AU2017232189A1 - A shank and blade arrangement - Google Patents

Abstract

Abstract This disclosure relates to a shank and blade arrangement for agricultural equipment such as a plough, and separately a shank and a plough blade. According to a first aspect, disclosed is a shank and plough blade arrangement comprising a shank having an external profile comprising one or more outwardly extending flanges, each flange defining a shoulder; and a plough blade extending between a leading end and a trailing end and having an internal cavity extending inwardly from the trailing end, the internal cavity having an internal surface corresponding generally to the external profile of the shank, a portion of the internal surface comprising an abutment surface, wherein in use the shank is inserted into the internal cavity of the blade, and the abutment surface and the shoulder are configured such that the abutment surface abuts the shoulder of the shank to inhibit movement of the trailing end of the blade relative to the shank in response to forces on the leading end of the blade. 0 -i mm

Description

A SHANK AND BLADE ARRANGEMENT Technical Field

This disclosure relates to a shank and blade arrangement for agricultural equipment such as a plough, and separately a shank and a plough blade.

Background Art

Ploughs used for the cultivation of soil, typically include multiple attached shanks extending from shanks used to upturn the soil. Known blades are attached to the shanks via roll pins, or interference fit and replaced when they wear out. In these arrangements, when the plough is in use, the blade is lifting the soil causing it to crack and aerate. The blade is under extreme force being pressed back on to the shank and has some give in the arrangement which allows for some movement. This force and movement during use on between the blade and the shank results in wear in the attachment between the blade and the shank.

Existing blades and attachments commonly secure around an entire feature of the shank covering the bottom surface and using this bottom surface as a securing point. The primary wear surfaces are the forward facing, ground engaging features which till the soil. Secondary wear takes place on the underside and sides of the assembly. This secondary wear, specifically the wear on the underside of the assembly often goes unseen causing damage to the underside of the shank, eventually destroying the shank’s features which secure the blade resulting inthe need to replace the shank.

It is to be understood that, if any prior art is referred to herein, such reference does not constitute an admission that the prior art forms a part of the common general knowledge in the art, in Australia or any other country.

Summary

According to a first aspect, disclosed is a shank and plough blade arrangement comprising a shank having an external profile comprising one or more outwardly extending flanges, each flange defining a shoulder; and a plough blade extending between a leading end and a trailing end and having an internal cavity extending inwardly from the trailing end, the internal cavity having an internal surface corresponding generally to the external profile of the shank, a portion of the internal surface comprising an abutment surface, wherein in use the shank is inserted into the internal cavity of the blade, and the abutment surface and the shoulder are configured such that the abutment surface abuts the shoulder of the shank to inhibit movement of the trailing end of the blade relative to the shank in response to forces on the leading end of the blade.

Advantageously, the shank and plough blade arrangement reduces wear on the components to increase the time between replacing the components. In particular, the contact surfaces being the shoulder and the abutment surface being positioned on the sides of the shank (as opposed to the bottom surface in known blade and shank attachments) is substantially stronger and able to secure greater force during operation. The shape of the internal cavity including the abutment surface defines a blade securing portion of the blade which is formed between the abutment surface and a bottom surface. In use this blade securing portion acts to secure the blade from over-pivoting. In some embodiments, the dimensions and/or material of the blade securing portion determine the strength of the blade and the shank arrangement in regard to its ability to endure force pivoting the blade forward and down. Moreover, this increases the longevity of the shank against the wear to the underside of the shank. The point of contact being on the sides of the arrangement (in the form of the two flanges and the blade securing portions) allows wear to occur to the underside of the shank without effect to the blades attachment increasing the shanks working life.

In some forms, the blade securing portion is substantially square or rectangular being shaped such that the thickness of the portion is approximately half the length, however, it is understood that the blade securing portion may vary in dimension and shape. In some forms, the blade is formed from steel, and in particular blade material steel, specifically 8630 alloy steel, but it is understood that other materials may be used, and in particular, other kinds of steel may be used.

