As is well known, an agricultural tine is usually made of spring steel and has an upper end which is mounted on a frame of an implement, such as a harrow, and which has a lower end provided with a soil-working tip which moves through the ground in order to carry out any required soil- working operations. The shape of the tip will depend upon the particular working operation to be performed, but evidently will be subjected to substantial wearing and impact forces during operation, which means that these components of a tine require regular replacement after an unacceptable level of wear has occurred, or in the event of damage of the component.

In order to reduce down time, during routine servicing or if necessary on site, it is necessary to provide a fastening system which is simple in construction, so that dis-assembly of a worn tip and assembly of a replacement tip can be carried out quickly and reliably, but which is also sufficiently robust so as to minimise risk of failure or accelerated wear in the mounting region of the tip on the tine.

As mentioned above, the shape of the tip will depend upon the particular soil-working operation which is required, and the tips of tines can therefore vary between a very simple design which is effectively a downwardly- projecting prong with a tapering or pointed end, and a more complicated shape, such as a so-called wing point share, which is substantially triangular in shape as seen in plane view.

However, existing triangular formations with a pointed forward end have a shape which resembles that of a snow plough i. e. it is formed of two blades which are joined together at their forward ends to form an arrowhead, but in which each blade is located in an oblique plane which extends laterally outwardly and upwardly of the forward pointed end. In other words, the arrowhead formation is generally triangular in shape, as seen in plan view, but as viewed in a horizontal direction perpendicular towards each blade, the blade extends upwardly from its lower horizontal cutting edge and obliquely towards the tine on which it is mounted.

The known design of arrowhead tip therefore functions in the manner of a snow plough, and exerts a loosening action on the soil through which it is pulled, but by reason of the shape of the tip the soil is distributed in two separate layers on either side of the forward pointed end.

Therefore, while this may be acceptable for some situations, it does not exert a uniform working action on the soil, and does not form a substantially uniform depth of worked soil i. e. not a uniform seedbed.

The invention seeks to improve this known triangular design of arrowhead formation, and thereby provide a working tip which is better able to create a seedbed of substantially uniform depth throughout the area of ground which is being worked by the tip, and yet which can easily and reliably be fitted to, and removed from the lower end of an agricultural tine.

According to the invention there is provided a soil- working tip for mounting on the lower end of an agricultural tine which is generally circular in cross-section, said tip being generally triangular, as seen in plan, and diverging from a pointed forward end, in which the tip comprises: a substantially flat arrowhead formation which is intended to be located in a plane substantially parallel to the surface of the soil to be worked, said formation defining said pointed forward end and diverging therefrom; a shank projecting obliquely upwardly and rearwardly of said arrowhead formation, said shank of the tip being connected at its forward lower end to said arrowhead formation and having a mounting portion at its opposite end which is at least partly tubular so as to be able to receive a lower end of the tine in order to mount the tip on the tine, and which is movable through the soil so as to loosen the soil and to create a soil stream which is movable over the surface of the arrowhead formation, the tubular mounting portion presenting a narrow profile to the stream of soil through which it is movable so that in use it applies only small movement to the soil stream laterally outwardly of the shank; and wing flaps arranged on the arrowhead formation to exert a forward and part upward propelling movement to soil loosened by the arrowhead formation, said wind flaps also being shaped relative to the flat arrowhead format-on so as to apply laterally inward movement to the stream o soil and thereby to compensate for the outward movement applied to the soil stream by the tubular mounting portion of the shank and provide a substantially uniform flat-surfaced seed bed of worked soil.

The flat arrowhead formation is therefore able to carry out a soil-working action at a predetermined depth below the ground surface, and to move in a plane which is substantially parallel to the surface of the ground, and which can thereby create a substantially uniform seedbed of generally constant depth.

When the tip is mounted on a tine, the shank of the tip extends obliquely downwardly and forwardly of the lower end of the tine, and then merges into the flat arrowhead formation (which will be substantially horizontal when a horizontal ground surface is being worked). The shape of the tine is such that, when the tip meets resistance to forward movement through the ground, the tip can yield against resilient opposition provided by the tine and, in so doing, remains at generally the same level below the ground surface.

Preferably, this is achieved by suitable geometry in the design of the shape of the tine, so that rearward yielding movement of the tip is permitted, but which is taken-up by the resilient deformation of the tine in such a way that there is little, if any, vertical displacement of the tip.

