Patent Publication Number: US-2021178633-A1

Title: Dust Collecting Concrete Saw

Description:
FIELD OF THE INVENTION 
     This invention relates to motor powered walk behind concrete cutting saws. More particularly, this invention relates to such saws which are adapted for vacuum collection of concrete saw dust and cuttings at the cutting site, and for carriage of the dust and cuttings to a dust container. 
     BACKGROUND OF THE INVENTION 
     Commonly known and commonly configured walk behind concrete saws include a rigid rectangular base or chassis frame having an upwardly and rearwardly extending handle. Such handle and base frame combination functions similarly with or constitutes a hand truck mechanism which carries motor and saw cutting apparatus which are fixedly mounted upon the base frame. Such concrete saw hand truck component conventionally presents a plurality of wheels which are fixedly attached to and extend downwardly from the base frame. Concrete slab cutting operation of such concrete saws commonly generates large quantities of fine crystalline silica dust particles which become airborne, often undesirably constituting respirable particles. Such airborne respirable silica particles are known to afflict workers in the vicinity of the saw with silicosis of the lung. 
     Known adaptations of concrete saws for simultaneous cutting and vacuum collection of concrete dust commonly incorporate electric powered, gasoline powered, or propane powered vacuuming apparatus. Such vacuum equipped concrete saws typically require the employment of a second worker to operate and maneuver the vacuum, undesirably increasing labor costs incurred during concrete cutting operations. 
     The instant inventive concrete saw advantageously allows a single worker to perform vacuum assisted walk behind concrete saw cutting of a slab by incorporating as a component of the saw a second hand truck component attached in train with respect to the first hand truck component. The inventive adaptation incorporating such second hand truck component advantageously allows a single worker to simultaneously perform concrete cutting and concrete dust vacuuming, and to benefit from other functional advantages facilitated by the second hand truck. 
     BRIEF SUMMARY OF THE INVENTION 
     The instant inventive saw is intended to be used for cutting concrete slab fracture line guiding slots within concrete slab surfaces. Concrete slabs typically crack following initial fabrication due to motions of the slab and the underlying earth resulting from temperature and moisture level induced expansion and contraction cycles. Slots cut in a grid pattern within the slab shortly after fabrication desirably cause such cracking to coincide with the grid pattern. 
     First structural components of the instant inventive saw comprise front and rear hand trucks. In a preferred embodiment, each of the saw&#39;s hand truck components has a lower foot plate or base, and has an upwardly extending handle. A lower end of each hand truck&#39;s handle is preferably fixedly attached to a proximal end of said each hand truck&#39;s foot plate or base component. 
     Further structural components of the instant inventive concrete saw comprise front and rear pluralities of wheels. The wheel pluralities are preferably respectively fixedly attached to and respectively extend downwardly from the bases of the front and rear hand trucks. Distally positioned wheels attached to the base of the rear hand truck are preferably caster wheels which swivel about a vertical axis in order to prevent such wheels from resisting turning of the saw during use. 
     A further structural component of the instant inventive saw comprises a motor and rotary cutting blade or cutting wheel combination. In a preferred embodiment, such combination is fixedly attached to and is supported upon the front hand truck&#39;s base component. In such embodiment, the combination&#39;s motor component is a gas powered internal combustion engine, and the cutting wheel is positioned and rotatably driven at a lateral position with respect to the motor and the base. 
     A further structural component of the instant inventive concrete saw comprises a motor powered vacuum which is fixedly attached to and is supported upon the rear hand truck component via attachment to the rear hand truck&#39;s handle, or via attachment to the rear hand truck&#39;s base. In the preferred embodiment, the motor powered vacuum is cordless, incorporating an on-board rechargeable battery which powers an electric motor, such motor driving a centrifugal vacuum drawing air impeller. Such motor and air impeller combination is preferably mounted to the top of a vacuum cyclonic canister whose lower dust output opening communicates with a concrete dust cuttings collection bag. 
     In the preferred embodiment, the motor, impeller, and cyclonic canister assembly are securely mounted to the rear hand truck&#39;s handle (as opposed to a suitably alternate mounting to the rear hand truck&#39;s base), while the rear hand truck&#39;s base supports concrete dust and cuttings contained within a flexible concrete cuttings collection bag. 
     A further structural component of the instant inventive concrete saw comprises a vacuum housing which enshrouds an upper end of the cutting wheel. The vacuum housing is mounted to the front hand truck&#39;s base or other suitable mounting point. Such housing defines, in combination with the upper surface of the concrete slab, a substantially enclosed space within which vacuum extraction of concrete dust will occur. 
