Patent Publication Number: US-8113294-B2

Title: Beach cleaner

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application claims priority under 35 U.S.C. §119 to Japanese Patent Application No. 2006-101616, filed Apr. 3, 2006, the entire contents of which are hereby incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a beach cleaner which collects various waste scattered on a sand area such as a bathing beach. 
     2. Description of Background Art 
     Examples of such an existing beach cleaner described above include a beach cleaner as below. The beach cleaner includes a plurality of longitudinal members extending in the traveling direction are spaced at desired intervals apart from each other to form a floor grate-like frame. The longitudinal members are provided with a plurality of sand pins projecting downward. While the sand pins are buried in a sand area, the beach cleaner is towed by a towing vehicle to run on the sand area, thereby enabling collecting relatively large waste. (See Japanese Patent No. 3623435.) 
     Incidentally, the beach cleaner described above may result in an excessive increase in traveling resistance because the sand pins are buried too far into a soft sand area. On the other hand, in a hard sand area, the cleaner may be susceptible to almost floating because the sand pins are not sufficiently buried into the sand. As a result, the waste collection performance of the beach cleaner may be adversely affected. 
     SUMMARY AND OBJECTS OF THE INVENTION 
     Accordingly, it is an object of the present invention to enhance the waste collection performance of a beach cleaner provided with a plurality of sand pins projecting downward from a floor grate-like frame by optimizing an amount of burying the sand pins in a sand area. 
     According to a first aspect of the present invention, a beach cleaner (e.g. the first beach cleaner  20 ,  120 ,  220  of the embodiment) includes a plurality of longitudinal members (the longitudinal members  21  of the embodiment) extending in a traveling direction are spaced widthwise apart from each other to form a floor grate-like frame (e.g. the frame  22  of the embodiment). The longitudinal members are provided with a plurality of sand pins (e.g. the san pins  23  of the embodiment) projecting downward therefrom, and the frame is provided at a front end thereof with a tow portion (e.g. the tow portion  37  of the embodiment). The beach cleaner is pulled by a towing vehicle (e.g. the tow vehicle  1  of the embodiment) to run on a sand area, while the sand pins scrape and collect waste scattered on the sand. The sand pins are detachably attached to the longitudinal members. 
     According to a second aspect of the present invention, the frame is provided with a weight mount portion (e.g. the weight mount portion  31  of the embodiment). 
     According to a third aspect of the present invention, a waste collecting portion (e.g. the waste collecting portion  21   a  of the embodiment) is provided between the sand pins aligned in the back and forth direction in the frame. 
     According to a fourth aspect of the present invention, a joint portion (e.g. the joint portion  22   a  of the embodiment) is provided between the sand pins aligned in the back and forth direction in the frame. 
     EFFECTS OF THE INVENTION 
     According to the first aspect of the present invention, the number of the sand pins can be increased and reduced. The number of the sand pins is reduced when the sand area has large resistance and the number of the sand pins is increased when the sand area has small resistance. Thus, the amount of burying the sand pins in the sand area is optimized to enhance waste collection performance. 
     According to the second aspect of the present invention, the amount of burying the sand pins in the sand area can be also adjustable by the heft of the weight, thereby further enhancing the waste collection performance. 
     According to the third aspect of the present invention, floating of the frame and the sand pins because of riding on the waste collected by the sand pins is prevented, whereby the waste collection performance can be satisfactorily maintained. 
     According to the fourth aspect of the present invention, floating of the frame and the sand pins because of riding on the waste collected by the sand pins is prevented, whereby the waste collection performance can be satisfactorily maintained. 
     Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein: 
         FIG. 1  illustrates a state where beach cleaners and the like according to an embodiment of the invention loaded on a trailer are carried. 
         FIG. 2  is a side view of a first beach cleaner of the embodiment; 
         FIG. 3  is a plan view of  FIG. 2 ; 
         FIGS. 4(   a ) and ( b ) include explanatory views of a sand pin of the first beach cleaner, in which  FIG. 4(   a ) is a side view and  FIG. 4(   b ) is a view as viewed from arrow A of  FIG. 4(   a ); 
         FIGS. 5(   a ) and ( b ) include explanatory views of a modified example of the sand pin, in which  FIG. 5(   a ) is a side view and  FIG. 5(   b ) is a view as viewed from arrow A of  FIG. 5(   a ); 
         FIG. 6  is a side view illustrating a weight mount portion attached to the first beach cleaner; 
         FIG. 7  is a plan view of  FIG. 6 ; 
         FIGS. 8(   a ) and ( b ) include explanatory views of the weight mount portion of  FIG. 6 , in which  FIG. 8(   a ) is a plan view and  FIG. 8(   b ) is a side view; 
         FIG. 9  is an exploded explanatory view of the weight mount portion of  FIG. 6  and a weight attached thereto; 
         FIG. 10  is a side view of the weight mount portion attached to a front carrier of the towing vehicle; 
         FIG. 11  is a plan view of  FIG. 10 ; 
         FIG. 12  is an exploded explanatory view of the weight mount portion of  FIG. 10  and a weight attached thereto; 
         FIG. 13  is a side view of a waste recovery station according to the embodiment; 
         FIG. 14  is a plan view of  FIG. 13 ; 
         FIG. 15  is a perspective view for assistance in explaining the dividing structure portion of the waste recovery station; 
         FIG. 16  is a side view of a second beach cleaner according to the embodiment; 
         FIG. 17  is a plan view of  FIG. 16 ; 
         FIG. 18  is a rear view of  FIG. 16 ; 
         FIG. 19  is a side view of the front portion of the frame of the second beach cleaner; 
         FIG. 20  is a view as viewed from arrow A of  FIG. 19 ; 
         FIG. 21  is a side view illustrating the periphery of hinges for a net of the second beach cleaner; 
         FIG. 22(   a ) is a view as viewed from arrow A of  FIG. 21 , and  FIG. 22(   b ) is a view as viewed from arrow B of  FIG. 21 ; 
         FIGS. 23(   a ) and ( b ) illustrate an example where the net of the second beach cleaner is made movable forwardly and backwardly, in which  FIG. 23(   a ) is a side view of the net located at its withdrawal position, and  FIG. 23(   b ) is a side view of the net located at its forward position; 
         FIG. 24  is an explanatory diagram illustrating the running trajectory of a vehicle when the beach cleaners of the embodiment clean a sandy beach; 
         FIG. 25  is a side view illustrating a state where the first beach cleaner is towed by the vehicle; 
         FIG. 26  is a side view illustrating a state where the second beach cleaner is towed by the vehicle; 
         FIG. 27  is a side view of a modified example of the first beach cleaner described above; and 
         FIG. 28  is a side view of a second modified example of the first beach cleaner described above. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A vehicle  1  depicted in  FIG. 1  is configured as a so-called ATV (All Terrain Vehicle). The vehicle  1  includes left and right front wheels  2  and rear wheels  3  disposed at the front portion and rear portion, respectively, of a vehicle body formed small in size and light in weight. The wheels are low pressure balloon tires with a relatively large diameter. Thus, the vehicle  1  ensures a large minimum ground height, thereby enhancing traveling performance on, particularly, the irregular terrain. A body frame  4  of the vehicle body  1  is formed at the widthwise central portion to have a box structure long in the back and forth direction. An engine  5  as a prime mover for the vehicle  1  is mounted on the almost central portion of the body frame  4 . 
