on the chain or belt, and thus the tension in the chain or belt, is decreased.

The assembly according to another preferred embodiment is such that said direction away from the axis is a direction towards a surface to be engaged by said wheel.

According to a third aspect of the present invention, there is provided a harvester front including: a support structure; a feeder drum rotatably mounted to the support structure; the assembly of the second aspect, said support of which is defined by said support structure; said chain or belt trained over the sprocket or pulley; a sprocket or pulley over which said chain or belt is trained and which is coupled or coupleable to a drive source of the harvester front or of a harvester vehicle to which the harvester front is to be mounted for operation so as to be rotatable by the drive source ("the drive sprocket or pulley"); and a sprocket or pulley over which said chain or belt is trained such that rotation is imparted thereto by the chain or belt during rotation of the drive pulley by the drive source ("the driven sprocket or pulley"), the driven sprocket or pulley being coupled to the feeder drum such that the rotation imparted thereto effects rotation of the feeder drum, wherein the sprocket or pulley of said assembly is downstream of the driving sprocket or pulley and upstream of the driven sprocket or pulley in a direction in which the chain or belt travels when the rotation of the drive sprocket is in a sense which is such that the rotation of the feeder drum is in an operating direction thereof.

According to a fourth aspect of the present invention, there is provided method of forming an assembly according to the second aspect, comprising coupling the device to said support such that that the body is rotatable relative to the support in said direction(s) to effect the displacement of said member, relative to the support, along the track and thus said adjustment.

Preferably, the assembly is that of said harvester front of the third aspect.

Preferably, coupling of the device to the support comprises retrofitting the device. Preferably, the method is such that, within said assembly, a subassembly comprising the device, component and member replaces an initial subassembly, comprising a component and a member received by said track and via which that component was mounted to the support, the initial subassembly being such that said member thereof was displaceable, relative to the support, along the track, to effect adjustment of the position of the component thereof relative to the support, and thence releasably lockable to the support to preclude displacement of the member, relative to the support, along the track and thus retain the component in its position.

The method according to a preferred embodiment of the invention comprises: disassembling a subassembly comprising a component and a member received by said track and via which that component is mounted to the support ("the initial subassembly"), the initial subassembly being such that said member thereof is displaceable, relative to the support, along the track, to effect adjustment of the position of the component thereof relative to the support, and thence releasably lockable to the support to preclude displacement of the member, relative to the support, along the track and thus retain the component in its position; and thereafter forming a subassembly comprising the device, the component of said assembly and the member of said assembly so as to effect the coupling the device to said support.

Preferably, the member of said subassembly is the member of the initial subassembly. Preferably, the member of the initial subassembly was or is releasably frictionally engageable with the support so as to be releasably lockable relative to the support.

The method according to a preferred embodiment of the invention comprises arranging said projection such that it is received in the slot defining said track whereby the slot defines said fitting portion.

In the method according to a preferred embodiment of the invention, the initial subassembly was or is such that said component thereof comprises a sprocket or pulley over which said chain or belt was or is trained whereby: displacement of that sprocket or pulley, relative to the support, along the track in said direction away from the axis was or is so as to increase a transverse load exerted thereby on the chain or belt and thus tension in the chain or belt; and displacement of that sprocket or pulley, relative to the support, along the track in a direction opposite to said direction away from the axis was or is so as to decrease the transverse load exerted thereby on the chain or belt and thus the tension in the chain or belt.

In the method according to a preferred embodiment of the invention, said component of the initial subassembly comprises a wheel which was or is, or is replaced by, the wheel of said subassembly.

Preferably, the member of the initial subassembly was releasably frictionally engageable with the support so as to be releasably lockable relative to the support.

In a preferred embodiment of the invention, the sprocket or pulley of said subassembly is the sprocket or pulley of the initial subassembly.

Preferably, the member of said subassembly is the member of the initial subassembly.

Preferably, the method comprises arranging said projection such that it is received in the slot defining said track whereby the slot defines said fitting portion.

