Abstract:
A system for applying particulate materials comprising a supply source of pressurized gas, a chamber with first and second opposed side walls, at least one pressurized gas entrance conduit for transporting pressurized gas to the chamber, at least one material hopper for depositing particulate material into the chamber, and at least one pressurized gas exit conduit for transporting particulate material away from the chamber. The wand is flexible and is manually controlled so that the user can control the exact direction in which the particulate material is to be focused. The wand includes a switch which sends a signal to a signal-actuated valve which is coupled to the entrance conduit. Upon receiving the appropriate signal, the signal-actuated valve adjusts so as to alter the flow of particulate material. The apparatus is powered by a motor source which maintains an optimum pressure range inside the entrance conduit through the use of a feedback loop operating between the motor source, the compressor, a pressure valve and a throttle. The apparatus is of the appropriate size so as to be mounted on a vehicle.

Description:
This application is a continuation-in-part of U.S. patent application Ser. No. 09/422,216, filed on Oct. 19, 1999 now patented as U.S. Pat. No. 6,343,897. 
    
    
     TECHNICAL FIELD 
     This invention relates generally to systems for spreading particulate materials. More particularly, this invention relates to a system for spreading particular amounts of particulate materials in an even manner across different surfaces. 
     BACKGROUND OF THE INVENTION 
     There are several devices currently known to the landscaping industry which perform an effective job of distributing particulate materials across open spaces such as grass fields. One such device comprises a hopper with a rotary vane attached underneath that can spread particulate materials in all directions as the hopper is pushed forward or backward. Although such devices are adequate for wide-open spaces, they have several shortcomings in other situations. For example, there is often a need to spread fertilizer, pesticides, or other materials along the underside of shrubbery or garden plants. Because concentrated fertilizer can be corrosive and can damage plant tissue because of chemical burning, there is a need for a way to uniformly apply fertilizer below the leaves of the plants while avoiding placing any fertilizer on top of the leaves. Because common hopper-type spreaders cannot perform this task adequately, landscape maintenance workers often have to perform this task by hand by dipping a cup or other container into a hopper or bag and then distribute the material by hand to the underside of the shrubbery. This process can be very cumbersome and time-consuming, and it is very difficult to guarantee that the particulate materials are evenly distributed over the intended surfaces. When a worker uses this process, some areas will often get no particulate material at all, while other areas will get too much material. Additionally, if the worker is not careful or is in a hurry, fertilizer could accidentally be thrown onto the leaves of the plant, causing serious damage to the plant. Finally, distributing the fertilizer by hand can cause the worker to accidentally spill material upon himself, which can create an unprofessional image of the worker or pose health risks depending upon the composition of the fertilizer. 
     Similar problems exist for other particulate materials. For example, it is often desirable to evenly distribute grass seed in corners or hard-to-reach areas of a plot of land. Additionally, it can also be important to distribute salt or urea on icy and snowy pavement or sidewalk during the winter months. Although there are several products currently on the market that perform an adequate job of distributing these materials along roads, these devices often have a difficult time reaching non-flat, paved areas such as steps or corners. If the salt or urea is not adequately distributed on such surfaces, portions of the surfaces can remain icy and slippery and could result in serious harm to someone who walks on the surfaces. As in the case of the landscape maintenance worker, people often spread the materials by hand to reach difficult places. But this can be very time-consuming and it is difficult to ensure that the material is evenly spread across the surfaces. 
     There are still other areas where there is a need for evenly spreading particulate materials while maintaining precise control of where the materials are deposited. For example, golf course maintenance personnel often need to spread dry sand in sand traps and other areas. In these situations, a user&#39;s options are often quite limited in how they can efficiently and adequately spread the materials in an even manner. 
     It is also important that a person who is spreading particulate materials can do so over a large area quickly and efficiently. In the case of a large plot of land, a worker must often spread particulate materials in many different locations in hard to reach areas. 
     There have been attempts to develop systems for spreading particulate materials in an even manner, but each has its drawbacks. In particular, several devices use a combination of a rotary vane and a blower motor to power the spreader through a large boom. Blower motors are an inefficient means of forcing air at a velocity sufficient to force the particulate materials out of the boom, however, and such systems would require air hoses with a diameter of about two to four inches. These devices can also be so large and heavy that they must be mounted in the bed of a compact pick-up truck in order to be transported. Furthermore, the exit channels on many of these devices are fixed in position relative to the rest of the device and have a limited range direction when spreading the materials. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of this invention to provide an improved system for spreading particulate materials across surfaces in an evenly-distributed manner. 