The arrowhead formation preferably has upwardly extending flaps (similar to the flaps on the wings of an aircraft) which are arranged to exert a forward and part upward propelling movement to soil loosened by the arrowhead formation, and these flaps therefore generate turbulent motion in the soil particles which promotes the breaking- down of the soil and the formation of a satisfactory seedbed.

To provide rapid and reliable assembly, and disassembly, it is preferred that a single point fastening arrangement is provided to mount the shank of the tip on the lower end of the tine.

The tine is preferably of one-piece formation and having a general C-shape formed by an intermediate bend portion, a first portion extending upwardly and forwardly from the bend portion, and a second portion extending downwardly and forwardly of the bend portion, and in which a tine mounting portion is formed on the upper end of the first portion, and a tip-mounting portion is provided on the lower end of the second portion.

The tine mounting portion preferably includes at least one spring coil, to give resilience to the tine so as to provide resilient opposition to rearward displacement of the tip under load. The tip-mounting portion preferably comprises a seat which can fit non-rotatably within a hollow part of the shank of the tip, and to which it is preferably securable by a single fastener.

Thus, when the tine is mounted on the frame of an agricultural implement which is standing on level ground, the tip of the tine can be located at a predetermined depth below the ground surface with the flat arrowhead formation generally parallel to the ground surface, and by virtue of the shape of the tine, any rearward displacement of the tip under load does not result in any appreciable change in level of the arrowhead formation.

Preferably, the shank of the tip and the lower end of the tine are gently curved so as to merge smoothly into the flat arrowhead formation, and this shape assists in controlling any rearward displacement of the tip under load so as to maintain a generally constant depth.

In a preferred arrangement, the displacement of the tip is along a slightly curved path (as seen in side view), and with maximum depth of the arrowhead being reached when the tip has been rearwardly displaced under a predetermined load from its natural or rest position. Further rearward displacement then may cause slight upward displacement of the arrowhead formation, but at worst to no higher a level than the starting depth under no-load conditions.

The tine mounting portion preferably includes at least one spring coil, as referred to above, and may terminate in a suitable mounting end by which the tine can be mounted on the frame of an implement. The mounting end may comprise a generally U-shaped formation on the free end of the tine, located in a plane generally parallel to the plane of the arrowhead formation, and which can then be rigidly secured to a suitable mounting on the frame of the implement. The mounting may be directly onto a frame beam, or via a spacer, if it is desired to vary the depth of the tip of the tine relative to the frame.

A preferred embodiment of soil-working tip for an agricultural tine according to the invention will now be described in detail, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a perspective illustration of a known design of arrowhead formation of a tip for mounting on the lower end of an agricultural tine; Figure 2 is a perspective illustration of a preferred embodiment of soil-working tip according to the invention, mounted on the lower end of an agricultural tine; Figure 3 is a side view of the soil-working tip as shown in Figure 2; Figure 4 is a plan view corresponding to Figure 3; and Figures 5a, b and c are schematic plan view, front view and side view respectively and showing the working action applied to the soil by the tip shown in Figures 2 to 4.

Referring first to Figure 1 of the drawings, this shows a known design of soil-working tip 20 for mounting on the lower end of an agricultural tine (not shown), and which comprises a soil-working portion 21 which is shaped generally in the manner of a snow plough, having a forward lower pointed end 22, and at the rear end an obliquely upwardly extending shank or stub portion 23 shaped to seat on the lower end of a tine, and to which it can be secured by fastenings (not shown) taken through mounting apertures 24 and 25 in the stub 23.

The snowplough type formation 21 is generally triangular, as seen in plan view, but is formed by two diverging blades which extend rearwardly and outwardly of the forward pointed end 22, and in addition each blade is inwardly inclined to the vertical and in a direction towards the stub 23.

Evidently, this design of snowplough type formation is able to carry out a soil-working operation on soil below the ground surface, but this will tend to loosen the soil and then displace the soil laterally into two separate streams, lying one on either side of the forward pointed end 22.

Therefore, while this is acceptable for some soil-working operations, this will not generate the formation of a seedbed of substantially uniform depth, and not necessarily with required breaking-down of all of the soil constituents into approximately the same size soil fragments.

The above described known generally triangular shape tip (as seen in plan) is set-out by way of background to the following description of a preferred embodiment with reference to Figures 2 to 5.

