Abstract:
A portable, towable livestock sprayer establishes a portal through which livestock move. A rigid, frame includes a removable tongue for connection to the draft vehicle. A pivoted, wheeled subframe hinged to the frame is switched between deployed or retracted orientations. The tongue fits to the subframe and functions as a leverage tool. With the sprayer properly positioned adjacent a livestock gate, a shroud assembly is deployed. Photo-eyes determine the presence and direction of travel of animals being sprayed. A pump system controls solution. The shroud transforms between a stable, compact transportation orientation, and a deployed orientation conformed to the required dimensions. Separate, extensible shroud wings are folded together during transportation, or separately deployed on opposite sides of the sprayer to block escape routes. Each wing comprises an inner section adapted to be removably coupled to the frame, and an outer section slidably telescoped to the inner section enabling width adjustments.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     I. Field of the Invention  
         [0002]     The present invention relates generally to cattle sprayers for applying pesticides. More particularly, my invention relates to a walk-through cattle sprayer that automatically senses the presence and direction of roving livestock, and applies a uniform spray in response.  
         [0003]     II. Description of the Prior Art  
         [0004]     It is well recognized by farmers and ranchers that livestock must be periodically sprayed to combat parasites and reduce infection. For horse and livestock, ectoparasite infestation is a well-known affliction. Stable flies or horn flies are aggravating and troublesome, especially in the hot summer months. Fleas, ticks and mosquitoes are bothersome as well. Various species of flies and airborne pests can penetrate the hair of livestock and lay eggs in the skin or beneath the surface of the skin. The West-Nile virus, transmitted by mosquitoes, is another danger. Cattle can be especially vulnerable in the hot summer months. Numerous diseases are spread in this fashion. In dairy operations, fly infestation can also decrease milk production. Consequently, a variety of insecticides or treatments are known in the art. These may be applied by hand-spraying the animals, or automated spray devices may be employed to spray the animals upon detection. Animals may also be dipped, but the latter approach is cumbersome and inefficient.  
         [0005]     Hand-operated sprayers are slow and cumbersome. Some portable models must be reloaded often, and they generally do not apply a uniform spray. Moreover, the repeated spraying of large herds is a difficult and labor intensive, time-consuming requirement. Accordingly, automated systems have been developed in the art. Typically, groups of animals are diverted to spraying areas in which fixed equipment is deployed. U.S. Pat. No. 2,499,174, issued Feb. 28, 1950, discloses a spraying apparatus for livestock. The device is in the nature of a shower, whereby fluid may be dispersed under and over the cattle in order that they will be thoroughly coated with the fluid and, of course, the fluid may be impregnated with any of the well-known insecticides. An over-head shower is suspended above the animals.  
         [0006]     U.S. Pat. No. 2,524,641, issued Oct. 3, 1950, discloses a portable sprayer for the treatment of livestock. The device is transported by a tow vehicle.  
         [0007]     U.S. Pat. No. 2,542,280, issued Feb. 20, 1951, discloses an automatic spray chute for spraying cattle or other animals. The sprayer covers the animal entirely with the sprayed material, which is preferably directed “against the grain” of the animal&#39;s hair or fur.  
         [0008]     U.S. Pat. No. 2,595,781, issued May 6, 1952, discloses another portable livestock or cattle spraying chute. Spray nozzles direct treatment solution against animals confined within the chute. The chute is mounted upon a wheeled carriage used for transporting the apparatus.  
         [0009]     U.S. Pat. No. 2,684,658, issued Jul. 27, 1954, discloses a portable sprayer comprising an animal passageway through which the livestock to be sprayed pass. A plurality of spray nozzles disposed along the inner surfaces of the passageway direct fluid onto the animals.  
         [0010]     U.S. Pat. No. 2,702,020, issued Feb. 15, 1955, describes a liquid applicator for applying disinfectants or liquid medical compounds to hogs, calves, and other animals. The invention consists of a cylindrical container from which absorbent flaps extend. These flaps directly contact animals walking under the applicator.  
         [0011]     U.S. Pat. No. 3,071,111, issued Jan. 1, 1963, discloses a liquid applicator for dispensing liquid from a storage reservoir without pumps or valves. The dispensing is accomplished by gravity feed, but is constructed so that flow from the container is effectively checked and controlled during activation of the unit. By displacement of the apparatus through contact made by the animal, the flow of liquid is effectively controlled in order to prevent continuous and wasteful dispensing during such activation.  
