WO2004031490A1

WO2004031490A1 - Blade holder for a snow-cleaning device

Info

Publication number: WO2004031490A1
Application number: PCT/SE2003/001545
Authority: WO
Inventors: Gösta Källqvist
Original assignee: Kaellqvist Goesta
Priority date: 2002-10-03
Filing date: 2003-10-03
Publication date: 2004-04-15
Also published as: EP1552065A1; NO20052134D0; NO20052134L; RU2005113286A; AU2003267904A1; ES2340265T3; RU2316627C2; EP1552065B1; DE60330479D1; SE0202920D0; SE0202920L; SE523516C2; ATE451502T1

Abstract

The invention relates to a blade holder, in the form of a beam, connecting a blade to the lower edge of a snow-clearing device, such that the blade can be given a cutting angle, acute or right, to the base and be folded backwards while subjecting the beam to an even load, thereby preventing damage when running into an obstacle, and automatically resume its cutting angle after passing the obstacle. The blade holder (7) comprising a beam (1) with a first fixing element (3) which is adapted to be fixed to the lower edge (6) of the snow-clearing device; a second fixing element (4) which is adapted to engage the rear side of the blade (7), and an active element (5). The active element (5) has an upper side (51) and an underside (52) which are essentially parallel. The active element (5) connects the other two elements (3, 4) and has a stiffening element (8) arranged on the underside (52).

Description

BLADE HOLDER FOR A SNOW-CLEARING DEVICE

The invention relates to a blade holder, in the form of a beam, which connects a blade to the lower edge of a snow-clearing device, such that the blade can be given a cutting angle, acute or right, to the base and can be folded backwards, while subjecting the beam to an even load, thereby preventing damage when running into an obstacle, and automatically resume its cutting angle after passing the obstacle.

In the first place, the invention is intended for use on a snow-clearing device comprising a plough wing, snow scraper or snow blade which is supported by a vehicle or device carrier of some type and which in its lower part has at least one blade serv- ing to engage the ground with its cutting edge and ensure a snow-cutting and, when required, a snow-raising action. Use is normally made of a plurality of relatively short blades which are mounted side by side along the lower edge of the snow-clearing device.

It is desirable that the device should be able to remove substantially all loose snow lying on a roadway, i.e. as far as possible also snow lying in cavities in the form of e.g. ruts in the roadway, to provide a traffic safe base. This means that the blades of the snow-clearing device must be able to operate in close engagement with the roadway, which can be achieved if they are flexibly fixed to the lower part of the plough and thus can be individually inclined relative to the lower part of the plough. It is also desirable that the device should be able to cut or scrape away snow or ice stuck to the roadway. Moreover,- it should be possible to carry out the above-mentioned snow- clearing work at high speed. It goes without saying that snow-clearing under these conditions subjects both the snow-clearing device and the device carrier to heavy stress, and they can be damaged if the blade strikes against a stationary obstacle, such as protruding gutters, kerbs, and railway tracks.

To protect the device and the device carrier against damage arising when running into an obstacle, it is previously known to mount the blade to be pivotable backwards, against the action of a spring, about a hinge located above the blade. In this case, the blade must be essentially vertically oriented to the roadway, thereby making it possible for the lower edge of the blade to move backwards/upwards without causing a lifting motion of the device. It is not possible to position the blade at an evidently positive angle relative to the vertical plane, i.e. with the lower edge of the blade extended forwards in the travelling direction. With this design, the blade therefore operates with a scraping effect on the roadway, thereby making it necessary to press the blade against the roadway relatively firmly to ensure good snow-clearing results. The construction also results in the throwing ability being limited.

A prior-art arrangement for protecting devices and device carriers when the blade is oriented at an acute cutting angle to the roadway is disclosed in International Patent Application WO 95/23894. The blade is hingedly attached to the front end of a for- wardly extended pivot arm. When running into an obstacle, the blade can, against the action of a spring, be folded backwards while at the same time the pivot arm is raised against the action of another spring. In this construction, the blade has a positive angle relative to the vertical plane and also vertical flexibility on the roadway. However, a drawback is the fact that the blade cannot be inclined and, thus, does not achieve the flexibility that is required to obtain a good snow-clearing effect on a rutted roadway. Besides, the mechanical construction requires much repair and maintenance since it is subjected to heavy wear and is easily damaged in this environment.

