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BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to an improvement in a snow removal machine propelled by crawler belts.  
           [0003]    2. Description of the Related Art  
           [0004]    In removing snow, snow removal machines are generally used for lessening the labor. A snow removal machine has a rotary snow removing device or a snow removing plate at a front part of its body and is propelled by crawler belts during snow removal. This type of snow removal machine is disclosed in, for example, Japanese Patent Publication No. HEI-6-60482. The snow removal machine has drive wheels at a front part of its body and driven wheels at a rear part of its body. Crawler belts are trained around the drive wheels and driven wheels for serving as running parts.  
           [0005]    In this snow removal machine, since the crawler belts have openings between the drive wheels and the driven wheels, snow may get into the inside of the crawler belts from sideways during snow removing operation. Some of the snow getting into the inside of the crawler belts may be conveyed toward the driven wheels by the crawler belts, adhere to the outer peripheries of the driven wheels and accumulate thereon. This phenomenon is conspicuous when the snow is fresh and powdery.  
           [0006]    Snow accumulated on the outer peripheries of the driven wheels increases the apparent outer diameter of the driven wheels, increasing the tension of the crawler belts. Propelling the snow removal machine by the crawler belts under the increased tension shortens the lives of the belts. In order to maintain a normal stretch of the crawler belts, it is necessary to remove snow accumulated on the outer peripheries of the driven wheels manually. This deteriorates efficiency in snow removing operation.  
           [0007]    It is further conceived that different amounts of snow may adhere to the right and left drive wheels and driven wheels. For example, if more snow accumulates on the left drive wheel or driven wheel, the outer diameter of the left drive wheel or driven wheel increases in appearance, whereby the snow removal machine is gradually turned to the right, losing straight advance.  
         SUMMARY OF THE INVENTION  
         [0008]    It is therefore an object of the present invention to provide a snow removing machine which is designed to effectively remove snow adhered to and accumulated on an outer periphery of a drive wheel or driven wheel.  
           [0009]    According to an aspect of the present invention, there is provided a snow removal machine comprising a body, a drive wheel and a driven wheel mounted to the body, a crawler belt wound around the drive wheel and driven wheel, and a scraper opposed to the outer periphery of the driven wheel to remove snow accumulated on the outer periphery.  
           [0010]    With the scraper, snow adhered to and accumulated on the outer periphery of the driven wheel can be removed to prevent increase in tension of the crawler belt due to the increased diameter in appearance of the driven wheel that might otherwise be caused by snow accumulating on the outer periphery. This prolongs the life of the crawler belt substantially. Removal of snow with the scraper eliminates the need for manual snow removal, thereby improving workability. No difference arises in the amounts of snow adhering to the right and left driven wheels, thereby ensuring linear travel of the snow removal machine.  
           [0011]    It is preferred that the scraper comprise blades at upper and lower ends of a surface thereof confronting the outer periphery, and a concave part at the middle part to distance the middle part from the outer periphery so as to prevent snow left on the outer periphery from making contact with the concave part, thereby preventing breakage of the scraper.  
           [0012]    In a preferred form, the scraper is bent at a substantially right angle to have a substantially L shape section, and has a mounting plate to be mounted to a lower cover provided on axes of the drive wheel and driven wheel, and a scraping member confronting the outer periphery of the driven wheel. The scraping member has a curved shape with a radius of curvature smaller than a radius of curvature of the outer periphery of the driven wheel, to form the concave part.  
           [0013]    It is preferred to integrally form a reinforcing member protruding from the middle part of a bend between the mounting plate and scraping member so as to prevent the scraping member from deforming from the bend under snow scraping load. Further, the integral molding of the reinforcing member can reduce the number of parts.  
           [0014]    The scraper is adjustable to be made close to or distanced from the outer periphery of the driven wheel and can be arranged in a preferred position relative to the outer periphery.  
