Patent Publication Number: US-9409314-B2

Title: Concrete power saw

Description:
FIELD OF THE INVENTION 
     This invention relates to power saws which typically rotatably drive a industrial grade diamond impregnated blades, such saws being adapted for cutting slots into concrete slab surfaces. More particularly, this invention relates to such saws which are adapted for collecting and handling emanations of concrete dust and cuttings during slot cutting operations. 
     BACKGROUND OF THE INVENTION 
     Conventional gasoline or electric motor driven concrete power saws are conventionally used for cutting slots or contraction joints within concrete slabs, such as concrete roadways, sidewalks, foundation floors, and tarmacs. During such cutting operations, concrete dust cuttings commonly and undesirably emanate from the cutting site to cover surfaces and foul the air. A primary component of concrete dust is silica, and breathing of such dust is known to contribute to onset of silicosis of the lungs. Due to concrete&#39;s common coal or fly ash content, concrete dust cuttings may also include toxic heavy metals and metalloids such as lead and arsenic. In addition to the harmful health effects of concrete dust, such dust is often difficult and time consuming to clean from floor surfaces and other surfaces such as vehicles and building fixtures and walls. 
     Known vacuum based systems for handling and reducing such concrete dust are undesirably mechanically complex and cumbersome, and are not economically provided. 
     The instant inventive concrete power saw solves or ameliorates the problems, defects, and deficiencies discussed above by providing specialized concrete dust capturing and conveying mechanisms which effectively reduce emanations of concrete dust without the provision of any vacuum actuated system or equipment. 
     BRIEF SUMMARY OF THE INVENTION 
     A first structural component of the instant inventive concrete saw comprises a rollable trolley. In a preferred embodiment, the rollable trolley comprises a rigid and substantially rectangular plate steel deck having a pair of fixed rear wheels, and having at least a first adjustable height front wheel. The adjustability of the trolley&#39;s front wheels facilitates adjustability of the cutting depth of the concrete saw machine and alternatively facilitates maintenance of a constant cutting depth as diameters of rotary blades vary. 
     A further structural component of the instant inventive concrete saw comprises motor means which are fixedly attached to the rollable trolley. In the preferred embodiment, the motor means are mounted directly upon an upper surface of the rollable trolley, the motor means utilizing the trolley as a support pedestal. 
     In a preferred embodiment, the motor means comprise a four cycle air cooled gasoline engine. Suitably, the motor means may alternatively comprise a two cycle engine. Also suitably, the motor means may further alternatively comprise an electric motor. For indoor operation, the motor means may suitably comprise a propane gas powered internal combustion engine. The motor means necessarily has a rotary power output which is at least utilized for rotatably driving the machine&#39;s saw blade. The motor means preferably further drives via provided secondary turning means the machine&#39;s below described dust conveying and apparatus. 
     A further structural component of the inventive concrete saw comprises a rotary concrete cutting blade. Preferably, the blade is of the type having impregnated industrial grade diamonds for longevity in concrete cutting use. In a preferred embodiment, the blade component is connected operatively to the motor means&#39; rotary power output by a journal axle, belt, and pulleys combination, such combination positioning the blade for cutting impingement against underlying concrete slab surfaces. 
     A further structural component of the instant inventive concrete saw comprises a specially configured blade shroud which is preferably fixedly and rigidly mounted to a lateral side of the rollable trolley. The rigid mount of the shroud in combination with a rigid journal axle mount of the blade to the shroud and/or the trolley advantageously requires that blade positioning and movement be coincident with trolley positioning and movement. 
     In the preferred embodiment, the machine&#39;s shroud component has a plurality of side walls (preferably consisting of a lateral wall, an oppositely lateral wall, a front wall, a rear wall), a ceiling, and a floor. Preferably, the floor component comprises a slide plate which is adapted for dynamic vertical adjustment and movement. In the preferred embodiment, the combination of such shroud walls, ceiling, and floor forms, defines, and encloses a dust containment space which functions as a first stage handling space for minimization of emanations of concrete dust during concrete saw cutting. 
