Patent Publication Number: US-6670019-B2

Title: Arrangement for jointing together adjacent pieces of floor covering material

Description:
TECHNICAL FIELD 
     The present invention relates to a jointing of adjacent pieces of floor covering material, edge portions of the pieces facing towards one another in a joint being profiled such that the one piece has a groove-shaped accommodation space in which a corresponding bead-shaped projection on the other piece may be accommodated, and at least one of the pieces displaying a flocking which is provided for joining together adjacent pieces. 
     BACKGROUND ART 
     SE 503 917 C2 discloses a structure of the above-outlined type. In this structure, the one piece of floor covering material has its accommodation space designed as a groove, while the other piece of floor covering material has its projection designed as a tongue. According to this patent specification, at least one of adjacent surfaces on the tongues and grooves of the pieces is provided with flocked surface portions. 
     The structure according to the above-disclosed patent specification provides a very reliable jointing together of adjacent pieces of floor covering material, but also suffers from certain difficulties. 
     Since the described structure realises a considerable resistance against separation of adjacent pieces, assembly and jointing together of these pieces will be correspondingly difficult, since the pieces must be slid in place in a direction which is wholly opposite to the direction of withdrawal. The grip of the flocking is the same in both directions. 
     Further, manufacture of such jointing may offer certain problems in that use is made of electrostatic fields in the application of the flocking. It has proved difficult to realise a more or less uniform and sufficiently powerful electrostatic field at least interiorly in the grooves. 
     PROBLEM STRUCTURE 
     The present invention has for its object to obviate the drawbacks inherent in prior art structures, in particular in the structure as disclosed in the above-considered patent specification. Thus, the present invention has for its object to design the structure intimated by way of introduction such that it obviates the drawbacks inherent in the prior art methods and devices. In particular, the present invention has for its object to design the arrangement mentioned by way of introduction such that jointing together of adjacent pieces of floor covering material is substantially facilitated without the union bond of the pieces in the assembled state being weakened or otherwise jeopardised. Further, the present invention has for its object to design the arrangement such that its manufacture is considerably facilitated. Finally, the present invention generally has for its object to realise an arrangement which is economical and simple in manufacture, convenient in assembly and also displays good mechanical strength in the assembled state. 
     SOLUTION 
     The objects forming the basis of the present invention will be attained if the arrangement intimated by way of introduction is also characterized in that the profiling besides the accommodation space and the projection has mutually facing surfaces on both of the flooring pieces, at least one of these surfaces being flocked. 
     Further advantages will be attained according to the present invention if the arrangement is also given one or more of the characterizing features as set forth in the instant specification. 
     The present invention also relates to a floor covering material which has the same sought-for properties as the above-considered arrangement. 
    