     The engine  5  is a water-cooled single cylinder engine for example. The rotational power of a crankshaft is output to front and rear propeller shafts  6   a  and  6   b  via a gear-meshing type transmission. The rotational power output to the front and rear propeller shafts  6   a  and  6   b  are output to left and right front and rear wheels  2  and  3  via front and rear reduction gears  7   a  and  7   b , respectively. 
     The vehicle  1  is a so-called semi-automatic vehicle which is able to electrically change the gear ratio of the transmission. The gear ratio can be changed through, for example, a centrifugal clutch, by operating only a change button or the like without operating the clutch. Such a vehicle  1  is suitable for running with a large running load or at constant speed as compared with a vehicle equipped with a belt type transmission. 
     The left and right front wheels  2  are suspended by the front portion of the body frame  4  through front independent suspensions  8   a . The left and right rear wheels  3  are suspended by the rear portion of the body frame  4  through e.g. swing arm type rear suspensions  8   b . Trailer hitches  11  for towing a trailer are provided at the rear ends of swing arms  9  of the rear suspensions  8   b . In the figure, reference numeral  12   a  denotes a front carrier supported by the front portion of the body frame  4  and  12   b  denotes a rear carrier supported by the rear portion of the body frame  4 . 
     The vehicle  1  can tow a trailer  13  which carries a first and a second beach cleaner  20 ,  50  and a waste recovery station  40 . 
     The trailer  13  includes a pair of left and right wheels  15 , a carrier  16  and a tow-arm  17 . The wheels  15  are provided on both sides of the lower portion of a body frame  14  of the trailer  13  for instance. The carrier  16  is in a shallow box shape opening upward and is provided on the body frame  14 . The tow-arm  17  extends from the lower side of the front portion of the body frame  14  toward the forward. A hitch coupler  17   a  associated with the trailer hitch  11  is provided at the front end of the tow-arm  17 . 
     Receiving members  16   a  adapted to support connecting pipes  46 , described later, of a waste recovery station  40  are provided at upper edge portions, of a carrier  16 , located on front and rear, left and right sides thereof. The receiving member  16   a  is formed with a V-shaped recess opening upward. The connecting pipe  46  is supportably received in the recess with the wasted recovery station  40  in the loaded state turned upside down. A second beach cleaner  50  is loaded on the waste recovery station  40  in the loaded state, while being engaged with, e.g. grounded members  43  described later so as to be restricted in movement. In addition, a first beach cleaner  20  is loaded on the waste recovery station  40  in the loaded state, while being received, e.g. in the carrier  16 . 
       FIG. 1  illustrates a state in which the beach cleaners  20 ,  50  and the waste recovery station  40  are loaded on the trailer  13 .  FIG. 2  and the subsequent figures illustrate a state in which the beach cleaners  20 ,  50  and the waste recovery station  40  are used on a sand area, unless otherwise specified. In the figures, line GL denotes the ground (the upper surface of the sand area) and line CL denotes the respective widthwise centers of the vehicle  1 , the beach cleaners  20 ,  50  towed by the vehicle  1  and the waste recovery station  40  through which the beach cleaners  20 ,  50  pass. (The vehicle  1 , the beach cleaners  20 ,  50  and the waste recovery station  40  are hereinafter called the vehicle and the like.) Arrow FR denotes the forward in the running direction (the back and forth direction) of the vehicle or the like. Arrow UP denotes the upside in the upward and downward direction of the vehicle and the like. Arrow LH denotes the left in the leftward and rightward direction in the vehicle and the like. 
     While running on a sand area (a sandy beach) of a sea shore, the beach cleaners  20 ,  50  collect various waste scattered on the sand area. The waste collected by the beach cleaners  20 ,  50  is collectively recovered by the waste recovery station  40  installed on the desired site on the sand area. The beach cleaners  20 ,  50  and the waste recovery station  40  are appropriately assembled by a plurality of kinds of steel materials such as stainless steel using joining means such as welding. Incidentally, the beach cleaners  20 ,  50  may be towed by a tractor. 
     Referring to  FIGS. 2 and 3 , the first beach cleaner  20  includes a plurality of (e.g. 15) longitudinal members  21  which extend in the running direction and are placed so as to be almost evenly spaced apart from each other in the widthwise direction (the leftward and rightward direction), thereby forming a floor grates-like frame  22 . In addition, a plurality of sand pins  23  are detachably attached to the respective longitudinal members  21  so as to project downward. Incidentally, the first beach cleaner  20  is configured to be symmetrical. 
     The longitudinal member  21  is made of e.g. a circular steel tube (or rectangular steel tube). The longitudinal member  21  extends along the back and forth direction and has front and rear end portions which bend upwardly forwardly and upwardly rearward, respectively. A plurality of the longitudinal members  21  are juxtaposed to each other right and left so as to be superposed as viewed from the side. The longitudinal member  21  is connected at its front end to a front lateral member  24   a  so as to be abutted against it from obliquely and downward-rearward. The front lateral member  24   a  is made of e.g. a rectangular steel tube and extends in the leftward and rightward direction. In addition, the longitudinal member  21  is connected at its rear end to a rear lateral member  24   b  so as to be abutted against it from obliquely and downward-forwardly. The rear lateral member  24   b  is made of e.g. a rectangular steel tube and extends in the leftward and rightward direction. 
     The frame  22  composed of the longitudinal members  21  and the lateral members  24   a ,  24   b  is formed in a horizontally long rectangle as viewed from above. The left-right width of the frame  22  is made equal to or slightly greater than that of the vehicle  1  and smaller than that between left and right side structures  41  of the waste recovery station  40  described later. 
     The sand pins  23  can be attached to the front portion, intermediate portion and rear portion of each longitudinal member  21 . In other words, the sand pins  23  are arranged in three rows in the back and forth direction. This makes it possible to suppress travel resistance during low-speed travel and to further suppress travel resistance by reducing the number of the sand pins  23  according to the hardness of the sand area or the like. The length of the sand pin  23  that project from the lower surface of the frame  22  is set to 100 mm at most in order to suppress an effect on the ecological system in the sand area. 
