The technical field relates generally to scraper blade devices and methods for cleaning surfaces by removing undesirable materials from the surfaces.
One example of a surface to be cleaned is a roadway surface on which accumulated some snow and/or ice (which are hereafter generically referred to in a non-limitative manner as “frozen water materials”). This is generally done using a rigid blade having a lowermost edge that is in engagement with the roadway surface. The blade is attached to a vehicle, for instance a truck or the like, travelling over the roadway. In this context, the blade is often called a “snowplow”. A snowplow blade is often relatively large so as to maximize the width of the surface cleaned by a single pass. Such concept, however, assumes that the roadway surface is perfectly smooth, flat and free of obstructions. In practice, road surfaces are not. For instance, the surface height often varies irregularly from one end of the lowermost edge of the blade to the other and the surface height varies all the time as the blade moves thereon. The lowermost edge is therefore not always fully in engagement with the roadway surface over its entire length, with the result that some frozen water materials tend to remain on the roadway surface at various locations, especially where the surface height is the lowest compared to the immediate surrounding areas. The efficiency of the cleaning is thus reduced.
Road maintenance operators must often use de-icing chemicals to melt the remaining frozen water materials so as to complete the cleaning. The amounts of de-icing chemicals are generally inversely proportional to efficiency of the cleaning. Thus, if the cleaning is inefficient, more de-icing chemicals are required. This has a direct impact on the operating costs and increases the footprint on the environment.
Still, obstructions can be present on the roadway surface and be hit by the lowermost edge of the blade. Some of these obstructions can damage the blade and/or remove a portion of the roadway surface, depending on the nature of the obstructions, when using a rigid blade.
Different approaches have been suggested over the years for mitigating the difficulties experienced with fully-rigid snowplow blades. One approach is presented for instance in Swiss Patent No. 416,708 granted 15 Jul. 1966. This patent uses a series of spring-biased movable plates on the lowermost edge of the blade. It also teaches the use of bolts capable of breaking when subjected to excess stress, such as when the plates hit an obstruction. Similar arrangements are disclosed for instance in U.S. Pat. No. 3,400,475 granted 10 Sep. 1968, in Canadian Patent No. 2,423,830 granted 10 Feb. 2004 and in U.S. Pat. No. 7,467,485 granted 23 Dec. 2008. Another approach is to use a series of plates on the lowermost edge of the blade where the plates are resiliently attached to the rest of the blade. Examples are shown in U.S. Pat. No. 520,479 granted 29 May 1894 and in U.S. Pat. No. 5,743,032 granted 28 Apr. 1998.
Although existing arrangements may have been generally considered adequate for their intended purposes, they have not been entirely satisfactory in all respects. Accordingly, there is still room for many improvements in this area of technology.
In one aspect, there is provided a scraper blade device for cleaning a surface when moving in a forward direction relative to the surface, the scraper blade device having a front surface and a lowermost edge, the scraper blade device including: an upper blade portion generally defining an upper area of the front surface of the scraper blade device; and a bottom blade portion generally defining a bottom area of the front surface of the scraper blade device, the bottom blade portion including a plurality of widthwise-disposed blade segments that are adjoined and juxtaposed to one another, each blade segment having an upper portion, a bottom portion, a front side face and a rear side face, the bottom portion of each blade segment including a bottom edge and the bottom edges of the blade segments forming together the lowermost edge of the scraper blade device, the bottom edge of each blade segment being independently slidingly movable in an up and down movement out of alignment with reference to the bottom edges of the other blade segments, the bottom edges being biased towards a downward working position by a plurality of first bias mechanisms, the bottom edges being also pivotally movable between a forward working position and a rearward tripped position, with reference to the surface to be cleaned, about a pivot axis that is substantially parallel to the lowermost edge of the scraper blade device, the bottom edges being biased towards the forward working position by at least one second bias mechanism.