Brief Description of the Drawings

The invention will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which: Figure 1 A is a front view of a harvester front, showing a feeder drum of the front;

Figure IB is a side view of the harvester front showing details of a chain drive assembly which forms a part of the harvester front and includes an adjustment device according to a first embodiment of the present invention; Figures 2A, 2B and 2C show configurations of the device when tensioning a chain of the assembly to minimum, intermediate and maximum extents respectively (Figure 2B being detail “2B” shown in Figure 1);

Figure 3A is a further view showing the configuration of the device in the intermediate configuration;

Figure 3B is a view of section “3B” marked in Figure 3A;

Figures 4A and 4B are rear and front perspective views, respectively, of the device;

Figures 5A and 5B are rear and front perspective views, respectively, of an adjustment device according to a second preferred embodiment of the present invention; Figures 6A and 6B are rear and front perspective views, respectively, of an adjustment device according to a third preferred embodiment of the present invention;

Figures 7A and 7B are rear and front perspective views, respectively, of an adjustment device according to a fourth preferred embodiment of the present invention; and

Figure 8 is a section view, corresponding to Figure 3B, showing details of a pre-existing position-adjustable subassembly into which the device according to any one of the first to fourth embodiments is integratable;

Figure 9 is a schematic front elevation view of an alternative assembly including an adjustment device according to a preferred embodiment of the present invention;

Figure 10A is a cross-sectional elevation view showing details of a pre-existing position- adjustable subassembly into which the device is integrated such that the assembly of Figure 9 is formed;

Figure 10B is a cross-sectional elevation view showing details of a position-adjustable subassembly formed by integrating the device into the sub-assembly of Figure 10A; and

Figure 11 is a front view of an adjustment device according to a fifth preferred embodiment of the present invention.

Detailed Description

Shown in Figures 1A, IB, 2A to 2C and 4A and 4B, are details of a harvester front 200 and, more particularly, an assembly 100 forming a part thereof and arranged to rotate a feeder drum 150 of the harvester front 200. The harvester front 200 and feeder drum 150 in this particular example are as disclosed in the complete specification (including drawings) of Australian Innovation Patent No. 2017101797 (AU2017101797 B9), the disclosure in which is incorporated herein by reference.

The harvester front 200 includes a support structure 250, from which the feeder drum 150 is rotatably supported at each one of opposite ends thereof.

The assembly 100 includes a drive sprocket 110, rotatably mounted to the support structure 250 and coupled to a motor (not shown) of the harvester front 200 so as to be rotatable by the motor, and a driven sprocket 120 coupled to the feeder drum 150 to impart rotation thereto. The assembly 100 further includes a continuous chain 130 which is trained over the drive 110 and driven 120 sprockets such that the rotation of the former sprocket drives the rotation of the latter sprocket and thus the feeder drum 150 to which it is coupled. The assembly 100 further includes a tensioner sprocket, i.e. “idler” 140, which is positioned so as to be urged sideways against a section 132 ofthe chain 130whichis drawn by and onto the sprocket 120 when the rotation of the feeder drum 150 is in the direction of normal operation of the feeder drum 150, and which section constitutes the low-tension or “driven” section of the chain 130 in that case (the chain section 134 which in such circumstances is drawn by and onto the sprocket 110 constituting the high-tension or “driving” section of the chain 130). The sprocket 140 is thus downstream of the driving sprocket 110 and upstream of the driven sprocket 120 in a direction in which the chain 130 travels when the rotation of the drive sprocket 110 is in a sense such that the feeder drum rotates in its operating direction. The sideways loading exerted by the sprocket 140, on the chain section 132 thus trained thereover, when the position of which sprocket is appropriately set, serves to tension the section 132 at a level which is satisfactory to ensure reliable sustained driving operation of the feeder drum 150.

