Patent Document

CROSS-REFERENCED TO RELATED APPLICATIONS 
     Not applicable 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable 
     BACKGROUND OF THE INVENTION 
     I. Field of the Invention 
     The present invention relates to a slat cleaning tool. More specifically, the present invention relates to a tool for cleaning slag and other accumulated debris from the slats of a work piece support table used to support work pieces. 
     II. Related Art 
     Cutting shapes from a work piece such as metal sheets or plates is commonly performed using a beam of energy created by laser or plasma. The work piece is typically supported on a table that consists of narrow, spaced apart slats. Molten material is removed from the cut area or kerf and some is deposited and forms slag on the top and sides of the slats. Slats typically have peaks and valleys which minimizes the possibility of the cut beam contacting the peak and creating a bad mark on the bottom of the work piece. As slag and debris accumulates, an increasing area of the slats contact the bottom of the work piece leading to uneven support which contributes to loss of cut quality and accuracy. The slats therefore need to be replaced or cleaned to eliminate such slag and debris from the support table. Prior art methods and tools used for this purpose have proven to be costly, inefficient and not always effective. Often the slats must be removed from the table for cleaning. There is a real need in the art for a tool which can be employed to quickly and efficiently remove slag from the slats without requiring their removal from the table. 
     SUMMARY OF THE INVENTION 
     A cleaning apparatus for simultaneously cleaning opposing side of the slats (also known as “rails”) of the support table is disclosed. The cleaning apparatus includes a primary frame and first and second cleaning assemblies. Each of the two cleaning assemblies includes a secondary frame pivotally coupled to the primary frame. Mounted to the secondary frame is a gear train. The gear train includes at least a drive gear and a follower gear. One or more idler gears may be interposed between the drive gear and follower gear. Each of the two cleaning assemblies also includes a tool shaft. One end of the tool shaft is coupled to the follower gear. The other end of the tool shaft is coupled to a scraping tool. The scraping tool comprises a plurality of scraping blades. As such, rotation of the follower gear imparts rotation to the scraping tool. The scraping blades may extend in a direction parallel to the axis of rotation of the tool shaft. Alternatively, the scraping blades may extend in a spiral manner about the axis of rotation of the tool shaft. 
     The drive gear of the first cleaning assembly and the drive gear of the second cleaning assembly engage each other. Further, at least one biasing member is provided. The biasing member has a first end coupled to the secondary frame of the first cleaning assembly and a second end coupled to the secondary frame of the second cleaning assembly. This biasing member is adapted to force the scraping tools of the first and second cleaning assemblies into cleaning positions adjacent opposite sides of a rail or slat to be cleaned. The biasing member may be a spring having an end pivotally coupled to the first cleaning assembly and a second end pivotally coupled to the second cleaning assembly. 
     The cleaning apparatus further includes a rotatable drive shaft having a first end coupled to the drive gear of the first cleaning assembly and a second end adapted to be coupled to a motor. The motor rotates the drive shaft which causes the gears of the gear train, the blade shafts and the scraping blades of both the first and second cleaning assemblies to rotate. In some embodiments the blades rotate in opposite directions and impart an upward cleaning action to the opposite sides of the slat or rail being cleaned. 
     The cleaning apparatus further includes a housing surrounding the frame and the first and second cleaning assemblies. The tool shafts project from the housing and the scraping tools are exterior to the housing. The housing is adapted to rest on the slats and hold the scraping tools at about a 20° angle with respect to the longitudinal axis of the slats. Thus, as the tools are rotated, they rotate upwardly along the sides of a slat causing slag residing along the sides and areas between top teeth of the slats to be removed. A pole projecting from the housing may also be provided. This pole is used to guide the cleaning apparatus along the slats. 
     A complete understanding of the invention will be obtained from the following description when read in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view showing a work table for supporting a work piece, the table having a plurality of slats. 
         FIG. 2  is an end view of one of the slats of the worktable of  FIG. 1 . 
         FIG. 3  is a partial side view of a slat having teeth along the top of the slat. 
         FIG. 4  is a rear view of the slat cleaning apparatus of the present invention. 
         FIG. 5  is a front view of the slat cleaning apparatus of  FIG. 3 . 
         FIG. 6  is an end view of the cutting end of the slat cleaning apparatus of  FIG. 3 . 
         FIG. 7  is an end view of the drive end of the slat cleaning apparatus of  FIG. 3 . 
         FIG. 8  is a bottom view of the slat cleaning apparatus of  FIG. 3 . 
         FIG. 9  is a top view of the slat cleaning apparatus of  FIG. 3 . 
         FIG. 10  is a side view of an alternative scraping tool to that shown in  FIG. 3 . 
         FIG. 11  is a perspective view of the cleaning apparatus of  FIG. 3  coupled to an electric motor. 