In another aspect, there is provided a method of cleaning a surface using a scraper blade device having a front surface and a lowermost edge, the method including: moving the scraper blade device in a forward direction; passing the scraper blade device over irregularities on the surface to be cleaned and continuously varying in height a position of independent blade segments forming the lowermost edge of the scraper blade device, the blade segments being biased towards a downward working position by a plurality of first bias mechanisms; and upon hitting an obstruction with the scraper blade device, temporarily pivoting at least some of the blade segments from a forward working position toward a rearward tripped position to clear the obstruction, the blade segments being biased towards the forward working position by at least one second bias mechanism.
For the sake of simplicity, the following description refers only to the example of the scraper blade device 10 for removing frozen water materials from the roadway surface 14 but it must be understood that the proposed concept is not limited to such context. Another thing to note is than the exact overall shape and configuration of the scraper blade device 10 can vary from one implementation to another.
The expression “roadway surface” is used herein in a generic manner. It can include for instance roadway surfaces made of different materials, for instance asphalt, concrete, stones, gravel, earth, etc. The roadway surfaces can be roads for vehicles, parkings, airport runways, sidewalks, etc. Depending on the roadway surfaces to be cleaned, the scraper blade device 10 can have a width between 2 m and 8 m. Other dimensions are also possible.
The scraper blade device 10 of
The scraper blade device 10 illustrated in
The cleaning of the frozen water materials from the roadway surface 14 is generally done as the scraper blade device 10 has its lowermost edge 10a in engagement with the roadway surface 14 and moves in a forward direction so as to push the materials as they accumulate in front of the scraper blade device 10. The forward direction is shown in
Depending on the configuration, the scraper blade device 10 can allow the frozen water materials to move laterally as the scraper blade device 10 moves in the forward direction 22. The frozen water materials can be discharged from one or both sides thereof. In other cases, the frozen water materials accumulating on the front surface 24 can be simply pushed over some distance before the vehicle 12 backs up. Some scraper blade devices can also include one or two side panels to facilitate the handling of the frozen water materials.
Some cleaning can be achieved when moving the scraping blade device 10 in a rearward direction but most of the time the cleaning is done as the scraper blade device 10 moves in the forward direction 22. Of course, if the scraper blade device 10 would be located at the rear of the vehicle 12 in an inverted position, the front surface 24 would be facing the rear side of the vehicle 12 and most of the cleaning would thus be done as the vehicle 12 moves backwards. For the sake of simplicity, reference will only be made to the travel direction of the scraper blade device 10, being understood that the forward/rearward directions may sometimes not correspond to that of the vehicle 12.
The upper blade portion 30 can be made of one or more rigid panels forming a continuous surface. A plurality of reinforcing members 34 is provided at the rear to reinforce the upper blade portion 30 (in
The bottom blade portion 32 includes one or more widthwise-disposed support frame members 40. Four support frame members 40 are provided in the illustrated example.
Each support frame member 40 is pivotally connected to the upper blade portion 30 and can pivot around a pivot axis 42. The pivot axis 42 is substantially parallel to the lowermost edge 10a of the scraper blade device 10. This pivot axis 42 is located at the rear of the front surface 24 of the scraper blade device 10. As will be explained later, the support frame members 40 are independently pivotable between a forward working position (visible in
The bottom blade portion 32 includes a plurality of widthwise-disposed blade segments 50 that are adjoined and juxtaposed to one another. In the example shown in
Each blade segment 50 can have a width that is for instance between 3 cm (about 1.2 inch) and 100 cm (about 39.4 inches), and preferably between 5 cm (about 2.0 inches) and 20 cm (about 7.9 inches). A width of 10 cm (about 3.9 inches) can be a very good compromise for a scraper blade device designed for cleaning frozen water materials from roadway surfaces. Blade segments 50 can be made of different materials, for instances steel, stainless steel or a polymer, to name just a few. In some applications, for instance when a liquid is the material or one of the materials to clean, the blade segments 50 can be made of a resilient material such as rubber or the like.