In addition, the blade is easy to couple to the shank for an individual. The blade simply slides onto the shank and may be secured with a retaining member.

In the context of the specification, it is understood that, the term blade may be interchangeable with point and the term shank may be interchangeable with tyne or tine.

In some embodiments, in use the shoulder of the shank and the abutment surface of the plough blade are configured such that in use the shoulder faces generally downwards, and the corresponding abutment surface of the plough blade faces generally upwards to abut the shoulder. In some embodiments, the configuration of the external profile of the shank corresponding to the internal profile of the plough blade inhibits pivotal movement of the blade in relation to the shank in use. Some pivoting of the blade in relation to the shank is allowed to provide some give to the arrangement, but the shoulder and the corresponding abutment surface prevent over-rotational movement which would increase wear on the components and prevent over-rotational movement which changes the angle of the blades action against the soil and reduce its effectiveness.

In some embodiments, the shank extends between a toe and a heel, and the one or more flanges are positioned proximal to the heel of the shank. In some embodiments, the shank further comprises a retaining member extending from the shank to retain the blade with respect to the shank and the plough blade further comprises one or more cut-outs positioned such that the retaining member is configured to fit within a respective cut-out.

In some embodiments, each cut-out further comprises an abutment edge positioned such that when the arrangement, the blade or the shank are not in use the abutment edge of each cut-out and an associated abutment of the retaining member abut one another to inhibit the blade from being released from the shank. In some embodiments, when the arrangement is in use, the blade does not contact the retaining member.

According to a second aspect, disclosed is a plough blade arranged to be coupled to a shank extending from a plough, the plough blade extending between a leading end and a trailing end, and having an internal cavity extending inwardly from the trailing end, the internal cavity having an internal surface corresponding to an external profile of the shank, a portion of the internal surface comprising an abutment surface, wherein in use the shank is inserted into the internal cavity of the blade and the abutment surface is configured such that it abuts a shoulder of the shank to inhibit movement of the trailing end of the blade relative to the shank in response to forces on the leading end.

In some embodiments, the abutment surface is configured such that in use it faces generally upwardly.

In some embodiments, a blade securing portion of the blade is formed between the abutment surface and a bottom surface. In use this blade securing portion acts to secure the blade from over-pivoting. In some embodiments, the dimensions and/or material of the blade securing portion determine the strength of the blade and the shank arrangement in regard to its ability to endure force pivoting the blade forward and down.

In some forms, the blade securing portion is substantially square or rectangular being shaped such that the thickness of the portion is approximately half the length, however, it is understood that the blade securing portion may vary in dimension and shape.

In some forms, the blade is formed from steel, and in particular blade material steel, specifically 8630 alloy steel, but it is understood that other materials may be used, and in particular, other kinds of steel may be used.

According to a third aspect, disclosed is a shank extending from an agricultural plough arranged to receive a plough blade, the shank comprising a body extending between a toe and a heel, and having an external profile comprising one or more flanges extending outwardly from the body, each flange defining a shoulder, the external profile corresponding to an internal profile of the plough blade, wherein, in use, the shank is inserted into the internal cavity of the blade and the shoulder is configured such that an abutment surface of the blade abuts the shoulder of the shank to inhibit movement of the blade relative to the shank at the heel in response to forces of the blade at the toe of the shank.

In some embodiments, the shoulder of the shank is configured such that in use the shoulder faces generally downwards.

In some embodiments, the shank extends between a toe and a heel, and the one or more flanges are positioned proximal to the heel of the shank.

In some embodiments, the shank is formed from steel, but it is understood that the shank may be formed from many different types of steel and other suitable materials.

