FIELD OF THE INVENTION
The embodiments of the present invention relate to a joist end cap for use in construction. The joist end caps are designed to eliminate the numerous shortcomings of the prior art joist end caps.
BACKGROUND
Joist end caps are used to prevent moisture from accumulating and seeping into the end of framing lumber. Over time such moisture causes framing lumber to rot thereby causing extensive damage and expensive repair. The repair, consisting of replacing the rotten lumber, may require portions of the subject building to be torn down or otherwise demolished. Therefore, joist end caps have been used to seal the ends of the lumber.
Unfortunately, the current joist end caps suffer from serious drawbacks including improper design and use of materials. Therefore, even though joist end caps are available, they are not reliable and fail to prevent moisture and the associated problems therewith.
Thus, there exists a need for a joist end cap that controls the accumulation of moisture and alleviates the other problems associated with the current joist end caps.
SUMMARY
Accordingly, one embodiment of the present invention is a joist end cap comprising: five walls, consisting of a top wall, bottom wall, two side walls and an end wall, defining a cavity for receipt of an end portion of lumber; and wherein the top and bottom wall are interchangeable and both slanted to permit moisture to flow out of the cavity. In other embodiments, projections on inner surfaces of the walls allow for air circulation and the cap is fabricated of transparent material to permit easy visual inspection.
Other variations, embodiments and features of the present invention will become evident from the following detailed description, drawings and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a perspective view of a joist end cap pursuant to the embodiments of the present invention;
FIG. 2 illustrates a view into a cavity of the joist end cap pursuant to the embodiments of the present invention;
FIG. 3 illustrates an end view of an outside surface of an end wall.
FIG. 4 illustrates a side view of an outside surface of the joist end cap of FIG. 1; and
FIG. 5 illustrates a cross-sectional side view of the joist end cap.
DETAILED DESCRIPTION
It will be appreciated by those of ordinary skill in the art that the invention can be embodied in other specific forms without departing from the spirit or essential character thereof. The presently disclosed embodiments are therefore considered in all respects to be illustrative and not restrictive.
Initial reference is made to FIG. 1 illustrating a perspective view of a joist end cap generally identified by reference numeral 100. More particularly, FIG. 1 shows a joist end cap 100 fabricated of a generally opaque material. However, it should be understood that the joist end cap 100 may also be fabricated of transparent or translucent materials to allow visual inspection as describe below. A cavity 120 formed by top wall 130, bottom wall 140, side walls 150 and an end wall 160 is sized to accommodate an end of a piece of standard lumber used for construction. While a top wall 130 and bottom wall 140 are identified, in some embodiments, the top wall 130 and bottom wall 140 are identical such that the joist end cap 100 may be used in either orientation. As shown in FIGS. 1 and 3, a pattern of projections 110 spaced on outer surfaces of the joist end cap 100 serve to create a space for moisture between timber butting against the outer surfaces of the joist end cap 100. Also, the projections 110 serve to allow the joist end cap 100 to adhere to concrete that may be poured about the outer surface of the joist end cap 100. Whether the outer surfaces of the joist end cap 100 contact timber or concrete depends on the particular structure being built. As shown, the projections 110 are on outer surfaces of the side walls 150.
Now referring to FIG. 2, an inner surface of the end wall 160 includes a pattern of projections 165 and a pair of raised connector (e.g., nail, screw or rivet) guides 170, each surrounded by a raised circular ring 175. While two connector guides are shown, more or less may be used. For reasons stated below, the circular rings 175 include one or more breaks or notches 177. The inner surfaces of the top wall 130, bottom wall 140 and side walls 150 include a series of elongated ribs 180 extending from the inner surface of the end wall 160 to a front edge of cavity 120. The pattern of projections 165 and elongated ribs 180 serve to allow air flow throughout the cavity 120 after it has been fitted onto an end of a piece of lumber. Moreover, the pattern of projections 165 and elongated projections 180 provide means for any moisture to escape from the cavity 120 preventing the lumber from rotting or being otherwise structurally compromised. The projections 165 are angled downward, regardless of the orientation of the joist end cap 100, to permit moisture to congregate at the bottom and flow out as described below. The allowed air flow also facilitates evaporation of any moisture.
Ideally, the connector guides 170 and circular rings 175 have the same height as the projections 165. FIG. 3 shows an outside surface of the end wall 160. A pair of apertures 185 and countersinks 190 correspond to the pair of connector guides 170. Connecting the joist end cap 100 to a piece of lumber is accomplished by fitting the joist end cap 100 over an end of the subject piece of lumber so that the projections 165, connector guides 170 and circular rings 175 come into contact with the lumber. Then, a nail (or screw or rivet) is set through each aperture 185 such that it penetrates a corresponding connector guide 170 and enters the lumber. The countersink 190 provides a location for a nail (or screw or rivet) head to reside flush with the outer surface of the end wall 160. Being the same height as the projections 165, the connector guide 170 and circular rings 175 prevent the end wall 160 from indenting adjacent to the nail being set. Consequently, the head of the nail rests in the countersink 190 providing a relatively watertight barrier preventing moisture from entering the cavity 120. Should any moisture invade the cavity 120 adjacent the nail setting, the breaks 177 in the circular rings 175 provide an avenue for the moisture to move to an inner surface of the bottom wall 140. A break 177 on either side of the circular rings 175 allows moisture to flow down no matter which way the joist end cap 100 is installed. Without the raised connection guides and circular rings 175, setting the nails could cause the end wall 160 to indent near the nail settings and potentially cause cracks or other avenues for moisture to invade the cavity 120. Indentations would be possible given the pattern of projections 165 on the inner surface of the end wall 160 and the likelihood that carpenters would vigorously set the nails or other connection devices.
FIG. 5 shows a cross-sectional side view of the end joist cap 100. The top wall 130 and bottom wall 140 include the series of elongated ribs 180. The top wall 130 and bottom wall 140 are sloped from the end wall 160 to a front edge thereof. The slope is downward creating an angle (A) with a horizontal line as defined by an upper edge of the elongated ribs 180. The slope ensures that any moisture which may collect in the cavity 120 flow outs of the cavity 120. As the joist end cap 100 is symmetrical, either end may act as the top or bottom and therefore both are sloped. Alternatively, the joist end cap 100 may include labels identifying the top wall and bottom wall such that only the bottom wall is sloped. Such an embodiment also requires only one notch or break 177 in the circular rings 175 wherein the notch or break 177 is directed toward the identified bottom wall 140. With the slope of the top and bottom walls 130, 140, the elongated ribs 180 on the inner surfaces of the top and bottom walls 130, 140 slope in an opposite manner to maintain a flat surface, along the elongated ribs 180, for constant contact with a piece of inserted lumber along the length of the top and bottom walls 130, 140.
Suitable materials for fabricating the joist end cap 100 should, at a reasonable cost, be able to handle the load and temperature ranges (−40° C. (−40° F.) and 50° C. (122° F.)) encountered by the joist end caps while remaining watertight. The inventors have found through extensive private experimentation that Poly Vinyl Chloride (PVC), Polyethylene Terephthalate (PET) and Polypropylene (PP) are ideal materials in light of the desired criteria (i.e., load, temperature and cost). They are also capable of being transparent or translucent. When tested, the aforementioned materials were able to handle load bearing stresses above 2500 pounds while other products on the market are only able to handle 880 pounds to 1825 pounds. It will be understood by those skilled in the art that other materials, depending on the actual loads and temperatures, are suitable as well.
Although the invention has been described in detail with reference to several embodiments, additional variations and modifications exist within the scope and spirit of the invention as described and defined in the following claims.
Patent Application
20080110121