     While the first beach cleaner  20  as described above travels on the sand area, relatively large waste (ropes, nets, driftwood, etc.) scattered is caught or tangled with and thus raked up by the sand pins  23 . 
     Additionally referring to  FIG. 4 , the sand pin  23  includes a plate-like member  25 , a pin main body  26  and a support member  27 . The plate-like member  25  bends to conform to the lower outer surface of the longitudinal member  21 . The pin main body  26  vertically passes through the plate-like member  25 . The support member  27  bridges over the lower portion of the pin main body  26  and the rear portion of the plate-like member  25 . The support member  27  is formed to be in a triangle, as viewed from the side, tapered toward the downside. The pin main body  26  is formed at its upper portion with an external thread portion  26   a . While this external thread portion  26   a  passes through the longitudinal member  21  from below and projects upward therefrom, the plate-like member  25  is abutted against the lower surface of the longitudinal member  21 . In this state, a hexagon cap nut  28  is threaded and fastened onto the external thread portion  26   a , whereby the sand pin  23  is fastened to the longitudinal member  21 . A cylindrical collar  29  is fixedly inserted through a portion of the longitudinal member  21  through which the pin main body  26  passes. 
     As shown in  FIG. 5 , if a longitudinal member  21 ′ is made of a rectangular steel tube, a sand pin  23 ′ designed to accommodate to the longitudinal member  21 ′ may be used. Specifically, the sand pin  23 ′ includes a plate-like member  25 ′ which is U-shaped in section so as to conform to the lower outer surface of the longitudinal member  21 ′. In the state where the plate-like member  25 ′ conforms to the lower portion of the longitudinal member  21 , a hexagon cap nut  28  is threaded and fastened onto the external thread portion  26   a , whereby the sand pin  23 ′ is fastened to the longitudinal member  21 ′. The longitudinal member  21 ′ has a relatively broad left-right width in section. Use of such a longitudinal member  21 ′ enhances glide performance of the first beach cleaner  20  relative to a sand area. If the lower end of the pin main body  26  is made to bend forward to form a folding back part  26   b , waste recovery performance can be further enhanced. 
     Referring to  FIGS. 6 and 7 , a weight mount portion  31  adapted to adjust an amount of digging the sand pins  23  in the sand can be installed on the frame  22  of the first beach cleaner  20 . 
     Additionally referring to  FIG. 8 , the weight mount portion  31  is configured by integrally connecting base parts  32  juxtaposed right and left using a support bracket  33 . The base parts  32  are longitudinally long, that is, extend in the back and forth direction and are arranged to have the same left-right width as that of the adjacent longitudinal members  21  of the frame  22 . Each base part  32  is formed at its front and rear edges with insertion holes  32   a  adapted to receive the external thread portions  26   a  of the sand pins  23  insertable therethrough. The sand pins  23  are attached to the frame  22  so as to be arranged in the back and forth direction. The support bracket  33  is provided to be mounted on the front-rear intermediate portions of the base parts  32 . The support bracket  33  is formed in a U-shape in section opening rearward so as to extend right and left. 
     The weight mount portion  31  as described above can be attached to a portion of the frame  22  attached with the sand pins  23  by being co-fastened with the sand pins  23 . In addition, the weight mount portion  31  can be attached to a portion of the frame  22  attached with no sand pin  23  by means of an associated bolt or the like. In short, the arbitrary number of the weight mount portions  31  can be installed at arbitrary places on the frame  22 . 
     Additionally referring to  FIG. 9 , a weight  34  is configured to be dividable into a lower block  34   a  fitted to the support bracket  33  from the rearward and an upper block  34   b  fitted to the lower block  34   a  from above. 
     The lower block  34   a  is fixedly connected to the support bracket  33  by a retaining pin  35   a  passing up and down through the lower bracket  34   a  and the support bracket  33  with the front end portion of the lower block  34   a  fitted into the support bracket  33 . The upper block  34   b  is fixedly connected to the lower block  34   a  by a connecting bolt  35  passing up and down through the upper block  34   b  and the lower block  34   a  with the lower portion of the upper block  34   b  conforming to the upper portion of the lower block  34   a.    
     Referring to  FIGS. 10 ,  11 , a desired weight mount portion  31 ′ can be installed on the front carrier  12   a  of the vehicle  1  in order to ensure a load applied the front wheels for satisfactory driving force even if travel resistance is increased because of the weight  34  mounted on the first beach cleaner  20 . 
     The weight mount portion  31 ′ is integrally configured to include a base part  32 ′ extending along the upper surface of the front carrier  12   a  and a support bracket  33 , similar to that of the weight mount portion  31 . The base part  32 ′ is formed like a plate rectangular as viewed from the above and is detachably attached to pipe members at its front and rear lower surfaces. The pipe members extend in the leftward and rightward direction so as to constitute the front carrier  12   a.    
     Additionally referring to  FIG. 12 , the weight  34 ′ supported by the weight mount portion  31 ′ is configured to be dividable into a lower block  34   a ′ fitted into the support bracket  33  from the rearward and the upper block  34   b  fitted into the lower block  34   a ′ from above. 
     The lower block  34   a ′ has a slightly increased amount of rearward extension as compared with the lower block  34   a . The front end portion of the lower block  34   a ′ is fixedly connected to the support bracket  33  with the retaining pin  35   a . While the lower portion of the upper block  34   b  conforms to the upper rear portion of the lower block  34   a ′, the upper and lower blocks  34   a ′,  34   b  are fixedly connected to each other with the connecting bolt  35   b . The weight  34 ′ is set in weight to a level greater than the weight  34 . When the wheels spin free with respect to the sand, tire chains may be attached to the wheels. 
     With reference to  FIGS. 2 and 3 , a tow portion  37  used to by the vehicle  1  to pull the first beach cleaner  20  is provided in front of e.g. a third longitudinal member  21  from each of the left and right outside ends of the frame  22 . The tow portion  37  is made of a thick plate extending perpendicular to the leftward and rightward direction and is formed with a plurality of (e.g. three) connecting holes  37   a  so as to be aligned along the inclination of the front end of the longitudinal member  21 . One end of the tow rod  38  is connected to any one of the connecting holes  37   a ; the other end of the tow rod  38  is connected to the trailer hitch  11  of the vehicle  1 . Thus the first beach cleaner  20  is towed by the vehicle  1  via the tow rod  38  (see  FIG. 25 ). 
