Abstract:
An anchoring system for securing an elastomeric membrane to the upper surface of a roof has a rigid anchoring plate which has a planar bottom surface, apertures to facilitate securing the anchoring plate to the roof, and a pair of raised reinforced sidewalls to aid in interlocking the device. A spacing insert is provided which employs a pair of flanges, a pair of horizontal lips, and a central hinge to snap into the anchoring plate after the membrane has been load out over the anchoring plates. A planar wedge is also provided which includes a lip to facilitate inserting the wedge into, and withdrawing the wedge from, the spacing insert. When the components of the present anchoring system are fitted together, an elastomeric membrane may be substantially immobilized. The structure of the device is also easily disassemblable, as may become necessary in order to inspect or service the elastomeric membrane.

Description:
FIELD OF THE INVENTION 
     This invention relates to an apparatus for attaching an elastomeric roofing membrane to the top surface of a roof, and more particularly to an apparatus which is capable of securing a roofing membrane without penetrating the same. 
     BACKGROUND OF THE INVENTION 
     The traditional method used to protect roofs from rain and other forms of inclement weather was to lay down several layers of material, normally felt soaked with bitumen, thereby building up a waterproof membrane. This method has several problems; the process is very long and susceptible to contamination by rainwater or other foreign materials. Furthermore, the bitumen must be heated to the point where it gives off noxious odors. 
     In recent years, alternate systems using elastomeric membranes have become increasingly popular. A suitable elastomeric membrane is laid over the top surface of the roof itself, or more preferably, an insulation board. A variety of methods for fastening the elastomeric membrane to the surface of the roof have also been developed. One method is to spread an adhesive over the entire surface of the roof before laying down the membrane. This process is very labor-intensive and requires that the installers be exposed to adhesives giving off noxious fumes. 
     Alternatively, the membrane can be fastened to the roof mechanically. Several devices have been developed which require that a nail or screw be allowed to penetrate the membrane. This can lead to tears and rips in the membrane, especially as the membrane expands and contracts in response to changes in the ambient temperature. These breaches in the integrity of the membrane in turn can lead to water leakage and eventual damage to the underlying roof. 
     A variety of other devices have also been developed which are capable of securing a membrane to the upper surface of a roof without penetrating the membrane. The applicant believes that the following references are illustrative of the non-penetrating anchoring systems which have been patented. 
     
         ______________________________________U.S. Pat. No.       Patentee______________________________________4,519,175           Resan4,617,771           Tomaszewski4,624,092           Baginski4,631,887           Francovitch4,658,558           Verble______________________________________ 
    
     U.S. Pat. No. 4,519,175 issued to Resan discloses a three-piece fastening apparatus wherein the roofing membrane is laid over the bottom piece and then a second tined piece is clipped over the membrane and the protruding boss of the bottom piece. The top piece of the device is then screwed onto the second piece thereby locking the device together and securing the membrane. 
     U.S. Pat. No. 4,617,771 issued to Tomaszewski discloses a three-piece fastening system which snaps together. The device includes an elastic ring which provides tension when a top piece is snapped into the bottom piece. 
     U.S. Pat. No. 4,624,092 issued to Baginski discloses a two-piece fastening system which snaps together. The bottom piece of the device serves as the male element; the membrane is laid over the bottom piece, and a collar is snapped over the top of the bottom piece. This device, however, allows the area of the membrane directly over the bottom piece to be exposed to the atmosphere. 
     U.S. Pat. No. 4,631,887 issued to Francovitch discloses a three-piece fastening system which snaps together. In the use of this device, a second piece is inserted inside of the bottom piece which helps maintain the tension produced when the top, or cap piece is snapped over the membrane and the protruding boss of the bottom piece. 
     U.S. Pat. No. 4,658,558 issued to Verble discloses a two-piece fastening system which snaps together. In this device, the bottom piece serves as the female piece. The bottom piece is attached to the top surface of the roof, the membrane is laid out, and the top piece is snapped into the bottom piece, thereby locking the device together and securing the membrane. 
     These devices are all capable of securing an elastomeric membrane to the upper surface of a roof without penetrating the membrane; however there are several limitations and suboptimizations inherent in these devices and the prior art in general. 
     First and foremost, the way in which previously-disclosed devices generate the restraining force necessary to secure the membrane to the roof creates problems. For example, devices which screw together, such as the device disclosed by Resan in U.S. Pat. No. 4,519,175, carry with them the danger that the device will be over-tightened, thereby straining or even ripping the membrane. Alternatively, devices which screw together may be undertightened, allowing the top, or cap piece of the device to work its way loose. 
