|
(11) | EP 1 285 998 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
|
|
|
|
|||||||||||||||||||||||
| (54) | Device for spreading salt |
(57) The invention relates to a device for spreading salt, which device comprises:
the loosening means are drivable and make a substantially linear movement directed transversely of the transport direction. |
[0001] The invention relates to a device for spreading salt, which device comprises:
- a supply container for the salt,
- transport means arranged under the supply container for transporting a layer of salt from the supply container to a discharge area;
- spreading means placed under the discharge area of the transport means for spreading the salt; and
- loosening means for loosening the layer of salt in the discharge area.
[0002] When spreading salt to combat icy roads it is important that a constant quantity of salt per square metre comes to lie on the road surface. In already known spreading devices the width of the spreading stream can therefore be adjusted, and the quantity of salt per square metre. These parameters then depend on the speed of the vehicle on which the device is placed. The speed of the transport means for transporting the salt from the supply container to the spreading means is usually related to the vehicle speed.
[0003] At low speeds of up to about 40 km/hour the problem can however occur that the salt is not distributed uniformly over the road surface. This can occur particularly in the case of salt with a high moisture percentage.
[0004] It has been found that this irregular distribution occurs because the layer of salt transported out of the supply container has a certain cohesion, whereby at low speed large pieces of this layer break off in the discharge area, whereby the supply of salt to the spreading device becomes irregular.
[0005] It is known to place in the discharge area of the transport means a number of chains which break the layer of salt. Such a modification does not however work adequately at low speed and at a low concentration of salt per square metre. At these low concentrations quantities of up to 10 gr/m2 are envisaged.
[0006] It is an object of the invention to provide a device with which a uniform distribution of the salt over the road surface can be obtained at low speed and with low quantities of salt per square metre.
[0007] This object is achieved with a device according to the invention which is characterized in that the loosening means are drivable and make a substantially linear movement directed transversely of the transport direction.
[0008] The loosening means thus exert a force at a right angle to the transporting direction of the salt, whereby the cohesion of the layer of salt is broken and whereby a uniform quantity of salt falls into the spreading means, whereby a uniform distribution of the salt over the road surface is obtained.
[0009] The linear movement is preferably a reciprocal movement. This prevents the distribution of the salt becoming asymmetrical in the flow toward the spreading means, whereby an asymmetrical distribution of the salt over the road surface would be obtained.
[0010] In a preferred embodiment of the device according to the invention the frequency of the reciprocal movement lies in the range of 30 to 130 strokes per minute. In particular, the frequency is about 80 strokes per minute. It has been found that at such a frequency the layer of salt is loosened sufficiently to obtain a uniform distribution of the salt over the road surface at very low speeds of up to about 40 km/hour, wherein the quantity of salt per square metre is not higher than about 10 gr/m2.
[0011] In another preferred embodiment according to the invention the loosening means comprise a number of protrusions extending through the layers of salt. These protrusions can for instance be pin-like or chains.
[0012] With such protrusions it is recommended that the protrusions are arranged at a fixed relative pitch and the stroke of the reciprocal movement is larger than the pitch. This ensures that the protrusions reach over the whole cross-section of the layer of salt and thus loosen it.
[0014] In yet another embodiment of the device according to the invention the spreading means are provided with a coating. It has been found that the salt does not adhere to a coated surface, so that the loosened salt is distributed immediately by the spreading means and does not adhere in the spreading means, whereby a non-uniform distribution could again result.
[0015] These and other features of the invention are further elucidated with reference to the annexed drawings.
[0016] Figure 1 shows a vehicle having thereon an embodiment of the device according to the invention.
[0017] Figure 2 shows in schematic perspective view the loosening means of a device according to the invention.
[0019] This device 2 has a supply container 3 for salt 4. A conveyor belt 5 is arranged on the underside of this supply container 3.
[0020] Arranged in supply container 3 is a valve 6 with which the thickness of the layer of salt 4 on conveyor belt 5 can be adjusted. At the end of conveyor belt 5, in the discharge area, are arranged loosening means 7 which will be further elucidated hereinbelow with reference to figure 2.
[0021] Arranged under the discharge area of conveyor belt 5 is a collecting plate 8 which collects the salt 4 falling from conveyor belt 5 and carries it to spreading plate 9. This spreading plate 9 is driven by a motor 17 so that salt 4 is spread over the road surface in a fan shape.
[0022] Figure 2 shows the loosening means 7 in further detail. These loosening means 7 consist of a horizontal rod 10 which is guided by one or more guides 11. These guides 11 ensure that horizontal rod 10 can be moved reciprocally as according to arrow R.
[0023] Arranged on the underside of rod 10 are a number of pins 12 which extend along the reversing roller 13 of conveyor belt 5 and thus extend through the layer of salt 14. Horizontal rod 10 is coupled to a motor 16 by means of a linkage 15. By driving this motor 16 the linkage 15 ensures that horizontal rod 10 makes a reciprocal movement. Pins 12 hereby make a substantially linear movement directed transversely of the direction of transport, whereby the layer of salt 14 is scraped off and the salt can fall uniformly distributed into collecting plate 8.
1. Device for spreading salt, which device comprises:
the loosening means are drivable and make a substantially linear movement directed transversely of the transport direction.
- a supply container for the salt,
- transport means arranged under the supply container for transporting a layer of salt from the supply container to a discharge area;
- spreading means placed under the discharge area of the transport means for spreading the salt; and
- loosening means for loosening the layer of salt in the discharge area,
characterized in thatthe loosening means are drivable and make a substantially linear movement directed transversely of the transport direction.
2. Device as claimed in claim 1, wherein the linear movement is a reciprocal movement.
3. Device as claimed in claim 2, wherein the frequency of the reciprocal movement lies
in the range of 30 to 130 strokes per minute.
4. Device as claimed in any of the foregoing claims, wherein the loosening means comprise
a number of protrusions extending through the layers of salt.
5. Device as claimed in claim 4, wherein the protrusions are arranged at a fixed relative
pitch and wherein the stroke of the reciprocal movement is larger than the pitch.
6. Device as claimed in claim 4 or 5, wherein the protrusions are pin-like.
7. Device as claimed in claim 4 or 5, wherein the protrusions comprise chains.
8. Device as claimed in any of the foregoing claims, wherein the loosening means are
driven by a hydraulic and/or an electric motor.
9. Device as claimed in any of the foregoing claims, wherein the spreading means are
provided with a coating for reducing the adhesion of salt to the spreading means.