A soil-working tip according to the invention is therefore shown generally by reference 30, and is intended to be mounted replaceably on the lower end 31 of an agricultural tine which is designated generally by reference 32. The tine 32 has a small circular cross-section, and therefore has a small lateral projection only relative to its forward movement through soil during operation. The tip 30 is generally triangular in shape, as seen in plan, and diverges from a pointed forward end 33.

The tip 30 comprises a substantially flat arrowhead formation 34 which is intended to be located in a plane substantially parallel to the surface of the soil to be worked, and in which the formation 34 defines the pointed forward end 33, and diverges therefrom.

An integral shank 35 projects obliquely upwardly and rearwardly of the arrowhead formation 34, with the shank 35 being integrally connected at its forward lower end to the arrowhead formation 34. The shank 35 also has a mounting portion 36a at its opposite end which is at least partly tubular so as to receive the lower end 31 of the tine 32 in order to mount the tip 30 on the tine 32.

The flat arrowhead formation 34 is therefore able to carry out a soil-working action at a predetermined depth below the ground surface, and to move in a plane which is substantially parallel to the surface of the ground, thereby to create a substantially uniform seedbed of generally constant depth, and generally similar sized broken down soil fragments.

When the tip 30 is mounted on the tine 32, the shank 35 of the tip extends obliquely downwardly and forwardly of the lower end 31 of the tine 32, and then merges into the flat arrowhead formation 34, which will be substantially horizontal when a horizontal ground surface is being worked.

The shape of the tine 32 is such that, when the tip 30 meets resistance to forward movements through the ground, the tip 30 can yield against resilient opposition provided by the tine 32 and, in so doing, remains at generally the same level below the ground surface.

This is achieved by suitable geometry in the design of the shape of the tine 32, so that relative rearward yielding movement of the tip 30 is permitted, but which is taken-up by the resilient deformation of the tine 32 in such a way that there is little, if any, vertical displacement of the tip 30.

The arrowhead formation 34 is provided with upwardly extending wing flaps 36 (similar to the flaps on the wing of a aircraft). which are arranged to exert a forward and part upward propelling movement to soil loosened by the arrowhead formation 34, and which generates turbulent motion in the soil particules which promotes the breaking-down of the soil and the formation of a satisfactory seedbed. However, as will be described in more detail below with reference to Figures 5a, b and c, the wing flaps 36 are also shaped so as to be capable of applying inwardly directed forces to the moving stream of soil particles loosened by the arrowhead tip formation 34.

To provide rapid and reliable assembly, and disassembly, a single point fastening arrangement is provided in order to mount the shank 35 on the lower end 31 of the tine 32. This is achieved by rigid seating of the tine end 31 within the correspondingly shaped tubular mounting portion 36a of shank 35, and which therefore allows a single fastener 37 to be utilised in order to provide a rigid assembly.

The tine 32 is of one-piece formation, having a general C-shape formed by a bend portion 38, a first portion 39 extending upwardly and forwardly from the bend portion 38, and a second portion 40 which extends downwardly and forwardly of the bend portion 38 to merge into the lower end 31. A tine mounting portion 41 is provided on the upper end of the first portion 39, and a tip-mounting portion (lower end 31) is provided on the lower end of the second portion 40.

The tine mounting portion 41 includes at least one spring coil 42, as shown, to give resilience to the tine so as to provide resilient opposition to rearward displacement of the tip 30 under load. The tip mounting portion (31) comprises a seat which fits non-rotatably within the hollow mounting portion 36a of the shank 35 or the tip 30, and is secured by single fastener 37.

When the tine 32 is mounted on a frame of an agricultural implement which is standing on level ground, the tip 30 will be located at a predetermined depth below the ground surface with the flat arrowhead formation 34 generally parallel to the ground surface, and by virtue of the shape of the tine 32, any rearward displacement of the tip 30 under load does not result in any appreciable change in level of the arrowhead formation 34.

The shank 35 of the tip 30 and the lower end 31 of the tine 32 are gently curved so as to merge smoothly into the flat arrowhead formation 34, and this shape assist in controlling any rearward displacement of the tip 30 under load so as to maintain a generally constant depth.

