Snow plough with pivotable lateral plough blades

Abstract

A snow plough mountable to a vehicle and comprising a central plough blade (10) fixed to a central support frame (11) and two lateral plough blades (20a, 20b) arranged on opposite sides thereof and fixed to a respective lateral support frame (21a, 21b) that is hinged to the central support frame. The lateral support frame (21a) of a first lateral plough blade is pivotable in relation to the central support frame by a hydraulic cylinder (24a), which is configured to act between the central support frame (11) and the lateral support frame (21a) through a swing arm (30), which is arranged between the central support frame and the hydraulic cylinder, and a connecting link (31), which is arranged between the lateral support frame and the swing arm. The hydraulic cylinder (24a) extends between a pivot joint (J5) on the lateral support frame (21a) and a pivot joint (J4) at an outer end of the swing arm (30).

Description

FIELD OF THE INVENTION AND PRIOR ART

[0001] The present invention relates to a snow plough according to the preamble of claim 1 with a central plough blade and lateral plough blades pivotally connected to the central plough blade on opposite sides thereof. The snow plough is designed for mounting to a vehicle and is to be used for removal of snow from a surface, such as a road surface or ground surface.

[0002] With a snow plough of the above-mentioned type, it is advantageous if each lateral plough blade can be pivoted at an angle of approximately 180° in relation to the central plough blade, to thereby enable each lateral plough blade to be pivoted in relation to the central plough blade between a first end position, in which the lateral plough blade is projecting in a direction rearward from the central plough blade at an angle of approximately 90° in relation to the central plough blade, and a second end position, in which the lateral plough blade is projecting in a direction forward from the central plough blade at an angle of approximately 90° in relation to the central plough blade.

[0003] Vehicle-mounted snow ploughs with a central plough blade and lateral plough blades pivotally connected to the central plough blade on opposite sides thereof are previously known in various configurations. Normally, each lateral plough blade is pivotable in relation to the central plough blade by means of a hydraulic cylinder, which for instance may have a first end articulately connected to the central plough blade and an opposite second end articulately connected to the lateral plough blade, as illustrated in US 5 819 444 A. However, a hydraulic cylinder with a very long stroke length is required with such an arrangement of the hydraulic cylinder. Furthermore, it is not possible to achieve an angular displacement of the lateral plough blade of 180° with such an arrangement of the hydraulic cylinder. In order to make possible a large angular displacement of a lateral plough blade with a hydraulic cylinder having a rather short stroke length, different types of link mechanisms may be used in order to transfer an extension or retraction of the hydraulic cylinder into a pivoting movement of the lateral plough blade in a desired direction in relation to the central plough blade. Such a solution is for instance disclosed in SE 513 718 C2. However, with the type of link mechanism suggested in SE 513 718 C2, an extension or retraction of the hydraulic cylinder in a given increment will cause angular displacements of widely varying increments of the lateral plough blade in dependence on the prevailing angular position of the lateral plough blade in relation to the central plough blade, which implies that the relationship between the linear movement of the hydraulic cylinder and the resulting angular movement of the lateral plough blade will vary widely throughout the stroke length of the hydraulic cylinder in dependence on the prevailing angular position of the lateral plough blade in relation to the central plough blade, which in its turn makes it difficult for the driver of the vehicle to control the movements of the lateral plough blade in relation to the central plough blade in an accurate and precise manner. As a solution to this problem, it has been suggested to pivot a lateral plough blade by means of two hydraulic cylinders arranged in series with each other in the manner described in WO 2006 / 097580 A1.OBJECT OF THE INVENTION

[0004] The object of the present invention is to provide a snow plough of the above-mentioned type that has a new and favourable design.SUMMARY OF THE INVENTION

[0005] According to the present invention, said object is achieved by means of a snow plough having the features defined in claim 1.

[0006] The snow plough according to the invention comprises: an attachment unit, by means of which the snow plough is mountable to a vehicle; a central support frame; a central plough blade fixed to and carried by the central support frame, wherein the central support frame is connected to the attachment unit in order to allow the central support frame to be carried by the vehicle via the attachment unit; first and second lateral plough blades arranged on opposite sides of the central plough blade; a first lateral support frame, wherein the first lateral plough blade is fixed to and carried by the first lateral support frame and wherein the first lateral support frame is hinged to the central support frame at a first end thereof through a first joint and pivotable in relation to the central support frame about a first pivot axis formed by the first joint, to thereby allow the first lateral plough blade to be pivoted in relation to the central support frame together with the first lateral support frame about the first pivot axis between a first end position, in which the first lateral plough blade is projecting in a direction rearward from the central plough blade, and a second end position, in which the first lateral plough blade is projecting in a direction forward from the central plough blade; a second lateral support frame, wherein the second lateral plough blade is fixed to and carried by the second lateral support frame and wherein the second lateral support frame is hinged to the central support frame at a second end thereof through a second joint and pivotable in relation to the central support frame about a second pivot axis formed by the second joint, to thereby allow the second lateral plough blade to be pivoted in relation to the central support frame together with the second lateral support frame about the second pivot axis between a first end position, in which the second lateral plough blade is projecting in a direction rearward from the central plough blade, and a second end position, in which the second lateral plough blade is projecting in a direction forward from the central plough blade; a first hydraulic cylinder for pivoting the first lateral support frame in relation to the central support frame about the first pivot axis, and a second hydraulic cylinder for pivoting the second lateral support frame in relation to the central support frame about the second pivot axis, wherein each one of the first and second hydraulic cylinders comprises a cylinder housing, which has a rear end and an opposite front end, and a piston rod, which is displaceable in relation to the cylinder housing and projects from the front end thereof; and a swing arm, in the following referred to as first swing arm, which at a first end is articulately connected to the central support frame through a third joint, located on the central support frame at a distance from the first joint, so as to be pivotable in relation to the central support frame about a third pivot axis that is formed by the third joint and extends in parallel with the first pivot axis, and which at a second end is articulately connected to the first hydraulic cylinder through a fourth joint, wherein the first hydraulic cylinder is pivotable in relation to the first swing arm about a fourth pivot axis that is formed by the fourth joint and extends in parallel with the first pivot axis.

[0007] The above-mentioned first hydraulic cylinder is articulately connected to the first lateral support frame through a fifth joint, located on the first lateral support frame at a distance from the first joint, so as to be pivotable in relation to the first lateral support frame about a fifth pivot axis A5 that is formed by the fifth joint and extends in parallel with the first pivot axis, wherein the piston rod of the first hydraulic cylinder is fixed to one of said fourth and fifth joints and the cylinder housing of the first hydraulic cylinder is fixed to the other one of said fourth and fifth joints at a position on the cylinder housing located closer to the front end of the cylinder housing than to the rear end thereof.

[0008] According to the invention, the snow plough further comprises a connecting link, in the following referred to as first connecting link, which forms a connection between the first swing arm and the first lateral support frame. At a first end, the first connecting link is articulately connected to the first lateral support frame through a sixth joint located on the first lateral support frame at a position between the first and fifth joints, wherein the first connecting link is pivotable in relation to the first lateral support frame about a sixth pivot axis that is formed by the sixth joint and extends in parallel with the first pivot axis. At a second end, the first connecting link is articulately connected to the first swing arm through a seventh joint located on the first swing arm at a position between the third and fourth joints, wherein the first connecting link is pivotable in relation to the first swing arm about a seventh pivot axis that is formed by the seventh joint and extends in parallel with the first pivot axis.

[0009] An extension of the first hydraulic cylinder is configured to increase the distance between the fourth and fifth joints and, through the combined effect of the first swing arm and the first connecting link, cause the first lateral plough blade to pivot together with the first lateral support frame about the first pivot axis in a direction towards the above-mentioned second end position and at the same time cause the fourth joint to move in an arcuate path about the third pivot axis in a corresponding direction. A retraction of the first hydraulic cylinder is configured to decrease the distance between the fourth and fifth joints and, through the combined effect of the first swing arm and the first connecting link, cause the first lateral plough blade to pivot together with the first lateral support frame about the first pivot axis in a direction towards the above-mentioned first end position and at the same time cause the fourth joint to move in an arcuate path about the third pivot axis in a corresponding direction. Thus, the position of the entire first hydraulic cylinder in relation to the central support frame is constantly changed under the effect of the first swing arm and the first connecting link when the first hydraulic cylinder is extended or retracted in order to pivot the first lateral plough blade in relation to the central plough blade.

[0010] With the solution according to the invention, it is possible to achieve a large angular displacement of a lateral plough blade in relation to a central plough blade, for instance in the order of 180°, with the use of one single hydraulic cylinder having a rather short stroke length, which implies that this solution is cost-efficient and can be implemented in a space-saving and rather simple manner. With the solution according to the invention, it is also possible, in a simple manner, to achieve that an extension or retraction of the hydraulic cylinder in a given increment will cause an essentially uniform angular displacement of the lateral plough blade throughout the stroke length of the hydraulic cylinder, which implies that the relationship between the linear movement of the hydraulic cylinder and the resulting angular movement of the lateral plough blade will vary only slightly throughout the stroke length of the hydraulic cylinder regardless of the prevailing angular position of the lateral plough blade in relation to the central plough blade, which consequently gives a smooth and comparatively uniform movement of the lateral plough blade in relation to the central plough blade and thereby makes it easy for the driver of the vehicle to control the movement of the lateral plough blade in relation to the central plough blade in an accurate and precise manner.

[0011] According to an embodiment of the invention, the first hydraulic cylinder is arranged in such an orientation that the piston rod of the first hydraulic cylinder is fixed to the fifth joint and the cylinder housing of the first hydraulic cylinder is fixed to the fourth joint at a position on the cylinder housing located closer to the front end of the cylinder housing than to the rear end thereof. With this arrangement of the first hydraulic cylinder, the first swing arm may be configured to guide the rear part of the cylinder housing from a position at a rather long distance from the central support frame at the lateral side thereof to an end position behind and very close to the central support frame when the first lateral plough blade is moved from the above-mentioned second end position to the above-mentioned first end position.