     In this case, the optimum towing position according to the digging of the first beach cleaner  20  into the sand can be set by connecting the one end of the tow rod  38  to which one of the connecting holes  37   a . Additionally referring to  FIG. 14 , the tow rod  38  extends from the one end side coupled to the trailer hitch  11  toward the left and right tow portions  37  so as to be V- or Y-shaped as viewed from above. The hitch coupler  17   a  associated with the trailer hitch  11  is provided at the one end side. 
     Lift arms  39  are provided on the left and right outside of the frame  22  so as to protrude leftward and rightward, respectively, from the outside end of the frame  22 . The lift arm  39  is formed like a horizontally long rectangular frame, for instance, as viewed from above. In the lift arm, the left-right intermediate portion is formed almost horizontally, the left-right inside portion is formed to bend obliquely downward and inward, and the left-right outside portion is formed to bend obliquely downward and outwardly. The left-right width between the outside ends of the left and right lift arms  39  is greater than the left-right width of the left and right side structures  41  of the waste recovery station  40 . When the first beach cleaner  20  towed by the vehicle  1  enters between the left and right side structures  41 , the left and right lift arms  39  ride on the left and right side structures  41 , respectively, whereby the first beach cleaner  20  is lifted up at a desired amount. Incidentally, the distance between the left and right side structures  41  is greater than the left-right width of the vehicle  1 , so that the vehicle  1  can pass between the left and right side structures  41 . 
     Referring to  FIGS. 13 and 14 , when the first beach cleaner  20  is lift up on the waste recovery station  40 , the sand pins  23  are sufficiently spaced apart from the upper surface of the sand area and the waste raked up by the sand pins  23  can be allowed to drop. Thus, the waste can be collectively recovered. 
     The waste recovery station  40  is configured by integrally connecting the left and right side structures  41  with a pair of front and rear connecting members  42 . The waste recovery station  40  is configured to be symmetrical with respect to the front and rear thereof and to the left and right thereof for instance. 
     The left and right side structures  41  are each formed such that a guide member  44  is attached on a bar-like grounded member  43  and the front and rear ends of both the members  43 ,  44  are integrally coupled to each other. The guide member  44  is made of e.g. a circular steel tube and formed like a gentle mountain which is symmetrical with respect to the front and rear thereof as viewed from the side. The grounded member  43  is made of e.g. a circular steel tube and extends in the back and forth direction. 
     Foot members  45  are detachably attached to the front and rear ends of each of the left and right grounded members  45  so as to bend so that they are located further leftward or rightward outward as going forward or rearward as viewed from above. The foot members  45  are placed on the sand area together with the grounded members  43 , whereby the waste recovery station  40  is stably installed while increasing its installation area. 
     Additionally referring to  FIG. 15 , the connecting member  42  is made of e.g. a circular steel tube and extends in the leftward and rightward direction. An end of the connecting member  42  is detachably inserted into a connection pipe  46  disposed under each of the front or rear portions of the grounded member  43 . In this state, the left and right side structures  41  are integrally connected to each other. In other words, since the waste recovery station  40  has a relatively large size, it is made dividable into a plurality of divided bodies (the left and right side bodies  41  and the front and rear connecting members  42 ). 
     The connecting pipe  46  associated with the grounded member  43  is made of a relatively short circular steel tube and extends in the leftward and rightward direction. The connecting pipe  46  is integrally connected to the grounded member  43  in such a manner that its upper external circumference conforms to the lower notch of the grounded member  43 . In other words, the connecting pipe  46  projects downwardly from the lower surface of the grounded member  43 . When the waste recovery station  40  is installed on the sand area, the connecting pipes  46  dig into sand to suppress movement of the waste recovery station  40 . 
     An end of the connecting member  42  is inserted into the connecting pipe  46  at a predetermined amount, thereby providing an assembled state (for example, a state where the outer edge of the connecting pipe  46  is made to coincide with the outer edge of the connecting member  42 ). In this state, upper and lower through-holes  46   a  formed in the connecting pipe  46  are respectively superposed on upper and lower through-holes  42   a  formed in the connecting member  42  at positions on the leftward and rightward oust side of the grounded member  43  for example. A desired retaining pin  47  is inserted into the upper and lower through-holes  42   a ,  46   a  to unremovably connect the connecting member  42  with the grounded member  43  in the assembled state. 
     The retaining pin  47  passes through the connecting member  42  and the connecting pipe  46 , further projecting downwardly, and is dug into sand at a desired amount. Thus, the retaining pins  47  suppress movement of the waste recovery station  40  from the predetermined installation site. If the retaining pins  47  are removed and the connecting members  42  are detached from the connecting pipes  46 , the waste recovery station  40  can be divided into the left and right side structures  41  and the front and rear connecting members  42 . 
     Referring to  FIGS. 16 and 17 , the second beach cleaner  50  mainly includes a plurality of (e.g. three) longitudinal members  51  extending in the traveling direction of the vehicle; and front and rear lateral members  52   a ,  52   b  extending in the widthwise direction (the leftward and rightward direction) so as to be perpendicular to the longitudinal members  51 . The longitudinal members  51  and the lateral members  52   a ,  52   b  form a frame  53 . The frame  53  is provided at its front portion with keels  54  and scrapers  55  described later and at its rear portion with a net  56  described later. The second beach cleaner  50  is also configured to be symmetrical. 
     The longitudinal member  51  is made of e.g. a circular steel tube and extends in the back and forth direction. The longitudinal member  51  is moderately cranked at its intermediate portion as viewed from the side so that its rear portion is shifted slightly upward from the front portion thereof. A central portion of the front portion of the longitudinal member  51  moderately bends so that a front half portion of the front portion is provided to slant forwardly and slightly upwardly. The front half portion of the front portion of the longitudinal member  51  is hereinafter referred to as the front slant portion  57 . On the other hand, the rear end of the longitudinal member  51  is provided to bend upwardly. The longitudinal member  51  may be made of a rectangle steel tube. 
     A plurality of the longitudinal members  51  are juxtaposed left and right so as to be superposed as viewed from the side. The longitudinal member  51  is abutted at its front end against the front lateral member  52   a  from the rearward for connection therewith. The front lateral member  52   a  is made of e.g. a rectangular steel tube and extends in the leftward and rightward direction. In addition, the longitudinal member  51  is abutted its rear end against the rear lateral member  52   b  from below for connection therewith. The rear lateral member  52   b  is made of e.g. a circular steep tube and extends in the leftward and rightward direction. The frame  53  mainly including the longitudinal members  51  and the lateral members  52   a ,  52   b  is formed in an almost-square as viewed from above. Incidentally, the frame  53  has a left-right width approximately equal to that of the frame  22  of the first beach cleaner  20 . 