     It is another object of this invention to provide an improved system for spreading particulate materials in which the user can precisely control the direction in which the materials are spread. 
     It is another object of this invention to provide a system for spreading particulate materials that can be adapted to spread materials of different densities and particle sizes. 
     It is yet another object of this invention to provide a vehicle-mounted system for spreading particulate materials. 
     It is yet another object of this invention to provide an system for spreading particulate materials that can spread the materials in more than one direction at one time. 
     It is yet another object of this invention to provide a system for applying particulate materials wherein the user has the ability to quickly activate or discontinue the flow of the particulate material. 
     It is yet another object of this invention to provide a system for spreading particulate materials wherein the amount of material that is distributed can be quickly adjusted. 
     It is yet another object of this invention to provide a system for spreading particulate materials wherein the system can make adjustments to ensure that a constant amount of material is being distributed over time. 
     It is still another object of this invention to provide a system for spreading particulate materials wherein the apparatus can be easily operated. 
     To obtain the above-described objects, one aspect of this invention provides for a particulate spreader comprising an engine which supplies energy to a compressor. The compressor compresses air or other compressible fluid in a pressurized supply source, and the pressurized gas flows from the supply source into a chamber or metering block through a pressurized gas entrance conduit. At the same time, particulate material from a material hopper is deposited into the metering block. The particulate material is carried or entrained by the pressurized gas into an exit conduit, preferably in the form of a flexible hose with a wand at the end thereof. Both the air flow and the flow of particulate material can be modified by manually adjusting a series of valves. The preferred engine-compressor combination includes a feedback loop for maintaining the air pressure within a certain range. A user holds the exit conduit at a handle and points the wand in the appropriate direction and activates a switch in the handle for starting the flow of gaseous material to the metering block, spreading the particulate material in the desired location. The user also operates the switch when it is desired to stop the spreading operation by discontinuing the flow of air into the metering block. The switch and valve can also be modified to maintain a partial flow of air into the metering block. 
     According to another aspect of the invention, one engine and one compressor are used to supply compressed air to two separate metering blocks. Each metering block has an exit conduit connected to it so that particulate materials can be spread in multiple directions at one time. 
     These and other objects, advantages, and features of the invention, together with the organization and manner of operation thereof, will become apparent from the following detailed description when taken in conjunction with the accompanying drawings, wherein like elements have like characters throughout the drawings described below. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an isometric view of apparatus for spreading particulate materials; 
     FIG. 2 is a side view of the apparatus shown in FIG. 1, more particularly showing the components that make up the mixing and distribution of the particulate materials; 
     FIG. 3 is a side view of the metering block in conformance with one embodiment of the invention; 
     FIG. 4 is a pneumatic and electrical system diagram of the flow of the pressurized gas from the air tank to the metering block and the electrical circuit for actuating the system by using the handle-mounted switch; 
     FIG. 5 a  is a side view of a system for spreading particulate materials wherein material can be spread in multiple directions; 
     FIG. 5 b  is a side view of an alternate system for spreading particulate materials wherein material can be spread in multiple directions; 
     FIG. 6 is a side view of an alternative embodiment of the invention wherein two concentrically-positioned material hoppers are used to spread different types of materials, a second and internally-disposed one of the hoppers being shown in phantom; and 
     FIG. 7 is a sectional side view of a metering assembly according to an alternate embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As can be seen in FIGS. 1 and 2, a particulate spreader indicated generally at  20  comprises a chamber or metering block  22  with a pressurized gas entrance conduit  24  and an exit conduit  26  connected thereto. A material hopper  28  is located generally above the metering block  22  and includes a passage  30  that runs from the bottom of the material hopper  28  to the top of the metering block  22 . Preferably, the passage  30  is gravity-fed with particulate material from the material hopper  28 . In one embodiment of the invention, the channel  30  includes a valve  32  for adjusting the amount of particulate or particulate material that enters the metering block  22 . In a most preferred embodiment of the invention, the valve  32  on the channel  30  is a standard ball valve. 
