Patent Application
20110014010
1. Field of the Inventions
Embodiments disclosed herein relate to hardware used to fasten one or more layers of roofing material, for example, metal roofing panels, to an underlayment, for example, a wooden roof and/or a roofing membrane and methods for making such fasteners. For example, certain embodiments include washers having a deformable vulcanizate sealing layer.
2. Description of the Related Art
Roofing panels or layers, for example metal panels, can be fastened to an underlayment, for example, wood and/or a roofing membrane layer, using threaded fasteners. In some cases, roofing washers may be used with common sandwich panel style construction used in harsh climates where additional insulation is required. In such cases, two layers of trapezoidal or corrugated metal panels are held together with an insulating material disposed between the two panels. The insulating layer can be between about 6 and about 10 inches.
In many cases, roofing washers are used to distribute the load from the threaded fastener over an area of the roofing panel that is larger than the head of the fastener. Existing roofing washers can include a backing layer and a sealing layer disposed opposite to the backing layer. The sealing layer can engage the roofing panel and be configured to form a partial seal around the aperture in the roofing panel that receives the stem or shank of the fastener. The seal formed between the washer and the roofing panel can prevent the ingress of liquid or particulate matter therethrough and/or minimize heat transfer through the seal. Accordingly, the seal between a roofing washer and a roofing panel can be important to protect the integrity of the underlayment and/or structure contained below the roof
Existing roofing washers include sealing layers comprising rubbers or polymers, for example, uncured ethylene propylene diene M-class rubber (“EPDM”). These materials can form a seal between the washer and roofing panel when the fastener is initially tightened to the underlayment.
The devices and methods of this disclosure each have several aspects, no single one of which is solely responsible for their desirable attributes. Without limiting the scope of the claims, some prominent features will now be discussed briefly. After considering this discussion, and particularly after reading the section entitled “Detailed Description of Certain Embodiments,” one will understand how the features of the devices and methods disclosed herein provide advantages over other known devices and methods.
An aspect of at least one of the inventions disclosed herein includes the realization that curing a sealing layer of a washer can overcome certain problems. For example, existing sealing layers can have limited memory or recovery characteristics. Over time, the roofing panel can expand and contract in response to temperature changes and existing sealing layers can not move along with the panel resulting in gaps or voids in the seal. Existing sealing layers can also pull away from the washer backing and/or the roofing panel as the panels expand and contract.
Furthermore, the sealing layers used in existing washers cannot be powder coated because of the effects of high temperature on the materials. This creates inefficiencies in manufacturing roofing washers because the backing layers must be powder coated before the sealing layers are adhered to the backings and individual washers with sealing layers cannot be powder coated. Instead of producing a large quantity of washers and later powder coating a smaller batch of individual washers, the backing material has to be carefully measured, powder coated, and stamped before adhering the sealing layer to the stamped backing layers.
Sealing layers that cannot be powder coated can also present aesthetic concerns for users because the sealing layers can be differently colored than the backings. Backing layers with sealing layers adhered thereto can be individually painted using solvent based techniques. However, solvent based techniques are disfavored in environmentally friendly countries, for example, many countries in Europe.
Thus, in accordance with at least some of the embodiments disclosed herein, a washer is provided with a vulcanized sealing layer. By providing a washer with a vulcanized sealing layer, such a washer can be formed into its final shape, with the sealing layer attached, then further finished. For example, a finished washer with a contoured stamped rigid body and a vulcanized/cured sealing layer can be powder coated without destroying the sealing layer.
In accordance with other embodiments, a roofing washer can be used with a fastener having an elongated stem and a head at one end of the stem. The head can have an outer diameter that is greater than an outer diameter of the stem. The roofing washer can include a rigid backing layer configured to engage at least a portion of the fastener. The backing layer can have an aperture formed therein for receipt of at least a portion of the stem. The roofing washer can also include a deformable layer disposed on at least a portion of the backing layer. The deformable layer can have an aperture formed therein for receipt of at least a portion of the stem. The deformable layer aperture can be generally aligned with the backing layer aperture and the deformable layer can comprise a vulcanizate.
In accordance with other embodiments, a method of manufacturing a washer is disclosed. The method can include providing a generally planar uncured elastomer layer having a first surface and a second surface opposite the first surface. The method can also include providing a generally planar rigid backing layer and disposing the second surface of the uncured elastomer layer on the backing layer. The method can comprise vulcanizing the uncured elastomer layer to produce a vulcanizate layer disposed on the backing layer.
