Plow steel for a snow plow

Abstract

Add-on plow steel (100) for a snow plow, comprising: a fastening means (110) for mounting the plow steel (100) to a main plow steel (200) into a mounted state; and a main steel support plate (120), having a generally elongated shape. The main steel support plate (120) comprises a surface contacting edge (130), in turn com- prising a surface contacting insert (140) made of a wear-resistant material. The add-on plow steel (100) comprises two protrusions (150, 160) extending from the main steel support plate (120). The fastening means (110) is arranged on both the protrusions (150, 160) outside of the main steel support plate (120). A cross-section of the add-on plow steel (100) occupies at the most 75% of an area of a minimal rectangle, the minimal rectangle being defined as the smallest possible rectangle inscribing both the main steel support plate (120) and the protrusions (150, 160).

Description

[0001] Plow steel for a snow plow

[0002] The present invention relates to a plow steel for a snow plow. In particular, the present invention relates to a detachable and replaceable plow steel of the said type comprising a wear part.

[0003] Motor-driven snow plows are conventionally used for clearing paved streets and other hard surfaces from snow and ice. By scraping a plow blade across the surface, snow and ice is removed from the surface and can be pushed to the side of a road; collected for evacuation; or handled in any other desired way.

[0004] A plow blade is used as the point of contact with the hard surface across which it is scraped and is therefore subjected to extensive wear during use. The hard surface may be made from asphalt, concrete, gravel and so forth, and may have sand or other granular abrasive and / or friction-increasing material already on it at the time of snow plowing.

[0005] Many times, a layer of ice and / or compacted snow is present on the hard surface, which the plow blade needs to be able to penetrate and remove. Often, it is desired to plow a surface, such as a road, at relatively high velocities, while still being able to remove snow and ice sufficiently so as not having to pass several times.

[0006] To sum up, in order to perform adequately, the plow blade needs to be able to withstand heavy wear for prolonged periods of time. Plow blades need replacement after certain use, which is not only expensive in terms of replacement blades, but also poses logistic and plan- ning challenges.

[0007] In order to prolong the useful life of such plow blades, metal wear surfaces are used, that may also be configured with inserts of abrasive-resistant material such as tungsten carbine. Such plow blades, with a metal wear surface, are herein denoted "plow steels". Such a plow steel may also be used as a detachable and replaceable wear part on a larger plow blade. The wear of a plow blade is determined by a number of factors, such as the abrasiveness of the plowed surface and the friction between the plowed surface and the wear surface; the plowing velocity; the ice conditions; and so forth. The present invention solves the problem of prolonging the useful life of a plow blade.

[0008] Hence, the invention relates to an add-on plow steel for a snow plow.

[0009] The add-on plow steel can comprise a fastening means for mounting the plow steel to a main plow steel of the snow plow into a mounted state in which the add-on plow steel is in an upright orientation.

[0010] The add-on plow steel can comprise a main steel support plate, with a main plane extending across a width dimension and a height dimension, the width dimension being horizontal and the height dimension being vertical when the add-on plow steel is in the upright orientation.

[0011] The main steel support plate can have a generally elongated shape extending in the width dimension.

[0012] The main steel support plate can comprise a surface contacting edge, running along the width dimension along the main steel support plate and arranged to contact the ground when the add-on plow steel is in the mounted state and the snow plow is configured for plowing operation, the surface contacting edge comprising a surface contacting insert made of a wear-resistant material with better abrasive resistance than the main steel material of said steel support plate.

[0013] The add-on plow steel can comprise two protrusions extending in the height dimension from the main steel support plate away from the surface contacting edge. The fastening means can be arranged on both the protrusions outside of the main steel support plate.

[0014] A cross-section in the main plane of the add-on plow steel can occupy at the most 75% of an area of a minimal rectangle, the minimal rectangle being defined in the main plane as the smallest possible rectangle so that both the main steel support plate and the protrusions are inscribed in the minimal rectangle.

[0015] In some embodiments, the add-on plow steel comprises exactly two of the protrusions.

