Patent Publication Number: US-10321754-B1

Title: Self-propelled substrate finishing tool

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims the benefit of U.S. Provisional Application No. 62/441,628 filed Jan. 3, 2017 which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     This invention relates to a substrate finishing tool, and more specifically, this invention relates to a self-propelled substrate finishing tool for striating freshly placed substrate. 
     BACKGROUND INFORMATION 
     Concrete is used for a multitude of different applications including the formation of substantially horizontal, hard surfaces commonly referred to as flatwork. The concrete is initially formed into a pourable and workable substance comprising cement, rock aggregate, water, and other additives. The concrete is then poured into forms or other containing structures where it hardens, or “cures”. As the concrete begins to harden, it is generally worked with trowels, troweling machines or various other instruments in order to obtain a relative uniform, non-wavy, durable surface. As a result of such activity, the surface of the concrete may obtain a relatively smooth texture, which can be dangerous for some applications—such as sidewalks, driveways, highways, and the like—particularly when the surface is damp, frosty or icy. 
     To minimize such dangers, the concrete is given a roughened surface as it is hardening, sometimes referred to as a “broom” finish. Such roughening is sometimes accomplished by pushing or dragging the bristles of a broom across the surface of the hardening concrete in a direction generally perpendicular to the anticipated flow of traffic on that surface. As a result, the surface is scored with randomly spaced bristle marks, which marks harden in the surface of the concrete thereby providing a surface which minimizes tendencies for slipping. 
     The degree of scoring for a particular surface generally depends on the anticipated use of that surface. Sidewalks and patios, which are primarily exposed only to foot traffic, for example, need only light or fine scoring to provide a slip-resistant surface. On the other hand, highways, streets, parking lots and bridges, which are primarily subjected to vehicular traffic as opposed to foot traffic, generally require much coarser scoring in order to provide a slip-resistant surface for the vehicles traveling therealong. 
     It is well known to use a garage-type push broom or brush to roughen or score the surface of concrete. Such brushes typically have a width of two feet, or less. Some prior art brushes specially manufactured for finishing concrete have widths of 24, 36 or 48 inches. The bristles thereof, which are generally constructed of polypropylene, horsehair, or nylon, are generally staple set or otherwise formed into channel style strips in a wooden head such that the bristles extend generally perpendicularly downwardly from the wooden head. Another problem with the wooden heads of prior art brushes is the relatively rapid deterioration of the wooden heads due to exposure thereof with the corrosive constituents of the concrete material. 
     To maneuver the brush over the surface of the wet concrete, the brush head is generally attached to the end of a long handle having a sufficient number of sections attached end-to-end such that a user can reach either entirely across the flatwork or at least half-way across, depending on the width of the flatwork. The user then places the bristles of the brush against the flatwork at the side of the flatwork nearest the user and uses the handle to push the brush in a straight line to the side of the flatwork opposite from the user (or slightly beyond midway as the case may be). 
     Then, using the handle as a lever, the user lifts the brush clear of the flatwork and maneuvers the brush to a new position on the flatwork immediately adjacent to that from which the brush was lifted. In fact, the brush is spaced such that the return path to be swept by the brush slightly overlaps the previous path in order to avoid leaving an unroughened strip of concrete between the adjacent sweeps. The handle is then used to pull the brush back to the side of the flatwork nearest the user. The described process is repeated until either the entire surface, or half of the surface nearest the user, is “broomed”. If only half of the surface is reachable by the long handle, the user then proceeds to the opposite side of the flatwork to broom the remaining half of the flatwork. 
     Depending on the length of the handle, a considerable torque or moment must sometimes be applied by the user to lift the brush from the concrete, particularly since the brush becomes gradually heavier due to the concrete that accumulates in and on the brush during use. Additional responsibility is placed on the user to avoid allowing the brush to drop back against or bump the surface of the concrete as the bristles are directed substantially perpendicularly to the surface and can easily gouge concrete material from the surface. 
     Another complication arising from the use of a prior art concrete finishing brush is the long handle, while limits the user&#39;s ability to use it in congested or crowded quarters, such as inside a building or near surrounding structures, due to interference with the necessary path of the long handle during the pulling and pushing procedure inherent in concrete finishing with a brush having a long handle. 