     A plurality of (e.g. three) scraper frames  58  are juxtaposed left and right between a central longitudinal member  51  and each of left-end and right-end longitudinal members  51  so as to be superposed on the front slant portions  57  as viewed from the side. The scraper frame  58  is made of a circular steel tube (which may be a rectangular steel tube) having the same diameter as that of the longitudinal member  51 . The scraper frame  58  is abutted at its front end against the front lateral member  52   a  from the rearward for connection therewith. On the other hand, the rear end of the scraper frame  58  is not connected to any members, that is, serves as a free end. The scraper frames  58  and the central longitudinal member  51  are spaced equally apart from each other. The outermost left scraper frame  58  and the left longitudinal member  51 , and the outermost right scraper frame  58  and the right longitudinal member  51 , are each arranged to have narrow spacing therebetween. 
     The keels  54  and scrapers  55  are attached to the front slant portions  57  of the longitudinal members  51  and to the scraper frames  58 . The keels  54  and scrapers  55  serve as a raking-up portion which rakes up sand and relatively small waste (drink boxes, paper scraps, cigarette butts, etc.) while the second beach cleaner  50  travels, being towed. 
     Additionally referring to  FIGS. 19 and 20 , the keel  54  is detachably attached to the rear portion of the front slant portion  57  of the longitudinal member  51  and to the rear portion of the scraper frame  58 . The keel  54  includes a plate-like member  61 , a U-shaped pin  62  and a keel main body  63 . The plate-like member  61  bends to conform to the lower outer surface of the front slant portion  57  or the scraper frame  58 . The U-shaped pin  62  is formed in a U-shape opening upward and has both side portions passing through the plate-like member  61 . The keel main body  63  is formed like a plate to extend almost perpendicularly to the leftward and rightward direction and extends downward from the lower edge of the plate-like member  61 . 
     The upper parts of both side portions of the U-shaped pin  62  are formed as external thread parts  62   a . The external thread parts  62   a  pass through the front slant portion  57  or the scraper frame  58  from below to project upward therefrom. In this state, the plate-like member  61  abuts against the lower surface of the front slant portion  57  or the scraper frame  58 . In this state, a hexagon cap nut  64  is threaded on each of the external thread parts  62   a  and fastened thereto, whereby the keel  54  is fastened to the front slant portion  57  or the scraper frame  58 . A cylindrical collar  65  is fixedly inserted through a portion, of the front slant portion  57  or the scraper frame  58 , through which each of the side portions of the U-shaped pin  62  passes. 
     The keel  54  (the keel main body  63 ) is formed at its rear end with a plurality of scraper support holes  66 , by which the scrapers  55  is insertably supported. The scraper  55  is formed like a bar circular in section for instance and extends in the leftward and rightward direction. The scrapers  55  extend across the keels  54  while insertably supported by the upper and lower support holes  66 . The scrapers  55  can be selectively supported according to the conditions of the sandy beach and waste and the plurality of scrapers can be supported. To prevent the scrapers  55  from falling from the respective keels  54 , the scrapers  55  are provided at their ends with locking devices such as desired retaining pins inserted thereto. The sectional shape of the scraper  55  is not limited to a circle but may be of a semicircle with an upper surface extending forwardly downwardly. The scraper  55  may be one, three or more. In addition, the scrapers may be arranged not above and below but right and left or obliquely. 
     The keels  54  and the scrapers  55  are set so as to be dug into sand at an appropriate depth. While the second beach cleaner  50  runs in this state, the keels  54  push aside sand and waste and the scrapers  55  scrape up them. In this way, the sand and waste thus scraped up are thrown into the net  56  provided at the rear portion of the frame  53 . 
     With reference to  FIGS. 16 and 17 , a tow portion  67  is provided in front of e.g. a second scraper frame  58  from each of the left and right outside ends of the frame  53 . The tow portion  67  is used by the vehicle  1  to pull the second beach cleaner  50 . The tow portion  67  is made of a thick plate extending perpendicular to the leftward and rightward direction and is formed with a plurality of (e.g. four) connecting holes  67   a  arranged up and down. One end of the tow rod  38  is connected to any one of the connecting holes  67   a ; the other end of the tow rod  38  is connected to the trailer hitch  11  of the vehicle  1 . Thus the second beach cleaner  50  is towed by the vehicle  1  via the tow rod  38  (see  FIG. 26 ). 
     In this case, the optimum towing position according to the ground height of the second beach cleaner  50  can be set by connecting the one end of the tow rod  38  with which one of the connecting holes  67   a . The left-right distance between the left and right tow portions  67  is approximately equal to that between the left and right tow portions  37 . 
     A front ski support pipe  72  supporting a front ski leg  71  is provided, for instance, forward of each of the left and right outermost scraper frames  58  included in the frame  53 . The front ski support pipe  72  is made of e.g. a rectangular steel tube and passes through the front lateral member  52   a  vertically. The front ski support pipe  72  can supportably pass a leg member  73  of the front ski leg  71  therethrough. The leg member  73  is also made of a rectangular steel tube. The front ski leg  71  is adapted to set the ground height (the height from the upper surface of the sand area) of the front portion of the second beach cleaner  50  and to enhance glide performance relative to the sand area. The front ski leg  71  includes a front ski plate  74  with a predetermined width having a front portion bending forwardly upwardly and the leg member  73  provided on the front ski plate  74  so as to extend upright. 
     The front ski support pipe  72  is formed with left and right through-holes  72   a . The leg member  73  is formed with a plurality of (e.g. four) left and right through-holes  73   a  arranged up and down so as to correspond to the left and right through-holes  72   a . Any one of the left and right through-holes  73   a  is superposed on one of the left and right through-holes  72   a  of the front ski support pipe  72  and a predetermined retaining pin or the like is inserted into the through-holes thus superposed. This determines the height of the front portion of the frame  53  relative to the front ski leg  71 , whereby the ground height of the front portion of the second beach cleaner  50  is set at a desired level. In other words, the ground height of the front portion of the second beach cleaner  50  can be adjusted by inserting the retaining pin or the like into which one of the left and right through-holes  73   a  of the leg member  73 . Thus, the amount of digging the keels  54  and the scrapers  55  into sand can be adjusted. 
     An extension frame  75  made of e.g. a rectangular steel tube extends from a rear portion, on each of both sides, of the rear lateral member  52   b . A rear ski support pipe  77  is provided at the rear end of the extension frame  75  so as to support a rear ski leg  76 . The rear ski support pipe  77  is made of e.g. a rectangular steel tube and passes through the extension frame  75  upwardly and downwardly. The rear ski support pipe  77  can supportably pass a leg member  78  of the rear ski leg  76  therethrough. The leg member  78  is also made of a rectangular steel tube. The rear ski leg  76  has the same configuration and function as the front ski leg  71 . That is to say, the rear ski leg  76  is provided on a rear ski plate  79  so as to extend the leg member  78  upright. 