    
     BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS 
     The present invention will now be described in greater detail hereinbelow, with reference to the accompanying Drawings. In the accompanying Drawings: 
     FIG. 1 shows in perspective corner portions of two pieces of floor covering material laid against one another; and 
     FIG. 2 is a view corresponding to that of FIG. 1 of a second embodiment of the present invention. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENT 
     FIG. 1 shows in perspective two pieces  1  and  2  of a floor covering material designed according to the invention. The pieces  1  and  2  are preferably of identical design, for which reason the piece  1  (to the left in the Figure) has a left-hand edge (not shown) which is designed in the same manner as the left-hand edge of the piece  2  shown in the Figure. 
     Conversely, the opposite relationship naturally applies such that the piece  2  has a right-hand edge (not shown) which corresponds to the right-hand edge of the piece  1  according to the Figure. The end surfaces of the pieces  1  and  2  may be cut as shown in the Figure, but may also be profiled in the manner shown on the pieces  1  and  2 . 
     Each piece  1  and  2  has a bearing, panel-shaped portion  3  which may consist of chipboard, MDF plate, coreboard, solid wood, etc. Further, each piece has a wear surface  4  which preferably consists of a high-pressure laminate or the like. On the underside, the pieces have a barrier layer which prevents the pieces from warping in the event of variations in moisture content and temperature. 
     Alternatively, the pieces  1  and  2  may, in their central region counting in the vertical direction, have a core of the same material type as the bearing portion  3 . On the upper side of this core, there is then provided a wear layer of relatively thick wood veneer, while there is disposed on the underside a corresponding barrier layer. 
     Regardless of how the pieces  1  and  2  are composed, they are provided, along their edge portions facing towards one another in a joint, with profiles which, on the one piece, comprise a groove-shaped accommodation space in which a corresponding bead-shaped projection on the other piece may be accommodated. Suitably, the accommodation space and the projection are approximately complementary to one another. 
     The profilings on the two pieces  1  and  2  further include, in addition to the accommodation space  5  and the projection  6  in the jointed state of the pieces, mutually facing and substantially mutually abutting surfaces  7  and  8 , respectively. These mutually facing surfaces  7  and  8  are preferably approximately parallel with the plane of extent of the pieces  1  and  2 , such that the one surface  7  will be turned to face upwards and the other surface  8  will be turned to face downwards. Of the mutually facing surfaces, at least one is provided with a flocking  9  for interconnecting the adjacent surfaces  1  and  2 . 
     If maximum reliability is to be achieved against separation of the pieces  1  and  2  from the jointed state, both of the surfaces  7  and  8  are suitably provided with flocking. 
     In the vertical direction (thickness) of the pieces  1  and  2 , the two mutually facing surfaces  7  and  8  are located approximately in the central region. This affords the advantage that the portions of the profilings which carry the two surfaces  7  and  8  and the flocking or flockings  9  (and thereby are to hold together the pieces) display superior mechanical strength. However, the surfaces  7  and  8  may be located lower, for example down towards a third of the distance from the bottom. 
     On application of the flocking or flockings  9 , the relevant surface  7  or  8  (or both) is provided with a strip-shaped application of an adhesive  10  in which short pieces of fibre are secured. By exposing the fibres to an electrostatic field, these will be charged and repel one another, for which reason they will, before the adhesive has dried or hardened, be aligned in directions which are substantially at right angles in relation to the plane of the surfaces  7  and  8 . Given that the surface portions coated with the flocking  9  are disposed substantially outside these surfaces which define the accommodation space  5  and the projection  6 , no problems arise as regards the electrostatic field. An interior coating in a groove of the type represented by the accommodation space  5  could, on the other hand, present difficulties. 
     The profiling of the two pieces  1  and  2 , which are substantially complementary to one another, further includes upper and lower transverse surfaces  11  and  12 , and  13  and  14 , respectively. Of these surfaces, the upper transverse surfaces  11  and  13  may be considered as complementary to one another, which also applies to the lower surfaces  12  and  14 . Further, the accommodation space  5  and the projection  6  are suitably complementary to one another. 
     The surfaces  11 - 14  are transversely directed in relation to the plane of extent of the two pieces  1  and  2  and are suitably approximately at right angles to these planes. Further, the corner transitions between the two upper transverse surfaces  11  and  13  are sharp, preferably at right angles in relation to the upper defining surfaces of the pieces  1  and  2 . In this context, it is also possible to conceive of causing the two wear surfaces  4  to extend one or possibly a few tenths of a millimeter outside the two upper transverse surfaces  11  and  13 . 
     The pieces  1  and  2  are joined together in the following manner: the left-hand piece  1  in the Figure is considered as lying fixed on a substrate and, therefore, is included in a floor covering. The right-hand piece  2  in the Figure is inclined at an angle of 15-30° in relation to the piece  1 , so that the arched or rounded edge of the projection  6  may readily slide over the flocking  9  in towards the accommodation space  5 . On insertion of the projection  6  into the accommodation space, the right-hand piece  2  is gradually pivoted until it lies in the same plane as the left-hand piece  1 . During this combined moving together and pivoting action, the flockings  9  will come into mesh with one another increasingly as the movement continues. Complete mesh does not occur until when the pieces  1  and  2  approach the entirely jointed position in a common plane. In order to minimise or wholly eliminate the gap between the upper transverse surfaces  11  and  13 , it may possibly be appropriate to subject the right-hand edge of the right-hand piece  2  to careful impact during the final phase of the moving together of the pieces so that complete union of the pieces will thereby be guaranteed and complete mesh between their flockings. 
     DESCRIPTION OF ALTERNATIVE EMBODIMENTS 
     FIG. 2 shows a modified embodiment of the present invention. This embodiment has arisen so as to maximise the union of the pieces  1  and  2  of floor covering material. This maximisation must, however, be bought at the cost of a slightly weaker jointing of the pieces  1  and  2 . 
     The difference vis-à-vis the embodiment according to FIG. 1 is substantially that the joint region between the pieces  1  and  2  has two groove-shaped accommodation spaces  5  and  5 ′ for accommodating corresponding, bead-shaped projections  6  and  6 ′. The profiling of the pieces  1  and  2  according to FIG. 2 has further upper transverse surfaces  11 ,  13 , respectively, which are arranged fully analogous with that disclosed above in connection with FIG.  1 . Correspondingly, the joint region has lower transverse surfaces  12  and  14 , which are also wholly analogous with the lower transverse surfaces carrying the same reference numerals and considered with reference to FIG.  1 . 
     The surfaces on the pieces  1  and  2  which carry or cooperate with the flockings  9  or with the flocking  9 , respectively, are disposed in the vertical direction approximately in the central region of the pieces, and are approximately parallel with the plane of extent of the pieces. The flocked surface or surfaces have been given the same reference numerals,  7  and  8 , as the corresponding surfaces in the above-considered embodiment. 
     The flocked surfaces  7  and  8  may be seen as extensions or continuations of defining surfaces to the two grooves  5  and  5 ′ respectively. 
     The present invention may be modified without departing from the scope of the appended claims.