         FIG. 12  is a side view of the cleaning apparatus housing with a guiding pole extending from the housing and with a slat located between the scraping tools of the cleaning apparatus. 
         FIG. 13  is an end view of the cleaning apparatus housing with a guiding pole extending from the housing and with a slat located between the scraping tools of the cleaning apparatus. 
         FIG. 14  shows an alternative mechanism for coupling a scraping tool of the cleaning apparatus to the tool shaft in cross section. 
     
    
    
     DETAILED DESCRIPTION 
     This description of the preferred embodiment is intended to be read in connection with the accompanying drawings, which are to be considered part of the written description of this invention. In the description, relative terms such as “lower”, “upper”, “horizontal”, “vertical”, “above”, “below”, “up”, “down”, “top”, and “bottom” as well derivatives thereof (e.g., “horizontally”, “downwardly”, “upwardly”, etc.) should be construed to refer to the orientation as then described or as shown in the drawings under discussion. These relative terms are for convenience of the description and do not require that the apparatus be constructed or operated in the orientation shown in the drawings. Further, terms such as “connected”, “connecting”, “attached”, “attaching”, “joined”, and “joining” are used interchangeably and refer to one structure or surface being secured to another structure or surface or integrally fabricated in one piece, unless expressly described otherwise. 
     A worktable for supporting a work piece (not shown) is shown in  FIGS. 1-3 . As illustrated, the worktable includes a table frame  2  which holds and supports a plurality of slats or rails  3 . Each slat  3  is an elongate narrow structure having opposing sides  4  and  5 . The slats  3  run parallel to each other, but are spaced apart. As shown in  FIG. 3 , the slats  3  may be provided with a row of teeth  6  having gaps  7  between the teeth. 
     Worktables of the type shown in  FIGS. 1-3  are often used with laser, plasma and other workstations. Such worktables  1  support the work piece above on top of the slats  3  and below the cutting head of the cutting tool. The slats are relatively thin to prevent the support surface from being damaged by the cutting beam after the item being cut has been perforated. 
     The slats  3  are commonly made of steel. Slag and other debris generated during the cutting operation sticks to the sides  4  and  5  of the slats and in the gaps  7  between teeth  6  formed in the top of the slats  3  making the slats  3  unusable after a very short period of time. While others have tried to address this problem by making slats  3  of materials such as copper to which slag does not readily adhere, this is a very costly solution given the relative price of copper and the steel used when making slats. 
       FIGS. 4-14  show a tool  10  ideally suited for removing slag simultaneously from the opposing side  4  and  5  and gaps  7  between the teeth  6  of a slat  3 . The tool  10  comprises a primary frame  12  and first and second cleaning assemblies  14  and  16 . 
     The primary frame  12  comprises a base plate  20  and two end plates  22  and  24  mounted adjacent or to opposite ends of the base plate  20 . End plate  22  has a first mounting hole  26  and a second mounting hole  28 . Likewise, end plate  24  has a first mounting hole  26 ′ and a second mounting hole  28 ′. When the primary frame  12  is assembled, mounting holes  26  and  26 ′ are axially aligned with each other. Likewise, mounting holes  28  and  28 ′ are axially aligned with each other. The base plate  20  may include one or more access openings  30  such as  30  shown in  FIG. 9 . 
     The two cleaning assemblies  14  and  16  are constructed in a similar fashion, This is perhaps best illustrated in  FIGS. 4 and 5 . Each of cleaning assemblies  14  and  16  include a secondary frame  40 / 40 ′. The secondary frames  40 / 40 ′ include support plates  42 / 42 ′. The secondary frames  40 / 40 ′ also include drive end plates  44 / 44 ′, scraping end plates  46 / 46 ′ and intermediate plates  48 / 48 ′ extending from the support plates  42 / 42 ′ in the same direction and in a generally parallel manner. 
     Each of the two cleaning assemblies  14  and  16  also includes a gear train  50 / 50 ′. The gear trains  50 / 50 ′ are mounted to and between the drive end plates  44 / 44 ′ and the intermediate plates  48 / 48 ′. More specifically, each gear train  50 / 50 ′ includes a drive gear  52 / 52 ′ and a follower gear  54 / 54 ′. The gear trains  50 / 50 ′ may also include one or more idler gears such as idler gear  56 / 56 ′. 