According to other embodiments, a washer can comprise a metallic backing layer having an aperture formed therein for receipt of at least a portion of an elongated threaded fastener. The elongated threaded fastener can have a stem and a head at one end of the stem. The washer can also include a memory foam layer having an aperture formed therein for receipt of at least a portion of the threaded fastener. The memory foam aperture can be generally aligned with the metallic backing layer aperture and the memory foam layer can be generally deformable. The washer can also include an adhesive layer disposed between at least a portion of the metallic backing layer and the memory foam layer.
Embodiments disclosed herein relate to roofing washers used with threaded fasteners to secure roofing panels to an underlayment and methods of manufacturing the same, although the present inventions are not limited to this preferred application. Roofing washers can include a backing layer that a fastener head can be seated against and a sealing layer configured to conform to the roofing panel surface to form a seal between the fastener(s) and the roofing panel. Existing sealing layers comprise uncured or cured elastomers or rubbers with undesirable memory or hardness characteristics. The use of these materials in existing roofing washers presents problems with the integrity of seals over time, with manufacturing efficiency, and with aesthetics.
To address the limitations in current roofing washers, new washers and methods of making washers are described herein that incorporate a deformable sealing layer comprising a vulcanized material (“vulcanizate”). Vulcanization refers to a curing process where heat and pressure are applied over time.
When vulcanizing elastomers, heat and pressure are used to cross-link polymer molecules by atomic bridges. In some cases, a foaming agent or blowing agent can be used during the vulcanization process. A foaming agent can be added to or infused with an elastomer and decompose when heat and pressure are applied resulting in the evolution of nitrogen, carbon monoxide, carbon dioxide, and/or ammonia gases which are trapped in the elastomer to form a foamed article.
Decomposed gas can be allowed to expand controllably within the elastomer to produce foams with desirable cell sizes by achieving an optimum level of tensile properties at elevated temperatures by cross-linking the polymer molecules. Vulcanizates have many desirable characteristics including limited absorption of water, resistance to heat, resistance to ultraviolet radiation, resistance to chemicals, and memory.
Roofing washers incorporating a deformable vulcanizate layer can address sealing limitations in existing roofing washers stemming from the limited memory of existing sealing layers. One such limitation arises when roofing panels expand and contract due to changes in temperature. To maintain a proper seal between the fixed fastener head and the moving roofing panel, the sealing layers in roofing washers must expand when the roofing panels contract and contract when the roofing panels expand.
Roofing washers incorporating a vulcanizate layer can also address manufacturing limitations in existing roofing washers stemming from the inability to powder coat certain elastomers, for example, certain cured foamed elastomers. To provide flexibility in manufacturing batches of washers of various quantities and colors, it is desirable to manufacture a large quantity of un-painted washers and then powder coat any number of washers to match the requirements of a particular order. Powder coating requires high temperatures and thus, certain elastomers, for example, cured foamed elastomers, cannot be powder coated without damaging the elastomer layer. Therefore, existing manufacturing processes require a manufacturer to measure out a certain amount of backing material, stamp and powder coat the backing material, and then adhere sealing layers to each stamped piece of backing material to produce a finished washer. Embodiments disclosed herein can remedy the sealing and manufacturing limitations that exist with existing roofing washers by using a deformable vulcanizate material as the sealing layer.
Embodiments are described below with reference to the accompanying Figures, wherein like numerals refer to like elements throughout. The terminology used in the description presented herein is not intended to be interpreted in any limited or restrictive manner, simply because it is being utilized in conjunction with a detailed description of certain specific embodiments of the invention. Furthermore, embodiments of the invention can include several novel features, no single one of which is solely responsible for its desirable attributes or which is essential to practicing the inventions herein described.
In some embodiments, at least one aperture 116 can be formed through at least a portion of the washer 100. As shown in
For example, in some embodiments the aperture 116 can be configured to receive a fastener shank having a diameter of about 0.25 inches and the aperture can be sized to be slightly larger than about 0.25 inches. As shown in
The size of the washer 100 can vary depending upon the intended application for the washer. In some embodiments, the size of the washer can depend on the size of the fastener shank the washer 100 is configured to receive. For example, in some embodiments, a washer 100 can be configured to receive a fastener having a shank or stem with a diameter of about 0.25 inches and the minimum width of the washer 100 must be greater than at least about 0.25 inches. In some embodiments, the size of the washer 100 can depend on the size of the fastener head.