Brief Description of the Drawings

Embodiments will now be described by way of example only, with reference to the accompanying drawings in which

Fig. 1 is a perspective view of an embodiment of a shank;

Fig. 2 is side view of an embodiment of a plough blade;

Fig. 3 is a cross-sectional view of the plough blade of Fig. 2;

Fig. 4 is an end cross-sectional view of the blade of Fig. 2;

Fig. 5 is a cross-sectional view further towards the leading end of the blade of Fig. 2 as compared to Fig. 4;

Fig. 6 is a side view of an embodiment of the blade of Fig. 2 coupled to the shank of Fig. 1 when in use;

Fig. 7 is a cross-sectional view of the blade coupled to the shank of Fig. 6;

Fig. 8 is a side view of the blade coupled to the shank of Fig. 6 when not in use;

Fig. 9 is a side view of the blade coupled to the shank of Fig. 8 showing some of the shank cut away; and

Fig. 10 is a side view of an embodiment of a plough beam including an embodiment of a shank and plough blade arrangement;

Detailed Description

In the following detailed description, reference is made to accompanying drawings which form a part of the detailed description. The illustrative embodiments described in the detailed description, depicted in the drawings and defined in the claims, are not intended to be limiting. Other embodiments may be utilised and other changes may be made without departing from the spirit or scope of the subject matter presented. It will be readily understood that the aspects of the present disclosure, as generally described herein and illustrated in the drawings can be arranged, substituted, combined, separated and designed in a wide variety of different configurations, all of which are contemplated in this disclosure.

Disclosed is a shank and plough blade arrangement 1 for a plough 14 to upturn soil. The arrangement 1 comprises a shank 10 and a blade 12. The blade 12 is removable from the shank 10 of the plough 14 as occasionally the blade 12 will wear and need to be replaced or one of the components will need to be repaired.

The arrangement is configured to inhibit wear between the shank 12 and blade 10 arrangement.

Now turning to Figs. 1 through 5, the shank 10 includes an external profile comprising one or more outwardly extending flanges 16, each flange defining a shoulder 18. The plough blade 12 extends between a leading end 20 and a trailing end 22 and has an internal cavity 24 extending inwardly from the trailing end 22. The internal cavity 24 has an internal surface 26 corresponding generally to the external profile of the shank 10, and a portion of the internal surface 26 comprising an abutment surface 28. In use the shank 10 is inserted into the internal cavity 24 of the blade 12. The abutment surface 28 and the shoulder 18 are configured such that the abutment surface 28 abuts the shoulder 18 of the shank 10 to inhibit movement of the trailing end 22 of the blade 12 relative to the shank 10 in response to forces F on the leading end 20 of the blade 12.

The disclosed shank 10 and blade 12 arrangement is advantageous as it increases time between replacements and repair for both the shank 10 and the blade 12 components. When the plough 14 is working, the blade 12 forces the soil above it upward and forward. As such the blade 12 is movably coupled to the shank 10 to accommodate the blade 12 pivoting in relation to the shank 10. However, the degree of the pivoting movement is limited otherwise there is wear on portions of the internal surface 26 of the internal cavity 26 of the blade 12 and portions of the shank 10. The shank 10 is not as easily replaceable or repairable as the blade 12 and thus much more expensive to replace. In particular, the point of contact between the shank 10 and the blade 12 being at the sides of the arrangement allows wear to occur to the underside of the shank 10 without effect to the coupling between the blade 12 and shank 10 arrangement, thus increasing the working life of the arrangement.

In the illustrated embodiment, disclosed are two flanges 16 that are designed to limit the pivoting movement of the blade 12 in relation to the shank 10. The flanges 16 may also retain the blade 12 in relation to the shank 10. Each flange 16 is also wedge-shaped and positioned proximal to the heel 36 towards a top portion of the shank 10. In the illustrated embodiment, the angle of the wedge-shaped shank 10 is 20 degrees, and the angle of the wedge-shaped flanges 16 are each 20 degrees. In alternative embodiments, the angle of the wedge-shaped shank may differ from the angle of the wedge-shaped flange in the range of 10 degrees to 40 degrees, 10 degrees to 60 degrees or even 10 degrees to 85 degrees. In the illustrated embodiment the width of the shank 10 at the bottom is 30mm and the width of shank 10 with the side flanges 16 is 47mm.