The sprocket 140 is rotationally mounted to a support section 160 defined by part of the support structure 250. More particularly, referring also to Figure 3B, the sprocket 140 is rotatably mounted to the support section 160 via a bolt 80, a shank 81 of which extends through a slot 165 formed through the support section 160 and through a bearing 141 ofthe sprocket 140. A nut 83 is received over a leading end of the shank 81 to retain the bolt 80.

The assembly 100 comprises a device 1 for adjusting the position of the sprocket 140, relative to the support 160. Referring to Figure 8, the device 1 (which will be described in detail shortly) is integratable with components of a pre-existing subassembly 300, comprising bolt 80, nut 83 and sprocket 140. The subassembly 300 includes a first seating part 142A at one side of the bearing 141, the first seating part 142A having a first portion, configured in the form of a collar, which projects laterally outwardly from, or from adjacent, the inner race of bearing 141, and a second portion, configured in the form of a flange, which projects radially outwardly from a laterally outer end of the first portion to be able to abut the inside face 161 of the support 160. The subassembly 300 also includes a second seating part 142B, at the other side of the bearing 141, having a first portion, configured in the form of a collar, which projects laterally outwardly from, or from adjacent, the inner race of bearing 141, and a second portion, configured in the form of a flange, which projects radially outwardly from a laterally outer end of that first portion to be able to abut the underside of the nut 83. Either or each of seating parts 142A and 142B may be integrated with the inner race or instead defined by a separate element the laterally inner end of the first portion of which is arranged so as to abut a respective laterally outer side face of the inner race. The bolt 80, with the nut 83 slackened, is displaceable along the slot 165 to adj ust the position of the sprocket and thus the loading it exerts on chain 130. Tightening of the nut 83 causes clamping of the inner race of bearing 141 between the first portions of the seating parts 142A and 142B, and thus abutment between the second portion of the first seating part 142A and the inside face 161 of support section 160 and abutment between the second portion of the second seating part 142B and the underside of the nut 83, whereby the sprocket 140 is secured laterally. In turn, support section 160 is clamped between the first seating part 142A (specifically the second portion thereof) and the bolt head 82, the resulting frictional engagement between the subassembly 300 and the support section - specifically, the engagement between the outer face 162 of support section 160 and the underside of the bolt head 82 and the engagement between the laterally outer face of the second portion of the first seating part 142A and inner face 161 - locks the subassembly to the support section 160, for the purposes of retaining the subassembly 300 at the set position relative to the slot 165. For the purposes of ensuring adequate frictional engagement, the laterally outer face of the second portion of the first seating part 142 A and the underside of the bolt head 82 are sufficiently dimensioned transverse to the bolt axis so as to seat against the faces 161 and 162 respectively to either side of the slot 165.

The second seating part 142B can, provided the underside of nut 83 is dimensioned appropriately to engage the bearing inner race directly, be omitted.

On occasion, and particularly where there is an excessive build-up of cut crop material on or under the feeder drum 150, it is necessary to rotate the feeder drum 150 in reverse - by driving the sprocket 110 in a sense opposite to that shown in Figure 1. In such a case, the section 132 is the driving/high- tension section (the section 134 then being the driven/low-tension section), whereby the subassembly 300 is subjected to a significantly greater reaction force exerted on it by the section 132, which reaction force may be sufficient to overcome the frictional resistance offered by the clamping between the subassembly 300 and the support section 160 and thus cause displacement of the sprocket 140 in a direction away from the chain 130, which necessitates readjustment of the subassembly 300 to return the sprocket 140 to its correct position.

Referring to Figures 3B, 4A and 4B, the device 1 comprises a body 2, configured in the form of a disc and having parallel front 2A and rear 2B faces. The body is preferably formed of metal, and may be, for example, moulded or machined from plate. The device 1 further includes a round spigot or pin 5 attached to the body 2 such that it projects from face 2B in a direction perpendicular thereto. Manipulation of the device when in situ causes it to rotate about the central axis A of the projection 5, as will be described in further detail below.