     The rear ski support pipe  77  is formed with a single left-right through-hole  77   a . The leg member  78  is formed with a plurality of (e.g. four) left-right through-holes  78   a  arranged up and down so as to correspond to the left-right through-hole  77   a . Any one of the left-right through-holes  78   a  is superposed on the left-right through-hole  77   a  of the rear ski support pipe  77  and a predetermined retaining pin or the like is inserted into the through-holes thus superposed. This determines the height of the rear portion of the frame  53  relative to the rear ski leg  76 , whereby the ground height of the rear portion of the second beach cleaner  50  is set at a desired level. (In other words, the ground height of the rear portion of the second beach cleaner  50  can be adjusted.) The left-right width between the outer ends of the front ski plates  74  of the left-right front ski legs  71  is made approximately equal to the left-right width of the frame  53 . The left-right width between the outer ends of the rear ski plates  79  of the left and right rear ski legs  76  is made smaller than the left-right width of the frame  53 . 
     Front lift arms  81   a  are provided on the left and right outside of the front portion of the frame  53  so as to protrude leftward and rightward, respectively. Rear lift arms  81   b  are provided on the left and right outside of the rear portion of the frame  53  so as to protrude leftward and rightward, respectively. The lift arms  81   a ,  81   b  are each formed like a horizontally long rectangular frame, for instance, as viewed from above. In each lift arm, the left-right intermediate portion is formed almost horizontally, the left-right inside portion is formed to bend obliquely downward and inward, and the left-right outside portion is formed to bend obliquely downward and outwardly. The left-right width between the outside ends of each of the lift arms  81   a ,  81   b  is greater than the left-right width between the left and right side structures  41 R,  41 L of the waste recovery station  40 , (that is, is approximately equal to the left-right width of the frame  22  of the first beach cleaner  20 .) When the second beach cleaner  50  enters between the left and right side structures  41 L,  41 R, the lift arms  81   a  and  81   b  ride on the left and right side structures  41 , respectively, whereby the second beach cleaner  50  is lifted up at a desired amount. 
     When the second beach cleaner  50  is lifted up as described above in the waste recovery station  40 , the net  56  provided at the rear portion of the frame  53  is elevated to a desired height. The net  56  is made to be turned around a hinge  82  located on the left side thereof (see  FIG. 18 ). Thus, the recovery work of the waste gathered in the net  56  can be facilitated. Incidentally, for the second beach cleaner  50 , the waste recovery work can be carried out with the second beach cleaner  50  not lifted up, that is, placed on the ground. 
     Additionally referring to  FIGS. 21 and 22 , a rear hinge bracket  83  is attached to the rear lift arm  81   b  located on the left side portion of the frame  53 . The rear hinge bracket  83  constitutes part of a hinge  82  pivotally supporting the left side of the net  56 . The rear hinge bracket  83  extends across the front and rear of the rear lift arm  81   b  on the proximal end thereof. The rear hinge bracket  83  is formed at its front and rear ends with front and rear walls  84 , respectively, which extend upward. The front and rear walls  84  are formed on the leading end side with front and rear through-holes  84   a , respectively, adapted to receive a hinge shaft  82   a . A rear hinge pipe  85  provided on the left side of the net  56  so as to be associated with the rear hinge bracket  83  is disposed between the front and rear walls  84 . The rear hinge pipe  85  is pivotally supported by the rear hinge bracket  83  via the hinge shaft  82   a  extending in the back and forth direction. 
     A frame-like support arm  86  is provided slightly forward of the rear lift arm  81   b . The support arm  86  has a slightly smaller left-right width than the lift arm  81   b . A front hinge bracket  87  having the same configuration as the rear hinge bracket  83  is supported by the support arm  86 . Front and rear walls  88  of the front hinge bracket  87  is formed with front and rear through-holes  88   a , respectively, adapted to receive a hinge shaft  82   a . A front hinge pipe  89  provided on the left side of the net  56  so as to be associated with the front hinge bracket  87  is disposed between the front and rear walls  88 . The front hinge pipe  89  is pivotally supported by the front hinge bracket  87  via the hinge shaft  82   a  extending in the back and forth direction. The hinge pipes  85 ,  89  and the hinge shaft  82   a  are provided coaxially with each other. 
     Referring to  FIGS. 16 and 17 , the net  56  is formed in a box shape opening forward and upward and includes a frame mainly made of e.g. steel pipes and wire meshes with meshes of desired sizes attached to the steel pipes. This net  56  is provided so as to extend from a position slightly forward of the center of the frame  53  to the vicinity of the rear end of the frame  53  in the back and forth direction. In addition, the net  56  is provided to have the left-right width approximately equal to that of the frame  53  in the leftward and rightward direction. The front end of the net  56  is spaced apart about 100 to 300 mm from the vicinity of the rear ends of the keels  54 , namely, the vicinity of the scrapers  55  in order to make it possible to satisfactorily capture the sand and waste scraped up by the keels  54  and the scrapers  55 . The front end of the net  56  is more preferably spaced apart about 250 mm from the vicinity of the rear ends of the keels  54  rearward. 
     Additionally referring to  FIG. 18 , the net  56  includes a bottom wall section  92 , a rear wall section  93  and left and right side wall sections  94 . The bottom wall section  92  is formed in a horizontally long rectangle as viewed from above. The rear wall section  93  is formed to rise almost upright from the rear edge of the bottom wall section  92 . The left and right side wall sections  94  slightly obliquely rise from both side edges of the bottom wall section  92  so as to be located leftward and rightward outwardly, respectively, as they go upward. The rear wall section  93  and the left and right side wall sections  94  form a surrounding section  91  which surrounds the circumference of the bottom wall section  92  except the front thereof in order to make it possible to collect the waste scraped by the keels  54  and the scrapers  55 . 
     The front portion of the bottom wall section  92  is a slant section  92   a  which slants slightly forwardly downwardly. A portion rearward of the slant section  92   a  is a horizontal portion extending almost horizontally. The horizontal portion is divided into a front horizontal section  92   b  and a rear horizontal section  92   c  by a lateral member extending in the leftward and rightward direction. 
     A wire mesh with a mesh size of 25 mm is attached to the slant section  92   a  of the bottom wall section  92 . A wire mesh with a mesh size of 12 mm is attached to the front horizontal section  92   b . A wire mesh with a mesh size of 8 mm is attached to the rear horizontal section  92   c.    
