Abstract:
A walk from behind, also called a push or cart sprayer having an assembly of wheeled frame and a tank. The frame has a rearward extending handle which enables the assembly to be pushed along a path. The tank has a connected boom assembly including a pivotal boom arm along the front of the tank with a distal spray nozzle, and a mechanism enabling the boom arm to be pivoted to the sides of the tank where the nozzle sprays away from the path, to the side of the path, so that possible toxic or corrosive spraying liquid cannot be stepped upon by the operator pushing the sprayer, thereby enhancing safety of operation. The boom arm is also pivotal to the front of the tank, such as useful when the cart sprayer is towed.

Description:
[0001]    Priority is claimed to U.S. Provisional Patent Application Ser. No. 62/329,817, filed Apr. 29, 2016, which is herein incorporated by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to cart sprayers, and particularly to push from behind cart sprayers, sometimes called push, cart sprayers. The cart sprayer of the present invention is especially useful to control the location of sprayed liquid along the ground with respect to the path of travel of the sprayer using a multi-positional movable boom disposed along the front of the sprayer. 
       BACKGROUND OF THE INVENTION 
       [0003]    Cart sprayers often spray corrosive and/or toxic liquids which can present a safety hazard. This hazard confronts operators of cart sprayers on the market, as for example from Master Manufacturing of Paynesville, Minn., Fimco Industries of North Sioux City, S. Dak., TurfEx Products of Madison Heights, Mich. and Earthway Products Inc. of Bristol, Ind. Such cart sprayers have fixed nozzles mounted on the carts thereof, especially to their tanks and at the front of the tanks. Therefore spray is dispensed ahead of the sprayer over the ground where the sprayer travels and through which the operator must walk while pushing the sprayer from behind. 
       SUMMARY OF THE INVENTION 
       [0004]    Accordingly, it is a principal object of the invention to provide an improved cart sprayer which can be pushed from behind without endangering the safety of the operator by requiring the operator to push the sprayer and walk on freshly sprayed areas of the ground just sprayed upon. 
         [0005]    It is an object of the invention to provide an improved cart sprayer having a boom arm rotationally mounted along the front of the sprayer to extend away from the sprayer, which can be selectably rotated to the left of right side of the path of travel of the cart sprayer to apply pumped liquid via a nozzle disposed at the distal end of the boom arm along the left or right side, respectively, of such path of travel. 
         [0006]    Another object of the invention is to provide an integrated assembly of tank, frame and electrical and hydraulic components in an improved cart sprayer. 
         [0007]    It is another object of the invention to provide an improved cart sprayer having a frame with a saddle supporting the tank of the sprayer in the center of the tank, and with wheels on the frame, and also with a push from behind handle on a shaft carried by the frame. 
         [0008]    The present invention provides an improved cart sprayer where the ground spraying nozzle is moveable to a position away from the path over which the sprayer travels to a selected position out of that path. This position is next to said path, preferably to a side thereof. A boom assembly is provided for moving the nozzle to the selected position having an arm which carries the nozzle near or at the outward distant end of the arm. The arm is rotatably mounted in a mounting of the boom assembly attached to the cart sprayer, preferably at the front of the tank thereof, and hence may be referred to herein as a boom arm. The arm is rotated by the operator to bring the nozzle to its selected position. A mechanism in the boom assembly releasably locks the boom arm at the selected position. The selected position of the boom arm may be one of two positions on opposite sides of the spray cart, each  180 ° of the rotation of the arm, apart from each other. Accordingly, neither the cart sprayer, nor the operator walking behind the sprayer, travels upon freshly sprayed ground just sprayed upon, thereby avoiding being exposed to the danger of toxic or corrosive spraying liquid. Optionally, the cart sprayer may be towed, and the selected position of the boom arm moved to the front of the sprayer cart  90 ° of rotation of the arm from selected side positions. 
         [0009]    To rotationally mount the boom arm, the cart sprayer has a bracket having a slot mounted along the front of sprayer&#39;s tank, a pin (or pivot member) extends through a central hole of the bracket via the slot, and the boom arm has a proximal end with an opening through which such pin extends to rotationally mount the boom arm for motion about such pin along the slot of the bracket. The pin defines the axis of rotation for the boom arm along the slot of the bracket to move the nozzle disposed at the distal end of the boom arm about an approximate 180° rotation around the front of the tank. 
         [0010]    To minimize risk of damage to the boom arm during storage or transportation of the cart sprayer, another opening is provided at least approximately centered about a length of the boom arm, and the pin is repositioned to extend through the bracket&#39;s central hole and this another opening of the boom arm via the slot of the bracket, so as to minimize rotational motion of the arm and to reduce the extent the boom arm extends distally from the sprayer. 
         [0011]    The mechanism for releasably locking the boom arm may have detents along one of the walls defining the slot of the bracket for engaging a spring biased member of the boom arm when the boom arm is pivoted to each of its pivot positions. Preferably, such mechanism for releasably locking the boom arm is provided by a plurality of holes in the bracket that extend into the slot of the bracket, where each hole is associated with a different one of the boom arm&#39;s pivot positions, and a retainer member, such as a pin, being received in one of such plurality of holes to engage the boom arm so as to lock the boom arm from pivoting. Removal of the retainer member enables selection of another hole in the bracket associated with a different one of the pivot positions to receive the retainer member for engagement with the boom arm. 
