Patent Application
20120131879
1. Field of the Invention
The invention relates to fastening systems and methods used for securing posts and the like to mounting surfaces, and more particularly to post anchoring devices and methods for anchoring wood, fiber or other synthetic composite material posts used in fence, deck, balcony and railing applications to wooden, concrete, fiberglass, vinyl or other surfaces.
2. Description of the Related Art
There is a need to provide a mechanism by which posts can be secured to generally horizontal surfaces in such a way as to meet or exceed the functional requirements of strength and elimination of rot, and at the same time address aesthetic concerns surrounding the visibility and unsightly nature of the anchoring device and the fasteners used therein.
Strength of design is particularly important for an unsupported run of railing or fence posts that separate areas differing in elevation. Equally important is the need to ensure that the end of the post secured to the surface remains dry so that moisture cannot cause rot that will lead to the eventual degradation and destruction of the post.
Providing a solution to these functional and aesthetic concerns has thus far meant that one is achieved at the expense of the other. Superior strength has heretofore only been achieved with devices requiring a fully visible mechanism and fasteners attached to the exterior of the post. Alternatively, superior aesthetic solutions designed to conceal fasteners have heretofore possessed lower strength characteristics and often require unsightly supporting triangular brackets to stiffen the post to surface connection.
Known devices used to secure posts to concrete foundations, retaining walls and surfaces typically resemble a U shaped bracket with an anchoring appendage protruding from the underside of the bracket that is set into wet concrete. These brackets are painted to inhibit rust and require exterior fasteners to secure the post within it. These types of brackets are functional only and not aesthetically pleasing.
Other common forms of known post anchoring devices possess a square or rectangular metal tube with a molded, forged or welded base. The post fits into the tube and is secured by means of either horizontal fasteners through the sidewalls of the tube into the post, or a bracket, which tightens the circumference of the tube around the post. The base is then secured to the mounting surface with bolts or screws all of which are visible. While functional, these devices are not aesthetically appealing.
One known device that is designed to improve aesthetic appearance is a flat square shaped piece of sheet metal, the perimeter of which is slightly larger than the periphery of the cross section of the post. The metal base is fastened to the bottom of the post by screws or bolts passing through the underside of the base and remains concealed when the post is finally secured. The metal base, now attached to the bottom of the post, is then secured to the mounting surface by bolts or screws, through holes at the corners of the exposed periphery of the base, and remain visible.
This device is an aesthetic improvement from the previous devices. However, the corner fasteners are still visible and the strength of the entire union is dependent upon two factors; the holding power of the screw threads in the end grain of the post; and the shear strength of the screw when the post is subjected to lateral and leverage force.
In addition to the above devices, are a number of patented devices for securing posts to mounting surfaces. For example, U.S. Pat. No. 5,568,909 to Timko, U.S. Pat. No. 5,419,538 to Nicholas et al., U.S. Pat. No. 6,015,138 to Kohlberger et al. and U.S. Pat. No. 4,753,420 to Kaaria disclose devices which can be used to attach and secure posts to mounting surfaces.
Timko discloses a mounting bracket consisting of a square base attached to a square receiving tube similar to the known devices described earlier. The Timko device also has two drainage holes at the base of two opposing walls of the receiving tube. The post is placed in the receiving tube and fasteners are screwed, bolted or nailed through openings in the sidewalls and into the post. The base is bolted or screwed to the mounting surface at its corners. While the Timko device provides a stiff, secure union between post and mounting surface, it is attached to the outside of the post and has numerous visible fasteners that detract from the overall aesthetical appearance.
Nicholas discloses a post fastening system whereby the bottom of the post and the mounting surface must be bored in order to accept two separate discs with a threaded center aperture. The discs are screwed separately into the floor surface and the post. The center aperture receives a threaded stud and the post is then secured to the floor by screwing the exposed end of the threaded stud into the opposing disc. While the Nicholas device conceals the fasteners, boring is required in both the post and the floor surface. The system is designed primarily for newel posts used with interior railing systems. The mounting discs and stud are fitted very shallow into the opposing mating surfaces and therefore the union is not as strong as it would be if the stud were to protrude deeper into the post. It is also unsuitable for outdoor applications because the base of the post would be in direct contact with the mounting surface and subject to moisture and water damage.
Kohlberger discloses a newel post-anchoring device for securing newel posts to concrete and elevate the newel post above the surface to protect it from moisture. Although the device does conceal all fasteners, it is not suitable for mounting on to surfaces that are not as hard as concrete, such as wood, because the base is secured by a wedge bolt that must be placed into a hole bored into concrete or like material. The wedge bolt is specifically designed to provide maximum strength in concrete, thus confining the device's application.
