NO339894B1

NO339894B1 - Device for clearing unpaved roads and forest fire lines

Info

Publication number: NO339894B1
Application number: NO20150581A
Authority: NO
Inventors: Ragnar Lotsberg
Original assignee: T D Bergma
Priority date: 2015-05-11
Filing date: 2015-05-11
Publication date: 2017-02-13
Also published as: NO20150581A1

Description

The present invention is concerning a clearing device, suitable for clearing forest truck roads, farm roads and fire gates, as stated in the preamble of patent claim 1.

Background

Forest truck roads and similar are common in for example Norway, and are unpaved roads that need maintenance to stay passable. However, maintenance of roads like this is demanding and the roads are for that reason not maintained frequently. However, if time between maintenance becomes to long, the roads may grow with fem, scrub and similar, and become impassable. Moreover, deep wheel tracks are formed when the roads are used by heavy transport during periods with heavy rainfall.

A traditional road grader is not applicable to this task. The road grader may be stuck in sharp bends, stumps or rocks in the roadway. A similar problem applies in fire lines in forests. Fire lines will also have to be cleared periodically in order to serve their purpose. Mechanical clearing of fire lines is normally performed by rotary cutters. However, the cutter may hit hidden rocks in the soil that may cut off the knives of the rotary cutter.

WO 03/104567 describes a clearing device for maintaining gravel and forest roads. The device is arranged to be towed and comprises a mat to distribute fines released from the surface from an interconnected grader device. The mat may be assembled from treads from vehicle tires. However, this device is not bending-stiff and is expected to conform to the road surface.

Object

There is a need for a clearing device that overcomes the problems set forth above, that provides a more thorough clearing, including rocks and studs and that also clears bush and similar at the road side. There is also a need for a clearing device that eliminates the problem with rotary cutters used in forest fire lines and that allows clearing at a substantially higher speed.

The invention

The objects above are achieved by a clearing device according to the independent claim. Further advantageous features appear from the dependent claims.

The clearing device is designed to clear and level unpaved roads, such as forest truck roads and farm roads. However, the clearing device is also designed to clear forest fire gates, as described in further details in the detailed description. The clearing device comprises an array of interconnected tire treads, particularly from truck tires. The treads are arranged with their road-contacting tread surface extending substantially vertically, and are interconnected by a tread connecting device. The clearing device further exhibits tow means to enable towing by a vehicle, e.g. a tractor.

In accordance with the invention, the tread connecting device is realized in the form of two or more, substantially stiff, struts or steel bars extending through holes in the treads. A first end of the respective strut is releasable attached to an elongate frame, preferably metallic. The tow means is advantageously attached to the frame. A second end of the respective strut is provided with fastening means arranged to tighten the interconnected tire treads between the frame and the fastening means. In this way a substantially bending-stiff block of interconnected treads can be formed.

Moreover, the frame is provided with an elongate grader blade arranged along the elongate frame. The grader blade exhibits one or two edges arranged to contact and clear a road or a forest fire line surface. The grader blade and the frame it is connected to, extend substantially laterally viewed in the direction of movement when being towed. However, the lateral orientation may be changed, if desired, by adjusting the tow means in relation to a vehicle towing the clearing device. The grader blade may be attached releasable to the frame, or may constitute a part of the frame itself. However, as described in further detail below, the grader blade is attached releasable to the frame and in a height-adjustable manner. Thus, the grader blade may be exchanged by another and may be height-adjusted in accordance with the particular need.

Fina I ly, the clearing device according to the invention exhibits a lift-connecting means connected to one or more struts. The lift-connecting means extends above the upper surface of the block of interconnected treads. One particular purpose of the lift-connecting means is to enable the clearing device to be lifted and moved in case the towing vehicle has become stuck at the end of a road where there is no space to turn the vehicle with the towed clearing device. In a case like this, the clearing device is released from the vehicle, whereupon the vehicle turns, with its front loader, lifts the clearing device by the lift-connecting means, and moves the clearing device to another location. Then, the vehicle may turn in the opposite direction, re-connect the tow means of the clearing device and drive in the opposite direction.

The edge(s) of the grader blade may be straight like a knife. In a preferred embodiment, the edge(s) are staggered forming fingers or teeth. The purpose of the fingers or teeth is to dislodge gravel, rocks, roots and other solid materials located under the surface of the road or fire line, prior to a levelling operation performed by the block of interconnected treads located behind the grader blade viewed in the towing direction.