Each flange 16 defines a shoulder 18. The shoulder 18 generally faces downwards in use to contact the corresponding abutment surface 28 of the blade. The position of each flange 16 and the shoulder 18 is advantageous in operation to effectively inhibit pivoting of the blade 12 in relation to the shank 10. The position of each flange 16 is optimal because the upwards force on the heel 36 of the shank 10 is the largest force. The direction of the shoulder 18 is generally opposite to the force being exerted by the blade 12 to inhibit the blade 12 from over-pivoting. Reducing the relative movement between the shank 10 and the blade 12 reduces the wear between the contact surfaces, such as the shoulder 18 and the abutment surface 28.

The size of each flange 16 is designed to allow a small range pivoting movement between the shank 10 and the blade 12 and avoid fastening the components 10, 12 together, for example an interference fit, or allowing a large range of pivoting movement between the shank 10 and the blade 12. In addition, the shoulder 18 is in the form of a planar surface having an area that is designed to maintain a large surface area of contact between the abutment surface of the blade and the shoulder 18 and spread the forces being transferred from the blade. In alternative embodiments, the shoulder may be ridged or undulating and is not required to be planar.

Although in the illustrated embodiment the flanges 16 are symmetric, each flange 16 is not required to be a symmetric and may be used for different functions, for example, one flange may be used to retain the blade in relation to the shank and the other may be used to inhibit pivoting of the blade in relation to the shank.

Other surfaces of the shank in contact with the internal cavity of the blade are a toe surface 38 positioned at the toe 34. Downward forces on the point of the blade 12 result in downward forces on the toe surface 38. There is little relative movement at the toe 34 between the shank 10 and the blade 12 because of the external profile of the shank 10 at the toe 34 and the corresponding internal profile of the internal cavity 24 of the blade 12.

The shank 10 further comprises a retaining member 40 extending from the shank 10 to retain the blade 12 with respect to the shank 10. In the illustrated embodiment, the retaining member 40 is in the form of a roll pin 40 that extends through the shank 10 and projects outwardly from either side of the shank 10.

The retaining member 40 includes an associated abutment portion 42 on either side of the shank 10. The blade 12 is configured to fit around the retaining member 40, such that in use there is no contact between the blade 12 and the abutment portions 42. The abutment portions 42 inhibit the blade 12 from being released from the shank 10 and thus retain the blade 12 in relation to the shank 10 in particular orientations.

In non-illustrated alternative embodiments, the retaining member 40 may be any shape and may be in the form of multiple retaining members inserted on either side of the shank, or the retaining member may be in the form of a clip which clips onto the blade and into a recess in the shank.

Figs. 2 to 5 illustrate the blade 12 in detail. The blade 12 is removable from the shank 10 to be easily replaced. With use and over time, the point and sharp edges will dull and lose their effectiveness for overturning soil.

As mentioned above, the blade 12 extends between the leading end 20 and the trailing end 22. The leading end 22 forms the point or tip of the blade which is designed to cut the soil in use. In general, the blade 12 is wedge-shaped, and has a topside exterior 44 that is designed to move the soil upward and forward along and around the blade. In the illustrated embodiment, the exterior of the blade includes four ridges 46 with troughs 48 extending between the ridges 46. This uneven exterior surface 44 reduces wear by capturing soil and uses the captured dirt as a wear medium. The upper surface and ground engaging face of the blade could be sculpted differently, be smooth, convex or concave, rippled or waved.