     A further structural component of the instant inventive concrete saw comprises an Archimedes&#39; screw which operates similarly with a tube mounted helical blade auger for conveyance of granular materials. The Archimedes&#39; screw component preferably comprises a hollow tube which receives and rotatably houses a helically bladed bit or screw. In the preferred embodiment, the lower and forward input end of the Archimedes&#39; screw is configured integrally with the blade shroud so that the Archimedes&#39; screw is forwardly supported and so that its input end resides within the shroud&#39;s dust containment space. 
     Further structural components of the instant inventive concrete saw comprise the secondary turning means which are connected operatively to the opposite output end of the Archimedes&#39; screw component, such opposite end preferably being positioned upwardly and rearwardly from the shroud. Suitably, the turning means may comprise a secondary and separate electric motor or internal combustion engine whose rotary power linkage is connected to the output end of the Archimedes screw&#39;s helical bit. However, in the preferred embodiment, the turning means derives its rotary power from the rotary power output of the machine&#39;s primary motor means. In a preferred embodiment, a drive linkage comprising a second belt and pulleys combination in further combination with a rotational power redirecting gear train is provided for rotatably driving the Archimedes&#39; screw. Accordingly, the instant invention advantageously allows a single engine to simultaneously rotatably drive the machine&#39;s blade (which generates the concrete dust) and drive the Archimedes&#39; screw (which conveys the concrete dust). 
     A further Component of the instant inventive concrete saw comprises a receptacle for the receiving concrete saw cuttings. In the preferred embodiment, the receptacle comprises a bin which rolls upon and is supported by a second rollable trolley, such trolley moving in train with the first rollable trolley. Preferably, the output end of the Archimedes&#39; screw is equipped with an output chute which may be downwardly directed for communication with an upper opening of the receptacle. 
     In operation of the instant inventive concrete saw, the Archimedes&#39; screw preferably continually turns during concrete sawing operations. Concrete dust and cuttings, which are continuously drawn and thrown by the rotary blade from the sawn slot and into the shroud&#39;s dust containment space, advantageously fall into or are directed into the Archimedes&#39; screw&#39;s input end. Continuous rotation of the Archimedes&#39; screw&#39;s helical screw flights carries such saw cuttings upwardly and rearwardly along the tube to emit into the chute, and to fall downwardly therethrough into the trailing receptacle. 
     As a result of operation of the inventive saw, dust emanations at and about the slot cutting site are minimized with the majority of the concrete cuttings being conveyed into and stored within the receptacle for proper disposal. 
     Accordingly, objects of the instant invention include the provision of a concrete cutting saw which incorporates structures, as described above, and which arranges those structures in relation to each other, in manners described above, for achievement of the beneficial functions described above. 
     Other and further objects, benefits, and advantages of the instant invention will become known to those skilled in the art upon review of the Detailed Description which follows, and upon review of the appended drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a preferred embodiment of the instant inventive concrete saw. 
         FIG. 2  redepicts in magnified view a portion of the structure presented in  FIG. 1 , the view of  FIG. 2  including cutaway sections and dashed line structures in explanation of internal mechanical components. 
         FIG. 3  is a partial sectional view as indicated in  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT 
     Referring now to the drawings and in particular to Drawing  FIG. 1 , a preferred embodiment of the instant inventive concrete saw is referred to generally by Reference Arrow  1 . The saw  1  preferably comprises a first trolley  2  having a pair of rear wheels  4 , and at least a first front wheel  5 . In the preferred embodiment, the front wheel  5  is equipped with a height adjustment screw  7  for selective adjustment of the elevation of the front edge of the first trolley  2  with respect to the upper surface of a concrete slab  100 , such height adjustment enabling alterations and maintenance of the saw&#39;s cutting depth in a manner discussed below. 
     Referring further to  FIG. 1 , a gasoline powered internal combustion engine  8  is securely mounted to the upper surface of the deck of the rollable trolley  2 . Such engine  8  is intended as being representative of other suitable motor means such as electric motors which are considered to fall within the scope of the invention. 