Washers 100 can be generally configured to distribute a load from a fastener head over an area that is larger than the area of the fastener head. Accordingly, washers 100 can be sized depending on the size of the intended fastener head, the intended load to be distributed, the surface the washer 100 is configured to engage, and/or the size of the fastener shank.
As shown in
In other embodiments, the seating portion 114 can be configured to engage another washer disposed between the roofing washer 100 and a fastener head. The shape and size of the seating portion 114 can be chosen based on the size and/or shape of the surface the seating portion 114 is configured to engage. In some embodiments, the shape of the seating portion 114 can facilitate a generally uniform distribution of a load from a fastener head across an area defined by at least a portion of the washer 100.
In some embodiments, roofing washers 100 can include one or more reinforcing ribs or members 112 configured to provide strength and/or support to the washer 100. Reinforcing ribs 112 can reduce the amount of backing material required to produce a washer 100 by reinforcing the backing in critical areas or along certain directions. The quantity, size, shape, and locations of reinforcing ribs 112 can vary. In the illustrated embodiment, the washer 100 includes two reinforcing ribs 112 disposed generally parallel to one another on opposite sides of the aperture 116. However, in other embodiments, different configurations can be employed to provide support and strength to a washer 100.
The backing layer 110 can be made out of various materials. Examples of suitable materials include, but are not limited to, composite materials, aluminum, stainless steel, brass, copper, silicone bronze, bronze, galvanized steel, monel, zinc, other metals, and combinations thereof The thickness of the backing layer 110 can vary. In some embodiments, the thickness can be between about 0.015 inches and about 0.125 inches. The thickness of the backing layer 110 can vary across the washer 100. For example, the thickness of a reinforcing rib 112 can be greater than the thickness of the backing layer 110 at another location.
The sealing layer 120 can be made out of various materials. Examples of suitable materials include, but are not limited to, foams, cured polymers, cured elastomers, cured rubbers, vulcanized elastomers, vulcanized polymers, other vulcanizates, and combinations thereof The sealing layer 120 can be formed by vulcanizing a starting material that is infused with or contains a suitable foaming agent. Examples of suitable starting materials include, but are not limited to, EPDM, neoprene, uncured rubbers, elastomers, and/or blends of polymers. In some embodiments, blends of olefinic polymers can be used as starting materials to formulate suitable foamed vulcanizates. Examples of suitable blends of olefinic polymers include, but are not limited to substantially linear poly(ethylene-co-1-octene)/substantially linear poly (ethylene-co-1-propene) blends, linear poly(ethylene-co-1-octene)/substantially linear poly(ethylene-co-1-butene) blends, linear poly(ethylene-co-1-octene)/linear poly(ethylene-co-1-hexane) blends, substantially linear poly(ethylene-co-1-octene)/poly(ethylene-co-vinylacetate) blends, and linear poly(ethylene-co-1-octene)/poly(ethylene-co-vinylacetate blends. Suitable olefinic blends used as starting materials can also contain minority amounts (<50 wt percent based on the weight of the blend) of scission-prone polymers, for example, polypropylene.
Starting materials can be combined with suitable exothermic foaming agents to produce a foam upon vulcanization. Examples of suitable foaming agents include, but are not limited to, azodicarbonamide, azodiisobutyronitrile, 4,4-oxybenzene sulfonylsemicarbazide, and p-toiuene sulfonylsemicarbazide. Foaming agents can be provided in solid form so that they can be easily dry-blended with the starting material(s). In some embodiments, foaming agents are blended with a starting material in an amount sufficient to evolve from about 0.5 to about 3 moles of gas or vapor per kilogram of starting material. In one embodiment, dry azodicarbonamide is blended with EPDM and then vulcanized to produce a sealing layer.
The thickness of the sealing layer 120 can vary. In some embodiments, the sealing layer 120 can have generally the same thickness as the backing layer 110. In other embodiments, the thicknesses of the backing layer 110 and the sealing layer 120 can be generally different. For example, the sealing layer 120 can be about twice as thick as the backing layer 110. The sealing layer 120 and the backing layer 110 can be coupled together using any suitable technique. In some embodiments, the sealing layer 120 is adhered to the backing layer 110 using a suitable adhesive, for example, Chemlok® 250 available commercially from LORD Corporation. In other embodiments, other methods of coupling the sealing layer 120 and backing layer 110 together are utilized. The top surface area of the sealing layer 120 can also vary. In some embodiments, the sealing layer 120 can be sized to have substantially the top surface area as the backing layer 110. In various embodiments, the sealing layer 120 can have a top surface area that is substantially less than the top surface area of the backing layer 110. In one embodiment, the sealing layer 120 can form a ring with an inner diameter and an outer diameter that runs generally along the perimeter of the backing layer 110.