[0016] In some embodiments, the fastening means comprises a respective through hole through each of the protrusions, the through holes being aligned with corresponding fastening means of the main plow steel when the add-on plow steel is in the mounted state, the corresponding fastening means possibly also being through holes.

[0017] In some embodiments, each of the protrusions has a height-dimension end point in the mounted state of the add-on plow steel, which end point is at the same height or higher as compared to a height-dimension end point of the main steel support plate. In some embodiments, each of the protrusions has a width, in the width dimension, that is at least as large as a height, in the height dimension, of the protrusion.

[0018] In some embodiments, a connection between each of the protrusions and the main steel support plate is smoothly curved, with a radius of curvature of at least 10% of the height, in the height dimension, of the protrusion.

[0019] In some embodiments, the main steel support plate extends, in the width dimension, on both or either ends of the main steel support plate, beyond the protrusions. In some embodiments, the add-on plow steel has a non-flat shape, as viewed in a crosssection perpendicular to the width dimension, that is complementary to a corresponding shape of the main plow steel when the add-on plow steel is in the mounted state. In the following, the invention will be described in detail, with reference to exemplifying embodiments of the invention and to the enclosed drawings, wherein:

[0020] Figure 1 is a perspective view showing a main plow steel and a add-on plow steel mounted on the main plow steel in an upright orientation; Figure 2 corresponds to Figure 1, but shows the add-on plow steel mounted on the main plow steel in a different position along the main plow steel;

[0021] Figure 3 corresponds to Figure 1, but is shown in a front plan view;

[0022] Figure 4 corresponds to Figure 3, but also shows a minimum rectangle;

[0023] Figure 5 corresponds to Figure 1, but shown in a side plan view; Figure 6 corresponds to Figure 1, but is shown in a perspective section view;

[0024] Figure 7 is a perspective view of the add-on plow steel shown in Figure 1;

[0025] Figure 8 corresponds to Figure 7, but shown in a front plan view;

[0026] Figure 9 corresponds to Figure 8, but also shows the minimum rectangle;

[0027] Figure 10 is a perspective view of the add-on plow steel shown in Figure 7; and Figure 11 is a perspective section view of the add-on plow steel shown in Figure.

[0028] All Figures share the same reference numerals for same or corresponding parts.

[0029] An add-on plow steel 100 is arranged for use with a snow plow (the snow plow itself is not shown in the Figures). The add-on plow steel 100 comprises a fastening means 110 for mounting the plow steel 100 to a main plow steel 200 of the snow plow. Once mounted, the add-on plow steel 100 is in a mounted state, shown in Figures 1-6. In this mounted state, the add-on plow steel 100 is hence mounted to the main plow steel 200, in what is herein denoted an "upright orientation". The add-on plow steel is associated with a width dimension W, a height dimension H and a depth dimension D. As used herein, the term "dimension" refers to a double-directed direction. The dimensions W, H and D can be mutually perpendicular, and together they can therefore define a coordinate system. In said upright position, the height dimension H is 5 preferably vertical or at least substantially vertical, such as less than 10° from vertical. Similarly, the width dimension W and the depth dimension D are both, in the upright position, preferably horizontal or at least substantially horizontal, such as less than 10° from horizontal. w The main plow steel 200 can be a plow steel 200 that is mounted onto the snow plow in a per se conventional manner, for use during snow plowing operation also in a per se conventional manner. The add-on plow steel 100 can then selectively be mounted onto the main plow steel 200 to reinforce the main plow steel 200 during such operation. is The add-on plow steel 100 comprises a main steel support plate 120. The main steel support plate 120 has a main plane of extension, extending across the width dimension W and the height dimension H. The main plane can extend perpendicular to the depth dimension D.

[0030] The main steel support plate 120 can be generally flat, and can have a generally elongated0 shape extending in the width dimension W. In some embodiments, the main steel support plate 120 can be at least five times longer, in the width dimension W, than tall, in the height dimension H, when the add-on plow steel 100 is in the upright position.