The body 2 is configured with a curved slot 7 which is closed at opposite ends 7A and 7B thereof and which opens through faces 2A and 2B. The slot 7 defines a radially outwardly facing cam surface 3 and a radially inward facing cam surface 8. The device 1 is designed such that the body 2 is to be interposed between the bolt head 82 and the support section 160, and the projection 5 received in the slot 165 at the end thereof which is furthest from the chain section 132. In this regard, retrofit installation of the device 1 comprises removal of nut 83 from bolt 80, withdrawal of the bolt 80 from the seating part(s) 142 and bearing 141 and the slot 165, positioning the device 1 such that the rear face 2B is received against the support section outer face 162 and the projection 5 is received by the slot 165 at the upper end thereof, and then inserting the bolt 80 through the curved slot 7, slot 165 and the seating part(s) 142 and bearing 141, and reconnecting the nut 83 to the leading end of the bolt 80, such that a subassembly 300', comprising the bolt 80, nut 83, seating part (s) 142, and sprocket 140/bearing 141 and device 1, is adjustably mounted to the support section 160.

The slot 7 is configured in the form of a spiral whereby a distance R between the axis A and the cam surface 3 increases, in a clockwise direction, from end 7A to end 7B. The surfaces 3 and 8 are substantially parallel along the length of the slot 7, whereby a width W of the slot 7 is substantially uniform throughout the length thereof. The width W is the same as or similar to the width of slot 165, i.e. about the same as the diameter of the shank 81.

The slot 7, and thus each of cam surfaces 3 and 8, substantially conforms to or approximates an involute of a curve, such as a circular arc, about the axis A. In the direction from end 7A to end 7B, the angle between the cam surface 3 and the radius arm R approaches 90 degrees - i.e. the surface 3 tends towards being (though does not quite become) tangential in that direction.

When the device 1 is thus installed, the cam surface 3 is arranged so as to abut slidably the shank of the bolt 81, and the projection 5 is received by the slot 165 and arranged to engage an end thereof which is furthest from the chain section 132, that end thus defining a fitting portion. The projection 5 has a cross-sectional diameter similar to that of a semicircular face of the support section 160 defined at the end, whereby the projection 5 seats snugly against that face, so as to slide thereagainst during rotation of the device 1.

With the nut 83 slackened, rotation of the device 1 in a clockwise direction causes cam surface 3 to slide against bolt shank 81 and, because of the increasing radial distance of the former from the axis A, to urge the shank 81 towards the forward end of the slot 65 (being the lower end of that slot in the example illustrated) and thus urge the sprocket 140 to a greater extent against the chain section 132, as shown in Figures 2A to 2C. As the sprocket 140 is advanced, the reaction force exerted upon it by the chain section 132 increases, as does, correspondingly, the force which the body portion 2 must exert on the shank 81 to displace the sprocket 140 a given distance towards the chain section 132. Advantageously, owing to the cam surface 3 tending towards being tangential, the degree to which the sprocket 140 is displaced, for a given angular extent to which the device 1 is rotated about axis A, decreases, whereby rotation of the device 1 by hand (in a dial-like manner) remains possible throughout the length of the slot 7, thanks to an attendant mechanical advantage.

Upon the device 1 having been rotated to the appropriate extent, tightening of the nut 83 secures the sprocket 140 laterally (i.e. locks it against translational displacement parallel to the shank 81), and results in abutment between the body surface 2A and the underside of the bolt head 82 as well as abutment between the support section outer surface 162 and the body surface 2B (see Figure 3B), whereby the device 1 is likewise retained laterally and is correctly seated owing to the receipt of surface 2B against surface 162 and the receipt of the projection 5 against the portion of the support section 160 defining the rear end of the slot 165.