Kaaria discloses a railing system, which includes a post anchor device designed to secure and elevate a wood post to a mounting surface without visible fasteners thereby providing superior aesthetics and keeping the wood from contacting water or moisture. The anchor device has a base plate through the center of which is fitted a lag screw from underneath and protruding vertically. The post is pre-drilled to accept the lag screw and is screwed down onto the plate. This device hides all fasteners, but without bracing, the unsupported newel posts are wobbly because the strength of the post to base connection is dependent upon the integrity of the narrow lag screw. The inherently narrow cross sectional dimensions of the lag screw necessarily means that it can never provide the degree of stiffness that is ultimately required for applications outside of a unitary railing system.
In order for exterior posts to withstand exposure to water and moisture, they should be elevated and not placed in direct contact with the mounting surface. Mounting surfaces may be concrete or the like, wood, fiber glass or other composite materials and therefore the ideal fastening mechanism ought to be suitable for each application. Furthermore, the ideal mechanism ought to hide all visible fasteners to maximize aesthetic appeal and yet still provide strength and stiffness so that a single post, or a plurality of posts forming a unitary run of railing or fencing, can stand without supporting brackets.
In addition, a challenge exists for meeting building code requirements for wood posts because the physical properties of wood, such as specific gravity, grain pattern, moisture content and knot locations vary greatly. As a result of this range of variability among wood species, it is not sufficient that a wood guardrail merely meet the lower design loads specified in the building code. Generally, guardrail systems must be tested to be approved in the United States and a safety factor of 2.5 is typically applied. This means that although any guardrail has to be designed to withstand a 200 lbs point load at 36″ (residential) or 42″ (commercial) and also perform with certain deflection limits, it must pass a test where a safety factor of up to 2.5 times is applied in order to gain broad industry acceptance in building code applications. Therefore, a guardrail must surpass a concentrated load of 500 lbs at 36″ or 42″. However even if a single post can not provide load resistance of 500 lbs it does not necessarily mean that a guardrail system using such a post would fail to meet the building code standards. This is because guard rail assemblies are complete systems and dissipate concentrated and distributive load forces among all the various components of the system. Nonetheless, single posts rather than complete post and rail systems are often subjected to this test load as a worst case scenario because it stands to reason that if a single post can with stand such a load, the complete railing system will provide greater resistance—subject of course to rail span limits based on maximum distributive loads created between directional changes. This is a high hurdle to overcome even for posts connected into joist structures with longer resisting arms unless specialized connectors and fasteners are used.
Many academics in the field of wood structures and construction have stated that there are very few methods of connecting a wood post to a deck that will meet the building codes. And none of the methods to which the academics refer as being able to meet the building codes are surface mounted connections between post and deck. Rather the academics refer to configurations where the 4×4 post is set deep into a 2×8 joist structure either on the inside or outside face of the band board or rim joist. When a post is set inside the face of the band board the appearance is improved but more work is required to cut and notch deck boards around the post. In either case many components of heavy gauge deck and joist fasteners are needed to fortify the joist to band board connection because that is where the leverage is directed. This is in addition to the bolts required to directly secure the post to deck.
Aesthetic appearance is equally as important to the marketplace as performance and needs to be addressed. However the aesthetic appearance of a post that is secured to the outside band board does not appeal to many homeowners and architects or builders. The challenge of creating an aesthetically pleasing surface mounted post anchor solution that can come close to traditional connection techniques may be better understood after considering well documented and published studies on joist connected post systems.
One particular study, performed by Professor Joseph Loferski of the Department of Wood Science and Forest Products and Frank Woeste, P. E, Professor Emeritus in the Department of Biological Systems Engineering at Virginia Tech University, entitled “Strong Rail-Post Connections for Wooden Decks”, was reported and published in Journal of Light Construction in February 2005 (the “Virginia Tech study”). The testing was conducted on a 36″ 4×4 pressure treated pine post and it showed that only one design configuration was able to surpass the 500 lbs testing threshold. The design which performed best was a full 4×4 post (no notches) mounted to the band board or rim joist of a 2×8 framed deck structure. The 4×4 post was secured by ½″×6″ carriage bolts and nuts through the post and band board. In addition various combinations of heavy metal joist to band board reinforcing brackets were also used.