           [0015]    Another scraper opposed to the outer periphery of the drive wheel to remove snow accumulating on the outer periphery can scrape snow adhering to and accumulating on the outer periphery of the drive wheel. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]    A preferred embodiments of the present invention will be described in detail below, by way of example only, with reference to the accompanying drawings, in which:  
         [0017]    [0017]FIG. 1 is a side view of a snow removal machine according to the present invention;  
         [0018]    [0018]FIG. 2 is an enlarged side view of a running part as shown in FIG. 1;  
         [0019]    [0019]FIG. 3 is a perspective view showing a relationship between a scraper as an essential part of the present invention and a driven wheel;  
         [0020]    [0020]FIG. 4 is an enlarged view of an essential part as shown in FIG. 2;  
         [0021]    [0021]FIG. 5 is a sectional view taken along line  5 - 5  as shown in FIG. 2; and  
         [0022]    [0022]FIG. 6A and FIG. 6B show a comparative example and an operation diagram of an embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0023]    The following description is merely exemplary in nature and is in no way intended to limit the invention, its application or uses.  
         [0024]    Referring to FIG. 1, a snow removal machine  10  has a body (body frame)  11  formed in substantially L shape as viewed in side elevation. A pair of right and left drive wheels  20 ,  20  and driven wheels  22 ,  22  (shown are only the left-side ones in the forward direction of the snow removal machine) are provided on the right and left sides of the body frame  11 . Crawler belts  25 ,  25  are wound around the drive wheels  20 ,  20  and the driven wheels  22 ,  22 , respectively (shown is only the left side one in the forward direction of the snow removal machine). An electric motor  30  and a power transmission mechanism  31  for driving the drive wheels  20 ,  20  are mounted to the front part of the body frame  1 . A battery  32  is arranged rearward of the electric motor  30  and the power transmission mechanism  31 . A charger  34  and a control device  35  are arranged rearward of the battery  32 . A snow removing plate  36  for pushing out snow is provided at the front end of the body frame  11 . A height adjustment mechanism  37  for adjusting the height of the snow removing plate  36  is arranged rearward of the body frame  11 . An operating handle  38  is mounted to a rear upper part of the body frame  11 . An operation box  38   a  is mounted on an upper part of the operating handle  38 . The operating handle  38  has right and left grips  39   a ,  39   b  at the rear ends thereof.  
         [0025]    A cover  18  mounted on the body frame  11  covers the electric motor  30 , power transmission mechanism  31 , battery  32 , charger  34 , and control device  35 .  
         [0026]    The battery  32  is a power source for supplying electric power to the electric motor  30  and is mounted on an upper part of the body frame  11  via a battery housing box  33 .  
         [0027]    The charger  34  charges the battery  32  with a plug (not shown) inserted into an AC power receptacle of a home power source or the like. The charger  34  is arranged rearward of the battery housing box  33  and mounted on the body frame  11 .  
         [0028]    The control device  35  controls the electric motor  30  based on signals from a forward/backward switch and a potentiometer (not shown) mounted on an upper part of the operating handle  38 , a main switch  38   b  of the operation box  38   a , and a maximum speed setting switch  38   c . The control device  35  is arranged above the charger  34  and mounted to the body frame  11 .  
         [0029]    The snow removing plate  36  is attached to a mounting bracket  36   a  mounted to the front of the body frame  11  via pins  36   b ,  36   b.    
         [0030]    In the snow removal machine  10 , the electric motor  30  is driven to transmit drive power of the electric motor  30  to the right and left drive wheels  20 ,  20  via the power transmission mechanism  31 , to rotate the right and left drive wheels  20 ,  20 , thereby to rotate the crawler belts  25  for self propelling.  
         [0031]    The operator holds the right and left grips  39   a ,  39   b  of the operating handle  38 , walking at a speed proportionate to that of the running snow removal machine  10 , to control the forward direction or the height of the snow removing plate  36  with the operating handle  38 .  
         [0032]    Referring to FIGS. 2 and 3, a lower cover  40  in a substantially elliptic shape serving as a running frame is arranged on the inner side of the drive wheel  20  and driven wheel  22 , that is on the side of the body frame  11  (See FIG. 1). The lower cover  40  has a recess  41  formed in the middle part. On the inner side of the concave part  41  welding nuts  42  are attached, into which nuts  42 , bolts  47 ,  47  are screwed to mount a scraper  45  to the lower cover  40 . At that time, a front end  50   a  of a scraping member  50  constituting the scraper  45  is made to face the outer periphery of the driven wheel  22 .  