Owing to the spiral -like form of the cam surface 3, that surface is sufficiently transverse (along the length direction of the slot 7) to the radius arm R at any position along that surface that the component of the reaction force exerted on the body 2 by the shank 81, which force is taken through the face 3, which component is perpendicular to the radius arm R, is small. Accordingly, reliance is not placed on friction to hold the sprocket 140 in position as is the case with assembly 300; rather the supported offered by section 160 to the sprocket is instead conferred by abutment between the section 160 and the projection 5 (at the rear/upper end of the slot 165) and abutment between the cam surface 3 and the shank 81, the device 1 thus transmitting force from the support section 160 to the bolt 80/sprocket 140 as a result of being compressed between the former and the latter. As a result, the nut 83 need be tightened only to an extent sufficient to effect the aforementioned lateral retention of the sprocket 140 and device 1 - e.g. so as to be snug tight. In the case of a significant increase in the reaction force exerted by the shank 81 on the body 2 (through surface 3), such as when the feeder drum 150 is operated in reverse, the portion of the device 1 compressed between the slot end and shank precludes displacement of the latter towards the former, whereby the correct position of the sprocket 140 is maintained.

Operation of the device 1 in a manner so as to reduce the extent to which it urges the sprocket 140 against the chain section 132 comprises, with the nut 83 slackened, rotation of the body 2 (similarly effectible by hand) in a clockwise direction. At least from the point at which there is negligible or no residual tension in the chain causing it to exert a reaction force on the sprocket 140, cam surface 8 abuts the shank 81 and slides thereagainst during the rotation, thus displacing the shank 81 towards the rear end of the slot 165, as a result of the progressively decreasing radial distance R between the surface 8 and the axis A in the direction towards slot end 7A. Advantageously, the adjustability of the position of the bolt 80 in the slot 165, and thus the position of sprocket 140 relative to the chain 130, is bidirectional.

In the description of the embodiments, common reference numerals will be used to denote and refer to the same or corresponding features. The device 1, owing to the cam surface 3 thereof being smooth throughout its length, is configured such that the portions of the surface 3 arranged to engage the shank 81 are so arranged throughout a continuum, and the device 1 is thus, correspondingly, operable to adjust the position of the sprocket 140 throughout a continuum. Shown in Figures 5A and 5B is a device G according to a second preferred embodiment of the present invention, this device being identical to the device 1 with the exception that the radially outwardly facing cam surface is a corrugated or serrated surface 3', defining, in a direction from one end thereof to the other, regularly spaced apart peaks 3A and concave troughs 3B each arranged between the peaks in a respective pair of adjacent peaks. Each trough 3B is configured generally to conform circumferentially to the shank 81 when brought into engagement therewith (by rotation of the device G in the anticlockwise direction), such that there is formed a rotational interlock between the former and the latter, the interlock precluding any undesirable rotation of the device l'/displacement of the bolt 80/sprocket 140. The adjustability of the bolt 80/sprocket 140 in the direction towards the chain section 132 (by rotating body 2' anticlockwise by hand) is thus incremental, rather than continuous, each increment being defined by a respective trough 3B. In the device G, the portions of the surface 3’ arranged to engage the shank 81 are so arranged at spaced positions, those portions being defined by respective ones of the troughs 3B. A further advantage of the provision of the curved slot 7/7' through the body 2/2' in the device 1/1', additional to rendering the device 1/1' operable to adjust the position of the shank/shaft 81 additionally in the direction away from the chain section 132 (owing to the resulting cam surface 8 defined thereby), is that the body 2/2' includes a portion radially outward of the cam surface 3/3' that is arranged for receipt between the bolt head 82 and the support section 160, as can readily be seen at Figures 2A to 2C and Figure 3A. More particularly, each of surfaces 2A and 2A' includes a portion which is radially outward of the cam surface 3/3' and is arranged for receipt of a portion of the bolt head underside thereagainst, contributing to correct seating of that bolt head 82 against the body 2/2', while each of surfaces 2B and 2B' includes a portion, likewise radially outward of the cam surface 3/3', which is received against the support section outer surface 162, contributing to correct seating of the body 2/2' against the support section 160.

Notwithstanding, the invention may be embodied in devices rotatable only to displace the shank 81 toward the front end of the slot 165. One such device is device 1", shown in Figures 6A and 6B, which accords with a third preferred embodiment of the present invention. The device 1" is identical to the device 1 but for the body 2" thereof not including a radially outer portion as mentioned above .