There are some important points to note from the tests that were conducted. The deflection limits set by the building code stipulate a maximum deflection for a guardrail system at 200 lbs of force applied at various points along the top of the rail system. The formula is Height of Post divided by 12. A 36″ post would be allowed 3″ of deflection at 200 lbs. The post can deflect further after the 200 lbs threshold but it must still be connected to the deck structure at the 500 lbs limit. All of these specifications can be found in the ASTM document D 7032-08.
The Virginia Tech study focused on the 36″ posts required for residential applications and it showed that with sufficient fasteners for both the post and joist connections, it was possible for a single 36″ post to meet the IRC lateral load safety factor value for a rail system (two or more posts with railing sections between). The results of the test showed that when using the optimal connection configuration, a 36″ post deflected approximately 2″ at 200 lbs—within acceptable limits. It also showed that at 650 lbs, when the test was stopped, the deflection was between 18″ and 24″ but the post to band joist remained connected. This test logically assumed that the most common and likely way to build a wood post connection for use in guardrails was for the post to be set into the joist framework either on the inside of the band board and requiring deck surface boards to be cut and notched around them or as a rather unsightly connection on the outside of the band board. The researchers made no mention of the existing genre of external style surface mounted post anchor devices.
It is worth noting that a post set into and attached to joist framing will virtually always have higher lateral load resistance than a surface mounted anchor system no matter whether the anchor be external or internal to the post. This is because the resisting arm (portion of the joist that the post is attached to is usually longer than what can be offered by aesthetically acceptable surface anchors.
The researchers in the Virginia Tech study demonstrated that the tested single post to joist configuration was sufficient to surpass the stringent IRC recommended test regime ordinarily applied against at least a two post and rail system. However, a large segment of the market, such as homeowners, architects and builders, yearn for a better looking, less laborious, less costly and potentially longer lasting surface mounted wood post anchoring system that can be built into a guard rail application and meet building code requirements. The less desirable aspects of joist connected posts are: decking boards must be notched if posts are set inside the deck framing; when posts are attached to the outside face of deck framing they appear less attractive and require two adjacent posts at exterior corners; railing sections between posts are located beyond the vertical plane of the deck's perimeter which is unappealing and creates a potentially larger gap between the bottom rail and the decking surface; alternatively railing sections can be attached to the inside face of the posts but this creates a crude aesthetic appearance; and wood to wood contact leaves posts and joists vulnerable to water damage in areas with wetter climates leading to faster deterioration and higher maintenance costs.
Surface mounted anchors will almost always offer lower top end lateral load resistance than joist mounted posts, and finding ways to maximize their strength while maintaining their intrinsic aesthetic appeal remained a great challenge in this field of art. Surface mounted anchors offer the benefit of ease and speed of installation as a post is cut to length and inserted or connected to the anchor and then in turn secured to the deck surface or for that matter any other hard surface such as concrete, tile, fiberglass, vinyl. One of the other great benefits of a surface mounted anchoring bracket versus a joist connected post is that in addition to traditional decks, posts can be secured to surfaces where it is not possible to gain access below the surface such as a joist structure. Concrete patios or balconies can be decorated with wood post railings as an example. This is an area in the field of art where joist mounted posts cannot be used and where the consumer has heretofore had no aesthetically satisfying alternative to secure wood posts.
The majority of surface mounted post anchors are external shells which surround the walls of the base of the post. Screws pass through the walls of the anchor into the post. They are large, bulky and unsightly apparatuses which have low aesthetic value. As well, they do not necessarily pass the building code and so their use is most often confined to non-building code applications.
Accordingly, there is a need for a post anchoring device which can be used on a diversity of mounting surfaces, provide greater structural rigidity and strength, minimize or eliminate exposure to moisture, have high aesthetic appeal by concealing the fastening apparatus, and be easy to install.
Accordingly, the present invention provides an apparatus for anchoring a post to a surface comprising a base member capable of being connected to the surface, and an elongate tubular member having a base end and a terminal end, the base end being connected to the base member and the terminal end being remote from the base member such that the post may be impaled upon the tubular member by a user. In some embodiments, the walls of the tubular member at the terminal end are beveled to provide a cutting edge for cutting into the post to facilitate the impalement of the post. The tubular member is preferably cylindrical. In some embodiments, the base member is generally planar, having a first side which faces the surface when the apparatus is attached to the surface, and an opposite second side from which the tubular member extends. The base member may further include a peripheral flange extending away from the plane of the base in the same general direction as the tubular member, the flange having a peripheral edge that is capable of abutment with the end of the post as the post is driven upon the tubular member. In some embodiments, upon the abutment of the end of the post with the flange portion, the base member, flange portion and the bottom end of the post define a cavity in which fasteners or other hardware may be concealed from sight.