     Referring simultaneously to all figures, a concrete cutting blade  24  is connected operatively to the rotary drive output  10  of the engine  8 . The blade  24  is rotatably mounted by means of a journal axle  22  which extends through an aperture  51  within a left or oppositely lateral shroud wall  19 , which itself is rigidly connected to the trolley  2  by means of “L” flange  3  and connector arm  18 . The oppositely lateral end of axle  22  is rotatably supported upon the lateral end of trolley  2  by rotary bearing  49 . A pulleys  12  and  16 , and belt  14  combination, translates rotary power from the engine&#39;s rotary output  10  to the axle  22  and to the blade  24 . 
     Referring simultaneously to  FIGS. 1 and 3 , the blade shroud has a lateral side wall  38 , an oppositely lateral side wall  19 , a ceiling  20 , a back wall  17 , a front wall  23 , and a slide plate configured floor  34 . Such combination of walls  38 , 19 , 17 , 23 , ceiling  20 , and floor  34  advantageously forms and defines a dust containment space  37 . In a preferred embodiment, the ceiling  20  is arcuately curved so that concrete dust  106   l  which is thrown and churned within the containment space  37  is directed upwardly and laterally through port  44  for handling and conveyance in the manner described below. 
     An Archimedes&#39; screw component preferably comprising a hollow tube  41 , a drive axle  48 , and a helical screw flight  46 , is necessarily provided. A lower intake end of the Archimedes&#39; screw  41 , 46 , 48  is preferably positioned at and opens into the shroud&#39;s interior dust containment space  37 . In the preferred embodiment, the shroud&#39;s lateral wall  38  is laterally stepped or offset at an elevation above the slide plate floor  34  and below the ceiling  20 , such offset advantageously forming a dust collecting land  40 . 
     In the preferred embodiment, the shroud&#39;s dust collecting land  40  is concavely configured to present a cylindrical curvature which is closely fitted for nesting receipt of the cylindrical periphery of the helical blade flights  46 . In the preferred embodiment, the forward end of the Archimedes&#39; screw&#39;s drive axle  48  is supported by a rotary bearing  50  which is mounted to the shroud&#39;s front wall  23 , such bearing  50  effectively closing the forward end of the tube  40 , 41 . 
     The shroud  38 , 20 , 19 , 23 , 34  is preferably longitudinally seamed to divide the shroud into separable lateral and oppositely lateral “clamshell” segments. In the preferred embodiment, the lateral segment includes the lateral wall  38 , the curved dust collecting land  40 , and the rotary bearing  50 , the input end of the Archimedes&#39; screw component preferably being integral with such lateral shroud segment. The oppositely lateral segment of the shroud preferably comprises the lateral wall  19  in combination with the curved ceiling  20 . Hand turnable attachment screws  52  which extend through mounting flanges  39  and  21  are preferably provided for removably connecting the shroud&#39;s lateral and oppositely lateral segments. Such “clamshell” mode of connection of the shroud&#39;s segments facilitates easy access to the blade  24  for mechanical maintenance. 
     Referring in particular to  FIG. 2 , the rearward end of the Archimedes&#39; screw preferably includes an output port  43  (shown as a dotted line) which opens tube  41 . An output chute  80  communicates with such port  43  for directing the concrete cuttings and dust output of the Archimedes&#39; screw through an upper port  74  of a rearwardly trailing concrete dust receptacle  70 . 
     The rearward end of the axle  48  of the Archimedes&#39; screw is preferably rotatably driven by turning means, preferably in the form of a belt  86  and pulleys  84 , 88 , 89  combination. Such belt and pulleys combination translates rotary power from the engine&#39;s rotary power output  10  to a transverse axle  81  which is rotatably mounted within a power transfer box  82 . The transverse axle  81  rotatably drives a worm gear  91  which engages and turns a pinion gear  93  which is axially joined with the Archimedes&#39; screw&#39;s drive axle  48 . A universal joint  95  advantageously accommodates for angular deflections of the Archimedes&#39; screw with respect to the power transfer box  82 . The universal joint  95  further facilitates disassembly and disconnection of the clamshell halves of the shroud without requiring disconnection of the drive shaft  48 . A flexible boot  97  is provided to facilitate such clamshell disconnection. A belt and pulley shroud  90  is preferably provided for protecting operators from pinch points inherent in such power transfer system. 