Swedish patent SE 507,556 A describes a device which solves many of the above problems and shows a durable construction which ensures that the blade has a certain degree of flexibility on the base and which can be folded upwards/backwards when running into an obstacle. The device comprises a trilateral hollow beam, which due to its shape can be buckled and then resume its shape after passing the obstacle. A drawback of the triangular hollow beam according to the patent, however, is that there is a risk of uneven stress in the beam when running into an obstacle. This means that an action in the beam in some cases is absorbed by only a small part of the beam, whereby this part is exposed to great strain. A further drawback of the device is that it functions only for ploughs in which a good throwing ability is desired, i.e. the blade must have an acute angle to the roadway. If the device is to be used for dealing of roads or some other clearing where a vertical blade position is preferred, the flexibility on the base is poor.

One of the objects of the invention is to solve the above problems and provide a blade holder which obtains an even arcuate shape when subjected to stress and has the same mobility and flexibility on the base independently of the cutting angle. The invention is shown in an acute embodiment and a vertical embodiment. Independently of the cutting angle, the blade holders can be connected to different types of ploughs by having the same connecting profile. In most cases, snow-clearing is currently carried out on contract by a main contractor who makes agreements with small haulage contractors. This means that a haulage contractor can receive highly varying tasks year by year: one year clearing of salted, busy roadways, and the other year clearing of small roads with a snowy roadway or streets in a municipality. Owing to the various tasks, the haulage contractor must have at least two types of ploughs which cost a lot of money. With a blade holder according to the invention, the plough does not have to be exchanged, but a change of blade holder gives the plough new properties.

The invention is based on the idea of using a flexible material to make a blade holder which acts as pressure springs along the length of the blade and presses the blade in its engaging direction, cutting angle, against the base so that the blade can follow the base in the vertical direction and provide close engagement in ruts and with ridges of the roadway.

The blade holder orients the blade at an optional cutting angle to the blades, which results in a good clearing and throwing ability as well as flexible use of devices. The blade is folded away backwards when it strikes against stationary obstacles such as gutters, kerbs etc. and automatically resumes its working position after passing the obstacle. This is achieved by an active element being adapted, in case of an overload pressure, to be folded (buckled outwards) so that the blade is temporarily folded backwards and then returned to its working position by the elasticity of the element.

The invention solves the above problems by a blade holder, comprising a beam having an active element with a stiffening element and a second fixing element which can give the blade a cutting angle of 0-90 degrees, according to the appended claims.

Embodiments of the invention will now be described in more detail with reference to the accompanying drawings.

Fig. 1 shows a blade holder according to an embodiment of the invention seen from the plough.

Figs ; 2a-b are cross-sectional views of the blade holder along lines AA and BB.

Fig. 3 is a bottom view of the blade holder.

Fig. 4a is a side view in cross-section through a first embodiment of the blade holder.

Fig. 4b shows the same blade holder when moving over an uneven base.

Fig. 4c shows the same blade holder when the blade strikes against an obstacle. Fig. 5a shows the same blade holder in cross-section through a stiffening element.

Fig. 5b shows the same blade holder and stiffening element when moving over an uneven base.

Fig. 5c shows the same blade holder and stiffening element when the blade strikes against an obstacle.

Fig. 6a is a side view in cross-section through a second embodiment of the blade holder.

Fig. 6b shows the same blade holder when moving over an uneven base. F Fiigg.. 6 6cc shows the same blade holder when the blade strikes against an obstacle.

Fig. 7a shows the same blade holder in cross-section through a stiffening element.

Fig. 7b shows the same blade holder and stiffening element when moving over an uneven base. F Fiigg.. 7 7cc shows the same blade holder and stiffening element when the blade strikes against an obstacle.

Figs ; 8a-b illustrate the two embodiments connected to a plough.

Figs 9a-b illustrate alternative embodiments of the blade holder.

Fig. 10 illustrates a plough wing with a plurality of blades arranged side by side.

Fig. 1 illustrates a blade holder according to the invention. The blade holder comprises a beam (1) with fixing elements (3, 4) to a plough (6) and a blade (7). The beam also comprises an active element (5) with an upper side (51) and an underside (52). The active element (5) connects the other two elements (3, 4). The beam further comprises two stiffening elements (8) arranged on the underside (52). Fig. 2a is a cross-sectional view of the beam along line AA. For the beam to have the bending and turning properties that are required, the upper side (51) and the underside (52) are essentially parallel. Fig. 2c is a cross-sectional view of the beam along line BB at one of the stiffening elements (8). The stiffening elements (8) balance the bending resistance of the beam so that the beam will obtain an even arcuate shape when subjected to stress. They are arranged close to the centre of the beam in order to facilitate the warping tendency, which is favourable for the engagement of the blade with the roadway, especially on roads with ruts and ridges. The stiffening elements (8) are preferably made as an integral part of the beam. Fig. 3 shows the beam (1) from below with the bevelled surfaces (81) of the stiffening elements (8) towards the underside (52). The blade holder (1) can be fixed to the lower edge (6) of the snow-clearing device using, for instance, a bolt joint (31). The first fixing element (3) may comprise, for example, a steel ruler which is fixed by casting and has threaded holes or, as shown in Figs 1-2, bolts (31) which are fixed by casting and optionally reinforced by a steel ruler (32) or washer. In the Figures (see Fig. 4) this lower edge (6) is an essentially vertical fixing surface (61), to which the first fixing element (3) is fixed. Above the blade holder there is an essentially horizontal surface (62), which passes into an essentially vertical plough blade (63). See Figs 8a-b which are general views of the blade holder according to the two embodiments as shown, connected to a plough.