         [0012]    The invention also provides a cart sprayer having an integrated assembly of a frame and a tank. The frame may have a U-shaped saddle section which fits into a recess between upper and lower sections of the tank. Downwardly extending legs of the saddle section hold bearings for a shaft, and at the ends of the shaft wheels of the cart are rotationally mounted. These legs are attached to the tank on a flat back side thereof opposite a front side which is curved, and such front side has the recess for containing the U-shaped part of the saddle section. A back section of the frame has side legs which are attached to the legs of the saddle section of the frame. The downward ends of these side legs can provide feet for resting the cart sprayer on the ground. The upper part of the side legs merge together into an upwardly tilted position along a shaft which is attached to handles for pushing the cart sprayer from behind. 
         [0013]    The cart sprayer has an electro-hydraulic system with the components thereof mounted on the inside and on the outside of a plate. This plate is attached to the back of the tank over a recess or space in the tank wall for containing the components which are mounted on the inside of the plate. The outside of the tank has a receptacle for a removable and replaceable battery (preferably of the rechargeable lithium-ion type). The battery powers an electric motor driven demand pump mounted on the inside of the plate. Also mounted on the inside of the plate is an electrical switch responsive to the output pressure of the pump for cutting off power from the battery to the pump drive motor when the pressure exceeds a certain pressure (for example, 50 psi). 
         [0014]    A spray wand with a shut-off may be connected to the pump output via a two-way valve mounted on the inside of the plate with a control handle or lever on the outside of the plate. The spray wand has a trigger controlling such shut-off so that the operator can enable or disable flow of pumped liquid to the spray head which is mounted at the end of the wand&#39;s tubular shaft. The liquid from the tank may be pumped by the pump via the two-way valve to select either spraying with the wand, or the nozzle on the boom arm. 
         [0015]    When the wand is selected by the control handle of the two-way valve and spraying is stopped by the shut-off on the wand, the increase in output pressure from the pump is sensed by the pressure responsive switch and electric current to the pump motor is disconnected, all automatically. This integrated electrical hydraulic and mechanical assembly of spray liquid tank, a wheeled frame, and electrical and hydraulic components on the inside and outside of a mounting plate, provides an improved multi-function (boom nozzle and wand) cart sprayer system. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    The foregoing and other objects and advantages of the invention will become more apparent from a reading of the following detailed description with the accompanying drawings wherein: 
           [0017]      FIG. 1  is a side view of a cart sprayer embodying the invention, the view being taken from the right side of the sprayer; 
           [0018]      FIG. 2  is a top view of the cart sprayer of  FIG. 1  with a boom arm carrying a ground spraying nozzle positioned along the path of travel of the sprayer, especially for tow-from-behind operation with the ground spraying nozzle; 
           [0019]      FIG. 3  is a top view similar to  FIG. 2 , but with the boom arm pivoted to another position bringing the ground spraying nozzle to a right side of the path of travel of the sprayer; 
           [0020]      FIG. 4  is a top view similar to  FIGS. 2 and 3 , but with the boom arm in another position than shown in  FIGS. 2 and 3 , namely to bring the ground spraying nozzle of the boom arm to a left side of the travel path of the sprayer; 
           [0021]      FIG. 4A  is a perspective view of the cart sprayer of  FIG. 1  taken from the front thereof in which the boom arm is positioned as shown in  FIG. 4 ; 
           [0022]      FIG. 4B  is a side view of the cart sprayer of  FIG. 1  taken from the right side thereof in which the boom arm is positioned as shown in  FIG. 4 ; 
           [0023]      FIG. 5  is a front view of the cart sprayer of  FIG. 1 ; 
           [0024]      FIG. 5A  is another front view of the cart sprayer of  FIG. 1  in which the boom arm is positioned as shown in  FIG. 4  and spray is illustrated from the nozzle of the boom arm; 
           [0025]      FIG. 6A  is a rear or back view of the cart sprayer of  FIG. 1  in which the boom arm is positioned as shown in  FIG. 4 ; 
           [0026]      FIG. 6B  is a bottom view of the cart sprayer of  FIG. 1  in which the boom arm is positioned as shown in  FIG. 4 ; 
           [0027]      FIG. 7  is a view of the cart sprayer of  FIG. 1  taken from the front with the tank removed showing the front side of a panel of the cart sprayer; 
           [0028]      FIG. 7A  is a broken view of the cart sprayer of  FIG. 1  taken from the rear with the back panel removed showing the pump and hoses coupled thereto as shown in  FIG. 6A  having the tank outlet port to the pump inlet provided by a T-shaped conduit with an opening providing a drain; 
           [0029]      FIG. 7B  is a broken cross-sectional view of the T-shaped conduit of  FIG. 7A  in which the opening providing the drain is closed by a cap; 
           [0030]      FIGS. 8A and 8B  are two exploded perspective views of the cart sprayer of  FIG. 1  taken from the front and rear, respectively; 
           [0031]      FIG. 9  is a schematic diagram of the parts of the hydraulic circuit of the cart sprayer of  FIG. 1  mounted on the plate of  FIG. 7  attached to the back of the tank of the cart sprayer; 
           [0032]      FIG. 10  is a schematic diagram of the electric circuit of the cart sprayer of  FIG. 1  which is mounted on the plate attached to the back of the tank; 
