Patent Publication Number: US-6708686-B2

Title: Power glide tile cutter

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a tile cutter, in particular but not exclusively, a tile cutter for ceramic tiles of the type used for covering walls or floors. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the present invention there is provided a tile cutter comprising a base having a support surface upon which tiles to be cut may be supported, a pair of guide rails mounted upon the base, the guide rails being parallel to one another and being spaced from said support surface to enable a tile to be located between the guide rails and said support surface, a cutter assembly mounted on a carriage, the carriage being movably mounted on said pair of rails so as to guide said cutter assembly along a rectilinear path across said support surface, and said carriage including a first rotary bearing assembly in rotary contact with one rail and a second rotary bearing assembly in rotary contact with the other rail, each rotary bearing assembly including at least one bearing in the form of a roller having a shaft on which is mounted at least one wheel which projects radially beyond said shaft and is axially fixed relative to the shaft, the wheel having an axial face, a circumferential face and a transition face extending between said axial and circumferential faces, said transition face being in rotary contact with said rail. 
    
    
     Various aspects of the present invention are hereinafter described with reference to the accompanying drawings, in which: 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a plan view of a tile cutter according to an embodiment of the invention. 
     FIG. 2 is a side view of the tile cutter shown in FIG.  1 . 
     FIG. 3 is a perspective view of the tile cutter of FIG. 1 shown in a different operating mode. 
     FIG. 4 is a cross-sectional view taken along line IV—IV in FIG.  1 . 
     FIG. 5 is a detail perspective view of part of the tile cutter of FIG.  1 . 
     FIG. 6 is a broken away perspective view of part of the tile cutter of FIG.  1 . 
     FIG. 7 is an end view of the part shown in FIG.  6 . 
     FIG. 8 is a section along lines VIII—VIII in FIG.  6 . 
    
    
     DETAILED DESCRIPTION 
     The tile cutter  10  according to a preferred embodiment of the present invention includes a base  20  which has an upper planar support surface  21  upon which tiles to be cut are placed. 
     A pair of guide rails  30  are mounted on the base  20  by a pair of bosses  22  into which opposed ends of the rails  30  are received. 
     The rails  30  are mounted so as to be parallel to one another and also parallel with the planar support surface  21 . 
     The base  20  is preferably a plastics moulding and the bosses  22  are preferably also formed from plastics material and are preferably integrally moulded with the base  20 . 
     This enables the position of the rails to be accurately and consistently reproduced for mass production. 
     Preferably the rails  30  are round in cross-section, preferably circular, and are preferably tubular. The rails  30  are preferably made form stainless steel so as to be resistive to corrosion and abrasive wear. 
     Alternatively, the rails  30  are polygonal in section. 
     Located on the guide rails  30  is a cutter carriage  40 . 
     The cutter carriage  40  includes a carriage body  41  on which a cutter assembly  50  is mounted. 
     The cutter assembly  50  includes a cutter wheel  52  rotatably mounted on one end of a lever  53  which is pivotally mounted on the carriage body  41  via a pivotal connection. The opposite end of the lever  53  extends longitudinally of the rails  30  to define a handle  54 . 
     Preferably the pivotal connection is located centrally of the carriage body  41  so as to position the cutter assembly  50  centrally between the rails  30 . 
     The cutter wheel  52  has an axis of rotation perpendicular to the axis of the rails  30  so that movement of the carriage body  41  along the rails  30  causes the cutter wheel  52  to move along a rectilinear path in which the wheel  52  is maintained perpendicular to the base  20 . 
     Preferably an elongate ridge  60  is provided on the base  20  which extends along the rectilinear path such that the wheel  52  is opposed to the ridge  60  during its travel along rails  30 . Thus in use, when a tile is placed upon the base  20 , it is supported upon ridge  60  and downward pressure applied by the cutter wheel  52  to score the tile as it travels along the rails  30  is opposed by the ridge  60 . 
     Preferably the ridge  60  comprises a channel formation  62  integrally moulded with the base  20  and a rod  63  of a rigid wear resistant material mounted within the channel formation  62 . Moulding the channel formation  62  integrally with the base  20  enables the ridge  60  to be accurately and consistently reproduced relative to the position of the rails  30  and cutter assembly  50  for mass production. 