The second fixing element (4) serves as attachment for a blade (7). This part of the beam thus engages the rear side of the blade and is, in its lower part, formed with holes (40) for releasable fixing of the blade (7) by a means (41) for fastening. The fastening of the blade can be carried out in a conventional manner using e.g. a key and a key bolt (41) and the blade can be a reversible blade with fixing holes arranged in pairs.

Figs 4-5 illustrate a first embodiment of the invention. The holder comprises a beam (1) having a first fixing element (3), here in the form of a bolt joint (31), which is adapted to be fixed to the lower edge (6) of the snow-clearing device; a second fixing element (4), which is adapted to engage the rear side of the blade (7); and an active element (5) connecting the other two elements (3, 4). A means (41) is arranged on the second fixing element (4) for attaching the blade to the beam (1). The shape of the second fixing element (4) gives the blade (7) a cutting angle (A). This angle can be varied between 0 and 90 degrees; in practice between 20 and 90 degrees. In the embodiment according to Figs 4-5, the blade has a cutting angle of about 90 degrees. The shape of the second fixing element 4 does not affect the function of the holder to any considerable extent. The active part of the construction is the active element (5), which also is shown in Figs 4b, 5b, 6b and 7b. The Figures show how the beam (1) moves vertically to provide adequate engagement with the ground.

Fig. 5 is a cross-sectional view of a stiffening element (8) arranged on a beam according to the first embodiment. The stiffening elements (8) cause an even stress in the whole beam. Without stiffening elements (8) there is a risk that the beam is buckled in one place when subjected to stress. With stiffening elements (8), the beam will obtain a soft arcuate shape when subjected to stress. The stiffening elements (8) also produce the additional force that is required to reset the blade in the operating posi- tion after being released when passing a stationary obstacle. The beam (1) is provided with two stiffening elements (8), but depending on length, material hardness and other factors, the number can be greater. In the embodiments, the stiffening elements are shown as an integral part of the same material as the blade holder, but they can also be made of other materials, such as metal, fixed by casting or in some other manner to the blade holder.

Figs 6-7 show a second embodiment of the invention. The holder comprises a beam (1) having a first fixing element (3) which is adapted to be fixed to the lower edge (6) of the snow-clearing device; a second fixing element (4) which is adapted to engage the rear side of the blade (7); and an active element (5) connecting the other two elements (3, 4). In this embodiment, the blade has an acute cutting angle (A).

Figs 4c, 5c, 6c and 7c show how the active element (5) moves upwards when the blade strikes against an obstacle. The active element (5) will be buckled upwards while at the same time the fixing element (4) is buckled forwards/upwards owing to the upward force caused by the blade as it is being raised vertically. The movement is reinforced by a turning moment being generated in the active element (5). The blade obtains a dragging angle. After having passed the obstacle, the blade holder springs back to its working position. To ensure that there is space enough for the active element to move, there is an empty space (9) between the upper side (51) of the active element and the horizontal surface (62) of the snow-clearing device. A shield (13) is arranged to prevent the space (9) from being filled with snow or ice. In the embodiments, this shield (13) is part of the blade holder and is suitably made of the same material. When the blade holder moves, the shield (13) slides along the plough (63) and prevents snow from filling the space (9). It would also be possible to arrange the shield on the snow-clearing device in a manner sliding along the holder.

A common feature of the two embodiments shown is that the holder connects a blade (7) to the lower edge (6) of a snow-clearing device, such that the blade is given a cutting angle (A) to the base. To prevent damage when running into an obstacle, the blade is folded backwards and automatically resumes its cutting angle after the obstacle. The active part of the holder is the active element (5) which is made of an elastic polymer material. The active element (5) ensures that the second fixing ele- ment (4) is transversely elastic and longitudinally flexible. At least the active element (5), and preferably also the first and second fixing elements, is made of an elastic polymer material which ensures that the beam is transversely elastic and longitudinally flexible. Various types of durable elastomeric materials are conceivable as polymer materials, for instance urethane rubber or some other type of rubber. Polyurethane is a preferred type of material.

