Patent Abstract:
A floor tile expansion joint accommodates differential thermal expansion or contraction of modular floor tiles used in flooring applications. One or more rows of floor tile expansion joints may be connected to modular floor tiles for various floor tile applications.

Full Description:
BACKGROUND OF THE INVENTION 
     Modular floor tiles may be laid across the surfaces of garage floors, sports surfaces, outdoor surfaces and other substrates. Occasionally the floor tiles are installed in areas in which they are exposed to variations in temperature such as direct sunlight or heating and air-conditioning ducts. These temperature variations may cause the floor tiles to expand or contract. Some of the tiles may be exposed to these heating or cooling effects while others may not, leading to differential thermal expansion or contraction. In instances where the floor is installed in such a manner that it is not allowed to float or if heavy objects are placed on the floor which consequently inhibit float, the temperature variations may cause buckling or separation between the tiles. 
     Thus a need exists for an expansion joint that attaches to the tiles and integrates with the flooring application and accommodates floor tile expansion and contraction due to temperature fluctuations. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the invention, an expansion joint is molded from thermoplastic material. The expansion joint is separable into a first and second expansion body. The first expansion body has a web with a general upper surface and a general lower surface. A plurality of edge surfaces extend from the general upper surface to the general lower surface. An outer edge surface with at least one connector is disposed on the first expansion body. 
     The second expansion body also has a web with a general upper and lower surface. An outer edge surface is one of the plurality of edge surfaces which extend from the general upper surface to the general lower surface. A connector is formed on the outer edge surface of the second expansion body. The connectors on the first and second expansion bodies allow the expansion joint to be connected to modular floor tiles or other expansion joints. 
     At least two spaced apart fingers project from the general lower surface of the first web in alignment with a direction of expansion and contraction and at least one spaced apart finger projects from the general lower surface of the second web, also in alignment with a direction of expansion and contraction. The fingers are positioned such that the second finger is slidably received into the channel defined by the first fingers. 
     According to another aspect of the invention, a system includes modular floor tiles and expansion joints for creating a flooring surface. The plurality of modular tiles each have connectors which connect to the either first or the second expansion joint body. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       Further aspects of the invention and their advantages can be discerned in the following detailed description, in which like characters denote like parts and in which: 
         FIG. 1  is an isometric view of one embodiment of an expansion joint according to the invention, fitted between neighboring modular floor tiles; 
         FIG. 2A  is an exploded detail top view of the expansion joint shown in  FIG. 1 ; 
         FIG. 2B  is an exploded detail bottom view of the expansion joint shown in  FIG. 1 ; 
         FIG. 3A  is an isometric detailed view of the expansion joint shown in  FIG. 1 , showing two expansion joint bodies in a contracted position; 
         FIG. 3B  is an isometric detailed view of the expansion joint shown in  FIG. 3A , but in a neutral position; 
         FIG. 3C  is an isometric detailed view of the expansion joint shown in  FIGS. 3A and 3B , but in a fully expanded position; 
         FIG. 4A  is an isometric bottom view of the bottom of the expansion joint shown in  FIG. 1 , in a fully contracted position; 
         FIG. 4B  is an isometric bottom view of the expansion joint shown in  FIG. 4A , in a neutral position; 
         FIG. 4C  is an isometric bottom view of the expansion joint shown in  FIGS. 4A and 4B , in a fully expanded position; 
         FIG. 5A  is cross-sectional view taken substantially along the line  5 A- 5 A of  FIG. 3A ; 
         FIG. 5B  is cross-sectional view taken substantially along the line  5 B- 5 B of  FIG. 3B ; 
         FIG. 5C  is cross-sectional view taken substantially along the line  5 C- 5 C of  FIG. 3C ; 
         FIG. 6  is a detailed exploded top view of a portion of an expansion joint shown in  FIG. 2A ; 
         FIG. 7  is a detailed exploded bottom view of a portion of an expansion joint channel shown in  FIG. 2B ; 
         FIG. 8  is an isometric view of a floor tile system, showing differential thermal expansion of the floor tiles and the effects thereof on two expansion joints; 
         FIG. 9  is an isometric view of a filler piece according to the invention, fitted to modular floor tiles and expansion joints; 