An underside exterior 50 of the blade is generally flat configured to slide along the ground so as to not interfere with the forward movement of the plough 14. A portion of the underside of the blade is not enclosed and includes one or more cutouts 52. In the illustrated embodiment, there are two cut-outs 52 positioned such that each retaining member 40 is configured to fit within a respective cut-out 52. Each cut-out 52 may be any shape and does not need to enclose the respective retaining member 40. Each cut-out 52 includes an abutment edge 54 which contacts a portion of the retaining member 40 when not in use to inhibit the blade from being released from the shank. The abutment edge 54 faces the leading end 50 of the blade. In the illustrated form the cut out 52 is located in the underside exterior and extends around a substantial portion of the blade to remove a side portion of the blade. The abutment edge is positioned at the side wall of the blade.

The blade 12 includes the internal cavity 24 extending inwardly from the trailing end 22. The internal cavity 24 has the internal surface 26 that corresponds to the external profile of the shank 10. The toe 34 of the shank 10 fits in the innermost portion of the internal cavity 24. A portion of the internal surface 24 includes the abutment surfaces 28, which are configured to abut the shoulder 18 of the shank 10 to inhibit movement of the trailing end 22 of the blade relative to the shank in response to forces on the leading end 20.

In the illustrated embodiment, there are two abutment surfaces 28 corresponding to the respective shoulders 18 on the flanges 16 of the shank 10. The abutment surfaces 28 are configured such that in use each face generally upwardly, which is generally opposite the direction of that the shoulder 18 faces. The shape of the internal cavity 26 including the abutment surface 28 defines a blade securing portion 31 of the blade 12 which is formed between the abutment surface 28 and a bottom surface 29. In use this blade securing portion 31 acts to secure the blade from over-pivoting. In particular, the thickness of the material between each abutment surface 28 and a bottom surface of the blade 29 is sufficient to endure force during operation. In alternative embodiments, the blade securing portions and the abutment surfaces may be any shape, size and/or length.

In the illustrated embodiment, the blade securing portion 31 is approximately 30 mm in length (e.g., the dimension between the abutment surface 28 and the bottom surface 29), approximately 25 mm in width (e.g., the dimension between the cut-out 52 and an end surface of the blade), the bottom surface 29 of the blade securing portion 31 is approximately 12mm in thickness (as best shown in the end view Fig. 4), and the abutment surface of the blade securing portion is approximately 8 mm in thickness (as best shown in the end view Fig. 4. In alternative non-illustrated embodiments, the blade securing portion may be any size or shape provided it acts to secure the blade from over-pivoting.

Thus the overall dimensions of the blade securing portion 31 are in an approximate ratio of length to width to thickness of 1:1:0.5. It is understood that this ratio can be varied, for example the length to width to thickness may be between 2:1:0.5 and 1:2:0.5 or alternatively between 35:20:12 and 25:25:12. The thickness may vary from between a quarter of the length to two thirds of the length.

Figs. 4 and 5 are cross-sections of the blade through different planes. Fig. 4 is a cross-section of the trailing end 22 of the blade 12, and Fig. 5 is a cross-section of a plane of the blade 12 between the trailing end 22 and the leading end 20 through the cut-outs 52. The profile of the blade 12 and the shank 10 tapers toward the point so the profile changes shape depending on the cross-section taken through the arrangement. The profile of both of the cross-sections shown corresponds to the shape of the shank 10 which is generally T-shaped at and towards the trailing end 22.

In the illustrated embodiment, a top portion of the internal cavity 24 extends from top bar of the T-shape is a shin guard cavity 26. Thus, the overall profile of both cross-sections in the illustrated embodiment is generally cross-shaped. The blade 12 is also able to secure a shin guard 58 which extends along the front portion of the shank to protect the shank of the plough 14 during use. However, the shin guard cavity 58 is not required.

In Figs. 6 to 9, the shank 10 and blade 12 arrangement is illustrated where the blade 12 is coupled to the shank 10.