Shown in Figures 7A and 7B is a device G" according to a fourth preferred embodiment of the present invention. The device G" differs from the device G in exactly the same way as the device 1" differs from the device 1. It is envisaged that in many applications the seating of the bolt head 82 against the body 272'" will nevertheless be adequate, notwithstanding that the bolt head underside will engage the body outer surface 2A72A'" only to one side of the shank 81. However, as and if appropriate, the device 17 G" may be supplemented with a suitably configured element arranged between the bolt head 82 and body 2" - e.g. a washer, possibly an eccentric one, received over shank 81 - to abut the surface 2A" over a greater area thereof than that which is abutted by the underside of the bolt head.

Shown schematically in Figure 9 is another apparatus 200', e.g. a lawnmower, including an adjustment device in accordance with an alternative preferred embodiment of the present invention. The apparatus 200' includes a support structure 250', which where the apparatus 200' is a lawnmower comprises a housing that shields the cutter(s) of the lawnmower, and at least one ground-engaging wheel 140' which is mounted to the support structure 250' and adjustable in position such that the spacing of the support structure 250' (and thus of the housing and cutter(s) in the case of a lawnmower) over the ground can be varied.

The wheel 140' is rotationally mounted to a support section 160' defined by part of the support structure 250' - e.g. a plate secured to the lawnmower housing. More particularly, referring also to Figure 10B, the wheel 140' is rotatably mounted to the support section 160' via bolt 80, the shank 81 of which extends through slot 165' formed through the support section 160' and through a bearing 141 of the wheel 140'. Nut 83 is received over the leading end of the shank 81 to retain the bolt 80.

The apparatus 200' comprises a device 1"", shown in Figure 11, for adjusting the position of the wheel 14G, relative to the support 160'. The device 1"" (which will be described in detail shortly) is integratable with components of a pre-existing subassembly 400, shown in Figure 10A, comprising bolt 80, nut 83 and bearing 141/wheel 140'. The subassembly 300 includes first seating part 142A at one side of the bearing 141, the first seating part 142A having a first portion, configured in the form of a collar, which projects laterally outwardly from, or from adjacent, the inner race of bearing 141, and a second portion, configured in the form of a flange, which projects radially outwardly from a laterally outer end of the first portion to be able to abut the outside face 162' of the support 160'. The subassembly 300 also includes a second seating part 142B, at the other side of the bearing 141, having a first portion, configured in the form of a collar, which projects laterally outwardly from, or from adjacent, the inner race of bearing 141, and a second portion, configured in the form of a flange, which projects radially outwardly from a laterally outer end of that first portion to be able to abut the underside of the nut 83. Either or each of seating parts 142A and 142B may be integrated with the inner race or instead defined by a separate element the laterally inner end of the first portion of which is arranged so as to abut a respective laterally outer side face of the inner race. The bolt 80, with the nut 83 slackened, is displaceable, relative to the support 160', along the slot 165' to adjust the position of the wheel 140'. Tightening of the nut 83 causes clamping of the inner race of bearing 141 between the first portions of the seating parts 142A and 142B, and thus abutment between the second portion of the first seating part 142A and the outside face 162' of support section 160' and abutment between the second portion of the second seating part 142B and the underside of the nut 83, whereby the wheel 140' is secured laterally. In turn, support section 160' is clamped between the first seating part 142A (specifically, the second portion thereof) and the bolt head 82, the resulting frictional engagement between the subassembly 400 and the support section - specifically, the engagement between the inner face 16 G of support section 160' and the underside of the bolt head 82 and the engagement between the laterally outer face of the second portion of the first seating part 142A and outer face 162' - locks the subassembly to the support section 160', for the purposes of retaining the subassembly 400 at the set position relative to the slot 165'. For the purposes of ensuring adequate frictional engagement, the laterally outer face of the second portion of the first seating part 142 A and the underside of the bolt head 82 are sufficiently dimensioned transverse to the bolt axis so as to seat against the faces 162' and 16G respectively to either side of the slot 165'. The second seating part 142B can, provided the underside of nut 83 is dimensioned appropriately to engage the bearing inner race directly, be omitted.