         [0012]     U.S. Pat. No. 3,108,574, issued Oct. 29, 1963, describes a cow washing and jet spray device and a controlling valve mechanism that is actuated by physical movement of the animal. The control mechanism opens the valve substantially and immediately upon initial physical impact.  
         [0013]     U.S. Pat. No. 3,116,717, issued Jan. 7, 1964, describes a cattle insecticide applicator that includes flexible members saturated with insecticide or oil for directly wiping the animal. The apparatus is preferably deployed in a livestock pathway to be activated by passing animals.  
         [0014]     U.S. Pat. No. 3,285,231, issued Nov. 15, 1966, utilizes a brush-like structure to physically wipe the back of animals passing through a confined passageway. Liquid insecticide is released when a valve is opened by the movement of the animals, and when the animal departs, the valve shuts off the system.  
         [0015]     U.S. Pat. No. 3,541,996, issued Nov. 24, 1970, discloses an automatic sprayer that dispenses predetermined volumes of treating fluids when animals traverse a U-shaped housing surrounding the periphery of an entranceway. An elongated actuator arm is physically triggered by physical contact with animals.  
         [0016]     U.S. Pat. No. 3,602,199, issued Aug. 31, 1971, discloses an automatic livestock sprayer activated by animal passage. Pressure cylinders provide regulated pressure and a constant spray rate.  
         [0017]     U.S. Pat. No. 3,763,828, issued Oct. 9, 1973, shows a sprayer for applying liquid to a cow&#39;s udder. The device is triggered by animals moving through a narrow passageway. A photoelectric cell is positioned so that the light beam is broken when the cow&#39;s udder is above a spray nozzle.  
         [0018]     U.S. Pat. No. 4,379,440, issued Apr. 12, 1983, discloses a portable livestock spraying apparatus which includes a confining chute and numerous spray nozzles. Similar patents include U.S. Pat. Nos. 4,669,425, 4,748,939, 4,978,861, 5,063,880, and 6,095,430.  
         [0019]     However, so-called portable sprayers are often cumbersome and difficult to transport and deploy. Spraying operations are best served a reasonable distance away from feed stocks or watering holes, and often easily-accessible power outlets or water faucets are unavailable. When such units are extremely heavy, it may take more than a single workman to operate and deploy the apparatus. On the other hand, where the apparatus is too light and/or unstable, inadvertent contact with animals can dislodge or tip it over.  
       BRIEF SUMMARY OF THE INVENTION  
       [0020]     My new cattle sprayer is deployed on a wheeled frame that can be quickly towed to an applicator site. This invention provides a portable, lightweight spray unit with a self contained electrical system and its own spray reservoir. It may be freely and quickly installed at varying locations about a ranch or farm by a single operator. Adjustable gates enable width compensation, so the unit can completely block and seal a gate or passage through which animals pass.  
         [0021]     A removable tongue is releasably connected to the front of the frame for connection to a suitable draft vehicle. The frame comprises a hinged subframe equipped with a pair of wheels that pivots between positions. The subframe is deployed with the aid of the tongue, which is configured as a manipulative tool for use in deploying the subframe. The tongue removably attaches to a socket on the subframe. When so connected, the tongue may leverage the subframe to tilt it into a transportation orientation. The subframe includes means for pinning it into proper position relative to the main frame. With the sprayer properly positioned adjacent a livestock gate or trail, a shroud assembly is deployed to block any escape routes the livestock might otherwise have around the sprayer.  
         [0022]     The frame supports an upright pair of stanchions defining a portal through which the livestock pass. Suitable photo-eye apparatus determine not only the presence of an animal needing spraying, but the direction of travel and the total count of sprayed animals. By controlling the direction of travel, spray efficiency is maintained. For example, when a meadow has a pool or lake, cattle moving in this area will be sprayed only if they are moving away from the water, rather than towards it.  
         [0023]     A pump and recirculation system controls the solution to be sprayed. When an animal is detected moving in the right direction, solution is vigorously sprayed upon cattle traversing the passageway. Nozzles are provided on both sides and on the top of the framework.  