         FIG. 10  is a detail view of the filler piece shown in  FIG. 9 ; 
         FIG. 11A  is a detailed exploded bottom view of a border piece shown in  FIG. 8 ; 
         FIG. 11B  is a detailed exploded top view of a border piece shown in  FIG. 8 ; and, 
         FIG. 11C  is a detailed view of a border piece in an assembled, expanded position. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention provides an expansion joint for use in creating a floor surface of modular floor tiles where the floor surface expands and contracts, if necessary, in response to thermal variations between the tiles. The expansion and contraction of the expansion joint allows the floor surface to accommodate uneven temperature shifts across the floor thereby preventing buckling or separation. In the illustrated embodiment shown in  FIG. 1 , two expansion joints indicated generally at  100  are shown. The expansion joints  100  are positioned in between modular floor tiles  102 . Expansion joints may be placed approximately five feet apart from each other in a modular floor tile application or system, but specific spacing will be application specific. Considerations to be taken into account when determining the placement of expansion joints include the span of the application, exposure to sunlight and heating and cooling ducts, and the placement of heavy objects such as vehicles, cabinetry and machinery. In addition, in the illustrated embodiment of  FIG. 1 , the expansion joints  100  are shown going in only one direction. However, expansion joints may be placed along both directions (along the x and y axis) depending on the specific application. Each expansion joint is preferably formed from a polymeric material but may also be formed from a ceramic or cellulosic material. The present invention has application to any modular floor tile system in which the modular tiles have a non-negligible coefficient of linear thermal expansion. 
     As shown in  FIGS. 2A-2B , the expansion joint  100  consists of two expansion bodies,  202   a  and  202   b . The first expansion body,  202   a , has a web  204   a , and at least two fingers  206 ; the illustrated embodiment shows eight fingers  206 . The web  204   a  has a general upper surface  208   a , a general lower surface  210   a  and an inner margin  216   a . As better seen in  FIGS. 5A-C , in this embodiment the inner margin  216   a  is curved in a vertical direction. In further embodiments the curvature may be different than the curvature shown in  FIGS. 2A-2B . An outer edge surface  222  extends from the general upper surface  208   a  to the general lower surface  210   a  of the first expansion body  202   a.    
     The second expansion body  202   b  also has a web  204   b , and at least one finger  206 ; the illustrated embodiment shows eight such fingers  206 . The web  204   b  has a general upper surface  208   b  and a general lower surface  210   b  and an inner margin  216   b . The inner margin  216   b  of the second expansion body is preferably also curved in a vertical direction. In further embodiments the curvature may be different than the curvature shown in  FIGS. 2A-2B . As shown in the illustrated embodiment an outer edge surface  220  on the second expansion body  202   b  extends from the general upper surface  208   b  to the general lower surface  210   b  and is opposed to the outer edge surface  222  when the expansion joint bodies  202   a ,  202   b  are connected. 
     Also shown in  FIGS. 2A and 2B , a first connector  214  is disposed on edge surface  222  and a second connector  212  is disposed on edge surface  220 . In this embodiment the first connector  214  is a latch and the second connector  212  is a loop. The loop connector  212  is designed to receive the latch connector  214 , hence the expansion joint will mate with floor tiles  102  on which mating latch and loop connectors are disposed. Alternative embodiments may include a variety of connectors such that the connectors disposed on the expansion joint  100  mate with the connectors on the floor tiles  102  of the desired application. 
     As shown on  FIG. 2B , at least two ribs  230  downwardly depend from the general lower surface  210   a  or  210   b  of the web  204   a  or  204   b . Each rib  230  is disposed on either side of a channel  228 . Each rib  230  is aligned with either a first or second side of a respective finger  206  and extends outwardly, and, in the illustrated embodiment each rib is an extension of a side surface  244 ,  246  of a respective finger  206 . The general lower surface of each of the ribs  230  is generally co-planar with the general lower surface of the fingers  206 . The ribs provide additional support and stability to the expansion joint when fully expanded. The ribs  230  also aid in guiding the mating fingers  206  into position. In alternative embodiments, the ribs may be selected to be different lengths than the length illustrated or have varied lengths among the ribs themselves. 