First, referring to Figs. 6 and 7 which show the arrangement when plough 14 is in use. When the plough 14 is working the blade 12 drives forward which forces the soil above it, upward and forward. The resultant force on the blade 12 tips the leading end 20 of the blade 12 downwards. The blade 12 and the shank 10 are configured so that the abutment surfaces 28 of the blade 12 abut (and catch) on the respective side flanges 16 of the shank 10 to inhibit the downward pivoting of the leading end 20 of the blade 12. The innermost portion of the internal cavity 24 of the blade 12 is also in contact with the toe 34 of the shank 10 during the pivoting movement of the blade in relation to the shank. The side flanges 16 secure the leading end 20 of the blade 12 from tipping forward without requiring the blade 12 to enclose the bottom of the shank 10.

Existing blades and attachments commonly secure around an entire feature of the shank covering the bottom surface and using this bottom surface as a securing point. This bottom surface forms the abutment surfaces which stop the blade tilting forward. The illustrated shank and blade arrangement moves this point of contact away from the underside of the shank. This has at least the following two advantages:

Firstly, the underside of existing blades is commonly the thinnest feature of the blade and thus one of the weaker areas. The illustrated blade 12 and shank 10 attachment having the shoulder and abutment surface positioned on the sides of the shank allows for much greater thickness of material, for example the blade securing portion 31, in the blade 12 under the abutment surface 28. Asa result, the shank 10 and blade 12 arrangement is substantially stronger than existing arrangements and able to secure greater force during operation.

Secondly, this increases the longevity of the shank 10 against the wear to the underside of the shank 10. There are no securing features near the underside of the shank and all securing features are under the working surface of the blade, thus clear of wear. Moving the point of contact up (in the form of the two flanges and corresponding blade securing portions) allows wear to occur to the underside of the shank without effecting the blade’s attachment to the shank and thus increasing the shank’s working life.

Further, the shank 10 includes the retaining member 40 which fits within the cutouts 52 of the blade 12. When the arrangement is in use, the cut-out 52 of the blade 12 does not contact either side of the retaining member 40 extending outwardly from the shank 10. In other words, there is a clear gap G between each cut-out 52 of the blade 12 and the respective portion of the retaining member 40. The forward movement of the plough 14 forces the blade 12 toward the trailing end 22 which creates and maintains this gap G. As a result, the retaining member 40 is not under load during forward motion. Advantageous, the retaining member 40 not being under load during use avoids the risk of deformation to the retaining member, making it hard to remove and replace the blade 12.

Second, referring to Figs. 8 and 9 which show the arrangement when plough 14 is not in use. When the plough 14 is not working or in the event that the 14 plough is forced backward the blade 12 slides forward and comes into contact with the retaining member 40 to inhibit the blade 12 from being released from the shank 10. In the illustrated embodiment, the abutment edge 54 of the cut-out 52 comes into contact with the associated abutment portions 42 of the retaining member 40. The abutment edge 54 is a corresponding shape to the abutment portion 42, but it is understood that the abutment portions are not required to be a corresponding shape to the abutment edge of the cut-out.

Further, the shoulder 18 located on each side flange 16 also comes into contact with the abutment surface 28 of the internal cavity 24 of the shank 10 (as best shown in Fig. 9 which is a partial section view having some of the blade cut away). As a result, the profile of the internal cavity 24 is wedged between the abutment edges 54 of the retaining member 40 and the shoulders 18 of the side flanges 16. Therefore, the blade 12 is retained in relation to the shank 10.

Fig. 10 illustrates the shank 10 and blade 12 arrangement in context extending from an embodiment of a frame of a plough 14. In order to couple the blade 12 to the shank 10, the shank 10 is inserted into the internal cavity 24 of the blade 12 and then the retaining member 40 is inserted into the shank 10 to retain the shank 10 in relation to the blade 12. In order to replace or repair the blade 12, the opposite steps are taken. The retaining member 40 is removed from the shank 10, and then the blade 12 is decoupled from the shank 10. In the illustrated embodiment, the blade 12 is secured with a 12mm diameter retaining member, but the size may vary anywhere between 8 and 14 mm. The length of the retaining member is less than the width of the blade so the retaining member is not exposed to direct wear from the earth, but the length is long enough that the retaining member contacts both sides of the blade.