The present invention further provides a system for mounting a post to a surface, the system comprising the post anchoring apparatus of the present invention and a post having a cavity at one end to accommodate the tubular member for a close fit therein, the cavity having a cavity length that is less than the length of the tubular member of the apparatus.
The use of a tubular member in the present invention creates a rigid and strong joint at the precise location where most of the leverage and lateral force against a post is concentrated. The tubular member also provides a large surface area for frictional engagement between its inner and outer walls and the material of the post, thereby generating significant frictional holding power. This increased holding power and a more rigid union with the base provides an effective mechanism for mounting a post to a surface in an aesthetically pleasing manner so as to avoid the need for externally visible hardware by enabling the base and fasteners to be installed first and inside the outer periphery of the post walls. This characteristic allows the base to be sized smaller or larger, depending on preference, than the periphery of the post. The combination of the characteristics of this invention as described above offer a superior solution to addressing the challenge of maximizing strength and aesthetic value than prior art devices.
The aforementioned devices alone are useful in many applications and settings because of their much improved aesthetic appearances and holding power. However, to significantly raise the performance of the post to surface connection further, a through-bolt may be provided in some embodiments. Accordingly, in some embodiments, the present invention provides an apparatus for anchoring a post to a surface, the apparatus comprising a base member capable of being connected to the surface, a tubular member that is at least twice as long as it is wide, and having a base end and a terminal end, the base end being connected to the base member and the terminal end being remote from the base member, wherein the terminal end defines an edge capable of piercing into the post to enable the tubular member to being deeply impaled into the post as a result of force applied by a user, and a nut and bolt combination wherein the bolt is adapted to being passed through a hole provided in the post and the tubular member and to being tightened by the nut in a manner that binds together the material of the post and the tubular member.
The present invention also provides a method of anchoring a post to a surface comprising the steps of (a) providing an apparatus comprising a base member adapted to being attached to the surface and a tubular member that defines an inside surface, an outside surface and has a base end and a terminal end, and is at least twice as long as it is wide, wherein the base end of the tubular member is connected to the base member and the terminal end is remote from the base member, and the terminal end defines an edge capable of piercing into the post; and (b) carrying out steps (i) and (ii) in any order: (i) attaching the base member of the apparatus to the surface at a location where the post is to be located; (ii) longitudinally aligning the post with the tubular member, abutting an end of the post to the terminal end and forcing the tubular member into the post to substantially impale the post in a manner that all of the outside surface and all of the inside surface of the tubular member that is within a space defined by the external boundaries of the post are in frictional engagement with the material of the post to secure the tubular member to the post; (c) providing a horizontal hole passing from one side of the post, through the tubular member and out the other side of the post; (d) passing a bolt having a head and a threaded portion through the hole such that some of the threaded portion is exposed; and (e) securing a nut to the exposed threaded portion and tightening the nut such that the nut and the head are snug against the post.
In some embodiments, the method may further include the step of providing a circular cut of the same diameter as the tubular member in one end of the post to accommodate the tubular member therein, the circular cut having a depth that is less than the length of the tubular member; and wherein step (b) comprises: carrying out steps (i) and (ii) in any order: (i) attaching the base member of the apparatus to the surface at a location where the post is to be located; (ii) aligning the circular cut of the post with the tubular member and sliding the post over the tubular member until the terminal end of the tubular member abuts the end of the circular cut, and then forcing the tubular member further into post to substantially impale the post in a manner that all of the outside surface of the tubular member that is within the post, and a portion of the inside surface of the tubular member, are in frictional engagement with the material of the post to secure the tubular member to the post.
In some embodiments, a countersinking recess portion may be provided at each opening of the hole wherein each recess portion is adapted to accommodate either the nut or the head of the bolt such that the nut and the head of the bolt are situated substantially within the perimeter of the post once the nut is tightened. In some embodiments, a suitable filler material may be provided in each recess portion to fill any gap remaining between the nut or the head of the bolt and the respective side of the post so as to provide a smooth, flush finish. In some embodiments, the nut and bolt may comprise a barrel bolt, each having a flattened head portion that fits closely to the sides of the post.