On occasion, such as where the apparatus 200' traverses rough terrain, shock or dynamic loading in the wheel may be sufficient to overcome the frictional resistance offered by the clamping between the subassembly 400 and the support section 160' and thus cause displacement of the support structure 250' (and thus the housing and cutter(s) in the case of a lawnmower) relative to the wheel 140', i.e. in a direction towards the ground, undesirably reducing the height of the former over the latter (or the spacing between the former and the latter), which necessitates readjustment of the subassembly 300 to return the sprocket 140 to its correct position.

Shown in Figure 11 is device 1"", which is designed to be integrated with the components of the subassembly 400 such that, inter alia, this problem can be eliminated. The device 1"" is identical to the device 1 with the exception that the body 2, specifically the surface 2A thereof, is marked with a series of indicia 11, each comprising a respective number, spaced apart along and adjacent to the curved slot 7. The indicia 11 in the example illustrated are arranged on the portion of the body 2 which is radially outward of the curved slot 7, defining the radially inwardly facing cam surface 8, whereby there is a relatively large amount of space over which to arrange them, though in other examples may be arranged on the portion of the body 2 which is radially inward of the curved slot 7, defining the radially outwardly facing cam surface 3.

The device G" is designed such that the body 2 is to be interposed between the support section 160' and the seating part 142A, and the projection 5 received in the slot 165' at the end thereof which is furthest from the ground. In this regard, retrofit installation of the device 1"" comprises removal of nut 83 from bolt 80, withdrawal of the bolt 80 from the seating part(s) 142 and bearing 141 and the slot 165', positioning the device 1"" such that the rear face 2B is received against the support section outer face 162' and the projection 5 is received by the slot 165 at the upper end thereof, and then inserting the bolt 80 through the curved slot 7, slot 165 and the seating part(s) 142 and bearing 141/wheel 140', and reconnecting the nut 83 to the leading end of the bolt 80, such that a subassembly 400', shown in Figure 10B, comprising the bolt 80, nut 83, seating part (s) 142, and sprocket

140/bearing 141 and device 1"", is adjustably mounted to the support section 160'.

When the device 1"" is thus installed, the cam surface 3 is arranged so as to abut slidably the shank of the bolt 81, and the projection 5 is received by the slot 165' and arranged to engage an end thereof which is furthest from the ground, that end thus defining a fitting portion. The projection 5 has a cross-sectional diameter similar to that of a semicircular face of the support section 160' defined at the end, whereby the projection 5 seats snugly against that face, so as to slide thereagainst during rotation of the device 1"". With the nut 83 slackened, rotation of the device 1"" in a clockwise direction causes cam surface 3 to slide against bolt shank 81 and, because of the increasing radial distance of the former from the axis A, to urge the projection 5 against the fitting portion at the upper end of the slot 165', thus upwardly displacing both the projection 5 and the support section/structure 1607250' whereby the spacing between the shank 81 and the forward end of the slot 65 (being the lower end of that slot in the example illustrated) is thus reduced. Rotation of the device 1"" in an anticlockwise direction causes cam surface 3 to slide against bolt shank 81 and, because of the decreasing radial distance of the former from the axis A, to allow the projection 5 to be displaced downwardly relative to the ground, under the loading exerted on it by the fitting portion, whereby the support section 160/support structure 250' is likewise displaced downwardly relative to the ground and the height thereof above, or spacing thereof over, the ground is thus reduced.

Advantageously, the indicia 11 are arranged to indicate, for each of plural positions along the cam surface 3, a value corresponding to a spacing between the axis A and the shank 81 when abutted by the cam surface 3 at that position and/or corresponding to a spacing between a given position along the slot 165' and the shank 81 when abutted by the cam surface 3 at that position. A person operating the device 1"" can thus use the indicia to sight and set the height of the support section/structure 1607250' from the ground.