     The channel strip-type brushes used in prior art devices have essentially no gaps between the bristles, just one straight row of continuous bristle fill. As a result, such channel strip-type brushes tend to pull or squeegee the “cream” from the surface of the flatwork concrete. In an attempt to avoid this undesirable effect, some prior art concrete finishing brushes have been constructed with staple set-type bristles which pull or squeegee less “cream” than channel strip-type brushes due to a multiple-row configuration of the bristles, wherein each row has a plurality of equally spaced gaps between clusters of bristles, with the gaps of a consecutive row(s) staggered to fill the gaps of the adjacent row(s). 
     Factors affecting the roughness of the broomed finish include, among other things, the stiffness of the bristles, the angular orientation of the bristles at their point of contact with the flatwork, the softness or “green”-ness of the concrete at the time the roughening finish is applied, etc. As the bristles of most of the prior art brushes are generally approximately perpendicular to the surface of the flatwork, the brush must not be applied too quickly after the “pour”, such as when the concrete has just been “floated” and is very soft and creamy. Otherwise, the tips of the bristles will gouge too deeply into the concrete surface or will scrape off the “creamy” surface and expose the aggregate, or both. As a result, brooming of the flatwork concrete with prior art concrete finishing brushes is generally delayed until the concrete begins to “set” whereby it can more readily endure the abusiveness to the flatwork arising from contact with brushes having bristles oriented substantially perpendicularly to the flatwork. 
     Many times during such delay of using a prior art finishing device, a user may get distracted and not realize that the concrete has hardened more than intended; in other words, the user has waited too long and the concrete has “set” or hardened to the point that the weight of the brush is more easily supported by the green flatwork. Even though some roughening may still be possible, the extent thereof may be substantially less than that desired in order to obtain a slip-resistant surface. Under those circumstances, the user sometimes attempts to enhance the effect of the brooming procedure by tying weights to the brush. Such remedial measure may not provide a practical solution, however, particularly if the user must lift that extra weight at the end of a long handle for the return sweep. In addition, the added weight may cause the surface to become more uneven as some portions of the surface may have cured slightly earlier than other portions of that surface. 
     An improvement was previously made and disclosed in U.S. Pat. No. 5,549,413, which is directed to a concrete finishing tool that substantially uses the sides of the bristles instead of the ends of the bristles for “brooming” flatwork concrete, that does not require the use of a long handle, that can be used to “broom” the entire width of flatwork even though the flatwork may have virtually unlimited width, that can be used to easily sweep strips having widths substantially greater than four feet, that can be used to uniformly and reliably “broom” a flatwork surface shortly after the concrete is poured thereby avoiding the risk of delaying too long before brooming, that avoids the costs of personnel who might not otherwise be overly productive while waiting for the flatwork to partially set as required by prior art concrete finishing devices, that can be used in congested spaces, and that can be quickly disassembled for use with either a push-pin handle or a screw-on handle in a conventional manner while preserving the ability to broom concrete substantially with the sides of the bristles as opposed to the ends of the bristles. 
     Even this improvement requires substantial effort on the part of the operators. Accordingly, there is a need for an improved substrate finishing tool that requires less effort to operate and a more consistent application. 
     SUMMARY 
     In accordance with one aspect of the present invention, a substrate finishing apparatus is provided. The apparatus comprises of a sled for finishing a substrate. A displacement apparatus is attachable to the sled for moving the sled relative to the substrate. A tracking line is engagable by the displacement apparatus to provide a path of travel for the sled such that the sled moves along the tracking line across the substrate. 
     More specifically, the displacement apparatus can comprise of a first sensor activatable by the tracking line and a second sensor activatable by the tracking line. A frictional wheel can engage the tracking line to drive the sled across the substrate. The first sensor and the second sensor are on opposite sides of the frictional wheel, and a tracking line guide positions the tracking line with respect to the frictional wheel. The first sensor and the second sensor can each be a limit switch with an activation lever that moves between an open state and a closed state. The activation lever of each of the first sensor and the second sensor can be combined to a guide tube to direct the tracking line. 