[0012] According to another embodiment of the invention, the cylinder housing of the first hydraulic cylinder is fixed to the fourth joint at the front end of the cylinder housing. The required stroke length of the first hydraulic cylinder is hereby minimized.

[0013] According to another embodiment of the invention, the first swing arm is curved with a first concave part provided on a first side of the first swing arm facing the first lateral support frame and a second concave part provided on an opposite second side of the first swing arm facing away from the first lateral support frame, wherein a part of the first joint is configured to be received in said first concave part when the first lateral plough blade is in its second end position and a part of the central support frame is configured to be received in said second concave part when the first lateral plough blade is in its first end position. The first swing arm can hereby be incorporated into the snow plough in a space-saving manner.

[0014] According to another embodiment of the invention, the first connecting link is curved with a concave part provided on a first side of the first connecting link facing the first joint, wherein a part of the first joint is configured to be received in said concave part of the first connecting link when the first lateral plough blade is in its second end position. The first connecting link can hereby be incorporated into the snow plough in a space-saving manner.

[0015] The second hydraulic cylinder is preferably configured to cooperate with a second swing arm and a second connecting link corresponding to and operating in the same manner as the above-mentioned first swing arm and first connecting link, respectively, such that the second lateral plough blade is pivotable in relation to the central plough blade in the same manner as the first lateral plough blade.

[0016] Further advantageous features of the snow plough according to the present invention will appear from the dependent claims and the description following below.BRIEF DESCRIPTION OF THE DRAWINGS

[0017] With reference to the appended drawings, a specific description of embodiments of the invention cited as examples follows below. In the drawings: Figs 1 and 2are perspective views from different directions of a snow plough according to an embodiment of the present invention, Fig 3is a planar view from above of the snow plough of Figs 1 and 2, Fig 4is a perspective view of the snow plough of Figs 1 and 2, as seen with each lateral plough blade pivoted in relation to the central plough blade into a rearwardly projecting first end position, Fig 5is a perspective view of the snow plough of Figs 1 and 2, as seen with each lateral plough blade pivoted in relation to the central plough blade into a forwardly projecting second end position, Fig 6is a perspective view of the snow plough of Figs 1 and 2, as seen with the lateral plough blades aligned with the central plough blade, Figs 7a and 7bare planar views from above of the snow plough of Figs 1 and 2, as seen with the central plough blade set at different angels in relation to an attachment unit of the snow plough, Fig 8is an exploded perspective view of parts included in the snow plough of Figs 1 and 2, Fig 9is a planar view from above of one of the lateral plough blades and a part of the central plough blade included in the snow plough of Figs 1 and 2, as seen with the lateral plough blade aligned with the central plough blade, Figs 10a and 10bare partly cut planar views from above of the lateral plough blade and the part of the central plough blade shown in Fig 9, as seen with the lateral plough blade pivoted in relation to the central plough blade into a first end position, Figs 11a and 11bare partly cut planar views from above of the lateral plough blade and the part of the central plough blade shown in Fig 9, as seen with the lateral plough blade pivoted in relation to the central plough blade into a second end position, and Fig 12is a planar view from above of one of the lateral plough blades and a part of the central plough blade included in a snow plough according to an alternative embodiment of the invention. DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0018] A snow plough 1 according to an embodiment of the present invention is illustrated in Figs 1-11. The snow plough 1 is to be mounted to a motor vehicle, for instance in the form of a front end loader or a tractor, and is intended to be used for removal of snow from a surface, such as a road surface, a parking lot, the ground or any other type of surface. The snow plough 1 comprises an attachment unit 2, by means of which the snow plough is detachably mountable to the vehicle. In the illustrated embodiment, the attachment unit 2 comprises two hooks 3, by means of which the snow plough 1 may be mounted to the lifting arms of a front end loader or tractor.

[0019] The snow plough 1 comprises a central support frame 11 and a central plough blade 10 fixed to and carried by the central support frame 11. The central support frame 11 is connected to the attachment unit 2 in order to allow the central support frame 11 to be carried by the vehicle via the attachment unit 2. The central plough blade 10 is provided with a lower cutting edge 12 that is to be applied against a surface to be subjected to ploughing. In the illustrated embodiment, the cutting edge 12 is fixed to the central plough blade 10 through a spring-loaded cutting edge holder 13 and constitutes a detachable part of the central plough blade 10.

[0020] The snow plough 1 further comprises first and second lateral plough blades 20a, 20b arranged on opposite sides of the central plough blade 10. Each lateral plough blade 20a, 20b is provided with a lower cutting edge 22 that is to be applied against a surface to be subjected to ploughing. In the illustrated embodiment, each cutting edge 22 is fixed to the associated lateral plough blade 20a, 20b through a spring-loaded cutting edge holder 23 and constitutes a detachable part of the associated lateral plough blade 20a, 20b.

[0021] The first lateral plough blade 20a is fixed to and carried by a first lateral support frame 21a, which is hinged to the central support frame 11 through a first joint J1 at a first end of the central support frame, wherein the first lateral support frame 21a is pivotable in relation to the central support frame 11 about an essentially vertical first pivot axis A1 formed by the first joint J1. The first lateral plough blade 20a is, together with the first lateral support frame 21a, pivotable in relation to the central support frame 11 and the central plough blade 10 about the first pivot axis A1 between a first end position (see Figs 4, 10a and 10b), in which the first lateral plough blade 20a is projecting in a direction rearward from the central plough blade 10, and a second end position (see Figs 5, 11a and 11b), in which the first lateral plough blade 20a is projecting in a direction forward from the central plough blade 10. In the illustrated embodiment, the first lateral plough blade 20a is projecting in a direction rearward from the central plough blade 10 at an angle of approximately 90° in relation to the central plough blade in said first end position and in a direction forward from the central plough blade 10 at an angle of approximately 90° in relation to the central plough blade in said second end position. Thus, in this case, the first lateral plough blade 20a is moveable at an angle of approximately 180° between its first and second end positions.

[0022] The second lateral plough blade 20b is fixed to and carried by a second lateral support frame 21b, which is hinged to the central support frame 11 through a second joint J2 at a second end of the central support frame 11 opposite to the above-mentioned fist end of the central support frame 11, wherein the second lateral support frame 21b is pivotable in relation to the central support frame 11 about an essentially vertical second pivot axis A2 formed by the second joint J2. The second lateral plough blade 20b is, together with the second lateral support frame 21b, pivotable in relation to the central support frame 11 and the central plough blade 10 about the second pivot axis A2 between a first end position (see Fig 4), in which the second lateral plough blade 20b is projecting in a direction rearward from the central plough blade 10, and a second end position (see Fig 5), in which the second lateral plough blade 20b is projecting in a direction forward from the central plough blade 10. In the illustrated embodiment, the second lateral plough blade 20b is projecting in a direction rearward from the central plough blade 10 at an angle of approximately 90° in relation to the central plough blade in said first end position and in a direction forward from the central plough blade 10 at an angle of approximately 90° in relation to the central plough blade in said second end position. Thus, in this case, the second lateral plough blade 20b is moveable at an angle of approximately 180° between its first and second end positions.

[0023] The snow plough 1 comprises a double-acting first hydraulic cylinder 24a for pivoting the first lateral support frame 21a in relation to the central support frame 11 about the first pivot axis A1, and a double-acting second hydraulic cylinder 24b for pivoting the second lateral support frame 21b in relation to the central support frame 11 about the second pivot axis A2. Each one of the first and second hydraulic cylinders 24a, 24b comprises a cylinder housing 25, which has a rear end 25a and an opposite front end 25b, and a piston rod 26, which is displaceable in relation to the cylinder housing 25 and projects from the front end 25b thereof. Each hydraulic cylinder 24a, 24b also comprises a piston (not shown) that is slidably received in an internal space of the cylinder housing 25 and configured to divide this space into a chamber on a first side of the piston and another chamber on an opposite second side of the piston, wherein the piston rod 26 is fixed to the piston and extends through one of said chambers.

[0024] The first hydraulic cylinder 24a is configured to act between the central support frame 11 and the first lateral support frame 21a through a link mechanism comprising a swing arm 30 and a link 31, in the following referred to as first swing arm and first connecting link, respectively. The first swing arm 30 has an inner first end facing the central support frame 11 and an outer second end facing the first hydraulic cylinder 24a. At its first end, the first swing arm 30 is articulately connected to the central support frame 11 through a third joint J3 located on the central support frame 11 at the above-mentioned first end thereof and at a distance from the first joint J1, wherein the first swing arm 30 is pivotable in relation to the central support frame 11 about a third pivot axis A3 that is formed by the third joint J3 and that extends in parallel with the first pivot axis A1. At its second end, the first swing arm 30 is articulately connected to the first hydraulic cylinder 24a through a fourth joint J4, wherein the first hydraulic cylinder 24a is pivotable in relation to the first swing arm 30 about a fourth pivot axis A4 that is formed by the fourth joint J4 and that extends in parallel with the first pivot axis A1.

[0025] The first hydraulic cylinder 24a is articulately connected to the first lateral support frame 21a through a fifth joint J5 located on the first lateral support frame 21a at a distance from the first joint J1, wherein the first hydraulic cylinder 24a is pivotable in relation to the first lateral support frame 21a about a fifth pivot axis A5 that is formed by the fifth joint J5 and that extends in parallel with the first pivot axis A1.