The present invention further provides a system for mounting a post to a surface comprising an apparatus having a base member adapted to being attached to the surface and a tubular member that is at least twice as long as it is wide and having a base end and a terminal end, the base end being connected to the base member and the terminal end being remote from the base member, and the terminal end defines an edge capable of piercing into the post; and a post having a circular cut or cavity at one end to accommodate the tubular member therein, the circular cut or cavity having a cut or cavity depth that is less than the length of the tubular member. In some embodiments, the cut or cavity depth is not greater than two-thirds of the length of the tubular member. In some embodiments, the system may include a nut and bolt combination wherein the bolt is adapted to being passed through a hole provided in the post and the tubular member and to being tightened by the nut in a manner that binds together the material of the post and the tubular member. In some embodiments, the system may include a comprising orienting means for adjusting the longitudinal axis of tubular member relative to the surface.
Only by impaling a hollow tubular member deep inside the post can a vertical anchoring means be completely concealed and still allow for the use of horizontal fastener to pass through it. A post secured by a tubular anchoring device such as the present invention without use of a horizontal fastener may exhibit post splitting and cracking at the point of failure at high horizontal loads, as intimated by the Virginal Tech study. But the presence of a hidden vertical tube permits the optional use of a horizontal fastener that can compress the post anchor and wood fiber together, preventing or minimizing such splitting at higher load values. An advantage of a tubular member is that it is relatively easy to drill a through hole in the post and the tubular member during installation, whereas it is significantly more difficult and certainly impractical to do so with a solid steel member. The bolt passes horizontally through the bottom of the post and through the centre of the tubular member and the entire post about 1″-2″ above the base of the anchor. A nut on the opposite end is secured and binds the post to the wood fiber in and around the tube that is impaled into the core of the post. Under extreme loads, the wood post can no longer split vertically along the grain line because the wide heads of the bolt compress the post material against the tube, thereby substantially increasing the strength and rigidity of the connection when compared to using the anchor without the through bolt. An additional benefit is that the post is not easily pulled up vertically during an up-lift incident, thus making the connection resilient to high velocity winds. In effect, the weakest link in the connection is shifted from the wood post material itself to the strength of the tubular member and base connection.
There are also a number of aesthetic improvements that may be made to the bolt system. The bolt may be designed as a “barrel bolt”” (sometimes referred to as a “Chicago bolt”) with a large diameter and low profile head to spread the holding power and keep the head of the bolt very close to the surface of the post wall. For consistency and clarity, all future references to this kind of bolt will use the term “barrel bolt”. This would allow the many proprietary decorative post sleeves to slide over the post without the bolts heads impeding them.
A barrel bolt differs from a common bolt by virtue of the fact that the nut is not hollow. It has a solid head with a shank that is threaded. This male shank is screwed into a female threaded opening inside the shank of the bolt. When the two pieces are connected the joint is hidden. A barrel bolt may be used with or without a counter bore hole in the post to accommodate each head of the barrel bolt. If a counter bore is used, the head or nut of the barrel bolt may be set inside the periphery of the post wall. A wood plug may be used to cap the counter bore completely concealing the bolt for maximum aesthetic standards.
The use of a tubular member and a horizontal bolt may expand the uses of the device and method beyond just guardrail applications. With larger material specifications the anchor/bolt apparatus and method may have useful application for much larger wood posts installed like single unsupported posts such as light standards, sign posts or mail box posts.
The uniqueness of this apparatus and method of anchoring posts to surfaces is that a horizontal bolt may be used in such a way that the horizontal fastener—the barrel bolt—mates or connects with the vertical anchoring member—a hollow tube—inside the periphery of the post walls and remains completely concealed. Yet the connection of vertical member to horizontal bolt and the performance characteristics mimic those of the bolt connecting to an external vertical anchor located outside the periphery of the post walls.
The present invention addresses the cosmetic demands of the market yet sacrifices none of the strength and performance benefits of the cruder exterior anchoring device offerings in the prior art. It does so by virtue of a vertical tubular member embedded and hidden deep inside the post material yet maximizes the strength and performance benefits of this surface mounted methodology through use of a through bolt or barrel bolt that applies compressive force against opposing walls of the post faces so as to mimic the more crude and visually less appealing technique of a metal shell externally situated around the post against through which a through bolt would also pass but would apply its compressive force against the opposing surfaces of the metal shell. The combination of the hollow vertical embedded tube with the horizontal bolt allow the external shell method to be discarded, greatly improving appearance while still following the general concept of arranging fasteners close to or in direct opposition of reactionary load forces at the bottom of the post that an external system would address.
