Abstract:
Attachment devices are described for attaching and locating overlapped anchor sheets while allowing for some relative movement as to expansion and contraction. Generally, the devices are a male/female connection on corresponding sheets and expansion openings or apertures surrounding either the male or female part to provide for areas of flexibility to provide for possible movement of either the male or female part.

Description:
This application claims priority from and is a divisional application of U.S. patent application Ser. No. 10/543,901 filed Mar. 10, 2006 now U.S. Pat. No. 7,980,040 (based on an international filing date Jan. 29 2004), which is a national phase entry of PCT/CA2004/000116 filed Jan. 29, 2004 designating the United States, which claims priority from U.S. Patent Application No. 60/443,563 filed Jan. 30, 2003. All of these applications are incorporated herein by reference in their entireties. International Patent Application No. PCT/CA2004/000116 was published in English under Article 21 of the Patent Cooperation Treaty under WO 2004/066794 on Aug. 12, 2004. 
    
    
     FIELD OF THE INVENTION 
     Structures are disclosed for creating a sub-floor or other horizontal surface of hooks, the surface being formed from adjacent anchor sheets connected by attachment pieces. 
     BACKGROUND OF THE INVENTION 
     Several earlier patents by one of the same inventors disclose an anchor sheet which can be supplied as a small or large module, with or without a pre-attached decorative covering. U.S. Pat. Nos. 6,306,477; 6,298,624 describe anchor sheets. Such anchor sheet is also described in a more detailed way in international patent application number PCT/CA00/00681, that was published under WO 00/74544 on Dec. 14, 2000, and U.S. application Ser. No. 09/008,584 filed Jan. 16, 1998, the specifications of all of which are incorporated by reference. These earlier applications also disclose the anchor sheet as a modular unit, many of which many can form a contiguous mass of anchor sheets to be used as a sub-floor. A decorative covering may be attached to the sub-floor, or the sub-floor may be used as a finished floor when presupplied with a decorative surface. Such a contiguous mass can be formed by attaching the anchor sheets together by some form of overlap or by abutting the anchor sheets to each other and using an overlap of decorative covering or tape. Such mass can be free floating or attached to the floor. 
     SUMMARY OF THE INVENTION 
     The current invention relates to improved anchor sheets and attachment pieces which when abutted or overlapped can form a generally-flat planar sub-floor or other surface for detachable attachment of overlying decorative pieces, preferably with a hook and loop system. The attachment pieces (also called attachment devices or corner pieces, because they frequently fit into the corner of another sheet), are really generally smaller anchor sheets provided with one-half of a male or female connection, the other half of the male or female connection being placed upon the “main” anchor sheet. It should be appreciated, however, that the size of the anchor sheet and anchor or attachments pieces is somewhat arbitrary. It is possible to have quite small anchor sheets and very large attachment pieces so that, in effect, there is no distinction between the “attachment pieces” and the anchor sheets. Effectively there are two sets of sheets which are overlapped to form a planar surface. In practice, one of the sheets will have a countersunk area of a thickness matching the thickness of at least a portion of the other sheet, so that when overlapped, a planer, substantially flat surface will be presented. Also, generally in practice, one of the sheets will be of a size to substantially cover the floor, with the other sheet being substantially smaller (generally called the “attachment piece”), for fitting into the countersunk area of the anchor sheet. Both the anchor sheets and the attachment pieces themselves are preferably made of polypropylene, or some other plastic. Such plastic may expand and contract according to temperature and humidity. The anchor sheets (and attachment pieces), are preferably designed to have hooks on their upper surface, which receive a covering of decorative pieces, which have loops complimentary to the hooks. If the decorative pieces are, for example, carpet pieces, then it is also advantageous to additionally allow for expansion and contraction of the carpet pieces, by allowing for relative movement of the anchor sheets. However, the anchor sheets themselves also can expand and contract according to temperature and humidity, and therefore, it is advantageous to allow for some expansion and contraction in any event. 
     It is also advantageous to have the sheets connected together in a positive way, but so as to prevent anchor pieces and anchor sheets from rising up or riding up in relation to each other, which could create anon-planar surface. Thus, it is helpful for the attachment to have a positive connection in a direction at right angles to the plane of the surface, for example a floor, while allowing for some relative movement in a direction along or with the plane of the floor. It is also advantageous if a connection can provide for positive registration, so that the sheets are oriented and spaced in relation to each other by the attachment piece. 
     Thus, in one aspect of the invention, there is provided a structure for attachment between attachment pieces and anchor sheets, which allows for relative movement between the attachment piece and each anchor sheet, and therefore relative movement between anchor sheets forming a planar surface. This structure can also create a suitable space in between anchor sheets during installation, by setting a connection point between the anchor sheets and the attachment pieces. In another aspect of the invention, one of either the anchor sheet or attachment piece has a male connection and the other a female connection. One of the sheets has a countersunk area containing the one-half of a male and female connection, and the other sheet or attachment piece has the other half of the male-female connection. In addition, either the female element is provided with means for motion of the aperture into an expansion space, or the male element is provided with means so that it can move into an expansion space in a direction along the plane of the floor. 