[0031] In exemplifying embodiments, the main steel support plate 120 can be at least 20 mm, such5 as at least 30 mm, such as at least 40 mm, tall in the height dimension H. Correspondingly, the main steel support plate 120 can be at the most 100 mm, such as at the most 80 mm, such as at the most 60 mm, tall in the height dimension H, in the upright position. In the particular exemplary embodiment illustrated in the Figures, the main steel support plate 120 is 48 mm tall in the height dimension H. The size of the main steel support plate 120 in0 the height dimension H can be smaller than that of a main steel support plate 220 of the main plow steel 200, such as at the most half the corresponding size. Moreover, the main steel support plate 120 can be at least 400 mm, such as at least 500 mm, such as at least 600 mm, wide in the width dimension W. Correspondingly, the main steel support plate 120 can be at the most 2000 mm, such as at the most 1500 mm, such as at the most 1000 mm, wide in the width dimension W. In the particular exemplary embodiment illustrated in the Figures, the main steel support plate 120 is 608 mm wide in the width dimension W. The size of the main steel support plate 120 in the width dimension W can be smaller than that of a main steel support plate 220 of the main plow steel 200, such as at the most half the corresponding size.

[0032] The main plow steel 200 comprises a surface contacting edge 230, running along the width dimension W along the main steel support plate 220 of the main plow steel 200 and being arranged to contact the ground 10 when the main plow steel 200 is mounted on the snow plow and the snow plow is used for plowing operation. As illustrated in the Figures, the surface contacting edge 230 can be a lower-most edge of the main steel support plate 200.

[0033] The surface contacting edge 230 can furthermore comprise a surface contacting insert 240, that can be made of wear-resistant material with better abrasive resistance to wear as compared to the steel material of the main steel support plate 220. The wear-resistant material of the insert 240 can be tungsten carbide. It may also be other materials that are considerably harder than the steel type used in the main steel support plate 220, such as chrome carbide. The abrasive resistance of the material of the inserts 240 can be at least three, preferably at least five times larger, as measured in HBW, than that of the material of the main metal steel support plate 120.

[0034] It is realized that the main plow steel 200 can also, in some embodiments, be arranged without such wear-resistant insert 240. Moreover, in some embodiments, the main plow steel 200 can comprise several such inserts 240, such as two or more such inserts 240 arranged one after the other along the width dimension W with intervals therebetween with- out any more abrasive-resistant material. In a way corresponding to what has been said above in relation to the main steel support plate 220 of the main plow steel 200, as well as to its insert(s) 240, the main steel support plate 120 of the add-on plow steel 110 can also comprise a surface contacting edge 130, running along the width dimension W along the main steel support plate 120 and being s arranged to contact the ground 10 when the add-on plow steel 100 is in the mounted state on the main plow steel 200 and the snow plow is configured for plowing operation.

[0035] Further correspondingly, the surface contacting edge 130 can comprise a surface contacting insert 140 made of a wear-resistant material with better abrasive resistance than the steel w material of the main steel support plate 120. The abrasive-resistant material can be of the same general type as described regarding the material of the insert 240, and the materials of inserts 140, 240 can be the same or different. In a way further corresponding to what has been said above regarding the inserts 240, the insert 140 can be one, two or more than two separate inserts, such as arranged one after the other along the width dimension W with or is without separation.

[0036] Hence, when the main plow steel 200 is mounted on the snow plow for plowing operation and the add-on plow steel 100 is mounted on the main plow steel 200 (in its mounted state), both surface contacting edges 130, 230 are arranged to contact the ground 10. During plow-0 ing operation, the snow plow is arranged to move in a direction along the ground 10 that has at least a non-zero component in the depth dimension D, so that the surface contacting edges 130, 230 are scraped along the ground one after the other. Normally, the add-on plow steel 100 will be mounted in front of the main plow steel 200, so that the surface contacting edge 130 of the add-on plow steel 100 hits a non-plowed part of the ground 105 before the surface contacting edge 230 of the main plow steel 100.

