BACKGROUND ART The need to deposit abrasive material in front of traction wheels of vehicles has long existed in order to improve road safety during inclement winter weather conditions. Many attempts have been made to develop such system but none to date have proved to be viable for various reasons such as being reliable, easily adaptable to vehicles, being substantially maintenance free and providing ease of access to the system for loading abrasive particles in a reservoir associated with a dispenser. Also, the abrasive materials usually consist of sand and/or salt, and such materials have also proven to be unreliable due to the fact that humidity sets in to these materials, causing it to bind together and clog up the dispensing mechanism or prevent the particles from flowing out of the reservoir. In order to overcome these disadvantages, some systems have incorporated with the reservoir, heating elements whereby to heat the reservoir to prevent its content from freezing. Others have used vibrators to stir up the material in the reservoir, and this has rendered these systems bulky, expensive and more apt to malfunction.

Particular reference is made to U. S. patent No. 5,580, 106 which uses compressed air, as with the present invention, in order to convect an abrasive material, herein sand, from a reservoir into a conduit and convey it to a discharge outlet which is located in front of the traction wheels of a vehicle. The pressure conduit is located under the reservoir and is in communication with a gravity flow pipe, wherein sand is discharged into the conduit. The gravity flow pipe is of a fixed diameter. The reservoir is a sealed reservoir and some of the pressurized air is allowed to enter the reservoir through the discharge orifice. In order to do so, it is necessary that the reservoir not be sealed at the top so that air can flow into the reservoir. Allegedly,

this air is intended to create a down pressure to help in expelling sand from the reservoir. However, because the storage compartment or reservoir is bounded by walls and sealed, the system cannot operate as described and sand will tend to form into solid chunks with the infiltration of humidity. A further disadvantage of this system is that the pipes are curved upwardly, creating pockets in which the sand particles can be trapped and again clog the discharge conduit as well as the discharge outlet and rendering this system inoperative. Accordingly, the system as described in this patent has not been found reliable and is prone to too many malfunctions.

SUMMARY OF INVENTION It is a feature of the present invention to provide an abrasive material distribution system for the depositing a hard abrasive material mixture on a road surface in front of at least some of the traction wheels of a motorized vehicle, and which substantially overcomes the above-mentioned disadvantages of a prior art.

According to the above features, for a broad aspect, the present invention provides an abrasive material distribution system for depositing a hard abrasive material mixture on a road surface in front of at least some of the traction wheels of a motorized vehicle. The system comprises at least two reservoirs, each having an automatically closable opening for loading abrasive material therein. The abrasive material has been substantially cleaned of foreign matter capable of retaining humidity. A dispensing chamber is provided at a bottom end of each of the reservoirs and is in communication with the abrasive material therein. A discharge outlet is provided in a sidewall of the dispensing chamber and spaced from a bottom wall of the dispensing chamber. An ejector nozzle is adjustably disposed in the dispensing chamber in the abrasive material and in aligned spaced relationship with the discharge outlet. The ejector nozzle is connected by conduits to a compressed air reservoir. A valve is provided in the conduits to supply compressed air to the ejector nozzle. The discharge outlet has distribution conduit means connected thereto and to dispensing outlets secured at predetermined locations in front of the traction wheels. Control means is provided to actuate the valve to conduct or shut off compressed air to the ejector nozzle to transport the abrasive material to the dispensing outlets, and to be ejected therefrom.

BRIEF DESCRIPTION OF DRAWINGS A preferred embodiment of the present invention will now be described with reference to the accompanying drawings in which: Figure 1 is a schematic illustration of a motorized vehicle equipped with the abrasive material system of the present invention; Figure 2 is a fragmented section view showing the construction of the reservoir and its dispensing chamber secured at the bottom end thereof ; Figure 3 is an enlarged view of the dispensing chamber showing the position of the ejector and its adjustability with respect to a discharge outlet thereof; Figure 4 is a top view of figure 3.

Figure 5 is an enlarged view of the ejector and its position relative to the discharge outlet; and Figure 6 is a schematic illustration of a complete system which is controllable from the driver position of a motorized vehicle, such as a tractor trailer.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring to the drawings, more particularly to figure 1, there is shown generally at 10 a motorized vehicle such as the tractor of a tractor trailer type vehicle.