     A further structural component of the instant inventive concrete saw comprises a vacuum tube which spans between and operatively interconnects the preferably provided cyclonic canister and vacuum housing. Operation of the motor powered vacuum induces negative vacuum pressure within the vacuum tube, evacuating air and dust cuttings from the interior of the vacuum housing. In a preferred embodiment, the input end of the vacuum tube is located at a forward and upper end of the vacuum housing. Such preferred positioning of the vacuum tube&#39;s input end derives a functional advantage with respect to the common rotation of the cutting wheel or blade wherein the forward flights of the blade&#39;s cutting teeth move upwardly toward the forward and upper end of the housing&#39;s interior. Dust and cuttings are advantageously thrown by such cutting teeth toward the overlying tube input end. 
     A further structural component of the instant inventive concrete saw comprises a trailering latch which interconnects the front and rear hand trucks. In the preferred embodiment, the trailering latch component is releasable, and is easily and conveniently attachable and detachable. Engagement of the trailering latch component advantageously positions the rear hand truck rearwardly from the front hand truck so that frontward propulsion applied to the front hand truck&#39;s handle simultaneously forwardly drives the forward hand truck and its attached motor, vacuum housing, and cutting wheel, while simultaneously forwardly pulling in a trailering fashion, the rearward hand truck including its attached and supported vacuuming components. The instant inventive saw advantageously allows a single operator to simultaneously perform vacuum assisted concrete cutting. Upon disconnection of the rear hand truck, the operator may utilize the separated rear hand truck for convenient transport and offloading of bagged concrete cuttings. 
     Accordingly, objects of the instant invention include the provision of a concrete saw for cutting control joints, slots, or grooves within concrete slab surfaces which incorporates structures, as described above, and which arranges those structures in relation to each other in manners described above for the achievement and performance of beneficial functions, as 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 the instant inventive concrete saw for cutting relief slots in concrete slab surfaces. 
         FIG. 2  is a side view of the concrete saw of  FIG. 1 . 
         FIG. 3  presents an alternative perspective view of the concrete saw of  FIG. 1 , the view of  FIG. 3  showing rearward vacuum components with forward saw components unlatched and removed. 
         FIG. 4  redepicts the concrete saw of  FIG. 1 , the view of  FIG. 4  further showing a worker operating the concrete saw. 
         FIG. 5  is an alternative and partial perspective view of components of the  FIG. 1  concrete saw. 
         FIG. 6  is a further alternative partial perspective view of components of the  FIG. 1  concrete saw. 
     
    
    
     DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT 
     Referring now to the drawings and in particular to Drawing  FIGS. 1 and 4 , the instant inventive concrete saw is referred to generally by Reference Arrow  1 , such saw being intended for use for cutting slots, grooves, or control joints within a concrete slab as exemplified by slot  106  within slab surface  104 . 
     The instant inventive saw  1  comprises a front hand truck component which is referred to generally by Reference Arrow  3 , and a rear hand truck component which is referred to generally by Reference Arrow  22 . The front and rear hand truck components  3  and  22  respectively include lower feet or bases  2  and  24 , and have attached upwardly extending handles  4  and  29 . 
     The handle component  4  of the front hand truck  3  is preferably fixedly attached to a proximal end of such hand truck&#39;s base  2 . Similarly, the handle component  29  of the rearward hand truck  22  is fixedly attached to a proximal end of such hand truck&#39;s base  24 . Handle  4  preferably comprises lower and upper segments  6  and  8  which are interconnected by a releasable joint  10 , the handle having an upper “T” bar  12  for two handed forward propulsion of the saw. The handle component  29  of the rear hand truck  22  is suitably configured as an inverted “U”, such handle having right and left uprights  27  and  28 , and having an upper hand grip loop  30  which interconnects upper ends of such uprights. 
     Referring to  FIGS. 1, 2, and 5 , a front plurality of wheels  32  and  34  is fixedly and rotatably mounted to base  2 , such wheels extending downwardly therefrom. In a preferred embodiment, laterally paired wheels  32  are fixedly and rotatably mounted to the under surface of the proximal end of the base  2 . A rear plurality of wheels  36  and  40  is similarly fixedly and rotatably attached to the rear hand truck&#39;s base  24 , such wheels similarly extending downwardly. Wheels  40  are preferably caster wheels which are fixedly attached to the distal end of base  24 . While laterally paired distal caster wheels  40  are preferred, a single centrally positioned caster wheel (not depicted within views) may be suitably alternatively utilized. Proximal wheels  36  may be fixed wheels or caster wheels. 