However, it is preferred to make the entire beam as an integral piece of the same elastic polymer material, as shown in the Figures. It is particularly preferred to make the beam of e.g. urethane rubber. The urethane rubber should have a Shore A hardness of at least 50° and, in several applications, preferably 70-90°.

Figs 9a-b show another embodiment of the active element (5). The beam is not massive, but has a cavity (50) which is filled with a compressible material having other properties than the urethane plastic of which the active element (5) is made. An example of a suitable material for filling the cavity (50) is foam plastic.

Fig. 10 is a schematic view of a plough blade (14) at the lower edge of which a number of blades (7) are mounted side by side. Each blade can be mounted with a blade holder having a length corresponding to the length of the blade. In the working posi- tion, the blades should have a suitable contact pressure on the roadway for effective clearing to take place. Owing to the elasticity of the beam, the blade is inclined, as shown in an enlargement of a detail in Fig. 10, on an uneven base, for instance due to ruts or ridges. It is the active element (5) of the beam that acts as a spring and holds the blade in position when it is affected by friction against the base and also when the blade is inclined in the lateral direction.

In the invention, the active element is initially tender, which means that it moves even at very small loads. This provides better flexibility on the roadway. Close engagement with the base can be achieved with relatively small forces, which reduces wear on blade and base. The blade holder also makes it possible to easily change the properties of a plough by changing the cutting angle of the blade. The blade holder can be made with the blade attached at an optional angle.

Claims

1. A holder for connecting a blade (7) to the lower edge (6) of a snow-clearing device, such that the blade is given an angle (A) to the base and can be folded backwards, thereby avoiding damage when ruiming into an obstacle, and automatically resume its angle (A) after passing the obstacle, comprising a beam (1) which comprises a first fixing element (3) which is adapted to be fixed to the lower edge (6) of the snow-clearing device; a second fixing element (4) which is adapted to engage the rear side of the blade (7); a means (41) for attaching the blade to the beam (1); c h a r a c t e r i s e d in that the beam further comprises an active element (5) which is adapted to arrange the blade (7) resiliently in the vertical direction and has an upper side (51) and an underside (52) and which connects the other two elements (3, 4) and has a stiffening element (8) arranged on the underside (52).

2. A holder as claimed in claim 1, c h a r a c t e r i s e d in that the upper side (51) and the underside (52) are essentially parallel.

3. A holder as claimed in claim 1 or 2, c h a r a c t e r i s e d in that a lateral cross-section through the beam (1) at the stiffening element (8) is greater than a similar cross-section through the beam at the side of the stiffening element (8).

4. A holder as claimed in claims 1-3, c h a r a c t e r i s e d in that at least the active element (5) consists of an elastic polymer material which ensures that the second fixing element (4) is transversely elastic and longitudinally flexible; and that the second fixing element (4) can give the blade (7) a cutting angle (A) of 0-90 degrees, preferably 20-90 degrees.

5. A holder as claimed in any one of claims 1-4, c h a r a c t e r i s e d in that the beam (1) comprises a shield (13) which in cooperation with a part of the lower edge (6) of the snow-clearing device prevents snow and ice from entering the space (9) above the active element (5).

6. Aholder as claimed in any one of claims 1-5, c h a r a c t e r i s e d in that the first fixing element (3) comprises an essentially vertical side which is adapted to engage an essentially vertical lower edge (61) of the snow-clearing device.

7. Aholder as claimed in any one of claims 1-6, c h a r a c t e r i s e d in that the beam (1) in its entirety consists of an elastic polymer material.

8. A holder as claimed in claim 4 or 7, c h a r a c t e r i s e d in that the elastic polymer material is a polyurethane.

9. A holder as claimed in claim 4 or 7, c h a r a c t e r i s e d in that the elastic polymer material is a urethane rubber with a Shore A hardness of 50°.

10. A holder as claimed in claim 4 or 8, c h a r a c t e r i s e d in that the elastic material polymer material is a urethane rubber with a Shore A hardness of

70-90°.

11. A holder as claimed in any one of claims 1-10, c h a r a c t e r i s e d in that the active element (3) is homogeneous.

12. A holder as claimed in any one of claims 1-10, c h a r a c t e r i s e d in that the active element (3) comprises a cavity (50) filled with a compressible material, for instance foam plastic.