     Each channel  228  is sized to receive a finger  206  from the opposing expansion body  202   a  or  202   b . The width of each channel  228  may be slightly greater than the width of each finger  206 . Support members  240  and  242  downwardly depend from the general lower surface  210   a  or  210   b  of the web  204   a  or  204   b  and terminate on a bottom plane which is in general alignment with a bottom surface  234  of the fingers  206 . The support members  240 ,  242  are proximate to edges  220  and  222 . In the illustrated embodiment, the support members  240  and  242  downwardly depend from the lower surface of the web  210   b  to a height that is approximately equivalent to the height of the ribs  230 . The placement of the support members  240 ,  242  may be partially determined by the placement of the connectors  212 ,  214 . The support members  240  and  242  provide additional support, strength and stability to the expansion joint  100 . 
     As seen in the illustrated embodiment in  FIGS. 2A and 2B , the fingers  206  project from the general lower surface  210   a ,  210   b  of the web  208   a ,  208   b  and extend from the inner margins  216   a ,  216   b  in alignment with a direction of expansion and contraction (side to side in these FIGURES). Each finger has a general upper surface  236 , a general lower surface  234  opposed to the general upper surface  236 , a leading edge  232  joining the general upper surface  236  and general lower surface  234  and opposed to the inner margin  216   a ,  216   b , a first side  244  joining the general upper surface  236  and general lower surface  234 , and a second side  246  joining the general upper surface  236  and general lower surface  234  and opposed to the first side  244 . An upstanding post  226  is disposed in close proximity to the leading edge  232  of each finger  206 . The upstanding post  226 , in cooperation with a groove  224  disposed in the other body in the channel  228  on the general lower surface  210   a ,  210   b , determines the range of movement for the expansion joint  100 . The groove  224  is disposed in the channel  228  in alignment with the direction of expansion and contraction. The post  226  is sized to fit into the groove  224  and the length of the groove  224  is selected such that the desired fully compressed and expanded states of the expansion joint can be achieved. In the illustrated embodiment the length of the grooves  224  is smaller than the width of the expansion bodies  202   a ,  202   b . In alternative embodiments the placement of the upstanding post  226  may be one of several positions along the general upper surface  236  to achieve the desired range of motion and the groove  224  may be of varying lengths. 
     In the illustrated embodiment each finger  206  is identical in shape and size. In addition, in this embodiment, adjacent fingers  206  on each respective expansion body  202   a ,  202   b  are equidistant from each other. The width of each channel  228  is generally equivalent (or slightly greater than) to the width of an individual finger  206 . In further embodiments the fingers  206  on the first expansion body  202   a  may be of varying widths and/or spacing as compared to the fingers of the second expansion body  202   b . The sizing and spacing of the fingers  206  may vary provided the fingers  206  of the first expansion body  202   a  are accepted into the channels of the second expansion body  202   b.    
       FIGS. 3A ,  3 B and  3 C illustrate the expansion joint  100  in three different configurations.  FIG. 3B  illustrates the expansion joint  100  in a neutral position with the two expansion bodies  202   a ,  202   b  joined by interlocking the fingers  206 . In this illustrated embodiment the expansion joint  100  has a width of approximately 3 inches. When the expansion bodies  202   a ,  202   b , are joined, the fingers  206  from the first expansion body  202   a  interlock with the fingers of the second expansion body  202   b . The interlocking fingers  206  allow sliding across the width of the expansion joint yet constrain movement lengthwise and upwardly and downwardly. The interlocking fingers give the appearance of a solid tile, however, while the general height of the expansion joint web  204   a ,  204   b  is approximately equivalent to the general height of the floor tiles  102  to which the expansion joint  100  is connected, the height of the interlocking fingers  206  is lower than the general height of the expansion joint  100 ; the height of the fingers  206  is approximately half of the height of the modular floor tiles  102  as measured from the general upper surface  208   a,b  to the bottom plane. 