Figure 2 is only a perspective illustration, but if viewed from the side, the arrowhead formation 34 will be located forwardly of the spring coil 32, and the geometry of the assembly is such that, when the tip 30 is displaced rearwardly under load, it will follow a slightly curved path, as seen in side view. The maximum depth of the arrowhead 34 will be reached when the tip 30 has been cearwardly displaced under a predetermined load from its natural or rest position. Further rearward displacement of the tip may then cause slight upward displacement of the arrowhead formation, but at worst to generally the same level, or not appreciably higher level than the starting depth under the no-load conditions.

In order to mount the tine 32 (plus its soil-working tip 30) on the frame of an agricultural implement, the spring coil formation 42 terminates in a U-shaped end 43, which is located in generally the same plane as the flat arrowhead formation 34, and which is capable of being rigidly secured to any suitable mounting point on the frame of the implement. This may be a direct mounting on a suitable rigid mounting point on the frame, or through the intermediary of a vertical spacer, if depth adjustment of the tine is required.

The above description of the preferred embodiment has been in relation to the construction of soil-working tip 30 to be mounted on the lower end of a tine 32 of an agricultural implement, as shown in Figure 2. Figures 3 and 4 show, respectively, a side view, and a plan view of the embodiment of soil-working tip as shown in Figure 2.

Figures 5a, b and c show, respectively, a plan view, front view, and side view, with schematic illustration of the movement of soil loosened by the soil working tip 30, as it moves through the soil below the level of the ground surface thereof.

In particular, Figure 5 shows a soil stream, designated generally by reference 38, which is loosened by forward movement of the arrowhead formation 34 through the ground, below the surface thereof, and which shows how this stream 38 of loosened soil is caused to move. In particular, the tubular portion 36a of the shank 35, (being of tubular shape so as to receive the circular cross-section of the lower end 31 of the tine 32), presents a relatively narrow profile to the stream of soil 38 through which it is movable, so that in use it applies only small movement to the sol-stream laterally outwardly of the shank 35, as shown by reference 38a in Figure 5a.

However, the construction and arrangement c~ the wing flaps 36, arranged on the trailing end of the arrowhead formation 34, is such as to exert a forward and part upward propelling movement to the soil loosened by the arrowhead formation 34 (see the shape of the flaps 36 in the side profiles shown in Figure 3 or Figure 5c). However, in addition the profile of the wing flaps (as seen in frontal end view of Figure 5b) are also shaped relative to the flat arrowhead formation so as to apply laterally inward movement to the stream of soil and thereby to compensate for the outward movement applied to the soil stream by the tubular mounting portion 36a of the shank and provide a substantially uniform flat-surfaced seedbed of worked soil.

This can be seen quite clearly from the schematic illustration in Figure 5a. Thus, the relatively narrow transverse profile presented by the tubular portion 36a of the shank 35, means that only a small laterally outward force is applied to the moving stream 38 of loosened soil (see outwardly deflected path 38a), but in any event the shape and arrangement of the flaps 36 is such as to compensate for such lateral outward displacement 38a of the soil stream, in that the wing flaps 36 apply a slightly inward deflection to the soil stream, as can be seen by reference 38b in Figure 5a. This compensates for the laterally outward deformation of the soil stream 38a by the tubular portion 35a, and which results in the creation of a substantially uniform flat-surface seedbed of worked soil, behind the soil working tip, as shown generally by reference 39.

Figure 5b is a frontal view of the soil working tip, and which illustrates schematically how it is only the soil above and over the whole width of the tip 30 which is lifted and then worked-upon. The soil 40, on either side of the working tool 30, remains substantially unaffected. This figure also shows how the height of the swing flats 56 (above the general plane of the flat arrow-head formation 34) increases in a direction laterally outwardly of the shank.

This upwardly and outwardly curving profile, shown by reference 36a, is therefore able to form the compensating rearward and inwardly directed soil stream 38b.

Figure 5c is a side view, in schematic illustration, showing how the soil stream 38 is lifted as it flows over the arrowhead formation 34 of the tip, and which then falls under gravity to a level generally in line with the level of the soil initially penetrated by the tip 33 of the arrowhead formation 34.

The illustration in Figures 5a, b and c is somewhat simplified, and in practice the flow of the loosened stream of soil is somewhat turbulent, although the main portion of the flow of soil is generally as described and illustrated.

However, the turbulence which is imparted to the flow of soil brings about a mixing action to the soil components, and the end result is a substantially even soil surface after completion of the working operation, and subsequent discharge rearwardly of the soil working tool.