[0037] This way, the add-on plow steel 100 serves to offload some of the abrasive wear from the main plow steel 200, effectively prolonging the useful life of the main plow steel 200. 0 As shown in the Figures, the add-on plow steel 100 comprises at least two protrusions 150, 160 that each extend upwards in the height dimension H from the main steel support plate 120, when the add-on plow steel 100 is in the upright orientation, away from the surface contacting edge 130.

[0038] The fastening means 110 can be arranged on both the at least two protrusions 150, 160, but possibly outside of, such as above, the main steel support plate 120 of the add-on plow steel 100 as viewed in a projection along the depth dimension D. In the example shown in the Figures, there are two fastening means 110 per protrusion 150, 160, even if it is realized that this number can also be one fastening means 110 per protrusion 150, 160 for one or several protrusions 150, 160.

[0039] Each of the at least two protrusions 150, 160 can be formed as separate parts, for instance fastened to the main steel support plate 120 using a suitable fastening means such as screws or welding. However, it is preferred that each of the at least two protrusions 150, 160 are formed integrally with the main steel support plate 120, so that the main steel support plate 120 and each of the protrusions 150, 160 form one connected homogeneous steel material body. This is preferred both from a cost perspective, from a strength perspective and from a thermal stress perspective.

[0040] In other words, the main steel support plate 120 may not necessarily be a distinct, elongated part of its own, but may be a subpart of the integrated body forming the add-on plow steel 100. It is, however, noted that the main steel support plate 120 can form such a subpart with a distinct elongated shape when ignoring the at least two protrusions 150, 160. This elongated shape can be rectangular or substantially rectangular in the main plane of extension, and / or can have a constant or substantially constant thickness in the depth dimension D.

[0041] However, a cross-section of the add-on plow steel 100, the cross-section taken in the main plane of extension of the main steel support plate 120, occupies at the most 80%, such as at the most 75%, such as at the most 70%, such as at the most 65%, of an area of a certain defined minimal rectangle. Such cross-section is illustrated in Figure 11, where a section defined by the cross-section has been removed. The defined minimal rectangle is illustrated in Figures 4 and 9 as a hatched rectangle, and is defined in the main plane of the main steel support plate 120 as the smallest possible rectangle so that both the main steel support plate 120 itself and in addition thereto the at least two protrusions 150, 160 are inscribed in the minimal rectangle. Hence, the minimal rectangle is defined based on the width W and s height H dimension size of the add-on plow steel 100, and is in other words specific for each individual considered embodiment add-on plow steel 100.

[0042] In the particular exemplary embodiment illustrated in the Figures, the cross-section occupies about 63% of the minimal rectangle, due to the opening(s) or void(s) 101 that will be w discussed below.

[0043] In some embodiments, the cross-section can occupy at least 20%, such as at least 30%, such as at least 50%, such as at least 60%, of the minimal rectangle. is As is evident from the Figures, the non-occupied parts of the minimal rectangle can arise due to one or both of the protrusions 150, 160 extending above the main steel support plate 120 in the height dimension H in the upright orientation; and there being a width-dimensional W distance between adjacent pairs of protrusions 150, 160. 0 The protrusions 150, 160 can extend above the main steel support plate 120 at least more than a height-dimension H size of the main steel support plate 120, such as at least 50% more. In the example shown in the Figures, the protrusions 150, 160 extend above the main steel support plate 120 87.5%, or 90 mm, more than the height-dimension H size of the main steel support plate 120. The total height of each of the at least two protrusions 150,5 160 can be at least 50%, such as at least 60%, of a total height-dimension H size of the addon plow steel 100. In various embodiments, the protrusions 150, 160 can extend at least 50 mm above the main steel support plate 120 in the height dimension H in the upright orientation. 0 The width-dimensional W distance between each adjacent pair of protrusions 150, 160 can be at least larger than a width-dimensional W size of each of the protrusions 150, 160, such as at least 50% wider, such as at least 70% wider. In the example shown in the Figures, the width-dimensional W distance is 92% larger than the width-dimensional W size of the protrusions 150, 160. The width-dimension W size of each protrusion 150, 160 can be at least 50 mm, such as at least 100 mm; and / or at the most 300 mm, such as at the most 200 mm. s In the example shown in the Figures, the width-dimension W size of each protrusion 150, 160 is 130 mm. In various embodiments, the width-dimensional W distance between each adjacent pair of protrusions 150, 160 can be at least 100 mm, such as at least 200 mm; and / or at the most 500 mm, such as at the most 400 mm, such as at the most 300 mm. In the shown example, the width-dimensional W distance between the two protrusions 150, w 160 is 250 mm.

