Abstract:
A wheelbarrow includes three wheels so that it may be pushed without being lifted, thereby minimizing the potential for operator injuries due to lifting the wheelbarrow. A braking mechanism including a lever having one end for engaging a user&#39;s hand or foot, and another end for engaging a sprocket secured to one of the wheels, may be used to resist movement of the wheelbarrow when such movement is not desired.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims the benefit of U.S. Provisional Patent Application No. 60/573,887, filed May 24, 2004, entitled “Three-Wheeled Braking Wheelbarrow.” 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to wheelbarrows. More specifically, the present invention provides a wheelbarrow having three wheels, and a brake for at least one of the three wheels.  
         [0004]     2. Description of the Related Art  
         [0005]     Conventional wheelbarrows typically include a single wheel and a pair of legs. When the legs are resting on the ground, the legs resist movement of the wheelbarrow. To move the wheelbarrow, the legs must be lifted off the ground throughout the entire movement. This constant lifting causes operator fatigue and increases the risk of injury to the operator. Additionally, the single wheel of such a wheelbarrow can increase the difficulty in moving the wheelbarrow if the load therein is off balance.  
         [0006]     The presently available three-wheeled wheelbarrow is presently offered by Prestar Manufacturing, and is disclosed in U.S. Patent Application No. US 2004/0041361 A1, published on Mar. 4, 2004. One embodiment of this wheelbarrow includes a pair of plates having J-shaped channels mounted on each leg. An axle having a wheel at each end passes through the J-shaped channels. Placing the axle in the shorter portion of the J-shaped channel allows the wheelbarrow to roll along three wheels. Placing the axle in the longer portion of the J-shaped channel permits the legs of the wheelbarrow to touch the ground, thereby resisting movement of the wheelbarrow. This wheelbarrow still requires some lifting prior to moving the wheelbarrow, and then to prevent movement of the wheelbarrow after it is pushed to the desired location.  
         [0007]     Accordingly, there is a need for a wheelbarrow having at least three wheels so that it does not to be lifted in order to be pushed. Additionally, there is a need for a wheelbarrow having a braking mechanism that does not require lifting the wheelbarrow.  
       SUMMARY OF THE INVENTION  
       [0008]     The present invention provides a wheelbarrow or other wheeled cargo-carrying cart having three wheels, and having a brake mechanism for resisting movement of the wheelbarrow.  
         [0009]     For the purpose of this description, a wheeled cargo-carrying cart is defined as any wheeled implement having a platform, bucket, bed, seat, or any other cargo-holding means secured to a frame, having a plurality of wheels secured thereto, and being structured to be manually pushed or pulled from one location to another. A wheelbarrow is a preferred embodiment of a wheeled cargo-carrying cart with which the present invention may be used, and the invention is described and illustrated herein based on this example. In other embodiments, the wheeled cargo-carrying cart may be structured to transport human or other living cargo, as in the example of a wheelchair.  
         [0010]     A wheelbarrow of the present invention includes containers secured within a frame. The frame includes a front wheel and a pair of rear legs depending downward therefrom, and a pair of handles extending rearward therefrom. A pushbar extends upward from the handles.  
         [0011]     An axle is rotatably secured to the legs, with a wheel disposed on each end of the axle. At least one of the wheels includes a brake mechanism for resisting movement of the wheelbarrow. The brake includes a lever pivotally secured to the frame, and having one end structured to engage one of a plurality of cutouts within a sprocket that is secured to at least one of the wheels. The other end of the lever is structured to be moved towards and away from the sprocket by either the operator&#39;s hand or foot. The handle also includes means for securing the handle in either a braking position or a released position, with one preferred means being a nylock nut as part of the handle&#39;s pivot, for providing friction to the pivoting of the handle.  
         [0012]     The present invention therefore provides a wheelbarrow having three wheels, that may be pushed from one location to another without lifting it. The present invention further provides a wheelbarrow having a braking means for resisting movement of the wheelbarrow when such movement is not desired, and which does not require lifting of the wheelbarrow.  
         [0013]     Accordingly, it is an object of the present invention to provide a wheelbarrow having at least three wheels, so that it may be pushed without being lifted.  
         [0014]     It is another object of the invention to provide a wheelbarrow having a braking mechanism to resist movement of the wheelbarrow when such movement is not desired.  
         [0015]     It is a further object of the invention to provide a wheelbarrow having a braking mechanism that may be configured for operation by the user&#39;s hand or foot.  
         [0016]     These and other objects of the invention will become more apparent through the following description and drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]      FIG. 1  is a side perspective view of a wheelbarrow according to the present invention.  
         [0018]      FIG. 2  is a rear perspective view of the legs and wheels of a wheelbarrow according to the present invention.  
         [0019]      FIG. 3  is a perspective side view of a braking mechanism for a wheelbarrow according to the present invention.  
         [0020]      FIG. 4  is a side perspective view of a braking mechanism for a wheelbarrow according to the present invention.  