           [0033]      FIG. 11  is a perspective view of the cart sprayer of  FIG. 1  having an exploded view of the boom arm mechanism for positioning the ground spray nozzle selectively at any one of the positions of the boom arm shown in  FIG. 2, 3 or 4 ; 
           [0034]      FIG. 11A  is a partial view of  FIG. 11  to show the exploded view of the assembly of the boom arm mechanism in more detail; 
           [0035]      FIG. 12A  is a cross-sectional view taken along line  12 A- 12 A of  FIG. 1  in the direction of arrows at the end of such line showing part of a mechanism for releasably locking the boom arm of  FIG. 1  at each of its pivot positions depicted in  FIGS. 2, 3, and 4 , respectively; 
           [0036]      FIG. 12B  is a partial cross-sectional view taken along line  12 B- 12 B of  FIG. 2  in the direction of arrows at the end of such line of the mechanism for releasably locking the boom arm of  FIG. 1  when locked at one of the positions associated with  FIG. 2 ; 
           [0037]      FIG. 13  is a partial view from the front of the cart sprayer of  FIG. 1  in which the boom arm of  FIG. 1  is disposed in an alternative position for storage or transportation of the cart sprayer; 
           [0038]      FIG. 14  is a broken view of  FIG. 4A  showing another mechanism for releasably locking the boom arm of  FIG. 1  that may be used for locking the boom arm at each of its pivot positions, rather than the mechanism shown in  FIGS. 12A and 12B ; and 
           [0039]      FIG. 15  is a partial cross-sectional view taken along line  15 - 15  of  FIG. 3  in the direction of arrows at the end of such line of the boom arm, but with the mechanism of  FIG. 14  for releasably locking the boom arm of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0040]    Referring to  FIGS. 1, 2, 3, 4, 4A, 4B, 5, 5A, 6A, and 6B , a cart sprayer  10  having a tank (or housing)  12  for carrying spraying liquid (or fluid) is shown, such sprayer  10  being shown as an exploded assembly in  FIGS. 8A and 8B . A filling cap  14  is provided to the top or crown of tank  12  via a threaded collar  20  ( FIGS. 8A and 8B ) about an opening  20   a  in the center of the crown of the tank. Tank  12  has upper and lower tank sections  16  and  18 , respectively, spaced from each other to define a recess  22 . Such recess  22  being best shown in  FIGS. 1, 5, and 8A . The front of tank sections  16  and  18  are generally hemi-cylindrical, while the back of the tank sections  16  and  18  are flat, but for recesses  23   a  and  23   b,  and channel  23   c  ( FIG. 8B ). Tank  12  may be of injection blow molded plastic material. 
         [0041]    The recess  23   a  along the back of the top tank section  16  accommodates pump hydraulic components, such as a two-way valve  28  and a pump  26 , which are disposed along the interior side or surface of a plate  24  as best shown in  FIG. 7  with the tank  12  removed. Pump  26  is preferably a demand pump with an electric motor, such as available, for example, from Precision Spray Equipment, a Division of Green Leaf, Inc. of Fontanet, Ind., U.S.A., but other electrically powered pump units may be used. Plate  24  is attached to the back of top tank section  16  by four bolts or screws  25   a,  via holes  25   b,  into threaded holes  25   c  molded along tank  12  ( FIGS. 6A, 7, and 8B ). Plate  24  is preferably L-shaped in which a top part  24   a  of the plate extend partially along the top of tank  12 , and the rest of plate  24  extends perpendicular to part  24   a  along the back of tank  12 . Depending on the extent the L-shaped part  24   a  of plate  12  extends along the top of tank  12 , a portion of part  24   a  may be curved to accommodate collar  20   a  of tank  12  such as shown in  FIGS. 2-4 . 
         [0042]    Electrical components may be disposed on the exposed, side, or exterior surface of plate  24  as shown in  FIG. 6A . These electronic components include, for example, a shoe shaped connector (or receptacle)  46  ( FIG. 8B ) which is mounted on the back of plate  24  to releasably hold a battery  48 , preferably of the rechargeable Lithium-ion type, for powering the electric motor of the pump  26 . The battery  48  can be removed and replaced in the shoe connector  46 . An ON-OFF switch  124  is also provided to enable and disable power to the motor or pump  26 . The electrical components will be described later in more detail in connection with  FIG. 10 . 
         [0043]    The tank  12  is in an assembly with a frame  30  having two main parts  32  and  34 . A shaft  42  extends from (or attaches to) the rear part  34  of the frame  32  and rearwardly extends upward at an angle for connection with handles or a handle section provided by two push bars  44 . Grips  45   d  for operator hands may be received along the upper ends of push bars  44 . As best shown in  FIGS. 8B and 12A , bolts and nuts  43   c  may be used to attach shaft  42  to rear part  34  through holes  43   a  and  43   b  that extend through rear part  34  and shaft  42 , respectively. To attach shaft  42  to push bars  44 , bolts and nuts  45   c  may be used through holes  45   a  and  45   b  that extend through shaft  42  and lower end of push bars  44 . The ON-OFF switch  124  is preferably mounted along shaft  42  near push bars  44 , but may optionally be mounted to the back of plate  24 . A switch holder  125  may be used to mount switch  124  to shaft  42 , where screws or bolts  125   a  or other mechanism mounts the holder  125  to the top end of shaft  42  near the lower end of push bars  44 . The tank  12  also has an attached boom assembly  36  for a nozzle  38  which sprays toward a surface, such as the ground  40 . Thus, the tank  12  may be considered the center of an integrated assembly of the parts of the cart sprayer  10 . 