     A motor and rotatable cutting wheel or blade combination incorporating, referring to  FIG. 2 , a motor  44  and a blade or cutting wheel  46  is preferably fixedly mounted to and supported upon the front hand truck&#39;s base  2 . Suitably, the motor component of such combination may comprise an electric motor. However, such motor component preferably comprises a gas powered internal combustion engine. In the preferred motor and cutting wheel combination, a throttle control lever  14  is in fluid communication with the engine  44  to allow an operator to conveniently adjust motor rotation speed. The rotary output of the engine  44  turns a centrifugal clutch  55  which, upon frictional engagement, turns a drive pulley  48 . Such pulley  48  cyclically drives belt  50  which rotates a driven pulley (not shown in views). The cutting wheel or blade  46  co-rotates with such driven pulley, the cutting wheel  46  being supported for rotation within a vacuum housing  68 . In a preferred embodiment, the vacuum housing  68  enshrouds the upper end of the cutting wheel  46 , such wheel having its cutting depth controlled by vertical slide shafts  72 . Left and right slide plates  70  mounted to the left and right walls of the housing  68  allow the lower edges of said walls to effective abut the slab surface for a variable range of cutting depths. 
     In the preferred embodiment, the cutting wheel enshrouding vacuum housing  68  has a vacuum port  76  which communicates with the interior of the housing  68 . As indicated above, said port preferably resides at an upper and forward position in order to open the housing at a point which coincides with the direction dust and cuttings are thrown by the blade  46 . Referring to  FIG. 4 , as teeth at the front aspect of the blade  46  upwardly emerge from slot  106  during cutting of the slot, such teeth tend to throw concrete dust and cuttings directly upwardly within the housing  68 . Placement of vacuum port  76  at such forward and overlying position to coincide with the direction of travel of such cuttings improves vacuuming efficiency of the assembly. 
     A further structural component of the instant inventive concrete saw comprises a motor powered vacuum which is referred to generally by Reference Arrow  52 . As depicted in  FIG. 1 , the motor powered vacuum  52  is fixedly attached to and is supported by the handle component  29  of the rear hand truck  22 , such attachment being effected by upper and lower canister encircling attachment brackets or bands  56  and  57 . Suitably, the motor powered vacuum  52  may be alternatively supported by attachment brackets (not depicted in views) which extend upwardly from the hand truck&#39;s base  24 . 
     In a preferred embodiment, the motor powered vacuum  52  comprises an electric motor  60  which drives a centrifugal impeller which rotates within an impeller housing  64 . An onboard rechargeable battery  66  is preferably provided for electrically powering the motor  60 , and an on/off switch  67  is provided. High air pressure exhaust driven by the motor  60  out of exhaust port  62  induces low vacuum pressure within an underlying cyclonic canister  54 , such canister being opened by a vacuum port  77 . As indicated in  FIGS. 1 and 3 , the vacuum port  77  is preferably configured as a tubular sleeve which attaches to and communicates with the cylindrical wall of the cyclonic canister  54 . In the preferred embodiment such sleeve port  77  is preferably canted at an angle with respect to such canister wall so dust particles entering the canister are immediately moved in a circumferential direction within the canister. The upper and forward positioning of the vacuum housing&#39;s port  76  and the circumferential canting of port  77  work together to improve and enhance vacuuming efficiency. The motor, the impeller housing  64 , and the battery  66  are preferably supported upon a canister lid  58  which is releasably latched to and covers the upper opening of the cyclonic canister  54 . 
     A vacuum tube  74  has a suction end  75  which is fixedly mounted in communication with the vacuum port  76  of the vacuum housing  68 . A vacuum dispensing end  78  of such hose  74  attaches to the cyclonic canister&#39;s vacuum port  77  by means of a releasable latch  80 . 
     The cyclonic canister  54  preferably incorporates an internal dust filter (not depicted within views) which assures dust free exhaust at port  62 , and a downwardly opening lower end  98  of the cyclonic canister  54  communicates with an upper opening of a flexible dust collection bag  100 . A body of concrete dust  102  contained within the dust collection bag  100  may advantageously rest upon and be supported by a load bearing surface  26  of the base component  24  of the rear hand truck  22 . 
     A trailering latch is preferably provided for interconnecting, and preferably releasably interconnecting the front and rear hand trucks  3  and  22 . The invention&#39;s trailering latch component preferably arranges the front and rear hand trucks so that forward propulsion of the front hand truck  3  simultaneously forwardly pulls the rear hand truck  22 . As indicated in  FIG. 4 , forward propulsion applied by the hands of an operator  108  to the “T” bar  12  of the front hand truck&#39;s handle  4  forwardly drives the front hand truck  3  and all of its attached components. Such forward propulsion, by virtue of the trailering latch, forwardly pulls the rear hand truck  22 , along with its attached components. 