[0026] The first hydraulic cylinder 24a has its piston rod 26 fixed to one of said fourth and fifth joints J4, J5 and its cylinder housing 25 fixed to the other one of said fourth and fifth joints J4, J5 at a position on the cylinder housing located closer to the front end 25b of the cylinder housing than to the rear end 25a thereof. Thus, the distance between the fourth and fifth joins J4, J5 is increased by extension of the first hydraulic cylinder 24a and decreased by retraction of the first hydraulic cylinder 24a. In the embodiment illustrated in Figs 1-11, the piston rod 26 of the first hydraulic cylinder 24a is fixed to the fifth joint J5 and the cylinder housing 25 of the first hydraulic cylinder 24a is fixed to the fourth joint J4 at the front end 25b of the cylinder housing. As an alternative, the first hydraulic cylinder 24a may be mounted with its piston rod 26 fixed to the fourth joint J4 and its cylinder housing 25 fixed to the fifth joint J5, as illustrated in Fig 12.

[0027] The first connecting link 31 forms a connection between the first swing arm 30 and the first lateral support frame 21a. The first connecting link 31 has a first end facing the first lateral support frame 21a and an opposite second end facing the first swing arm 30. At its first end, the first connecting link 31 is articulately connected to the first lateral support frame 21a through a sixth joint J6 located on the first lateral support frame 21a at a position between the first joint J1 and the fifth joint J5, wherein the first connecting link 31 is pivotable in relation to the first lateral support frame 21a about a sixth pivot axis A6 that is formed by the sixth joint J6 and that extends in parallel with the first pivot axis A1. At its second end, the first connecting link 31 is articulately connected to the first swing arm 30 through a seventh joint J7 located on the first swing arm 30 at a position between the third joint J3 and the fourth joint J4, wherein the first connecting link 31 is pivotable in relation to the first swing arm 30 about a seventh pivot axis A7 that is formed by the seventh joint J7 and that extends in parallel with the first pivot axis A1.

[0028] In the illustrated embodiment, the distance between the first and third joints J1, J3 is larger than the distance between the first and sixth joints J1, J6, which consequently implies that the distance between the first and third pivot axes A1, A3 is larger than the distance between the first and sixth pivot axes A1, A6. Furthermore, in the illustrated embodiment, the distance between the sixth and first joints J6, J1 is shorter than the distance between the sixth and fifth joints J6, J5, which consequently implies that the distance between the sixth and first pivot axes A6, A1 is shorter than the distance between the sixth and fifth pivot axes A6, A5, and the distance between the seventh and third joints J7, J3 is shorter than the distance between the seventh and fourth joints J7, J4, which consequently implies that the distance between the seventh and third pivot axes A7, A3 is shorter than the distance between the seventh and fourth pivot axes A7, A4.

[0029] An extension of the first hydraulic cylinder 24a is configured to increase the distance between the fourth and fifth joints J4, J5 and, through the combined effect of the first swing arm 30 and the first connecting link 31, cause the first lateral plough blade 20a to pivot together with the first lateral support frame 21a about the first pivot axis A1 in a direction towards the second end position and at the same time cause the fourth joint J4 to move in an arcuate path about the third pivot axis A3 in a corresponding direction. A retraction of the first hydraulic cylinder 24a is configured to decrease the distance between the fourth and fifth joints J4, J5 and, through the combined effect of the first swing arm 30 and the first connecting link 31, cause the first lateral plough blade 20a to pivot together with the first lateral support frame 21a about the first pivot axis A1 in a direction towards the first end position and at the same time cause the fourth joint J4 to move in an arcuate path about the third pivot axis A3 in a corresponding direction.

[0030] In the illustrated embodiment, the first swing arm 30 is curved with a first concave part 32 provided on a first side of the first swing arm facing the first lateral support frame 21a and a second concave part 33 provided on an opposite second side of the first swing arm facing away from the first lateral support frame 21a. A part of the first joint J1 is configured to be received in said first concave part 32 when the first lateral plough blade 20a is in its second end position, as illustrated in Fig 11a, and a part of the central support frame 11 is configured to be received in said second concave part 33 when the first lateral plough blade 20a is in its first end position, as illustrated in Fig 10a. In the illustrated embodiment, the first swing arm 30 comprises two mutually parallel arm parts 35a, 35b located at a vertical distance from each other, as illustrated in Fig 8, wherein the seventh joint J7 comprises a pivot pin 36 that is fixed between the two arm parts 35a, 35b. At their outer ends, the arm parts 35a, 35b are rotatably connected to pivot pins 27 that are fixed to the cylinder housing 25 of the first hydraulic cylinder 24a opposite to each other on opposite sides of the cylinder housing 25. In Figs 10a and 11a, the first swing arm 30 is shown from above, and in Figs 10b and 11b, the first swing arm 30 is shown in a cut across the pivot pin 36, i.e. between the two arm parts 35a, 35b. The first swing arm 30 may also have any other suitable design depending on the specific design of the central support frame 11 and the first lateral support frame 21a.

[0031] In the illustrated embodiment, the first connecting link 31 is curved with a concave part 34 provided on a first side of the first connecting link facing the first joint J1, wherein a part of the first joint J1 is configured to be received in said concave part 34 of the first connecting link 31 when the first lateral plough blade 20a is in its second end position, as illustrated in Fig 11b. The first connecting link 31 may also have any other suitable design depending on the specific design of the central support frame 11 and the first lateral support frame 21a.

[0032] The second hydraulic cylinder 24b is configured to act between the central support frame 11 and the second lateral support frame 21b through a link mechanism comprising a swing arm 40 and a link 41, in the following referred to as second swing arm and second connecting link, respectively. The second swing arm 40 has an inner first end facing the central support frame 11 and an outer second end facing the second hydraulic cylinder 24b. At its first end, the second swing arm 40 is articulately connected to the central support frame 11 through an eighth joint J8 located on the central support frame 11 at the above-mentioned second end thereof and at a distance from the second joint J2, wherein the second swing arm 40 is pivotable in relation to the central support frame 11 about an eighth pivot axis A8 that is formed by the eighth joint J8 and that extends in parallel with the second pivot axis A2. At its second end, the second swing arm 40 is articulately connected to the second hydraulic cylinder 24b through a ninth joint J9, wherein the second hydraulic cylinder 24b is pivotable in relation to the second swing arm 40 about a ninth pivot axis A9 that is formed by the ninth joint J9 and that extends in parallel with the second pivot axis A2.

[0033] The second hydraulic cylinder 24b is articulately connected to the second lateral support frame 21b through a tenth joint J10 located on the second lateral support frame 21b at a distance from the second joint J2, wherein the second hydraulic cylinder 24b is pivotable in relation to the second lateral support frame 21b about a tenth pivot axis A10 that is formed by the tenth joint J10 and that extends in parallel with the second pivot axis A2. The second hydraulic cylinder 24b has its piston rod 26 fixed to one of said ninth and tenth joints J9, J10 and its cylinder housing 25 fixed to the other one of said ninth and tenth joints J9, J10 at a position on the cylinder housing located closer to the front end 25b of the cylinder housing than to the rear end 25a thereof. Thus, the distance between the ninth and tenth joints J9, J10 is increased by extension of the second hydraulic cylinder 24b and decreased by retraction of the second hydraulic cylinder 24b. In the embodiment illustrated in Figs 1-11, the piston rod 26 of the second hydraulic cylinder 24b is fixed to the tenth joint J10 and the cylinder housing 25 of the second hydraulic cylinder 24b is fixed to the ninth joint J9 at the front end 25b of the cylinder housing. As an alternative, the second hydraulic cylinder 24b may be mounted with its piston rod 26 fixed to the ninth joint J9 and its cylinder housing 25 fixed to the tenth joint J10.

[0034] The second connecting link 41 forms a connection between the second swing arm 40 and the second lateral support frame 21b. The second connecting link 41 has a first end facing the second lateral support frame 21b and an opposite second end facing the second swing arm 40. At its first end, the second connecting link 41 is articulately connected to the second lateral support frame 21b through an eleventh joint J11 located on the second lateral support frame 21b at a position between the second joint J2 and the tenth joint J10, wherein the second connecting link 41 is pivotable in relation to the second lateral support frame 21b about an eleventh pivot axis A11 that is formed by the eleventh joint J11 and that extends in parallel with the second pivot axis A2. At its second end, the second connecting link 41 is articulately connected to the second swing arm 40 through a twelfth joint J12 located on the second swing arm 40 at a position between the eighth joint J8 and the ninth joint J9, wherein the second connecting link 41 is pivotable in relation to the second swing arm 40 about a twelfth pivot axis A12 that is formed by the twelfth joint J12 and that extends in parallel with the second pivot axis A2.

[0035] In the illustrated embodiment, the distance between the second and eighth joints J2, J8 is larger than the distance between the second and eleventh joints J2, J11, which consequently implies that the distance between the second and eighth pivot axes A2, A8 is larger than the distance between the second and eleventh pivot axes A2, A11. Furthermore, in the illustrated embodiment, the distance between the eleventh and second joints J11, J2 is shorter than the distance between the eleventh and tenth joints J11, J10, which consequently implies that the distance between the eleventh and second pivot axes A11, A2 is shorter than the distance between the eleventh and tenth pivot axes A11, A10, and the distance between the twelfth and eighth joints J12, J8 is shorter than the distance between the twelfth and ninth joints J12, J9, which consequently implies that the distance between the twelfth and eighth pivot axes A12, A8 is shorter than the distance between the twelfth and ninth pivot axes A12, A9.

[0036] An extension of the second hydraulic cylinder 24b is configured to increase the distance between the ninth and tenth joints J9, J10 and, through the combined effect of the second swing arm 40 and the second connecting link 41, cause the second lateral plough blade 20b to pivot together with the second lateral support frame 21b about the second pivot axis A2 in a direction towards the second end position and at the same time cause the ninth joint J9 to move in an arcuate path about the eighth pivot axis A8 in a corresponding direction. A retraction of the second hydraulic cylinder 24b is configured to decrease the distance between the ninth and tenth joints J9, J10 and, through the combined effect of the second swing arm 40 and the second connecting link 41, cause the second lateral plough blade 20b to pivot together with the second lateral support frame 21b about the second pivot axis A2 in a direction towards the first end position and at the same time cause the ninth joint J9 to move in an arcuate path about the eighth pivot axis A8 in a corresponding direction.