         [0044]    The frame section  32  is U-shaped in the center thereof so that it can be received and fit into recess  22  and effectively hangs the tank  12  on the frame  30 . Two bolts or screws  59   a  on either side of tank  12  extend through holes  59   b  in frame section  32  into threaded holes  59   c  molded along tank  12 . For purpose of illustration, one of such bolts  59   a  is shown in  FIG. 1 . Optionally, an additional bolt may be attached to the front of frame  30  to tank  12 . Also, frame section  32  has legs  33  which bend forwardly and receive bearings  50 , via openings  51 , carrying a shaft  52  on which wheels  54  are journal mounted by providing axles  57  which rotate at each end of the shaft  52  upon bearings  50 . Each wheel  54  has a hole extending through a central shaft  55   a  for mounting the wheel onto one of the two rotational axles  57 . The end of each axle  57  has a hole  57   b  extending there through for receiving a cotter pin  55   d  after the wheel  54  is received on its axle  57  and extends through a washer  55   e.  This allows each wheel  54  to freely rotate upon its respective axle  57  (or to rotate with axle  57  upon bearings  50 ), while the cotter pins  55   d  retain the wheels  54  on axles  57 . Less preferably where free rotation upon its axle is not desired, one or both wheels  54  may instead, or in addition to cotter pins  55   d,  be bolted (fixed) to its axle  57 , such as using a bolt  55   b  extending through a hole  55   c  through central shaft  55   a  and a hole  57   a  in axle  57 , to a tightened nut for fixing the wheel  54  onto the axle  57  so that wheel  54  and its associated axle  57  rotate together. Other mechanisms for mounting wheels  54  may also be used. The cart sprayer  10  assembly is therefore mounted on wheels  54  and can be pushed (or pulled) using push bars  44  along ground  40 . 
         [0045]    The rear section  34  of the frame  30  has legs which are connected to the legs of the front frame part  32  using bolts  35   c,  via holes  35   a  and  35   b,  along sections  32  and  34 , respectively, to nuts  35   e  ( FIGS. 4A, 4B, 5 and 8B ). Each bolt  35   c  extends through a plastic spacer or washer  35   d  located between sections  32  and  34  when so joined together. The ends  60  of the legs of the rear frame section  34  form feet on which the cart sprayer  10  can be rested on the ground  40  (see  FIG. 1 ). Rubber or plastic caps  61  may be received in ends  60  ( FIGS. 1 and 8B ). 
         [0046]    Optionally, cart sprayer  10  may be pulled with an optional “T” shaped towing knuckle  58  as shown in dash lines in  FIGS. 1 and 8A . The two opposing ends of the lateral leg  58   a  of knuckle  58  may be attached across the back of frame  30 , such as using bolts  35   c,  which attach frame sections  32  and  34  together, via holes provided at such opposing ends. When cart sprayer  10  is towed by coupling to leg  58   b,  shaft  42  may be removed at its bolts  43   c  if needed from the rest of frame  30 , and ON-OFF switch  124  relocated for placement on the outside of panel  24 , and wand  98  maintained in the vehicle which is towing the cart sprayer  10 . Coupling to the vehicle by knuckle  48  (or other attachment mechanism) may be in a manner similar to typical towed agricultural equipment, and thus details with respect to such coupling are not described herein. 
         [0047]    Boom assembly  36  has a curved back plate  70  and a slotted bracket  72  from which extends a boom arm  76 . The assembly is best shown in the exploded view of  FIG. 11 , which is shown in more detail in  FIG. 11A . Bracket  72  and back plate  70  may be a molded part or may be assembled together and attached to tank  12  with fasteners, such as bolts or screws  74 , via holes  74   a  in back plate  70 , into threaded holes  74   b  ( FIG. 8A ) molded along the curved front of the upper tank section  16 . Boom arm  76  is preferably a metal (e.g., aluminum) bar with openings or spaces along its length for lightening its weight. For purposes of illustration, boom arm  76  is shown positioned above bracket  72  in  FIGS. 11 and 11A . The rear end of arm  76  is received in a slot  73  of bracket  72 . Bracket  72  has upper and lower walls  73   a  and  73   b,  respectively, defining slot  73 . A hole  78  in the rear or proximate end of the arm  76  is rotationally captured by a pin  80  which passes through a central hole  82  of bracket  72 , where such hole  82  passes through both walls  73   a  and  73   b  through the middle of the bracket  72 . Thus, an upper part of hole  82  extends through the middle of a cross member  84  along the top of bracket  72 , and lower part of hole  82  extends through the middle of an identical mirror cross-member  84  along the bottom of bracket  72 . Pin  80  passes though both hole  82 , via slot  73  and opening  78  of arm  76 , and is then captured by a cotter pin  88  via a hole  89  through the bottom end of pin  80  (see  FIG. 12B ). 
         [0048]    The slot  73  in bracket  72  permits pivotal movement of the boom arm  76  about pin  80  in hole  82 , such as denoted by arrows  79  ( FIG. 2 ), over an arc at or slightly more than 180 degrees so that the boom arm  76  can be positioned at any of the selected positions 90 degrees apart at the sides and the front of the sprayer  10 , as shown best in  FIGS. 2, 3 and 4 . Thus, pin  80  provides a pivot member for rotating boom arm  76  in bracket  72 . In other words, boom arm  76  position shown in  FIG. 2  is aligned to the front of the sprayer, such as useful for towing of the cart sprayer  10 , and boom arm  76  position in  FIGS. 3 and 4  are for right and left side spraying, respectively, as useful for manual pushing of cart sprayer  10 . The three positions of boom arm  76  are 90 degrees apart from each other. The side positions of boom arm  76  in  FIGS. 3 and 4  are 180° apart from each other and perpendicular to the path of travel of the sprayer  10 . 