     Devices which utilize the thickness of the membrane itself to generate the majority of the restraining force used to hold the device together, and hence, anchor the membrane to the roof have other problems associated with their use. Devices such as those disclosed by Verble in U.S. Pat. No. 4,658,558 and Francovitch in U.S. Pat. No. 4,631,887, in essence, call for the installer to provide the wedging force necessary to either push a cap over a protruding boss, as in the case of Francovitch, or to push a plug into a housing, as in the case of Verble. These types of devices can stretch and fatigue the membrane, increasing the risk that a rip will form which allow water to pass through the membrane and damage the underlying roof structure. Furthermore, fastening devices which employ the thickness of the membrane itself to supply the majority of the tensional force necessary to keep the device locked together have very little margin for error. For example, the calender seams formed where two sheets of the roofing membrane are joined together are often too thick to fit into these types of devices. This can lead to either the necessity for careful pre-planning of the placement of the devices or wastage of those bottom pieces which are installed too near a calendar seam. Also, devices of this type which utilize base plates which are basically circular may give rise to a large number of irregularly-distributed wrinkles which give the impression of a slovenly installation. 
     A second major problem with the devices disclosed by the existing patents is the difficulty in servicing these devices. After a elastomeric membrane has been installed on a roof, it may become necessary to inspect the membrane for a variety of reasons; for example when a water leak is discovered inside the underlying structure. With the previously-patented fasteners, it is almost impossible to disassemble the fastening system without damaging both the device and the membrane. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is among the objects of this invention to remedy the foregoing disadvantages by providing an improved non-penetrating anchoring system wherein the device itself supplies the majority of the locking force necessary to keep the device interlocked and the elastomeric roofing membrane stable. 
     A second object of the present invention is to provide a non-penetrating anchoring system which can be serviced easily and without damage to either the device or the elastomeric membrane. 
     A further object of the present invention is to provide a non-penetrating anchoring system which cannot be either over- or under-tightened. 
     A further object of the present invention is to provide a non-penetrating anchoring system which can accommodate a variety of different types of elastomeric membranes as well as the calender seams formed where two sheets of elastomeric membrane are joined. 
     A further object of the present invention is to provide an economical system for attaching an elastomeric roofing membrane to an existing structure without the use of special tools or extensive modification of the existing structure. 
     These and other objects and advantages will become more apparent from the following detailed description taken in conjunction with the illustrative drawing figures, and the novel features thereof will be defined in the appended claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded view of the present invention showing the relative positioning of the anchoring plate, spacing insert and insert wedge components thereof. 
     FIG. 2 is a perspective view showing the constituent components of the present invention assembled, and in the process of securing an elastomeric membrane. 
     FIG. 3 is an elevational view of an alternate assembly of the present invention in cross-section showing the spacing insert being inserted within the anchoring plate. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawings wherein like numbers refer to like elements throughout, the anchoring system 10 includes, in general, an anchoring plate 20, a spacing insert 40, an insert wedge 60, and fastening means 70. 
     The anchoring plate 20 is rigid and, as is best shown in FIG. 1, includes a planar bottom 21 which can include cutouts to reduce the total weight of the device (not shown). The anchoring plate 20 is rectangular in shape, having two shorter sides 22 and 22&#39; and two longer sides 23 and 23&#39;. Two sidewalls 24 and 24&#39; are disposed along the two longer sides 23 and 23&#39; of the anchoring plate 20. The side walls 24 and 24&#39; each have a horizontal lip 25 which extends inwardly over the top planar surface 26 of anchoring plate 20. 
     The anchoring plate 20 is provided with a plurality of apertures 27 to facilitate securing the anchoring plate 20 to the top surface of a roof (for example by a screw or other fastening means 70) (in FIG. 1, three apertures 27 are shown, but clearly a different number of apertures could be utilized). As shown in FIG. 3, the apertures 27 are counterbored to allow the fastening means 70 to be tightened down to the point where the heads of the screws are beneath the top planar surface 26 of the anchoring plate 20, thereby assuring that the membrane 90 will not be abraded by the tops of the fastening means 70. 
     The anchoring plate 20 also includes a plurality of triangular braces 28 which are mounted perpendicularly to, and outside of, each of the side walls 24 and 24&#39; (in FIG. 1, five triangular braces 28 are shown, but clearly a different number of braces could be utilized). The triangular braces 28 are mounted on the anchoring plate 20 in such a way that a first side 29 runs along the top surface 26 of the anchoring plate 20 and a second side 30 runs along the height of the sidewalls 24 and 24&#39;. These two sides 29 and 30 of the triangular braces 28 are by definition perpendicular to each other. Hence, the hypotenuse 31 of each triangular brace 28 runs from the outside edge of one of the longer sides 23 and 23&#39; of the anchoring plate 20 to the top outside edge of the sidewalls 24 and 24&#39;; in other words, to the point where the sidewalls 24 and 24&#39; intersect with the horizontal lip 25. 