[0037] In the illustrated embodiment, the second swing arm 40 is curved with a first concave part 42 provided on a first side of the first swing arm facing the second lateral support frame 21b and a second concave part 43 provided on an opposite second side of the first swing arm facing away from the second lateral support frame 21b. A part of the second joint J2 is configured to be received in said first concave part 42 when the second lateral plough blade 20b is in its second end position, and a part of the central support frame 11 is configured to be received in said second concave part 43 when the second lateral plough blade 20b is in its first end position. In the illustrated embodiment, the second swing arm 40 comprises two mutually parallel arm parts located at a vertical distance from each other, wherein the twelfth joint J12 comprises a pivot pin that is fixed between the two arm parts. At their outer ends, the arm parts are rotatably connected to pivot pins that are fixed to the cylinder housing 25 of the second hydraulic cylinder 24b opposite to each other on opposite sides of the cylinder housing 25. The second swing arm 40 may also have any other suitable design depending on the specific design of the central support frame 11 and the second lateral support frame 21b.

[0038] In the illustrated embodiment, the second connecting link 41 is curved with a concave part 44 provided on a first side of the first connecting link facing the second joint J2, wherein a part of the second joint J2 is configured to be received in said concave part 44 of the second connecting link 41 when the second lateral plough blade 20b is in its second end position. The second connecting link 41 may also have any other suitable design depending on the specific design of the central support frame 11 and the second lateral support frame 21b.

[0039] In the illustrated embodiment, the central plough blade 10 is pivotable in relation to the attachment unit 2 together with the central support frame 11 about an essentially vertical pivot axis A13 formed by a joint J13 between the attachment unit 2 and the central support frame 11, wherein two single-acting or double-acting hydraulic cylinders 5a, 5b are arranged between the attachment unit 2 and the central support frame 11 on either side of the joint J13 in order to allow the central plough blade 10 to be pivoted in relation to the attachment unit 2 about said pivot axis A13 between a first end position (see Fig 7a) and a second end position (see Fig 7b). By operation of the hydraulic cylinders 5a, 5b, the driver of the vehicle may set the central plough blade 10 in a desired angular position in relation to the attachment unit 2, and by operation of the above-mentioned first and second hydraulic cylinders 24a, 24b, the driver of the vehicle may set each lateral plough blade 20a, 20b in a desired angular position in relation to the central plough blade 10.

[0040] The invention is of course not in any way restricted to the embodiments described above. On the contrary, many possibilities to modifications thereof will be apparent to a person with ordinary skill in the art without departing from the basic idea of the invention such as defined in the appended claims. In the embodiment illustrated in Figs 1-11, the snow plough 1 is designed as a so-called U-plough with a straight central plough blade 10. However, the snow plough 1 according to the present invention may as an alternative be designed as a so-called W-plough with a central plough blade divided at the middle into two parts that may be set at an angle in relation to each other.

Examples

Embodiment Construction

[0018]A snow plough 1 according to an embodiment of the present invention is illustrated in Figs 1-11. The snow plough 1 is to be mounted to a motor vehicle, for instance in the form of a front end loader or a tractor, and is intended to be used for removal of snow from a surface, such as a road surface, a parking lot, the ground or any other type of surface. The snow plough 1 comprises an attachment unit 2, by means of which the snow plough is detachably mountable to the vehicle. In the illustrated embodiment, the attachment unit 2 comprises two hooks 3, by means of which the snow plough 1 may be mounted to the lifting arms of a front end loader or tractor.

[0019]The snow plough 1 comprises a central support frame 11 and a central plough blade 10 fixed to and carried by the central support frame 11. The central support frame 11 is connected to the attachment unit 2 in order to allow the central support frame 11 to be carried by the vehicle via the attachment unit 2. The central plou...

FIELD OF THE INVENTION AND PRIOR ART

[0001] The present invention relates to a snow plough according to the preamble of claim 1 with a central plough blade and lateral plough blades pivotally connected to the central plough blade on opposite sides thereof. The snow plough is designed for mounting to a vehicle and is to be used for removal of snow from a surface, such as a road surface or ground surface.

[0002] With a snow plough of the above-mentioned type, it is advantageous if each lateral plough blade can be pivoted at an angle of approximately 180° in relation to the central plough blade, to thereby enable each lateral plough blade to be pivoted in relation to the central plough blade between a first end position, in which the lateral plough blade is projecting in a direction rearward from the central plough blade at an angle of approximately 90° in relation to the central plough blade, and a second end position, in which the lateral plough blade is projecting in a direction forward from the central plough blade at an angle of approximately 90° in relation to the central plough blade.

[0003] Vehicle-mounted snow ploughs with a central plough blade and lateral plough blades pivotally connected to the central plough blade on opposite sides thereof are previously known in various configurations. Normally, each lateral plough blade is pivotable in relation to the central plough blade by means of a hydraulic cylinder, which for instance may have a first end articulately connected to the central plough blade and an opposite second end articulately connected to the lateral plough blade, as illustrated in US 5 819 444 A. However, a hydraulic cylinder with a very long stroke length is required with such an arrangement of the hydraulic cylinder. Furthermore, it is not possible to achieve an angular displacement of the lateral plough blade of 180° with such an arrangement of the hydraulic cylinder. In order to make possible a large angular displacement of a lateral plough blade with a hydraulic cylinder having a rather short stroke length, different types of link mechanisms may be used in order to transfer an extension or retraction of the hydraulic cylinder into a pivoting movement of the lateral plough blade in a desired direction in relation to the central plough blade. Such a solution is for instance disclosed in SE 513 718 C2. However, with the type of link mechanism suggested in SE 513 718 C2, an extension or retraction of the hydraulic cylinder in a given increment will cause angular displacements of widely varying increments of the lateral plough blade in dependence on the prevailing angular position of the lateral plough blade in relation to the central plough blade, which implies that the relationship between the linear movement of the hydraulic cylinder and the resulting angular movement of the lateral plough blade will vary widely throughout the stroke length of the hydraulic cylinder in dependence on the prevailing angular position of the lateral plough blade in relation to the central plough blade, which in its turn makes it difficult for the driver of the vehicle to control the movements of the lateral plough blade in relation to the central plough blade in an accurate and precise manner. As a solution to this problem, it has been suggested to pivot a lateral plough blade by means of two hydraulic cylinders arranged in series with each other in the manner described in WO 2006 / 097580 A1.OBJECT OF THE INVENTION

[0004] The object of the present invention is to provide a snow plough of the above-mentioned type that has a new and favourable design.SUMMARY OF THE INVENTION

[0005] According to the present invention, said object is achieved by means of a snow plough having the features defined in claim 1.

[0006] The snow plough according to the invention comprises: an attachment unit, by means of which the snow plough is mountable to a vehicle; a central support frame; a central plough blade fixed to and carried by the central support frame, wherein the central support frame is connected to the attachment unit in order to allow the central support frame to be carried by the vehicle via the attachment unit; first and second lateral plough blades arranged on opposite sides of the central plough blade; a first lateral support frame, wherein the first lateral plough blade is fixed to and carried by the first lateral support frame and wherein the first lateral support frame is hinged to the central support frame at a first end thereof through a first joint and pivotable in relation to the central support frame about a first pivot axis formed by the first joint, to thereby allow the first lateral plough blade to be pivoted in relation to the central support frame together with the first lateral support frame about the first pivot axis between a first end position, in which the first lateral plough blade is projecting in a direction rearward from the central plough blade, and a second end position, in which the first lateral plough blade is projecting in a direction forward from the central plough blade; a second lateral support frame, wherein the second lateral plough blade is fixed to and carried by the second lateral support frame and wherein the second lateral support frame is hinged to the central support frame at a second end thereof through a second joint and pivotable in relation to the central support frame about a second pivot axis formed by the second joint, to thereby allow the second lateral plough blade to be pivoted in relation to the central support frame together with the second lateral support frame about the second pivot axis between a first end position, in which the second lateral plough blade is projecting in a direction rearward from the central plough blade, and a second end position, in which the second lateral plough blade is projecting in a direction forward from the central plough blade; a first hydraulic cylinder for pivoting the first lateral support frame in relation to the central support frame about the first pivot axis, and a second hydraulic cylinder for pivoting the second lateral support frame in relation to the central support frame about the second pivot axis, wherein each one of the first and second hydraulic cylinders comprises a cylinder housing, which has a rear end and an opposite front end, and a piston rod, which is displaceable in relation to the cylinder housing and projects from the front end thereof; and a swing arm, in the following referred to as first swing arm, which at a first end is articulately connected to the central support frame through a third joint, located on the central support frame at a distance from the first joint, so as to be pivotable in relation to the central support frame about a third pivot axis that is formed by the third joint and extends in parallel with the first pivot axis, and which at a second end is articulately connected to the first hydraulic cylinder through a fourth joint, wherein the first hydraulic cylinder is pivotable in relation to the first swing arm about a fourth pivot axis that is formed by the fourth joint and extends in parallel with the first pivot axis.

[0007] The above-mentioned first hydraulic cylinder is articulately connected to the first lateral support frame through a fifth joint, located on the first lateral support frame at a distance from the first joint, so as to be pivotable in relation to the first lateral support frame about a fifth pivot axis A5 that is formed by the fifth joint and extends in parallel with the first pivot axis, wherein the piston rod of the first hydraulic cylinder is fixed to one of said fourth and fifth joints and the cylinder housing of the first hydraulic cylinder is fixed to the other one of said fourth and fifth joints at a position on the cylinder housing located closer to the front end of the cylinder housing than to the rear end thereof.