The preferred vertical member for this kind of installation is a hollow tubular member for a number of important reasons. Firstly, a tubular member may be easily impaled into the post. The post material, be it wood or other similarly dense material, is forced tightly into and around the large surface area of tubular member. The friction holding power is directly proportional to the surface area. Secondly, a tube is a very stiff geometric shape. It is very difficult to bend a tube especially at the union on the base of the anchor. This is precisely where maximum stiffness and strength is required because all of the moments of force on a post are focused at this precise location. The tube is also very light weight as opposed to a solid rod-like member making it more practical to use and manufacture. Thirdly, a tube may be easily drilled through for setting the horizontal bolt. A solid steel member would be very difficult and impractical to use in the field. Fourthly, although the post bottom could be completely bored to accommodate the tube without impaling it into the post, and indeed if extremely dense material such as Ipe or Cumaru hardwoods were used a full bore may be required, it is the presence of post material inside the tube in concert with the horizontal bolt passing through that makes for the optimum union between anchor and post. And fifthly, the orientation of the bolt is optimal: it is aligned in perfect opposition to the forces of load on the post. The post will tend to split apart under extreme load along vertical grain lines even though the material inside the tube will remain firmly held. The bolt is oriented to absorb tensile forces along its longitudinal axis rather than perpendicularly, which means the entire post to anchor connection is able to withstand higher forces. The force required to stretch or pull the bolt apart, and thereby the post, is very large.
After a complete installation, all that is visible is a ⅝″-¾″ (18 mm) diameter head of a bolt protruding an ⅛″ (3 mm) or less from the post wall, depending on the installation technique. The post is thus mechanically connected to the vertically oriented tubular anchor with a horizontal connection means that is functionally similar to the external and visible methods discussed earlier yet visually improved while providing a desired increase in strength.
The tubular anchor device without the horizontal bolt technique provides a great deal of strength by itself and is a substantial cosmetic improvement over the existing genre of external wrap around style anchoring devices. This present invention alone used in guard rail applications has been independently tested and shown to surpass the same building code safety factor (AC 273 and ASTM D 7032-08) standard of 500 lbs end post load, as cited by Virginia Tech study. The addition of the bolt amplifies the performance of a 4×4 SPF (Spruce Pine Fir) post by an average of 26%, also based on independent engineering testing. An additional 26% performance increase is important to many builders or architects as it allows either taller posts with shorter post span spacing or similar posts with longer post span spacing to still resist the minimum load stipulated by building codes. Therefore, the addition of the horizontal bolt with the present invention may be a useful technique to further boost performance beyond the already minimum building code standard while foregoing the heretofore necessity of using more visible and less aesthetically pleasing anchoring means.
The tests with a tubular anchor and bolt system show that the heretofore undiscovered device and method for surface mounting wood posts to decks, balconies, porches and the like, achieves or comes close to providing an ideal solution for surface mounting of wood posts. The amount of hardware required and the time to install the device using this methodology is reduced from the traditional techniques, while at the same time the performance is significantly improved.
The results of the tests conducted on a rail system and method using the device without the horizontal barrel bolt technique have been shown to meet the building code minimum standards for residential guard rails. And other comparative test results that isolate the performance of single posts using the device with and without the barrel bolt confirm increased load resistance with the barrel bolt. Therefore, it is certain that a rail system and method using the device with the barrel bolt will provide an even higher level of performance.
Embodiments of the invention will now be described with reference to the accompanying drawings, in which:
a, 3b, 3c, 3d, and 3e are cross sections of the device in
a and 6b are center cross sections of the device in
Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. The invention disclosed herein may be practiced in embodiments in many different forms. Shown in the drawings and described herein are preferred embodiments of the present invention. However, it is understood that the present disclosure is an exemplification of the principles of the invention and does not limit the invention to the illustrated embodiments.
Referring to
Base member 20 further comprises fastening means such as a plurality of holes 46 disposed proximate to base periphery 48. Holes 46 are adapted to receive fasteners there through, such as screws 50, for the mounting of device 10 to the surface. Preferably, each of the holes 46 comprises a chamfer or counter sunk bore 52 to enable the heads of the screws to be sunk below the top or second surface 54 of the base member upon the installation of the base member to the surface.
