Abstract:
The present invention discloses a precast curb and a joint used to constrain the lateral and vertical movement of the precast curb and to align adjacent precast curbs. The precast curb installed with the presented method can be removed after its installation without sustaining any damage and reused later. The method presented hereinafter allows the installation of the curb in almost any weather conditions.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    There is no cross-reference to related applications 
       FIELD OF THE INVENTION 
       [0002]    The present invention generally relates to curbs, especially to precast curbs and their installation. 
       BACKGROUND OF THE INVENTION 
       [0003]    Curbs are border members having a vertical component used to separate a paved section such as a parking or a road from another section which may be, for example, a turf strip, a different area or a road. Usually, these curbs are cast in situ and the major part of the curb is under the ground to provide a high stability and resistance to collision. It also helps also to keep the curd in place notwithstanding the pressure applied by the pavement on one side and by the ground on the other side. A main disadvantage of the usual construction method is that curbs have to be cast in particular weather conditions because of the need for proper curing of the concrete. Furthermore, many highly paid specialised workers are needed for the different steps involved in the construction of an in situ concrete curb and there is nowadays a lack of such specialized workers. 
       OBJECTS OF THE INVENTION 
       [0004]    A first object of the present invention is to provide a curb which is precast. 
         [0005]    Another object of the present invention is to provide a precast curb system and method of installation that allows the curb to be removed after its installation without sustaining any damage and reused thereafter. 
         [0006]    A further object of the present invention is to provide a method of installation of a precast curb having at least the same resistance than cast in situ curbs. 
         [0007]    Other and further objects and advantages of the present invention will be obvious upon an understanding of the illustrative embodiments about to be described or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice. 
       SUMMARY OF THE INVENTION 
       [0008]    The aforesaid and other objectives of the present invention are realized by generally providing a precast curb system, comprising a precast curb having a top, a bottom, a pair of lateral sides and two ends and a joint adapted to be placed between two adjacent precast curbs, the joint having means to constrain relative lateral and vertical movement between adjacent precast curbs. 
         [0009]    The curbs of the present invention are molded prior to their installation in a controlled environment. The curbs are made of concrete and, in a preferred embodiment, are steel reinforced with at least one steel rod. The curbs may be tapered to facilitate their removal from the mold or for aesthetic reasons. 
         [0010]    A first advantage of the present invention is that the precast curbs may be installed in almost any weather conditions. The curing of concrete needs particular environmental conditions and it is most difficult to have these conditions in certain regions, especially in winter and rainy conditions. Also, the method disclosed in the present document requires fewer steps than the usual method for constructing curbs cast in situ. Indeed, in the latter, the formwork has to be made first, reinforcing bars are installed, expansion joints are installed, the concrete is cast into the formworks, workers prepare the concrete (raping and vibrating) and finally the concrete is allowed to cure. Time is critical because the concrete has to be cast quickly otherwise it has to be discarded. Furthermore, the curing period lasts a number of days before the formwork is removed and the earthwork may be completed. The precast curbs of the present invention are manufactured in a controlled environment away from their installation site and are installed directly on the construction site. 
         [0011]    The present invention provides a method of installation of a plurality of precast curbs having a bottom and two ends comprising the following steps; placing a pair of joint, each joint having means to constrain relative lateral and vertical movement between adjacent precast curbs, each joint being placed on the ground at a predetermined distance from each other corresponding to the length of the curb to be installed, and placing each end of a precast curb on one of the joints. 
         [0012]    The joint is used to align adjacent precast curbs and to maintain their relative position. In a first embodiment, the joint is H-shaped; a first and a second vertical plates extend vertically from a horizontal plate. A third vertical plate extends between the lateral plates at the middle of the first and the second vertical plates and two spaces are created to receive an extremity of two adjacent precast curbs. The bottom of the precast curb rest on the horizontal plate. 
         [0013]    In another embodiment, the joint is also H-shaped and adapted to follow the shape of a precast curb which has a frustum section. The joint comprise a first plate and a second plate, their top extremities leaning toward each other and a third plate or other attachment means extending between the first and the second plate. The angle between the first plate and the second are at the same angle than the angle between the lateral sides of the precast curb. This joint provides a high stability between adjacent precast curbs. 