     The Archimedes&#39; screw&#39;s turning means preferably incorporates a tensioning pulley  92  mounted upon a pivot arm  94 . Such tensioning pulley  92  may be actuated by hand manipulation of lever  98  which rotates the pivot arm  94  via bar linkage  96 . Rearward pivoting of lever  98  engages the turning means by tightening the belt  86  against drive pulleys  89  and  84 . Forward deflection of lever  98  raises the tensioning pulley  92 , causing the belt  86  to slacken to allow continued rotary motion of the rotary power output  10  while the axle  48  and its screw flights  46  remain motionless. Pulley  88  constitutes an idler pulley which continues to guide belt  86  while such belt is frictionally disengaged. 
     While the mechanical combination of the belt  86 , pulleys  89 ,  88 ,  92 , and  84 , transverse axle  81 , worm gear  91 , and pinion gear  93  constitutes a preferred means for turning the Archimedes&#39; screw axle  48 , other turning means such as an independent electric motor or an independent internal combustion engine are considered to fall within the scope of the invention. Other variously configured and commonly known rotary power redirecting drive trains, such as bevel gear and drive axle combinations, are also considered to fall within the scope of the invention. The depicted belt, pulleys, and gears turning means combination is intended as being representative of such alternative turning means. 
     Referring simultaneously to  FIGS. 1 and 2 , a height adjustable lateral wheel  58  is preferably provided, such wheel  58  being rotatably mounted upon a journal axle  60  whose lateral end is configured as a hand turnable “T” for operator assembly and disassembly. The oppositely lateral end of the journal axle  60  is preferably helically threaded for removably engaging a slide block  61 . Block  61  is preferably slidably received within a slide mount  54  which exposes the block  61  and axle  60  beneath a vertical slide slot  56 . Clockwise and counter-clockwise turning of jack screw  62  selectively raises and lowers the wheel  58 . In a preferred mode of operation, screws  62  and  7  are turned in a coordinated fashion so that the lower ends of wheels  58  and  6  reside at a common elevation with respect to the deck of trolley  2 . Such coordination of adjustable heights maintains blade  24  at a perpendicular orientation with respect to the upper surface  102  of the concrete slab  100  while allowing the machine&#39;s operator to precisely control the depth of a concrete slot  104  which is cut by blade  24 . As the diameter of blade  24  varies due to wear, such coordinated manipulation of screws  62  and  7  may assure slot depth consistency during prolonged usage of the machine  1 . 
     Referring further simultaneously to  FIGS. 1 and 2 , the slide plate configured floor  34  has a blade slot  47 . The shroud is preferably specially adapted for alternative upward and downward telescoping motion of the plate  34  and slot  47  with respect to the lower ends of the side walls  38  and  19 , rear wall  17 , and front wall  23  of the shroud. In order to facilitate such telescoping motion, an upwardly extending elastomeric flange  36  is preferably attached to the slide plate  34 , such flange&#39;s lower end being fixedly attached to a peripherally extending mounting ridge  35 . In the preferred embodiment, the elastomeric flange  36  is closely fitted to the inner dimensions of the walls  38 ,  19 ,  17 , and  23  so that concrete dust  106   l  does not escape between the peripheral seam formed between such flange and such walls. 
     The telescoping means which facilitate the upward and downward motions of the slide plate  34  preferably further comprise front and rear spring biased quill and shaft combinations  26  and  30 , such quill and shaft combinations being rigidly mounted to the first trolley  2  by means of the rigidly mounted “L” flange  3  and rigid oppositely laterally extending bracket arms  28  and  32 . Springs  33  which co-axially receive shafts  31  within the quill portions of the quill and shaft combinations  26  and  30  advantageously allow the lower ends of such shafts  31  to float upwardly and downwardly in a spring damped and normally downwardly extended fashion. Such shaft lower ends are preferably pivotally attached to the oppositely lateral edge of slide plate  34  by front and rear pivot mounts  53  (the rear pivot mount not being within views). 