A staggered edge may have numerous configurations, i.e. the distance between adjacent teeth, tooth width and tooth length may vary, e.g. with the consistency of the surface to be cleared and grader blade material. The design of the grader blade should be within the reach of a person ski Med in the art håving knowledge about the present disclosure and the condition of the road or fire gate to be cleared and further details about the staggered grader blade is therefore omitted here. However, in general a forest truck road would require a relatively coarse staggered grader blade, with long teeth or fingers that may dig deeper down into the road or surface and loosen roots and similar. A finely staggered grader blade håving relatively short teeth or fingers would not be applicable to such roads, and would leave roots and similar in the ground, whereupon the road or surface will become overgrown at an earlier point in time.

In a particularly preferred embodiment, the grader blade is arranged adjustable in relation to the frame, in a substantially vertical direction, by a level adjustment device. In this way, the grader blade may be adjusted and fixed at a desired elevation prior to use to conform to the nature of the surface being cleared.

In one embodiment, the fastening means is a threaded nut fastened to the second end of a strut which is provided with corresponding threads. A washer is arranged between the nut and the outermost tread in the block of interconnected treads to support the nut against the outermost tread.

In one embodiment, the lift-connecting means is realized in the form of four rings, e.g., a closed loop steel wire. The rings are attached pairwise to respective two struts, thus forming an imaginary square or rectangle. A different number of rings is of course also conceiveable, e.g., eight, thus forming an imaginary polygon. The rings extend above the upper surface of the block of interconnected treads, wherein wire is extending through the openings of the rings, thus forming a closed loop for engagement with a lifting means, e.g., the front loader of a tractor.

In one embodiment, the frame is formed by two separate frame parts, a first frame part and a second frame part. The frame parts are releasable interconnected by connecting means, thus forming a space therebetween in which the grader blade is arranged.

The level adjustment device mentioned above may be an elongate beam arranged vertically slideably between said first frame part and second frame part. In this embodiment, the grader blade is connected to the beam, so that both the grader blade and the beam are located in the space between the first and second frame part.

The design of the frame simplifies exchange of the grader blade, e.g., when the clearing device is going to be used on a road or fire line håving different surface consistency.

Moreover, the clearing device is in a particularly preferred embodiment designed symmetrically, thus enabling the clearing device to be turned up-side down when one side of the interconnected block of treads has become worn-out.

When both faces of the block has become worn-out, the deck treads may be replaced by new ones by releasing the nut and removing the washer, retracting the worn-out treads and inserting new treads, and then re-tightening the array of treads by tightening the nuts.

The clearing device in accordance with the present invention represents a substantial improvement compared to the prior art, and enables efficient clearing of roads and fire gates thanks to the features of a bending-stiff tread block, and grader blade arranged ahead of the tread block viewed in the towing direction. The grader blade will dislodge solid material under the road or terrain surface, whereupon the bending-stiff tread block will effect a thorough levelling of the surface. Further details and benefits will appear in the following.

Detailed description

The present invention is now described in further details with reference to drawings, which illustrates an embodiment of the invention, where

Fig. 1 illustrates a clearing device according to the invention in a top view,

Fig. 2 is a cross-section of the clearing device tåken through the line A-A in Fig. 1, and

Fig. 3 is a cross-section of the clearing device tåken through the line B-B in Fig. 2.