[0044] As illustrated in the Figures, this gives rise to the hole or void 101, in said cross-section, of the add-on plow steel 100, or in case of three or more protrusions 150, 160, several such holes or voids 101. These voids are seen in a projection of the add-on plow steel 100 along is the depth dimension D. In particular, such hole(s) or void(s) 101 is or are at least partly, such as completely, covered by the main plow steel 200 in said projection when the add-on plow steel 100 is in the mounted state.

[0045] Each of the protrusions 150, 160 can have a height-dimension H end point, in the mounted0 state, which is at the same or substantially the same height as a height-dimension H end point of the main steel support plate 120, such as the same height-dimension H end point within 10% or less. Alternatively, each of the protrusions 150, 160 can have a height-dimension H end point which is at least as large as, or larger than, a height-dimension H end point of the main steel support plate 120. 5

[0046] Generally, each of the protrusions 150, 160 can have a width-dimension H end point which is at least as high as, such as higher, than a height-dimension H end point of the protrusion 150, 160 in question. 0 The present inventor has realized that the design of the add-on plow steel 100 in this manner, having less material than what would have been the case if the add-on plow steel 100 would have had a substantially homogenous, rectangular overall shape, provides sufficiently better cooling of built-up heat during plowing operation so that the useful life of the add-on plow steel 100 as a result is significantly improved, in particular with respect to the abrasive-resistant insert 140.

[0047] The example shown in the Figures features exactly two protrusions 150, 160. It is, however, realized that three, four or even more protrusions are foreseeable. However, it is preferred that each such protrusion 150, 160 comprises a respective fastening means 110, so that the add-on plow steel 100 is fastened to the main plow steel 200 only at locations above (in the height dimension H and in the upright orientation) the main steel support plate 120 of the add-on plow steel 100.

[0048] The fastening means 110 can each comprise a respective through hole through the protrusion 150, 160 in question, such through holes being aligned with corresponding fastening means 210 of the main plow steel 200 when the add-on plow steel 100 is in the mounted state. Such corresponding fastening means 210 can also be through holes, for instance so that screws 111 can be inserted through both fastening means 110, 210 to fasten the addon plow steel 100 onto the main plow steel 200 so that it thereby assumes the mounted state.

[0049] The add-on plow steel 100 can comprise one or more connections 151, 152, 161, 162 between each of the protrusions 150, 160 and the main steel support plate 120, such as one such connection on each width-dimension W side of the protrusion 150, 160 in question. In the case wherein the main steel support plate 120 and the protrusion 150, 160 in question form two integral parts of one and the same material body, the connection 151, 152, 161, 162 is just the place where the main steel support plate 120 meets and transitions into the protrusion 150, 160, such as in the main plane of extension; in other cases the connection 151, 152, 161, 162 can comprise some kind of fastening element between the two. At any rate, each protrusion 150, 160 can comprise one or two such connections 151, 152, 161, 162; in the latter case one such connection on either width- dimension H side of the protrusion 150, 160. In the case of two connections 151, 152, 161, 162 per protrusion 150, 160, each protrusion 150, 160 can individually have at least one, but preferably both, such connection 151, 152, 161, 162 between the protrusion 150, 160 in question and the main steel support plate 120 s that is smoothly curved, such as not involving any abrupt direction changes. The smooth curving can then have a radius of curvature R of at least 10%, such as at least 15%, or even at least 20%, of the height-dimension H size of the protrusion 150, 160 in question. In some cases, the radius of curvature R can be at least 10 mm. In the particular example shown in the Figures, the radius of curvature R for each of the connections 151, 152, 161, 162 is 20 w mm. This strikes a good balance between sturdiness of the add-on plow steel 100 and its thermal cooling properties.