         [0049]    The front or distal end of the boom arm  76  has an opening  77   a  ( FIG. 11A ) for receiving the spray nozzle  38 . Preferably, the nozzle  38  has an orifice through which the spray liquid passes out of the nozzle in a pattern providing a flat fan shape denoted by a spray  81  toward ground  40  in  FIGS. 3 and 4 . Spray  81  in  FIGS. 3 and 4  is along a dimension aligned with the length of boom arm  76 . For purposes of illustration, spray  81  is depicted in the figures when cart sprayer  10  is not in motion forwards or backwards along wheels  54 . Preferably, spray  81  is in a wide angle  81   a  (see  FIG. 5A ), such as 90 degrees, along a distance on ground  40  extending under the boom arm  76  approximately 2 inches away from a virtual line  83  ( FIGS. 3 and 4 ) perpendicular to spray  81  and aligned with the outer edge of the closest wheel  54 , to approximately 3 to 4 feet away from the nozzle  38 . However, other range of the spray  81  may be used by providing different nozzles or tips along the outlet end of nozzle  38 . While  FIG. 5A  shows spray  81  along angle  81   a  for left side spraying, spray  81  may similarly be provided along a mirrored one of angle  81   a  of  FIG. 5A  along the right side of sprayer of  FIG. 3  for right side spraying. Thus, a spray pattern is provided which is principally to the either right side ( FIG. 3 ) or left side ( FIG. 4 ) of the sprayer  10  as desired by operator selected boom arm position, which is directed away from the path of travel of the cart sprayer  10  to ensure no passage or trampling over any fresh spray on the ground as the sprayer  10  travels along its path. Although the fan spray  81  is shown as being along the length of boom arm  76  ( FIGS. 3 and 4 ), the direction of the fan spray  81  may set at an orientation approximately perpendicular, or non-perpendicular, so that spray is directed towards the ground  40  as desired. Optionally, nozzle  38  may be rotationally mounted to boom arm  76  so that it can be manually rotated in position to obtain the desired fan spray  81  along ground  40  with respect to sprayer  10 . Less preferably, when boom arm  76  is positioned as shown in  FIG. 2  in front of cart sprayer  10  and boom arm  76  is aligned with the path of travel of the cart sprayer  10 , the nozzle  38  or the tip along the outlet end of such nozzle is replaced with a flood or fan spray  81   b  perpendicular to the length of boom arm  76 . If nozzle  38  is rotationally mounted to boom arm  76 , it may be rotated to a position to obtain such spray orientation of  FIG. 2 . 
         [0050]    Boom arm  76  is slidable along the interior of upper and lower walls  73   a  and  73   b,  respectively, of slot  73  of bracket  72  about its pivotal range of motion by rotation along an axis of rotation extending through the center of the pin  80  and hole  78 . The boom arm  76  has a mechanism for releasably locking the arm at each of its pivot positions depicted in  FIGS. 2, 3 , and  4 , which is provided by either a detent mechanism of  FIGS. 12A and 12B , or a pin mechanism of  FIGS. 14 and 15 . For purposes of illustration, the mechanism for releasably locking boom arm  76  is not shown in the exploded views of  FIGS. 8A and 8B . 
         [0051]    As shown in the cross-sectional views of  FIGS. 12A and 12B , the detent mechanism has a spring plunger  76   a  mounted in a hole  76   b  of boom arm  76  so that a ball (pin or member)  76   c  of the spring plunger  76   a  under bias of its internal spring  76   d  can be captured in each one of three holes  75   a,    75   b,  and  75   c  at 0, 90, and 180 degrees, respectively, as the boom arm  76  with its plunger  76   a  moves along an arc about its axis of rotation to temporarily fix boom arm  76  at right, center, and left positions shown in  FIGS. 3, 2, and 4 , respectively. Holes  75   a,    75   b,  and  75   c  (also referred to herein as  75   a - c ) each extend through lower wall  73   b  of slot  73  and are spaced at locations so that holes  75   a - c  provide openings along the lower wall  73   b  of slot  73  so that ball  76   c  can slide along the lower wall  73   b  into and between holes  75   a - c  when boom arm  76  is moved manually by the operator. In this manner, a detent mechanism is provided that temporarily keeps the boom arm  76  in a desired pivot position relative to tank  12  where the boom arm can be released by applying a rotational force (or torque) to the boom arm. Holes  75   a,    75   b  and  75   c  may extend through upper and lower slot walls  73   a  and  73   b,  however their placement in upper slot wall  73   a  is optional where the detent mechanism described herein is used. 
         [0052]    Holes  75   a,    75   b,  and  75   c  along lower slot wall  73   b  are preferably of a diameter to capture ball  76   c,  but with applied manual torque to boom arm  76  allows the ball  76   c  to slide backwards against bias of spring  76   b  when slid against the upper edge of each hole  75   a - c  up onto lower wall  73   b  to release the ball from such hole when desired. In other words, to select a different boom arm  76  pivot position, manual pressure along the arm  76  can pivot it towards a different position by pushing ball  76   c  of the spring plunger  76   a  backwards and away from one of holes  75   a - c,  sliding ball  76   c  along lower wall  73   a  of slot  73 , and letting the ball  76  under bias of spring  76   d  move forward into a different one of holes  75   a - c  along slot  73 . Additional releasable locking positions for boom arm  76  may similarly be provided by providing additional one(s) of holes  75   a - c  at other degrees with same or different nozzle  38  or outlet tip as desired. Optionally holes  75   a - c  may be provided by recesses along upper wall  73   a  which can similarly releasably capture ball  76   c  of spring member  76   a  if positioned with respect to such holes in the same manner as along lower wall  73   b.  Other mechanisms for releasably locking the boom arm  76  at a selected pivot position may be used, such as described later below in connection with  FIGS. 14 and 15 . 