     Thus, in one aspect, the invention comprises a male and female connection for overlapped sheets, comprising the following: (i) a first anchor sheet having a substantially horizontal surface, and having a portion countersunk from the horizontal surface at, at least, one edge; and (ii) a central aperture within the countersunk portion; and (iii) a second anchor sheet having at least an overlap portion of a thickness to fit into the countersunk portion of the first anchor sheet, to present a substantially planar surface, the second sheet having a male member having a shaft sized to fit into the aperture on the first sheet member, and having a second portion larger than the aperture at the end of the shaft to create a cam surface means to prevent removal of the male member from the aperture, in which at least one of the male or female members have expansion openings or areas of flexibility in the first or second sheets surrounding either the male member or female aperture, to provide for movement of either the male or female part, in a path between the expansion areas. 
     In a second aspect, the invention comprises a first sheet member to connect to an overlapped second sheet member to form a substantially horizontal surface, comprising the following: (i) the first sheet member having a first surface and a countersunk surface below the level of the first surface; (ii) the first sheet member having in the countersunk portion a first aperture; (iii) the sheet, provided on two opposite sides of the first aperture with expansion openings proximate to the first aperture, so as to create areas in the sheet of increased flexibility, from either side of the first aperture and a path substantially in the line drawn between the middle of the second and third apertures. 
     In another aspect, the invention comprises a male sheet member to connect to an overlapped female sheet member to form a substantially horizontal surface, comprising: (i) a sheet member of a thickness substantially the same as the depth of a countersunk portion on a corresponding female sheet member and having a first upper surface; (ii) a snap-fit means comprising at least two flexible prongs projecting from the opposite bottom surface, and having a normal memory position, of a size slightly larger than the size of an aperture of a corresponding female sheet member, each prong having a cam surface projecting radially outwardly. 
     In an additional aspect of the invention, the invention comprises: (i) a first sheet member having a first surface and a countersunk surface below the level of the first surface, the first sheet having, in the countersunk portion, a first aperture of a diameter x, and a channel of a smaller diameter, and a second sheet member with at least an overlapping portion of a thickness matching the thickness of the countersink of the first sheet member and, having a male member with a stem and a head. The head fits into the aperture of the first sheet member in a first location and the stem has a thickness corresponding to the channel of the first sheet member, so that the second sheet member can be inserted into the first sheet member through the aperture and the shaft moved into the channel to prevent upward motion of the head and of the first sheet member in relation to the second sheet member, and in which the male sheet member contains areas of expansion and flexibility on opposite sides of the male member, so as to provide for flexible movement of the male sheet member in relation to the second sheet along a path drawn between the areas of flexibility surrounding the male member. The areas of expansion may be apertures surrounding the male or female members. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a portion of an anchor sheet showing a countersink. 
         FIG. 2  shows four anchor sheets overlapped on a floor. 
         FIG. 3  shows an anchor sheet and attachment device. 
         FIG. 4  is a perspective view of an attachment piece from below. 
         FIG. 5  is a perspective view of an anchor sheet to receive the attachment piece of  FIG. 4 . 
         FIG. 6  is a plan view of an attachment piece and surrounding anchor sheets with complementary first and second halves of a flexible detachable attachment. 
         FIG. 7  is an alternative embodiment for a first and second anchor sheet showing a male member with areas of flexibility. 
         FIG. 8  is a detail of the male member of  FIG. 7 . 
         FIG. 9  is a detail of the male and female member of  FIG. 7  united on a sheet, in plan view from above. 
     
    
    
     DETAILED DESCRIPTION 
     Preferably in the preferred embodiment, as shown in  FIG. 1 , an anchor sheet  1  has a polyethylene layer  9 , in which there is a countersunk area  7  at (in this case), a corner. The sheet is made of polyethylene and is substantially covered with hooks  4  that are injection molded into the sheet. Details of this are described in the corresponding applications entitled “System and Methods of Manufacturing Hook Plates” and “Improved Anchor Sheet” by some of the same inventors filed concurrently herewith, and in earlier cases described earlier in this application, all of which are incorporated herein by reference. The anchor sheet typically has a resilient layer  5 , but this is not necessary for the operation of this invention. Contained within the countersunk area, in at least one embodiment, is an aperture  15  and surrounding expansion areas  16  and  17 , which will be described more fully in detail later. 
     Shown in  FIG. 2 , is a series of anchor sheets, which in this embodiment have an overlapping area  23  and  25 , but such overlapping area is also not necessary for this invention. In  FIG. 2 , the countersunk area for the attachment device is shown at  21 . 
       FIG. 3 , shows an anchor sheet also having a countersunk area  7 , an aperture  15  and expansion areas in the sheet  16  and  17 . These are areas of reduced strength, so as to allow for movement of the rim  14  around the aperture  15  into the expansion areas as will be described later.  FIG. 3  also shows, an attachment device  31 , which typically will contain a male protrusion  33 , projecting onto its under-surface, and which will conform to and fit into aperture  15 , as also will be described in further detail later. 