     As described above, the wire mesh of the bottom wall section  92  is set larger in mesh size as it goes forward. The relatively heavy damp sand of the sand scraped by the keels  54  and the scrapers  55  does not reach the rear portion of the bottom wall section  92 . Thus, the relatively heavy damp sand is satisfactorily eliminated, without occurrence of clogging, through the wire mesh with large meshes at the front portion of the slant section  92   a  of the bottom wall section  92 . On the other hand, relatively lightweight dry sand and the like reach the horizontal section of the rear side portion of the bottom wall section  92 , where they are eliminated through the wire meshes with middle and small meshes attached thereto but the waste is satisfactorily captured without being eliminated through the wire meshes. Incidentally, the wire meshes may be arbitrarily replaceable in the mesh sizes of about 6, 8, 10, 12 and 25 mm. 
     A side wall section  94  of the net  56  includes a side wall main body  94   a  and a rear projecting section  94   b . The side wall main body  94   a  is formed on each of side edges of the bottom wall section  92  so as to be in a rectangle long in the back and forth direction as viewed from the side. The rear projecting section  94   b  is formed on the rear side portion of the side wall main body  94   a  so as to be in a trapezoid as viewed from the side. The respective rear side portions of the side wall main body  94   a  and the rear projecting section  94   b  are extend vertically as viewed from the side so as to be linearly contiguous to each other. The rear wall section  93  of the net  56  is provided such that the rear side portions serve as its lateral side portions. The upper side portion of the side wall section  94  (rear projecting section  94   b ) is approximately equal in height to the upper side portion of the rear wall section  93 . 
     Front and rear hinge plates  95   a ,  95   b  are provided at front and rear portions, respectively, of the left side wall section  94  of the net  56  so as to be spanned between the intermediate and lower frame members of the side wall main body  94   a . Each of the hinge plates  95   a ,  95   b  is formed like a plate shaped in an almost square as viewed from the side. Each of the hinge plates is appropriately cut out to leave its outer edge portion and orthogonal portions. In addition, the front and rear edge portions of each of the hinge plates  95   a ,  95   b  are bent leftward and rearward inwardly to form reinforcing flanges. The front and rear hinge pipes  85  and  89  are integrally joined to the outer side surfaces of the hinge plates  95   a  and  95   b , respectively. 
     A grip  96   a  is provided at a front upper side (above the front hinge plate  95   a  in the left side wall section  94 ) of each of the left and right side wall sections  94  so as to project upward from the upper edge thereof. The grip  96   a  is formed in a U-shape opening downward as viewed from the side. The grip  96   a  is provided to have an upper side portion extending in the back and forth direction and to be inclined so as to be protrude slightly outwardly from the side wall section  94  corresponding thereto. Grips  96   b  are provided at left and right upper portions of the rear wall sections  93  so as to project upward from the upper edge thereof. The grip  96   b  is formed in a U-shape opening downward as viewed from the rearward. The grip  96   b  is provided to have a upper side portion extending in the leftward and rightward direction and to extend almost vertically so as to be located flush with the rear wall section  93 . 
     The left side portion of the net  56  is pivotally and supportably connected to the left side portion of the frame  53  via the hinge  82  as described above. The net  56  is turned via the hinge  82  so as to lift the right side portion of the net  56  configured as above upward, bringing the bottom wall section  92  into an almost upright state. In this state, the waste collected in the net  56  drops on the left side wall section  94  and is discharged along the left side wall section  94  to the outside of the net  56 . 
     Since the grips  96   a ,  96   b  are attached to the appropriate portions (at least a portion opposite to the hinge  82 ) of the surrounding section  91  of the net  56 , the recovery work of the waste by turning the net  56  can be facilitated. The hinges  82  are arranged on one short side (left side) of the horizontally long net  56 . Therefore, when the net  56  is raised, the length from a pivotal shaft to the operating part (the right grips) can be ensured to facilitate the turning operation of the net  56 . 
     The left side wall section  94  (namely, the wall section close to the hinge  82  of the surrounding portion  91 ) of the net  56  is a wall portion to which a plate member is attached to satisfactorily discharge the waste. The upper edge portion of the left side wall section  94  of the net  56  is set to protrude leftward relative to the left side structure  41 L of the waste recovery station  40  in the upright state of the bottom wall section  92  (see  FIG. 18 ). If a waste collection container is disposed leftward adjacent to the waste recovery station  40 , the waste collected in the net  56  is directly thrown into the container with the left side wall section  94  sloped. The right side wall section  94  and rear wall section  93  of the net  56  serve as net portions to which wire meshes with large meshes are attached in order to prevent the waste thrown in the net  56  from dropping. 
     Left front and rear end stoppers  97   a ,  97   b  are respectively provided on the left longitudinal member  51  of the frame  53  so as to position the left front and rear ends of the net  56 . Similarly, right front and rear end stoppers  97   a ,  97   b  are respectively provided on the right longitudinal member  51  of the frame  53  so as to position the right front and rear ends of the net  56 . Each of the stoppers  97   a ,  97   b  includes an almost vertical position-restriction surface in abutment against the front or rear end of the net  56 ; and a turn guide surface which is contiguous to the position restriction surface from above so as to be inclined upward. The stoppers are each detachably attached to the longitudinal member  51  using e.g. bolts or the like. 
     The front ends of both sides of the net  56  in the usage state (the state where the bottom wall section  92  is almost horizontally abutted against the frame  53 ) are abutted against the position restriction surfaces of the left and right front end stoppers  97   a . In addition, the rear ends of both sides of the net  56  in the usage state are abutted against the position restriction surface of the left and right rear end stoppers  97   b . Thus, the net  56  can be positioned with respect to the frame of the net  56  in the back and forth direction. When the net  56  is turned to be brought from the upright state into the usage state, the front and rear ends of both sides of the net  56  are guided by the guide surfaces of the stoppers  97   a ,  97   b  and the net  56  is smoothly returned to a predetermined position on the frame  53 . 
     Referring to  FIG. 23 , the attachment positions of the stoppers  97   a ,  97   b  to the longitudinal members  51  may be made movable forwardly and backwardly. In this case, the lengths of the hinge pipes  85 ,  89  on the left side of the net  56  are each made shorter than the distance between the front and rear walls  84  of the front hinge bracket  87  and between the front and rear walls  88  of the rear hinge bracket  83 . This makes it possible to shift the net  56  back and forth in response to the shift of the stoppers  97   a ,  97   b . In this way, the front end position of the net  56  can be easily changeable according to the conditions of the sand area. This makes it possible to enhance the waste capture performance of the second beach cleaner  50 . 
     Next, a description is made of a schematic procedure for cleaning a sandy beach using the beach cleaners  20 ,  50 . 