         [0053]    The sprayer  10  uses several flexible hoses which extend from two outlets  109  of the two-way valve  28 , where one of such outlets  109  is shown in  FIG. 7 , and both are shown in  FIG. 8B . The lower one of outlets  109  is in fluid communication via a hose  100  to nozzle  38  in the boom arm  76 , and the upper one of outlets  109  is in fluid communication via a hose  108  with a sprayer wand (or gun)  98  having a nozzle  106 . Spray wand  98  is described hereinafter in greater detail. As shown in  FIG. 1 , hose  100  extends via an opening  77   b  in boom arm  76  along the top of the arm to a coupler  100   a,  which connects the hose to a right angle input port  101  of nozzle  38 . 
         [0054]    Sprayer wand  98  has a spray shut-off with a trigger  104  in its handle portion to allow pressurized liquid to flow through the wand&#39;s tubular shaft or extension  99  to a spray nozzle  106  when trigger is depressed by the operator holding the wand. Nozzle  106  provides a spray head at the distal end of shaft  99  of sprayer wand  98 . The shut-off may refer to a valve in the handle portion which operates responsive to trigger  104  to control liquid flow down tubular shaft  99  to distal nozzle  106 , as typical of sprayer wands. An example of sprayer wand  98  with such a shut-off is shown in U.S. Pat. No. 8,939,387, issued Jan. 27, 2015, which is incorporated herein by reference, in which an optional distal nozzle upon a tubular extension is utilized with or without the additional valve and supporting structure provided therein. Other sprayer wands or spray guns than that shown in the figures may receive liquid from hose  108 , such as those used with backpack sprayers manufactured by Chapin Manufacturing, Inc. of Batavia, N.Y. 
         [0055]    Spring snap in holders  102  attach along shaft  42  to releasably hold spray wand  98  along its shaft  99  when not in use. The spray wand  98  may alternatively be releasably held by its shaft  99  being received into an optional slot  105  through a raised portion  35  of cap  14 , as desired by the operator. Bolts  103   a  and nuts  103   b  may be used to attach holders  102  through holes along shaft  42  ( FIG. 8B ). The nozzle  106  may have a spray orifice of circular cross-section to produce a generally conical spray, as typical of a spray gun, but a nozzle may be provided with a spray orifice providing other cross-section spray shapes as desired. Hose  108  may be coiled along the top of top tank section  16  around the cap  14  of the tank  12 . Hose  108  connects via a coupling on the two-way valve  28  along the front or inside surface of plate  24  (see  FIGS. 4 and 7 ). The tank  10  is shaped to provide a channel (or groove)  23   c  for passage of the hose  108  end coupled to valve  28  via slot  24   b  in top L-shaped part  24   a  of plate  24 . By selection of two-way valve  28  position, pump  26  supplies spray liquid to either nozzle  38  in the boom arm  76 , or to sprayer wand  98 , as described below. 
         [0056]    Referring to  FIG. 6A , a handle or lever  110  of two-way valve  28  is mounted on the back, outside, or exposed side or surface of the plate  24  via an opening in the plate. Handle  110  provides a selector for operating the two-way valve to its two positions. With the handle  110  in the vertical or up position as shown in  FIG. 6A , the two-way valve  28  connects the pump  26  to the nozzle  38  at the front end of the boom arm  76 , via hose  100  and coupler  100   a.  With the handle  110  in its alternative position turned 90 degrees to horizontal (i.e., handle  110  turned to the right in  FIG. 6A ), the two-way valve  28  connects the pump  26  to the sprayer wand  98  via hose  108 , so that when trigger  104  is depressed, liquid provided via hose  108  can pass through nozzle  106 , as typical of a spray gun. Thus, hydraulic communication of liquid to either a first path to sprayer wand  98  or a second path to the boom nozzle  38  can be selected for spraying by turning handle  110  of the two-way valve  28  as desired, while hydraulic communication ceases along the unselected path. When sprayer wand  98  is selected, hose  108  may be uncoiled to enable the wand to be carried over to wherever spraying with the wand  98  is to be carried out. Supply liquid provided to two-way valve  28  is inputted to pump  26  from the tank  12  through another hose  118  (see  FIG. 7 ). A hydraulic schematic of fluid flow in sprayer  10  using liquid pumped by pump  26  from tank  12  is shown in  FIG. 9  to illustrate hydraulic fluid communication of the above described components. 
         [0057]    As shown in  FIG. 7 , hose clamps  27  are provided along panel  24  for connecting hoses  100  and  108  to the two-way valve  28  outlets  109 , hose  29  from pump  26  outlet or output  26   a  to valve  28  inlet  111 , and hose  118  to pump  26  inlet  26   b.  Coupler  118   a  connects lower end of hose  118  to tank  12  outlet port  119  using hose clamp  118   b  (see  FIG. 7 ), so that pump  26  inlet is in fluid communication with tank  12  liquid. The preferred connection of hose  118  to tank  12  is shown in  FIGS. 6A, 7A, and 7B . Hoses  100 ,  108 ,  29 , and  118  represent conduits for communication of liquid. Hose  100  is flexible and movable in boom arm opening  77   b  to allow freedom to pivot boom arm  76  as described herein, and hose  108  is flexible to allow freedom of movement of wand  98  by a user when removed from holders  102  to shaft  42  or slot  105 . 