     Drive gear  52  is mounted to and journaled for rotation with a drive shaft  60 . The drive shaft  60  extends through axially aligned holes in the drive end plate  44 , the scraping end plate  46  and the intermediate plate  48  of the secondary frame  40 . The drive shaft  60  also extends through the mounting hole  26  in the first end plate  22  and the mounting hole  28  in the second end plate  24  of the primary frame  12  to pivotally couple the secondary frame  40  to the primary frame  12  between the end plates  22  and  24  of the primary frame  12 . Drive shaft  60  may be provided with a shank  61  extending outwardly from the first end plate  22 . Shank  61  permits the drive shaft  60  to be coupled to a motor  100 . The motor  100  may be the motor of a rotary device such as a drill as shown in  FIG. 11 . The motor most typically be a motor dedicated to the tool  10  housed in the tool&#39;s housing  200  shown in  FIGS. 12 and 13 . In either case, the motor rotates the drive shaft  60 . 
     Drive gear  52 ′ is mounted to and journaled for rotation with a pseudo drive shaft  60 ′. The pseudo drive shaft  60 ′ extends through axially aligned holes in the drive end plate  44 ′, the scraping end plate  46 ′ and the intermediate plate  48 ′ of the secondary frame  40 ′. The pseudo drive shaft  60 ′ also extends through the mounting hole  26 ′ in the first end plate  22  and the mounting hole  28 ′ in the second end plate  24  of the primary frame  12  to pivotally couple the secondary frame  40 ′ to the primary frame  12  between the end plates  22  and  24  of the primary frame  12 . Pseudo drive shaft  60 ′ does not, however, include a shank or any other direct driving connection to the motor  100  because the drive gear  52  of the first cleaning assembly  14  engages (i.e., meshes with) the drive gear  52 ′ of the second cleaning assembly  16  such that rotation of the drive gear  52  by the shank  61  and motor  100 / 200  also causes gear  52 ′ to turn. 
     The follower gears  54 / 54 ′ are mounted to and journaled for rotation with a tool shaft  62 / 62 ′. Each tool shaft  62 / 62 ′ extends through axially aligned holes in the drive end plate  44 / 44 ′, the scraping end plate  46 / 46 ′ and the intermediate plate  48 / 48 ′ of the secondary frame  40 / 40 ′. The tool shaft  62 / 62 ′ also includes a scraping tool mounting section  64 / 64 ′ which extends past the scraping end plate  46 / 46 ′. 
     While the components may be arranged so that the drive gear  52 / 52 ′ directly drives the follower gear  54 / 54 ′, the embodiment shown in the drawings include idler gears  56 / 56 ′. An idler gear shaft  66 / 66 ′ is used to couple the idler gears  56 / 56 ′ to the drive end plate  44 / 44 ′ and intermediate plate  48 / 48 ′. As showed, the drive gears  52 / 52 ′, idler gears  56 / 56 ′, and follower gears  54 / 54 ′ are arranged such that as rotation is imparted by motor  100  to the drive shaft  60 , all of the gears turn and rotational motion is also imparted to each of the blade shafts  62 / 62 ′. 
     Various scraping tools  70 / 70 ′ may be secured to the scraping tool mounting sections  64 / 64 ′ of the tool shafts  62 / 62 ′. One type of scraping tool is shown in  FIGS. 4-9 and 11-13 . The scraping tools  70 / 70 ′ have a hollow core  71 / 71 ′ and a plurality of scraping blades  76 / 76 ′. The hollow core is internally keyed to the shape of the scraping tool mounting section  64 / 64 ′ so that the scraping tools  70 / 70 ′ spin with the tool shafts  62 / 62 ′. The scraping tool mounting sections  64 / 64 ′ also have a threaded portion. Nuts  74 / 74 ′ are used to fix the scraping tools  70 / 70 ′ to the scraping head mounting sections  64 / 64 ′. Alternatively, and as shown in  FIG. 14 , the tool shafts  62 / 62 ′ may be provided with a threaded bore  300  extending inwardly from the end. The tools  70 / 70 ′ may include a longitudinal center bore  302  divided into two sections  304  and $ 06  by a shoulder  308 . This arrangement allows the tools  70 / 70 ′ to be slid over the tool shafts  62 / 62 ′ and a bolt  310  having threads  312  adapted to mesh with those of the threaded bore  300  and a head  314  to be used to secure the tools  70 / 70 ′ in place over the shafts  62 / 62 ′ such that the tools rotate with the shaft. The bolt  310  is tightened using a tool such as a screw driver, Allen wrench, socket wrench or the like and the head  314  is adapted to be tightened and loosened with the tool of choice. The head  314  of bolt  310  firmly engages the shoulder  308  of the tools  70 / 70 ′ when tightened. As noted above, the scraping tools  70 / 70 ′ also includes a plurality of scraping blades  76  and  76 ′ extending from the cores  71 / 71 ′. The scraping blades are elongate and extend in a direction parallel to the axis of rotation of the tool shafts  62 / 62 ′. 
     An alternate scraping head  80  is shown in  FIG. 10 , The primary difference is that the blades  82  extend from the core  71  in a spiral manner about the axis of rotation of the tool shafts  62 / 62 ′. 