         [0014]    In still another embodiment, the precast curb has a groove along the longitudinal axis on the bottom, adapted to receive a joint. The corresponding joint is a horizontal plate from which a plate extends vertically, on the middle line of the horizontal plate. Two adjacent precast curbs are disposed on the joint, the third plate being received by the grooves of two adjacent precast curbs interconnected with the groove. It is to be noted that even if a precast curb is cut, the joints can still be used. 
         [0015]    The precast curb may also be made in various forms such as corners and T-shaped forms, for example. For driveways, the precast curb may have a lower part to be at the ground level on the road side to allow the passage of cars. 
         [0016]    To displace a precast curb, slots may be molded on the bottom of the precast curb allowing a lift truck or other similar equipment to lift the precast curb. It is also possible to mold two longitudinal recesses along the precast curb, allowing a grip to lift and displace the precast curb. 
         [0017]    The joint may be made from a variety of materials, as long as it can resist the local weather and the forces exerted by adjacent precast curbs. The joint may be made from, for example, certain type of plastics, composites or metal. 
         [0018]    It is to be noted that although the element composing the constraining means, or joints, have been described as plates in the present document, equivalents having a sufficient rigidity to support the relative movements of and between precast curbs may be used. These equivalents may be, for example, rods, grids, gratings or any other suitable devices. 
         [0019]    The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]    The above and other objects, features and advantages of the invention will become more readily apparent from the following description, reference being made to the accompanying drawings in which: 
           [0021]      FIG. 1  is a perspective view showing a first embodiment of a precast curb. 
           [0022]      FIG. 2  is a perspective view showing a first embodiment of a joint to support and position a precast curb. 
           [0023]      FIG. 3  is a perspective view showing a method to dispose the precast curb of  FIG. 1  in the joint of  FIG. 2 . 
           [0024]      FIG. 4  is a perspective view showing a second embodiment of a precast curb. 
           [0025]      FIG. 5  is a perspective view showing a joint used to install the precast curb of  FIG. 4 . 
           [0026]      FIG. 6  is a perspective view showing a method to dispose the precast curb of  FIG. 4  in the joint of  FIG. 5 . 
           [0027]      FIG. 7   a  and  FIG. 7   b  are side views showing two embodiments used for an entry. 
           [0028]      FIG. 8  is a perspective view showing a precast curb having at least two slots designed for their transport. 
           [0029]      FIGS. 9   a, b  and  c  are perspective views showing three forms of precast curb which may be used for corners or intersections. 
           [0030]      FIG. 10  is a schematic representation of the installation of the precast curb on the ground. 
           [0031]      FIG. 11  is a perspective view showing another embodiment of a precast curb. 
           [0032]      FIGS. 12   a  and  12   b  are perspective views showing still other embodiments of a precast curb having gripping means. 
           [0033]      FIGS. 13   a  and  13   b  are front views showing the embodiment of  FIG. 12 . 
           [0034]      FIGS. 14   a  and  14   b  are respectively a perspective view and a front view of another embodiment of a joint. 
           [0035]      FIG. 15   a  is a front view showing the joint of  FIGS. 14   a  and  14   b  as used with a precast curb. 
           [0036]      FIG. 15   b  is a partial perspective view showing the joint of  FIGS. 14   a  and  14   b  as used with precast curbs. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0037]    A novel precast curb system and method of installation thereof will be described hereinafter. Although the invention is described in terms of specific illustrative embodiments, it is to be understood that the embodiments described herein are by way of example only and that the scope of the invention is not intended to be limited thereby. 
         [0038]      FIG. 1  shows a first embodiment of a precast curb  100  which has a bottom  110 , lateral sides  130  and a steel rod  120 . 