         [0058]    Referring to  FIGS. 6A, 7A, and 7B , tank outlet port  119  is preferably provided by a T-shaped conduit as best shown in  FIG. 7B  having a horizontal conduit  119   a  into tank  12  at or near the base of the tank  12  as shown in  FIG. 7B  (see arrow indicating direction of fluid flow when drawn by pump  26 ), a vertical downward extending externally threaded opening  120  which provides a drain for tank liquid when present, and a barbed opening  119   b  opposite opening  120  onto which the lower end of hose  118  is received. When the drain is not is use, it is closed by an internally threaded cap  121  over opening  120 . Cap  121  may be retained by a tether  122  coupling the cap to a ring  123  about the base of opening  120 . This allows liquid flow when drawn by pump  26  into conduit  119   a  and up vertical opening  119   b  via hose  118 . For purposes of illustration, such preferred T-shaped conduit providing outlet port  119  is not shown in  FIGS. 8A and 8B . 
         [0059]    Recess  23   b  along the tank  12  below recess  23   a  is provided for hoses  100  and  118  under the bottom of panel  24 , as shown in  FIGS. 6A and 8B . After extending downwards along recess  23   b,  hose  100  then extends under the bottom of the tank  12  ( FIG. 6B ) to the front of the tank for connection to nozzle  38  ( FIG. 4A ). Preferably hose  100  extends through an aperture of a ring (or loop)  95  that extends downward from the bottom of tank  12  for supporting and positioning hose  100 . Recesses  23   a  and  23   b,  and channel  23   c  may be formed when tank  12  is molded, along with optional support ring  95 . Screws  31   a  ( FIG. 8B ) may be provided for mounting components to panel  24  via holes provided along such panel (nuts may optionally be used with such screws), such components include mounting pump  26  via holes  31   b  into four threaded holes along panel  24 , and for similarly mounting valve  28  and battery shoe or receptacle  46  to panel  24 . Panel  24  is shown in  FIG. 6A  with a preferred position of the panel  24  with respect to tank  12 , and preferred position of the battery  48  on the panel. However, the battery  48  may be positioned differently on the panel in its receptacle  46  than shown in  FIG. 6A  to enable external access by a user. 
         [0060]    The pump  26  may be a diaphragm pump having a flexible diaphragm and a pair of check (one-way) valves. One of the check valves is associated with the inlet to the pump and the other check valve is associated with the outlet of the pump. The diaphragm is flexed cylindrically by a cam mechanism, which may be an elliptically shaped disc rotated by the electric motor of the pump unit. When flexed in one direction, the diaphragm is on the suction part of its cycle and liquid is sucked into the pump because the check valve connected to its outlet is closed and the check valve associated with the pump inlet is open to allow liquid flow to the pump. Conversely when the diaphragm is flexed in the other direction on the pressure part of the cycle, the check valve connected to the outlet is opened and the check valve connected to the inlet is closed, thereby providing pressurized liquid through the outlet to the two-way valve  28  for spraying either by the nozzle  38  on the boom arm  76  or the nozzle  106  on the end of the sprayer wand  98  as selected by handle  110 . 
         [0061]    Referring to  FIG. 10 , an electrical schematic is shown having battery  48  connected via ON-OFF switch  124 . Panel  24  facilitates access to other components of the electric circuit shown in  FIG. 10 . Wires  125   c  connect by tabs or connectors  125   b  at ON-OFF switch  124  (see  FIG. 8B ). Such wires  125   c  extend from ON-OFF switch  124  to the circuit along panel  24  via shaft  42  (see  FIGS. 6A and 6B ). To turn ON the motor of the pump  26 , the ON-OFF switch  124  is placed in its ON position. Current powering the pump  26  flows through a low voltage cut-off circuit  126 , and a pressure switch  128 , on the output side of the pump (see  FIG. 7 ), to the pump  26  motor and then back to battery  48 . The low voltage cut-out circuit  126  senses the voltage across the battery  48 . The low voltage cut-off circuit  126  has a switch which opens the circuit connected to pump  26  motor to cease operation of pump  26  motor (and spraying if occurring via nozzle  38  or  106 ) since low voltage condition provides insufficient power for effective pumping and spraying. Optionally, the low voltage cut-off circuit  126  may have a warning light, such as a red LED lamp, mounted on the rear of panel  24  which indicates the low voltage condition. The pressure switch  128  is part of the pump  128 , as shown in  FIG. 9 , it senses the pump output pressure so that current is allowed to flow to pump  26  when at or below a psi threshold level, and when such threshold psi level is exceeded disables current to pump  26 , as typical of a pressure switch on demand pumps. For example, such threshold level is  50 psi. Pressure switch is useful when sprayer wand  98  is selected by the operator via handle  110  for spraying liquid from tank  12 , so as to avoid excessive pressure build up in the pump when not spraying via its nozzle  106 . 