[0008] According to the invention, the snow plough further comprises a connecting link, in the following referred to as first connecting link, which forms a connection between the first swing arm and the first lateral support frame. At a first end, the first connecting link is articulately connected to the first lateral support frame through a sixth joint located on the first lateral support frame at a position between the first and fifth joints, wherein the first connecting link is pivotable in relation to the first lateral support frame about a sixth pivot axis that is formed by the sixth joint and extends in parallel with the first pivot axis. At a second end, the first connecting link is articulately connected to the first swing arm through a seventh joint located on the first swing arm at a position between the third and fourth joints, wherein the first connecting link is pivotable in relation to the first swing arm about a seventh pivot axis that is formed by the seventh joint and extends in parallel with the first pivot axis.

[0009] An extension of the first hydraulic cylinder is configured to increase the distance between the fourth and fifth joints and, through the combined effect of the first swing arm and the first connecting link, cause the first lateral plough blade to pivot together with the first lateral support frame about the first pivot axis in a direction towards the above-mentioned second end position and at the same time cause the fourth joint to move in an arcuate path about the third pivot axis in a corresponding direction. A retraction of the first hydraulic cylinder is configured to decrease the distance between the fourth and fifth joints and, through the combined effect of the first swing arm and the first connecting link, cause the first lateral plough blade to pivot together with the first lateral support frame about the first pivot axis in a direction towards the above-mentioned first end position and at the same time cause the fourth joint to move in an arcuate path about the third pivot axis in a corresponding direction. Thus, the position of the entire first hydraulic cylinder in relation to the central support frame is constantly changed under the effect of the first swing arm and the first connecting link when the first hydraulic cylinder is extended or retracted in order to pivot the first lateral plough blade in relation to the central plough blade.

[0010] With the solution according to the invention, it is possible to achieve a large angular displacement of a lateral plough blade in relation to a central plough blade, for instance in the order of 180°, with the use of one single hydraulic cylinder having a rather short stroke length, which implies that this solution is cost-efficient and can be implemented in a space-saving and rather simple manner. With the solution according to the invention, it is also possible, in a simple manner, to achieve that an extension or retraction of the hydraulic cylinder in a given increment will cause an essentially uniform angular displacement of the lateral plough blade throughout the stroke length of the hydraulic cylinder, which implies that the relationship between the linear movement of the hydraulic cylinder and the resulting angular movement of the lateral plough blade will vary only slightly throughout the stroke length of the hydraulic cylinder regardless of the prevailing angular position of the lateral plough blade in relation to the central plough blade, which consequently gives a smooth and comparatively uniform movement of the lateral plough blade in relation to the central plough blade and thereby makes it easy for the driver of the vehicle to control the movement of the lateral plough blade in relation to the central plough blade in an accurate and precise manner.

[0011] According to an embodiment of the invention, the first hydraulic cylinder is arranged in such an orientation that the piston rod of the first hydraulic cylinder is fixed to the fifth joint and the cylinder housing of the first hydraulic cylinder is fixed to the fourth joint at a position on the cylinder housing located closer to the front end of the cylinder housing than to the rear end thereof. With this arrangement of the first hydraulic cylinder, the first swing arm may be configured to guide the rear part of the cylinder housing from a position at a rather long distance from the central support frame at the lateral side thereof to an end position behind and very close to the central support frame when the first lateral plough blade is moved from the above-mentioned second end position to the above-mentioned first end position.

[0012] According to another embodiment of the invention, the cylinder housing of the first hydraulic cylinder is fixed to the fourth joint at the front end of the cylinder housing. The required stroke length of the first hydraulic cylinder is hereby minimized.

[0013] According to another embodiment of the invention, the first swing arm is curved with a first concave part provided on a first side of the first swing arm facing the first lateral support frame and a second concave part provided on an opposite second side of the first swing arm facing away from the first lateral support frame, wherein a part of the first joint is configured to be received in said first concave part when the first lateral plough blade is in its second end position and a part of the central support frame is configured to be received in said second concave part when the first lateral plough blade is in its first end position. The first swing arm can hereby be incorporated into the snow plough in a space-saving manner.

[0014] According to another embodiment of the invention, the first connecting link is curved with a concave part provided on a first side of the first connecting link facing the first joint, wherein a part of the first joint is configured to be received in said concave part of the first connecting link when the first lateral plough blade is in its second end position. The first connecting link can hereby be incorporated into the snow plough in a space-saving manner.

[0015] The second hydraulic cylinder is preferably configured to cooperate with a second swing arm and a second connecting link corresponding to and operating in the same manner as the above-mentioned first swing arm and first connecting link, respectively, such that the second lateral plough blade is pivotable in relation to the central plough blade in the same manner as the first lateral plough blade.

[0016] Further advantageous features of the snow plough according to the present invention will appear from the dependent claims and the description following below.BRIEF DESCRIPTION OF THE DRAWINGS

[0017] With reference to the appended drawings, a specific description of embodiments of the invention cited as examples follows below. In the drawings: Figs 1 and 2are perspective views from different directions of a snow plough according to an embodiment of the present invention, Fig 3is a planar view from above of the snow plough of Figs 1 and 2, Fig 4is a perspective view of the snow plough of Figs 1 and 2, as seen with each lateral plough blade pivoted in relation to the central plough blade into a rearwardly projecting first end position, Fig 5is a perspective view of the snow plough of Figs 1 and 2, as seen with each lateral plough blade pivoted in relation to the central plough blade into a forwardly projecting second end position, Fig 6is a perspective view of the snow plough of Figs 1 and 2, as seen with the lateral plough blades aligned with the central plough blade, Figs 7a and 7bare planar views from above of the snow plough of Figs 1 and 2, as seen with the central plough blade set at different angels in relation to an attachment unit of the snow plough, Fig 8is an exploded perspective view of parts included in the snow plough of Figs 1 and 2, Fig 9is a planar view from above of one of the lateral plough blades and a part of the central plough blade included in the snow plough of Figs 1 and 2, as seen with the lateral plough blade aligned with the central plough blade, Figs 10a and 10bare partly cut planar views from above of the lateral plough blade and the part of the central plough blade shown in Fig 9, as seen with the lateral plough blade pivoted in relation to the central plough blade into a first end position, Figs 11a and 11bare partly cut planar views from above of the lateral plough blade and the part of the central plough blade shown in Fig 9, as seen with the lateral plough blade pivoted in relation to the central plough blade into a second end position, and Fig 12is a planar view from above of one of the lateral plough blades and a part of the central plough blade included in a snow plough according to an alternative embodiment of the invention. DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0018] A snow plough 1 according to an embodiment of the present invention is illustrated in Figs 1-11. The snow plough 1 is to be mounted to a motor vehicle, for instance in the form of a front end loader or a tractor, and is intended to be used for removal of snow from a surface, such as a road surface, a parking lot, the ground or any other type of surface. The snow plough 1 comprises an attachment unit 2, by means of which the snow plough is detachably mountable to the vehicle. In the illustrated embodiment, the attachment unit 2 comprises two hooks 3, by means of which the snow plough 1 may be mounted to the lifting arms of a front end loader or tractor.

[0019] The snow plough 1 comprises a central support frame 11 and a central plough blade 10 fixed to and carried by the central support frame 11. The central support frame 11 is connected to the attachment unit 2 in order to allow the central support frame 11 to be carried by the vehicle via the attachment unit 2. The central plough blade 10 is provided with a lower cutting edge 12 that is to be applied against a surface to be subjected to ploughing. In the illustrated embodiment, the cutting edge 12 is fixed to the central plough blade 10 through a spring-loaded cutting edge holder 13 and constitutes a detachable part of the central plough blade 10.

[0020] The snow plough 1 further comprises first and second lateral plough blades 20a, 20b arranged on opposite sides of the central plough blade 10. Each lateral plough blade 20a, 20b is provided with a lower cutting edge 22 that is to be applied against a surface to be subjected to ploughing. In the illustrated embodiment, each cutting edge 22 is fixed to the associated lateral plough blade 20a, 20b through a spring-loaded cutting edge holder 23 and constitutes a detachable part of the associated lateral plough blade 20a, 20b.

[0021] The first lateral plough blade 20a is fixed to and carried by a first lateral support frame 21a, which is hinged to the central support frame 11 through a first joint J1 at a first end of the central support frame, wherein the first lateral support frame 21a is pivotable in relation to the central support frame 11 about an essentially vertical first pivot axis A1 formed by the first joint J1. The first lateral plough blade 20a is, together with the first lateral support frame 21a, pivotable in relation to the central support frame 11 and the central plough blade 10 about the first pivot axis A1 between a first end position (see Figs 4, 10a and 10b), in which the first lateral plough blade 20a is projecting in a direction rearward from the central plough blade 10, and a second end position (see Figs 5, 11a and 11b), in which the first lateral plough blade 20a is projecting in a direction forward from the central plough blade 10. In the illustrated embodiment, the first lateral plough blade 20a is projecting in a direction rearward from the central plough blade 10 at an angle of approximately 90° in relation to the central plough blade in said first end position and in a direction forward from the central plough blade 10 at an angle of approximately 90° in relation to the central plough blade in said second end position. Thus, in this case, the first lateral plough blade 20a is moveable at an angle of approximately 180° between its first and second end positions.

[0022] The second lateral plough blade 20b is fixed to and carried by a second lateral support frame 21b, which is hinged to the central support frame 11 through a second joint J2 at a second end of the central support frame 11 opposite to the above-mentioned fist end of the central support frame 11, wherein the second lateral support frame 21b is pivotable in relation to the central support frame 11 about an essentially vertical second pivot axis A2 formed by the second joint J2. The second lateral plough blade 20b is, together with the second lateral support frame 21b, pivotable in relation to the central support frame 11 and the central plough blade 10 about the second pivot axis A2 between a first end position (see Fig 4), in which the second lateral plough blade 20b is projecting in a direction rearward from the central plough blade 10, and a second end position (see Fig 5), in which the second lateral plough blade 20b is projecting in a direction forward from the central plough blade 10. In the illustrated embodiment, the second lateral plough blade 20b is projecting in a direction rearward from the central plough blade 10 at an angle of approximately 90° in relation to the central plough blade in said first end position and in a direction forward from the central plough blade 10 at an angle of approximately 90° in relation to the central plough blade in said second end position. Thus, in this case, the second lateral plough blade 20b is moveable at an angle of approximately 180° between its first and second end positions.