         [0024]     Importantly, the shroud can quickly be transformed between a stable, compact transportation orientation, and a deployed orientation conformed to the space requirements demanded. The assembly comprises a pair of separate, extensible wings that can either be folded adjacent one another, or separately deployed on opposite stanchions to extend away from the sprayer to block any space that animals might use to bypass the sprayer. Each wing comprises an inner section adapted to be removably coupled to the frames&#39; vertical stanchions, and an outer section that is slidably telescoped to the inner wing section. As the twin wing sections are telescoped relative to one another, varying lengths are produced to customize the sprayer for paths and gates of different dimensions.  
         [0025]     Measured amounts of fluid are dispensed by a control system that ensures proper application. Moreover, the presence and direction of animals traversing the apparatus is sensed and determined. Application occurs only when the animals are moving in the proper direction. For example, this “one way” feature insures that animals will be sprayed when leaving a pond or lake, rather than when they are on their way to bathe.  
         [0026]     Thus, a fundamental object of my invention is to provide a portable sprayer device for automatically detecting livestock and applying a measured, uniform spray to combat insects and parasites.  
         [0027]     Another basic object is to kill flies and other insects and pests.  
         [0028]     Another fundamental object it to treat insect infestation in livestock.  
         [0029]     Yet another object of the present invention to provide an automatic spraying device that checks to see that a desired direction of animal movement is attained.  
         [0030]     A still further object is to provide a portable, automatic sprayer that can be user-adjusted to a dimension which effectively surmounts a desired passageway or entranceway through which animals pass.  
         [0031]     A related object is to provide an automatic animal sprayer that electronically detects both the presence and direction of travel of an animal to be treated.  
         [0032]     These and other objects and advantages of the present invention, along with features of novelty appurtenant thereto, will appear or become apparent in the course of the following descriptive sections.  
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0033]     In the following drawings, which form a part of the specification and which are to be construed in conjunction therewith, and in which like reference numerals have been employed throughout wherever possible to indicate like parts in the various views:  
         [0034]      FIG. 1  is a frontal isometric view of my new sprayer, shown deployed for transportation, with portions thereof omitted for brevity or sectioned for clarity;  
         [0035]      FIG. 2  is a rear isometric view thereof;  
         [0036]      FIG. 3  is a side elevational view thereof;  
         [0037]      FIG. 4  is a top plan view thereof;  
         [0038]      FIG. 5  is a front plan view thereof;  
         [0039]      FIG. 6  is a rear plan view thereof;  
         [0040]      FIG. 7  is an enlarged, fragmentary front elevational view of the gate structure, with the shroud assembly shown partially deflected vertically and upwardly, as it appears just prior to deployment and unfolding;  
         [0041]      FIG. 8  is a partially exploded, isometric view showing the gates extended and detached, the draw tongue removed, and the transportation axle rotated to a rest position;  
         [0042]      FIG. 9  is an isometric view similar to  FIG. 8 , but showing the gates deployed, the draw tongue removed, and the transportation axle disposed in a rest position;  
         [0043]      FIG. 10  is a partially exploded front elevational view similar to  FIG. 8 , but showing the draw tongue deployed in a position for leveraging and deploying the transportation axle;  
         [0044]      FIG. 11  is a partially fragmented, front elevational view of the operating unit;  
         [0045]      FIG. 12  is a diagrammatic view illustrating the fluid control circuit;  
         [0046]      FIG. 13  is a schematic flow diagram showing the software logic implemented by the controller;  
         [0047]      FIG. 14  is an enlarged fragmentary isometric view of circled portion  14  in  FIG. 1 ; and,  
         [0048]      FIG. 15  is an enlarged fragmentary isometric view of circled portion  15  in  FIG. 1 .  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0049]     Turning now to the drawings, my new portable sprayer has been generally designated by the reference numeral  20 . It is adapted for automatic use with a variety of livestock, including horses, cattle, sheep and the like. Sprayer  20  comprises a rigid frame  22  ( FIG. 2 ) that is adapted to be disposed upon the ground  24  or other relatively flat supporting surface. Rigid, upright portal  26  that is vertically supported upon frame  22  defines a passageway  27  through which livestock moves to be sprayed. The sprayer is towed by attachment to a removable tongue  29  normally projecting from the front of the frame  22 . The frame forms a towable carriage with subframe  32  that is pivotally coupled to the frame at the rear of the sprayer  20 .  