         [0021]      FIG. 5  is a side view of a braking mechanism for a wheelbarrow according to the present invention.  
         [0022]      FIG. 6  is a side perspective view of the partially disassembled components of a braking mechanism for a wheelbarrow according to the present invention.  
         [0023]      FIG. 7  is a side perspective of a wheel for a wheelbarrow having a braking mechanism of the present invention.  
         [0024]      FIG. 8  is a rear perspective view of an alternative embodiment of a braking mechanism for a wheelbarrow according to the present invention. 
     
    
       [0025]     Like reference characters denote like features throughout the drawings.  
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0026]     The present invention provides a wheelbarrow having at least three wheels, and having a braking means for resisting movement of at least one of the wheels when desired.  
         [0027]     Referring to  FIGS. 1-5 , the wheelbarrow  10  includes a frame  12  supporting a bucket or container  14 . In the illustrated embodiments, the frame  12  includes a pair of elongated beams  16 ,  18  that may be secured together by the front cross beam  20 . A front wheel  22  rotates about an axis  24  secured to a forward portion of the beams  16 ,  18 . The opposite ends of the elongated beams  16 ,  18  terminate in the handles  26 ,  28 . A pair of legs  30 ,  32  depend downward from the elongated beams  16 ,  18 . An axle  34  is pivotally secured to the legs  30 ,  32 , in the illustrated example by the axle bracket  36 . A wheel  38 ,  40  is secured to each end of the axle  34 . In some preferred embodiments, the wheels  38 ,  40  may rotate independently with respect to each other and with the axle  34 . The bucket  14  is disposed above the frame  12 , and has a center of gravity disposed within the triangle formed by the wheels  22 ,  38 ,  40 . A pushbar  42  extends upward from the elongated beam  16 ,  18 , adjacent to the handles  26 ,  28 .  
         [0028]     Referring to  FIGS. 2-6 , the wheelbarrow  10  includes a brake that may be selectively engaged by the user. The brake  44  includes a brake lever  46  pivotally secured to the frame  12 . In a preferred embodiment, the brake lever  46  is pivotally secured to a brake lever bracket  48 , which is itself secure to the leg  30 . In the illustrated example, the pivot  50  between the brake lever  46  and brake lever bracket  48  is formed by a brake passing through a bolt having a nylock nut  52  secured to one end. The tension of the nylock nut  52  may be adjusted to provide a desired level of friction, so that undesired movement of the brake lever  46  is resisted, but the friction may be overcome by the operator when the brake lever  46  must be moved. A pin  54  extends outward from the lower end of the brake lever  46 , towards the wheel  38 . A handle  56  is located at the upper end of the brake lever  46 .  
         [0029]     The wheel  38  includes a sprocket  58  defining a plurality of notches  60 , with each notch being dimensioned and configured to receive the pin  54 . When the brake lever  46  is pulled away from the bucket  14 , the pin  54  is moved into one of the notches  60 , thereby resisting movement of the wheel  38 , and securing the wheelbarrow  10  in place. Moving the brake lever  46  towards the bucket  14  removes the pin  54  from the notch  60 , thereby permitting movement of the wheel  38  and the wheelbarrow  10 . A stop  62  depending outward from the brake lever bracket  48  resists undesired movement of the brake lever  46  substantially farther than that necessary to disengage the pin  54  from the notch  60 .  
         [0030]     Referring to  FIGS. 7-8 , another embodiment of the brake  64  is illustrated. The brake  64  includes a rod  66  having substantially parallel first and second ends  68 ,  70 , and a central section  72  that is angled with respect to the first and second ends  68 ,  70 . The second end  70  is connected to the lower end of a bracket  74 , which is pivotally connected to the brake lever bracket  48  by the pivot  76  at its upper end. The pivot  76  may be formed from a bolt secured to a nylock nut  78 , which is tightened to provide sufficient friction to resist undesired movement of the bracket  74  and rod  66 , without providing enough friction to provide undue resistance to a user applying or disengaging the brake  64 . When the rod  66  is raised so that the bracket  74  engages the stop  62 , the wheel  38  is free to rotate. Pushing down on the first end  68  of the rod  66  pivots the rod  66  and bracket  74  so that the second end  70  engages a notch  60  within the sprocket  58 , thereby resisting movement of the wheel  38 .  
         [0031]     The present invention therefore provides a brake for a three-wheeled wheelbarrow that may, depending upon the embodiment selected, by operated by the user&#39;s hand or foot. The brake resists movement of at least one wheel when engaged, and permits the wheelbarrow to be pushed when disengaged. The present invention therefore minimizes or eliminates the need to lift the wheelbarrow  10  during use, because the wheelbarrow may be pushed to a desired location and then secured at that location through manipulation of the brake instead of by lifting the wheelbarrow. Fatigue and injuries to the user are thereby made less likely to occur.  
         [0032]     While a specific embodiment of the invention has been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the invention which is to be given the full breadth of the appended claims and any and all equivalents thereof.