Upon the device 1"" having been rotated to the appropriate extent, tightening of the nut 83 secures the wheel 140' laterally (i.e. locks it against translational displacement parallel to the shank 81), and results in abutment between the body surface 2A and laterally outer (second) portion of the first seating part 142A as well as abutment between the support section outer surface 162' and the body surface 2B (see Figure 10B), whereby the device 1"" is likewise retained laterally and is correctly seated owing to the receipt of surface 2B against surface 162 and the receipt of the projection 5 against the portion of the support section 160 defining the upper end of the slot 165'.

Again, owing to the spiral -like form of the cam surface 3, that surface is sufficiently transverse (along the length direction of the slot 7) to the radius arm R at any position along that surface that the component of the reaction force exerted on the body 2 by the shank 81, which force is taken through the face 3, which component is perpendicular to the radius arm R, is small. Accordingly, in the case of assembly 400' reliance is not placed on friction to hold the support section 160/support structure 250' in position as is the case with assembly 400; rather the support offered by wheel 140' to the support section 160' is instead conferred by abutment between the section 160' and the projection 5 (at the rear/upper end of the slot 165') and abutment between the cam surface 3 and the shank 81, the device 1"" thus transmitting force from the bolt 80/wheel 140' to the support section 160' as a result of being compressed between the former and the latter. As a result, the nut 83 need be tightened only to an extent sufficient to effect the aforementioned lateral retention of the wheel 140' and device 1"" - e.g. so as to be snug tight. In the case of a significant increase in the reaction force exerted by the shank 81 on the body 2 (through surface 3), the portion of the device 1"" compressed between the slot end and shank precludes displacement of the former towards the latter, whereby the correct position of the wheel 140' is maintained. The rotation of the device 1"" may be effected by hand. Alternatively, the device 1"" may be engaged or engageable by a tool, e .g . a wrenching tool, operable to apply torque to the body to rotate the body.

Device G may, without departure from the invention, instead be configured with indicia 11. Device 1" or device G" may also be configured with indicia, which indicia may be arranged on the surface 2 A and on a portion of the body 2 radially of the surface 3.

Possible without departure from the invention is an arrangement as shown in Figure 1 A though which comprises, instead of device 1, the device 1"", or any one of the devices G, 1", G" with or without the indicia, arranged in the same manner as device 1 shown in that drawing.

Also possible without departure from the invention is an arrangement as shown in Figure 10B though which comprises, instead of device 1"", the device 1, or any one of the devices G, 1" and G" with or without the indicia, arranged in the same manner as device 1"" shown in that drawing. In each of the illustrated embodiments, the handedness of the device is such that the direction of rotation thereof to advance the sprocket 140 or wheel 140' is anticlockwise. It will of course be appreciated, however, that the device may be oppositely handed (i.e. a mirror image of what is illustrated), in which case that direction is clockwise (and the direction for effecting/permitting retraction of the sprocket 140 or wheel 140' is thus anticlockwise, instead of being clockwise). In either case, the direction of rotation of the device to advance the sprocket 140 or wheel 140' is opposite to the direction along the radially outwardly facing cam surface in which that cam surface is of progressively increasing distance from the axis of rotation of the device. Also, it will be noted that, when the device of the invention is operated, depending on the application thereof, it can be either that the component moves and the track/slot (as well as the support structure configured therewith) remains stationary or vice versa; in either case it will be appreciated that the component/member is displaced along the track/slot relative to the support configured with that track/slot.

A particular advantage of the devices of the embodiments described with reference to the drawings is that the slot 165 is utilised for abutting and rotationally supporting the projection/shaft/pin 5. Nevertheless, also possible are embodiments in which a hole which is separate from the slot 165 is formed in the support section 160 to receive that shaft/pin/projection.

While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not by way of limitation. It will be apparent to a person skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the invention. Thus, the present invention should not be limited by any of the above described exemplary embodiments.

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

The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.