         [0033]    A front part  40   a  of the lower cover  40  has a hole  43  through which a drive shaft  21  is inserted to mount the front part  40   a  to the drive shaft  21  via bearings  21   a . A rear part  40   b  of the lower cover  40  is mounted to a cross member  13  via a bracket  12 . Specifically, an adjustment bolt  15  is inserted through a driven shaft  23 , the bracket  12  and the cross member  13 , and a nut  16  is fastened to the adjustment bolt for mounting.  
         [0034]    Below the scraper  45 , a member  29  for preventing the lifting of the crawler belt  25  is mounted via bolts  28 ,  28 .  
         [0035]    Now the reason why the scraper  45  is made to face the outer periphery  22   a  of the driven wheel  22  will be described.  
         [0036]    When snow removing is performed with the snow removal machine  10  as shown in FIG. 1, snow is removed by the snow removing plate  36  while the machine  10  is advanced. At that time, the drive wheel  20  is driven to rotate the crawler belt  25  that is engaged with a plurality of drive pins  20   a  provided on the drive wheel  20 .  
         [0037]    The range L of contact of the crawler belt  25  with a road surface  62  is shifted in the direction of an arrow {circle over (1)}. When snow gets into the inner periphery  26  of the crawler belt  25  within the range L, the snow is conveyed on the inner periphery  26  of the crawler belt  25  to the driven wheel  22  side and adheres to the outer periphery  22   a  of the driven wheel  22 .  
         [0038]    Referring to FIG. 4, the scraper  45  consists of a mounting plate  46 , scraping member  50  and reinforcing member  57 . The scraper  45  is bent in substantially L shape to form a right angle between the mounting plate  46  mounted to the lower cover  40  and the scraping member  50  opposed to the outer periphery  22   a  of the driven wheel  22 , and has the reinforcing member  57  protruding at the middle part of a bend  55 .  
         [0039]    The mounting plate  46  has a pair of upper and lower elongated holes  48 ,  48  for adjusting the position of the scraper  45 . The mounting plate  46  is mounted to a wall constituting the recess  41  of the lower cover  40  through the elongated holes  48 ,  48 , fastened with the bolts  47 ,  47 . The elongated holes  48 ,  48  allow adjusting the position of the scraper  46  in the longitudinal direction of the lower cover  40  by loosening the bolts  47 ,  47 , thereby to arrange the scraper in a preferable position.  
         [0040]    The scraping member  50  faces the outer periphery  22   a  of the driven wheel  22  to remove snow accumulating on the outer periphery  22   a  of the driven wheel  22 . The scraping member  50  is exemplarily formed in a curved shape with a radius of curvature smaller than that of the driven wheel. A surface  51  opposed to the outer periphery  22   a  of the driven wheel  22  is resultantly in a curved shape. Both ends of the surface  51  (upper and lower ends) constitute blades  52 ,  53 . The middle part of the surface  51  constitutes a concave part  54  to be spaced from the outer periphery  22   a  of the driven wheel  22 .  
         [0041]    The reinforcing member  57  serves to prevent the scraping member  50  from deforming from the bend  55  when removing snow accumulating on the outer periphery  22   a  of the driven wheel  22 . The reinforcing member  57  is integrally molded with the mounting plate  46  and scraping member  50 , which reduces the number of parts, facilitating the assembly.  
         [0042]    Referring to FIG. 5, it is required to make the scraper  45  closer at the upper and lower blades  52 ,  53  to the outer periphery  22   a  of the driven wheel  22  so as to efficiently remove snow accumulating on the outer periphery  22   a  of the driven wheel  22 . Thus it is preferred to set space L 1  between the upper and lower blades  52 ,  53  and the outer periphery  22   a  of the driven wheel  22  as small as possible.  
         [0043]    On the other hand, it is required to distance the scraper  45  at the concave part  54  from the outer periphery  22   a  of the driven wheel  22  so as to prevent the concave part  54  from making contact with snow left on the outer periphery  22   a  of the driven wheel  22 . Thus it is preferred to set space L 2  between the concave part  54  and the outer periphery  22   a  of the driven wheel  22  larger.  
         [0044]    Now the function of the snow removal machine  10  according to the present invention will be described by comparing the comparative example as shown in FIG. 6A with the present embodiment as shown in FIG. 6B.  