     In operation, when a first end of the tracking line is pulled taut the activation lever of the first sensor moves to a closed state, and when a second end of the tracking line is pulled taut the activation lever of the second sensor moves to a closed state. When the first sensor and the second sensor are each in a closed state, the frictional wheel rotates to move the sled across the substrate. The frictional wheel can comprise a plurality of pointed protrusions to pierce the tracking line during rotation. A reverse switch can be provided to switch a rotational direction of the frictional wheel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a multi-purpose substrate finishing apparatus, according to the present invention. 
         FIG. 2  is an enlarged and fragmentary, side elevational view of the multi-purpose substrate finishing apparatus, showing a selected angular orientation automatically assumed by brushes thereof as the apparatus is being pulled to the right. 
         FIG. 3  is a fragmentary, plan view of the multi-purpose substrate finishing apparatus. 
         FIG. 4  is an enlarged and fragmentary, side elevational view of the multi-purpose substrate finishing apparatus, similar to  FIG. 2  but showing the angular orientation automatically assumed by the brushes as the apparatus is being pulled to the left. 
         FIG. 5  is an enlarged and fragmentary, side elevational view of the multi-purpose substrate finishing apparatus, similar to  FIG. 4  but showing a different selected angular orientation assumed by the brushes as the apparatus is being pulled to the right. 
         FIG. 6  is a further enlarged and fragmentary, side elevational view of the multi-purpose substrate finishing apparatus, showing a portion cut away to reveal details thereof. 
         FIG. 7  is a yet further enlarged and fragmentary, end elevational view of the multi-purpose substrate finishing apparatus, showing details of a block thereof. 
         FIG. 8  is a further enlarged and fragmentary, side elevational view of the multi-purpose substrate finishing apparatus, taken along line  8 - 8  of  FIG. 3 , showing the block being removed. 
         FIG. 9  is a close up view of the displacement apparatus with the tracking line loose. 
         FIG. 10  is a close up view of the displacement apparatus with the tracking line pulled taut. 
         FIG. 11  is an electrical schematic of the operating circuitry for the displacement apparatus. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. 
     The substrate finishing apparatus  1 , as shown in  FIGS. 1 through 11 , comprises a sled  100  with a texturing apparatus  3  for texturing or roughening the surface of freshly poured substrate flatwork  5 , mounting apparatus  7  for mounting the texturing apparatus  3  and a control apparatus  9  for controlling the texturing apparatus  3 . Sled  100  can be configured for self-propulsion by a displacement apparatus  11  for moving the sled  100  relative to the flatwork  5 . Sled  100  can be of any type and any configuration useful for applying different types of texture of finish to flatwork  5 . An exemplary sled  100  is disclosed in U.S. Pat. No. 5,549,413, the content of which are incorporated herein by reference. 
     The texturing apparatus  3  of sled  100  generally includes a pair of brush assemblies  13  and  15 , each with a head  17 , a bristle block  19  and bristles  21 . Preferably, the heads  17  are constructed of lightweight material, such as extruded aluminum or other suitable material, which is acceptably durable when exposed to the corrosive and degrading constituents contained in concrete material. The bristles  21  are constructed of fill  23  with an acceptable bend recovery rate, such as 6/12 nylon or other suitable material. For some applications, the fill  23  is preferably “soft”, such as 0.010″ diameter nylon. For other applications, the fill  23  is preferably “stiff” such as 0.022″ diameter nylon. For yet other applications, the fill  23  has a “medium” stiffness, such as 0.016″ diameter nylon. For ease of identification, each stiffness is preferably color-coded, such as black for “soft”, orange for “medium”, and green for “stiff”. 
     Each of the blocks  19 , which is constructed of High Density Polyethylene (“HDPE”) or other suitable material, has a first set  25  of uniformly and linearly spaced partial bores  27  which are spaced parallel to a second set  29  of uniformly and linearly spaced partial bores  31  in a bottom surface  33  of each of the blocks  19 , as shown in  FIG. 2 . The set  25  is axially offset from the set  29  such that the partial bores  27  are staggered relative to the partial bores  31 . Each of the blocks  19  has a pair of opposing, outwardly directed ridges  35  along an upper surface  37  thereof, as shown in  FIG. 7 . 