     Insertion of a separate rod  63  enables a rod of a suitable material to be chosen, preferably the rod  63  is a solid rod of a suitable steel. After scoring of the tile, the rod  63  acts as a breaker bar for snapping the tile along a score line created by the cutter. 
     To enable snapping of the tile to be achieved, the lever  50  is preferably provided with a pressure foot  56  located on the opposite side of the lever&#39;s pivotal connection such that downward movement of the lever  50  enables the foot  56  to be brought into contact with the tile and for downward pressure to be applied thereto through foot  56 . 
     Preferably the base  20  is provided with a raised land portion  70  which defines as tile positioning shoulder  71 . The shoulder  71  extends in a rectilinear manner across the width of base  20  at an angle of 90° to the longitudinal axis of rails  30 . 
     This enables a tile to be placed upon the base  20  with one side in abutment with the shoulder  71  and so accurately position the tile such that the cutter wheel  52  is able to score a break line at 90° to the side of the tile in abutment with shoulder  71 . 
     Preferably a tile support arm  80  is provided which is movable from a stowed position (FIGS. 1 and 2) to an extended position (FIG. 3) whereat it projects beyond one side of the base  20  to provide added support for a tile being cut, in particular a large tile e.g. 18 inch square tile and also provide an extension to shoulder  71 . 
     Preferably the tile support arm  80  is movably mounted relative to the base  20  by a pivotal connection  83  to enable it to move between its stowed position (FIG. 1) whereat it is located within the boundaries of the base  20 , to an extended position (as seen in FIG. 3) whereat it projects beyond a side of the base  20 . 
     Preferably an adjustable mitre guide  90  is provided to enable a tile to be positioned at a desired angle relative to the rectilinear path of travel of the cutter wheel  52 . 
     Preferably the mitre guide  90  has an elongate support arm  91  which in slidingly received in a groove  92  formed in the land portion  70 . A releasable clamp  93  is provided for preventing axial movement of the arm  91  in groove  92 . 
     A tile mitre guide arm  94  is mounted on the support arm  91  via a bracket  95 . The bracket  95  is fixedly mounted on the support arm  91  whilst the mitre guide arm  94  is pivotally mounted on the bracket  95  via a releasable pivot clamp  96  which is preferably defined by a bolt and a hand nut. The mitre guide arm  94  has a rectilinear side wall  97  against which a side of a tile may abut when seated upon the base  20 . 
     Adjustment of the angular position of arm  94  relative to the rectilinear path of travel of cutter wheel  52  is achieved by release of the pivot clamp  96 , rotation of the arm  94  relative to bracket  95  and re-clamping of the pivot clamp  96 . 
     The bracket  95  is arranged so as to be movable over the land portion  70  and thereby enable the mitre guide arm  94  to be moved close to the rectilinear path of the cutter wheel. 
     A common requirement in tile cutting is to cut a tile diagonally from corner to corner. 
     Preferably the tile cutter  10  of the present invention includes an adjustable clamping jaw  100  mounted on base  20  for clamping a tile to be cut such that opposed corners of the tile are positively located along the rectilinear path of travel of the cutter wheel  52 . 
     As shown in FIGS. 1 and 5, the clamping jaw  100  includes a jaw body  101  having a V-shaped recess  102  for recessing a corner  103  of a tile. 
     The body  101  is slidably located in a pair of guide grooves  106  formed in the base  20  for movement along the rectilinear path of the cutter wheel. The shoulder  71  of land portion  70  has a V-shaped recess for receiving an opposed corner of the tile. In use, a tile is placed upon the base  20  with one corner located in recess of the land and the clamp jaw body  101  is adjusted to receive the opposed corner of the tile at recess  102 . 
     In order to positively and accurately guide the cutter wheel  52  along its rectilinear path it is necessary for the carriage body  41  to move along rails  30  without any significant lateral displacement. In addition, it is highly desirable for movement of the carriage body  41  along the rails  30  to be as smooth as possible despite dust and particles from the tiles being cut being deposited onto the rails  30 . 