One of the more common post sizes in the industry is a 4″ square post, which has an actual width (or diameter in the case of round posts) of approximately 3.5″. In a post anchoring device for use with such posts, length 26 of the tubular member is preferably 3.5″ and width 28 is preferably 1″. The length 26 may be as low as approximately 2″, but the strength of the hold between the tubular member and the post diminishes substantially in proportion to the decrease of the length 26. The length 26 may be longer than the preferable length, but the added benefit in terms of the strength of the hold diminishes as the length 26 increases considering that such increased length means that a greater force will be required to drive the post onto the anchoring device (which increases the risk of deforming the cutting edge, and if the top or remote end of the post is not protected, excessive force can damage it), as well as the increased material costs of manufacture. The width 28 of the tubular member may be smaller or larger than the preferred width. But if too large in proportion to the width of the post, then the remaining holding material 11 of the post may too thin and could fail relatively more quickly, thus compromising the strength of the hold between the tubular member and the post. And if the width is too small relative to the width of the post, then the strength of the hold between the tubular member and the post will be relatively less resistant to lateral forces. For posts of varying sizes, a ratio of the width or diameter of the post to the length 26 of the tubular member is preferably in the range of 0.8:1 to 1.5:1, and more preferably is approximately 1:1. And the ratio of the width or diameter of the post to the width 28 of the tubular member is preferably in the range of 2.4:1 to 5.5:1, and more preferably is approximately 3.5:1. Likewise, while these ratios are described as being preferable, the length 26 and/or the width 28 may be of varying sizes, and similar considerations as above are applicable. Thus, for a given post width (PW), the upper limit of tubular member length (TL) is preferably 1.25 times PW (i.e. the PW:TL ratio is 0.8:1), and the lower limit of TL is preferably 0.67 times PW (i.e. the PW:TL ratio is 1.5:1). Likewise, for any given PW, the upper limit of tubular member width (TW) is preferably 0.42 times PW (i.e. the PW:TW ratio is 2.4:1), and the lower limit of TW is preferably 0.18 times PW (i.e. the PW:TW ratio is 5.5:1). Accordingly, tubular member lengths (TL) may be in the range of 1.6 to 6.9 times the tubular member widths (TW); the upper end of the range of TL:TW is achieved when the highest TL is compared to the lowest TW (i.e. 1.25/0.18=6.9) and the lower end of the range of TL:TW is achieved when the lowest TL is compared to the highest TW (i.e. 0.67/0.42=1.6).
In operation, the post anchoring device is secured to the surface by the fasteners. The post that is to be anchored to the surface is preferably prepared by cutting or boring a cavity or hole 60 into one end to accommodate and guide the tubular member during installation. For example, the hole 60 may be bored using a Forstner bit preferably, or with a spade bit. The diameter of the hole is preferably equal to the outer diameter of the tubular member for frictional engagement between the tubular member and the inner walls 64 of the post. It is possible to use a hole saw of equal diameter to the tubular member and cut a kerf into the post. The depth 66 of the hole or kerf is preferably less than the length 26 of the tubular member, and in particular, is less than the penetration depth 68 of the tubular member for reasons that will be described shortly. A kerf is known in the art to mean a cut made by a saw or the like in a piece of wood. In the present instance, a hole saw (as stated above) is used to cut a circular kerf. Hole saws are well known and typically comprise of a metal cylinder, usually steel, mounted on an arbor adapted to being attached to a rotary drill or the like, and a cutting edge on the cylinder having saw teeth formed in it. A centering drill bit may or may not be present. An example of a hole saw is found in U.S. Pat. No. 4,072,441 to LaPointe. As such, the hole saw cuts a circular kerf into the post, having the same diameter as the tubular member, but leaves a core of the post material within the cut intact. Whenever the term “circular cut” is used herein, it refers to a circular kerf cut by a hole saw, or the like, which leaves a core of material intact within the boundaries of the circular kerf. Referring to
Referring to
Depending on aesthetic preference, it may be desirable that the base member be shaped similarly to that of the post—be it square, rectangular, circular or otherwise. Also depending on aesthetic preference, it may be desirable that the dimensions of the base member be similar to or less than the cross sectional dimensions of the end of the post which is to be mounted on the anchoring device, such that the base is substantially concealed by the mounted post.
Referring to
The base member may be manufactured from plate steel, die case steel, aluminum or other suitable material, and the fastener holes may be machined into the base member. The tubular member may be metal tubing, such as steel or aluminum. The terminal end of the tubular member may be beveled to a single or two-sided cutting edge using a lathe or, preferably, using metal swaging techniques. The base end of the tubular member may be welded to a metal base member. The device can then be coated for corrosion protection using appropriate coating methods.
Referring to
Base member 110 comprises a planar member 130 and flange portions or portion 140 originating along periphery 136 of the planar member and extending away from the planar member such that when the base member is mounted on the surface, the flange portion extends away from the surface. Flange portion 140 terminates in flange edge 144 which is elevated above the mounting surface when the anchoring device is secured to the mounting surface. The planar member 130 further comprises fastening means such as a plurality of holes 148 disposed proximate to periphery 136 for receiving fasteners such as screws 150 there through for the mounting of device 100 to the surface.