     The diameter of each of the bores  27  and  31  and the spacing therebetween is dependent upon the diameter, quantity and length of the fill  23  being used for each bristle cluster  39  of the bristles  21 . For example, the bores  27  and  31  may each have a diameter of approximately 13/64 inch, a center-to-center spacing between adjacent ones of the bores  27  and between adjacent ones of the bores  31  of approximately 5/16 inch, and a center-to-center spacing between the set  25  and the set  29  of approximately 7/16 inch. Each of the bristle clusters  39  is secured to its respective bore  27  or  31  by stapling, or other suitable means. In the preceding example, the bristles  21  may extend approximately 2¼ inches generally perpendicularly outwardly from the respective blocks  19 . 
     The head  17  has a pair of opposing, inwardly directed grooves  41  which are adapted to cooperatively receive the ridges  35  slidingly and longitudinally therethrough, as indicated by the arrow designated by the numeral  43  in  FIG. 8 . The ridges  35  are generally frictionally retained with the grooves  41 . The length of the head  17  is generally co-extensive with the length of the block  19  contained therein. 
     It is to be understood that, for some applications, several of the blocks  19  may be contained within the head  17 , with the blocks  19  having a combined length co-extensive with the length of the head  17 . For example, shorter sections of the blocks  19  normally have lower friction relative to the head  17  and can be more easily removed and reinserted into the grooves  41  than can a single one of the blocks  19  having a length co-extensive with the head  17 . 
     The mounting apparatus  7  generally include a plurality of opposing pairs of brackets  45 , such as the opposing pairs of brackets  45 . Each of the heads  17  generally has an upwardly directed slot  50  with a pair of opposing and inwardly directed grooves  51 , as shown in  FIG. 7 . Each pair of the opposing pairs of brackets  46  are connected to the respective head  17  by bolts and nuts  53  slid lengthwise along the slot  50  as desired and secured in place. 
     Each of the pairs of brackets  46  has as aligned pair of throughbores  55  for slidably receiving a pivot pin  56  therethrough, as shown in  FIG. 6 . The mounting apparatus  7  also include a plurality of spacers  57 , each having a first end  59  a second end  60 , and a lower edge  61 . Each of the spacers  57  generally has one or more throughbores in each of the ends  59  and  60 , such as the throughbores  63  and  64  in the end  59  for slidably receiving the pivot pin  56  therethrough, as shown in  FIGS. 4 through 6 , and the throughbores  66  and  67  in the end  60 , as shown in  FIG. 2 . A keeper  69  retains the pivot pin  56  such that the spacers  57  pivot about axis “A” relative to the brackets  46 , as shown in  FIGS. 2 and 6 . 
     Similarly, the brush assembly  15  is attached to the opposing pairs of brackets  47  by nuts and bolts  71 . Again, each of the opposing pairs of brackets  47  is pivotally connected by a pivot pin  73  inserted through a respective throughbore  66  or  67  in the end  60  and through an aligned pair of throughbores  75  in the brackets  47 , such that the spacers  57  pivot about axis “B” relative to the brackets  47 , as shown in  FIGS. 2 and 8 . 
     The control apparatus  9  include each of the throughbores  63  and  66  being spaced equidistantly from the lower edge  61 , the throughbores  64  and  67  being spaced equidistantly from the lower edge  61 , and the throughbores  55  and  75  being spaced equidistantly from corners  77  and  78 , and from corners  80  and  81 , respectively, as shown in  FIG. 2 . 
     The displacement apparatus  11  is removably mountable to sled  100  to convert a manually maneuvered sled  100  into one operated by self-propulsion. Because displacement apparatus  11  is removable from sled  100 , displacement apparatus is easily cleanable and stored in a clean environment. Also, if displacement apparatus  11  malfunctions, sled  100  can be operated manually in the traditional manner. The user merely removes displacement apparatus  11  and replaces it with another spacer  57  and reconfigures tracking line  130 . Displacement apparatus  11  generally includes a tracking line  130  and a control box  132  housing a motor  134  and operating circuitry  136  necessary to operate motor  134 . Motor  134  drives a frictional wheel  138  which engages tracking line  130  to drive sled  100  along tracking line  130 . 
     As shown in  FIG. 11 , operating circuitry  136  comprises of a power source  150  that is turned on/off by a power switch  152  with its state indicated by a power indicator light  153 . A low voltage sensor  155  senses when power source  150  is low on power and activates a low voltage alarm  156 , such as a buzzer or light, to warn the operator of the same. A first sensor  144  and a second sensor  146  are positioned electrically-between power source  150  and motor  134  to control the operation of motor  134 . A directional switch  158  can be positioned electrically-between second sensor  146  and motor  134  to switch a rotational direction of motor  134 . 