As herein shown, the tractor is provided with reservoirs 11, only one being shown herein, each associated with one of four traction wheels 12, only two shown herein, of the tractor 10. The reservoirs 11 are loaded with a hard rock material mixture 13, which is deposited on a road surface 14 through convection conduits 15.

An important feature of the present invention is that the abrasive particle material mixture 13 is a composition of quarry rock particles and contains predetermined quantities of three average group sizes of these rock particles. These particles do not disintegrate when subjected to the pressure load of the vehicle. One of the groups contains particles of average diameter of approximately 1/16 of an inch, the other of approximately 1/8 of an inch, and a third of approximately 3/16 of an inch. It has been found that with this mixture, there is good-adherence to an icy surface forming on the road surface 14, and because these particles can be heated, as will be described later, the larger particles tend to grasp quickly into the icy surface and contact the pavement underneath to provide excellent traction. The smaller

particles also adhere quickly to the icy surface, but do not have the same effect as the larger particles which cause the icy surface to break up. Washed mortar sand has also been found to work satisfactorily but preferably the quarry rock mixture has been found to be the best abrasive material for this purpose.

A dispensing chamber 16 is secured under each of the reservoirs 11 to convect predetermined quantities of abrasive material through the convection conduits 15, and out through the discharge outlets 17 thereof.

Referring now to figures 2 to 5, there will be described the construction and operation of the reservoir 11 and its dispensing chamber 16. As shown on figures 1 and 2, the reservoir can be an elongated vertically supported reservoir containing a large quantity of abrasive material therein. However, when the system is applied to small road vehicles, the reservoirs are much smaller not to take too much space in the vehicles. It is also pointed out that these reservoirs, when loaded with abrasive particles, also provide additional weight, usually in front of the traction wheels, to improve the traction of the vehicle with the road surface. The reservoir 11 has a top opening 18 through which the abrasive material 13 is loaded. A cover 19 hermetically seals the reservoir 11. The dispensing chamber 16 is secured by fasteners 20 to an open bottom end 21 of the reservoir 11, and an appropriate sealing- gasket 22 is interposed between the connecting flange walls 21'of the reservoir and 16'of the dispensing chamber 16. Accordingly, the abrasive material 13 within the reservoir 11 enters the dispensing chamber 16 and contained throughout the chamber down to its bottom wall 23.

With specific reference to figures 3 to 5, there is more clearly illustrated the construction operation of the dispensing chamber 16. As therein shown, the dispensing chamber is provided with a fixed discharge outlet pipe 25 provided in a side wall 26 of the chamber and spaced above the bottom wall 23 thereof. An ejector nozzle 27 is secured to a support housing 28, and has an extension portion 30 which projects through the side wall 26 through a sealing coupling 29 to prevent air from escaping therethrough, while permitting the ejector nozzle extension portion 30 to' move axially through the sealing coupling 29, whereby to adjust the portion of the ejector end 31 of the ejector nozzle 27 relative to the discharge outlet pipe 25. The

ejector is elevated from the bottom wall, and therefore is located within the abrasive mixture.

The support housing 28 is provided with an electric motor 32, which is provided with a pinion gear 33 on the outlet shaft 34 thereof, and the gear 33 is in toothed engagement with a toothed rack 35 secured to the end portion of the extension portion 30 of the ejector nozzle 27. The convection conduit 15 connects to the outer free end 36 of the extension portion 30 outside the support housing 28. Accordingly, the position of the nozzle can be remotely adjusted whereby to vary the distance of the gap 49 between the ejector end 31 and the discharge outlet 25 to control the rate of abrasive material being discharged.

As shown in figures 3 and 4, the dispensing chamber 16 is provided with resistive heating elements 40 to heat the abrasive material mixture 13 located within the dispensing chamber at the bottom end of the reservoir. Accordingly, it is not necessary to heat all of the abrasive material, seeing that the abrasive material mixture is substantially cleaned of any foreign matter which is capable of retaining humidity.

This substantially eliminates the formation of chunking of the abrasive material as there is no foreign matter to absorb humidity.