         [0050]     To tow the sprayer  20 , the pivotal subframe  32  at the rear of the sprayer  20  is deployed as seen in  FIG. 1 , with wheels  33  ( FIG. 2 ) fully contacting and rolling upon ground  24 . When a desired spray location is reached, the subframe  32  is uncoupled and it pivots to the “out of the way,” retracted position seen in  FIGS. 8 and 9 . When the sprayer  20  is properly positioned adjacent a livestock gate for spraying moving livestock, the shroud assembly  34  is unpacked and extended from the sides of the sprayer to block any escape pathways, insuring that the animals are all treated. However, the shroud assembly  34  is temporarily stored within the passageway area  27  and secured relative to the frame during transportation of the sprayer  20  between locations. When the sprayer reaches the desired operational destination, the shroud assembly  34  is then unconnected and deployed, as will hereinafter be described in detail.  
         [0051]     The battery-powered control circuitry to be described hereinafter is located within housing  36  atop portal  26  for activating the sprayer  20 . Photo eyes  40  detect the presence of cattle or livestock. Each photo eye unit contains a pair of photocell units aimed at a mirror on the opposite side of the portal. When an animal breaks the light return path, the presence of an animal is detected. However, as there are pair of units, the direction of animal travel is determined as well. The treatment solution to be sprayed (i.e., insecticide, pesticide or the like) is stored within tank  38  over portal  26 . Upon appropriate detection, solution is vigorously sprayed upon cattle traversing the passageway  27 , through nozzles  42 , as explained in detail hereinafter. Solar collector panel  41  recharges the batteries (not seen) within housing  36 .  
         [0052]     With primary reference directed to  FIGS. 1-2 ,  4  and  8 - 10 , the welded, tube steel frame  22  ( FIGS. 2, 9 ) is generally rectangular, comprising a front span  44 , a rear span  45  ( FIGS. 1, 9 ), and a pair of spaced apart and parallel sides  47  extending between front and rear spans  44 ,  45 . The smaller, steel subframe  32  is also rectangular. The subframe legs  49  extending from opposite sides of subframe end  52  are pivotally coupled to frame sides  47  via hinges  51 . When the subframe  32  is deployed for sprayer transportation and movement as in  FIG. 2 , it is parallel with the main frame  22 . To this effect there is a middle subframe leg  53  disposed between the outermost subframe legs  49 . Legs  49  and  53  are parallel. The rear span  45  of the main frame  22  has a short stub  54  projecting from it. When the subframe  32  is oriented parallel with the frame  22  during sprayer movements (i.e., as in  FIGS. 1-3 ), the middle subframe leg  53  assumes a position parallel to and adjacent with stub  54 , and is held by fasteners  56  (i.e.,  FIGS. 2, 4 ) are inserted between and through the aligned stub  54  and subframe middle leg  53  to pin and thus lock the subframe  32  relative to the frame  22 .  
         [0053]     The towing tongue  29  is removable from the sprayer, and it has multiple functions. The conventional trailer socket  58  is secured on a conventional neck  59  ( FIG. 2 ) that is connected to tongue shaft  60  ( FIGS. 2, 8 ). A lower, angled terminal portion of the shaft  60  is slidably and releasably captivated within the angled anchor sleeve  62  (i.e.,  FIGS. 1-3 ,  8 ) welded to front frame span  44 . When tongue  29  is coupled to sleeve  62  in this fashion and then pinned (and the subframe  32  is similarly secured within frame  22  as aforesaid), the entire sprayer may be conveniently towed about by a suitable tractor or “all terrain vehicle” (i.e., an “ATV”) which is coupled to the tongue in the usual manner. Given the weight and construction of the sprayer  20  as discussed, an ATV like a Honda Model  400  four wheel drive unit is more than adequate.  
         [0054]     However, the tongue  29  has an important alternative function. After the sprayer  20  is towed to a suitable location, the tongue  29  can be removed from sleeve  62  (i.e.,  FIGS. 1, 3 ) for use as a lever to manipulate the subframe, as seen in  FIG. 10 . It will be noted that the subframe  32  supports an alternative square socket  64  (i.e.,  FIGS. 1 ). When the tongue  29  is inverted and then inserted into subframe socket  64 , the subframe can be manipulated to deflect and align the previously described subframe leg  53  and stub  54 . This enables the fasteners  56  to be inserted or withdrawn. When the sprayer is transformed into the operational position of  FIGS. 8, 9 , the subframe  32  pivots upwardly about hinges  51  when the fasteners  56  are removed, and subframe is forced by gravity away from its former parallel orientation with respect to the flat and stationary frame  22 . When the subframe is to be moved back into the transportation position (i.e., from the position of  FIG. 8  to that of  FIG. 2 ), tongue  29  is positioned as in  FIG. 10 . The tongue engages socket  64  ( FIGS. 2, 4 ) and shaft portion  60  functions as a lever for manually manipulating and facing the subframe  32  back into position with wheels  33  contacting the ground and elevating the sprayer. Hand manipulation occurs just prior to reinstalling the wing-nut fasteners  56  to pin the subframe into the transportation position.  