While a particular blade shape is shown, any blade shape may be utilised in the system.

Variations and modifications may be made to the parts previously described without departing from the spirit or ambit of the disclosure. For example, the shank and blade arrangement made be used on any frame for any plough.

In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word “comprise” or variations such as “comprises” or “comprising” is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

Claims (12)

1. Claims

   1. A shank and plough blade arrangement comprising : a shank having an external profile comprising one or more outwardly extending flanges, each flange defining a shoulder; and a plough blade extending between a leading end and a trailing end and having an internal cavity extending inwardly from the trailing end, the internal cavity having an internal surface corresponding generally to the external profile of the shank, and part of the internal surface includes an abutment surface, wherein in use the shank is inserted into the internal cavity of the blade, and the abutment surface and the shoulder are configured such that the abutment surface abuts the shoulder of the shank to inhibit movement of the trailing end of the blade relative to the shank in response to forces on the leading end of the blade.
2. 2. A shank and plough blade arrangement as defined in claim 1, wherein in use the shoulder of the shank and the abutment surface of the plough blade are configured such that in use the shoulder faces generally downwards, and the corresponding abutment surface of the plough blade faces generally upwards to abut the shoulder.
3. 3. A shank and plough blade arrangement as defined in claim 1 or 2, wherein the shank extends between a toe and a heel, and the one or more flanges are positioned proximal to the heel of the shank.
4. 4. A shank and plough blade arrangement as defined in any one of the preceding claims, wherein the configuration of the external profile of the shank generally corresponding to the internal profile of the plough blade inhibits pivotal movement of the blade in relation to the shank in use.
5. 5. A shank and plough blade arrangement as defined in any one of the preceding claims, wherein the shank further comprises a retaining member extending from the shank to retain the blade with respect to the shank and the plough blade further comprises one or more cut-outs positioned such that the retaining member is configured to fit within a respective cut-out.
6. 6. A shank and plough blade arrangement as defined in claim 5, wherein each cut-out further comprises an abutment edge positioned such that when the arrangement is not in use, the abutment edge of each cut-out and an associated abutment portion of the retaining member abut one another to inhibit the blade from being released from the shank.
7. 7. A shank and plough blade arrangement as defined in claim 5 or 6, wherein when the arrangement is in use, the blade does not contact the retaining member.
8. 8. A plough blade arranged to be coupled to a shank extending from a plough, the plough blade extending between a leading end and a trailing end, and having an internal cavity extending inwardly from the trailing end, the internal cavity having an internal surface corresponding to an external profile of the shank, a portion of the internal surface comprising an abutment surface, wherein in use the shank is inserted into the internal cavity of the blade and the abutment surface is configured such that it abuts a shoulder of the shank to inhibit movement of the trailing end of the blade relative to the shank in response to forces on the leading end.
9. 9. A plough blade as defined in claim 8, wherein the abutment surface is configured such that in use it faces generally upwardly.
10. 10. A shank extending from an agricultural plough arranged to receive a plough blade, the shank comprising: a body extending between a toe and a heel, and having an external profile comprising one or more flanges extending outwardly from the body, each flange defining a shoulder, the external profile corresponding to an internal profile of the plough blade, wherein, in use, the shank is inserted into the internal cavity of the blade and the shoulder is configured such that an abutment surface of the blade abuts the shoulder of the shank to inhibit movement of the blade relative to the shank at the heel in response to forces of the blade at the toe of the shank.
11. 11. A shank according to claim 10, wherein the shoulder of the shank is configured such that in use the shoulder faces generally downwards.
12. 12. A shank as defined in claim 10 or 11, wherein the shank extends between a toe and a heel, and the one or more flanges are positioned proximal to the heel of the shank.