Fig. 1 illustrates the terrain surface clearing device according to the invention in a top view. The device comprises numerous tire treads arranged with their (road contacting) tread surface adjacent to each other. The treads may be excised from truck tires, but the invention is not limited to this. Tire treads from for example automobiles may also be used, but truck tires is preferred because of their size and weight. The tire tread arrangement forms a rectangular or square-like tread block. The tread block is at one side connected to a frame 1, 2. The frame is provided with numerous holes 13 to facilitate attachment of a tow device (not shown). The illustrated embodiment of the frame is described in further detail below. The tire treads 6 are interconnected, and connected to the frame 1, 2, by numerous struts or bars 4, e.g. steel bars, extending through holes (not shown) in the tire treads. One end of the bars 4 are connected to the frame 1, 2, whereas the opposite (free) end of the struts 4 are arranged with fastening means 5. Here the fastening means 5 is realized in the form of a threaded nut and a washer or support plate for the nut, where the free end of the strut 4 is provided with corresponding threads (not shown). Accordingly, the tread block can be tightened by the numerous struts 4 by the tightening the nut of the fastening means 5 to provide a substantially stiff tread block that will not conform to the terrain, such as rocks and elevations on a road. The number of struts and fastening means may vary by the dimensions of the clearing device. At least one strut 4 including fastening means 5 must be arranged at each side of the clearing device viewed in the driving direction of a vehicle towing the clearing device. The embodiment of the clearing device illustrated in Fig. 1 has a total of six struts distributed evenly along the lateral extension of the tread block. However, the number of struts may for example be three to eight, or even more. In the preferred embodiment, a number of six struts have been shown to be sufficient. An increasing number of struts will provide a more stiff tread block to withstand surface deviations in the terrain, and sustain its own weight when lifted, but will also contribute to the weight of the clearing device as a whole.

Still referring to Fig. 1, the assembled clearing device according to the invention is provided with lift-connecting means 7, 8 to enable lifting of the clearing device, e.g., by the forks of a front loader. In this embodiment, the lift-connecting means is realized in form of four rings 7, e.g. a steel wire, connected pairwise to respective two struts 4. The rings 7 are extending above the upper surface of the tread block. A wire 8 or similar is extending through the apertures of the respective rings 7, forming a closed loop above the upper surface of the tread block, under which loop the forks of a front loader may be inserted to enable lifting of the clearing device. It should be noted that the embodiment of the lift-connecting means described above is only one out of numerous alternatives. It is also conceivable to provide a frame connected to struts in the assembly, where the frame extends a distance above the surface of the tread block. Accordingly, a person skilled in the art will be able to provide alternative solutions håving an equivalent effect.

Fig. 2 illustrates a cross-section through the lines A-A in Fig. 1. In the illustrated embodiment the frame comprises two separate frame parts, a first frame part 1 and second frame part 2, extending laterally when viewed in the towing direction. The respective frame part 1 and 2 is a substantially square elongate straight tube, each tube provided with frame end plates 9 at each end. The frame end plates 9 are fixed to the tube, e.g. by welding. Each frame end plate 9 has a circumference larger than the circumference of the respective tube 1 and 2 and is provided with holes for accommodation of fastening bolts (not shown). A connector plate 10 (Fig. 1) provided with through holes corresponding to the holes in the respective frame end plates 9 is attached to said first and second by bolts as mentioned above, and interconnects said first and second frame part 1 and 2. The respective struts 4 are connected to the first frame part 1 (indicated by dotted lines). The interconnected frame parts 1 and 2 form a space therebetween.

Now referring to Fig. 2, a first and second angle iron 3a and 3 are attached to the lower and upper surface of the first frame part 1, respectively, viewed when the clearing device is resting upon a road. The angle irons 3a and 3 are attached with one angle part in flush with the front side (viewed in the driving direction of a vehicle towing the clearing device) to support an elevation adjustment device 12 as described below. The elevation adjustment device 12 is here realized in form of a square tube or beam, arranged slideably in the space between the interconnected frame parts 1 and 2. The elevation adjustment device is connected releasable to the first frame part 1 and is adjustable to the desired elevation. A longitudinal grader blade 11 is attached to the elevation adjustment device 12 håving a longitudinal (horizontal) extension which substantially equals the width of the tread block, and a vertical extension. In the assembled clearing device of the present invention, the grader blade extends substantially laterally in relation to the towing direction and along the frame parts 1, 2. In this embodiment, it should be mentioned that the angle irons 3a and 3 providing a vertical front (viewed in the towing direction) surface extension of the first frame represent an important feature by serving as a support for the elevation adjustment device and the accompanying grader blade and accommodates forces acting upon the grader blade from the ground during towing and clearing. It should be emphasized that the embodiment described above only is one out of many, and a person skilled in the art is expected to design different constructions of the frame and the height-adjustable grader blade, to provide the equivalent effect of height adjustability and simple exchange of the grader blade.

It should also be mentioned that the grader may exhibit edges at one or both long ends in different configurations: the grader blade may exhibit a staggered edge at one end and a straight blade-like edge at the other; a coarse-staggered edge at one end and a fine-staggered edge at the other. The grader blade is in the illustrated embodiment arranged with its blade surface extending vertically. However, depending on the design of the frame parts 1, 2, the grader blade may be tilted in one direction or the other.