         [0039]      FIG. 2  shows a first embodiment of a joint  200  which may be used with the precast curb  100  of the  FIG. 1 . The joint has a horizontal plate  240  and a first and a second vertical plates  220  and  225  fixed at the lateral edges of the horizontal plate  240 . A third vertical plate  230  extends between the middle of the first and the second vertical plates  220  and  225 . This configuration of the plates defines two spaces  210  and  211 . 
         [0040]    To install the precast curb  100  in situ, two joints  200  are disposed on the ground, which has been preferably prepared as usual for a curb (except that no formwork or in situ casting of concrete is necessary), at a distance corresponding to the length of a precast curb  100 . The extremities of the precast curbs  100  and  101  are inserted in the spaces  210  and  211  of the joint  200 , as shown in  FIG. 3 . Thus, the lateral surfaces  130  of a precast curb  100  are comprise between the first and the second vertical surfaces  220  and  225  and the bottom  110  rests on the horizontal plate  240 . 
         [0041]    In  FIG. 4 , a second embodiment of the precast curb  300  is shown. The precast curb  300  has a bottom  310  and a longitudinal groove  320  on the bottom  310  of the precast curb  300 . A second embodiment of a joint  400  is shown in  FIG. 5 , and is adapted to receive the precast curb  300  of  FIG. 4 . The joint  400  has a horizontal plate  410  and a vertical plate  420 . The installation of the precast curb  300  is similar to the method described before. The joint  400  is disposed on the ground, preferably prepared as usual for a curb, at a distance corresponding approximately to the length of a precast curb  300 . The joint  400  is inserted in two consecutive precast curbs  300  and  301  as shown in  FIG. 6 . 
         [0042]      FIG. 7   a  shows a starting element used to begin the course of the curb with a slope  710  going up gradually to the level  720  of a precast curb.  FIG. 7   b  shows an element creating a passage  760  for vehicles which is preferably at the ground level. As for the starting element, the slope  770  goes up gradually to the level  780  of a precast curb. 
         [0043]    To facilitate the handling of the precast curb, two slots  810  may be molded, as shown in  FIG. 8  to allow a standard lift truck to manipulate them. 
         [0044]      FIGS. 9   a, b  and  c  show the elements used for corners ( 9   a  and  9   b ) and for subdivision ( 9   c ). As seen in  9   a  and  9   b , a corner may have an arcuate form  920  or right angle form  910 . 
         [0045]    The preparation of the ground similar to that of curbs cast in situ. An example is detailed in  FIG. 10 . On one side of the precast curb  990 , the top layer is turf  950 , followed by a layer of top soil  955  and a layer of fill  960 . These layers and the precast curb  990  are disposed on layer of fill  965 . On the paved side, there is the paving  970  on a layer of fill  975  which are disposed on the soil  980 . 
         [0046]    In  FIG. 11 , another embodiment for the precast curb is shown. This precast curb may be used in the same way than the first embodiment for the installation, the joints, the starting element, the driveway element, the slots for the manipulation, the corners elements and the subdivision elements. 
         [0047]    In order to facilitate the displacement and the handling of the precast curb, gripping means are provided as shown in  FIGS. 12   a ,  12   b ,  13   a  and  13   b . Gripping means  990  and  992  allow a gripping tool  998  to hold firmly and lift the precast curb to move it to the desired place. As shown in  FIG. 13   a , the gripping means comprises a recess having a substantially horizontal portion  994 . It is to be noted that the portion  994  is not necessarily horizontal, indeed, this surface is adapted to receive a gripping tool, and thus this surface could be at another angle adapted for particular gripping tool. The portion  996  is rounded in the present embodiment but it could have another profile. The junction between the portion  994  and  996  could be rounded also to minimize crack propagation. 
         [0048]    Referring now to  FIGS. 14   a ,  14   b ,  15   a  and  15   b , there is shown a joint wherein the first plate  850  and the second plate  855  are substantially parallel to their corresponding lateral sides  880  and  882 . 
         [0049]    While illustrative and presently preferred embodiment(s) of the invention have been described in detail hereinabove, it is to be understood that the inventive concepts may be otherwise variously embodied and employed and that the appended claims are intended to be construed to include such variations except insofar as limited by the prior art.