[0050] As is illustrated in the Figures, the main steel support plate 120 can extend, in the width dimension W, on one or both ends of the main steel support plate 120, beyond the protru- 15 sions 150, 160, forming a respective free end of the main steel support plate 120. This provides even better cooling properties of the add-on plow steel 100, as it creates one or two additional openings or voids 101 outside of the protrusions 150, 160 (see, for instance, Figure 8). 0 As is perhaps best seen in Figures 5, 6 and 10, the add-on plow steel 100 can have a nonflat shape, as viewed in a cross-section perpendicular to the width dimension W. That the shape is non-flat means that it has at least a surface arranged to face the main plow steel 200 when the add-on plow steel 100 is in its mounted state, this surface being non-flat, i.e. having at least one bend in the depth dimension D. It may also be the case that the entire5 add-on plow steel 100 can be sheet-like but wherein this sheet shape is generally non-flat, i.e. including at least one bend in the depth dimension D.

[0051] In either case, the non-flat shape arranged to face the main plow steel 200 in the mounted state can be complementary to a corresponding shape of the main plow steel 200 when the0 add-on plow steel 100 is in the mounted state. This provides adequate sturdiness while achieving the advantageous thermal cooling properties of the present invention. Preferably, when the add-on plow steel 100 is in its mounted state, across at least 70%, or even 90%, of the main plane of extension occupied by the add-on plow steel 10, any gap between the add-on plow steel 100 and the main plow steel 200 is less than 10 mm, or even less than 5 mm, due to the geometric properties of the non-flat shape. Preferably, the main plow steel s 200 is in direct physical contact with the add-on plow steel 100 in its mounted state.

[0052] In, for instance, Figure 5, the insert 140 is shown as slightly higher than the insert 240 in the height dimension H. It is, however, realized that the inserts 140, 150 can be arranged at the same height in the height dimension H when the add-on plow steel 100 is in its mounted w state.

[0053] As is also shown in Figure 5, the insert 140 can be flanked by a first part 131 of the surface contacting edge 130, arranged to be located closer to the main plow steel 200 in the depth dimension D when the add-on plow steel 100 is in its mounted state, and a second part 132 is of the surface contacting edge 130, arranged to be located further away from the main plow steel 200 in the depth dimension D when the add-on plow steel 100 is in its mounted state.

[0054] Then, the first part 131 can be arranged with a slanting shape, as seen in a cross-section perpendicular to the width dimension W, the shape slanting upwards, in the height dimen-0 sion H from the insert 140 towards the main plow steel 200. The slanting angle can then be at least 10°, such as at least 20°; and / or at the most 40°, such as at the most 30°. In the examples shown in the Figures, the slanting angle is 25°. The second part 132 can be horizontal or slightly curved horizontal when the add-on plow steel 100 is in its mounted orientation. The insert 140 can be arranged in an elongated socket between the first 131 and5 second 132 parts, the socket opening downwards in the height dimension H when the addon plow steel 100 is in its mounted state.

[0055] The add-on plow steel 100 can be generally sheet-shaped and extend generally in the main plane of extension mentioned above, albeit with the above-described non-flat feature(s) to0 form a shape that is complementary to a shape of the main plow steel 200. The generally sheet-shaped add-on plow steel 100 can be between 10 mm and 50 mm thick in the depth dimension D; at least 15 mm thick; and / or at the most 40 mm thick, such as at the most 30 mm thick. In the example illustrated in the Figures, the add-on plow steel 100, in its mounted state, is 19 mm thick at the main steel support plate 120; 20 mm thick in the vicinity of the fastening means 110; and 25 mm thick at its top part, above the fastening means 110 in the height dimension H.