Advantages

The present invention has several advantages to prior art clearing devices. The clearing device can be used conveniently even on narrow roads and enables a vehicle towing the clearing device to turn and drive in opposite direction in a simple manner. The clearing device of the present invention makes a thorough clearing and removes rocks, studs, roots and similar, in addition to levelling of the road surface, thanks to the surface levelling bending-stiff tread block and the grader blade arranged ahead of the tread block in the driving or towing direction. The present clearing also enables removal of bush from the road side. As mentioned above, the clearing device may be formed symmetrically, and the clearing device as a whole may simply be turned up-side down when one side or face of the tread block has become worn-out. Finally, the clearing device of the present invention makes it possible to perform clearing of roads and fire gates in a faster way than before. As a result, clearing may be performed more frequently, if desired. On the other hand, the more thorough clearing of surface by the present clearing device increases the time between maintenance, e.g. annually.

Numeral references

1, 2 frame

1 first fra me part

2 second frame part

3a first angle iron

3 second angle iron

4 strut, steel bar

5 fastening means: threaded nut and washer/support plate

6 tire tread

7, 8 lift-connecting means

7 ring

8 wire

9 frame end plate

10 connector plate

11 grader blade

12 elevation adjustment device

13 holes for attachment of tow device

Claims

1. Clearing device, suitable for clearing forest truck roads, farm roads and fire gates, said device comprising a block of interconnected tire treads (6) arranged with their road-contacting tread surface extending substantially vertically, said tire treads (6) being interconnected by a tread connecting device (4), said clearing device further exhibiting tow means to enable towing by a vehicle, a lift-connecting means extending above the upper surface of the block of interconnected treads (6), and a grader blade (11) with one or two edges arranged to contact and clear the surface to be cleared,characterized in that: the tread connecting device (4) are two or more struts (4) extending through holes in the treads (6), wherein a first end of the respective strut (4) is releasable attached to an elongate frame (1, 2) exhibiting said tow means, and a second end of the respective strut (4) is provided with fastening means (5) arranged to tighten the interconnected tire treads (6) between the frame (1, 2) and the fastening means (5), thus forming a substantially bending-stiff block of interconnected treads (6), wherein the lift-connecting means (7, 8) is connected to one or more struts (4), and said frame (1, 2) exhibits the elongate grader blade (11) arranged along the elongate frame (1, 2).

2. The clearing device of claim 1,characterized in thatsaid one or two edges of the grader blade (11) are straight like a knife, or that one or two edges is/are staggered forming fingers or teeth, or that one edge is straight and that the other edge is staggered.

3. The clearing device of claim 1 or 2,characterized in thatthe grader blade (11) is arranged adjustable in relation to the frame (1, 2), in a substantially vertical direction, by a level adjustment device (12).

4. The clearing device of claim 1,characterized in thatthe fastening means (5) is a threaded nut fastened to the second end of the strut (4) which is provided with corresponding threads, wherein a washer is arranged between the nut and the outermost tread (6) in the block of interconnected treads (6).

5. The clearing device of claim 1,characterized in thatthe lift-connecting means is four or more rings (7) attached pairwise to respective two struts (4), thus forming an imaginary square or rectangle or polygon, said rings (7) extending above the upper surface of the block of interconnected treads (6), wherein a wire (8) is extending through the openings of the rings (7), thus forming a closed loop for engagement with a lifting means.

6. The clearing device of any one of claim 1 to 3,characterized in thatthe frame (1, 2) is formed by two separate frame parts, a first frame part (1) and second frame part (2), said frame parts being releasable interconnected by connecting means (9, 10), thus forming a space therebetween, wherein the grader blade (11) is arranged in the space between said first (1) and second (2) frame part.

7. The clearing device of claim 3 or 6,characterized in thatthe level adjustment device (12) is an elongate beam arranged vertically slideably between said first frame part (1) and second frame part (2), wherein the grader blade (11) is connected to the beam (12), so that both the grader blade (11) and the beam (12) are located in said space between the first (1) and second (2) frame part.

8. The clearing device of any one of claim 1 to 7,characterized in thatthe clearing device is designed symmetrically, thus enabling the clearing device to be turned up-side down when one side of the interconnected block of treads (6) has become worn-out.