       FIG. 3A  illustrates the expansion joint in its fully contracted position. In this configuration, the inner margin  216   a  of the first expansion body  202   a  abuts the inner margin  216   b  of the second expansion body  202   b . In the illustrated embodiment shown in  FIG. 3A  the expansion joint has a width of approximately 2⅝ inches. The inner margins  216   a ,  216   b  are linear in the illustrated embodiment. Further embodiments may have inner margins  216   a ,  216   b  with curved, chamfered or other complimentary shapes. The expansion joint  100  will look like this when the adjacent tiles are relatively warm. 
       FIG. 3C  illustrates the expansion joint  100  in a fully expanded position where it has a width of approximately 3⅜ inches. In the fully expanded position, the alternating fingers  206  completely cover the underlying floor surface. The expansion joint will look like this when the adjacent tiles are relatively cool. Alternative embodiments may include expansion joints of different widths, including variations in width of the web  204   a ,  204   b  and length of the fingers  206 . Consequently, alternative embodiments may have different expansion and contraction ranges. 
       FIGS. 4A ,  4 B, and  4 C illustrate one embodiment of the bottom of the expansion joint  100 .  FIG. 4A  illustrates the expansion joint in a fully contracted position. This view corresponds to  FIG. 3A . In the embodiment shown in  FIG. 4A , the fingers  206  of the first expansion body  202   a  interlock with the fingers  206  of the second expansion body  202   b . In this fully contracted position the finger  206  extends slightly past the rib  230 , however in other embodiments the length of the finger  206  and ribs  230  may vary. In addition, in the fully contracted position, each post  226  on a finger  206  is disposed at the end of a respective groove  224  farthest from the inner margin  216   a ,  216   b ; consequently the grooves  224  are not visible. 
       FIG. 4B  illustrates the expansion joint  100  at a neutral position. This view corresponds to  FIG. 3B . In this position, part of the groove  224  is visible adjacent the finger  206 .  FIG. 4C  illustrates the expansion joint at a fully expanded position which corresponds to  FIG. 3C . Here, the majority of the groove  224  is visible adjacent the finger. The ribs  230  and interlocking fingers  206  overlap minimally, if at all, in this position. 
       FIG. 5C  illustrates a cross section of the expansion joint  100  in the position of greatest expansion; this drawing corresponds to the configuration illustrated in  FIGS. 3C and 4C . In this configuration, the post  226  is positioned in the groove  224  at the point closest to the inboard margin  216   b . In other configurations the position of the post  226  and the positional relationship between the post  226  and the groove  224  may be different. 
     Both inner margins  216   a  and  216   b  curve downwardly toward the respective fingers  206  to help prevent cracking, sheer stresses and to promote ease of wheels or rollers rolling across the upper surface. In addition, the curved margins  216   a  and  216   b  help prevent debris buildup in the gap between the two expansion bodies  202   a ,  202   b . The shallow faces on the inner margins  216   a ,  216   b  are easier to clean ensuring contraction will not be inhibited. The inner margin  216   b  partially overlaps the general top surface  236  of the finger  206 . As illustrated in  FIG. 5A  the finger  206  and the ribs  230  have generally equivalent heights, maintaining the expansion bodies  202   a ,  202   b  at a generally constant height. The finger  206  extends across the entire distance between the inner margins  216   a  and  216   b  which provides full coverage of the floor surface below the expansion joint. 
     The illustrated embodiment of  FIG. 5B  is a cross section of the expansion joint in a neutral position, neither expanded or contracted; this drawing corresponds to  FIGS. 3B and 4B . In this embodiment the post  226  is disposed in approximately the midpoint of groove  224 , hence the expansion body  202   b  partially overlaps the finger  206 . 
     The illustrated embodiment of  FIG. 5A  is a cross section of the expansion joint in an contracted position; this drawing corresponds to  FIGS. 3A and 4A . In this embodiment, the post  226  is positioned in the groove  224  at the position furthest from the inboard margin  216   b . Further, in this embodiment, the inner margin  216   a  abuts the inner margin  216   b.    