[0023] The snow plough 1 comprises a double-acting first hydraulic cylinder 24a for pivoting the first lateral support frame 21a in relation to the central support frame 11 about the first pivot axis A1, and a double-acting second hydraulic cylinder 24b for pivoting the second lateral support frame 21b in relation to the central support frame 11 about the second pivot axis A2. Each one of the first and second hydraulic cylinders 24a, 24b comprises a cylinder housing 25, which has a rear end 25a and an opposite front end 25b, and a piston rod 26, which is displaceable in relation to the cylinder housing 25 and projects from the front end 25b thereof. Each hydraulic cylinder 24a, 24b also comprises a piston (not shown) that is slidably received in an internal space of the cylinder housing 25 and configured to divide this space into a chamber on a first side of the piston and another chamber on an opposite second side of the piston, wherein the piston rod 26 is fixed to the piston and extends through one of said chambers.

[0024] The first hydraulic cylinder 24a is configured to act between the central support frame 11 and the first lateral support frame 21a through a link mechanism comprising a swing arm 30 and a link 31, in the following referred to as first swing arm and first connecting link, respectively. The first swing arm 30 has an inner first end facing the central support frame 11 and an outer second end facing the first hydraulic cylinder 24a. At its first end, the first swing arm 30 is articulately connected to the central support frame 11 through a third joint J3 located on the central support frame 11 at the above-mentioned first end thereof and at a distance from the first joint J1, wherein the first swing arm 30 is pivotable in relation to the central support frame 11 about a third pivot axis A3 that is formed by the third joint J3 and that extends in parallel with the first pivot axis A1. At its second end, the first swing arm 30 is articulately connected to the first hydraulic cylinder 24a through a fourth joint J4, wherein the first hydraulic cylinder 24a is pivotable in relation to the first swing arm 30 about a fourth pivot axis A4 that is formed by the fourth joint J4 and that extends in parallel with the first pivot axis A1.

[0025] The first hydraulic cylinder 24a is articulately connected to the first lateral support frame 21a through a fifth joint J5 located on the first lateral support frame 21a at a distance from the first joint J1, wherein the first hydraulic cylinder 24a is pivotable in relation to the first lateral support frame 21a about a fifth pivot axis A5 that is formed by the fifth joint J5 and that extends in parallel with the first pivot axis A1.

[0026] The first hydraulic cylinder 24a has its piston rod 26 fixed to one of said fourth and fifth joints J4, J5 and its cylinder housing 25 fixed to the other one of said fourth and fifth joints J4, J5 at a position on the cylinder housing located closer to the front end 25b of the cylinder housing than to the rear end 25a thereof. Thus, the distance between the fourth and fifth joins J4, J5 is increased by extension of the first hydraulic cylinder 24a and decreased by retraction of the first hydraulic cylinder 24a. In the embodiment illustrated in Figs 1-11, the piston rod 26 of the first hydraulic cylinder 24a is fixed to the fifth joint J5 and the cylinder housing 25 of the first hydraulic cylinder 24a is fixed to the fourth joint J4 at the front end 25b of the cylinder housing. As an alternative, the first hydraulic cylinder 24a may be mounted with its piston rod 26 fixed to the fourth joint J4 and its cylinder housing 25 fixed to the fifth joint J5, as illustrated in Fig 12.

[0027] The first connecting link 31 forms a connection between the first swing arm 30 and the first lateral support frame 21a. The first connecting link 31 has a first end facing the first lateral support frame 21a and an opposite second end facing the first swing arm 30. At its first end, the first connecting link 31 is articulately connected to the first lateral support frame 21a through a sixth joint J6 located on the first lateral support frame 21a at a position between the first joint J1 and the fifth joint J5, wherein the first connecting link 31 is pivotable in relation to the first lateral support frame 21a about a sixth pivot axis A6 that is formed by the sixth joint J6 and that extends in parallel with the first pivot axis A1. At its second end, the first connecting link 31 is articulately connected to the first swing arm 30 through a seventh joint J7 located on the first swing arm 30 at a position between the third joint J3 and the fourth joint J4, wherein the first connecting link 31 is pivotable in relation to the first swing arm 30 about a seventh pivot axis A7 that is formed by the seventh joint J7 and that extends in parallel with the first pivot axis A1.

[0028] In the illustrated embodiment, the distance between the first and third joints J1, J3 is larger than the distance between the first and sixth joints J1, J6, which consequently implies that the distance between the first and third pivot axes A1, A3 is larger than the distance between the first and sixth pivot axes A1, A6. Furthermore, in the illustrated embodiment, the distance between the sixth and first joints J6, J1 is shorter than the distance between the sixth and fifth joints J6, J5, which consequently implies that the distance between the sixth and first pivot axes A6, A1 is shorter than the distance between the sixth and fifth pivot axes A6, A5, and the distance between the seventh and third joints J7, J3 is shorter than the distance between the seventh and fourth joints J7, J4, which consequently implies that the distance between the seventh and third pivot axes A7, A3 is shorter than the distance between the seventh and fourth pivot axes A7, A4.

[0029] An extension of the first hydraulic cylinder 24a is configured to increase the distance between the fourth and fifth joints J4, J5 and, through the combined effect of the first swing arm 30 and the first connecting link 31, cause the first lateral plough blade 20a to pivot together with the first lateral support frame 21a about the first pivot axis A1 in a direction towards the second end position and at the same time cause the fourth joint J4 to move in an arcuate path about the third pivot axis A3 in a corresponding direction. A retraction of the first hydraulic cylinder 24a is configured to decrease the distance between the fourth and fifth joints J4, J5 and, through the combined effect of the first swing arm 30 and the first connecting link 31, cause the first lateral plough blade 20a to pivot together with the first lateral support frame 21a about the first pivot axis A1 in a direction towards the first end position and at the same time cause the fourth joint J4 to move in an arcuate path about the third pivot axis A3 in a corresponding direction.

[0030] In the illustrated embodiment, the first swing arm 30 is curved with a first concave part 32 provided on a first side of the first swing arm facing the first lateral support frame 21a and a second concave part 33 provided on an opposite second side of the first swing arm facing away from the first lateral support frame 21a. A part of the first joint J1 is configured to be received in said first concave part 32 when the first lateral plough blade 20a is in its second end position, as illustrated in Fig 11a, and a part of the central support frame 11 is configured to be received in said second concave part 33 when the first lateral plough blade 20a is in its first end position, as illustrated in Fig 10a. In the illustrated embodiment, the first swing arm 30 comprises two mutually parallel arm parts 35a, 35b located at a vertical distance from each other, as illustrated in Fig 8, wherein the seventh joint J7 comprises a pivot pin 36 that is fixed between the two arm parts 35a, 35b. At their outer ends, the arm parts 35a, 35b are rotatably connected to pivot pins 27 that are fixed to the cylinder housing 25 of the first hydraulic cylinder 24a opposite to each other on opposite sides of the cylinder housing 25. In Figs 10a and 11a, the first swing arm 30 is shown from above, and in Figs 10b and 11b, the first swing arm 30 is shown in a cut across the pivot pin 36, i.e. between the two arm parts 35a, 35b. The first swing arm 30 may also have any other suitable design depending on the specific design of the central support frame 11 and the first lateral support frame 21a.

[0031] In the illustrated embodiment, the first connecting link 31 is curved with a concave part 34 provided on a first side of the first connecting link facing the first joint J1, wherein a part of the first joint J1 is configured to be received in said concave part 34 of the first connecting link 31 when the first lateral plough blade 20a is in its second end position, as illustrated in Fig 11b. The first connecting link 31 may also have any other suitable design depending on the specific design of the central support frame 11 and the first lateral support frame 21a.

[0032] The second hydraulic cylinder 24b is configured to act between the central support frame 11 and the second lateral support frame 21b through a link mechanism comprising a swing arm 40 and a link 41, in the following referred to as second swing arm and second connecting link, respectively. The second swing arm 40 has an inner first end facing the central support frame 11 and an outer second end facing the second hydraulic cylinder 24b. At its first end, the second swing arm 40 is articulately connected to the central support frame 11 through an eighth joint J8 located on the central support frame 11 at the above-mentioned second end thereof and at a distance from the second joint J2, wherein the second swing arm 40 is pivotable in relation to the central support frame 11 about an eighth pivot axis A8 that is formed by the eighth joint J8 and that extends in parallel with the second pivot axis A2. At its second end, the second swing arm 40 is articulately connected to the second hydraulic cylinder 24b through a ninth joint J9, wherein the second hydraulic cylinder 24b is pivotable in relation to the second swing arm 40 about a ninth pivot axis A9 that is formed by the ninth joint J9 and that extends in parallel with the second pivot axis A2.