     The second component of the anchoring system 10 is a spacing insert 40. The spacing insert 40 has a planar bottom surface 41 and top surface 42. Like the anchoring plate 20, the spacing insert 40 is rectangular in shape, having two longer sides 43 and 43&#39; and two shorter sides 44 and 44&#39;. A pair of vertical flanges 45 and 45&#39; are disposed parallel to the longer sides 43 and 43&#39; of the spacing insert 40. The flanges 45 and 45&#39; are positioned near, but not at, the outer edges of the spacing insert 40. 
     Each of the flanges 45 and 45&#39; has a lip 46 mounted on it&#39;s top. The lip 46 is parallel to the planar top surface 42 of the spacing insert 40 and extends both inwardly and outwardly from the flange 45 and 45&#39;. The exterior portion of each lip 46 extends out beyond the edge of the two longer sides 43 and 43&#39; of the spacing insert 40, and when considered in conjunction with the exterior face of the flanges 45 and 45&#39; and the portion of the top surface 42 of the spacing insert 40 outside of the flanges 45 and 45&#39; forms a C-shaped notch 47 and 47&#39;. 
     The portion of the lips 46 which extends inwardly from the flanges 45 and 45&#39;, when taken in conjunction with the portion of the planar top surface 42 of the spacing insert 40 which is disposed between the two flanges 45 and 45&#39; forms a substantially rectangular shaped cavity 48, into which the insert wedge 60 is inserted, conforming to the configuration of the flanges 45 and 45&#39; of the spacing insert 40 and thereby providing sufficient rigidity to the device to provide an anchoring system 10 capable of securely fastening an elastomeric membrane 90 to the top surface of a roof. 
     The spacing insert 40 also includes a hinge 49 which is disposed parallel to, and midway between, the flanges 45 and 45&#39;. In the preferred embodiment, as is best shown in FIG. 1, the hinge 49 is a groove which runs from one of the shorter sides 44 of the spacing insert 40 to the other short side 44&#39;. As is best shown in FIG. 3, this hinge 49 provides a line of flexure along which the spacing insert 40 can be flexed to aid in inserting the spacing insert 40 within the anchoring plate 20. 
     The third major component of the present anchoring system 10 is an insert wedge 60. The insert wedge 60, like the spacing insert 40 and anchoring plate 20 is preferably formed of substantially rigid plastic. The insert wedge 60 has a planar bottom member 61 which can be inserted within the substantially rectangular shaped cavity 48 of the spacing insert 40 as will be more fully described hereinafter. 
     Finally, the anchoring system 10 utilizes appropriate fastening means 70, such as screws or bolts, to secure the anchoring plate 20 to the upper surface of a roof. 
     OPERATION 
     The first step in assembling and utilizing the present anchoring system 10 (disregarding those steps necessary to prepare the upper surface of a roof for installation) is to fasten the anchoring plate 20 to the surface of a roof. As is shown in FIG. 3, this can be done by inserting screws 70 through the apertures 27 in the top surface 26 of the anchoring plate 20. It is important that the fastening means 70 be fully tightened down in order that the membrane 90 not be abraded by the tops of the fastening means 70. As is best seen in FIG. 3, the apertures 27 are formed in such a way that the fastening means 70 can be counterbored beneath the top surface of the anchoring plate 20. 
     The next step in utilizing the anchoring system 10 of the present invention is to spread the elastomeric membrane over the upper surface of the roof, and hence, the anchoring plates 20. As will be more fully discussed hereinafter, the thickness of the membrane at those places where it overlays the anchoring plate 20 determines the way in which the spacing insert 40 is positioned within the anchoring plate 20. For example, at the calender seams formed where adjacent rolls of elastomeric membrane are joined together, the effective thickness of the membrane will be twice as great as in places where anchoring plates 20 have been positioned beneath the middle of a sheet of the membrane 90. Furthermore, in some situations, for example in high-wear installations, it may be desirable to utilize a heavier than normal membrane; for example 60 mils instead of the normal 45 mil membrane. 