         [0055]     The upright portal  26  surrounds the passageway  27  through which livestock to be treated pass. Two parallel, vertically upright stanchions,  68 ,  69 , respectively, are welded to frame spans  45  and  44 . A rigid upper strut  70  ( FIG. 1 ) transversely extends between stanchions  68  and  69 , forming the top of portal  26 . Strut  70  supports tank  38 , control housing  36 , and the solar collector panel  41  on its top, as well as the spray nozzle  42  which is mounted on its underside facing downwardly towards passageway  27 . Other spray nozzles  42  are also secured to stanchions  68  and  69 , and they face inwardly towards the passageway  27 . Livestock  67  ( FIG. 11 ) detected within the passageway are treated with vigorous spray patterns  61  ( FIG. 11 ) established by the cooperating nozzles  42 . To prevent dripping, leakage, or siphoning through the nozzles when the sprayer (i.e., the pump) is turned “off”, each spray nozzle  42  includes an internal check valve nominally rated at twenty pounds. Fluid can only be sprayed through the nozzles  42  in response to predetermined line pressure.  
         [0056]     A pair of spaced-apart photo eyes  40  is mounted within housing  39  on stanchion  68  ( FIG. 1, 14 ). The photo eyes  40  direct a beam of light across the portal and passageway  27  towards a companion pair of reflectors  43  ( FIGS. 2, 15 ) mounted in a similar housing  39 B ( FIG. 15 ) on stanchion  69 . Preferably three-inch diameter, center-mounted Allen Bradley model  92 - 39  reflectors are used.  
         [0057]     By using a pair of photo eyes and a pair of companion reflectors, the direction of travel, rather than the mere presence of an animal, is ascertained. Each Allen Bradley brand photo eye  40  comprises a light emitter and a companion sensor. Light directed across the portal towards the reflectors  43  is normally reflected back and sensed, in the absence on an animal, whose presence breaks the return path of reflected light. Depending upon which of the two sensors first detects “breaking” of the normal beam pattern, not only the presence of an animal is detected, but the direction of animal travel is determined as well. As explained hereinafter, the control system will not initiate a spray sequence unless the direction of travel is correct.  
         [0058]     The shroud assembly  34  comprises a pair of separate, extensible wings  72  (i.e.,  FIG. 8 ). With primary reference directed now to  FIGS. 7-9  and  11 , each wing  72  is identical. The purpose of the wings  72  is to shroud that portion of an animal path that is between the sprayer  20  and adjacent structure, such as posts  74  ( FIG. 11 ). Each wing  72  comprises an inner section  76  adapted to be coupled to one of the vertical stanchions  68  or  69 , and an outer, extensible section  77  that is slidably telescoped to section  76 . Preferably, each inner wing section  76  comprises three spaced-apart and parallel rails  78 ,  79 ,  80  extending horizontally between vertical ends  81 ,  82  (i.e.,  FIG. 7 ). Rails  78  and  80  terminate inwardly in L-hooks  84 ,  85  respectively ( FIG. 7 ) that project downwardly towards sleeves  88 ,  89 . Pairs of sleeves  88 ,  89  are welded in spaced relation upon both stanchions  69  and  68 . Outer wing sections  77  preferably comprise three spaced apart and parallel horizontal rails  83  welded to an end piece  87 . Rails  83  are slidably, coaxially telescoped to rails  78 ,  79 ,  80  of the inner wing sections  76 .  