As shown, the ejector nozzle 27 has at least one ejector opening 41 at the ejector end 31 thereof, and disposed in facial alignment and substantially central with the discharge outlet pipe 25. The ejector opening 41 is spaced at a predetermined distance from the discharge outlet pipe 25 as a function of the size of abrasive particles being used and the rate to be discharged over a predetermined period of time that the compressed air is connected to the ejector nozzle. There are preferably two or three of these ejector openings with ejector opening 41 being aligned centrally and ejector openings 42 and 43 being disposed offset from the central axis 45 of the ejector nozzle 27, whereby some of the particles 13 will be ejected in the conduit 15 secured to the discharge outlet 25 at an angle, as illustrated by arrows 43'and 42' respectively, to create a spiral movement 44 within the outlet conduit pipe 25 and conduit 15 or at least along a section thereof, whereby to maintain the particles in mixture.

As shown in figure 5, the ejector nozzle 27 is further provided with at least one material mixing orifice 46 and preferably two orifices 46 and 46', which are

disposed at opposed angles from one another to create a rotational stirring motion inside the dispensing chamber 16 on the inner surface 16"thereof. The cylindrical inner surface or sidewall 16", due to its curvature, provides uninterrupted stirring action. Arrows 47 and 47'show the direction of these ejector nozzles or orifices, which stir the particles inside the dispensing chamber.

As shown in figure 5, the discharge outlet 25 is constituted by an inlet end 25' of the pipe coupling 25", which extends inside the dispensing chamber and this inlet end is tapered, as shown at 25', whereby to define a bottom lip 48 at a bottom end of the tapered inlet to support some of the abrasive material mixture in a portion of the discharge gap 49 defined between the ejector openings 41,42 and 43, and the tapered inlet end 25'. The tapered inlet end also provides an enlargement end for receiving the abrasive particle material from the reservoir. The convection conduit 15 connects to this pipe coupling 25 in a well known manner.

With reference to figure 6, there is shown a complete abrasive material distribution system 75 such as the one adapted to the tractor vehicle 10, as illustrated in figure 1. It consists of four reservoirs 11, which are filled with the abrasive material and a compressed air reservoir 55 which is connected to a compressor 56.

The compressor 56 is connected by an electrical connection 56'to the control unit 57, which is located in the cab portion 58 of the tractor vehicle 10. A pressure regulator 59 regulates the pressure within the reservoir 55 and maintains it to at least 20 p. s. i. and preferably approximately 40 p. s. i. The pressure line 39 is connected to each ejector 27 associated with each reservoir 11 via a remotely actuable valve 60.

The control unit 57 is provided with an on and off switch 61 to actuate the system and a further switch 62 to actuate the resistive heating elements. The control unit also connects to the brake pedal 63 of the vehicle which is provided with a brake switch 64, and the control unit is provided with four individual switches 65 associated with each of the dispensers. These four switches 65 are each associated with the dispensing units of each of the four traction wheels of the vehicle, as indicated by the pictorial illustration 66 provided on the control unit. If the switches 65 are switched to the automatic mode, then each time the brake pedal 63 is depressed, the dispensing unit will dispense the abrasive material in front of its associated traction wheels.

Accordingly, the conductor of the vehicle can engage the dispensers associated with

any of the four traction wheels or all the traction wheels by positioning the switch to an automatic mode 67. If the switches are placed to a manual mode, then the conductor must manually actuate these switches when he wants to dispense abrasive material. The manual mode is indicated at 68. The switch 71 operates the motor 33 to control the gap size 49.

The control unit is also provided with indicating lights 69 which are of different colors, whereby to indicate the quantity of abrasive material remaining in the reservoirs. The lights are actuated by level detectors 72,72'and 72"secured to the reservoirs 11. The control unit 57 is also connected to the battery 70 of the vehicle to provide the necessary 12 volts supply for the compressor, light indicators and other electrical wiring of the system, as is necessary.

It is within the aim of the present invention to cover any obvious modifications of the preferred embodiment described herein, provided such modifications fall within the scope of the appended claims. For example, as shown in figure 2, the dispensing chamber 16 may be a conically shaped chamber 16"'with the material mixing orifices 20 or nozzles 46 and 46'being aligned tangentially with the inner surface of the side wall of the conical chamber. All of the conduits may also be either flexible or rigid conduits.