     For example, the relative positioning seen between the anchoring plate 20 and spacing insert 40 in FIG. 3, i.e., with the lips 46 above the upper planar surface 41 of the spacing insert 40, would be utilized to secure relatively thicker portions of the membrane 90 (e.g. calendar seams in thin membranes, which are normally 90 mils thick or thicker membranes which are normally 60 mils thick). This configuration is used in this context because the lips 46 attached to the tops of the flanges 45 and 45&#39; extended outwardly (i.e. away from the central hinge 49) further than the two longer sides 43 and 43&#39; of the spacing insert 40. 
     The relative positioning shown in FIG. 2, on the other hand, (i.e. with the lips 46 of the flanges 45 and 45&#39; positioned below the top planar surface 41 of the spacing insert 40) is utilized where a relatively thinner section of membrane 90 has been positioned over the anchoring plate 20 (e.g. a single thickness of membrane, which usually has a thickness of approximately 45 mils). Since the two longer sides 43 and 43&#39; of the spacing insert 40 do not extend outwardly as far as the lips 46 mounted at the ends of the flanges 45 and 45&#39;, the configuration shown in FIG. 2, wherein the lips 46 are inserted beneath the horizontal lips 25 of the anchoring plate 20, exerts more pressure on the elastomeric membrane, and hence generates more retaining force than the configuration shown in FIG. 3, wherein the two longer sides 43 and 43&#39; of the spacing insert 40 are inserted beneath the horizontal lips 25, 25&#39; of the anchoring plate 20. 
     In either configuration, the insertion of the spacing insert 40 within the anchoring plate 20 is made possible by the hinging action of the spacing insert 40. The hinging action of the spacing insert 40, is in turn made possible by the central hinge 49 of the spacing insert 40. In FIG. 3 the hinge 49 is shown as a groove within the top planar surface 42 of the spacing insert 40, running from one of the two shorter sides 44 and 44&#39; to the other, but as will be appreciated by those skilled in the relevant art, other mechanisms could be employed. 
     Once the spacing insert has been snapped into place by applying pressure along the hinge 49, as is shown in FIG. 3, the horizontal lips 25 of the anchoring plate 20 will fit within the C-shaped notches 47 and 47&#39; formed as part of the spacing insert 40 by the portion of the lips 46 extending outwardly from the flanges 45 and 45&#39;, taken in conjunction with the outer face of the flanges 45 and 45&#39;, and the portion of the top planar surface 42 of the spacing insert 40 outside of the flanges 45 and 45&#39;, in a tongue-and-groove fashion which is capable of reliably securing and immobilizing the elastomeric membrane 90 within the anchoring plate 20. 
     In either configuration, that is, when the substantially rectangular shaped cavity 48 of the spacing insert 40 is pointed either upwardly or downwardly, the final step in utilizing the present anchoring system 10, is to insert the insert wedge 60 within the substantially rectangular shaped cavity 48 of the spacing insert 40 and thereby interlock the components of the anchoring system 10 in a secure fashion. The insert wedge 60, therefore, is inserted into the substantially rectangular shaped cavity 48 in such a way that the bottom member 61 of the insert wedge 60 becomes positioned between the bottom of the flanges 45 and 45&#39; and the top planar surface 42 of the spacing insert 40, as is seen in FIG. 2. The orientation of spacing insert 40 within the anchoring plate 20 depends upon the configuration--that is, with the flanges 45 and 45&#39; pointing up, as is shown in FIG. 3, as is used with thicker portions of the membrane 90; or with the flanges 45 and 45&#39; pointing down, as is shown in FIG. 2, as is used with thinner portions of the membrane 90--the insert wedge 60 is positioned in the same basic fashion, i.e., with the bottom member 61 inserted between the flanges 45 and 45&#39; and the top planar surface 42 of the spacing insert 40. 
     The insertion of the insert wedge 60 within the substantially rectangular shaped cavity 48 of the insert wedge 40 is facilitated by a lip 62 disposed perpendicularly to the bottom member 61. The lip 62 can be, for example, hit by a mallet, or kicked gently by a worker&#39;s boot, in order to drive the insert wedge 60 into the substantially rectangular shaped cavity 48 of the spacing insert 40. 
     The process of disassembling the present anchoring system 10, as may become desirable in order to inspect or repair the membrane 90, is similarly easy to accomplish, and is begun by using a mallet to drive the insert wedge 60 out of the substantially rectangular shaped cavity 48 of the spacing insert 40. 
     The foregoing description of the preferred embodiment of the present invention is to be considered as illustrative only. Furthermore, since numerous modifications and variations will readily occur to those skilled in the relevant art, it is not desired to limit the scope of the present invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents which fall within the scope of the claims may be resorted to.