     The waste recovery station  40  which has been loaded on the trailer  13  as shown in  FIG. 1  and carried to a predetermined site on the sandy beach is installed thereat. In  FIG. 1 , the waste recovery station  40  which has been integrally assembled is loaded on the trailer  13 . However, needless to say, the waste recovery station  40  may be loaded on the trailer  13 , while being divided into the side structures  41  and the connecting members  42  as described above. In this case, the work for installing the waster recovery station  40 , including loading and unloading it on and from the trailer  13 , can be facilitated. Incidentally, in the waste recovery station  40  in  FIG. 1 , only the foot members  45  are removed therefrom. 
     The hardness of the sandy beach is next measured. The hardness is a criterion for determining the number of the sand pins  23  of the first beach cleaner  20 , the amount of digging the keels  54  and scrapers  55  of the second beach cleaner  50  and the like into the sand. This measurement is performed by allowing e.g. an iron pile with a predetermined size to freely fall on a sandy beach. The hardness of the sandy beach is evaluated at three levels (soft, standard and hard) on the basis of the average of the measurements. The number of the sand pins  23 , the weight of the weight  34 , the attachment height of the ski legs, the positions of connecting the connecting rod  38  to the tow portions  37 ,  67  and the like are determined in accordance with the hardness of the sandy beach thus measured and the condition of scattered waste or the like. 
     The first beach cleaner  20  is then unloaded from the trailer  13  and subjected to the settings based on the measurements of the hardness of the sandy beach. The first beach  20  is towed by the vehicle  1  to run on the sandy beach at a constant speed. In this case, as shown in  FIG. 24 , the running trajectory is obtained by the vehicle  1  and the first beach cleaner  20  which turn along almost-squares, shifting their turning position in the predetermined area on a sand area, thereby making it possible to sweep the predetermined area surely and evenly. The first beach cleaner  20  collects relatively large waste on the sandy beach while digging the sand pins  23  in the sand, being subjected to relatively large travel resistance. Thus, the traveling speed is set at as low as about 5 to 10 km/h. 
     When the first beach cleaner  20  runs on the sandy beach as described above to collect a predetermined amount of waste under the frame  22 , it once returns to the waste recovery station  40 , where the waste collected is recovered. In this case, the vehicle  1  passes between the left and right side structures  41  of the waste recovery station  40  and then the first beach cleaner  20  enters between the left and right side structures  41 . At this time, the left and right lift arms  39  ride on the left and right side structures  41 , respectively, whereby the first beach cleaner  20  is lifted up at a predetermined amount (see  FIG. 13 ). In the state, the vehicle  1  and the first beach cleaner  20  are stopped and the waste is allowed to drop on the sand area for recovery work. Thereafter, the vehicle  1  and the first beach cleaner  20  are made to run again to repeat the waste collecting work described earlier. 
     After the first beach cleaner  20  cleans the predetermined area, the second beach cleaner  50  is towed to run on the same area to collect relatively small waste on the sandy beach. In this way, the second beach cleaner  50  is used after the first beach cleaner  20  is used; therefore, the keels  54 , the scrapers  55 , the net  56  and the like which deal with small waste can be prevented from being damaged. The running trajectory of the second beach cleaner  50  is the same as that of the first beach cleaner  20 . When the second beach cleaner  50  runs on a sandy beach, the sandy beach is soft because it has been broken up by the action of the first beach cleaner  20 . In addition, it is necessary for the keels  54  and the scrapers  55  to scrape out sand and waste. Thus, the traveling speed of the second beach cleaner  50  is set to about 15 to 25 km/h, which is slightly faster than that of the first beach cleaner  20 . 
     While the second beach cleaner  50  runs on the sandy beach, the keels  54  and the scrapers  55  scrape out relatively small waste together with sand, which is collected in the net  56  at the rear portion of the frame  53 . The net  56  on the bottom wall section  92  is set such that the wire meshes are smaller in mesh size in the order from the front side. Thus, the waste collected is unlikely to drop and the wire meshes can be prevented from clogging. 
     After the second beach cleaner  50  runs on the sandy beach to collect a predetermined amount of waste in the net  56  as described above, it once returns to the waste recovery station  40 , in which the waste collected is recovered from the second beach cleaner  50 . In this recovery work, when the vehicle  1  passes between the left and right side structures  41  of the waste recovery station  40  and then the second beach cleaner  50  enters between the left and right side structures  41 , the front and rear, left and right lift arms  81   a ,  81   b  ride on the left and right side structures  41  to lift up the second beach cleaner  50  at a predetermined amount. In the state, the vehicle  1  and the second beach cleaner  50  are stopped and the net  56  is turned to recover the collected waste. Thereafter, the vehicle  1  and the second beach cleaner  50  are made to run again to repeat the waste collecting work described earlier. 
     As described above, the first beach cleaner  20  of the embodiment includes the plurality of longitudinal members  21  extending in the traveling direction spaced widthwise apart from each other, forming the floor grate-like frame  22 . The longitudinal members  21  are provided with the plurality of sand pins  23  projecting downward therefrom. The frame  22  is provided at its front end with the tow portion  37 . The first beach cleaner  20  is towed by the towing vehicle  1  to run on a sand area while the sand pins  23  scrape and collect waste scattered thereon. The sand pins  23  are detachably attached to the longitudinal members  21 . 
     With this configuration, the number of the sand pins  23  can be increased or reduced. If the sand area has large resistance, the number of the sand pins  23  is reduced. If the sand area has small resistance, the number of the sand pins  23  is increased. Thus, the amount of burying the sand pins  23  in the sand area can be optimized to thereby enhance waste collection performance. 
     Since the first beach cleaner  20  is provided with the weight mount portion  31  on the frame  22 , the amount of burying the sand pins  23  in the sand area can be also adjusted by the heft of the weight, thereby further enhancing the waste collection performance. 
     The present invention is not limited to the embodiment described above. For example, like a first beach cleaner  120  shown in  FIG. 27 , waste collecting portions  21   a  may be provided at portions, of the longitudinal member  21 , between the sand pins  23  aligned in the back and forth direction in the frame  22  by bending the longitudinal members  21  upward. This prevents the frame  22  from riding on the waste scraped and collected to float. Thus, the amount of sinking of the sand pins  23  in the sand is maintained at an appropriate amount, thereby satisfactorily maintaining the waste collection performance. 
     Alternatively, like a first beach cleaner  220  shown in  FIG. 28 , joint portions  22   a  bendable up and down and (or) right and left may be provided at portions, of the frame  22 , between the sand pins  23  aligned in the back and forth direction in the frame  22 . This prevents the frame  22  from floating due to the frame  22  riding on the waste scraped and collected or to the influence of the undulation of the sand area. Thus, the waste collection performance can be satisfactorily maintained similarly to the above. 
     The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.