     In a preferred embodiment of the instant invention&#39;s trailering latch component, right and left attachment brackets  82   r  and  82   l  are fixedly attached to and forwardly extend from the proximal end of the rear hand truck&#39;s base  24 . Forward ends of such brackets  82   r  and  82   l  suitably present downwardly opening “U” slots  86   r  and  86   l , such slots respectively releasably engaging rightwardly and leftwardly extending pins  94   r  and  94   l  as depicted in  FIGS. 5 and 6 . In such embodiment, the gas powered motor  44  is encased within and protected by a tubular metal frame  96 , such frame providing advantageous right and left anchoring points for mounting support of the right and left pins  94   r  and  94   l . The depicted trailering latch  82   r , 86   r , 94   r , 82   l , 94   l , 86   l  is intended as being representative of other commonly known releasable latching fasteners (eg. hook and eye fasteners, “T” slot and “T” bar fasteners, screw attached fasteners, etc. Not depicted within views) which may suitably be alternatively utilized for releasably interconnecting structures such as the front and rear hand trucks  3  and  22 . 
     As indicated in  FIG. 4 , the trailering facilitating releasable latch components are preferably vertically upwardly positioned upon the protective frame  96  at an elevation which raises the proximal wheels  36  of the rear hand truck&#39;s base  24  slightly above the slab surface  104 , such wheel elevation advantageously producing, as indicated in  FIG. 2 , a clearance gap  37 . Upon raising the proximal wheels  36  above the slab surface  104 , the preferred caster wheel character of the rear hand truck&#39;s distal wheels  40  advantageously rollably supports the distal end of the rear hand truck  22  while avoiding any resistance to horizontal turning of the front hand truck  3 . 
     The vacuum housing  68  and its interior cutting wheel  46  are supported and operatively extended laterally from the base  2  of the front hand truck, such lateral positioning being depicted, for example, as a rightward cutting assembly extension. The instant inventive concrete saw  1  preferably correspondingly laterally, or, for example, rightwardly positions the handle  4  of the front hand truck component, such corresponding lateral positioning being accomplished by means of an oppositely laterally extending mounting plate  20  whose oppositely lateral end is fixedly attached to a base mount bracket  18 . The lateral positioning of the handle  4  allows a forward propulsion force applied to “T” bar  12  to advantageously align with the cutting wheel  46 . Such lateral positioning of the handle  4  requires that the rearward hand truck  22  including its attached components reside oppositely laterally from the handle  4 . 
     Referring to  FIGS. 2 and 4 , in operation of the instant inventive saw  1 , the operator  108  may grasp “T” bar  12 . Such operator may manually control motor speed via lever  14 . Upon motor driven rotary actuation of the cutting wheel  46 , the operator may manually raise the “T” bar  12 , causing the forward hand truck&#39;s base  2 , vacuum housing  68 , and cutting wheel  46  to pivot downwardly toward the upper slab surface  104 . During such pivoting action, the trailering latch  82   r , 86   r , 94   r ,  82   l , 86   l , 94   l , advantageously functions as a rotary pivot joint. 
     Upon contact of the cutting wheel or blade  46  with the upper slab surface  104 , such wheel commences to cut a concrete slab relief slot  106 . Simultaneous operation of the motor powered vacuum  52  evacuates air within the interior of the housing  68 , drawing silica concrete dust and cuttings upwardly along the vacuum tube  74 . Such cuttings enter the cyclonic canister  54  via vacuum port  77 , and circulating air flow within the canister  54  directs the dust and cuttings downwardly toward the canister&#39;s lower opening  98 . Cuttings and dust within the cyclonic canister fall downwardly into collection bag  100 . With the trailing latches engaged, the rear hand truck  22  moves forwardly simultaneously with the cutting motion of the front hand truck  3 . 
     Upon filling of bag  100  with concrete dust  102 , the operator  108  may deactivate the vacuum  52  by manipulating on/off switch  67 , and by setting the motor  44  to idle. Thereafter, the operator may easily and conveniently disengage the upper opening of the bag  100  from the lower opening  98  of the cyclonic canister  54 . Thereafter the operator may close the bag  100  with a tie to contain the silica dust  102 , and remove the bag to a disposal location. 
     Upon completion of slab cutting and slotting operations, the operator  108  may disconnect the may release latch  80  to disconnect the vacuum tube  74  from the cyclonic canister  54 . Thereafter, the operator  108  may manually raise the proximal or handle end of the rear hand truck  22 , disengaging the trailing releasable latch. Thereafter, the rear hand truck  22  may rest upon its wheels separate from the front hand truck. Thereafter, the operator may grasp the upper hand grip portion  30  of the rear hand truck&#39;s handle  29 , and may tilt the rear hand truck  22  rearwardly toward the operator in a manner similar to the operation of conventional hand trucks. Thereafter, the rear hand truck  22  and attached vacuum components may be rollably moved to storage or equipment transport location. Thereafter, the forward hand truck  3  along with its attached components may be similarly rollably moved. Reversals of the steps described above allow the inventive concrete saw to be reconfigured for recommencement of concrete slab cutting. 
     While the principles of the invention have been made clear in the above illustrative embodiment, those skilled in the art may make modifications to 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 that the invention be given a scope commensurate with the appended claims.