With reference to
The roto-cure machine 500 can include a heating drum 503, an infeed drum 501, an outfeed drum 505, a belt tension cylinder 507, a belt 509, and a radiator 511. The belt tension cylinder 507 is configured to drive the belt 509 and control the tension of the belt over the infeed drum 501, heating drum 503, and outfeed drum 505. The outfeed drum 505 and infeed drum 501 are positioned such that the belt 509 wraps around a portion of the heating drum 503 between the infeed drum and outfeed drum. This allows a user to input a piece of material, for example, a piece of uncured elastomer disposed over a metallic backing layer, in between the infeed drum 501 and heating drum 503 such that the material is compressed between the belt 509 and the heating drum 503. The radiator 511 is located near the heating drum 503 to apply heat to at least the portion of the heating drum 503 that the belt 509 wraps around. In some embodiments, the radiator 511 can be an infrared radiator or can use heated oil or steam to transfer heat to the heating drum 503. Other configurations can also be used.
The configuration schematically depicted in
In some embodiments, the roto-cure machine 500 can be configured to heat an uncured elastomer at about 370 degrees Farenheit for about 6 minutes and 30 seconds at a pressure of about 170 pound per square inch to vulcanize the elastomer. As discussed above, different heats, pressures, and times can be applied in various other embodiments. The dimensions of the infeed drum 501, heating drum 503, outfeed drum 805, belt tension cylinder 507 and belt 509 can vary.
In some embodiments, the heating drum 503 can have a diameter sized to subject an input material to a rotation of more than 180 degrees before ejection from the machine 500. In other embodiments, the heating drum 503 can be differently sized or positioned to subject an input material to more or less rotation.
With continued reference to
Comparing the vulcanizate layer 120 to the uncured elastomer layer 119 shows the change in volume the elastomer 119 undergoes during the vulcanization/roto-curing process. In some embodiments, the vulcanizate layer 120 can be between about 2 and about 4 times as thick as the uncured elastomer layer 119. This increased thickness can result in a vulcanizate layer 120 having a greater memory than the uncured elastomer layer 119 while maintaining other desirable characteristics.
In some embodiments, the roto-cure machine 500 can be configured to produce a memory foam vulcanizate when certain materials, for example, uncured EPDM mixed with a foaming agent, are input into the machine. As discussed below, the vulcanizate layer 120 can form a superior seal between the backing layer 110 and another surface than the uncured elastomer layer 119.
After ejection from the roto-cure machine 500, the vulcanizate layer 120 and backing layer 110 can be stamped or machined to form a plurality of individual washers. The washers can comprise different sizes and shapes depending upon their intended applications. In one embodiment, the washers can comprise roofing washers, for example, saddle washers or cyclone washers. After stamping or machining, the washers can be individually powder coated without harming the vulcanizate layer 120.
As discussed above, the sealing layer 120 can form a seal between a fastener and a roofing panel to prevent water and/or other contaminants from passing therethrough. Additionally, deformable vulcanizate sealing layers allow a user to apply a high torque to a fastener without damaging the surface underneath the washer 100 because of cushioning and increased flexibility.
The roofing washer 100 can rest on a portion of the roofing panel 210, for example, a crest. The roofing panel 210 can be formed of various materials, for example, polymers, composite materials, organic materials, recycled materials, and/or metals. The roofing panel 210 can cover a portion of the underlayment 220. In some embodiments, the underlayment 220 can comprise a roof The underlayment 220 can include one or more layers. In one embodiment, the underlayment 220 is a single wood layer. In another embodiment, the underlayment 220 includes a wood layer and a rubber membrane layer disposed over the wood layer.
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The foregoing description details certain embodiments of the devices and methods disclosed herein. It will be appreciated, however, that no matter how detailed the foregoing appears in text, the devices and methods can be practiced in many ways. As is also stated above, it should be noted that the use of particular terminology when describing certain features or aspects of the invention should not be taken to imply that the terminology is being re-defined herein to be restricted to including any specific characteristics of the features or aspects of the invention with which that terminology is associated. The scope of the disclosure should therefore be construed in accordance with the appended claims and any equivalents thereof