[0033] The second hydraulic cylinder 24b is articulately connected to the second lateral support frame 21b through a tenth joint J10 located on the second lateral support frame 21b at a distance from the second joint J2, wherein the second hydraulic cylinder 24b is pivotable in relation to the second lateral support frame 21b about a tenth pivot axis A10 that is formed by the tenth joint J10 and that extends in parallel with the second pivot axis A2. The second hydraulic cylinder 24b has its piston rod 26 fixed to one of said ninth and tenth joints J9, J10 and its cylinder housing 25 fixed to the other one of said ninth and tenth joints J9, J10 at a position on the cylinder housing located closer to the front end 25b of the cylinder housing than to the rear end 25a thereof. Thus, the distance between the ninth and tenth joints J9, J10 is increased by extension of the second hydraulic cylinder 24b and decreased by retraction of the second hydraulic cylinder 24b. In the embodiment illustrated in Figs 1-11, the piston rod 26 of the second hydraulic cylinder 24b is fixed to the tenth joint J10 and the cylinder housing 25 of the second hydraulic cylinder 24b is fixed to the ninth joint J9 at the front end 25b of the cylinder housing. As an alternative, the second hydraulic cylinder 24b may be mounted with its piston rod 26 fixed to the ninth joint J9 and its cylinder housing 25 fixed to the tenth joint J10.

[0034] The second connecting link 41 forms a connection between the second swing arm 40 and the second lateral support frame 21b. The second connecting link 41 has a first end facing the second lateral support frame 21b and an opposite second end facing the second swing arm 40. At its first end, the second connecting link 41 is articulately connected to the second lateral support frame 21b through an eleventh joint J11 located on the second lateral support frame 21b at a position between the second joint J2 and the tenth joint J10, wherein the second connecting link 41 is pivotable in relation to the second lateral support frame 21b about an eleventh pivot axis A11 that is formed by the eleventh joint J11 and that extends in parallel with the second pivot axis A2. At its second end, the second connecting link 41 is articulately connected to the second swing arm 40 through a twelfth joint J12 located on the second swing arm 40 at a position between the eighth joint J8 and the ninth joint J9, wherein the second connecting link 41 is pivotable in relation to the second swing arm 40 about a twelfth pivot axis A12 that is formed by the twelfth joint J12 and that extends in parallel with the second pivot axis A2.

[0035] In the illustrated embodiment, the distance between the second and eighth joints J2, J8 is larger than the distance between the second and eleventh joints J2, J11, which consequently implies that the distance between the second and eighth pivot axes A2, A8 is larger than the distance between the second and eleventh pivot axes A2, A11. Furthermore, in the illustrated embodiment, the distance between the eleventh and second joints J11, J2 is shorter than the distance between the eleventh and tenth joints J11, J10, which consequently implies that the distance between the eleventh and second pivot axes A11, A2 is shorter than the distance between the eleventh and tenth pivot axes A11, A10, and the distance between the twelfth and eighth joints J12, J8 is shorter than the distance between the twelfth and ninth joints J12, J9, which consequently implies that the distance between the twelfth and eighth pivot axes A12, A8 is shorter than the distance between the twelfth and ninth pivot axes A12, A9.

[0036] An extension of the second hydraulic cylinder 24b is configured to increase the distance between the ninth and tenth joints J9, J10 and, through the combined effect of the second swing arm 40 and the second connecting link 41, cause the second lateral plough blade 20b to pivot together with the second lateral support frame 21b about the second pivot axis A2 in a direction towards the second end position and at the same time cause the ninth joint J9 to move in an arcuate path about the eighth pivot axis A8 in a corresponding direction. A retraction of the second hydraulic cylinder 24b is configured to decrease the distance between the ninth and tenth joints J9, J10 and, through the combined effect of the second swing arm 40 and the second connecting link 41, cause the second lateral plough blade 20b to pivot together with the second lateral support frame 21b about the second pivot axis A2 in a direction towards the first end position and at the same time cause the ninth joint J9 to move in an arcuate path about the eighth pivot axis A8 in a corresponding direction.

[0037] In the illustrated embodiment, the second swing arm 40 is curved with a first concave part 42 provided on a first side of the first swing arm facing the second lateral support frame 21b and a second concave part 43 provided on an opposite second side of the first swing arm facing away from the second lateral support frame 21b. A part of the second joint J2 is configured to be received in said first concave part 42 when the second lateral plough blade 20b is in its second end position, and a part of the central support frame 11 is configured to be received in said second concave part 43 when the second lateral plough blade 20b is in its first end position. In the illustrated embodiment, the second swing arm 40 comprises two mutually parallel arm parts located at a vertical distance from each other, wherein the twelfth joint J12 comprises a pivot pin that is fixed between the two arm parts. At their outer ends, the arm parts are rotatably connected to pivot pins that are fixed to the cylinder housing 25 of the second hydraulic cylinder 24b opposite to each other on opposite sides of the cylinder housing 25. The second swing arm 40 may also have any other suitable design depending on the specific design of the central support frame 11 and the second lateral support frame 21b.

[0038] In the illustrated embodiment, the second connecting link 41 is curved with a concave part 44 provided on a first side of the first connecting link facing the second joint J2, wherein a part of the second joint J2 is configured to be received in said concave part 44 of the second connecting link 41 when the second lateral plough blade 20b is in its second end position. The second connecting link 41 may also have any other suitable design depending on the specific design of the central support frame 11 and the second lateral support frame 21b.

[0039] In the illustrated embodiment, the central plough blade 10 is pivotable in relation to the attachment unit 2 together with the central support frame 11 about an essentially vertical pivot axis A13 formed by a joint J13 between the attachment unit 2 and the central support frame 11, wherein two single-acting or double-acting hydraulic cylinders 5a, 5b are arranged between the attachment unit 2 and the central support frame 11 on either side of the joint J13 in order to allow the central plough blade 10 to be pivoted in relation to the attachment unit 2 about said pivot axis A13 between a first end position (see Fig 7a) and a second end position (see Fig 7b). By operation of the hydraulic cylinders 5a, 5b, the driver of the vehicle may set the central plough blade 10 in a desired angular position in relation to the attachment unit 2, and by operation of the above-mentioned first and second hydraulic cylinders 24a, 24b, the driver of the vehicle may set each lateral plough blade 20a, 20b in a desired angular position in relation to the central plough blade 10.

[0040] The invention is of course not in any way restricted to the embodiments described above. On the contrary, many possibilities to modifications thereof will be apparent to a person with ordinary skill in the art without departing from the basic idea of the invention such as defined in the appended claims. In the embodiment illustrated in Figs 1-11, the snow plough 1 is designed as a so-called U-plough with a straight central plough blade 10. However, the snow plough 1 according to the present invention may as an alternative be designed as a so-called W-plough with a central plough blade divided at the middle into two parts that may be set at an angle in relation to each other.

Examples

Embodiment Construction

[0018]A snow plough 1 according to an embodiment of the present invention is illustrated in Figs 1-11. The snow plough 1 is to be mounted to a motor vehicle, for instance in the form of a front end loader or a tractor, and is intended to be used for removal of snow from a surface, such as a road surface, a parking lot, the ground or any other type of surface. The snow plough 1 comprises an attachment unit 2, by means of which the snow plough is detachably mountable to the vehicle. In the illustrated embodiment, the attachment unit 2 comprises two hooks 3, by means of which the snow plough 1 may be mounted to the lifting arms of a front end loader or tractor.

[0019]The snow plough 1 comprises a central support frame 11 and a central plough blade 10 fixed to and carried by the central support frame 11. The central support frame 11 is connected to the attachment unit 2 in order to allow the central support frame 11 to be carried by the vehicle via the attachment unit 2. The central plou...

Claims

1. A snow plough for a vehicle, the snow plough (1) comprising: - an attachment unit (2), by means of which the snow plough (1) is mountable to a vehicle; - a central support frame (11); - a central plough blade (10) fixed to and carried by the central support frame (11), wherein the central support frame (11) is connected to the attachment unit (2) in order to allow the central support frame (11) to be carried by the vehicle via the attachment unit (2); - first and second lateral plough blades (20a, 20b) arranged on opposite sides of the central plough blade (10); - a first lateral support frame (21a), wherein the first lateral plough blade (20a) is fixed to and carried by the first lateral support frame (21a) and wherein the first lateral support frame (21a) is hinged to the central support frame (11) at a first end thereof through a first joint (J1) and pivotable in relation to the central support frame (11) about a first pivot axis (A1) formed by the first joint (J1), to thereby allow the first lateral plough blade (20a) to be pivoted in relation to the central support frame (11) together with the first lateral support frame (21a) about the first pivot axis (A1) between a first end position, in which the first lateral plough blade (20a) is projecting in a direction rearward from the central plough blade (10), and a second end position, in which the first lateral plough blade (20a) is projecting in a direction forward from the central plough blade (10); - a second lateral support frame (21b), wherein the second lateral plough blade (20b) is fixed to and carried by the second lateral support frame (21b) and wherein the second lateral support frame (21b) is hinged to the central support frame (11) at a second end thereof through a second joint (J2) and pivotable in relation to the central support frame (11) about a second pivot axis (A2) formed by the second joint (J2), to thereby allow the second lateral plough blade (20b) to be pivoted in relation to the central support frame (11) together with the second lateral support frame (21b) about the second pivot axis (A2) between a first end position, in which the second lateral plough blade (20b) is projecting in a direction rearward from the central plough blade (10), and a second end position, in which the second lateral plough blade (20b) is projecting in a direction forward from the central plough blade (10); and - a first hydraulic cylinder (24a) for pivoting the first lateral support frame (21a) in relation to the central support frame (11) about the first pivot axis (A1), and a second hydraulic cylinder (24b) for pivoting the second lateral support frame (21b) in relation to the central support frame (11) about the second pivot axis (A2), wherein each one of the first and second hydraulic cylinders (24a, 24b) comprises a cylinder housing (25), which has a rear end (25a) and an opposite front end (25b), and a piston rod (26), which is displaceable in relation to the cylinder housing (25) and projects from the front end (25b) thereof, characterized in: - that the snow plough (1) comprises a first swing arm (30), which at a first end is articulately connected to the central support frame (11) through a third joint (J3), located on the central support frame (11) at a distance from the first joint (J1), so as to be pivotable in relation to the central support frame (11) about a third pivot axis (A3) that is formed by the third joint (J3) and extends in parallel with the first pivot axis (A1), and which at a second end is articulately connected to the first hydraulic cylinder (24a) through a fourth joint (J4), wherein the first hydraulic cylinder (24a) is pivotable in relation to the first swing arm (30) about a fourth pivot axis (A4) that is formed by the fourth joint (J4) and extends in parallel with the first pivot axis (A1); - that the first hydraulic cylinder (24a) is articulately connected to the first lateral support frame (21a) through a fifth joint (J5), located on the first lateral support frame (21a) at a distance from the first joint (J1), so as to be pivotable in relation to the first lateral support frame (21a) about a fifth pivot axis (A5) that is formed by the fifth joint (J5) and extends in parallel with the first pivot axis (A1), wherein the piston rod (26) of the first hydraulic cylinder (24a) is fixed to one of said fourth and fifth joints (J4, J5) and the cylinder housing (25) of the first hydraulic cylinder (24a) is fixed to the other one of said fourth and fifth joints (J4, J5) at a position on the cylinder housing located closer to the front end (25b) of the cylinder housing than to the rear end (25a) thereof; and - that the snow plough (1) comprises a first connecting link (31), which forms a connection between the first swing arm (30) and the first lateral support frame (21a), wherein the first connecting link (31) at a first end is articulately connected to the first lateral support frame (21a) through a sixth joint (J6), located on the first lateral support frame (21a) at a position between the first and fifth joints (J1, J5), so as to be pivotable in relation to the first lateral support frame (21a) about a sixth pivot axis (A6) that is formed by the sixth joint (J6) and extends in parallel with the first pivot axis (A1), and at a second end is articulately connected to the first swing arm (30) through a seventh joint (J7), located on the first swing arm (30) at a position between the third and fourth joints (J3, J4), so as to be pivotable in relation to the first swing arm (30) about a seventh pivot axis (A7) that is formed by the seventh joint (J7) and extends in parallel with the first pivot axis (A1), wherein an extension of the first hydraulic cylinder (24a) is configured to increase the distance between the fourth and fifth joints (J4, J5) and, through the combined effect of the first swing arm (30) and the first connecting link (31), cause the first lateral plough blade (20a) to pivot together with the first lateral support frame (21a) about the first pivot axis (A1) in a direction towards said second end position and the fourth joint (J4) to move in an arcuate path about the third pivot axis (A3) in a corresponding direction, and wherein a retraction of the first hydraulic cylinder (24a) is configured to decrease the distance between the fourth and fifth joints (J4, J5) and, through the combined effect of the first swing arm (30) and the first connecting link (31), cause the first lateral plough blade (20a) to pivot together with the first lateral support frame (21a) about the first pivot axis (A1) in a direction towards said first end position and the fourth joint (J4) to move in an arcuate path about the third pivot axis (A3) in a corresponding direction.