As can be seen in
The impact of the scraper blade device 10 with an obstruction can cause damages if the stress due to the impact exceeds a certain limit. In
The illustrated support frame member 40 is designed to hold five blade segments 50. However, it is possible to design the support frame member 40 with a different number of blade segments 50. Still, although the scraper blade device 10 illustrated in
As can be seen, each blade segment 50 has an upper portion 50a and a bottom portion 50b having a rectangular cross section. The upper portion 50a is narrower in width than the bottom portion 50b. The bottom portion 50b includes a central hole 70 for receiving a retaining bolt 72. The retaining bolt 72 has a threaded end projecting out of the front side face of the corresponding blade segment 50 when the parts are assembled. A nut 74 holds the retaining bolt 72 but is not tighten enough to prevent the blade segment 50 from sliding. The retaining bolt 72 also holds one end of an elongated arm 76 located on the back side of the first front plate 62. The elongated arm 76 extends substantially parallel to the corresponding slot 66.
In the illustrated example, the opposite end of the elongated arm 76 holds a cylindrical bushing 78. The bushing 78 is attached by a bolt 80 and a corresponding nut 82. A notch 84 in the upper corner of the blade segment 50 provides room for the nut 82.
The illustrated blade segments 50 each include two holes 86, one on each side of the central hole 70, to receive a corresponding grease fitting 88. This way, the interface between the blade segments 50 and the front surface of the first front plate 62 can be lubricated using grease injected under pressure.
The second front plate 64 includes a plurality of apertures 89 on the edge adjacent to the first front plate 62. Each of these apertures 89 allows the upper portion 50a of a corresponding one of the blade segments 50 to extend through the second front plate 64. Also, when the blade segment 50 is in the bottom position, the bushing 78 is located adjacent to the interior of the aperture 89.
The illustrated example includes a plurality of first spring mechanisms connected to the blade segments 50. Each first return spring mechanism cooperates with a single one of the blade segments 50 and urges it away from the upper blade portion 30 (i.e. towards the roadway surface 14).
In the illustrated example, the first return spring mechanisms each include a helical compression spring 90. Each spring 90 extends between a flange 92 welded to the elongated arm 76 near the retaining bolt 72 and a support bar 94 (
It should be noted that the first return spring mechanism can be constructed differently. Other kinds of springs or force-generating arrangements can be used as well, for instance a pneumatic actuator.
As best shown in
The holes 102 of the braces 60 also receive axles 110, each extending between two adjacent ones of the holes 102, as best shown in
In the illustrated example, the bottom blade portion 32 includes a plurality of second return spring mechanisms mounted between each support frame member 40 and the upper blade portion 30. These second return spring mechanisms are each connected to a corresponding one of the support frame members 40 at a location at the rear of the axles 106, thus at the rear of the pivot axis 42. It includes one or more helical compression springs 120 extending from a corresponding one of the axles 110 and a fixed location at the rear of the upper blade portion 30, as shown in
In use, the springs 120 urge the support frame members 40 toward their normal working position. The support frame member 40 is prevented from pivoting further towards the front since the enlarged upper end of the arms 124 engage the top of the rim of their corresponding hole 126.
The scraper blade device 200 includes an upper blade portion 202 and a bottom blade portion 204. This upper blade portion 202 has a curved shape that is useful for cleaning public roadway surfaces, for instance municipal roads or highways to name just a few, at a relatively fast speed. The upper blade portion 202 and the bottom blade portion 204 define together the front surface 206 of the scraper blade device 200.
The scraper blade device 200 also includes a plurality of widthwise-disposed and longitudinally-displaceable blade segments 210 that are adjoined and juxtaposed to one another. Each blade segment 210 is in a sliding engagement with a corresponding support frame member 212 (
Each blade segment 210 includes two portions, namely an upper portion 210a and a bottom portion 210b that are connected together using a flexible member 220. The flexible member 220 can be made for instance a polymeric material. An example of polymeric material is a urethane material or the like. Other kinds of materials are possible as well. Still, one can provide a spring arrangement as the flexible member 220.