     Referring to FIG. 3, the air entrance conduit  24  includes an air nozzle  54  which protrudes through a first wall  34  of the metering block  22  by a predetermined distance d. In a preferred embodiment of the invention, the nozzle  54  has an exit diameter  55  of about one-eighth of an inch. As shown in FIG. 4, the pressurized gas entrance conduit  24  runs from the metering block  22  back to an air tank  36 . In the illustrated embodiment of the invention, the pressurized gas entrance conduit  24  is in the form of an air hose and has a diameter of about three-eighths of an inch. The air inside the air tank  36  and the pressurized gas entrance conduit  24  is compressed by a compressor  38  which is connected to the air tank  36  by an air supply line  40 . Also connecting the compressor  38  to the air tank  36  is a second pressure line  98 . Communicating with the air tank  36  on the entrance conduit  24  is a regulator  42 , which is connected to the air tank  36  via an intermediary conduit  96 . Communicating between the compressor  38  and the air tank  36  is an unloader  92 . A pressure gauge  94  is also attached to the air tank  36  so that a user can visually monitor the air pressure inside the air tank  36 . The unloader  92  is preset for a standard operating range. The compressor  38  is connected by a transmission link  43  to a prime mover such as a motor or a preferably gasoline-driven internal combustion engine  44 . The engine  44  can be the same as the engine used by a vehicle upon which the spreader  20  is mounted (FIG.  1 ), or the engine  44  can be dedicated to supply power to the spreader  20  alone. A throttle  46  is coupled to the engine  44 . The compressor  38  and the engine  44  are connected to each other by a first pressure line  70  and by the transmission link  43  which is used by the engine  44  to supply power to the compressor  38 . The power transmission link drive train  43  can take the form of a drive shaft, belt, a hydraulic line, gearing, or a more complicated transmission. 
     Referring to FIGS. 2 and 3, the exit conduit  26  is in the form of a flexible hose  48 . The hose  48  is connected to the metering block  22  by a hose disconnect  50  at a second wall  52  of the chamber. The hose  48  can be any of several lengths and preferably has a diameter of about one inch. The length of hose  48  is selected to be long enough for a user on foot to use it comfortably, supposing that the spreader  20  is mounted on a vehicle, but not so long that significant reductions of pressure and velocity result. The user can also employ the flexible hose while riding in or driving the vehicle. A wand  58  terminates the hose  48 , and can be pointed in virtually any direction by the user in order to precisely direct the flow of particulate materials to the areas where they are wanted. A handle  60  is mounted on the hose  48  near its end and includes an electrical switch  62  for adjusting the air flow in the spreader  20 . 
     As seen in FIG. 4, the switch  62  is electrically connected to an electrically-actuated valve  64  which is coupled to the entrance conduit  24 . The switch  62  is capable of being placed in at least two positions. In the illustrated embodiment of the invention, the electrically-actuated valve  64  is in the form of a solenoid valve which can either completely open or close the entrance conduit  24 , either permitting or restricting the movement of air to the metering block  22 . In an alternative embodiment of the invention, the electrically-actuated valve can have three or more positions such that when the position of the switch  62  is adjusted, a signal is sent to the electrically-actuated valve  64 , which in turn adjusts its position to either permit more or less air to pass through the entrance conduit  24 . The switch  62  selectively connects the electrically-actuated valve  64  to a battery  68 . In a preferred embodiment of the invention, the battery  68  is capable of producing a current of about three amperes at twelve volts DC. 
     The air flow to the metering block  22  can also be manually controlled by adjusting a ball valve  25  (FIGS. 2 and 4) located along the pressurized gas entrance conduit  24 . In one embodiment of the invention, the ball valve  25  acts as an emergency shut-off for the spreader  20 . 
     The operation of the spreader is as follows. The engine  44  is used to power the compressor  38 . The compressor  38  works to compress the air inside the air tank  36 . In order to adequately operate the electrically-actuated valve  64  (when, as preferred, it is a solenoid valve), the compressor  38  should compress the air in the air entrance conduit  24  to about fifty pounds per square inch. In a preferred embodiment of the invention, the pressure in the air entrance conduit  24  is regulated to be in the range of sixty to ninety pounds per square inch. 