To achieve a relatively low cost of manufacture, the base member 110 may be cut or stamped from sheet metal such that the flange portion 140 may be pressed upward to form the solid ridge or flange edge 144 around the periphery of the base. The tubular member 120 may be welded to the base.
In the installation and anchoring of the post, the post anchoring device is secured to the surface by the fasteners and the post is prepared at one end as previously described herein. Referring to
Preferably, the peripheral dimensions of the base member, particularly the flange edge is equal to or less than the cross-sectional dimension of the mounting end of the post, thereby allowing the transverse bottom surface of the post to rest on the upright flange edge 144 and the post walls to extend beyond the periphery of the base when engaged with the device to facilitate the draining of rainwater off the sides of the post and for aesthetic preference. The outer periphery of the walls of the post being greater than the periphery of the base allow for water to drain directly to the mounting surface with no pooling around the bottom edge of the post where the end grain is more likely to absorb surface water.
Also, as described above in the case of a sloped surface, a gasket or shim member 94, as shown in
The base member 110 is preferably sheet metal that is cut or die punched. The sheet metal is cut in such a way that it can be placed on a breaking tool or a custom press so that flanges can be pressed to a generally perpendicular attitude relative to the base. The tubular member is then welded to the base. This method of manufacture is relatively inexpensive, requiring little tooling costs and the resultant device is strong. The device can then be coated for corrosion protection using appropriate coating methods.
Referring to
Base member 410 comprises a planar member 430 and a flange portion 440 originating along periphery 436 of the planar member and extending away from the planar member such that when the base member is mounted on the surface, the flange portion extends away from the surface. Flange portion 440 terminates in flange edge 444 which is elevated above the mounting surface when the anchoring device is secured to the mounting surface. The planar member 430 further comprises fastening means such as a plurality of holes 448 disposed proximate to periphery 436 for receiving fasteners such as screws (not shown) there through for the mounting of device 400 to the surface.
To achieve a relatively low cost of manufacture, the base member 410 may be cut or stamped from sheet metal such that the flange portion 440 may be pressed upward to form the solid ridge or flange edge 444 around the periphery of the base.
The method of attaching the tubular member to the base differs from the previous embodiments. A circular opening corresponding in size to the cross-sectional dimension of the tubular member is provided through the center of the base and the material adjacent the hole is then formed upward from the base to create a raised support portion 450 for supporting the terminal end of the tubular member at a location that is higher up the length than a standard butt joint and weld as described in the other embodiments. The tubular member then fits closely through the opening. When viewed from underneath, there results a circumferential gap 452 between the outer walls of the tubular member and the base where the raised support portion bends away from the plane of the planar member 430 of the base. The circumferential gap 452 is then filled with welding material 455 so that the base and tubular member are welded together from the underside.
The method results in a very clean looking and strong union as a result of the extra thickness of metal surrounding the joint. This extra strength is precisely where the force of the attached post would be directed. This embodiment would be used in a similar manner as described above for embodiments 10 and 100.
Referring to
The most common bolt 230 is a hex headed bolt with the remote end threaded on the exterior surface so that a common nut 234 and optional washers 232 can be installed. This is a less aesthetically pleasing configuration but nonetheless provides a binding mechanism which effectively prevents a wood post from splitting vertically along the grain lines while the post is under extreme lateral load.
A more preferred bolt 236 has a larger diameter and lower profile head 242 for improved aesthetic qualities and for broader holding power than a smaller diameter bolt head. In addition the remote terminus of the shaft of the bolt 236 is threaded internally 244 so that the threaded shaft 246 of the nut 238 can be screwed into it, creating a very strong but a much better looking appearance from both ends. These kinds of nut and bolt combinations are commonly known as “barrel bolts” in the art. Optional washers 232 could also be used with this bolt 236 if desired.
Referring to
Referring to
Plugs can be made using a plug cutter. The plug is cut right from the exact locations on opposing faces of the post where the bolt will pass through. A hole is then drilled through the post and tube perfectly aligned at the centre of the opposing plug cuts. The bolt 230, 236 and nuts 234, 238 are then installed and secured. The plug material can be selected from similar wood to provide an identical or closely matching wood grain and is glued into position completing the installation.
As will be apparent to those skilled in the art various modifications and adaptations are possible in the practice of this invention without departing from the spirit or scope thereof. Accordingly, the scope of the invention is to be construed in accordance with the substance defined by the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2469264 | May 2004 | CA | national |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10981623 | Nov 2004 | US |
| Child | 12426966 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 12426966 | Apr 2009 | US |
| Child | 13364117 | US |