         [0059]     When inner and outer wing sections are telescoped together for transportation (i.e., as in  FIG. 1 ), abutting wings are held folded together in flat, abutting relation place by projecting clasps  90  (i.e.,  FIGS. 8, 9 ). In the transportation mode of  FIGS. 1 and 7 , the twin wings  72  are folded adjacent one another and positioned substantially as in  FIG. 7 , such that the hooks  84 ,  85  mate within and are captivated by the sleeves  88 ,  89 . When deployed outwardly for spraying operations, the wings  72  are oriented and manipulated as illustrated in  FIGS. 8, 9 , such that they project laterally away from the stanchions  68 ,  68 , with L-hooks  84 ,  85  appropriately aligned with and mated to sleeves  88 ,  89 , and with the formerly telescoped sections pulled apart to shroud the areas adjacent the sprayer.  
         [0060]     The fluid control and flow circuit has been generally designated by the reference numeral  100  ( FIG. 12 ). Where practicable, reference numerals used previously to indicate hardware items are used again to designate the same parts in schematic form. Reservoir tank  38  stores a volume of insecticide to be applied as aforesaid.  
         [0061]     To load tank  38 , solution may be suctioned from a user-supplied, external container  102  via a line  103  through manually operated first control valve means comprising valves  104  and  109 . Valve  104  connects to the twelve-volt D.C. pump  105  via a conventional T-connection. Electric pump  105  fills tank  38  through manual valve  106  that outputs via lines  108 ,  110  into tank inlet  112 . At this time manual valves  109  and  111  remain closed. After filling tank  38 , manual valves  104  and  106  are closed, and the second control valve means (i.e., comprising valves  109  and  111  is opened.  
         [0062]     With valves  109  and  111  open, solution may be sprayed. Fluid is drawn from tank  38  via strainer/check-valve  101  through line  107  and valve  109  into pump  105 , which outputs through opened valve  111  and lines  113 ,  114 ,  115 ,  116  and  118  to spray nozzles  42 . A return bleed-off line  121  communicates with check-valve equipped tank nozzle  123  to vent overpressure, recycling fluid to tank  38 . Spraying occurs when the pump  105  is actuated by the controller to be described hereinafter, after tank  38  is filled, and valves  109  and  111  are opened.  
         [0063]     The controller circuitry implements the logic of  FIG. 13  through a programmable Allen Bradley model 1760-L-12DWD controller disposed within housing  36 . The software control program has been generally designated by the reference numeral  120  ( FIG. 13 ). Program initiation is manually switched “on” as indicated by step  122 , thereby energizing node  123 . A “test mode” switch is turned on in step  124  to bypass the sensing circuitry; this is done when filling the tank  38  or testing it. If the test mode switch  124  is “on,” the pump  105  (i.e.  FIG. 12 ) is energized per step  125 . In step  126  a first, conventional level-measuring float within solution tank  38  (i.e.,  FIG. 1 ) is queried; if the tank is empty, a warning light is flashed in step  128 , warning of an empty tank. If the tank is empty, the controller does not actuate the pump. A separate float within the tank can sense a “low tank” condition in step  129 , it is indicated by warning lights flashed in step  130 . When solution is “low,” the tank  38  should be filled as discussed above.  
         [0064]     Step  122  also initiates an animal counting function if the test mode switch in step  124  is “off.” Photo eyes  40  are queried in step  134  to determine animal presence, and the right direction of travel. Of the two sensor paths in the assemblies, the first signal must be derived from the appropriate sensor to determine if the travel direction is right. If the travel direction is right, the count is made in step  135 . The operator must input a manual decision by activating a “count only” switch in step  137 ; if “true” (i.e., animals are counted but not sprayed), a return occurs on line  138 . If “false” (i.e., spraying should commence), then step  139  implements a delay timer so that spray does not get in the face of the animals. Delay completion is sensed at  140 ; if an appropriate selected time interval has elapsed, step  142  turns on the sprayer and starts a spray counter. Step  142  thus energizes pump  105  after valves  109 ,  111  ( FIG. 12 ) are first manually opened.  
         [0065]     Step  144  monitors the photo eye assemblies  40  to make sure an animal is still present (i.e., that the optical path across the portal is still blocked.) Timing step  146  monitors the length of time that spray is applied. If the sprayer is on too long (i.e., pump  105  is running) or if the animal being sprayed exits the portal, then a turn-off step  148  occurs. This causes a timer reset in step  150 , returned on line  151 , and the circuit  120  looks for a new animal, whereupon the process is repeated.  
         [0066]     From the foregoing, it will be seen that this invention is one well adapted to obtain all the ends and objects herein set forth, together with other advantages which are inherent to the structure.  
         [0067]     It will be understood that certain features and sub-combinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.  
         [0068]     As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.