     In operation of the above described slide plate telescoping means, a pebble  101 , for example, may reside on the slab surface  102  in front of slide plate  34 . Pebble  101  is intended as being representative of small changes or fluctuations in the grade or surface texture of the concrete surface  102 . Upon contact of the forward end of the slide plate  34  with the pebble  101 , the front end of the slide plate  34  deflects upwardly, driving shaft  31  upwardly against spring  30 . Simultaneously, the sealing flange  36  slidably moves against the interior surfaces of the shroud&#39;s side walls without any breakage or interruption of the flange&#39;s dust sealing function. Continued forward passage of the slide plate  34  over pebble  101  allows the front end of the slide plate  34  to normally counter-deflect downwardly (through the action of the front quill and shaft combination  30 ) while the rearward end of the slide plate  34  in succession deflects upwardly (through the action of the rear quill and shaft combination  26 ). Accordingly, the telescoping means associated with the slide plate  34  advantageously allow the machine and the slide plate  34  to move over small concrete surface irregularities and protuberances, such as pebble  101 , while continuously performing dust containment and sealing, and without any gross disturbance or variation of the cutting depth of the blade  24 . 
     Referring simultaneously to  FIGS. 1 and 2 , to effectively collect and temporarily store concrete dust cuttings, the receptacle  70  having a removable lid  72  is preferably mounted upon and carried by a second rollable trolley  71 . Such second trolley is preferably rearwardly supported by a rear caster wheel  78 , and is forwardly supported and towed by bracket arms  76  which securely and pivotally interconnect the second trolley  71  with the first trolley  2 . 
     Referring simultaneously to all figures, the machine&#39;s operator may, for example, desire to cut a one inch depth expansion slot  104  within a concrete slab  100 . Accordingly, the operator may turn “T” handle screws  62  and  7  until the lower ends of wheels  58  and  5  upwardly retract to the elevation which overlies that of the lower end of blade  24  by one inch. Thereafter, engine  8  may be actuated, and lever  98  may be pulled rearwardly, causing the Archimedes&#39; screw turning belt  86  to frictionally engage and rotatably drive the helical bit  46  and axle  48  within tube  41 . Upon lowering of the blade  24  into the surface  102  of the concrete slab  100 , the blade  24  draws and throws (in the upward direction indicated by the arrows drawn upon  FIG. 3 ) concrete dust and cuttings  106   l  into the interior space  37  of the shroud. Continued rotary motion of the blade  24  minimizes accumulations of concrete dust  106   l  upon floor  34 , such blade continually churning and rapidly throwing the dust within and about such space. Such rotary motion and dust throwing effect causes portions of the dust to continuously impinge against the curved ceiling  20 . The curved ceiling  20  advantageously causes the dust  106   l  to carom laterally through port  44  to fall laterally and downwardly over the curved dust capturing land  40  to accumulate therein as concrete dust  106   h.    
     The continuous rotary turning of the screw flights  46  within the interior space  42  of the tube  41  draws such dust  106   h  upwardly and rearwardly through tube  41  to emit through outlet port  43 , such dust immediately falling downwardly through chute  80  and into and through  72  of receptacle  70  to reside as collected dust  106   r . As the slot cutting progresses along the slab  100 , such dust collection and Archimedes&#39; screw actuated dust conveyance continues, advantageously preventing harmful emanations of concrete dust at and about the cutting site. 
     To assist an operator in guiding the machine  1  along the path of slot  104 , a “T” handle  6  is preferably rigidly mounted to the rearward end of the rollable trolley  2 . 
     While the principles of the invention have been made clear in the above illustrative embodiment, those skilled in the art may make modifications in the structure, arrangement, portions and components of the invention without departing from those principles. Accordingly, it is intended that the description and drawings be interpreted as illustrative and not in the limiting sense, and that the invention be given a scope at least commensurate with the appended claims.