       FIG. 4 , shows in more detail, a male prong  33  as seen from below attachment device  31 . Registration members  35  are also placed underneath attachment piece  31 . Male prong  33  is a flexible protrusion, which has a normal memory position as shown in  FIG. 4 , which is slightly larger than aperture  39 . It has a cam surface  37 , which contains an edge slightly larger than the corresponding aperture  39  contained in the sheet  1 . Shown in  FIG. 5 , is sheet  1  having aperture  39 . There is also a corresponding indentation  41 , which matches with the registration member  35  to help centre the snap-fit connection. In practice, male prongs  33  have sufficient flexibility that they can move slightly into aperture  39 , but are normally in a position whereby cam surface  37  fits onto the edge  43  of aperture  39  to prevent disengagement of the attachment device  31  from the anchor sheet  1 . As will be explained later, there are apertures or expansion openings  45  through the polyethylene sheet  1 , and surrounding the aperture  39  on opposite sides, so as to create effectively a structure whereby the aperture  39  is surrounded by a thin surrounding layer of plastic  47  as a rim on two sides of the aperture, thus to allow the aperture to move in a path between the two expansion openings  45 . The movement of the aperture allows for some movement of the whole connection between the attachment device  31  and anchor sheet  1  as will be described later. Some movement is also available because of movement of the prongs  33 . By appropriate placement of the aperture  39  and prongs  33  in of the overlap area of an attachment piece  31  and the overlap of an anchor sheet  1 , an appropriate space can be created between the attachment piece and the anchor sheet. During atmospheric expansion and contraction, the flexibility of prong  33  and the flexibility of rim  47  and  48  around surrounding opening  39 , allow rim  47  and  48  to move into the expansion openings  45  as necessary to accommodate expansion and contraction. 
     The prong  33  and rim  47  and  48  may be made from the same material as the anchor sheet or the attachment piece, as long as the material is sufficiently flexible. It is preferred that the material be polypropylene or polyethylene. For example, polypropylene such as that sold as STAMYLAN™ P112MN40 with an ISO of 1873 indication of PP-H,MA-M400 is acceptable. This material has a melt-flow index of 50 (T-230 degrees C., F=2.16 kg) a tensile modulus of 1900 MPa, proportional strength of 35 MPa, ultimate strain of greater than 50%, a density of 910 kg/m 2 , and a melting point of approximately 160 degrees Celsius. The attachment device  31  may include two registering pins  35  and two corresponding indentations  41  for receiving pins  35 . Pins  35  and indentations  41  co-operate to align the attachment piece  31  with the anchor sheet  1 . This arrangement can encourage atmospheric expansion and contraction to occur, in a direction along a line  572  or  574  that passes approximately through the middle of expansion openings, as shown in  FIG. 6 . In  FIG. 6 , attachment piece  430  has male members  432 ,  434 ,  436 , and  438  on the bottom surface of its upper-disk, with corresponding registering pins  440 ,  442 ,  444 , and  446 . These fit into corresponding openings  448 ,  450 ,  452 , and  454  and corresponding pin receptacles  456 ,  458 ,  460  and  462 . After the prongs and registering pins are inserted into the corresponding round opening and pin receptacles, atmospheric expansion and contraction will be encouraged to take place generally through the centres of the horseshoe openings  464 ,  466 ,  468  and  470 , along lines  574  and  572 . It is not necessary to restrict the expansion and contraction to these lines, but it is thought in practice that this is the natural way that the sheets will expand and contract. 
     Referring to  FIG. 3 , while in the above description, the first half of the attachment device has been described as being ad attachment piece  31 , and the second half has been described as being on an anchor sheet  1 , there could be a reversal of the male and female members, however because the male member projects down into the resilient layer  5 , it is preferable to have the male member on the attachment piece which is projecting into the resilient layer. 
     As shown in  FIG. 7 , male member  61  can also be provided with expansion openings  63  and  65 , which will allow for the male member to move on the attachment device  31 . In this embodiment, male member  61  is inserted into keyhole  67 , and then twisted to move into channel  69 . The flange or cam surface  71  on male member  61 , prevents the upward Movement of attachment piece  31  once it has been moved into channel  69 . In addition, there are also registration pins  73  on the underside of head  61 , which can register with small indentations  75  to locate the attachment device  33  in relation to the anchor sheet  1 . As shown in  FIG. 8 , registration pins can also be registration receptacles  77 , so co-operate with pins at locations  75  on anchor sheet  1 .  FIG. 8  also shows the expansion opening  63  in greater detail.  FIG. 9  shows the attachment device  31  and the anchor sheet  1  shown in plan view from above. Because of the countersink, attachment device  31  and anchor sheet  1  are on the same plane, presenting a flat surface. Not completely shown; but to be understood, is that typically the anchor sheet will be covered in hooks (not shown), as will the attachment device  31 . 
     It is noted that those skilled in the art will appreciate the modifications of detail may be made from the embodiments described herein which would come within the spirit and the scope of the invention as described in the following claims.