The illustrated flexible member 220 is removably connected at the rear of each blade segment 210, for instance using bolts, screws or rivets. Other kinds of connectors are possible as well. In the illustrated example, backplates 222, 224 are provided on the rear side of the flexible members 220 to distribute the forces from the connectors.
Each support frame member 212 is rigidly attached to the upper blade portion 202. It is possible to provide one or more support frame members 212. For instance, it is possible to provide only one support frame member 212 extending the full width of the scraper blade device 200, or to provide two or more support frame members 212 disposed in juxtaposition. In the illustrated example, a plurality of support frame members 212 are provided. The support frame members 212 are hidden under the protective casing 201.
The illustrated blade segment 210 includes one central flange 232 rigidly connected at the back thereof. The flange 232 is designed to be inserted in a corresponding one of the spared-apart and parallel slots 240 of the support frame member 212. This arrangement acts as a guide for the blade segment 210. The spring 230 is connected at its upper end to a flange 234 that is welded to the upper edge of the support frame member 212.
Unlike the scraper blade device 200, blade segments 310 of the scraper blade device 300 do not have flexible members. They can slide up and down like the blade segments 210 to compensate for the unevenness of the roadway surface 14 but the pivot movement in case of an impact with an obstruction 14a is made possible using a pivot connection 320 located between the scraper blade device 300 and a frame member 322 attaching the scraper blade device 300 to a vehicle (not shown) or another supporting structure. In this example, the whole scraper blade device 300 pivots in case of an impact. A tension spring 324 is mounted between the back of the scraper blade device 300 and the frame member 322. The spring 324 provides the return force to pivot the scraper blade device 300 back to its normal working position after an impact. Other kinds of springs and/or configurations are also possible.
The scraper blade device 10 can be made using a manufacturing process that includes any one of the following acts or combinations thereof: cutting, bending, punching, welding, bolting, gluing, painting.
Overall, the proposed concept provides a way to increase the efficiency of the cleaning compared to existing arrangements. Tests showed that on a roadway surface, the overall efficiency of the cleaning of frozen water materials can be increased from about 40% (when using a conventional blade) to an average of about 80%. This yields several advantages, including for instance reducing the amount of de-icing chemicals, increasing road safety, etc.
The proposed concept can also provide other advantages, including: an improved mechanical strength, a facilitated maintenance in case of a failure of a part, the possibility of using the device 10 even in case of a partial failure, an increased travel speed while in use, an increased overall fuel efficiency, a reduction of the damages and wear to the roadway surfaces, a reduction of the amounts of de-icing chemicals released in the environment and a maintenance cost reduction for the operators.
The present detailed description and the appended figures are meant to be exemplary only. A skilled person will recognize that variants can be made in light of a review of the present disclosure without departing from the proposed concept.
Number | Date | Country | Kind |
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2698744 | Apr 2010 | CA | national |
The present case is a divisional of U.S. patent application Ser. No. 13/639,311 filed on 4 Oct. 2012, which is a national stage filing under Section 371 of International patent application No. PCT/CA2011/050187, filed on 6 Apr. 2011 and published in English as WO 2011/123956 on 13 Oct. 2011. PCT/CA2011/050187 claims priority to Canadian patent application No. 2,698,744 filed on 6 Apr. 2010. The entire contents of all these prior patent applications are incorporated herein by reference in their entirety.
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Entry |
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Machine translation of FR1050311. |
Machine translation of FR2179703. |
Machine translation of FR2269608. |
Machine translation of FR2349683. |
International Preliminary Report on Patentability (IPRP) in PCT/CA2011/050187 completed on Aug. 15, 2012. |
The Office Actions dated May 30, 2014, Dec. 10, 2014, Mar. 30, 2015 and Jul. 20, 2015 in parent U.S. Appl. No. 13/639,311. |
Machine translation of DE1299675. |
Number | Date | Country | |
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20160040379 A1 | Feb 2016 | US |
Number | Date | Country | |
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Parent | 13639311 | US | |
Child | 14918290 | US |