     The post  226  is shown in greater detail in  FIG. 6 . In this embodiment the post  226  is disposed on the top surface  236  of the finger  206 , near the leading edge  232  of the finger  206 . The post  226  is sized to be accepted into the groove  224  which is shown in a detail view in  FIG. 7 . In this embodiment the groove  224  is disposed on the general lower surface  210   a ,  210   b  of the expansion body  202   a ,  202   b . The position of the post  226  and the position and length of the groove  224  determine the amount of expansion and contraction the expansion joint will be able to accomplish. In further embodiments, the post  226  may be placed on the general lower surface of the expansion body  202   a ,  202   b  with the groove  224  on the general upper surface of the finger  206 . In addition, the post  226  may be located on different areas of the finger  206  providing that the groove  224  is properly placed to ensure the desired expansion and contraction. The fit of the post  226  in the groove  224  is such that the separation of the joint is prevented. 
     In the embodiment shown in  FIG. 7 , the groove is centered in the channel  228  that is situated between adjacent fingers  206 . The length of the channel, in relation to the position of the post  226  on the finger  206 , determines the maximum displacement of the expansion bodies  202   a ,  202   b , during expansion and contraction. 
     When multiple expansion joints  100  are used across a large floor area, the individual expansion joints  100  may expand or contract by different amounts. For example, if part of a floor tile application is in the sun while the opposed portion is under a cold air vent, the expansion joints in the sun may experience contraction as the tiles around them expand, while the expansion joints in the cold air may experience expansion as the tiles around them shrink. Thus, the floor of tiles may experience an expansion as shown in  FIG. 8 . This “V” expansion is accommodated by the design of the fingers  206 . The width of the fingers  206  is slightly smaller than the width of the channels  228 , permitting a slight difference in the displacement vector from the direction of expansion and contraction. 
     The expansion joints  100  are positioned in between modular floor tiles  102  which are molded of at least a first polymer; in further embodiments floor tiles may be molded of a first and second polymer. The floor tiles have bodies with horizontal, substantially planar webs with upper and lower surfaces. The floor tiles each have a first and second edge surface and connectors disposed on the edge surfaces of the tiles. The floor tile connectors mate with the connectors on the expansion joint; in some embodiments the connectors may be mating latch and loop connectors. 
     As discussed above, certain installations may have expansion joints installed at an angle to one another, preferably a right angle. In these cases a filler piece  902  is used at the intersection of the bidirectional expansion joints as illustrated in  FIG. 9 . In the embodiment shown in  FIG. 10 , the filler piece  902  has a raised approximately square puck or platform  1002  with a surrounding flange or platform  1004 . The length and width of the raised puck  1002  is sized to fit in the intersection of the expansion joints  100  when both directions of expansion joints  100  are at the contracted configuration (see  FIG. 3A ). The height of the raised puck  1002  corresponds to the approximate height of general upper surface  208   a ,  208   b  of the expansion joint bodies  202   a ,  202   b . When both expansion joints  100  adjacent to the filler piece  902  expand, the flange  1004  of the filler piece  902  will be exposed. In the illustrated embodiment shown in  FIG. 9 , the underlying floor will not be visible, even when the adjacent expansion joints  100  are fully expanded. 
     In addition, in some applications, the modular floor tiles are connected to “border” pieces  106  that are placed around the outer-most tiles of the application. In these instances, an expansion joint border piece  104  may be used to join the tile borders  106  and provide a continuous outer edge. As shown in  FIGS. 11A-C  the expansion joint border piece  104  is similar to the regular expansion joint. The primary difference is that the expansion bodies  1102   a ,  1102   b  have an angled end that matches the angle on the other border pieces. 
     In summary, an expansion joint has been shown and described which connects to modular floor tiles and allows for expansion and contraction. While illustrated embodiments of the present invention have been described and illustrated in the appended drawings, the present invention is not limited thereto but only by the scope and spirit of the appended claims.

Technology Classification (CPC): 4