[0056] Above, preferred embodiments have been described. However, it is apparent to the skilled person that many modifications can be made to the disclosed embodiments without departing from the basic idea of the invention.

[0057] Namely, the various measurements discussed above can vary as long as the principle set out in the claims are met. The Figures illustrate one of many possible embodiment example of these principles. Moreover, the plow steel 100 can have additional features in addition to the ones described and exemplified herein.

[0058] Hence, the invention is not limited to the described embodiments, but can be varied within the scope of the enclosed claims.

Claims

C L A I M S1. Add-on plow steel (100) for a snow plow, comprising: a fastening means (110) for mounting the plow steel (100) to a main plow steel (200) s of the snow plow into a mounted state in which the add-on plow steel (100) is in an upright orientation; and a main steel support plate (120), with a main plane extending across a width dimension (W) and a height dimension (H), the width dimension (W) being horizontal and the height dimension (H) being vertical when the add-on plow steel (100) is in the upright ori- w entation, the main steel support plate (120) having a generally elongated shape extending in the width dimension (W), the main steel support plate (120) comprising a surface contacting edge (130), running along the width dimension (W) along the main steel support plate (120) and arranged to is contact the ground when the add-on plow steel (100) is in the mounted state and the snow plow is configured for plowing operation, the surface contacting edge (130) comprising a surface contacting insert (140) made of a wear-resistant material with better abrasive resistance than the main steel material of said steel support plate (120), the add-on plow steel (100) further comprising two protrusions (150, 160) extending0 in the height dimension (H) from the main steel support plate (120) away from the surface contacting edge (130), the fastening means (110) being arranged on both the protrusions (150, 160) outside of the main steel support plate (120), and = a cross-section in the main plane of the add-on plow steel (100) being configured to occupy at the most 75% of an area of a minimal rectangle, the minimal rectangle being defined in the main plane as the smallest possible rectangle so that both the main steel support plate (120) and the protrusions (150, 160) are inscribed in the minimal rectangle c h a r a c t e r i s e d i n that the add-on plow steel (100) is arranged to be mounted in front of the main plow steel (200), so that, during operation of the main0 plow steel with the mounted add-on plow steel (100), the surface contacting edge (130) ofthe main steel support plate (120) hits a non-plowed part of the ground (10) before a surface contacting edge (230) of the main plow steel (100).

2. Plow steel (100) according to claim 1, wherein s the add-on plow steel (100) comprises exactly two of the protrusions (150, 160).

3. Plow steel (100) according to claim 1 or 2, wherein the fastening means (110) comprises a respective through hole through each of the protrusions (150, 160), the through holes being aligned with corresponding fastening means w (210) of the main plow steel (200) when the add-on plow steel (100) is in the mounted state, the corresponding fastening means (210) possibly also being through holes.

4. Plow steel (100) according to any preceding claim, wherein each of the protrusions (150, 160) has a height-dimension (H) end point in the is mounted state of the add-on plow steel (100), which end point is at the same height or higher as compared to a height-dimension (H) end point of the main steel support plate (120).

5. Plow steel (100) according to any preceding claim, wherein 0 each of the protrusions (150, 160) has a width, in the width dimension (W), that is at least as large as a height, in the height dimension (H), of the protrusion (150, 160).

6. Plow steel (100) according to any preceding claim, wherein a connection (151, 152, 161, 162) between each of the protrusions (150, 160) and the main steel support plate (120) is smoothly curved, with a radius of curvature (R) of at least 10% of the height, in the height dimension (H), of the protrusion (150, 160).

7. Plow steel (100) according to any preceding claim, wherein the main steel support plate (120) extends, in the width dimension (W), on both or0 either ends of the main steel support plate (120), beyond the protrusions (150, 160).

8. Plow steel (100) according to any preceding claim, wherein the add-on plow steel (100) has a non-flat shape, as viewed in a cross-section perpendicular to the width dimension (W), that is complementary to a corresponding shape of the main plow steel (200) when the add-on plow steel (100) is in the mounted state.

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