         [0062]    When sprayer  10  is not being used, the boom arm  76  may be moved to a storage/transport position in bracket  72  as shown in  FIG. 13  using a hole  112  ( FIGS. 1 and 4A ) provided at (or approximately) the middle of boom arm  76 . To move boom arm  76 , pin  80  is removed from bracket  72  of boom mechanism  36  by removing cotter pin  88  ( FIG. 12B ) from hole  89  of pin  80 , and then manually lifting pin  80  upwards from central hole  82  of bracket  72 . Boom arm  76  is positioned in slot  73  of bracket  72  so that hole  112  of the boom arm is aligned with central hole  82 , and then placing pin  80  in hole  82 , via hole  112 , so that pin  80  again extends in hole  82  through bracket  72  via slot  73 . If desired, cotter pin  88  is placed back in hole  89  of the pin  80  to retain the boom arm  76  to bracket  72  in its mid position shown in  FIG. 13 . This minimizes (or avoids) rotational motion of boom arm  76  in bracket  22 , and reduces the extent boom arm  76  extends outward along right and left sides of sprayer  10  to one-half (or approximately one-half) of the extent boom arm  76  normally extends from tank  12  as shown in other figures, thereby reducing risk of damage to boom arm  76  (as well as nozzle  38 ) when sprayer  10  is stored or transported. Also, use of pin  80  in bracket  72  further enables boom arm  76  to be removable from sprayer  10  if needed for replacement. Boom arm  76  is shown as a solid member in  FIG. 13  with openings  77   a,    77   b,    78 , and  112  described earlier, preferably boom arm  76  has other openings (or grid structure) along its length for lightening its weight as shown in other figures. 
         [0063]    Optionally, and preferably, a pin mechanism for retaining the boom arm  76  position as shown in  FIGS. 14 and 15  is used instead of the detent mechanism for releasably locking boom arm  76  described earlier in connection with  FIGS. 12A and 12B . In such preferred mechanism for releasably locking pivotal movement of boom arm  76  in bracket  72 , a pin (or retainer member)  116  extends into slot  73  of bracket  72  via one of holes  75   a,    75   b  and  75   c  of upper wall  73   a  of bracket  72  into an opening (or hole)  117  ( FIG. 15 ) of boom arm  76  provided along arm&#39;s grid structure (previously occupied by spring plunger  76 — FIG. 12B ) to retain the boom arm pivot position when pivoted at right, center, and left positions, respectively. The pin  116  is shown as extending partially in slot  73  to engage boom arm  76  via opening  117 , but may be of a length such that pin  116  extends through slot  73  partially into or through such one of holes  75   a,    75   b,  or  75   c  in the lower wall  73   b  of bracket  72  associated with desired boom arm pivot position. While boom arm  76  in the example of  FIG. 14  is shown locked by pin  116  via hole  75   c  of bracket  72  for spraying along the left side of travel of sprayer  10 , pin  116  may be removed from hole  75   c  and similarly used in hole  75   a  or  75   b  with boom arm  76  aligned for receiving such pin  116  via opening  117  of boom arm  76 . Pin  116  is shown received in hole  75   a  in  FIG. 15 . To move the boom arm  76  to a different pivot position, pin  116  is manually lifted and removed from boom arm  76  and bracket  72  from its original one of holes  75   a - c  of upper wall  73   a  (and optionally lower wall  73   b ) of bracket  72 , boom arm  76  is pivoted (rotated) about pin  80  so that opening  117  of the boom arm  76  is aligned in slot  73  with a different one of holes  75   a - c,  and then pin  116  is received in such different one of holes  75   a - c  and opening  117  to lock the boom arm  76  at its new pivot position. Thus, each of three holes  75   a,    75   b,  and  75   c  at 0, 90, and 180 degrees, respectively, can be used with pin  116  as the boom arm  76  moves along an arc about its axis of rotation set by pin  80  to temporarily lock boom arm  76  at right, center, and left positions shown in  FIGS. 3, 2, and 4 , respectively. Additional or different ones of such holes may be provided along this arc in bracket  72  at other degrees than those associated with holes  75   a - c,  if desired, at which boom arm  76  may pivot to and be releasably locked by pin  116  via opening  117  of the boom arm. 
         [0064]    Pin  116  of the releasably boom locking mechanism may be coupled to a lanyard or tether  113  (e.g., such as a flexible cable, wire, or cord) to sprayer  10 . For example, tether  113  has two ends  114   a  and  114   b.  End  114   a  is attached to coupler/boss  115  extending about upper end of hole  82 , and the other end  114   b  passes through a hole at the top end of pin  116 . Although such tethering mechanism is shown, other mechanisms for tethering pin  116  may be used. Also, as in the case of pin  80 , pin  116  may have a head that is larger in diameter than holes  75   a - c,  so as to dispose pin  116  in holes  75   a - c  as desired with or without tether  113 . As best shown in  FIG. 15 , the diameter of holes  75   a - c  and opening  117  of the boom arm  75  are the same (or approximately the same), and pin  116  is of a diameter slightly smaller than holes  75   a - c  and opening  117 . Bracket holes  75   a - c  for receiving pin  116  are co-axial with each other as well as with hole  82  for pin  80 . 
         [0065]    There has been described a cart sprayer having improved mechanical and electrical design features which provide the sprayer with better performance than such sprayers heretofore proposed or available on the market. Variations and modifications of the herein described cart sprayer within the scope of the invention will undoubtedly suggest themselves to those skilled in the art. For example, the components mounted on panel  24  may be disposed differently than shown in the figures so long as pump  26  and valve  28  are disposed to enable fluid communication as described herein via hoses  109 ,  100 , and  118  as desired by selection of handle  110  position during operation of sprayer  10 . Accordingly, the foregoing description should be taken as illustrative, and not in a limiting sense.