     Turning to  FIGS. 9-10 , first sensor  144  and second sensor  146  are positioned on opposite sides of control box  132  for sensing an on command to initiate engagement by frictional wheel  138  of tracking line  130 . The on command to initiate engagement by frictional wheel  138  of tracking line  130  can be when tracking line  130  is pulled taut by user  92  and user  93 . In an embodiment, first sensor  144  and second sensor  146  are each limit switches with an activation lever  148 . First sensor  144  and second sensor  146  can be any type of sensors, for example, motion sensors, tension sensors, strain gauges, image recognitions sensors (e.g. a camera) with image recognition software, etc. In embodiments where first sensor  144  and second sensor  146  use image recognition sensors, sled  100  can traverses across substrate flatwork  5  to the respective ends of substrate flatwork  5 . In such embodiments, the on command to initiate engagement by frictional wheel  138  of tracking line  130  can be when the image recognition sensors sense substrate flatwork  5  in front of sled  100 . 
     First sensor  144  and second sensor  146  are positioned in relative proximity to tracking line  130 , so that in a relaxed state, as shown in  FIG. 9 , tracking line  130  is loose and the first sensor  144  and second sensor  146  are both open with the activation lever  148  of each of first sensor  144  and second sensor  146  in an open state. When user  92  and user  93  each pull tracking line  130  taut, as shown in  FIG. 10 , tracking line  130  firms up and moves into position against the activation lever  148  of each of first sensor  144  and second sensor  146  thereby closing each of first sensor  144  and second sensor  146 . Each of first sensor  144  and second sensor  146  must be closed for motor  134  to be powered. This means that if one of the users is not paying attention and is not holding tracking line  130  taut, motor  134  is not engaged and sled  100  won&#39;t move. Finally, each activation lever  148  can further have a guide tube  160  combined thereto, to more precisely locate tracking line  130  and close activation lever  148 . With both of first sensor  144  and second sensor  146  closed, motor  134  is powered and drives a frictional wheel  138 . 
     In operation, user  92  and user  93  each pull their respective ends of tracking line  130  taut. This engages the frictional wheel  138  to move sled  100  across flatwork  5 . Upon completion of the sweep from the side  94  to the side  95 , the user  92  simply picks up the apparatus  1 , such as by one or more of the centrally located ones of the spacers  57 , switches directional switch  158  to reverse the rotational direction of motor  134 , and places the apparatus  1  down on the flatwork  5  at the side  95  such that the next sweep of the apparatus  1  will slightly overlap the sweep that was just completed. Then, user  92  and user  93  each pull their respective ends of tracking line  130  taut to the frictional wheel  138  to move sled  100  across flatwork  5 . It is to be understood that while certain forms of the present invention have been illustrated and described herein, it is not to be limited to the specific forms or arrangement of parts described and shown. 
     Displacement apparatus  11  comprises of a housing or control box  132  to house operating circuitry  136  and frictional wheel  138 . The inside of control box  132  is shown in  FIGS. 9-10 . As show, tracking line  130  enters in one end of control box  132  and out the other end of control box  132 . In between, is the first sensor  144  and second sensor  146 , as previously discussed. Between first sensor  144  and second sensor  146  is the frictional wheel  138 . In an embodiment where tracking line  130  is a nylon rope, it can be advantageous to configure frictional wheels  138  with a plurality of pointed protrusions  164  to pierce tracking line  130  during rotation. This provides a higher frictional engagement without encouraging a higher load on motor  134 . A tracking line guide  154  can positioned on the other side of tracking line  130  from frictional wheel  138  to keep tracking line  130  while it is pressed upon by frictional wheels  138 . 
     While the principles of the invention have been described herein, it is to be understood by those skilled in the art that this description is made only by way of example and not as a limitation as to the scope of the invention. Other embodiments are contemplated within the scope of the present invention in addition to the exemplary embodiments shown and described herein. Modifications and substitutions by one of ordinary skill in the art are considered to be within the scope of the present invention, which is not to be limited except by the following claims.