     In order to achieve these capabilities, the carriage body  41  is preferably movably mounted on each rail  30  by a pair of bearing assemblies  150 . Each bearing assembly  150  preferably includes two pairs of opposed bearing rollers  151  which are located on opposite sides of a rail  30 . 
     In an alternative embodiment, each bearing assembly  150  includes lower rollers  151  only, and no upper rollers  151 . 
     Each roller  151  preferably comprises a shaft  153  having a pair of axially spaced bearing wheels  154  mounted thereon so as to be axially fixed relative to the shaft. Each wheel  154  has an inner axial face  170 , a circumferential face  171  and a transitional face or corner portion  155  extending between the inner axial face  170  and circumferential face  171 . 
     The transitional face or corner portion  155  defines a contact face for rolling contact between each wheel  154  and rail  30 . 
     The spacing between each wheel  154  of a pair is such that the corner portion  155  of both wheels  154  only makes contact with the rail  30 . Thus the opposed corner portions  155  of each pair of wheels  154  when seated upon a rail  30  co-operate with one another to prevent lateral displacement of the roller  151  relative to the rail  30 . Preferably the corner portions  155  are chamfered or rounded. 
     Each roller  151  has a shaft extension  156  at each end which is located within a groove  160  formed within the carriage body  41 . In FIGS. 6 and 7 only the lower half of carriage body  41  is illustrated. 
     The grooves  160  accommodating opposite ends of each roller  151  have thrust bearing walls  161  located adjacent thereto against which the outer axial end faces  154   a  of wheels  154  abut. The distance between opposed thrust bearing walls  161   n  is substantially the same or slightly larger than the distance between the outer axial faces  154   a  of the wheels  154 . This ensures that there is no significant axial displacement of the roller  151  relative to the carriage body  41  and hence enables the body  41  to move along rails  30  without any significant lateral displacement relative to the rails  30 . 
     Since the corner portion  155  of each wheel  154  forms the only contact between each roller  151  and rail  30 , there is a minimal amount of surface contact therebetween and so enables the roller  151  to run along a rail  30  in a smooth manner despite the presence of dust or tile particles. 
     In an embodiment of the invention in which the rail  30  is polygonal in section, each roller  151  would comprise a ball-like wheel mounted on a shaft. 
     The carriage body  41  defines internal passageways  180  through which respective rails  30  pass. Accordingly, each rail  30  passes through apertures  40   a,    40   b  located at the front and rear of the carriage body  41 . 
     Preferably annular seals (not shown) are mounted on the carriage body adjacent each aperture  40   a,    40   b  for wiping the rails  30  in order to protect the interior of the carriage body  41  from an excessive ingress of dust or tile particles. This also contributes to the wheels  154  contacting a relatively clean portion of the rails  30  and so contributes to the smooth running of the carriage body  41  along rails  30 . The annular seals may be formed from a suitable elastomeric material and be in the form of a bellows mounted on annular seat  40   c.    
     When the carriage  40  is pulled along the rails  30  by an operative during scoring of a tile, the handle  54  is pulled upwardly in order to apply a downward pressure onto the tile through the cutter wheel  52 . This in turn produces an upward biasing force onto carriage body  41 . Thus the bottom wall  162  of each groove  161  in the lower half of carriage body  41  is urged upwardly into abutment with the shaft extensions  156  of rollers  151  located therein and these in turn are urged upwardly into abutment with the lower side of the rails  30 . Accordingly play between the lower rollers  151 , carriage body  41  and rails  30  is removed during the scoring process and the carriage body  41  is positively guided primarily by the lower bearing roller  151 . In fact, the upper bearing rollers  151  are not necessary during scoring and breaking of a tile, although they do allow smooth return of the bearing assembly to the far end of the rails  30  after scoring. 
     Neither the upper, nor the lower rollers  151  are positively based into contact with the rail. This prevents the rollers  151  from “nipping” the rail, which in turn prevents excessive wear to the bearing. 
     The rollers  151  may be conveniently moulded from a rigid, wear resistant plastics material such as a glass filled Nylon or be made from a suitable metal.