     As best shown in  FIG. 9 , and visible through the access opening  30  in base plate  20  of the primary frame  12 , are a pair of biasing members  90 . Each biasing member  90  is a spring  92  having a first end  93  pivotally coupled to the support plate  42  of secondary frame  40  of the cleaning assembly  14  and a second end  94  pivotally coupled to the support plate  42 ′ of the secondary frame  40 ′ of the second cleaning assembly  16 . The biasing members  90  force the scraping heads  70 / 70 ′ toward each other and into cleaning positions. The scraping heads  70 / 70 ′ are in their respective cleaning positions there is a gap between them sufficient to receive a slat  3  to be cleaned. As such, the scraping heads are adapted to clean the opposite sides  4  and  5  of a rail  3 . 
     More specifically, the biasing members  90  pivot the first cleaning assembly  14  about drive shaft  60  and the second cleaning assembly  16  about pseudo drive shaft  60 ′ until scraping blades from the scraping tools  70 / 70 ′ contact the opposite sides  4  and  5  of a slat  3   
     The cleaning apparatus  10  typically includes a housing  200  as shown in  FIGS. 12 and 13 . The housing  200  may be provided with a first compartment  202  which encloses a motor (not shown) and a second compartment  204  which encloses the primary frame  12  and the majority of the two cleaning assemblies  14  and  16 . An elongated handle  210  extends from the housing. The housing has openings which permit the scraping tool mounting sections  64 / 64 ′ of the tool shafts  62 / 62 ′ to project from the housing  200 . The scraping tools  70 / 70 ′ thus also reside outside of the housing  200 . As illustrated, the housing  200  has a bottom surface  206  which is adapted to rest on the slats  3  of the worktable such that the tools  70 / 70 ′ are held on opposite sides of a slat  3  at an angle of about 22° with respect to the longitudinal axis of the slat  3 . This angle may be varied within a range of 5° to 45°. This angle causes the tools  70 / 70 ′, as they rotate in the directions shown in  FIG. 13 , to rotate upwardly against the slag on the slats  3  causing the slag, not only along the sides of the slat  3 , but also the slag in the gaps  7  between the teeth  6 , to be scraped off the slat  3 . 
     The operation of tool  10  will now be described. First, the tool  10  is positioned with respect to a slat  3  to be cleaned such that the slat  3  is between the scraping tools  70 / 70 ′ as illustrated in  FIGS. 12 and 13 . As such, one side  4  of the rail  3  is adjacent scraping tool  70  and the other side  5  of rail  3  is adjacent scraping tool  70 ′. The motor  100  is then energized so as to impart rotation to the drive shaft  60 . Drive shaft  60  imparts rotational motion to the drive gear  52 . Drive gear  52  imparts rotational motion to idler gear  56  and to drive gear  52 ′. Idler gear  56  turns follower gear  54  which rotates the tool shaft  62  and, thus, scraping tool  70 . Drive gear  52 ′ turns idler gear  56 ′, tool shaft  62 ′ and scraping tool  70 ′. When viewed as in  FIG. 13 , scraping tool  70  turns in the counterclockwise direction and the scraping tool  70 ′ turns in the clockwise direction. The housing holds the scraping tools  70 / 70 ′ at an angle that causes the tools to scrape upwardly along the sides of the slat  3 . The turning of the scraping tools  70 / 70 ′ causes the blades  76  to engage and remove slag on the first side  4  of slat  3  and blades  76 ′ to engage and remove slag on the second side  5  of slat  3 . The upward scraping action causes slag, to be removed from the gaps  7  between the teeth  6  of the slat  3 . The tool  10  is pushed along the slat  3  using the handle  210  or the handle of the rotary tool motor  100  (depending upon the specific embodiment) to remove the slag from the entire length of the slat  3 . 
     Those skilled in the art will recognize that various modifications and additions may be made without deviating from the invention. By way of example, the idler gears may be eliminated such that the gear trains have only the drive gear and the follower gear. Likewise, additional idler gears may be added. Further, a single biasing member may be used instead of two. Alternatively, more than two biasing members may be employed. The intermediate plate of the secondary frame may be eliminated. The shapes of the blades of the scraping tools may be other than as shown. A housing may be added covering the moving parts of the tool  10  to improve appearance and safety. Likewise, the direction of rotation of the tool shafts and scraping tools may he reversed or otherwise modified so they rotate in the same direction if it is advantageous to do so to accommodate differing cutting head designs. Therefore, the foregoing description is intended to be explanatory and not limiting. 
     More specifically, it is intended that the foregoing detailed description be regarded as illustrative rather than limiting, and that it be understood that it is the following claims, including all equivalents, that are intended to identify the invention.

Technology Category: 7