2. A snow plough according to claim 1, characterized in that the piston rod (26) of the first hydraulic cylinder (24a) is fixed to the fifth joint (J5) and the cylinder housing (25) of the first hydraulic cylinder (24a) is fixed to the fourth joint (J4) at a position on the cylinder housing located closer to the front end (25b) of the cylinder housing than to the rear end (25a) thereof.

3. A snow plough according to claim 2, characterized in that the cylinder housing (25) of the first hydraulic cylinder (24a) is fixed to the fourth joint (J4) at the front end (25b) of the cylinder housing.

4. A snow plough according to any of claims 1-3, characterized in that the distance between the first joint (J1) and the third joint (J3) is larger than the distance between the first joint (J1) and the sixth joint (J6).

5. A snow plough according to any of claims 1-4, characterized in: - that the distance between the sixth joint (J6) and the first joint (J1) is shorter than the distance between the sixth joint (J6) and the fifth joint (J5); and - that the distance between the seventh joint (J7) and the third joint (J3) is shorter than the distance between the seventh joint (J7) and the fourth joint (J4).

6. A snow plough according to any of claims 1-5, characterized in that the first swing arm (30) is curved with a first concave part (32) provided on a first side of the first swing arm (30) facing the first lateral support frame (21a) and a second concave part (33) provided on an opposite second side of the first swing arm (30) facing away from the first lateral support frame (21a), wherein a part of the first joint (J1) is configured to be received in said first concave part (32) when the first lateral plough blade (20a) is in its second end position and a part of the central support frame (11) is configured to be received in said second concave part (33) when the first lateral plough blade (20a) is in its first end position.

7. A snow plough according to any of claims 1-6, characterized in that the first connecting link (31) is curved with a concave part (34) provided on a first side of the first connecting link (31) facing the first joint (J1), wherein a part of the first joint (J1) is configured to be received in said concave part (34) of the first connecting link (31) when the first lateral plough blade (20a) is in its second end position.

8. A snow plough according to any of claims 1-7, characterized in: - that the snow plough (1) comprises a second swing arm (40), which at a first end is articulately connected to the central support frame (11) through an eighth joint (J8), located on the central support frame (11) at a distance from the second joint (J2), so as to be pivotable in relation to the central support frame (11) about an eighth pivot axis (A8) that is formed by the eighth joint (J8) and extends in parallel with the second pivot axis (A2), and which at a second end is articulately connected to the second hydraulic cylinder (24b) through a ninth joint (J9), wherein the second hydraulic cylinder (24b) is pivotable in relation to the second swing arm (40) about a ninth pivot axis (A9) that is formed by the ninth joint (J9) and extends in parallel with the second pivot axis (A2); - that the second hydraulic cylinder (24b) is articulately connected to the second lateral support frame (21b) through a tenth joint (J10), located on the second lateral support frame (21b) at a distance from the second joint (J2), so as to be pivotable in relation to the second lateral support frame (21b) about a tenth pivot axis (A10) that is formed by the tenth joint (J10) and extends in parallel with the second pivot axis (A2), wherein the piston rod (26) of the second hydraulic cylinder (24b) is fixed to one of said ninth and tenth joints (J9, J10) and the cylinder housing (25) of the second hydraulic cylinder (24b) is fixed to the other one of said ninth and tenth joints (J9, J10) at a position on the cylinder housing located closer to the front end (25b) of the cylinder housing than to the rear end (25a) thereof; and - that the snow plough (1) comprises a second connecting link (41), which forms a connection between the second swing arm (40) and the second lateral support frame (21b), wherein the second connecting link (41) at a first end is articulately connected to the second lateral support frame (21b) through an eleventh joint (J11), located on the second lateral support frame (21b) at a position between the second and tenth joints (J2, J10), so as to be pivotable in relation to the second lateral support frame (21b) about an eleventh pivot axis (A11) that is formed by the eleventh joint (J11) and extends in parallel with the second pivot axis (A2), and at a second end is articulately connected to the second swing arm (40) through a twelfth joint (J12), located on the second swing arm (40) at a position between the eighth and ninth joints (J8, J9), so as to be pivotable in relation to the second swing arm (40) about a twelfth pivot axis (A12) that is formed by the twelfth joint (J12) and extends in parallel with the second pivot axis (A2), wherein an extension of the second hydraulic cylinder (24b) is configured to increase the distance between the ninth and tenth joints (J9, J10) and, through the combined effect of the second swing arm (40) and the second connecting link (41), cause the second lateral plough blade (20b) to pivot together with the second lateral support frame (21b) about the second pivot axis (A2) in a direction towards said second end position and the ninth joint (J9) to move in an arcuate path about the eighth pivot axis (A8) in a corresponding direction, and wherein a retraction of the second hydraulic cylinder (24b) is configured to decrease the distance between the ninth and tenth joints (J9, J10) and, through the combined effect of the second swing arm (40) and the second connecting link (41), cause the second lateral plough blade (20b) to pivot together with the second lateral support frame (21b) about the second pivot axis (A2) in a direction towards said first end position and the ninth joint (J9) to move in an arcuate path about the eighth pivot axis (A8) in a corresponding direction.

9. A snow plough according to claim 8, characterized in that the piston rod (26) of the second hydraulic cylinder (24b) is fixed to the tenth joint (J10) and the cylinder housing (25) of the second hydraulic cylinder (24b) is fixed to the ninth joint (J9) at a position on the cylinder housing located closer to the front end (25b) of the cylinder housing than to the rear end (25a) thereof.

10. A snow plough according to claim 9, characterized in that the cylinder housing (25) of the second hydraulic cylinder (24b) is fixed to the ninth joint (J9) at the front end (25b) of the cylinder housing.

11. A snow plough according to any of claims 8-10, characterized in that the distance between the second joint (J2) and the eighth joint (J8) is larger than the distance between the second joint (J2) and the eleventh joint (J11).

12. A snow plough according to any of claims 8-11, characterized in: - that the distance between the eleventh joint (J11) and the second joint (J2) is shorter than the distance between the eleventh joint (J11) and the tenth joint (J10); and - that the distance between the twelfth joint (J12) and the eighth joint (J8) is shorter than the distance between the twelfth joint (J12) and the ninth joint (J9).

13. A snow plough according to any of claims 8-12, characterized in that the second swing arm (40) is curved with a first concave part (42) provided on a first side of the second swing arm (40) facing the second lateral support frame (21b) and a second concave part (43) provided on an opposite second side of the second swing arm (40) facing away from the second lateral support frame (21b), wherein a part of the second joint (J2) is configured to be received in said first concave part (42) of the second swing arm (40) when the second lateral plough blade (20b) is in its second end position and a part of the central support frame (11) is configured to be received in said second concave part (43) of the second swing arm (40) when the second lateral plough blade (20b) is in its first end position.

14. A snow plough according to any of claims 8-13, characterized in that the second connecting link (41) is curved with a concave part (44) provided on a first side of the second connecting link (41) facing the second joint (J2), wherein a part of the second joint (J2) is configured to be received in said concave part (44) of the second connecting link (41) when the second lateral plough blade (20b) is in its second end position.

15. A snow plough according to any of claims 1-14, characterized in that the snow plough is a U-plough.

Images