     In order to maintain the appropriate pressure in the air entrance conduit  24  at this range, the pressure generated in the air tank should remain in the range of about 100 to 115 pounds per square inch. To maintain the pressure in this range, the pressure gauge  56  and the unloader  92  monitor the air pressure. When the pressure exceeds about 115 pounds per square inch in the pressure gauge  56 , the unloader  92  closes the first pressure line  70  running between the compressor  38  and the engine  44 . The closure of the first pressure line  70  results in a closing of the throttle  46 . The closing of the throttle  46  powers down the engine  44 , in one embodiment of the invention, preventing the compressor  38  from forcing additional air into the air tank  36 . Similarly, when the pressure in the air tank falls below about 80 pounds per square inch, in one embodiment of the invention, this will be sensed by the pressure gauge  56 , giving the user a visual indication of the pressure. The unloader  92  opens the first pressure line  70  running between the compressor  38  and the energize  44 . This also opens the throttle  46  (FIG.  2 ), which powers up the engine  44 . Additional power is then applied to the compressor  38  in order to increase the pressure in the air tank  36 . 
     Referring in particular to FIGS. 2 and 3, when the air inside the air tank  36  is under the appropriate pressure and the ball valve  25  is at least partially open, compressed air is forced into the metering block  22 . By opening the valve  32  between the material hopper  28  and the metering block  22 , particulate material is permitted to fall into the metering block  22 . In preferred embodiment of this invention, the particulate material can be salt, sand, fertilizer, pesticide, herbicide, urea, or grass or other seed, although other materials are possible so long as the materials are not so thick or sticky as to clog up the inside of the channel  30  or the metering block  22 . One advantage of the invention is that the air pressure and particulate feed flow can be adjusted for different particulate or particulate materials. The density and therefore the fluid-entrainment characteristics will vary greatly among these various kinds of solid particulates; less air mass is needed to push grass seed than, for example, quartzite sand. As the particulate material falls into the metering block  22 , it carried by the air stream flowing out of the nozzle  54  into the exit conduit  26 . 
     In order to ensure to that substantially all of the particulate material is transported into the exit conduit  26 , the location of the end of the nozzle  54  relative to the second wall  52  is important. Preferably, the open end of the nozzle  54  should be positioned at a distance d which is between one-half and three-fourths of the width w, taken between the first wall  34  and the second wall  52 . In a most preferred embodiment of the invention, the end of the nozzle  54  is positioned about five-eighths of the way across the metering block  22  to the second wall  52 . In one preferred embodiment of the invention, the distance from the first wall  34  to the second wall  52  is about 2.2 inches. The end of the nozzle  54  is substantially coaxial with the exit conduit  26 . 
     As the particulate or granular materials interact with the air stream coming from the nozzle  54 , they are transported through the hose  48  to the wand  58 . The user holds the wand  58  by the handle  60  and points the wand  58  in the desired direction. When the switch  62  is in a position in which at least some air is flowing through the entrance conduit  24 , the particulate materials will be forced out of the wand  58  and the particulate materials will be spread in the desired direction. In a preferred embodiment of the invention where fertilizer is used as the particulate material, between about six and a half and seventeen pounds of material should be spread per minute, although this amount can be easily adjusted by adjusting the regulator  42 , the valve  32  below the material hopper, or adjusting the switch  62  on the handle  60  if the switch  62  has more than two positions. For example and in one embodiment of the invention, between about six and a half and twenty-four pounds of material would be spread per minute when using a six foot hose. The exact flow rate of particulate materials can also vary depending on the diameter of the entrance and exit conduits  24  and  26 , the size and geometry of the metering chamber  22 , and the density of the material being spread. 
     In another embodiment of the invention, the spreader  20  can be altered so that more than one person can use it at one time. As shown in FIG. 5 a,  the compressor  38  can be used to supply compressed gas to two metering blocks  22   a,b.  In one embodiment of the invention, each air line  40  is connected to its own air tank  36 , although it is also possible to have one air tank  36  supply air for two air entrance conduits  24  as shown in FIG. 5 b.  Where there two air tanks  36   a  and  36   b,  a pressurized gas entrance conduit  24   a,b  connects each air tank  36   a,b  to separate metering blocks  22   a,b,  with material hoppers  28   a,b  located above respective metering blocks  22   a,b . Each metering block  22   a,b  has an exit conduit  26   a,b  leading away from it towards a respective wand  58   a,b . In this manner, two users may use separate wands  58   a,b  so as to be able to spread the material in different directions. In a preferred embodiment of the invention, a compressor which produces more cubic feet of gaseous material per minute would be used. 