         [0045]    In FIG. 6A, to advance the snow removal machine, a drive wheel  100  is rotated in the direction of an arrow {circle over (2)} to rotate a crawler belt  101  in the direction an arrow {circle over (3)} and to rotate a driven wheel  103  in the direction of an arrow {circle over (4)}.  
         [0046]    Snow  105  getting into the inner periphery  102  of the crawler belt  101  is conveyed to the direction of the driven wheel  103 , being on the inner periphery  102  of the crawler belt  101 . The snow  105  conveyed adheres to and accumulates on the outer periphery  103   a  of the driven wheel  103 .  
         [0047]    The snow  105  accumulating on the outer periphery  103   a  of the driven wheel  103  increases in appearance the outer diameter Dl of the driven wheel  103  to stretch the crawler belt. Running in this state may shorten the life of the crawler belt  101 . To maintain a normal stretch of the crawler belt  101 , it is necessary to remove the snow  105  accumulating on the outer periphery  103   a  of the driven wheel  103  on a frequent basis, preventing improving snow removing workability. It is further conceivable that different amounts of snow  105  adhere to the right and left drive wheels  100  or driven wheels  103  (only left-side ones are shown). For example, if more snow  105  accumulates on the left drive wheel  100  or driven wheel  103 , the snow removal machine will gradually turn to the right. This adversely affects the straight advancement of the snow removal machine, and requires compensating the adverse affect by operating the operating handle, increasing load of the operator.  
         [0048]    In FIG. 6B, in advancing the snow removal machine of this embodiment, if snow  60  gets into the inner periphery  26  of the crawler belt  25 , the snow  60  is conveyed in the direction of the driven wheel  22  as shown in an arrow, being on the inner periphery  26  of the crawler belt  25 . The snow  60  conveyed adheres to and accumulates on the outer periphery  22   a  of the driven wheel  22 .  
         [0049]    In this embodiment, however, the scraping member  50  of the scraper  45  is opposed to the outer periphery  22   a  of the driven wheel  22 , so that the snow  60  accumulating on the outer periphery  22   a  of the driven wheel  22  is removed by the upper blade  52  of the scraping member  50 . Thus, the accumulation of the snow  60  on the outer periphery  22   a  of the driven wheel  22  is avoided to prevent the crawler belt  25  from increasing its tension. Thus it is possible to use the crawler belt  25  in a normal state, which ensures sufficiently long life of the crawler belt  25 . No further operation to remove the snow  60  accumulating on the outer periphery  22   a  of the driven wheel  22  is required, which increases workability in removing snow.  
         [0050]    In setting the snow remove machine backward, the drive wheel  20 , crawler belt  25 , and driven wheel  22  are rotated in the opposite direction to the rotational direction in advancement. At that time, the lower blade  53  of the scraper  45  removes the snow  60  accumulating on the outer periphery  22   a  of the driven wheel  22 .  
         [0051]    The above embodiment shows an example in which the scraper  45  faces the driven wheel  22 . It is also possible to provide another scraper  45  facing the drive wheel  20 .  
         [0052]    Further, the above embodiment shows an example in which the scraper  45  has the scraping member  50  formed in a substantially curved shape. It is also possible to make it in another shape. The point is that the blades  52  and  53  be closer to the outer periphery  22   a  of the driven wheel  22  and the concave part  54  distanced from the outer periphery  22   a . For example, a rectangular C shape is applicable. It is also possible to make the scraping member  50  have only the upper blade  52 .  
         [0053]    In the above-described embodiment, the snow removal machine  10  has the snow removing plate  36 . It is also possible to apply the present invention to a snow removal machine having another snow removing means such as a rotary snow removing device, to provide similar effects.  
         [0054]    Obviously, various minor changes and modifications of the present invention are possible in the light of the above teaching. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

Summary:
A snow removal machine propelled by crawler belts trained around drive wheels and driven wheels is provided. The snow removal machine has a scraper confronting the outer periphery of the driven wheel so as to remove snow adhering to and accumulating on the outer periphery during snow removing operation. It prevents increase in tens ion of the crawler belt due to the increased diameter of the driven wheel in appearance that might otherwise be caused by snow adhering to the outer periphery.