     In a second alternative embodiment of the invention as shown in FIG. 6, a second material hopper  100  can be placed inside the primary material hopper  28 . The second material hopper  28  is connected to the primary hopper  28  by a hook  108  or other mechanical means that are well-known to those skilled in the art such as bolts or latches. The second hopper  100  is coupled to a flexible line  102  which runs to the bottom of the primary hopper  28 . An additional ball valve  104  is coupled to the line  102  for adjusting, the flow of material from the second hopper  100 . Attached to the base of the primary hopper  28  and the line  102  is a fitting  106  which allows material from both hoppers  28  and  100  to enter the passage  30  leading to the metering block  22 . Depending upon the particular system requirements, the material can flow from both hoppers  28  and  100  simultaneously, or the ball valve  104  could be of the type that permits material to flow from only one of the hoppers  28  and  100  at a time. Due to the smaller dimensions of the second hopper  100  and the line  102 , it is preferable that very light materials such as seed or insecticide be used in the second hopper  100 , although other materials may be possible. 
     In yet another embodiment of the invention as shown in FIG. 1, the spreader  20  includes all of its essential components arranged inside a frame  90  that is of proper size so as to be able to be placed in the back of a vehicle  80  such as a low-bed pickup. Several such “Truckster” vehicles, such as a John Deere Gator, a Toro Utility Vehicle, a Cushman Utility Vehicle, a Kawasaki Mule, or a Haulmaster are all capable of having the frame  90  of the particulate spreader stored thereon. By having the hose  48  be of a sufficient length, the user is capable of directing the wand  58  to spread particulate material while still keeping the vehicle  80  in motion. Additionally, it is also possible to have the particulate spreader  20  mounted on a trailer to be towed by a motorized vehicle. The user(s) may apply particulate material while seated in or even while driving the vehicle, or the user may stand near the vehicle while spraying the material. 
     Another embodiment of the invention is shown in FIG. 7, in which an alternative metering assembly, shown generally at  200 , is used to meter precise quantities of material for spreading. The metering assembly  200  comprises a first section  202 , a second section  204  and a third section  206 . The first section  202  and the third section  206  are maintained in a substantially constant position relative to the passage  30 . The second section  204 , however, is movable between first and second positions. In one embodiment of the invention, an actuator  212  is coupled to the second section  204  by an actuator arm  214 . The second section  204  includes a first storage area  208  and a second storage area  210 . 
     When the second section  204  is moved into a first position, shown in FIG. 7, the second storage area  210  is located directly beneath the passage  30 . This positioning permits the second storage area  210  to fill with a specific amount of material to be spread. At the same time, if the first storage area  208  had previously been filled with material, then the material in the first storage area  208  falls through a first storage conduit  218  to be entrained by the stream of air emanating from the nozzle  54 , forcing the material into the exit conduit  26 . After the second storage area  210  is filled with material, the actuator  212  moves the second section to a second position (not shown), in which the material from the second storage area is entrained by the stream of air from the nozzle after the material passes through a second storage conduit  220 . At the same time, the first storage area  208  is positioned beneath the passage  30  so that the first storage area  208  may be filled with material. 
     In the embodiment shown in FIG. 7, the nozzle  54  is positioned within a nozzle chamber  222  such that the nozzle  54  extends a length w between about five-eighths to about three-quarters of the distance d from one end of the nozzle chamber to the point at which the first storage conduit  218  begins. 
     The arrangement described in FIG. 7 permits the user to meter a specific, controlled amount of material for application, ranging from about one quarter of a teaspoon to much larger quantities. In one preferred embodiment of the invention, the second section  204  is replaceable such that exact quantity of material to be metered can change depending upon the user&#39;s particular requirements. 
     While several preferred embodiments have been shown and described, it is understood that changes and modifications can be made to the invention without departing from the invention&#39;s broader aspects. For example, instead of using two material hoppers for an apparatus that comprises two hoses for spreading the particulate materials, the apparatus could use one large hopper which is connected to both metering blocks. Also, the metering block can have the shape of a cylinder, wherein the first and second walls mentioned in the specification would each represent a portion of the inner cylindrical wall of the block. Additionally, it is possible to use fluids other than pressurized air to transport the particulate materials through the exit conduit. Instead of relying on a dedicated engine, the prime mover of the pump could be a vehicle engine with power obtained from a belt, shaft, or hydraulic line, and a different power/pressurized air regulation scheme. Finally, it is feasible that frozen materials such as very fine-grained snow or ice could be spread using this apparatus. Thus, it is apparent that alternative embodiments are available to those skilled in the relevant art. Therefore, the present invention is not limited to the described and illustrated embodiments but only by the scope and spirit of the appended claims.